JPH10202572A - Robot device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot device in which a wrist mechanism performing various kinds of works is capable of performing translation and rotary motion in a plane and easily performing an origin location adjustment. SOLUTION: When a movable body 5 provided with a hand 6 is made to be supported via single-degree-of-freedom rotary joints 9a, 9b, 9c of three pairs of links L1, L2, L3, cylinder tubes 7a, 7b, 7c to be single-degree-of-freedom linear motion mechanisms of the links L1, L2, L3 and single-degree-of-freedom rotary joints 10a, 10b, 10c on the opposite side of cylinder shafts 8a, 8b, 8c are connected with motor shafts 11a, 11b, 11c of motors 12a, 12b, 12c and movable body 5 is revolved in prescribed positive and negative directions till a limit mechanism limiting the moving ranges of the linear motion mechanisms of the links L1, L2, L3 is operated in an origin location adjusting mode, rotation angle information on the motors 12a, 12b, 12c is detected by an encoder and the counters of driver/counter parts D1, D2, D3 and an origin location is calculated by a motor controller 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot device, and more particularly to a robot device capable of performing translational and rotational movements of a gripping mechanism (wrist mechanism) for performing various operations in a plane and simplifying the origin position adjustment. The present invention relates to a robot device which can be performed.

[0002]

2. Description of the Related Art In processing and assembling operations of industrial products, lines are being automated by introducing robots, thereby reducing work time and cost.

In an assembling operation using such a robot apparatus, the robot cannot accurately grasp and assemble the corresponding part due to tolerances, positioning errors of the assembled parts, positioning accuracy of the robot, and the like. In the worst case, the robot body or the robot hand may be damaged, which is an important problem.

[0004] Therefore, conventionally, in order to absorb this displacement, a robot arm and a hand (grasping mechanism) are provided.
A wrist mechanism of an assembly robot having a parallel leaf spring type compliance mechanism for displaceably connecting a hand to the arm and driving means for switching the degree of freedom of the compliance mechanism, wherein the wrist mechanism comprises a pair of parallel leaf springs for x-direction displacement. And a first linear motor formed by laminating a yoke, a coil plate, a permanent magnet, and a yoke, and perpendicular to the driving direction of the first linear motor between a pair of parallel leaf springs for y-direction displacement. There has been proposed a wrist mechanism of an assembly robot in which a second linear motor for giving a drive in the direction is vertically arranged on the first linear motor (see Japanese Patent Publication No. Hei 4-20755). According to the wrist mechanism of the conventional assembly robot, compliance can be obtained by the compliance mechanism in the x direction and the y direction.

[0005]

However, in such a conventional wrist mechanism of a robot, two axes are required.
That is, although appropriate compliance can be ensured in the x direction and the y direction, there is a problem that a compliance in the rotation direction (θ direction) cannot be obtained.

Therefore, the invention according to claim 1 is to provide a movable body provided with a hand with three sets of links having two one-degree-of-freedom rotary joints and a one-degree-of-freedom linear motion mechanism. And the link is connected to the motor shaft of the motor via the one-degree-of-freedom rotary joint, and in the origin position adjustment mode, the movable body moves in a predetermined positive direction and a predetermined negative direction by moving the linear motion mechanism of the link. When rotated until the limit mechanism that limits the range is activated, by calculating the origin position based on the rotation angle information of the motor that rotates with the rotation of the movable body, the translation of the movable body in the plane and It enables movement in the direction of rotation to achieve appropriate compliance, and provides special recovery when the origin position information of the motor is lost, such as when the power of the robot is turned off. The without using easily acquire the home position information, and its object is to provide a robot apparatus capable of performing home position adjustment easily.

According to a second aspect of the present invention, a movable body provided with a hand is supported by three one-degree-of-freedom rotary joints of three sets of links having two one-degree-of-freedom rotary joints and a one-degree-of-freedom linear motion mechanism. The links are connected to the motor shafts of the motors via the one-degree-of-freedom rotation joints, and in the origin position adjustment mode, each motor is driven one by one in a predetermined order to link the movable body in the forward direction. Rotate until the limit mechanism that limits the moving range of the linear motion mechanism operates,
When the rotation angle information of the motor at the position where the limit mechanism that limits the moving range of the linear motion mechanism of the link is activated is obtained, and the rotation of each motor in the forward direction is completed, each motor is sequentially driven one by one in a predetermined order. Then, the movable body is rotated in the negative direction until the limit mechanism operates, the rotation angle information of the motor at the position where the limit mechanism operates is obtained, and the origin position is calculated based on the rotation angle information in the positive direction and the negative direction. As a result, the movable body can be moved in the plane of translation and rotation in the plane to obtain appropriate compliance, and the origin position information of the motor is lost, such as when the power of the robot device is turned off. Sometimes, it is intended to provide a robot device that can automatically acquire the origin position information without using a special jig and can perform the origin position adjustment more easily. It is set to.

According to a third aspect of the present invention, in the origin position adjustment mode, each motor is simultaneously rotated in the forward direction with the same load until the limit mechanism operates, and the rotation angle of the motor at the position where the limit mechanism operates is controlled. When the information is obtained and the rotation of each motor in the positive direction is completed, each motor is simultaneously rotated in the negative direction with the same load until the limit mechanism operates, and the rotation angle information of the motor at the position where the limit mechanism operates is obtained. And calculating the origin position based on the rotation angle information in the positive direction and the negative direction, thereby providing a robot device capable of adjusting the origin position more easily and in a shorter time. And

According to a fourth aspect of the present invention, the load applied to each motor is detected by torque detecting means provided between each motor and each link and detecting the torque applied between each motor and each link. It is another object of the present invention to provide a robot apparatus that can detect a load applied to each motor as a torque and automatically adjust the origin position with high accuracy.

According to a fifth aspect of the present invention, the load applied to each motor is supplied to each motor by detecting the load applied to each motor by current detecting means for detecting a drive current supplied to each motor. Detected as drive current, detected load applied to each motor with simple configuration, inexpensive, and
It is an object of the present invention to provide a robot device that can automatically perform origin position adjustment with high accuracy.

According to a sixth aspect of the present invention, the forward limit angles θi1 (i = 1, i = 1, 2) of the three motors are obtained from the rotation angle information of the motor when the movable body is rotated in the forward direction to the position where the limit mechanism operates. 2, 3), and based on the rotation angle information of the motor when the movable body is rotated in the negative direction to the position where the limit mechanism operates, the negative direction limit angles θi2 (i = 1, 2, 3) of the three motors ) Is obtained and the origin angle θi0, which is the origin position, is calculated from the positive direction limit angle θi1 and the negative direction limit angle θi2 by θi0 = θi1−θi2, so that the origin position can be accurately adjusted by a simple calculation process. It is an object of the present invention to provide a robot device capable of performing the following.

[0012]

According to a first aspect of the present invention, there is provided a robot apparatus comprising: a base member attached to a distal end of a robot arm; a movable body provided with a hand for performing various operations; And the other end of the linear motion mechanism connected to the rotation shaft of the motor via a one-degree-of-freedom rotary joint provided at one end of the one-degree-of-freedom linear motion mechanism. Three sets of links connected to the movable body via a one-degree-of-freedom rotary joint provided at
A limit mechanism provided in the linear motion mechanism of each link to limit a moving range of the linear motion mechanism, an encoder provided in the motor to detect rotation of the motor, and counting a detection result of the encoder, A robot device comprising: a counter for converting the rotation angle information of a motor; and control means for driving each of the motors to drive each of the links to rotate the movable body to rotate the hand to a work position. Wherein the control means has an origin position adjustment mode of the motor, and in the origin position adjustment mode, the movable body is rotated in predetermined positive and negative directions until the limit mechanism operates. The rotation of the motor rotating with the rotation of the movable body is detected by the encoder, and the detection result of the encoder is rotated by the counter. By converting the degree information, by calculating the origin position based on the rotation angle information, it has achieved the above objects.

According to the above construction, the movable body provided with the hand is supported by the one-degree-of-freedom rotary joint of three sets of links having two one-degree-of-freedom rotary joints and a one-degree-of-freedom linear motion mechanism, The link is connected to the motor shaft of the motor via the one-degree-of-freedom rotary joint, and in the origin position adjustment mode, the movable body limits a moving range of the link linear motion mechanism in predetermined positive and negative directions. When rotated until the limit mechanism operates, the origin position is calculated based on the rotation angle information of the motor that rotates with the rotation of the movable body, so that the translation and the movement in the rotation direction within the plane of the movable body are performed. It is possible to obtain appropriate compliance, and when the origin position information of the motor is lost, such as when the power of the robot device is turned off, a special Without using a jig, can easily acquire the position of the origin information, it is possible to perform the origin position adjustment easily.

According to a second aspect of the present invention, there is provided a robot apparatus comprising: a base member attached to a distal end of a robot arm;
The movable body provided with a hand for performing various operations, three motors attached to the base member, and a one-degree-of-freedom rotary joint provided at one end of a one-degree-of-freedom linear motion mechanism. Three sets of links connected to the rotating shaft of a motor and connected to the movable body via a one-degree-of-freedom rotary joint provided at the other end of the linear motion mechanism, and the linear motion mechanism of each link A limit mechanism provided in the motor to limit a moving range of the linear motion mechanism; an encoder provided in the motor for detecting rotation of the motor; and a detection result of the encoder is counted and converted into rotation angle information of the motor. A robot apparatus comprising: a counter; and control means for driving each of the motors to drive each of the links to rotate the movable body to rotate the hand to a working position. The stage has an origin position adjustment mode of the motor, and in the origin position adjustment mode, the motors are sequentially driven one by one in a predetermined order to move the movable body in a predetermined positive direction so that the limit mechanism operates. The rotation of the motor is detected by the encoder, the detection result of the encoder is converted into rotation angle information by the counter, and the rotation angle information of the position where the limit mechanism is operated is obtained, When the rotation of the motor in the positive direction is completed, the motors are sequentially driven one by one in a predetermined order to rotate the movable body in the negative direction until the limit mechanism operates, and the rotation of the motor is controlled by the encoder. And the detection result of the encoder is converted into rotation angle information by the counter, and the rotation of the position where the limit mechanism is operated is determined. Get the degree information,
The above object is achieved by calculating the origin position based on the rotation angle information in the positive direction and the negative direction.

According to the above construction, the movable body provided with the hand is supported by the one-degree-of-freedom rotary joint of three sets of links having two one-degree-of-freedom rotary joints and a one-degree-of-freedom linear motion mechanism, The links are connected to the motor shafts of the motors via the one-degree-of-freedom rotary joints, and in the origin position adjustment mode, each motor is driven one by one in a predetermined order to move the movable body straight in the forward direction. Rotate until the limit mechanism that limits the moving range of the moving mechanism operates, acquire the rotation angle information of the motor at the position where the limit mechanism that limits the moving range of the linear motion mechanism of the link operates, When the rotation is completed, each motor is sequentially driven one by one in a predetermined order, and the movable body is rotated in the negative direction until the limit mechanism operates, and the rotation angle information of the motor at the position where the limit mechanism operates is obtained. And the origin position is calculated based on the rotation angle information in the positive direction and the negative direction, so that the translation and rotation in the plane of the movable body can be performed, and appropriate compliance can be obtained. And automatically obtain the origin position information without using a special jig when the origin position information of the motor is lost, such as when the power of the robot device is turned off. This makes it possible to adjust the origin position more easily.

In this case, for example, as set forth in claim 3, the robot apparatus further includes a load detecting means for detecting a load applied to each of the motors, and the control means is configured to control the load in the origin position adjusting mode. Based on the detection result of the load detecting means, the motors are simultaneously rotated in the forward direction with the same magnitude of load until the limit mechanism is operated, and the converted value of the counter at the position where the limit mechanism is operated is converted. When the rotation angle information is obtained and the rotation of each of the motors in the positive direction is completed, the respective motors are simultaneously rotated in the negative direction with a load of the same magnitude until the limit mechanism operates, and the position at which the limit mechanism operates The rotation angle information obtained by the conversion of the counter is obtained, and the origin position is calculated based on the rotation angle information in the positive direction and the negative direction. It may be of.

According to the above configuration, in the origin position adjustment mode, each motor is simultaneously rotated in the forward direction with a load of the same magnitude until the limit mechanism operates, and the rotation angle information of the motor at the position where the limit mechanism is operated is obtained. When the rotation of each motor in the positive direction is completed, each motor is simultaneously rotated in the negative direction with the same load until the limit mechanism operates, and the rotation angle information of the motor at the position where the limit mechanism operates is obtained. Since the origin position is calculated based on the rotation angle information in the positive direction and the negative direction, the origin position can be adjusted more easily and in a shorter time.

Further, for example, the load detecting means is provided between each of the motors and each of the links, and detects a torque applied between each of the motors and each of the links. It may be a torque detecting means.

According to the above configuration, the load applied to each motor is detected by the torque detecting means provided between each motor and each link and detecting the torque applied between each motor and each link. Can be detected as torque, and the home position can be automatically adjusted with high accuracy.

Further, for example, the load detecting means may be a current detecting means for detecting a drive current supplied to each of the motors.

According to the above configuration, the load applied to each motor is detected by the current detecting means for detecting the drive current supplied to each motor. Therefore, the load applied to each motor is used as the drive current supplied to each motor. The load applied to each motor can be detected with a simple configuration, and the origin position adjustment can be performed automatically at low cost and with high accuracy.

Further, for example, as set forth in claim 6, the control means is configured to control the rotation angle converted by the counter when the movable body is rotated in the forward direction to a position where the limit mechanism operates. The positive limit angles θi1 (i = 1, 2, 3) of the three motors are obtained from the information, and the counter of the counter when the movable body is rotated in the negative direction to the position where the limit mechanism operates is obtained. The negative limit angles θi2 (i = 1, 2, 3) of the three motors are obtained from the converted rotation angle information, and the positive limit angle θi1 and the negative limit angle θi2 are obtained.
From the origin angle θi0 which is the origin position, θi0 = θi1
It may be calculated by -θi2.

According to the above configuration, the forward limit angles θ of the three motors are obtained from the rotation angle information of the motor when the movable body is rotated in the forward direction to the position where the limit mechanism operates.
i1 (i = 1, 2, 3) is obtained, and the negative limit angles θi2 (i) of the three motors are obtained from the rotation angle information of the motor when the movable body is rotated in the negative direction to the position where the limit mechanism operates. = 1, 2, 3), and the origin angle θi0, which is the origin position, is calculated from the positive direction limit angle θi1 and the negative direction limit angle θi2 by θi0 = θi1−θi2. It can be adjusted with high accuracy.

[0024]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 to 8 show a first embodiment of the robot apparatus of the present invention. FIG. 1 shows a robot apparatus to which the first embodiment of the robot apparatus of the present invention is applied. It is a block diagram.

In FIG. 1, a robot device 1 has a wrist mechanism 3 attached to a distal end of a robot arm 2. That is, in the wrist mechanism 3, the base member 4 is fixed to the tip of the robot arm 2.
As shown in FIGS. 2 to 4, three sets of links L1, L2, L
The movable body 5 is attached via 3. A hand 6 is attached to the movable body 5, and the hand 6 grips an assembly component or the like to be worked. Each link L1, L2,
L3 is, as shown in FIG. 5, a cylinder cylinder 7a, 7b, 7
c and a linear motion mechanism composed of cylinder shafts 8a, 8b and 8c, and the ends of the cylinder shafts 8a, 8b and 8c are
It is connected to the movable body 5 via the rotational joints 9a, 9b, 9c. Cylinder cylinder 7 of link L1, L2, L3
a, 7b, and 7c have one-degree-of-freedom rotary joints 10a and 1a.
Motor shafts 11a, 11b, 11c
(Corresponding to the Ja axis, Jb axis, and Jc axis shown in FIG. 4). The motor 12a, 12b is attached to the base member 4 above the motor shafts 11a, 11b, 11c, respectively.
b, 12c are attached, and the motors 12a, 12c
b, 12c are links L1, L2, L3 of the base member 4.
And on the opposite side. The links L1, L2, and L3 are directed in a direction in which the cylinder shafts 8a, 8b, and 8c protrude from the cylinder cylinders 7a, 7b, and 7c (hereinafter, referred to as "links").
The direction of elongation. ) To move to cylinder cylinders 7a, 7b,
The extension of the links L1, L2, L3 is regulated by contacting the ends of the cylinder shafts 7c on the side of the cylinder shafts 8a, 8b, 8c.
In addition, the cylinder shafts 8a, 8b, 8c are cylinder cylinders 7a,
The links L1, L2, L3 are moved in a direction in which they enter the inside of the cylinders 7b, 7c (hereinafter, referred to as contraction directions) and come into contact with the ends on the tip side of the cylinder cylinders 7a, 7b, 7c.
Is restricted in the direction of contraction. That is, the link L
1, L2 and L3 are one-degree-of-freedom rotary joints 9a, 9b and 9c.
And a linear motion mechanism composed of rotary joints 10a, 10b, and 10c, cylinder cylinders 7a, 7b, and 7c, and cylinder shafts 8a, 8b, and 8c.
b and 12c are connected, and the movable body 5 is held rotatably at a predetermined angle in a state parallel to the base member 4. The links L1, L2, and L3 are provided with hard limiters in the extending and contracting directions of the linear motion mechanism.

Although not shown, the motors 12a, 12b, and 12c each include an encoder for detecting the rotation of each of the motors 12a, 12b, and 12c, and each has a driver / counter unit D1, D2, or D3 shown in FIG. Is driven to rotate. That is, the driver counter unit D
1, D2, and D3 include driver circuits, counters, and A / D conversion circuits for the motors 12a, 12b, and 12c, and rotate and drive the motors 12a, 12b, and 12c based on control signals from the motor controller 13. , The encoder values from the encoders of the motors 12a, 12b, 12c are counted by the counter, and A (analog)
/ D (digital) conversion, the motors 12a, 12b, 1
It outputs to the motor controller 13 as rotation angle information of 2c.

The motor controller 13 includes, for example, a CP
U (Central Processing Unit), ROM (Read Only)
Memory), a RAM (Random Access Memory), and the like.
A motor control processing program for driving and controlling the motors 2b and 12c and an origin position adjustment processing program are stored, and various data necessary for executing the processing programs are stored. Motor controller 13
Uses the RAM as a work memory based on the program in the ROM, while using the driver / counter sections D1 and D1.
2, drive control of the motors 12a, 12b, 12c via D3 and an origin position adjustment process. The motor controller 13 stores the origin position information acquired in the origin position adjustment processing in the RAM. However, when the power of the robot apparatus 1 is turned off, the origin position information stored in the RAM is lost. .

Next, the operation of this embodiment will be described. The robot apparatus 1 includes a movable body 5 to which a hand 6 is attached.
However, the one-degree-of-freedom rotary joints 9a, 9b, 9c, the one-degree-of-freedom rotary joints 10a, 10b, 10c and the cylinder cylinders 7a, 7
b, 7c and three links L1, L2, L3 provided with a linear motion mechanism composed of cylinder shafts 8a, 8b, 8c. The other ends of the links L1, L2, L3 are each the tip of the robot arm 2. Of the motors 12a, 12b, 12c fixed to the base member 4 attached to the motor shaft 1
1a, 11b, 11c.

Accordingly, the movable body 5 to which the hand 6 is attached can be translated in parallel with the base member 4 and can rotate by a predetermined angle. Direction, Y direction (base member 4
When a displacement occurs in the direction (parallel to the direction) or the θ (rotation) direction, the links L1, L2, and L3 corresponding to the displacement direction of the movable body 5 are expanded and contracted by driving the motors 12a, 12b, and 12c. Alternatively, by rotating, the movable body 5 can be translated or rotated in the direction of the displacement. As a result, the displacement between the hand 6 and the component can be absorbed, and appropriate compliance can be exhibited.

The motors 12a, 12b, 12
c is driven to rotate with reference to the origin position, so that the links L1, L2, and L3 are appropriately expanded, contracted, or rotated, and exhibit appropriate compliance. However, the robot apparatus 1 stores the origin position information in the RAM of the motor controller 13, and when the power of the robot apparatus 1 is turned off, the origin position information stored in the RAM is lost. Therefore, when the origin position information of the robot device 1 is lost, it is necessary to newly store the origin position information in the RAM of the motor controller 13.

When the power is turned on, the robot apparatus 1 loses the origin position information stored in the RAM of the motor controller 13 when the power of the robot apparatus 1 is turned off. Motor controller 1
The origin position adjustment processing is performed based on the origin position adjustment processing program stored in the ROM 3.

That is, when the power of the robot apparatus 1 is turned on, the motor controller 13 operates the motors 12a, 1a.
At this time, the servo control of the motors 12a, 12b, 12c is turned off, and the motors 12a, 12b, 12c are turned off, and the motors 12a, 12b, 12c can be rotated by an external force. To

In this state, the operator of the robot apparatus 1 manually rotates the movable body 5 around the Z axis, that is, around the center axis of the robot arm 2. That is, when the power of the robot apparatus 1 is turned on, the links L1, L2,
Assuming that the positions of L3 and the movable body 5 are in the initial state as shown in FIG. 6, the operator of the robot apparatus 1 first moves the movable body 5 in the forward direction (FIG. 6) as shown in FIG. And clockwise in FIG. 7), the link L
1, L2 and L3 are cylinder shafts 8 as shown in FIG.
a, 8b and 8c move in the direction of extension,
The a, 8b, and 8c abut on the ends of the cylinder cylinders 7a, 7b, and 7c in the direction of extension, so that a hard limit is applied and the locked state shown in FIG. Then, at this time, the motor shafts 11a of the motors 12a, 12b, 12c,
11b, 11c are rotated by links L1, L2, L3, and the rotation of the motors 12a, 12b, 12c is detected by an encoder built in the motors 12a, 12b, 12c, and the driver / counter units D1, D2, Output to D3. The driver / counter units D1, D2, D3 are:
Encoder values input from the encoders of the motors 12a, 12b and 12c are counted and output to the motor controller 13 as rotation angle information. When the movable body 5 falls into the locked state due to the hard limit, the motor controller 13 sets the driver / counter units D1, D2, D
The rotation angle information, which is the count value of the encoder of each of the motors 12a, 12b, and 12c, input from 3 is stored in the internal RAM as θi1 (i = a, b, c). Here, i is an identifier corresponding to each of the motors 12a, 12b, and 12c. When the links L1, L2, and L3 are in the locked state, the links L1, L2, and L3 are as shown in FIG. From the initial state of θa1, θb1,
It is in the state of θc1.

Next, the operator of the robot apparatus 1 rotates the movable body 5 around the Z axis in a negative direction which is the opposite direction.
When the movable body 5 is rotated in the negative direction, as shown in FIG.
The cylinder shafts 8a, 8b, 8c once move in the contracting direction, then move in the extending direction again, and move in the cylinder shafts 8a, 8b, 8c.
When b and 8c come into contact with the ends of the cylinder cylinders 7a, 7b and 7c in the extending direction, a hard limit is applied and the locked state shown in FIG. At this time, the motor shafts 11a, 11b, 1c of the motors 12a, 12b, 12c are
1c is rotated by links L1, L2, L3, and the rotation of the motors 12a, 12b, 12c is
The encoders 12b and 12c detect the signals and output the detected signals to the driver / counter units D1, D2 and D3. The driver / counter units D1, D2, and D3 count encoder values input from the encoders of the motors 12a, 12b, and 12c and output the counted values to the motor controller 13 as rotation angle information. Motor controller 13
When the movable body 5 falls into the locked state due to the hard limit, the rotation angle information, which is the count value of the encoder of each of the motors 12a, 12b, and 12c input from the driver / counter units D1, D2, and D3 at this time, is θi
2 (i = a, b, c) is stored in the internal RAM. When the links L1, L2, L3 are in the locked state, the links L1, L2, L3 are in the state of angles θa2, θb2, θc2 from the initial state of FIG. 6, as shown in FIG.

The angles θi1 (i = a, b, c) and θi2 (i = a, b,
When c) is obtained, the motor controller 13 calculates the origin angle θi0 (i = a, b, c) from these angles by the following equation.

Θi0 = θi1-θi2 (1) From the above equation (1), the origin angle θi0 (i = a, b, c)
Is calculated, the motor controller 13
Each motor 12a, via the counter section D1, D2, D3,
The motors 12a, 12b,
12c is rotated to the origin angle θi0 (i = a, b, c). The motor controller 13 controls each motor 12a, 1
When 2b and 12c are rotated to the origin angle θi0 (i = a, b, c), they are stopped in that state, the count value of the encoder is set to zero, and the origin angle θi0 (i = a,
After setting the positions b and c) as the origin, the origin position adjustment processing ends.

As described above, according to the present embodiment, the movable body 5 provided with the hand 6 is connected to the two one-degree-of-freedom rotary joints 9a, 9b, 9c, the one-degree-of-freedom rotary joints 10a, 10b,
Cylinder cylinders 7a and 7 which are linear motion mechanisms having 10c and one degree of freedom.
b, 7c and three sets of links L1, L2, L3 having cylinder axes 8a, 8b, 8c, the one-degree-of-freedom rotary joint 9a,
9b, 9c, the links L1, L2, L
3 is connected to the motor shafts 11a, 11b, 11c of the motors 12a, 12b, 12c via the one-degree-of-freedom rotary joints 10a, 10b, 10c, respectively. Motors 12a, 12b, which rotate with the rotation of the movable body 5 when the limit mechanism for limiting the moving range of the linear motion mechanism of the links L1, L2, L3 is actuated in the negative direction.
Since the origin position is calculated based on the rotation angle information 12c, the movable body 5 can be translated and moved in the rotation direction (θ direction) within the plane, and appropriate compliance can be obtained. And the motors 12a, 12a, 12a
When the origin position information of b and 12c is lost, the origin position information can be easily obtained without using a special jig, and the origin position can be easily adjusted.

FIGS. 9 to 11 are views showing a second embodiment of the robot apparatus according to the present invention. In this embodiment, the origin position adjustment processing of the above embodiment is automatically performed by a motor controller. It is what is done.

The present embodiment is applied to a robot device similar to the robot device of the first embodiment. In the description of the present embodiment, the same device as that of the first embodiment will be described. The same reference numerals are used for the components, and the detailed description is omitted.

FIG. 9 shows a robot apparatus 20 according to this embodiment.
FIG. 2 is a view showing a wrist mechanism 21 of the first embodiment. The wrist mechanism 21 has a motor shaft 11a, 11b, 11c and a torque sensor 2.
2a, 22b and 22c (22c is not shown) are provided, respectively. Each torque sensor 22a, 22b,
22c is the motor shaft 11a, 11b, 11
c by detecting the torque acting on the motor controller 13
Output to The motor controller 13 performs torque control when driving the motors 12a, 12b, 12c based on the detection sensors of the torque sensors 22a, 22b, 22c.

The motor controller 13 has its ROM
In addition, an origin position adjustment processing program for automatically performing the origin position adjustment processing and a target torque Tr of each of the motors 12a, 12b, 12c (for example, the motors 12a, 12b, 12c).
) Is stored, and the origin position adjustment processing as shown in FIG. 10 is performed based on the origin position adjustment processing program.

That is, the motor controller 13 controls the motors 12a, 12b, 12c for each of the motors 12a, 12b, 12c.
Motor shafts 11a, 11b, 11c of 12b, 12c (J
a-axis, Jb-axis, Jc-axis)
3. A proportional-gain circuit (PI gain circuit) 24 is configured, and based on the output of the proportional-gain circuit 24, the motors 12a,
Drive control of 12b and 12c is performed. This motor 12a, 1
The torques Ta, Tb, and Tc applied to the motor shafts 11a, 11b, and 11c of the motor shafts 2b and 12c are transmitted to the torque sensors 22a and 22c.
b, 22c, and outputs to the motor controller 13. The motor controller 13 subtracts the torques Ta, Tb, Tc input from the torque sensors 22a, 22b, 22c by the adder / subtractor 23 from the target torque Tr, Output to the proportional-integral gain circuit 24. The proportional-integral gain circuit 24 controls the driving of the motors 12a, 12b, and 12c by changing the proportional gain (P) and the integral gain (I) of the control loop based on the addition / subtraction result of the adder / subtractor 23. When the motors 12a, 12b, and 12c are rotationally driven, the movable body 5 rotates through the links L1, L2, and L3, and controls the position of the hand 6 in the rotational direction (θ direction). FIG. 10 shows the motors 12a and 12a.
motor shafts 11a, 1b,
1b, 11c, links L1, L2, L3, movable body 5, and hand 6 are shown as mechanism 25.

Next, the operation of this embodiment will be described. When the power is turned on, the robot apparatus 20 receives an origin adjustment command from a higher-level controller (not shown) of the motor controller 13 (for example, a robot controller),
When the command for origin adjustment is input, the motor controller 13 sequentially rotates the motors 12a, 12b, and 12c one by one in a positive direction from an arbitrary position via the driver / counter units D1, D2, and D3. One motor 12
When a, 12b, and 12c are rotated in the forward direction, the links L1, L of the rotationally driven motors 12a, 12b, and 12c are rotated.
The link L1, L2, L3 adjacent to the link L2, L3 is locked due to the hard limit on the extension side, and the motor controller 13 determines the rotation angle information θi1 at this time.
(I = a, b, c) is obtained. The above processing is performed for each motor 1
2a, 12b, and 12c are sequentially performed, and the rotation angle information θi1 (i = a, b, c) of all the motors 12a, 12b, and 12c in the forward direction is obtained.

Next, the motor controller 13 performs the same processing as described above for the negative direction, and outputs the rotation angle information θi2 (i = a, b, c) at this time to each of the motors 12a, 1a, 1c.
2b and 12c are acquired. When the rotation angle information θi1 and θi2 (i = a, b, c) in the positive direction and the negative direction are acquired, the motor controller 13 performs the operations (1)
The origin angle θi0 is calculated by the equation, and the origin position adjustment processing ends.

That is, when a command for origin adjustment is input from a host control device, the motor controller 13 shown in FIG.
As shown in FIG. 1, the motor 12a, which is the Ja axis, is rotationally driven to rotate the motor shaft 11a in the forward direction (step S1).
1) It is checked whether it is a hard limit, that is, whether it is a torque limit based on the torque Ta from the torque sensor 22a (step S2). At this time, the other motors 12b and 12c are in a free state. If it is not the torque limit in step S2,
The motor controller 13 returns to step S1, and
When the rotation of the a-axis is continued and the torque limit is reached, the motor 12a is stopped, and the rotation of the Ja-axis is stopped (step S3). Further, the motor controller 13 controls the motor 1
With the 2a and 12c in the free state, the motor 12b is rotationally driven to rotate the Jb axis, which is the motor shaft 11b, in the forward direction (step S4), and it is checked whether the torque limit is reached based on the torque Tb from the torque sensor 22b. (Step S5). If it is not the torque limit, the motor controller 13 returns to step S4 and
When the shaft continues to rotate forward and reaches the torque limit, the motor 1
2b is stopped, and the rotation of the Jb axis is stopped (step S6). Further, the motor controller 13 controls the motor 1
With the 2a and 12b in the free state, the motor 12c is rotationally driven to rotate the Jc axis, which is the motor shaft 11c, in the forward direction (step S7), and it is checked whether the torque limit is reached based on the torque Tc from the torque sensor 22c. (Step S8). If it is not the torque limit, the motor controller 13 returns to step S7 and
When the shaft continues to rotate forward and reaches the torque limit, the motor 1
2c is stopped, and the rotation of the Jc axis is stopped (step S9).

When the forward direction torque limit position is detected by the above processing, the motor controller 13 determines the rotation angle which is the count value of the encoder of each of the motors 12a, 12b, 12c input from the driver / counter units D1, D2, D3. The information is represented by θi1 (i = a, b, c), respectively.
And stored in the internal RAM.

Next, the motor controller 13 returns to step S1 and performs the same processing as described above, but at this time, rotates the axes Ja, Jb and Jc in the negative direction. Upon detecting the torque limit position in the negative direction, the motor controller 13 sets the driver / counter units D1, D
2, motors 12a, 12b, 12 input from D3
The rotation angle information, which is the count value of the encoder c, is stored in the internal RAM as θi2 (i = a, b, c). When the motor controller 13 obtains the rotation angle information θi1 and θi2 (i = a, b, c) in the positive direction and the negative direction, the origin angle θi is calculated by the equation (1) as described above.
Calculate 0. When the motor controller 13 performs the above process a plurality of times to accurately obtain the origin position, it outputs an origin adjustment completion signal to the host controller, and ends the origin position adjustment process.

Therefore, according to the present embodiment, the movable body 5 provided with the hand 6 is connected to the two one-degree-of-freedom rotary joints 9a, 9b, 9c, the one-degree-of-freedom rotary joints 10a, 10b,
Cylinder cylinders 7a and 7 which are linear motion mechanisms having 10c and one degree of freedom.
b, 7c and three sets of links L1, L2, L3 having cylinder axes 8a, 8b, 8c, the one-degree-of-freedom rotary joint 9a,
9b, 9c, the links L1, L2, L
3 are connected to the motor shafts 11a, 11b, 11c of the motors 12a, 12b, 12c via the one-degree-of-freedom rotary joints 10a, 10b, 10c, respectively, and in the home position adjustment mode, the motors 12a, 12b, 12c
Are driven one by one in a predetermined order, and the movable body 5 is rotated in the forward direction until a limit mechanism for limiting the moving range of the linear motion mechanism of the links L1, L2, L3 is activated, and the links L1, L
2. When the rotation angle information of the motors 12a, 12b, and 12c at the position where the limit mechanism that restricts the moving range of the linear motion mechanism of L3 is operated is acquired, and the rotation of each of the motors 12a, 12b, and 12c in the positive direction is completed, Each motor 12a, 12b,
12c are sequentially driven one by one in a predetermined order to rotate the movable body 5 in the negative direction until the limit mechanism operates, and the motors 12a, 12b, and 12c at the positions where the limit mechanism operates.
Is obtained, and the origin position is calculated based on the rotation angle information in the positive and negative directions.
Can be moved in the plane of translation and rotation in the plane of the robot, and appropriate compliance can be obtained. Also, when the power of the robot apparatus 1 is turned off, the origin position information of the motor can be obtained. When it is lost, the origin position information can be automatically acquired without using a special jig, and the origin position can be adjusted more easily.

Note that in the second embodiment,
The motors 12a, 12b, and 12c are sequentially rotated one by one to the limit position, and the motors 12a, 12b, and 12c are sequentially rotated.
Although the rotation angle information of the positive and negative limit positions of b and 12c is acquired, the rotation method of the motors 12a, 12b and 12c is not limited to this.
Based on the control block of FIG. 10, a, 12b, and 12c are simultaneously driven to rotate by a predetermined torque of the same magnitude, for example, the target torque Tr, and the rotation angle information when the locked state is reached at the hard limit is obtained. You may make it acquire. In this case, when the motors 12a, 12b, 12c are rotated with the same magnitude of torque, the links L1, L2
2, L3 is locked in the hard limit due to the balance of the forces, and can appropriately acquire the rotation angle information. Therefore, the origin position adjustment can be performed more easily and in a shorter time.

Further, in the second embodiment,
To detect the load on each motor 12a, 12b, 12c, each motor 12a, 12b, 12c and each link L
1, a torque sensor 22a provided between L2 and L3,
22b and 22c, each motor 12
Loads applied to a, 12b, and 12c can be detected as torque, and the origin position can be automatically adjusted with high accuracy.

As described above, the invention made by the inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

For example, in the second embodiment, the load control of the motors 12a, 12b, 12c is performed using the torque sensors 22a, 22b, 22c.
The load control is not limited to the one using the torque sensors 22a, 22b, 22c.
The detection may be performed by detecting the drive currents to a, 12b, and 12c.

In this way, the load is controlled by each motor 12
a, 12b, 12c can be detected as the supplied drive current, and each of the motors 12a, 12b, 1
By detecting the load applied to 2c, the origin position can be automatically adjusted at low cost and with high accuracy.

[0055]

According to the robot apparatus of the first aspect of the present invention, the movable body provided with the hand is connected to three sets of links having two one-degree-of-freedom rotary joints and a one-degree-of-freedom linear motion mechanism. The link is connected to the motor shaft of the motor via the one-degree-of-freedom rotary joint, and the movable body is moved in the predetermined positive and negative directions in the origin position adjustment mode. If the limit mechanism that limits the moving range of the linear motion mechanism is rotated until it operates, the origin position is calculated based on the rotation angle information of the motor that rotates with the rotation of the movable body. Translation and rotation of the robot can be performed, appropriate compliance can be obtained, and the origin position information of the motor, such as when the power of the robot device is turned off, can be obtained. When but which is lost, without using a special jig, can easily acquire the position of the origin information, it is possible to perform the origin position adjustment easily.

According to the robot apparatus of the second aspect of the present invention, the movable body provided with the hand is connected to one of the three sets of links having two one-degree-of-freedom rotary joints and a one-degree-of-freedom linear motion mechanism. And the link is supported by the rotation joint.
In the home position adjustment mode, each of the motors is driven one by one in a predetermined order to move the movable body in the positive direction in the moving range of the linear motion mechanism of the link. Rotation until the limit mechanism operates to obtain the rotation angle information of the motor at the position where the limit mechanism that limits the movement range of the linear motion mechanism of the link is obtained, and when the rotation of each motor in the forward direction is completed,
Each of the motors is sequentially driven one by one in a predetermined order to rotate the movable body in the negative direction until the limit mechanism operates, acquire rotation angle information of the motor at the position where the limit mechanism is operated, and obtain the positive and negative directions. Since the origin position is calculated on the basis of the rotation angle information, translation and rotation in the plane of the movable body can be performed, and appropriate compliance can be obtained. When the origin position information of the motor is lost, such as when it is turned off, the origin position information can be automatically acquired without using a special jig, further improving the origin position adjustment. Easy to do.

According to the robot apparatus of the third aspect of the present invention, in the origin position adjustment mode, each motor is simultaneously rotated in the forward direction with the same load until the limit mechanism is operated, and the position where the limit mechanism is operated is set. When the rotation angle information of the motors is acquired and the rotation of each motor in the positive direction is completed, each motor is simultaneously rotated under the same load in the negative direction until the limit mechanism operates, and Since the rotation angle information of the motor is acquired and the origin position is calculated based on the rotation angle information in the positive direction and the negative direction, the origin position can be adjusted more easily and in a shorter time.

According to the robot apparatus of the invention, the load applied to each motor is provided between each motor and each link, and the torque detecting means detects the torque applied between each motor and each link. Thus, the load applied to each motor can be detected as torque, and the origin position can be automatically adjusted with high accuracy.

According to the robot device of the present invention, the load applied to each motor is detected by the current detecting means for detecting the drive current supplied to each motor. The load applied to each motor can be detected with a simple configuration, and the origin position can be automatically adjusted at low cost and with high accuracy.

According to the robot apparatus of the sixth aspect of the present invention, the forward limit angles θi1 of the three motors are obtained from the rotation angle information of the motor when the movable body is rotated in the forward direction to the position where the limit mechanism operates. (I = 1, 2, 3), and based on the rotation angle information of the motor when the movable body is rotated in the negative direction to the position where the limit mechanism operates, the negative direction limit angles θi2 (i = 1, 2, 3), and the origin angle θi0, which is the origin position, is calculated from the positive limit angle θi1 and the negative limit angle θi2 by θi0.
= Θi1−θi2, the origin position can be adjusted with high accuracy by a simple calculation process.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a robot apparatus to which a first embodiment of a robot apparatus according to the present invention is applied.

FIG. 2 is an enlarged front view of the wrist mechanism shown in FIG. 1;

FIG. 3 is an enlarged front partial sectional view of a motor portion of the wrist mechanism shown in FIG. 2;

FIG. 4 is a bottom view of the base member of FIG. 2;

FIG. 5 is an enlarged front sectional view of the link in FIG. 4;

6 is a bottom partial cross-sectional view of a base member in an initial state of an origin position adjustment process performed by the robot apparatus of FIG. 1;

FIG. 7 is a bottom partial cross-sectional view of the base member when the motor of FIG. 6 is rotated in the forward direction and is in a locked state.

8 is a partial cross-sectional view of the bottom surface of the base member when the motor shown in FIG. 6 is rotated in the negative direction and locked.

FIG. 9 is an enlarged front view of a wrist mechanism of a robot device to which a second embodiment of the robot device according to the present invention is applied.

FIG. 10 is a diagram showing a control block of an origin position adjusting process of the robot device of FIG. 9;

FIG. 11 is a flowchart showing an origin position adjustment process by the robot device of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Robot apparatus 2 Robot arm 3 Wrist mechanism 4 Base member 5 Movable body 6 Hand 7a, 7b, 7c Cylinder cylinder 8a, 8b, 8c Cylinder axis 9a, 9b, 9c 1-degree-of-freedom rotation joint 11a, 11b, 11c Motor axis 12a, 12b, 12c Motor L1, L2, L3 Link 13 Motor Controller D1, D2, D3 Driver / Counter Unit 20 Robot Device 21 Wrist Mechanism 22a, 22b, 22c Torque Sensor 23 Adder / Subtractor 24 Proportional-Gain Circuit 25 Mechanism

Claims (6)

[Claims] 1. A base member attached to a distal end of a robot arm, a movable body provided with a hand for performing various operations, three motors attached to the base member, and a linear motor having one degree of freedom. The movable body is connected to a rotation shaft of the motor via a one-degree-of-freedom rotary joint provided at one end of a moving mechanism, and is connected to a one-degree-of-freedom rotary joint provided at the other end of the linear motion mechanism. Three sets of links connected to the link, a limit mechanism provided on the linear motion mechanism of each link to limit a moving range of the linear motion mechanism, and an encoder provided on the motor and detecting rotation of the motor, A counter that counts the detection result of the encoder and converts it into rotation angle information of the motor, and drives each of the motors to drive each of the links to rotate the movable body and move the hand to the working position. Control means for rotating and driving, wherein the control means has an origin position adjustment mode of the motor, and in the origin position adjustment mode, the movable body moves in a predetermined positive direction and a predetermined negative direction. When rotated until the limit mechanism operates, the rotation of the motor that rotates with the rotation of the movable body is detected by the encoder, and the detection result of the encoder is converted into rotation angle information by the counter. A robot apparatus for calculating an origin position based on the rotation angle information. 2. A base member attached to the distal end of a robot arm, a movable body provided with a hand for performing various operations, three motors attached to the base member, and a linear motor having one degree of freedom. The movable body is connected to a rotation shaft of the motor via a one-degree-of-freedom rotary joint provided at one end of a moving mechanism, and is connected to a one-degree-of-freedom rotary joint provided at the other end of the linear motion mechanism. Three sets of links connected to the link, a limit mechanism provided on the linear motion mechanism of each link to limit a moving range of the linear motion mechanism, and an encoder provided on the motor and detecting rotation of the motor, A counter that counts the detection result of the encoder and converts it into rotation angle information of the motor, and drives each of the motors to drive each of the links to rotate the movable body and move the hand to the working position. A control means for driving the motor to rotate, wherein the control means has an origin position adjustment mode of the motor, and in the origin position adjustment mode, one motor is sequentially arranged in a predetermined order. The movable body is rotated in a predetermined positive direction until the limit mechanism operates, the rotation of the motor is detected by the encoder, and the detection result of the encoder is converted into rotation angle information by the counter. When the rotation angle information of the position where the limit mechanism is operated is obtained, and the rotation of each motor in the positive direction is completed, the motors are sequentially driven one by one in a predetermined order to move the movable body in the negative direction. The rotation of the motor is detected by the encoder, and the detection result of the encoder is detected by the counter. Rolling angle information is converted to acquire the rotation angle information of the position where the limit mechanism is actuated, the robot apparatus and calculates the origin position based on the positive and negative directions the rotation angle information. 3. The robot apparatus further comprises load detecting means for detecting a load applied to each of the motors, wherein the control means in the origin position adjusting mode, based on a detection result of the load detecting means, The motors are simultaneously rotated in the forward direction with the same load until the limit mechanism operates, and the rotation angle information converted by the counter at the position where the limit mechanism is operated is acquired, and the positive and negative of each motor is obtained. When the rotation in the direction is completed, the respective motors are simultaneously rotated in the negative direction under the same load until the limit mechanism is operated, and the converted rotation angle information of the counter at the position where the limit mechanism is operated is obtained. The robot apparatus according to claim 2, wherein the origin position is calculated based on the rotation angle information in the positive direction and the negative direction. 4. The load detecting means according to claim 1, wherein said load detecting means is provided between said motors and said links, and is a torque detecting means for detecting a torque applied between said motors and said links. Item 4. The robot device according to item 3. 5. The robot apparatus according to claim 3, wherein said load detecting means is a current detecting means for detecting a drive current supplied to each of said motors. 6. The control means according to claim 3, wherein said control means includes means for calculating said three-dimensional value from said rotation angle information converted by said counter when said movable body is rotated in said forward direction to a position where said limit mechanism operates.
Positive limit angles θi1 (i = 1, 2,
3), and based on the rotation angle information converted by the counter when the movable body is rotated in the negative direction to the position where the limit mechanism operates, negative direction limit angles θi2 (i of the three motors are obtained. = 1, 2, 3),
From the positive limit angle θi1 and the negative limit angle θi2, the origin angle θi0, which is the origin position, is defined as θi0
The robot apparatus according to any one of claims 1 to 5, wherein the calculation is performed by: =? I1-? I2.