PH12015501728B1

PH12015501728B1 - Industrial robot and industrial robot control method

Info

Publication number: PH12015501728B1
Application number: PH12015501728A
Authority: PH
Inventors: Takayuki Yazawa; Chikahiro Tanaka; Jun Otsuji; Hirokazu Watanabe; Junnosuke Koyama
Original assignee: Nidec Sankyo Corp
Priority date: 2013-02-13
Filing date: 2015-08-06
Publication date: 2015-11-09
Also published as: CN104995001B; PH12015501728A1; WO2014126112A1; TWI647078B; CN104995001A; TW201440974A; JPWO2014126112A1; JP6295243B2

Abstract

The present application provides an industrial robot that makes it possible to prevent damage in an automatic operation after completion of a teaching operation. In a robot 1; wherein a torque of the motors 15, 17, 19 and 22 (hereinafter, called the motors 15 and the like) for turning the motors 15 and the like in one direction is dealt with as a plus torque, and a torque of the motors 15 and the like for turning the motors 15 and the like in the other direction is dealt with as a minus torque; a control unit 5 turns the motors 15 and the like, in a test operation for the robot 1 to be carried out after the completion of the teaching operation, at a revolution speed lower than a revolution speed in a regular operation for the robot 1 to be carried out after the completion of the test operation; and furthermore, when the motors 15 and the like turn in the one direction in the teat operation, the motors 15 and the like are controlled with reference to a torque limit value lower than a torque limit value in the case of the motors 15 and the like turn in the other direction in the test operation, the motors 15 and the like are controlled with reference to a torque limit value higher than a torque limit value in the case of the motors 15 and the like turning in the other direction in the regular operation.

Description

the torque of the motor exceeds the torque limit value, or falls below the torque limit value.

Thus, according to the present invention, in the case where an operator becomes aware of a danger in a test operation, and triggers an emergency stop of the industrial robot, it becomes possible to shorten an idle running distance of the industrial robot.

Moreover, when the industrial robot touches a peripheral device and the like in a test operation, it becomes possible to stop the motor in a short time.

Therefore, according to the present invention, it becomes possible to prevent the industrial robot from getting damaged in a test operation. Moreover, in the case where a malfunction happens in a test operation; by way of carrying out a predetermined procedure such as a re-teaching operation, it becomes possible to prevent the industrial robot from touching a peripheral device and the like in a regular operation after completion of the test operation, so as to prevent the industrial robot from getting damaged in the regular operation. As a result, according to the present invention, it becomes possible to prevent the industrial robot from getting damaged in an automatic operation after completion of the teaching operation.

According to the present invention, it is preferable that the industrial robot includes a moving up/down motor, as the motor for moving up and down an end effector; and in the case where a torque limit value for the moving up/down motor at a time when the end effector moves up in the test operation is dealt with as a first torque limit value; and a torque limit value for the moving up/down motor at a time when the end effector moves down is dealt with as a second torque limit value; the first torque limit value and the second torque limit value are specified in the control unit, in such a way that an absolute value of the second torque limit value is smaller than an absolute value of the first torque limit value; and the control unit controls the moving up/down motor, on the basis of the first torque limit value, at the time when the end effector moves up in the test operation; and controls the moving up/down motor, on the basis of the second torque limit value, at the time when the end effector moves down in the test operation.

In general, owing to an impact of weight of the end effector, and a workpiece held by the end effector, and the like; an absolute value of a torque required for the moving up/down motor at the time of moving up the end effector becomes great, and an absolute value of a torque required for the moving up/down motor at the time of moving down the end effector becomes small.

Nevertheless, according to the configuration described above, the first torque limit value and the second torque limit value are specified in such a way that an absolute value of the second torque limit value is smaller than an absolute value of the first torque limit value. Therefore, the first torque limit value can be specified according to the torque required for the moving up/down motor at a time when the end effector moves up, in such a way that; when the end effector normally moves up, the torque of the moving up/down motor, for example, does not exceed the first torque limit value in order not to stop the moving up/down motor; and meanwhile, when the end effector and the like touch a peripheral device and the like, the torque of the moving up/down motor, for example, does exceed the first torque limit value. On the other hand, the second torque limit value can be specified according to the torque required for the moving up/down motor at a time when the end effector moves down, in such a way that; when the end effector normally moves down, the torque of the moving up/down motor, for example, does not fall below the second torque limit value in order not to stop the moving up/down motor; and meanwhile, when the end effector and the like touch a peripheral device and the like, the torque of the moving up/down motor, for example, does fall below the second torque limit value. According to this configuration, the moving up/down motor is controlled, on the basis of the first torque limit value, at the time when the end effector moves up; and on the other hand, the moving up/down motor is controlled, on the basis of the second torque limit value, at the time when the end effector moves down. Therefore, when the end effector and the like touch a peripheral device and the like at the time of moving up and down the end effector so that the torque of the moving up/down motor exceeds or falls below a torque limit value, it becomes possible to stop the moving up/down motor for preventing the end effector and the like from getting damaged. Moreover, when the end effector normally moves up and down, it becomes possible to appropriately move up and down the end effector, by way of keeping on turning the moving up/down motor.

According to the present invention, it is preferable that the industrial robot includes a pendant switch electrically connected to the control unit; and a motor load containing at least one of weight of the end effector and weight of a workpiece held by the end effector can be entered by use of the pendant switch; and the control unit sets the first torque limit value and the second torque limit value, on the basis of the motor load to be entered by use of the pendant switch.

According to this configuration, the first torque limit value and the second torque limit value can be specified according to a motor load, so as to make it possible to move up and down the end effector further appropriately, and so as to make a torque of the moving up/down motor exceed or fall below a torque limit value for sure when the end effector and the like touch a peripheral device and the like. Therefore, it becomes possible to move up and down the end effector further appropriately, and to surely prevent the end effector and the like from getting damaged.

According to the present invention, for example, the industrial robot includes: a main body; a first arm section whose root end side is connected to the main body so as to be rotatable; a second arm section whose root end side is connected to a top end side of the first arm section so as to be rotatable; and an end effector located at a top end side of the second arm section; and the industrial robot furthermore includes, as the motor for operatoin, a first rotating motor for rotating the first arm section with respect to the main body; a second rotating motor for rotating the second arm section with respect to the first arm section; a turning motor for turning the end effector with respect to the second arm section; and a moving up/down motor for moving the end effector up and down with respect to the second arm section.

According to the present invention, it is preferable that the industrial robot includes: a main body; a first arm section whose root end side is connected to the main body so as to be rotatable; a second arm section whose root end side is connected to a top end side of the first arm section so as to be rotatable; an end effector located at a top end side of the second arm section; a first rotating motor for rotating the first arm section with respect to the main body; a second rotating motor for rotating the second arm section with respect to the first arm section; and a turning motor for turning the end effector with respect to the second arm section; and the industrial robot includes a moving up/down motor, as the motor for operation, for moving the end effector up and down with respect to the second arm section; and in the test operation, the control unit individually turns the first rotating motor, the second rotating motor, and the turning motor at a revolution speed that is the same as a revolution speed for the regular operation; and individually controls the motors with reference to a torque limit value that is the same as a torque limit value for the regular operation; and in the test operation, the control unit turns the moving up/down motor at a revolution speed slower than a revolution speed for the regular operation; and in the case where the moving up/down motor turns in one direction in the test operation, the control unit controls the moving up/down motor with reference to a torque limit value lower than a torque limit value in the case of turning the moving up/down motor in the one direction in the regular operation; and in the case where the moving up/down motor turns in the other direction in the test operation, the control unit controls the moving up/down motor with reference to a torque limit value higher than a torque limit value in the case of turning the moving up/down motor in the other direction in the regular operation.

Owing to an impact of weight of the end effector, a workpiece held by the end effector, and the like; the end effector and the like at the time of moving down are likely to get damaged if they touch a peripheral device and the like. Nevertheless, according to the configuration described above, it becomes possible to stop the moving up/down motor for moving up and down the end effector in a short time when the end effector and the like touch a peripheral device and the like in the test operation, and moreover a moving distance of the end effector after stopping the the moving up/down motor can be shortened. Accordingly, it becomes possible to prevent the end effector and the like from getting damaged in the test operation. Furthermore, according to this configuration; the first rotating motor, the second rotating motor, and the turning motor in the test operation individually turn at a revolution speed that is the same as a revolution speed for the regular operation, and therefore an operation speed of the industrial robot in the test operation can be increased.

According to the present invention, it is preferable that a revolution speed and a torque limit value for the motor in the test operation are selectable in the control unit. According to this configuration, the test operation for the industrial robot can be carried out by use of various combinations of a revolution speed and a torque limit value for the motor.

To bring a solution for the second subject described above, an industrial robot according to the present invention (a second invention) includes: a motor for operation; and a control unit for controlling the motor; wherein, a maximum absolute value of a torque required for the motor at a time when the motor turns in one direction is greater than a maximum absolute value of a torque required for the motor at a time when the motor turns in the other direction; and in the case where a torque limit value for the motor at the time of turning in the one direction is dealt with as a first torque limit value; and a torque limit value for the motor at the time of turning in the other direction is dealt with as a second torque limit value; the first torque limit value and the second torque limit value are specified in the control unit, in such a way that an absolute value of the second torque limit value is smaller than an absolute value of the first torque limit value; and the control unit controls the motor, on the basis of the first torque limit value, at the time when the motor turns in the one direction; and controls the motor, on the basis of the second torque limit value, at the time when the motor turns in the other direction.

Furthermore, to bring a solution for the second subject described above, a control method of an industrial robot according to the present invention

(the second invention) is a control method of an industrial robot including a motor for operation; wherein, a maximum absolute value of a torque required for the motor at a time when the motor turns in one direction is greater than a maximum absolute value of a torque required for the motor at a time when the motor turns in the other direction; and in the case where a torque limit value for the motor at the time of turning in the one direction is dealt with as a first torque limit value; and a torque limit value for the motor at the time of turning in the other direction is dealt with as a second torque limit value; the first torque limit value and the second torque limit value are specified in such a way that an absolute value of the second torque limit value is smaller than an absolute value of the first torque limit value; and the motor is controlled, on the basis of the first torque limit value, at the time when the motor turns in the one direction; and the motor is controlled, on the basis of the second torque limit value, at the time when the motor turns in the other direction.

According to the present invention, a maximum absolute value of a torque required for the motor at a time when the motor turns in one direction is greater than a maximum absolute value of a torque required for the motor at a time when the motor turns in the other direction. Furthermore, according to the present invention, the first torque limit value and the second torque limit value are specified in such a way that an absolute value of the second torque limit value, which is a torque limit value for the motor at the time of turning in the other direction, is smaller than an absolute value of the first torque limit value, which is a torque limit value for the motor at the time of turning in the one direction. Therefore, in the present invention, the first torque limit value can be specified according to the torque required for the motor at the time of turning in the one direction, in such a way that when the motor turns in the one direction and the industrial robot normally operates, the torque of the motor, for example, does not exceed the first torque limit value in order not to stop the motor; and meanwhile, when the motor turns in the one direction and a part of the industrial robot touches a peripheral device and the like, the torque of the motor, for example, does exceed the first torque limit value. On the other hand, the second torque limit value can be specified according to the torque required for the motor at the time of turning in the other direction, in such a way that when the motor turns in the other direction and the industrial robot normally operates, the torque of the motor, for example, does not fall below the second torque limit value in order not to stop the motor; and meanwhile, when the motor turns in the other direction and a part of the industrial robot touches a peripheral device and the like, the torque of the motor, for example, does fall below the second torque limit value.

Moreover, according to the present invention; the motor is controlled, on the basis of the first torque limit value, at the time when the motor turns in the one direction; and the motor is controlled, on the basis of the second torque limit value, at the time when the motor turns in the other direction.

Therefore, according to the present invention; in the case where a part of the industrial robot touches a peripheral device and the like at the time when the motor turns to operate the industrial robot so that the torque of the motor exceeds or falls below a torque limit value, it becomes possible to stop the motor for preventing the industrial robot, a peripheral device and the like from getting damaged. Moreover, according to the present invention; when the motor turns to normally operate the industrial robot, it becomes possible to appropriately operate the industrial robot, by way of keeping on turning the motor.

In the case of an industrial robot according the present invention, for example, the industrial robot is installed in the atmosphere; and the motor is a moving up/down motor for moving up and down an end effector; and when the motor turns in the one direction, the end effector moves up; and when the motor turns in the other direction, the end effector moves down; and the first torque limit value is a torque limit value for the motor at the time of moving up the end effector, and meanwhile the second torque limit value is a torque limit value for the motor at the time of moving down the end effector; and the control unit controls the motor, on the basis of the first torque limit value, at a time when the end effector moves up; and controls the moving up/down motor, on the basis of the second torque limit value, at a time when the end effector moves down.

Moreover, in the case of a control method of an industrial robot according to the present invention; for example, the industrial robot is installed in the atmosphere; and the motor is a moving up/down motor for moving up and down an end effector; and when the motor turns in the one direction, the end effector moves up; and when the motor turns in the other direction, the end effector moves down; and the first torque limit value is a torque limit value for the motor at the time of moving up the end effector, and meanwhile the second torque limit value is a torque limit value for the motor at the time of moving down the end effector; and the motor is controlled, on the basis of the first torque limit value, at a time when the end effector moves up; and the moving up/down motor is controlled, on the basis of the second torque limit value, at a time when the end effector moves down.

In this case, the first torque limit value can be specified according to the torque required for the motor at a time when the end effector moves up, in such a way that; when the end effector normally moves up, the torque of the motor, for example, does not exceed the first torque limit value in order not to stop the motor; and meanwhile, when the end effector and the like touch a peripheral device and the like, the torque of the motor, for example, does exceed the first torque limit value. On the other hand, the second torque limit value can be specified according to the torque required for the motor at a time when the end effector moves down, in such a way that; when the end effector normally moves down, the torque of the motor, for example, does not fall below the second torque limit value in order not to stop the motor; and meanwhile, when the end effector and the like touch a peripheral device and the like, the torque of the motor, for example, does fall below the second torque limit value.

Moreover, in this case, the moving up/down motor is controlled, on the basis of the first torque limit value, at the time when the end effector moves up; and on the other hand, the moving up/down motor is controlled, on the basis of the second torque limit value, at the time when the end effector moves down.

Therefore, when the end effector and the like touch a peripheral device and the like at the time of moving up and down the end effector so that the torque of the motor exceeds or falls below a torque limit value, it becomes possible to stop the motor for preventing the end effector and the like from getting damaged.

Moreover, when the end effector normally moves up and down, it becomes possible to appropriately move up and down the end effector, by way of keeping on turning the motor.

According to this configuration, the first torque limit value and the second torque limit value can be specified according to a motor load, so as to make it possible to move up and down the end effector further appropriately, and so as to make a torque of the motor exceed or fall below a torque limit value for sure when the end effector and the like touch a peripheral device and the like. Therefore, it becomes possible to move up and down the end effector further appropriately, and to surely prevent the end effector and the like from getting damaged.

According to the present invention, it is preferable that the control unit obtains a motor load of the motor, by way of operating the motor; and sets the first torque limit value and the second torque limit value, on the basis of the motor load obtained.

According to this configuration, the first torque limit value and the second torque limit value can be specified according to a motor load, so as to make it possible to operate the industrial robot further appropriately, and so as to make a torque of the motor exceed or fall below a torque limit value for sure when a part of the industrial robot touches a peripheral device and the like. Therefore, it becomes possible to operate the industrial robot further appropriately, and to surely prevent the industrial robot, the peripheral device and the like from getting damaged.

According to the present invention, for example, the first torque limit value and the second torque limit value corresponding to the motor load, being listed in a table, are stored in the control unit; and then, according to the motor load, the control unit reads out and sets the corresponding first torque limit value and second torque limit value.

According to the present invention, it is preferable that at least the control unit controls the motor, on the basis of the first torque limit value, at the time of moving up the end effector in a teaching operation for the industrial robot; and controls the motor, on the basis of the second torque limit value, at the time of moving down the end effector in a teaching operation for the industrial robot. A teaching operation for the industrial robot through a manual operation by an operator creates a greater chance that the end effector and the like touch a peripheral device and the like, so as to make the end effector and the like damaged, being compared to an automatic operation of the industrial robot after completion of a teaching operation. Therefore, according to this configuration, it becomes possible to prevent the end effector and the like from getting damaged even in a teaching operation.

According to the present invention, it is preferable that the control unit controls the motor, on the basis of the first torque limit value, at the time of moving up the end effector in an automatic operation of the industrial robot after completion of a teaching operation; and controls the motor, on the basis of the second torque limit value, at the time of moving down the end effector in the automatic operation; and meanwhile, the first torque limit value in the teaching operation and the first torque limit value in the automatic operation are different from each other; and the second torque limit value in the teaching operation and the second torque limit value in the automatic operation are different from each other. According to this configuration, the first torque limit value and the second torque limit value in the automatic operation can be set in such a way that a revolution speed of the motor in the automatic operation is faster than a revolution speed of the motor in the teaching operation. Accordingly, a speed of moving the end effector up and down in an automatic operation can be made faster.

According to the present invention, for example, the industrial robot includes an end effector fixing member to which the end effector is fixed; and the motor moves up and down the end effector and the end effector fixing member.

According to the present invention, for example, the industrial robot includes; an end effector; an end effector fixing member to which the end effector is fixed; a shaft component so placed as to have its axis direction in a vertical direction, and provided with the end effector fixing member fixed to its upper end; a case body in which at least a lower end side of the shaft component is housed; and a bellows placed so as to cover an outer circumference side of the shaft component, while one end of the bellows being fixed to the case body and the other end of the bellows being fixed to the shaft component; and the motor is a moving up/down motor for moving up and down the end effector, the end effector fixing member and the shaft component, with respect to the case body; and the end effector and the end effector fixing member are located in a vacuum, and one of an inner circumference side and an outer circumference side of the bellows is kept in a vacuum, while the other of the inner circumference side and the outer circumference side of the bellows is in the atmosphere; and when the motor turns in one direction, the end effector moves down, and when the motor turns in the other direction, the end effector moves up; and

GGG. the first torque limit value is a torque limit value for the motor at the time of moving down the end effector, and the second torque limit value is a torque limit value for the motor at the time of moving up the end effector; and the control unit controls the motor, on the basis of the first torque limit value, at the time when the end effector moves down; and controls the moving up/down motor, on the basis of the second torque limit value, at the time when the end effector moves up.

In this case, the end effector and the end effector fixing member are located in a vacuum. Then, if the shaft component moves down together with the end effector and the end effector fixing member in such a way as to expand the bellows, a negative pressure is generated to exert a great force so as to move upward the end effector and so on. Therefore, an absolute value of a torque required for the motor at the time of moving down the end effector becomes great, and meanwhile an absolute value of a torque required for the motor at the time of moving up the end effector sometimes becomes small. Nevertheless, even in this case, the first torque limit value can be specified according to the torque required for the motor at a time when the end effector moves down, in such a way that; when the end effector normally moves down, the torque of the motor, for example, does not fall below the first torque limit value in order not to stop the motor; and meanwhile, when the end effector and the like touch a peripheral device and the like, the torque of the motor, for example, does fall below the first torque limit value. On the other hand, the second

SSS torque limit value can be specified according to the torque required for the motor at a time when the end effector moves up, in such a way that; when the end effector normally moves up, the torque of the motor, for example, does not exceed the second torque limit value in order not to stop the motor; and meanwhile, when the end effector and the like touch a peripheral device and the like, the torque of the motor, for example, does exceed the second torque limit value.

Moreover, in this case, the moving up/down motor is controlled, on the basis of the first torque limit value, at the time when the end effector moves down; and on the other hand, the moving up/down motor is controlled, on the basis of the second torque limit value, at the time when the end effector moves up.

According to the present invention, for example, the industrial robot is a battery change robot equipped with a battery extracting/inserting mechanism for extracting a battery from a battery storage section, which is fixed to a vehicle and in which the battery is stored, and inserting a battery into the battery storage section; and the battery extracting/inserting mechanism includes a battery engaging unit for engaging with the battery; and the motor is an extracting/inserting motor for transferring the battery engaging unit; and when the motor turns in one direction, the battery engaging unit inserts the battery into the battery storage section; and when the motor turns in the other direction, the battery engaging unit extracts the battery from the battery storage section; and the first torque limit value is a torque limit value for the motor at a time when the battery engaging unit inserts the battery into the battery storage section, and the second torque limit value is a torque limit value for the motor at a time when the battery engaging unit extracts the battery from the battery storage section; and the control unit controls the motor, on the basis of the first torque limit value at the time of inserting the battery; and controls the moving up/down motor, on the basis of the second torque limit value, at the time of extracting the battery.

In this case, the first torque limit value can be specified according to the torque required for the motor at a time of inserting the battery, in such a way that; when the battery engaging unit normally carries out an inserting motion, the torque of the motor, for example, does not exceed the first torque limit value in order not to stop the motor; and meanwhile, when the battery engaging unit and the like touch a peripheral device and the like, the torque of the motor, for example, does exceed the first torque limit value. On the other hand, the second torque limit value can be specified according to the torque required for the motor at a time of extracting the battery, in such a way that; when the battery engaging unit normally carries out an extracting motion, the torque of the motor, for example, does not fall below the second torque limit value in order not to stop the motor; and meanwhile, when the battery engaging unit and the like touch a peripheral device and the like, the torque of the motor, for example, does fall below the second torque limit value. Moreover, in this case, the motor is controlled, on the basis of the first torque limit value, at the time of inserting the battery; and on the other hand, the moving up/down motor is controlled, on the basis of the second torque limit value, at the time of extracting the battery. Therefore, when the battery engaging unit and the like touch a peripheral device and the like at the time of changing the battery so that the torque of the motor exceeds or falls below a torque limit value, it becomes possible to prevent the battery engaging unit and the like from getting damaged. Moreover, when the battery engaging unit normally operates at the time of changing the battery, it becomes possible to appropriately operate the battery engaging unit, by way of keeping on turning the motor. [Advantageous Effect of the Invention]

As described above, the present invention (the first invention) makes it possible to prevent an industrial robot from getting damaged in an automatic operation after a teaching operation finishes.

Furthermore, the present invention (the second invention) makes it possible to prevent an industrial robot, a peripheral device, and the like from getting damaged, and moreover enables an appropriate operation of the industrial robot. [Brief Description of the Drawings]

FIG. 1 is a side view drawing for explaining a structure of an industrial robot according to an embodiment of the present invention.

FIG. 2 is a graph for explaining a torque limit value of a first rotating motor shown in FIG. 1.

FIG. 3 is a graph for explaining a torque limit value of a moving up/down motor shown in FIG. 1.

FIG. 4 is a list for explaining an example of a table showing torque limit values stored in a control unit illustrated in FIG. 1.

FIG. 5 is a graph for explaining a torque limit value of a moving up/down motor shown in FIG. 1.

FIG. 6 is a list for explaining an example of a table showing torque limit values stored in the control unit illustrated in FIG. 1.

FIG. 7 is a plan view drawing of an industrial robot according to another embodiment of the present invention.

FIG. 8 is a side view drawing that shows the industrial robot, viewed along the arrows ‘E’ & ‘E’ in

FIG. 7.

FIG. 9 is a side view drawing of an industrial robot according to another embodiment of the present invention.

FIG. 10 is a plan view for explaining a moving up/down mechanism of the industrial robot shown in FIG. 9.

; . In es

INDUSTRIAL ROBOT AND INDUSTRIAL ROBOT CONTROL METHOD

[Field of the Invention]

The present invention relates to an industrial robot and an industrial robot control method. [Background]

A SCARA robot (Selective Compliance Assembly Robot

Arm) to be used in a part assembly line and the like is traditionally known (for example, refer to Patent

Document 1). A robot described in Patent Document 1 includes: a supporting arm; a first arm connected to the supporting arm in such a way as to be rotatable; a second arm connected to the first arm in such a way as to be rotatable; and a third arm that is connected to the second arm in such a way as to be rotatable, and able to move up and down with respect to the second arm. The robot further includes; a motor for rotating the first arm around the supporting arm; a motor for rotating the second arm around the first arm; a motor for rotating the third arm around the second arm; and a motor for moving the third arm up and down with respect to the second arm. In the case of the robot, at a time of teaching the robot (teaching operation), turning the four motors at low speed and lessening their motor current limit values prevents the robot from colliding with a peripheral device in the teaching operation. [Prior Art Document] [Patent Document]

Patent Document 1: Japanese Unexamined Patent

Application Publication No. SH063-68390

FIG. 11 includes drawings of an industrial robot according to another embodiment of the present invention, wherein FIG. 11A and FIG. 11B are a plan view drawing and a side view drawing, respectively.

FIG. 12 is a cross-section view for explaining an internal structure of a section ‘F’ of FIG. 11B.

FIG. 13 is a perspective view of a battery change system in which an industrial robot according to another embodiment of the present invention is placed.

FIG. 14 is a perspective view showing a section ‘G’ of FIG. 13, viewed from another angle.

FIG. 15 is a schematic view for explaining a structure of a battery and a battery storage section shown in FIG. 13.

FIG. 16 is a drawing that shows a battery extracting/inserting mechanism and a moving up/down mechanism shown in FIG. 14, in a front elevation view.

FIG. 17 is a drawing that shows the battery extracting/inserting mechanism and the moving up/down mechanism, viewed along the line ‘H-H’ in FIG. 16.

FIG. 18 is a drawing for explaining a battery transfer mechanism shown in FIG. 16, in its side view.

FIG. 19 is a perspective view of an industrial robot according to another embodiment of the present invention.

FIG. 20 is a perspective view of an industrial robot according to still another embodiment of the present invention. [Description of the Preferred Embodiments]

Embodiments of the present invention are described below with reference to the accompanying drawings.

(Structure common to the first embodiment and the second embodiment) (Structure of the industrial robot)

FIG. 1 is a side view drawing for explaining a structure of an industrial robot 1 according to an embodiment of the present invention. In the explanation below, a direction ‘Z’ shown in FIG. 1 is referred to as a vertical direction. Incidentally, a ‘21’ direction side and a ‘Z2’ direction side are referred to as an upward side and a downward side, respectively.

The industrial robot 1 according to the present embodiment (hereinafter called “the robot 17”) is a

SCARA robot (Selective Compliance Assembly Robot Arm), which is installed and used in a component manufacturing line, an assembly line, and the like, while the robot being installed in the atmosphere. The robot 1 includes; a main body 2, an arm 3 whose root end side is connected to the main body 2 so as to be rotatable, a ball screw spline 4 assembled at a top end side of the arm 3. The ball screw spline 4 is equipped with an end effector that is not illustrated.

Moreover, the robot 1 is provided with a control unit 5 for controlling the robot 1 and a pendant switch 6 electrically connected to the control unit 5.

The main body 2 is approximately shaped so as to be cylindrical. A bottom end side of the main body 2 is fixed to a frame 7 that is, for example, a part of a production line or an assembly line. The arm 3 is structured with two arm sections that are a first arm section 11 and a second arm section 12 positioned at an upper side of the first arm section 11. A root end side of the first arm section 11 is connected to the main body 2 so as to be rotatable, and meanwhile a root end side of the second arm section 12 is connected to a top end side of the first arm section 11 so as to be rotatable.

At a joint part connecting the main body 2 and the first arm section 11, there are placed a motor 15 as a first rotating motor for rotating the first arm section 11 with respect to the main body 2, and a gear reducer 16 that transmits drive power of the motor 15 while slowing down speed. The motor 15 is a servo motor.

Concretely to describe, the motor 15 is an AC servo motor. An output shaft of the motor 15 is fixed to an input unit of the gear reducer 16, and the root end side of the first arm section 11 is fixed to an output unit of the gear reducer 16. Meanwhile, a main section of the motor 15 is fixed to a case body of the gear reducer 16. Then, the case body of the gear reducer 16 is fixed to the main body 2.

At a joint part connecting the first arm section 11 and the second arm section 12, there are placed a motor 17 as a second rotating motor for rotating the second arm section 12 with respect to the first arm section 11, and a gear reducer 18 that transmits drive power of the motor 17 while slowing down speed. The motor 17 is a servo motor. Concretely to describe, the motor 17 is an AC servo motor. An output shaft of the motor 17 is fixed to an input unit of the gear reducer 18, and the top end side of the first arm section 11 is fixed to an output unit of the gear reducer 18.

Meanwhile, a main section of the motor 17 is fixed to a case body of the gear reducer 18. Then, the case body of the gear reducer 18 is fixed to the root end side of the second arm section 12.

At the second arm section 12, there are installed a motor 19 as a turning motor for turning the end effector with respect to the second arm section 12, and a gear reducer 20 that transmits drive power of the motor 19 while slowing down speed. The motor 19 is a servo motor. Concretely to describe, the motor 19 is an AC servo motor. An output shaft of the motor 19 is fixed to an input unit of the gear reducer 20, and a pulley 21 is fixed to an output unit of the gear reducer 20. Meanwhile, a main section of the motor 19 is fixed to a case body of the gear reducer 20. Then, the case body of the gear reducer 20 is fixed onto an upper surface of the second arm section 12.

Moreover, at the second arm section 12, there are installed the ball screw spline 4, and a motor 22 as a moving up/down motor for moving the end effector up and down with respect to the second arm section 12. The ball screw spline 4 includes; a ball screw spline shaft 23 having its shaft direction in a vertical direction, a ball screw nut 24 for moving the ball screw spline shaft 23 in the vertical direction, and a spline nut 25 for turning the ball screw spline shaft 23 around a shaft center of the ball screw spline shaft 23 as a turning center. The motor 22 is a servo motor.

Concretely to describe, the motor 22 is an AC servo motor. A pulley 28 is fixed to an output shaft of the motor 22. A pulley 29 is fixed to the ball screw nut 24. In the meantime, a belt 30 is installed across between the pulley 28 and the pulley 29. A pulley 31 is fixed to the spline nut 25. Meanwhile, a belt 32 is installed across between the pulley 21 and the pulley 31.

The ball screw nut 24 and the spline nut 25 are held by a holder part 33, approximately shaped so as to be cylindrical, in such a way as to be rotatable. A plate is fixed at an upper end of the holder part 33, and then a main section of the motor 22 is fixed to the plate. A lower end of the holder part 33 is fixed to the upper surface of the second arm section 12.

Meanwhile, the end effector is assembled at a lower end of the ball screw spline shaft 23. In other words, the end effector is fixed to a top end side of the second arm section 12. The ball screw spline shaft 23 in the present embodiment is an end effector fixing member to which the end effector is fixed.

Then, at a lower end side of the ball screw spline shaft 23, a bellows fixing part 35, to which a lower end of a bellows 34 is fixed, is assembled by the intermediary of a bearing unit. On the other hand, an upper end of the bellows 34 is fastened to a cover fixed at a bottom surface of the second arm section 12.

Then, at a higher end side of the ball screw spline shaft 23, a bellows fixing part 37, to which an upper end of a bellows 36 is fixed, is assembled by the intermediary of a bearing unit. On the other hand, a lower end of the bellows 36 is fastened to a cover 38 that covers the motor 17, the motor 19, the motor 22, and the like. Then, the cover 38 is assembled at an upper surface side of the second arm section 12.

In the present embodiment; when the motor 22 turns, drive power of the motor 22 is transmitted to the ball screw nut 24 by the intermediary of the pulley

28, the pulley 29, and the belt 30 so that the ball screw nut 24 turns in such a way as to move the ball screw spline shaft 23 up and down. Namely, when the motor 22 turns in one direction, the end effector assembled at the lower end of the ball screw spline shaft 23 moves upward together with the ball screw spline shaft 23; and meanwhile when the motor 22 turns in the other direction, the end effector assembled at the lower end of the ball screw spline shaft 23 moves downward together with the ball screw spline shaft 23.

Moreover, when the motor 19 turns, the drive power of the motor 19 is transmitted to the spline nut 25 by the intermediary of the pulley 21, the pulley 31, and the belt 32 so that the spline nut 25 turns and the ball screw spline shaft 23 turns around its shaft center as a turning center. In other words, the end effector assembled at the lower end of the ball screw spline shaft 23 turns around the shaft center of the ball screw spline shaft 23 as a turning center.

The motors 15, 17, 19 and 22 are electrically connected to the control unit 5, which controls the motors 15, 17, 19 and 22. The pendant switch 6 is connected to the unit 5 through a predetermined cable.

Incidentally, in the first embodiment, the motors 15, 17, 19 and 22 are motors for operation for operating the robot 1; and meanwhile in the second embodiment, the motor 22 is a motor for operation for operating the robot 1. (The first embodiment) (Revolution speed and torque limit value of motor)

FIG. 2 is a graph for explaining a torque limit value of the motor 15 shown in FIG. 1. FIG. 3 is a graph for explaining a torque limit value of the motor 22 shown in FIG. 1. FIG. 4 is a list for explaining an example of a table showing torque limit values stored in the control unit 5 illustrated in FIG. 1.

After the robot 1 is installed in an assembly line and the like, a teaching operation for the robot 1 is carried out. Then, the robot 1 after the teaching operation is automatically operated on the basis of a teaching result. In the present embodiment, after the teaching operation finishes, a test operation is carried out as an automatic operation of the robot 1, in order to make sure whether or not a teaching point and a control program for the robot 1 are correct.

Then, after the test operation finishes, a regular operation for executing a part assembling work and so on is carried out as an automatic operation of the robot 1. Incidentally, switching between a test operation and a regular operation is carried out by an operation of an operator by using the pendant switch 6.

Moreover, for preventing the robot 1 and so on from damage by way of stopping the motors 15, 17, 19 and 22 (namely, by way of stopping operation of the robot 1) in the case where the robot 1 in action touches a peripheral device of the robot 1 and the like, torque limit values for the motors 15, 17, 19 and 22 are specified in the control unit 5. If a torque of the motors 15, 17, 19 and 22 reaches its limit value, the control unit 5 stops the motors 15, 17, 19 and 22.

In the present embodiment; in a test operation, the control unit 5 individually turns the motors 15, 17, 19 and 22 at a revolution speed slower than a revolution speed for a regular operation. For example,

in such a test operation, the control unit 5 individually turns the motors 15, 17, 19 and 22 at an approximately 10% speed of a revolution speed for a regular operation.

Moreover, wherein a torque of the motors 15, 17, 19 and 22 for turning the motors 15, 17, 19 and 22 in one direction is dealt with as a plus torque, and a torque of the motors 15, 17, 19 and 22 for turning the motors 15, 17, 19 and 22 in the other direction is dealt with as a minus torque; according to the present embodiment; in the test operation, the control unit 5 determines whether the motors 15, 17, 19 and 22 turn in the one direction, or in the other direction; and furthermore, in the case where the motors 15, 17, 19 and 22 turn in the one direction, the control unit 5 individually controls the motors 15, 17, 19 and 22 with reference to a torque limit value lower than a torque limit value in the case of the motors 15, 17, 19 and 22 turning in the one direction in a regular operation; and meanwhile, in the case where the motors 15, 17, 19 and 22 turn in the other direction, the control unit 5 individually controls the motors 15, 17, 19 and 22 with reference to a torque limit value higher than a torque limit value in the case of the motors 15, 17, 19 and 22 turning in the other direction in a regular operation.

Incidentally, in the present embodiment, torque limit values for the motors 15, 17, 19 and 22 at the time of a test operation are the same as torque limit values for the motors 15, 17, 19 and 22 at the time of a teaching operation for the robot 1.

Meanwhile at this point, even though a turning direction of the motor 15 changes, an absolute value of a torque required for the motor 15 does not change on a large scale owing to an impact of gravity force of the arm 3, the ball screw spline 4, and the like. In the case where, after a servo control starts, the first arm section 11 having stayed at a predetermined position is rotated in one direction with respect to the main body 2, and then after being stopped for a predetermined time, the first arm section 11 is rotated in the other direction with respect to the main body 2, a torque of the motor 15 changes, for example, as shown in FIG. 2.

Concretely to describe, a torque of the motor 15 in a test operation changes, for example, as a curve Sl shows in FIG. 2, and meanwhile a torque of the motor 15 in a regular operation changes, for example, as a curve

S2 shows in FIG. 2.

Therefore, an absolute value of a torque limit value T1 for the motor 15 at the time of turning the motor 15 in the one direction in a test operation and an absolute value of a torque limit value T2 for the motor 15 at the time of turning the motor 15 in the other direction in the test operation are almost the same. Meanwhile, an absolute value of a torque limit value T3 for the motor 15 at the time of turning the motor 15 in the one direction in a regular operation and an absolute value of a torque limit value T4 for the motor 15 at the time of turning the motor 15 in the other direction in the regular operation are almost the same. Incidentally, as described above; in the case where the motor 15 turns in the one direction in a test operation, the motor 15 is controlled with reference to the torque limit value T1 that is lower than the torque limit value T3 in the case of the motor 15 turning in the one direction in a regular operation; and then in the case where the motor 15 turns in the other direction in a test operation, the motor 15 is controlled with reference to the torque limit value T2 that is higher than the torque limit value T4 in the case of the motor 15 turning in the other direction in a regular operation.

Similarly, even though a turning direction of the motors 17 and 19 changes, an absolute value of a torque required for the motors 17 and 19 does not change on a large scale owing to an impact of gravity force of the arm 3, the ball screw spline 4, and the like.

Therefore, an absolute value of a torque limit value for the motor 17 at the time of turning the motor 17 in the one direction in a test operation and an absolute value of a torque limit value for the motor 17 at the time of turning the motor 17 in the other direction in the test operation are almost the same. Meanwhile, an absolute value of a torque limit value for the motor 17 at the time of turning the motor 17 in the one direction in a regular operation and an absolute value of a torque limit value for the motor 17 at the time of turning the motor 17 in the other direction in the regular operation are almost the same. Then, an absolute value of a torque limit value for the motor 19 at the time of turning the motor 19 in the one direction in a test operation and an absolute value of a torque limit value for the motor 19 at the time of turning the motor 19 in the other direction in the test operation are almost the same. Meanwhile, an absolute value of a torque limit value for the motor 19 at the time of turning the motor 19 in the one direction in a

[Summary of Invention] [Problem to Be Solved]

In the case of such a robot as described in Patent

Document 1, an automatic operation is carried out after teaching operation finishes. In the case where the teaching operation for the robot is unfortunately not carried out in a proper manner, there is a chance that the robot may touch a peripheral device and the like of the robot in the automatic operation of the robot so that the robot may get damaged.

Then, in the case of a Selective Compliance

Assembly Robot Arm, such as a robot described in Patent

Document 1, an end effector is assembled onto the third arm. Meanwhile, sometimes the end effector holds a predetermined workpiece. Therefore, owing to an effect of weight of the third arm, the end effector, the workpiece, and the like, an absolute value of a torque required for the motor to move the third arm up and down (the moving up/down motor) becomes large at a time of moving up the third arm; and in the meantime, an absolute value of a torque required for the moving up/down motor becomes small at a time of moving down the third arm.

In general, for prevention of any damage to the end effector and the like in the case where the end effector and the like touch a peripheral device and so on, a torque limit value is specified for the moving up/down motor. If a torque of the moving up/down motor reaches the torque limit value, the moving up/down motor gets stopped. Moreover, an absolute value of a torque limit value of the moving up/down motor at the time of moving up the third arm, and an absolute value

SS —————————— regular operation and an absolute value of a torque limit value for the motor 19 at the time of turning the motor 19 in the other direction in the regular operation are almost the same.

On the other hand, the motor 22 moves up and down the ball screw spline shaft 23 together with the end effector. Therefore, owing to an impact of weight of the ball screw spline shaft 23, the end effector, a workpiece held by the end effector, and the like; an absolute value of a torque required for the motor 22 at the time of moving up the end effector becomes great, and an absolute value of a torque required for the motor 22 at the time of moving down the end effector becomes small. In the case where turning the motor 22 in one direction moves up the end effector and turning the motor 22 in the other direction moves down the end effector; when the end effector having stayed at a predetermined position moves up after a servo control starts and then the end effector moves down after being stopped for a predetermined time, a torque of the motor 22 changes, for example, as shown in FIG. 3.

Concretely to describe, a torque of the motor 22 in a test operation changes, for example, as a curve S11 shows in FIG. 3, and meanwhile a torque of the motor 22 in a regular operation changes, for example, as a curve

S12 shows in FIG. 3.

Therefore, in the case where, in a test operation, a torque limit value for the motor 22 at the time of moving up the end effector is expressed as a first torque limit value T1ll and a torque limit value for the motor 22 at the time of moving down the end effector is expressed as a second torque limit value T12; the first torque limit value T1ll and the second torque limit value T12 are specified in the control unit 5, in such a way that an absolute value of the second torque limit value T1l2 is smaller than an absolute value of the first torque limit value T1ll. In the same way, a torque limit value T13 and a torque limit value T1l4 are specified in the control unit 5, in such a way that an absolute value of the torque limit value T14 for the motor 22 at the time of moving down the end effector in a regular operation is smaller than an absolute value of the torque limit value T13 for the motor 22 at the time of moving up the end effector in a regular operation.

Then, in the test operation, the control unit 5 determines whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector; and furthermore, at the time of moving up the end effector in the test operation, the control unit 5 controls the motor 22 on the basis of the first torque limit value

T1ll, and meanwhile the control unit 5 controls the motor 22 on the basis of the second torque limit value

T12 at the time of moving down the end effector in the test operation. In the same way; in the regular operation, the control unit 5 determines whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector; and furthermore, at the time of moving up the end effector in the regular operation, the control unit 5 controls the motor 22 on the basis of the torque limit value T13, and meanwhile the control unit 5 controls the motor 22 on the basis

EE —————————— of the torque limit value T1l4 at the time of moving down the end effector in the regular operation. In the present embodiment, in the case of having determined that the motor 22 turns in a direction for moving up the end effector, the control unit 5 sets the torque limit values T1l1 and T13 as torque limit values for the motor 22. Meanwhile, in the case of having determined that the motor 22 turns in a direction for moving down the end effector, the control unit 5 sets the torque limit values T12 and T1l4 as torque limit values for the motor 22. In other words, the control unit 5 switches from/to the torque limit values T1ll and T13 to/from the torque limit values T1l2 and T14, as torque limit values for the motor 22, in accordance with a turning direction of the motor 22.

Incidentally, as described above; in the case where the motor 22 turns in one direction in a test operation, the motor 22 is controlled with reference to the first torque limit value T1l1l that is lower than the torque limit value T13 in the case of the motor 22 turning in the one direction in a regular operation; and then in the case where the motor 22 turns in the other direction in a test operation, the motor 22 is controlled with reference to the torque limit value T12 that is higher than the torque limit value T14 in the case of the motor 22 turning in the other direction in a regular operation. Moreover, even when the end effector being in stop condition is held at a predetermined position, the motor 22 needs to have a predetermined retaining torque T15, as FIG. 3 shows.

In the present embodiment, a difference between the first torque limit value T1ll and the retaining torque

T15 is nearly equal to a difference between the second torque limit value T12 and the retaining torque T15; and meanwhile a difference between the torque limit value T13 and the retaining torque T15 is nearly equal to a difference between the torque limit value T14 and the retaining torque T15. Moreover to describe, depending on values of the torque limit value T12 and the torque limit value T1l4, sometimes a torque of the motor 22 at the time just after a servo control starts is lower than the torque limit value T12 and the torque limit value T1l4. Therefore, within a predetermined time period just after a servo control on the motor 22 starts, the control unit 5 controls the motor 22 with reference to a torque limit value that is lower than the torque limit value T12 and the torque limit value

T14.

In the present embodiment, a weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like can be entered, as a motor load to be placed on the motor 22, by an operator by use of the pendant switch 6. If the weight load is entered by use of the pendant switch 6, the control unit 5 sets the torque limit values T1l1l through T1l4 on the basis of the entered weight load. Concretely to describe, torque limit values T11l through T14 corresponding to a weight load are listed in a table and saved in the control unit 5. Then, according to the entered weight load, the control unit 5 reads out and sets the corresponding torque limit values T1ll through T14. For example, the table shown in FIG. 4 is saved in the control unit 5, and the control unit 5 reads out and sets the corresponding torque limit a values T1l through T1l4, according to the entered weight load.

Incidentally, in an example shown in FIG. 4; a difference between the first torque limit value T1ll and the second torque limit value T12 is constant, being irrelevant to a weight load; and meanwhile, a difference between the torque limit value T13 and the torque limit value T14 is also constant, being irrelevant to a weight load. Nevertheless, the difference between the first torque limit value T1l1l and the second torque limit value T12, as well as the difference between the torque limit value T13 and the torque limit value T14 may become greater, as the weight load becomes greater.

Moreover, in the present embodiment, torque limit values for the motors 15, 17, and 19 are saved in the control unit 5, for example, as predetermined constant values. Alternatively, torque limit values for the motors 15, 17, and 19, corresponding to a weight load, may be listed in a table and saved in the control unit 5, in such a way that the control unit 5 reads out and sets the corresponding torque limit values, according to the weight load entered by use of the pendant switch 6. (Principal effect of the present embodiment)

As explained above, in the present embodiment; in a test operation, the control unit 5 individually turns the motors 15, 17, 19 and 22 at a revolution speed slower than a revolution speed for a regular operation.

In other words, the robot 1 in a test operation moves slowly, in the present embodiment. Therefore, according to the present embodiment, in the case where an operator becomes aware of a danger in a test operation, and triggers an emergency stop of the robot 1, it becomes possible to shorten an idle running distance of the robot 1.

Moreover, according to the present embodiment; in the case where the motors 15, 17, 19 and 22 turn in one direction in a test operation, the motors 15, 17, 19 and 22 are individually controlled with reference to a torque limit value lower than a torque limit value in the case of the motors 15, 17, 19 and 22 turning in the one direction in a regular operation; and meanwhile, in the case where the motors 15, 17, 19 and 22 turn in the other direction in a test operation, the motors 15, 17, 19 and 22 are individually controlled with reference to a torque limit value higher than a torque limit value in the case of the motors 15, 17, 19 and 22 turning in the other direction in a regular operation. Therefore, according to the present embodiment; in the case where the robot 1 touches a peripheral device and the like in a test operation, a torque of the motors 15, 17, 19 and 22 exceeds the torque limit value, or falls below the torque limit value, in a short time. Therefore, in accordance with the present embodiment; in the case where the robot 1 touches a peripheral device and the like in a test operation, it becomes possible to stop the motors 15, 17, 19 and 22 in a short time.

Thus, according to the present embodiment, in the case where an operator becomes aware of a danger in a test operation, and triggers an emergency stop of the robot 1, it becomes possible to shorten an idle running distance of the robot 1. Moreover, in the case where the robot 1 touches a peripheral device and the like in a test operation, it becomes possible to stop the motors 15, 17, 19 and 22 in a short time. Therefore, according to the present embodiment, it becomes possible to prevent the robot 1 from getting damaged in a test operation. Moreover, in the case where a malfunction happens in a test operation; by way of carrying out a predetermined procedure such as a re- teaching operation, it becomes possible to prevent the robot 1 from touching a peripheral device and the like in a regular operation after completion of the test operation, so as to prevent the robot 1 from getting damaged in the regular operation. As a result, according to the present embodiment, it becomes possible to prevent the robot 1 from getting damaged in an automatic operation after completion of the teaching operation.

In the present embodiment, the first torque limit value T1ll and the second torque limit value T1l2 are specified in such a way that an absolute value of the second torque limit value T1l2 is smaller than an absolute value of the first torque limit value T11.

Moreover in the present embodiment, the torque limit value T13 and the torque limit value T14 are specified in such a way that an absolute value of the torque limit value T1l4 is smaller than an absolute value of the torque limit value T13. Therefore, in the present embodiment, the torque limit values T1l1l through T1l4 can be specified in such a way that; a torque of the motor 22 does neither exceed the torque limit value T11l or

T13, nor fall below the torque limit value T12 or T14, when the end effector normally moves up and down; and on the other hand, in such a way that; the torque of a4 the motor 22 exceeds the torque limit value T1l1l or T13 if the end effector and the like touch a peripheral device and the like at a time when the end effector moves up, and also the torque of the motor 22 falls

Dbelow the torque limit value T12 or T1l4 if the end effector and the like touch a peripheral device and the like at a time when the end effector moves down.

Moreover, in the present embodiment; the motor 22 is controlled on the basis of the torque limit value

T11 or T13 when the end effector moves up, and on the other hand when the end effector moves down, the motor 22 is controlled on the basis of the second torque limit value T12 or T1l4; and then, the motor 22 stops if the torque of the motor 22 exceeds the torque limit value T1l1l or T13 at the time when the end effector moves up, or otherwise if the torque of the motor 22 falls below the second torque limit value T12 or T1l4 at the time when the end effector moves down.

Accordingly, in the present embodiment, even in the case where an absolute value of a torque required for the motor 22 at the time of moving up the end effector is greatly different from an absolute value of a torque required for the motor 22 at the time of moving down the end effector, owing to an impact of weight of the end effector, a workpiece held by the end effector, and the like; it becomes possible to prevent the end effector and the like from getting damaged, by way of stopping the motor 22, when the end effector and the like touch a peripheral device and the like at the time of moving up and down the end effector. Moreover, in the present embodiment; even in the case where an absolute value of a torque required for the motor 22 at the time of moving up the end effector is greatly different from an absolute value of a torque required for the motor 22 at the time of moving down the end effector, it becomes possible to appropriately move up and down the end effector, by way of keeping on turning the motor 22, when the end effector normally moves up and down.

In the present embodiment, a weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like can be entered, by use of the pendant switch 6. If the weight load is entered by use of the pendant switch 6, the control unit 5 sets the torque limit values T1l1l through T14 on the basis of the entered weight load. Therefore, in the present embodiment, the torque limit values T1l through T1l4 can be set in accordance with the weight load, in such a way that the end effector can be moved up and down more appropriately, and furthermore in such a way that the torque of the motor 22 exceeds the torque limit value T1ll or T1l3, or otherwise falls below the torque limit value T12 or T1l4, in the case where the end effector and the like touch a peripheral device and the like. Accordingly, in the present embodiment, the end effector can be moved up and down more appropriately, and furthermore it becomes possible to surely prevent the end effector and the like from getting damaged. (Other embodiments)

Though the embodiment described above is an example of a preferred embodiment according to the present invention, an embodiment of the present invention is not limited to the above embodiment, and various variations can be made without changing the concept of the present invention.

In the embodiment described above; in a test operation, the control unit 5 individually turns the motors 15, 17, 19 and 22 at a revolution speed slower than a revolution speed for a regular operation; and moreover, in the case where the motors 15, 17, 19 and 22 turn in the one direction in a test operation, the control unit 5 individually controls the motors 15, 17, 19 and 22 with reference to a torque limit value lower than a torque limit value in the case of the motors 15, 17, 19 and 22 turning in the one direction in a regular operation; and meanwhile, in the case where the motors 15, 17, 19 and 22 turn in the other direction in a test operation, the control unit 5 individually controls the motors 15, 17, 19 and 22 with reference to a torque limit value higher than a torque limit value in the case of the motors 15, 17, 19 and 22 turning in the other direction in a regular operation. Alternatively, for example, it may be possible that; in a test operation, the control unit 5 individually turns the motors 15, 17 and 19 at a revolution speed that is the same as a revolution speed for a regular operation, and moreover individually controls the motors with reference to a torque limit value that is the same as a torque limit value for a regular operation; and on the other hand, in the same manner as in the embodiment described above, in a test operation, the control unit 5 turns the motor 22 at a revolution speed slower than a revolution speed for a regular operation, and moreover, in the case where the motor 22 turns in the one direction in a test operation, the control unit 5 of a torque limit value of the moving up/down motor at the time of moving down the third arm, are usually specified with the same value.

For example, in the case where a torque of the moving up/down motor in a direction to move up the third arm is expressed as a plus torque, and a torque of the moving up/down motor in a direction to move the down third arm is expressed as a minus torque, an absolute value of a torque required for the moving up/down motor that rotates in one direction becomes large at the time of moving up the third arm; and in the meantime, an absolute value of a torque required for the moving up/down motor that rotates in the other direction becomes small at the time of moving down the third arm, as described above. Therefore, if an absolute value of a torque limit value is specified according to the torque of the moving up/down motor at the time of moving up the third arm, the torque of the moving up/down motor does not become less than the torque limit value, even though the end effector and the like are in touch with a peripheral device and so on when the third arm moves down; so that the moving up/down motor keeps on rotating and the end effector and the like are in danger of getting damaged. In the meantime, if an absolute value of a torque limit value is specified according to the torque of the moving up/down motor at the time of moving down the third arm, the torque of the moving up/down motor could exceed the torque limit value, even though the third arm normally moves up at the time when the third arm moves up; so that the moving up/down motor could be in danger of getting stopped.

controls the motor 22 with reference to the first torque limit value T1l; and meanwhile, in the case where the motor 22 turns in the other direction in a test operation, the control unit 5 controls the motor 22 with reference to the second torque limit value T12.

Owing to an impact of weight of the end effector, a workpiece held by the end effector, and the like; the end effector and the like at the time of moving down are likely to get damaged if they touch a peripheral device and the like. Nevertheless, in this case, it becomes possible to stop the motor 22 for moving up and down the end effector in a short time, when the end effector and the like touch a peripheral device and the like in a test operation; and moreover a moving distance of the end effector after stopping the motor 22 can be shortened. Accordingly, it becomes possible to prevent the end effector and the like from getting damaged in a test operation. Furthermore, in this case, the motors 15, 17 and 19 in a test operation individually turn at a revolution speed that is the same as a revolution speed for a regular operation, and therefore an operation speed of the robot 1 in the test operation can be increased.

In the embodiment described above, a revolution speed and a torque limit value for the motors 15, 17, 19 and 22 in a test operation may be selectable.

Namely, a revolution speed and a torque limit value for the motors 15, 17, 19 and 22 in a test operation may arbitrarily be specified by an operator. In this case, a revolution speed and a torque limit value for each of the motors 15, 17, 19 and 22 may be selectable.

Accordingly, in this case, it becomes possible to carry

HE EE ——————— ——————————————————————— ere out a test operation for the robot 1, with various combinations of a revolution speed and a torque limit value for the motors 15, 17, 19 and 22. Incidentally, in this case, it is also possible in a test operation to control at least one of the motors 15, 17, 19 and 22 with reference to a torque limit value that is the same as a torque limit value for a regular operation, while the motors 15, 17, 19 and 22 being turned at a revolution speed slower than a revolution speed for a regular operation.

In the embodiment described above, a weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like can be entered, by use of the pendant switch 6. If the weight load is entered by use of the pendant switch 6, the control unit 5 sets the torque limit values T1l through

Tl4 on the basis of the entered weight load.

Alternatively, for example, while a motor load being obtained by way of a motor load obtaining mode provided for automatically obtaining a motor load of the motor 22, the control unit 5 may set the torque limit values

T1l1l through T14, on the basis of the obtained motor load. In other words, while obtaining the motor load of the motor 22 by way of operating the motor 22, the control unit 5 may set the torque limit values T11l through T14, on the basis of the obtained motor load.

In this case, for example, an operation of the pendant switch 6 switches over to the motor load obtaining mode. Moreover, in the case where the weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like varies in a narrow range, the torque limit values T11l through

Tl4 may be stored as constant values in the control unit 5.

In the embodiment described above, the control unit 5 controls the motor 22, on the basis of the first torque limit value T11l, at the time of moving up the end effector in a test operation, and meanwhile controls the motor 22, on the basis of the second torque limit value T12 having an absolute value that is smaller than an absolute value of the first torque limit value T11l, at the time of moving down the end effector in a test operation. Alternatively, for example, the control unit 5 may control the motor 22, on the basis of the first torque limit value T1l1, at the time of moving up the end effector in a test operation, while controlling the motor 22, on the basis of a second torque limit value having an absolute value that is equal to the absolute value of the first torque limit value T11l, at the time of moving down the end effector in a test operation.

Similarly, although in the embodiment described above, the control unit 5 controls the motor 22, on the basis of the torque limit value T13, at the time of moving up the end effector in a regular operation, and meanwhile controls the motor 22, on the basis of the torque limit value T14 having an absolute value that is smaller than an absolute value of the torque limit value T13, at the time of moving down the end effector in a regular operation; the control unit 5 may control the motor 22, on the basis of the torque limit value

T13, at the time of moving up the end effector in a regular operation, while controlling the motor 22, on the basis of a torque limit value having an absolute value that is equal to the absolute value of the torque limit value T13, at the time of moving down the end effector in a regular operation.

In the embodiment described above; in the case of having determined that the motor 22 turns in a direction for moving up the end effector, the control unit 5 sets the torque limit values T1l1l and T13 as torque limit values for the motor 22; and meanwhile, in the case of having determined that the motor 22 turns in a direction for moving down the end effector, the control unit 5 sets the torque limit values T12 and T14 as torque limit values for the motor 22.

Alternatively, for example, without determining whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector, the control unit 5 may stop the motor 22 when a torque of the motor 22 exceeds the torque limit value T1l1l or T13, and when a torque of the motor 22 falls below the torque limit value T12 or

Tl4. In other words, the control unit 5 may not need to switch a torque limit value for the motor 22, to/from the torque limit value T1ll or T13 from/to the torque limit value T12 or T14, in accordance with a turning direction of the motor 22. Even in this case, the motor 22 is controlled on the basis of the torque limit value T11 or T13, at the time of moving up the end effector, and in the meantime, the motor 22 is controlled on the basis of the torque limit value T12 or Tl4, at the time of moving down the end effector.

Although, in the embodiment described above, the arm 3 is structured with two arm sections that are the first arm section 11 and the second arm section 12, the arm 3 may be structured with three or more arm ~ sections. (The second embodiment) (Torque control for the moving up/down motor)

FIG. 5 is a graph for explaining a torque limit value of the motor 22 shown in FIG. 1. FIG. 6 is a list for explaining an example of a table showing torque limit values stored in the control unit 5 illustrated in FIG. 1.

In order to prevent the robot 1 and the like from getting damaged by way of stopping the motors 15, 17, 19 and 22 (namely, stopping the operation of the robot 1) in the case where the robot 1 in motion touches a peripheral device and the like of the robot 1; torque limit values for the motors 15, 17, 19 and 22 are specified in the control unit 5. Then, if a torque of the motors 15, 17, 19 and 22 reaches its corresponding torque limit value, the control unit 5 stops the motors 15, 17, 19 and 22.

Even though a turning direction of the motors 15, 17 and 19 changes, an absolute value of a torque required for the motors 15, 17 and 19 does not change on a large scale owing to an impact of gravity force of the arm 3, the ball screw spline 4, and the like.

Therefore, in the present embodiment, an absolute value of a torque limit value for each of the motors 15, 17 and 19, in the case where the motors 15, 17 and 19 turn in a positive direction, is the same as an absolute value of a torque limit value for its corresponding one of the motors 15, 17 and 19 in the case where the motors 15, 17 and 19 turn in a reverse direction.

On the other hand, the motor 22 moves up and down the ball screw spline shaft 23 together with the end effector. Therefore, owing to an impact of weight of the ball screw spline shaft 23, the end effector, a workpiece held by the end effector, and the like; an absolute value of a torque required for the motor 22 at the time of moving up the end effector becomes great, and an absolute value of a torque required for the motor 22 at the time of moving down the end effector becomes small. Wherein a torque of the motor 22 in a direction to move up the end effector is defined as a plus torque, and a torque of the motor 22 in a direction to move down the end effector is defined as a minus torque; in the case where the end effector having stayed at a predetermined position moves up after a servo control starts and then the end effector moves down after being stopped for a predetermined time, a torque of the motor 22 changes, for example, as shown in FIG. 5. Concretely to describe, a torque of the motor 22 at the time of a teaching operation for the robot 1 changes, for example, as a curve S21 shows in

FIG. 5, and meanwhile a torque of the motor 22 in an automatic operation of the robot 1 after completion of : the teaching operation changes, for example, as a curve

S22 shows in FIG. 5. Namely, a maximum absolute value of a torque required for the motor 22 at the time of turning the motor 22 in one direction for moving up the end effector becomes greater than a maximum absolute value of a torque required for the motor 22 at the time of turning the motor 22 in the other direction for moving down the end effector.

RE EE — I ———————————————— eer == A

Therefore, wherein a torque limit value for the motor 22 at the time of moving up the end effector (namely, a torque limit value for the motor 22 turning in one direction for moving up the end effector) is expressed as a first torque limit value, and a torque limit value for the motor 22 at the time of moving down the end effector (namely, a torque limit value for the motor 22 turning in the other direction for moving down the end effector) is expressed as a second torque limit value; in the present embodiment, the first torque limit value and the second torque limit value are specified in the control unit 5, in such a way that an absolute value of the second torque limit value is smaller than an absolute value of the first torque limit value. Concretely to describe, a first torque limit value T21 and a second torque limit value T22 are specified in such a way that, at the time of a teaching operation for the robot 1, the absolute value of the second torque limit value T22 is smaller than the absolute value of the first torque limit value T21; and meanwhile, a first torque limit value T23 and a second torque limit value T24 are specified in such a way that, in an automatic operation (a regular operation) of the robot 1, the absolute value of the second torque limit value T24 is smaller than the absolute value of the first torque limit value T23 (refer to FIG. 5).

More specifically to describe, the first torque limit values T21 and T23 as well as the second torque limit values T22 and T24 are specified in such a way that; a torque of the motor 22 does neither exceed the first torque limit value T21 or T23, nor fall below the second torque limit value T22 or T24, when the end effector normally moves up and down; and furthermore, the torque of the motor 22 exceeds the first torque limit value T21 or T23 if the end effector and the like touch a peripheral device and the like at the time when the end effector moves up, and also the torque of the motor 22 falls below the second torque limit value T22 or T24 if the end effector and the like touch a peripheral device and the like at the time when the end effector moves down.

Moreover, the first torque limit value T21 in a teaching operation and the first torque limit value T23 in an automatic operation are different from each other, and meanwhile the second torque limit value T22 in a teaching operation and the second torque limit value T24 in an automatic operation are different from each other. Concretely to describe, as shown in FIG. 5, the first torque limit value T21 is smaller than the first torque limit value T23, and meanwhile the second torque limit value T22 is greater than the second torque limit value T24. Incidentally, even when the end effector being in stop condition is held at a predetermined position, the motor 22 needs to have a predetermined retaining torque T25, as FIG. 5 shows.

In the present embodiment, a difference between the first torque limit value T21 and the retaining torque

T25 is nearly equal to a difference between the second torque limit value T22 and the retaining torque T25; and meanwhile a difference between the the first torque limit value T23 and the retaining torque T25 is nearly equal to a difference between the second torque limit value T24 and the retaining torque T25.

EE ———————————————————————

Then, at the time of a teaching operation for the robot 1, the control unit 5 determines whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector; and furthermore, at the time of moving up the end effector in the teaching operation for the robot 1, the control unit 5 controls the motor 22 on the basis of the first torque limit value T21, and meanwhile the control unit 5 controls the motor 22 on the basis of the second torque limit value T22 at the time of moving down the end effector in the teaching operation for the robot 1. In other words, the control unit 5 stops the motor 22 in a teaching operation for the robot 1 if a torque of the motor 22 exceeds the first torque limit value T21 at the time when the end effector moves up, or otherwise if the torque of the motor 22 falls below the second torque limit value T22 at the time when the end effector moves down. Furthermore, in a teaching operation for the robot 1 according to the present embodiment, the control unit 5 specifies the first torque limit value T21 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving up the end effector, and specifies the second torque limit value

T22 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving down the end effector. In other words, the control unit 5 switches from/to the first torque limit value T21 to/from the second torque limit value T22, as the torque limit value for the motor 22, in accordance with a turning direction of the motor 22.

In the same way; in an automatic operation of the robot 1, the control unit 5 determines whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector; and furthermore, at the time of moving up the end effector in the automatic operation of the robot 1, the control unit 5 controls the motor 22 on the basis of the first torque limit value T23, and meanwhile the control unit 5 controls the motor 22 on the basis of the second torque limit value T24 at the time of moving down the end effector in the automatic operation of the robot 1. In other words, the control unit 5 stops the motor 22 in an automatic operation of the robot 1 if a torque of the motor 22 exceeds the first torque limit value T23 at the time when the end effector moves up, or otherwise if the torque of the motor 22 falls below the second torque limit value T24 at the time when the end effector moves down. Furthermore, in an automatic operation of the robot 1 according to the present embodiment, the control unit 5 specifies the first torque limit value T23 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving up the end effector, and specifies the second torque limit value

T24 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving down the end effector. In other words, the control unit 5 switches from/to the first torque limit value T23 to/from the second torque limit value T24, as the torque limit value for the motor 22, in accordance with a turning direction of the motor 22.

Thus, it is a first subject of the present invention to provide an industrial robot that can prevent itself from getting damaged in an automatic operation after a teaching operation finishes.

Moreover, the first subject of the present invention includes providing an industrial robot control method that enables prevention of damage in an automatic cperation after a teaching operation finishes.

Furthermore, it is a second subject of the present invention to provide an industrial robot that can prevent the industrial robot, a peripheral device, and the like from getting damaged, and moreover can carry out an appropriate operation, in the case of the industrial robot equipped with a motor for operation, for which a maximum absolute value of a torque required at the time of rotating in one direction is larger than a maximum absolute value of a torque required at the time of rotating in the other direction. Moreover, the second subject of the present invention includes providing a control method of an industrial robot that can prevent an industrial robot, a peripheral device, and the like from getting damaged, and moreover can carry out an appropriate operation of the industrial robot, in the case of the control method of the industrial robot equipped with a motor for operation, for which a maximum absolute value of a torque required at the time of rotating in one direction is larger than a maximum absolute value of a torque required at the time of rotating in the other direction.

Incidentally, depending on values of the second torque limit values T22 and the T24, sometimes a torque of the motor 22 at the time just after a servo control starts is lower than the second torque limit values T22 and the T24. Therefore, within a predetermined time period just after a servo control on the motor 22 starts, the control unit 5 controls the motor 22 with reference to a torque limit value that is lower than the second torque limit values T22 and the T24.

Moreover, a revolution speed of the motors 15, 17, 19 and 22 in a teaching operation for the robot 1 is slower than a revolution speed of the motors 15, 17, 19 and 22 in an automatic operation of the robot 1.

In the present embodiment, a weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like can be entered, as a motor load to be placed on the motor 22, by an operator by use of the pendant switch 6. If the weight load is entered by use of the pendant switch 6, the control unit 5 sets the first torque limit values T21 & T23, and the second torque limit values T22 & T24 on the basis of the entered weight load. Concretely to describe, first torque limit values T21 & T23, and second torque limit values T22 & T24 corresponding to a weight load are listed in a table and saved in the control unit 5. Then, according to the entered weight load, the control unit 5 reads out and sets the corresponding first torque limit values T21 & T23, and corresponding second torque limit values T22 & T24.

For example, the table shown in FIG. 6 is saved in the control unit 5, and the control unit 5 reads out and sets the corresponding first torque limit values T21 &

T23, and the corresponding second torque limit values

T22 & T24, according to the entered weight load.

Incidentally, in an example shown in FIG. 6; a difference between the first torque limit value T21 and the second torque limit value T22 is constant, being irrelevant to a weight load; and meanwhile, a difference between the first torque limit value T23 and the second torque limit value T24 is also constant, being irrelevant to a weight load. Nevertheless, the difference between the first torque limit value T21 and the second torque limit value T22, as well as the difference between the first torque limit value T23 and the second torque limit value T24 may become greater, as the weight load becomes greater. (Principal effect of the present embodiment)

As explained above, in the present embodiment; the first torque limit values T21 & T23 and the second torque limit values T22 & T24 are specified in such a way that; a torque of the motor 22 does neither exceed the first torque limit value T21 or T23, nor fall below the second torque limit value T22 or T24, when the end effector normally moves up and down; and furthermore, the torque of the motor 22 exceeds the first torque limit value T21 or T23 if the end effector and the like touch a peripheral device and the like at the time when the end effector moves up, and also the torque of the motor 22 falls below the second torque limit value T22 or T24 if the end effector and the like touch a peripheral device and the like at the time when the end effector moves down. Moreover, in the present embodiment; the motor 22 is controlled on the basis of the first torque limit value T21 or T23 when the end effector moves up (namely, when the motor 22 turns in the one direction for moving up the end effector), and on the other hand when the end effector moves down (namely, when the motor 22 turns in the other direction for moving down the end effector), the motor 22 is controlled on the basis of the second torque limit value T22 or T24; and then, the motor 22 stops if the torque of the motor 22 exceeds the first torque limit value T21 or T33 at the time when the end effector moves up, or otherwise if the torque of the motor 22 falls below the second torque limit value T22 or T24 at the time when the end effector moves down.

Therefore, in the present embodiment, it becomes possible to prevent the end effector and the like from getting damaged, by way of stopping the motor 22, in the case where the end effector and the like touch a peripheral device and the like at the time of moving up and down the end effector. Moreover, in the present embodiment, it becomes possible to appropriately move up and down the end effector, by way of keeping on turning the motor 22, when the end effector normally moves up and down. In other words, in the present embodiment; if a part of the robot 1 touches a peripheral device and the like while the motor 22 is turning, it becomes possible to prevent the robot 1, its peripheral device and the like from getting damaged, by way of stopping the motor 22; and in the meantime, when the motor 22 turns and the robot 1 normally operates, it becomes possible to make the robot 1 appropriately operate, by way of keeping on turning the motor 22.

In the present embodiment, a weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like can be entered, by use of the pendant switch 6. If the weight load is entered by use of the pendant switch 6, the control unit 5 sets the first torque limit values T21 & T23 and the second torque limit values T22 & T24, on the basis of the entered weight load. Therefore, in the present embodiment, the first torque limit values T21 & T23 and the second torque limit values T22 & T24 can be specified in accordance with the weight load, in such a way that the end effector can be moved up and down more appropriately, and furthermore the torque of the motor 22 exceeds the first torque limit value T21 or T23, or otherwise falls below the second torque limit value T22 or T24, in the case where the end effector and the like touch a peripheral device and the like. Accordingly, in the present embodiment, the end effector can be moved up and down more appropriately, and furthermore it becomes possible to surely prevent the end effector and the like from getting damaged.

In the present embodiment, the control unit 5 controls the motor 22 on the basis of the first torque limit value T21, at the time of moving up the end effector in a teaching operation for the robot 1; and meanwhile, controls the motor 22 on the basis of the second torque limit value T22, at the time of moving down the end effector in a teaching operation for the robot 1. Although, a teaching operation for the robot 1 through a manual operation by an operator creates a greater chance that the end effector and the like touch a peripheral device and the like, so as to make the end

EE ———pe eee rrr eee ____ effector and the like damaged, being compared to an automatic operation of the robot 1; it becomes possible in the present embodiment to prevent the end effector and the like from getting damaged even in such a teaching operation for the robot 1.

In the present embodiment, the first torque limit value T21 in a teaching operation for the robot 1 is smaller than the first torque limit value T23 in an automatic operation of the robot 1, and the second torque limit value T22 in a teaching operation for the robot 1 is greater than the second torque limit value

T24 in an automatic operation of the robot 1.

Therefore, in the present embodiment, a revolution speed of the motor 22 in an automatic operation of the robot 1 can be made faster than a revolution speed of the motor 22 in a teaching operation for the robot 1, as described above. Accordingly, in the present embodiment, a speed of moving the end effector up and down in an automatic operation of the robot 1 can be made faster. (Other embodiments)

In the embodiment described above, a weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like can be entered, by use of the pendant switch 6. If the weight load is entered by use of the pendant switch 6, the control unit 5 sets the first torque limit values T21 &

T23 and the second torque limit values T22 & T24, on the basis of the entered weight load. Alternatively, for example, while a motor load being obtained by way of a motor load obtaining mode provided for automatically obtaining a motor load of the motor 22, the control unit 5 may set the first torque limit values T21 & T23 and the second torque limit values T22 & T24, on the basis of the obtained motor load. In other words, while obtaining the motor load of the motor 22 by way of operating the motor 22, the control unit 5 may set the first torque limit values T21 & TZ23 and the second torque limit values T22 & T24, on the basis of the obtained motor load. In this case, for example, an operation of the pendant switch 6 switches over to the motor load obtaining mode. Moreover, in the case where the weight load including weight of the end effector, weight of a workpiece held by the end effector, and the like varies in a narrow range, the first torque limit values T21 & T23 and the second torque limit values T22 & T24 may be stored as constant values in the control unit 5.

In the embodiment described above, the control unit 5 controls the motor 22, on the basis of the first torque limit value T23, at the time of moving up the end effector in an automatic operation of the robot 1, and meanwhile controls the motor 22, on the basis of the second torque limit value T24 having an absolute value that is smaller than an absolute value of the first torque limit value T23, at the time of moving down the end effector in an automatic operation of the robot 1. Alternatively, for example, the control unit may control the motor 22, on the basis of the first torque limit value T23, at the time of moving up the end effector in an automatic operation of the robot 1, while controlling the motor 22, on the basis of a 5 second torque limit value having an absolute value that is equal to the absolute value of the first torque limit value T23, at the time of moving down the end effector in an automatic operation of the robot 1.

According to the embodiment described above; in a teaching operation for the robot 1, the control unit 5 specifies the first torque limit value T21 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving up the end effector, and specifies the second torque limit value T22 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving down the end effector. Alternatively, for example, without determining whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector, in a teaching operation for the robot 1, the control unit 5 may stop the motor 22 when a torque of the motor 22 exceeds the first torque limit value T21, and when a torque of the motor 22 falls below the second torque limit value T22. In other words, the control unit 5 may not need to switch over to/from the first torque limit value T21 from/to the second torque limit value

T22 as a torque limit value for the motor 22, in accordance with a turning direction of the motor 22, in a teaching operation for the robot 1. Even in this case, the motor 22 is controlled on the basis of the eee first torque limit value T21, at the time of moving up the end effector, and in the meantime, the motor 22 is controlled on the basis of the second torque limit value T22, at the time of moving down the end effector.

Similarly, according to the embodiment described above; in an automatic operation of robot 1, the control unit 5 specifies the first torque limit value

T23 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving up the end effector, and specifies the second torque limit value T24 as a torque limit value for the motor 22 in the case of having determined that the motor 22 turns in a direction for moving down the end effector. Nevertheless, without determining whether the motor 22 turns in a direction for moving up the end effector, or the motor 22 turns in a direction for moving down the end effector, the control unit 5 may stop the motor 22 when a torque of the motor 22 exceeds the first torque limit value T23, and when a torque of the motor 22 falls below the second torque limit value T24. In other words, the control unit 5 may not need to switch over to/from the first torque limit value T21 from/to the second torque limit value

T22 as a torque limit value for the motor 22, in accordance with a turning direction of the motor 22, in an automatic operation of the robot 1. Even in this case, the motor 22 is controlled on the basis of the first torque limit value T23, at the time of moving up the end effector, and in the meantime, the motor 22 is controlled on the basis of the second torque limit value T24, at the time of moving down the end effector.

Although, in the embodiment described above, the arm 3 is structured with two arm sections that are the first arm section 11 and the second arm section 12, the arm 3 may be structured with three or more arm sections. (Variation 1 of the industrial robot)

FIG. 7 is a plan view drawing of an industrial robot 1 according to another embodiment of the present invention. FIG. 8 is a side view drawing that shows the industrial robot 1, viewed along the arrows ‘E’ & ‘BE’ in FIG. 7. FIG. 9 is a side view drawing of an industrial robot 1 according to another embodiment of the present invention. FIG. 10 is a plan view for explaining a moving up/down mechanism of the industrial robot 1 shown in FIG. 9.

The industrial robot 1 to which the present invention is applied may be a Selective Compliance

Assembly Robot Arm for transferring a transfer object such as a glass substrate for a liquid crystal display, a semiconductor wafer and the like. For example, the robot 1 is a Selective Compliance Assembly Robot Arm for transferring a glass substrate 42 (hereinafter, called a ‘substrate 42’) for a liquid crystal display, as shown in FIG. 7 and FIG. 8. The robot 1 is installed in the atmosphere. Moreover, the robot 1 includes: two hands 43 as end effectors, on each of which the substrate 42 is placed; two arms 44 at each top end side of which the two hands 43 is individually connected; a main body 45 for supporting the two arms 44; and a base section 46 for supporting the main body 45 in such a way as to be movable in a horizontal direction. The main body 45 includes: arm supporting a I members 47 for individually supporting a root end side of each of the two arms 44; moving up/down members 48 to which arm supporting members 47 are individually fixed, and that are able to move vertically; a column member 49 for supporting the moving up/down members 48 in such a way as to be movable in a vertical direction; a base 50 that constructs a bottom end part of the main body 45, and that is horizontally movable with respect to the base section 46; and a turning member 51 to which a bottom end of the column member 49 is fixed, and that can turn with respect to the base 50.

The moving up/down members 48 are able to vertically move with respect to the column member 49, and the robot 1 is equipped with a moving up/down mechanism for moving the moving up/down members 48 up and down. The moving up/down mechanism includes: a moving up/down motor for moving each of the hands 43 up and down; a ball screw fixed to the column member 49 in such a way as to be rotatable, having its axis direction in a vertical direction, which rotates by drive power of the moving up/down motor; and a nut part that is engaged with the ball screw, and fixed to each of the moving up/down members 48. In the case of the robot 1 shown in FIG. 7 and FIG. 8, when the moving up/down motor turns in one direction, the hand 43, the arm 44, the arm supporting member 47, and the moving up/down member 48 move up; and on the other hand, when the moving up/down motor turns in the other direction, the hand 43, the arm 44, the arm supporting member 47, and the moving up/down member 48 move down. In the robot 1 shown in FIG. 7 and FIG. 8, the moving up/down motor is a motor for operation for operating the robot

[Means to Solve the Problems]

To bring a solution for the first subject described above, an industrial robot according to the present invention (a first invention) includes: a motor for operation; and a control unit for contrelling the motor; wherein, in the case where a torque of the motor for turning the motor in one direction is dealt with as a plus torque; and a torque of the motor for turning the motor in the other direction is dealt with as a minus torque; and an automatic operation of the industrial robot to be carried out, after completion of a teaching operation for the industrial robot, for checking whether a teaching point and/or a control program for the industrial robot are proper or not is dealt with as a test operation; and an automatic operation of the industrial robot to be carried out, after completion of the test operation, is dealt with as a regular operation; the control unit turns the motor in the test operation at a revolution speed slower than a revolution speed for the regular operation; and controls the motor, when the motor turns in the one direction in the test operation, with reference to a torque limit value lower than a torque limit value at a time when the motor turns in the one direction in the regular operation; and controls the motor, when the motor turns in the other direction in the test operation, with reference to a torque limit value higher than a torque limit value at a time when the motor turns in the other direction in the regular operation.

Furthermore, to bring a solution for the first subject described above, a control method of an

. \ ] 1. The moving up/down motor is connected to the control unit, which controls the moving up/down motor.

Incidentally, the arm 44 is an end effector fixing member to which the hand 43 as an end effector is fixed.

Also in the case of the robot 1 shown in FIG. 7 and FIG. 8, in the same way as the embodiment described above; the first torque limit values T21 & T23 and the second torque limit values T22 & T24 are specified in such a way that; the absolute values of the second torque limit values T22 & T24, which are torque limit values for the moving up/down motor at the time of moving down the hand 43, are smaller than the absolute values of the first torque limit values T21 & T23, which are torque limit values for the moving up/down motor at the time of moving up the hand 43. Then, at the time of moving up the hand 43, the moving up/down motor is controlled on the basis of the first torque limit value T21 or T23; and meanwhile at the time of moving down the hand 43, the moving up/down motor is controlled on the basis of the second torque limit value T22 or T24. Therefore, also in the case of the robot 1 shown in FIG. 7 and FIG. 8, the same effect can be obtained as in the embodiment described above.

Moreover, for example, the industrial robot 1 may be a Selective Compliance Assembly Robot Arm for transferring a semiconductor wafer 52 (hereinafter, called a ‘wafer 52’), as shown in FIG. 9 and FIG. 10.

The robot 1 is installed in the atmosphere. Moreover, the robot 1 includes: two hands 53 as end effectors, on each of which the wafer 52 is placed; two arms 54 at each top end side of which the two hands 53 are individually connected; and a main body 55 for supporting the two arms 54. The main body 55 includes: a base 56 and three frames 57, 58, and 59. The frame 57 is supported by the base 56 in such a way as to be movable upward and downward, and the frame 58 is supported by the base 57 in such a way as to be movable upward and downward, and meanwhile the frame 59 is supported by the base 58 in such a way as to be movable upward and downward. An arm supporting member 60 is fixed at a top end of the frame 59, and a root end side of each of the two arms 54 1s connected to the arm supporting member 60 in such a way as to be rotatable.

Then, the robot 1 has a moving up/down mechanism, in which a section of the three frames 57, 58, and 59 expands and contracts, in order to move the hands 53 and the arms 44 up and down, by way of moving up and down the frame 57 with respect to the base 56, moving up and down the frame 58 with respect to the frame 57, and moving up and down the frame 59 with respect to the frame 58. The moving up/down mechanism includes: a motor (moving up/down motor) 61 for moving the hands 53 up and down; a ball screw 62 fixed to the base 56 in such a way as to be rotatable, having its axis direction in a vertical direction, which rotates by drive power of the motor 61; and a nut part 63 that is engaged with the ball screw 62, and fixed to the frame 57; a movable pulley means 64 having a pulley and a belt, for connecting the frame 57 and the frame 58; and a movable pulley means 65 having a pulley and a belt, for connecting the frame 58 and the frame 59.

Moreover, in the moving up/down mechanism, a cylinder rod of a balancer cylinder 66 is fixed to the frame 57,

CD q and the frame 57 is always biased upward by the balancer cylinder 66.

In the case of the robot 1 shown in FIG. 9 and

FIG. 10; when the motor 61 turns in one direction, the frame 57 moves up, and the frames 58 and 59 move up by way of an action of the movable pulley means 64 and 65.

Contrarily, when the motor 61 turns in the other direction, the frame 57 moves down, and the frames 58 and 59 move down by way of an action of the movable pulley means 64 and 65. In other words, if the motor 61 turns in the one direction, the hands 53, the arms 54, the arm supporting member 60, and the frames 57, 58 and 59 move up. Contrarily, if the motor 61 turns in the other direction, the hands 53, the arms 54, the arm supporting member 60, and the frames 57, 58 and 59 move down. In the robot 1 shown in FIG. 9 and FIG. 10, the motor 61 is a motor for operation for operating the robot 1. The motor 61 is connected to the control unit, which controls the motor 61. Incidentally, the arm 54 is an end effector fixing member to which the hand 53 as an end effector is fixed.

Also in the case of the robot 1 shown in FIG. 9 and FIG. 10, in the same way as the embodiment described above; the first torque limit values T21 &

T23 and the second torque limit values T22 & T24 are specified in such a way that; the absolute values of the second torque limit values T22 & T24, which are torque limit values for the motor 61 at the time of moving down the hand 53, are smaller than the absolute values of the first torque limit values T21 & T23, which are torque limit values for the motor 61 at the time of moving up the hand 53. Then, at the time of

A : ‘ moving up the hand 53, the motor 61 is controlled on the basis of the first torque limit value T21 or T23; and meanwhile at the time of moving down the hand 53, the motor 61 is controlled on the basis of the second torque limit value T22 or T24. Therefore, also in the case of the robot 1 shown in FIG. 9 and FIG. 10, the same effect can be obtained as in the embodiment described above. (Variation 2 of the industrial robot)

FIG. 11 includes drawings of an industrial robot 1 according to another embodiment of the present invention, wherein FIG. 11A and FIG. 11B are a plan view drawing and a side view drawing, respectively.

Assembly Robot Arm for transferring a glass substrate for an organic EL (organic Electro-Luminescence) display in a vacuum. The robot 1 includes: a hand 73 as an end effector, on which a glass substrate is placed; an arm 74 at a top end side of which a hand 73 is connected; a main body 75 to which a root end side of the arm 74 is so connected as to be rotatable; and a moving up/down mechanism 76 for moving the main body 75 up and down. The main body 75 and the moving up/down mechanism 76 are housed in a case body 77 that is almost shaped like a cylinder having a bottom. The case body 77 is equipped with a flange part 77a shaped like a disk. The flange part 77a forms an upper end part of the case body 77. In the flange part 77a,

. . there is formed a through-hole in which an upper end side part of the main body 75 is positioned.

The hand 73 and the arm 74 are positioned at an upper side over the main body 75. Moreover, the hand 73 and the arm 74 are located at an upper side over the flange part 77a. A section of the robot 1, which is located higher than a lower end surface of the flange part 77a, is positioned in a vacuum chamber. In other words, the section of the robot 1, which is located higher than the lower end surface of the flange part 77a, is positioned in a vacuum region VR, and then the hand 73 and the arm 74 are located in a vacuum. On the other hand, a section of the robot 1, which is located lower than the lower end surface of the flange part 77a, is positioned in an atmospheric region AR (in the atmosphere).

In the main body 75, there is installed a motor 78 for rotating the arm 74 with respect to the main body 75. Moreover, the main body 75 includes: a hollow turning shaft 79 to which the root end side of the arm 74 is fixed; a speed reducer 80 for reducing a revolution speed of the motor 78 and transmitting the revolution to the arm 74; and a holding member 81 almost shaped like a cylinder which holds a case body of the speed reducer 80 and also holds the hollow turning shaft 79 so as to be rotatable. The hollow turning shaft 79 and the holding member 81 are placed in such a way that their axis directions and their vertical directions meet each other. The root end side of the arm 74 is fixed to an upper end of the hollow turning shaft 79.

.

At a joint part 82 for connecting the main body 75 and the arm 74 (namely, a joint part for connecting the hollow turning shaft 79 and the arm 74), there is placed a magnetic fluid sealing unit 83 that prevents air from flowing into the vacuum region VR. The magnetic fluid sealing unit 83 is placed between an outer circumference surface of the hollow turning shaft 79 and an inner circumference surface of the holding member 81. Moreover, at the joint part 82, there is placed a bellows 84 for preventing air from flowing into the vacuum region VR. The bellows 84 is placed inside the case body 77, so as to cover an outer “circumference side of a part of the holding member 81 at its upper end side. A lower end of the bellows 84 is fixed to the holding member 81, and an upper end of the bellows 84 is fixed to the flange part 77a. An inner circumference side of the bellows 84 is in a vacuum condition, and an outer circumference side of the bellows 84 is in an atmospheric condition. When a motor 86, to be described later, being included in the moving up/down mechanism 76 turns in order to move the main body 75 up and down, the bellows expands and contracts.

The moving up/down mechanism 76 includes: the motor 86 (moving up/down motor) for moving the main body 75 up and down; a ball screw 87 having its axis direction in a vertical direction, the ball screw 87 being fixed to the case body 77 so as to be rotatable, and being turned by drive power of the motor 86; and a nut part 88 that is engaged with the ball screw 87, and fixed to the main body 75. In the case of the robot 1 shown in FIG. 11 and FIG. 12, when the motor 86 turns in one direction, the hand 73, the arm 74, and the main body 75 move down; and on the other hand, when the motor 86 turns in the other direction, the hand 73, the arm 74, and the main body 75 move up. In the robot 1 shown in FIG. 11 and FIG. 12, the motor 86 is an motor for operation for operating the robot 1. The motor 86 is connected to the control unit, which controls the motor 86. Incidentally, the arm 74 is an end effector fixing member to which the hand 73 as an end effector is fixed. Moreover, in the case of the robot 1 shown in FIG. 11 and FIG. 12, the hollow turning shaft 79 and the holding member 81 constitute a shaft component to which the arm 74 as an end effector fixing member is fixed at an upper end of the shaft component. Even in the case where the main body 75 moves up, a lower end side of the shaft component is housed in the case body 77.

In the case of the robot 1 shown in FIG. 11 and

FIG. 12, the hand 73 and the arm 74 are located in a vacuum. Then, if the main body 75 moves down together with the hand 73 and the arm 74 in such a way as to expand the bellows 84, a negative pressure is generated to exert a great force so as to move upward the hand 73, the arm 74 and the main body 75. Therefore, an absolute value of a torque required for the motor 86 at the time of moving down the hand 73 becomes great, and meanwhile an absolute value of a torque required for the motor 86 at the time of moving up the hand 73 becomes small. In other words, a maximum absolute value of a torque required for the motor 86 at the time of turning the motor 86 in the one direction for moving down the hand 73 becomes greater than a maximum absolute value of a torque required for the motor 86 at the time of turning the motor 86 in the other direction for moving up the hand 73.

Therefore, in the case of the robot 1 shown in

FIG. 11 and FIG. 12; contrary to the embodiment described above, a first torque limit value and a second torque limit value are specified in such a way that; an absolute value of the second torque limit value as a torque limit value for the motor 86 at the time of moving up the hand 73 becomes smaller than an absolute value of the first torque limit value as a torque limit value for the motor 86 at the time of moving down the hand 73. Then, at the time of moving down the hand 73, the motor 86 is controlled on the basis of the first torque limit value; and meanwhile at the time of moving down the hand 73, the motor 86 is controlled on the basis of the second torque limit value. Therefore, also in the case of the robot 1 shown in FIG. 11 and FIG. 12, the same effect can be obtained as in the embodiment described above.

Incidentally, in the case of the robot 1 shown in

FIG. 11 and FIG. 12, the upper end of the bellows 84 may be fixed to an upper end side of the hollow turning shaft 79, while the lower end of the bellows 84 being fixed to the flange part 77a, in such a way that an inner circumference side of the bellows 84 is in an atmospheric condition, and an outer circumference side of the bellows 84 is in a vacuum condition. In this case, the bellows 84 is placed outside the case body 77, so as to cover an outer circumference side of a part of the hollow turning shaft 79 at its upper end side. Even in this case, if the main body 75 moves down together with the hand 73 and the arm 74 in such a way as to expand the bellows 84, a negative pressure is generated to exert a great force so as to move upward the hand 73, the arm 74 and the main body 75.

Therefore, a first torque limit value and a second torque limit value are specified in such a way that; an absolute value of the second torque limit value as a torque limit value for the motor 86 at the time of moving up the hand 73 becomes smaller than an absolute value of the first torque limit value as a torque limit value for the motor 86 at the time of moving down the hand 73. Then, at the time of moving down the hand 73, the motor 86 is controlled on the basis of the first torque limit value; and meanwhile at the time of moving down the hand 73, the motor 86 is controlled on the basis of the second torque limit value. (Variation 3 of the industrial robot)

FIG. 13 is a perspective view of a battery change system in which a robot 1 according to another embodiment of the present invention is placed. FIG. 14 is a perspective view showing a section ‘G’ of FIG. 13, viewed from another angle. FIG. 15 is a schematic view for explaining a structure of a battery 103 and a battery storage section 104 shown in FIG. 13. FIG. 16 is a drawing that shows a battery extracting/inserting mechanism 117 and a moving up/down mechanism 118 shown in FIG. 14, in a front elevation view. FIG. 17 is a drawing that shows the battery extracting/inserting mechanism 117 and the moving up/down mechanism 118, viewed along the line ‘H-H’ in FIG. 16. FIG. 18 is a drawing for explaining a battery transfer mechanism 125 shown in FIG. 16, in its side view. In the explanation

« . below, two directions being at right angles to each other in a horizontal direction are individually an X- direction and a Y-direction; wherein the X-direction is a front-and-back direction, and the Y-direction is a right-and-left direction.

A robot 1 to which the present invention is applied may be a battery change robot for changing a battery 103 installed in a vehicle 102. The vehicle 102 is, for example, an electric bus. The vehicle 102 is equipped with a battery storage section 104 in which a plurality of batteries 103 are stored. At the time of changing a battery 103, the vehicle 102 is stopped in such a way that a traveling direction of the vehicle 102 is nearly consistent with the right-and-left direction. The robot 1 faces a side surface 102a of the vehicle 102 in the front-and-back direction, in order to make it possible to change the battery 103 stored in the battery storage section 104. The robot 1 extracts the battery 103 stored in the battery storage section 104, and transfers the battery 103 into a buffer station that is not shown; and meanwhile, transfers out a battery 103, which is already electrically-charged and stored in the buffer station, from the buffer station, and then inserts the battery 103 into the battery storage section 104.

The battery storage section 104 is equipped with a battery table 106 on which the battery 103 is installed, as well as a side wall 107 at right and left sides, so that the battery table 106 and the side wall 107 make up a storage space for the battery 103. In the battery storage section 104, there are formed a plurality of storage spaces for the batteries 103, and industrial robot according to the present invention (the first invention) is a control method of an industrial robot including a motor for operation; wherein, in the case where a torque of the motor for turning the motor in one direction is dealt with as a plus torque; and a torque of the motor for turning the motor in the other direction is dealt with as a minus torque; and an automatic operation of the industrial robot to be carried out, after completion of a teaching operation for the industrial robot, for checking whether a teaching point and/or a control program for the industrial robot are proper or not is dealt with as a test operation; and an automatic operation of the industrial robot to be carried out, after completion of the test operation, is dealt with as a regular operation; in the test operation, the motor is turned at a revolution speed slower than a revolution speed for the regular operation; and when the motor turns in the one direction in the test operation, the motor is controlled with reference to a torque limit value lower than a torque limit value at the time when the motor turns in the one direction in the regular operation; and meanwhile, when the motor turns in the other direction in the test operation, the motor is controlled with reference to a torque limit value higher than a torque limit value at the time when the motor turns in the other direction in the regular operation.

According to the present invention, in the test operation that is an automatic operation to be carried out after completion of the teaching operation, for checking whether a teaching point and/or a control the plurality of batteries 103 can be stored there.

Moreover, the battery storage section 104 includes: a locking mechanisml09 for locking the battery 103 stored, and a connector 110 for electrically connecting the vehicle 102 and the battery 103, as shown in FIG. 15. The locking mechanisml09 includes; a locking member 111 and a biasing member 112. The connector 110 is positioned at a rear side of the battery storage section 104.

The locking member 111 is held by the side wall 107, for example, in such a way as to be movable in the right-and-left direction. The locking member 111 is biased inward in the right-and-left direction, by a biasing member that is not shown; and the locking member 111 protrudes inward from the side wall the side wall 107 in the battery storage section 104. Moreover, the locking member 111 is shaped, for example, to be nearly a triangle pole; and the locking member 111 includes a sloping surface 1lla that is sloped with respect to a plane configured with the front-and-back direction and a vertical direction, and an end surface 111b that is in parallel with a plane configured with the right-and-left direction and the vertical direction. The end surface 11l1lb constitutes an end surface at a rear side of the locking member 111. The sloping surface 1llla is so sloped as to be more widened outward in the right-and-left direction at a position, as the position is located further in a direction toward a front side of the battery storage section 104.

The biasing member 112 is, for example, a compression coil spring. The biasing member 112 has a function in biasing the battery 103 toward the front side of the battery storage section 104, in such a way that an end surface 115b of a latching protrusion 115 to be described later, which is formed in the battery 103, and the end surface 111lb of the locking member 111 contact each other with a predetermined contact pressure. In the vehicle 102, by biasing the battery 103 with the biasing member 112, a vibration of the battery 103 being stored in the battery storage section 104 is controlled during running time of the vehicle 102.

At a front side surface of the battery 103, there is formed a handle 114 for extracting the battery 103 from the battery storage section 104. Moreover, as shown in FIG. 15, the battery 103 includes a latching protrusion 115 that is engaged with the locking member 111, and a connector 116 to be connected to the connector 110. The connector 116 is fixed at a rear end surface (a rear side surface) of the battery 103 to be stored in the battery storage section 104.

The latching protrusion 115 is fixed, for example, to each of right-and-left side surfaces of the battery 103, so as to protrude outward in the right-and-left direction, from the right-and-left side surfaces of the battery 103. The latching protrusion 115 is shaped, for example, to be nearly a triangle pole; and the latching protrusion 115 includes a sloping surface 115a that is sloped with respect to a plane configured with the front-and-back direction and a vertical direction, and an end surface 115b that is in parallel with a plane configured with the right-and-left direction and the vertical direction. The end surface 115b constitutes an end surface at a front side of the latching protrusion 115. The sloping surface 115a is so sloped as to be more widened outward in the right- and-left direction at a position, as the position is located further in a direction toward a front side of the battery storage section 104.

When the battery 103 is inserted into the battery storage section 104 at the time of storing the battery 103 into the battery storage section 104, the sloping surface 115a of the latching protrusion 115 and the sloping surface 1l1la of the locking member 111 contact with each other in due time. Then, out of the state, if the battery 103 is further inserted into the battery storage section 104, the locking member 111 moves outward in the right-and-left direction, against a biasing force by the biasing member that biases the locking member 111, as FIG. 15B shows. If the battery 103 is still further inserted until the latching protrusion 115 passes the locking member 111, the locking member 111 moves inward in the right-and-left direction with the biasing force by the biasing member.

Then, if the battery 103 is moreover inserted until the latching protrusion 115 passes the locking member 111, the biasing member 112 contacts with a rear end surface of the battery 103 to bias the battery 103 toward a front side of the battery storage section 104.

Eventually, as shown in FIG. 15C, the end surface 115b of the latching protrusion 115 formed on the battery 103 and the end surface 111lb of the locking member 111 contact each other with a predetermined contact pressure, so as to lock the battery 103 stored in the battery storage section 104. As described above, the locking mechanisml09 is a mechanical locking

—_—_—_—_ mr mechanism for locking the battery 103; wherein the locking mechanism 109 operates by way of a force for inserting the battery 103 into the battery storage section 104. Concretely to describe, the locking mechanism 109 is a mechanical locking mechanism for locking the battery 103; wherein the locking mechanism 109 operates by way of a force for inserting the battery 103 into the battery storage section 104, by a battery connecting unit 124 included in the robot 1, to be described later. Moreover, the connector 110 and the connector 116 are connected by way of the force for inserting the battery 103 into the battery storage section 104. Concretely to describe, the connector 110 and the connector 116 are connected by way of the force for inserting the battery 103 into the battery storage section 104, by the battery connecting unit 124 to be described later.

Incidentally, the locking mechanisml09 is configured in such a way that; in the state shown in

FIG. 15C (namely, the state in which the battery 103 is locked by the locking mechanisml09), if the battery 103 is pressed furthermore a little toward the rear side of the battery storage section 104, the locking member 111 moves back so as to undo the contact condition of the end surface 115b and the end surface 111lb. Therefore, in the state of the battery 103 being locked by the locking mechanisml09, if the battery 103 is pressed furthermore a little toward the rear side of the battery storage section 104, the state of the battery 103 being locked by the locking mechanisml109 is undone so that it becomes possible to extract the battery 103 from the battery storage section 104.

The robot 1 includes: the battery extracting/inserting mechanism 117 for extracting the battery 103 from the battery storage section 104 and inserting the battery 103 into the battery storage section 104; the moving up/down mechanism 118 for moving up and down the battery extracting/inserting mechanism 117; a rotary mechanism 119 with its axis direction in a vertical direction, for rotating the battery extracting/inserting mechanism 117 and the moving up/down mechanism 118; and a horizontally moving mechanism 120 for moving the battery extracting/inserting mechanism 117, the moving up/down mechanism 118, and the rotary mechanism 119 in the right-and-left direction.

The battery extracting/inserting mechanism 117 includes: a battery mounting mechanism 123 having a battery mounting areal22 where the battery 103 is mounted at the time of extracting and inserting the battery 103; and a battery moving mechanism 125 having a battery engaging unit 124 for moving the battery 103 on the battery mounting areal22 while engaging with the battery 103 at the time of extracting and inserting the battery 103. Then, the battery extracting/inserting mechanism 117 is supported by a supporting memberl26.

The battery mounting mechanism 123 is equipped with a mounting area moving mechanism for moving the battery mounting areal22 in a direction for approaching the vehicle 102 and also a direction for getting away from the vehicle 102. The battery mounting areal22 moves in the direction for approaching the vehicle 102, at the time of changing the battery 103; and while no battery

103 is changed, the mounting areal22 stands by at a position away from the vehicle 102.

The battery moving mechanism 125 includes: an engaging unit moving mechanism 139 for moving the battery engaging unit 124 in the direction for approaching the vehicle 102 and the direction for getting away from the vehicle 102; and a movable supporting member 140 for supporting the battery engaging unit 124 so as to be movable, while being supported by the supporting memberl26 so as to be movable. In the meantime, the battery engaging unit 124 has an engaging claw part 141 for engaging with the handle 114 of the battery 103, and an air cylinder 142 for moving up and down the engaging claw part 141.

The movable supporting member 140 is so formed as to be a long and thin beam, in a moving direction of the battery engaging unit 124. As a structure for moving the battery engaging unit 124 and the movable supporting member 140, the engaging unit moving mechanism 139 includes: a motor 144, a ball screw 145, a nut part 146 to be engaged with the ball screw 145, pulleys 147 and 148, and a belt 149 to be installed across between the pulleys 147 and 148. The motor 144 is fixed to a rear end part of the supporting memberl26. The ball screw 145 is so held as to be rotatable by an upper surface part of the supporting memberl26, and the ball screw 145 rotates by drive power of the motor 144. The nut part 146 is fixed to a rear end part of the movable supporting member 140.

The pulley 147 is so held as to be rotatable by the rear end part of the movable supporting member 140; and meanwhile, the pulley 148 is so held as to be rotatable by a front end part of the movable supporting member 140. Then, the belt 149 is fixed to the battery engaging unit 124 by way of a belt fixing member 154; and also fixed to the upper surface part of the supporting memberl26 by way of a belt fixing member 155.

In the case of the robot 1 shown in FIG. 14 and the like, when the motor 144 turns, the battery engaging unit 124 linearly moves. Concretely to describe, when the motor 144 turns in one direction, the battery engaging unit 124 moves in a direction for approaching the vehicle 102; and in the meantime, when the motor 144 turns in the other direction, the battery engaging unit 124 moves in a direction for getting away from the vehicle 102. Therefore, in the case of the robot 1 shown in FIG. 14 and the like; when the motor 144 turns in the one direction, the battery engaging unit 124 inserts the battery 103 into the battery storage section 104; and in the meantime, when the 200 motor 144 turns in the other direction, the battery engaging unit 124 extracts the battery 103 from the battery storage section 104. In the case of the robot 1 shown in FIG. 14 and the like, the motor 144 is an extracting/inserting motor for moving the battery engaging unit 124, and also functions as a motor for operation for operating the robot 1. The motor 144 is connected to the control unit, which controls the motor 144.

In the case of the robot 1 shown in FIG. 14 and the like, at the time of inserting the battery 103 into the battery storage section 104, it is needed to move the locking member 111, being biased inward in the right-and-left direction by a biasing member, outward in the right-and-left direction; and moreover, the biasing member 112 contacts with a rear end surface of the battery 103 to bias the battery 103 toward a front side of the battery storage section 104. Therefore, in the case of the robot 1, an absolute value of a torque required for the motor 144, at a time when the battery engaging unit 124 inserts the battery 103 into the battery storage section 104, becomes great; and meanwhile an absolute value of a torque required for the motor 144 at a time when the battery engaging unit 124 extracts the battery 103 from the battery storage section 104, becomes small. In other words, a maximum absolute value of a torque required for the motor 144, at a time when the motor 144 turns in the one direction for inserting the battery 103, becomes greater than a maximum absolute value of a torque required for the motor 144, at a time when the motor 144 turns in the other direction for extracting the battery 103.

Therefore, in the case of the robot 1 shown in

FIG. 14 and the like; a first torque limit value and a second torque limit value are specified in such a way that; an absolute value of the second torque limit value as a torque limit value for the motor 144 at the time of extracting the battery 103 becomes smaller than an absolute value of the first torque limit value as a torque limit value for the motor 144 at the time of inserting the battery 103. Concretely to describe, the first torque limit value and the second torque limit value are specified in such a way that; a torque of the motor 144 does neither exceed the first torque limit value, nor fall below the second torque limit value,

when the battery engaging unit 124 normally carries out an extracting motion or an inserting motion on the battery 103; and furthermore, the torque of the motor 144 exceeds the first torque limit value if the battery 103, the battery engaging unit 124 and the like touch a peripheral device and the like at the time of inserting the battery 103, and also the torque of the motor 144 falls below the second torque limit value if the battery 103, the battery engaging unit 124 and the like touch a peripheral device and the like at the time of extracting the battery 103. Then, at the time of inserting the battery 103, the motor 144 is controlled on the basis of the first torque limit value; and meanwhile at the time of extracting the battery 103, the motor 144 is controlled on the basis of the second torque limit value.

Therefore, in the case of this robot 1; when the battery engaging unit 124 and the like touch a peripheral device and the like at the time of changing the battery 103 so that the torque of the motor 144 exceeds or falls below a torque limit value, it becomes possible to stop the motor 144 for preventing the battery engaging unit 124 and the like from getting damaged. Moreover, in the case of this robot 1; when the battery engaging unit 124 normally operates at the time of changing the battery 103, it becomes possible to appropriately operate the battery engaging unit 124 by way of keeping on turning the motor 144. (Variation 4 of the industrial robot)

FIG. 19 is a perspective view of an industrial robot 1 according to another embodiment of the present invention. FIG. 20 is a perspective view of an industrial robot 1 according to still another embodiment of the present invention.

A robot 1 to which the present invention is applied may be a robot other than a Selective

Compliance Assembly Robot Arm and a battery change robot. For example, a robot 1 to which the present invention is applied may be a vertical articulated robot having a plurality of joist parts, as shown in

FIG. 19. The robot 1 includes: a base frame 202 fixed to a predetermined installation surface; a rotary frame 203 connected to the base frame 202 in such a way as to be rotatable; a first arm 204 connected to the rotary frame 203 in such a way as to be rotatable; a second arm 205 connected to the first arm 204 in such a way as to be rotatable; and a wrist part 206 connected to the second arm 205 in such a way as to be rotatable.

A root end side of the first arm 204 is connected to the rotary frame 203 in such a way as to be rotatable around an axis Al as a center. At a joint part 213 connecting the rotary frame 203 and the first arm 204, there is placed a motor 214 for rotating the first arm 204 with respect to the rotary frame 203. A root end side of the second arm 205 is connected to a top end side of the first arm 204 in such a way as to be rotatable around an axis A2 as a center. At a joint part 215 connecting the first arm 204 and the second arm 205, there is placed a motor 216 for rotating the second arm 205 with respect to the first arm 204. In the following explanation, a clockwise turning direction in FIG. 19 is expressed as a clockwise direction, and counterclockwise turning direction in

FIG. 19 is expressed as a counterclockwise direction.

program for the industrial robot are proper or not, the motor is turned at a revolution speed slower than a revolution speed for the regular operation to be carried out, after completion of the test operation.

In other words, according to the present invention, an operation speed of the industrial robot is slow in the test operation. Therefore, according to the present invention, in the case where an operator becomes aware of a danger in a test operation, and triggers an emergency stop of the industrial robot, it becomes possible to shorten an idle running distance of the industrial robot.

Moreover, according to the present invention; when the motor turns in the one direction in the test operation, the motor is controlled with reference to a torque limit value lower than a torque limit value at the time when the motor turns in the one direction in the regular operation; and meanwhile, when the motor turns in the other direction in the test operation, the motor is controlled with reference to a torque limit value higher than a torque limit value at the time when the motor turns in the other direction in the regular operation. Therefore, according to the present invention; in the case where the industrial robot touches a peripheral device and the like in a test operation, a torque of the motor exceeds the torque limit value, or falls below the torque limit value, in a short time. Then, in accordance with the present invention; in the case where the industrial robot touches a peripheral device and the like in a test operation, it becomes possible to stop the motor in a short time, by way of stopping the motor immediately if

In the case where the robot 1 is used in such a way that; the first arm 204 rotates in a range where; a maximum absolute value of a torque required for the motor 214, at a time when the first arm 204 rotates clockwise with respect to the rotary frame 203, is greater than a maximum absolute value of a torque required for the motor 214, at a time when the first arm 204 rotates counterclockwise with respect to the rotary frame 203; owing to an impact of gravity force of the second arm 205, the wrist part 206, and the like, a first torque limit value and a second torque limit value are specified in such a way that; an absolute value of the second torque limit value as a torque limit value for the motor 214 at the time when the first arm 204 rotates counterclockwise is smaller than an absolute value of the first torque limit value as a torque limit value for the motor 214 at the time when the first arm 204 rotates clockwise. Then, at the time when the first arm 204 rotates clockwise, the motor 214 is controlled on the basis of the first torque limit value; and meanwhile at the time when the first arm 204 rotates counterclockwise, the motor 214 is controlled on the basis of the second torque limit value.

In the case where the robot 1 is used in such a way that; the second arm 205 rotates in a range where; a maximum absolute value of a torque required for the motor 216, at a time when the second arm 205 rotates clockwise with respect to the first arm 204, is greater than a maximum absolute value of a torque required for the motor 216, at a time when the second arm 205 rotates counterclockwise with respect to the first arm

204; owing to an impact of gravity force of the wrist part 206, and the like, a first torque limit value and a second torque limit value are specified in such a way that; an absolute value of the second torque limit value as a torque limit value for the motor 216 at the time when the second arm 205 rotates counterclockwise is smaller than an absolute value of the first torque limit value as a torque limit value for the motor 216 at the time when the second arm 205 rotates clockwise.

Then, at the time when the second arm 205 rotates clockwise, the motor 216 is controlled on the basis of the first torque limit value; and meanwhile at the time when the second arm 205 rotates counterclockwise, the motor 216 is controlled on the basis of the second torque limit value.

Even in this case, in the same way as the embodiments described above; if the wrist part 206, and the like touch a peripheral device and the like while the first arm 204 and the second arm 205 are in action, it becomes possible to prevent the wrist part 206, and the like from getting damaged, by way of stopping the motors 214 and 216; and in the meantime, when the first arm 204 and the second arm 205 are normally in action, it becomes possible to make the robot 1 appropriately operate, by way of keeping on turning the motors 214 and 216. Incidentally, in the robot 1 shown in FIG. 19, the motors 214 and 216 are motors for operation.

The motors 214 and 216 are connected to the control unit, which controls the motors 214 and 216.

Moreover, a robot 1 to which the present invention is applied may be a so-called parallel-link robot as shown in FIG. 20. The robot 1 includes: a main body

252, three levers 253 connected to the main body 252, arm parts 254 connected individually to the three levers 253, and a head unit 255 connected to the arm parts 254. The three levers 253 are connected to the main body 252 in such a manner as to stretch almost radially in an outer circumference direction of the main body 252, at nearly-equal angular intervals. Each root end side of the three levers 253 is connected to the main body 252 so as to be rotatable. At a joint part 257 connecting the main body 252 and each of the levers 253, there is placed a motor 258 for rotating the lever 253. Each root end side of the arm parts 254 is connected to a top end side of the corresponding lever 253 so as to be rotatable. The head unit 255 is connected to a top end side of the arm parts 254 so as to be rotatable.

In the case of the robot 1 shown in FIG. 20, when the robot 1 is used in such a way that; the lever 253 rotates in a range where; a maximum absolute value of a torque required for the motor 258, at a time when the lever 253 rotates in one direction, is greater than a maximum absolute value of a torque required for the motor 258, at a time when the lever 253 rotates in the other direction; owing to an impact of gravity force of the head unit 255, and the like, a first torque limit value and a second torque limit value are specified in such a way that; an absolute value of the second torque limit value as a torque limit value for the motor 258 at the time when the lever 253 rotates in the other direction is smaller than an absolute value of the first torque limit value as a torque limit value for the motor 258 at the time when the lever 253 rotates in the one direction. Then, at the time the lever 253 rotates in the one direction, the motor 258 is controlled on the basis of the first torque limit value; and meanwhile at the time when the lever 253 rotates in the other direction, the motor 258 is controlled on the basis of the second torque limit value.

Even in this case, in the same way as the embodiments described above; if the head unit 255, and the like touch a peripheral device and the like while the lever 253 and the arm parts 254 are in action, it becomes possible to prevent the head unit 255, and the like from getting damaged, by way of stopping the motor 258; and in the meantime, when the lever 253 and the arm parts 254 are normally in action, it becomes possible to make the robot 1 appropriately operate, by way of keeping on turning the 258. Incidentally, in the robot 1 shown in FIG. 20, the motor 258 is a motor for operation. The motor 258 is connected to the control unit, which controls the motor 258.

Furthermore, a robot to which the present invention is applied may be another type of robot. For example, a robot to which the present invention is applied may be a Cartesian Coordinate Robot system. [Reference Numerals] 1. robot (industrial robot) 2. main body 5. control unit 6. pendant switch 11. first arm section 12. second arm section

15. motor (first rotating motor) 17. motor (second rotating motor) 19. motor (turning motor) 22, 61, and 86. motor (moving up/down motor) 23. ball screw spline shaft (end effector fixing member) 43, 53, and 73. hand (end effector) 44, 54, and 74. arm (end effector fixing member) 77. case body 79. hollow turning shaft (part of shaft component) 81. holding member (part of shaft component) 84. bellows 102. vehicle 103. battery 104. battery storage section 117. battery extracting/inserting mechanism 124. battery engaging unit 144. motor (extracting/inserting motor) 214, 216, and 258. motor

T1 through T4, T13, and Tl4. torque limit value

Tll. first torque limit value (torque limit value)

T12. second torque limit value (torque limit value)

T21. first torque limit value: first torque limit value in teaching operation

T22. second torque limit value: second torque limit value in teaching operation

T23. first torque limit value: first torque limit value in automatic operation

T24. second torque limit value: second torque limit value in automatic operation

Claims

7. A control method of an industrial robot including a motor for operation; wherein, in the case where a torque of the motor for turning the motor in one direction is dealt with as a plus torque; and a torque of the motor for turning the motor in the other direction is dealt with as a minus torque; and an automatic operation of the industrial robot to be carried out, after completion of a teaching operation for the industrial robot, for checking whether a teaching point and/or a control program for the industrial robot are proper or not is dealt with as a test operation; and an automatic operation of the industrial robot to be carried out, after completion of the test operation, is dealt with as a regular operation; in the test operation, the motor is turned at a revolution speed slower than a revolution speed for the regular operation; and the motor is a moving up/down motor for moving up and down an end effector; and when the motor turns in the one direction, the end effector moves up; and when the motor turns in the other direction, the end effector moves down; and the first torque limit value is a torque limit value for the up/down motor at the time of moving up the end effector, and meanwhile the second torque limit value is a torque limit value for the up/down motor at the time of moving down the end effector; and the control unit controls the motor, on the basis of the first torque limit value, at a time when the end effector moves up; and controls the moving up/down motor, on the basis of the second torque limit value,

EE E——— EE ——— EE —— eer : ‘ ' “ What is claimed is:

1. An industrial robot, comprising: a motor for operation; and a control unit for controlling the motor; wherein, in the case where a torque of the motor for turning the motor in one direction is dealt with as a plus torque; and a torque of the motor for turning the motor in the other direction is dealt with as a minus torque; and an automatic operation of the industrial robot to be carried out, after completion of a teaching operation for the industrial robot, for checking whether a teaching point and/or a control program for the industrial robot are proper or not is dealt with as a test operation; and an automatic operation of the industrial robot to be carried out, after completion of the test operation, is dealt with as a regular operation; the control unit turns the motor in the test operation at a revolution speed slower than a revolution speed for the regular operation; and controls the motor, when the motor turns in the one direction in the test operation, with reference to a torque limit value lower than a torque limit value at a time when the motor turns in the one direction in the regular operation; and controls the motor, when the motor turns in the other direction in the test operation, with reference to a torque limit value higher than a torque limit value at a time when the motor turns in the other direction in the regular operation,

. . wherein, the industrial robot includes a moving up/down motor, as the motor for moving up and down an end effector; and in the case where a torque limit value for the moving up/down motor at a time when the end effector moves up in the test operation is dealt with as a first torque limit value; and a torque limit value for the moving up/down motor at a time when the end effector moves down is dealt with as a second torque limit value; the first torque limit value and the second torque limit value are specified in the control unit, in such a way that an absolute value of the second torque limit value is smaller than an absolute value of the first : 15 torque limit value; and the control unit controls the moving up/down motor, on the basis of the first torque limit value, at the time when the end effector moves up in the test operation; and controls the moving up/down motor, on the basis of the second torque limit value, at the time when the end effector moves down in the test operation.
2. The industrial robot according to claim 1: wherein, a revolution speed and a torque limit value for the motor in the test operation are selectable in the control unit.
3. The industrial robot according to claim 1: wherein, the industrial robot includes a pendant switch electrically connected to the control unit; and a motor load containing at least one of weight of the end effector and weight of a workpiece held by the end effector can be entered by use of the pendant switch; and the control unit sets the first torque limit value and the second torque limit value, on the basis of the motor load to be entered by use of the pendant switch.
4. The industrial robot according to claim 1: wherein, the industrial robot includes: a main body; a first arm section whose root end side is connected to the main body so as to be rotatable; a second arm section whose root end side is connected to a top end side of the first arm section so as to be rotatable; and an end effector located at a top end side of the second arm section; and the industrial robot furthermore includes, as the motor, a first rotating motor for rotating the first arm section with respect to the main body; a second rotating motor for rotating the second arm section with respect to the first arm section; a turning motor for turning the end effector with respect to the second arm section; and a moving up/down motor for moving the end effector up and down with respect to the second arm section.
5. An industrial robot, comprising: a motor for operation; and a control unit for controlling the motor; wherein, in the case where a torque of the motor for turning the motor in one direction is dealt with as a plus torque; and a torque of the motor for turning the motor in the other direction is dealt with as a minus torque; and an automatic operation of the industrial robot to be carried out, after completion of a teaching operation for the industrial robot, for checking whether a teaching point and/or a control program for the industrial robot are proper or not is dealt with as a test operation; and an automatic operation of the industrial robot to be carried out, after completion of the test operation, is dealt with as a regular operation;

the control unit turns the motor in the test operation at a revolution speed slower than a revolution speed for the regular operation; and controls the motor, when the motor turns in the one direction in the test operation, with reference to a torque limit value lower than a torque limit value at a time when the motor turns in the one direction in the regular operation; and controls the motor, when the motor turns in the other direction in the test operation, with reference to a torque limit value higher than a torque limit value at a time when the motor turns in the other direction in the regular operation,

wherein, the industrial robot includes: a main body; a first arm section whose root end side is connected to the main body so as to be rotatable; a second arm section whose root end side is connected to a top end side of the first arm section so as to be rotatable; an end effector located at a top end side of the second arm section; a first rotating motor for rotating the first arm section with respect to the main body; a second rotating motor for rotating the second arm section with respect to the first arm section; and

EE ——————————————————————————————————— ee eee = a turning motor for turning the end effector with respect to the second arm section; and the industrial robot includes a moving up/down motor, as the motor, for moving the end effector up and down with respect to the second arm section; and in the test operation, the control unit individually turns the first rotating motor, the second rotating motor, and the turning motor at a revolution speed that is the same as a revolution speed for the regular operation; and individually controls the motors with reference to a torque limit value that is the same as a torque limit value for the regular operation; and in the test operation, the control unit turns the moving up/down motor at a revolution speed slower than a revolution speed for the regular operation; and in the case where the moving up/down motor turns in one direction in the test operation, the control unit controls the moving up/down motor with reference to a torque limit value lower than a torque limit value in the case of turning the moving up/down motor in the one direction in the regular operation; and in the case where the moving up/down motor turns in the other direction in the test operation, the control unit controls the moving up/down motor with reference to a torque limit value higher than a torque limit value in the case of turning the moving up/down motor in the other direction in the regular operation.
6. The industrial robot according to claim 5: wherein, a revolution speed and a torque limit value for the motor in the test operation are selectable in the control unit.