JPH07116975A - Industrial robot - Google Patents

Abstract

PURPOSE:To easily recognize a maintenance period of an articulation part by measuring a deviation between a target turn position and an actual turn position of each arm compared with a permissible deviation, and manifesting a maintenance request relating to an articulation of supporting the arm whose deviation value exceeds the permissible deviation. CONSTITUTION:An action checking value program, having a turning range to a degree capable of confirming action of each arm, is left as stored in a control device 7 by an operator. When started, a robot 1 is actuated in accordance with the value program, and in the control device 7, by the first position detector 51 at each fixed sampling time, a turn angle of the first turning arm 31 is detected to calculate a difference from a prescribed locus in a deviation calculating means 71. Whether these calculated deviations exceed a permissible deviation or not is discriminated by a discriminating means 72, to output a signal therefrom in the case of being displaced from a permissible moving region, and a display lamp 73 is lighted, to also sound an alarm buzzer 74 for informing the operator of this fact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining joints in an industrial robot.

[0002]

2. Description of the Related Art Conventionally, the joints of industrial robots require maintenance inspections such as lubrication at regular intervals, and the maintenance inspection time is determined by the operating time of the robot.
However, the operating time of the robot does not match the actual operating time of the joints, and judging by the operating time,
There were times when unnecessary maintenance work was carried out. As an example of eliminating such waste, there is a "robot operating time measuring method" described in JP-A-63-74591. That is, only the operating time that the motor is actually operating is calculated as the operating time of the robot,
Prevents unnecessary maintenance work.

[0003]

In such a robot operating time measuring method, only the operating time of the motor is used as a judgment factor, so that the operating environment of the motor (work atmosphere, load content, etc.) must be taken into consideration. Therefore, it may not always be a guideline for proper maintenance and inspection. Therefore, in the present invention, whether or not the joint portion of the robot actually needs maintenance and inspection is determined from the following performance of the joint portion,
It is an object to provide an industrial robot that notifies appropriate maintenance and inspection time.

[0004]

In the industrial robot of the present invention, a position detector for detecting the actual turning position of the arm supported by each joint is attached to each joint so that the commanded target turning position and , The deviation calculation means for obtaining the difference between the turning position of each arm detected by the position detector and each deviation value calculated by this deviation calculation means are compared with a preset allowable deviation, and the deviation value indicates the allowable deviation. A determining means is provided to determine whether or not it exceeds. Then, according to the determination result of the determination means
Make a maintenance requirement asserted for the joint that supports the arm whose deviation exceeds the allowable deviation.

[0005]

The deviation between the actual turning position of the arm and the target value is obtained for each joint, and the joint supporting the arm exceeding the allowable deviation is displayed to the effect that maintenance is required and the operator is notified.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example in which the present invention is applied to a horizontal articulated robot 1. The robot 1 includes a base 10,
First joint 21 and second joint 22, first arm 31 and second arm 32, motors 41 and 42 for driving each arm, first
It comprises a position detector 5, a second position detector 52, an end effector 6, and a controller 7.

The first joint 21 is fixed to the base 10 with its rotating shaft 211 being vertical, and one end of the first arm 31 is attached to the rotating shaft 211. The motor 41 has a rotating shaft 2
It is connected to the upper part of 11 and is rotated to rotate the first arm 31. The first position detector 51 is an absolute encoder built in the first joint, and includes a rotary shaft 2
It is connected to the lower part of 11 and detects the turning position of the first arm at the first joint as an absolute value. The second joint 22 is provided at the other end of the first arm with its rotation axis 221 vertical.
One end of the second arm 32 is attached to the rotating shaft 221. The motor 42 is connected to the upper part of the rotary shaft 221,
This is rotated to rotate the second arm 32. The second position detector 52 is an absolute encoder attached to the lower part of the second joint, is connected to the lower part of the rotary shaft 221, and detects the turning position of the second arm at the second joint as an absolute value.

In the case of FIG. 1, the end effector 6 is a lifting hand unit and is attached to the tip of the second arm 32. The end effector 6 has a Z-axis 61 that vertically moves up and down with respect to a horizontal plane, and a holding hand 62 is attached to the lower end of the Z-axis 61 to hold parts and move them up and down. The control device 7 is a control device of the robot 1 and drives each of the motors 41 and 42 to drive each of the arms 3
The end effector 6 is controlled by numerically controlling the turning motions of 1 and 32.
The vertical movement of the Z axis, the θ rotation operation around the vertical movement axis, and the gripping operation of the hand are controlled. Reference numeral 71 denotes a deviation calculating means for obtaining a difference between a target turning position of each arm which is previously input to the control device 7 by a robot operation program and an actual turning position of each arm detected by each position detector. Built into the device 7. 72 is
The discriminating means, which compares the respective deviation values calculated by the deviation calculating means 71 with the permissible deviation inputted in advance and judges whether or not the deviation value exceeds the permissible deviation, is also incorporated in the control device 7.

The control device 7 issues a maintenance request signal for the joint supporting the arm whose deviation value exceeds the allowable deviation based on the judgment result of the judgment means 72, and drives the display means and the like. For example, in FIG. 1, display lamps 73 and 74 are attached to the upper surface of the control device 7, and the first joint and the second joint are made to correspond to each other. When the deviation value of the first arm exceeds the allowable deviation, the display lamp 73 is turned on, and when the deviation value of the second arm exceeds the allowable deviation, the display lamp 74 is turned on. At this time, a warning buzzer or the like may be sounded to alert the operator.

The operation of this embodiment having such a configuration will be described. First, the operator stores in the control device 7 an operation checking numerical program having a turning range in which the operation of each arm can be confirmed. Next, the controller 1 is turned on and the robot 1 is started.
The above-mentioned operation checking numerical program is called, and the robot 1 is operated according to the numerical program. Figure 2
In the present embodiment, a method for determining whether or not maintenance is required for a joint is described, where the vertical axis is the arm rotation angle D and the horizontal axis is the operation time T. A locus a indicated by a one-dot chain line is a target movement locus that the first arm 31 should turn by the operation checking numerical program,
The hatched area S corresponds to the locus a and is discriminator 7
The allowable deviation value input to 2 is added or subtracted to show the allowable movement region where the first arm 31 should actually move.

The control device 7 causes the first position detector to detect the actual turning angle of the first arm 31 at regular sampling intervals with respect to the first arm 31 that is turning according to the operation checking numerical program. Deviation calculation means 71
To calculate the difference from the trajectory a. Then, the discriminating unit 72 discriminates whether or not the calculated deviations exceed the allowable deviations. Now, as shown in the figure, the actual turning angle of the first arm 31 is as shown by the locus b, and the allowable movement region S
If it is out of the range (moves outside the allowable deviation), the discriminating means 72 outputs the information to the control device 7. Upon receiving this information, the control device 7 turns on the display lamp 73 and sounds a warning buzzer to notify the operator to that effect. Regarding the second arm 32, the second position detector detects the actual turning angle, the display lamp 74 is turned on by the same operation, and the warning buzzer sounds. Further, the locus b is within the allowable movement area S (moving within the allowable deviation).
In this case, the control device 7 executes the operation numerical program following the operation checking numerical program, and causes the robot 1 to perform the actual assembling work and the like.

In this embodiment, the maintenance request for the joints is expressed by turning on the display lamp provided in the control device 7. However, a warning buzzer sounds and an error is displayed on the liquid crystal display of a teaching box (not shown). It may be displayed as a message. Further, although the joint portion of the horizontal articulated robot has been described in the present embodiment, it can be easily applied to the joint portion of the vertical articulated robot.

[0013]

According to the present invention, the deviation between the actual turning position of the arm and the target value is obtained for each joint, and the joint supporting the arm exceeding the allowable deviation is indicated as requiring maintenance. Therefore, the operator can automatically know the maintenance time of the joint. Since this maintenance request notification is based on mechanical values due to changes over time, the operating environment of the robot (work atmosphere, load content, etc.) is eventually taken into consideration, and it is possible to know the appropriate maintenance inspection time, It is possible to carry out efficient maintenance work.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an industrial robot of the present invention.

FIG. 2 is an explanatory diagram showing a method for determining whether or not a joint requires maintenance in the embodiment.

[Explanation of symbols]

 1 Robot 21,22 1st, 2nd joint 31,32 1st, 2nd arm 41,42 Motor 51,52 1st, 2nd position detector 6 End effector 7 Control device 71 Deviation calculation means 72 Discrimination means 73, 74 indicator lamp

Claims (2)

[Claims] 1. An industrial robot having a plurality of joints, wherein a deviation between a target turning position of each arm and an actual turning position is measured, each deviation value is compared with a preset allowable deviation, and the deviation is compared. An industrial robot characterized by expressing a maintenance request for a joint that supports an arm whose value exceeds a permissible deviation. 2. A position detector which is provided for each joint and detects an actual turning position of an arm supported by each joint, a commanded target turning position, and an arm which is detected by the position detector. Deviation calculating means for obtaining the difference from the turning position, comparing each deviation value calculated by the deviation calculating means with a preset allowable deviation, and judging means for judging whether the deviation value exceeds the allowable deviation, The industrial robot according to claim 1, further comprising: a control unit that displays a joint that supports the arm when the deviation value exceeds a permissible deviation based on the result of the judgment by the judgment unit.