JPH0871966A - Robot control device - Google Patents

Abstract

PURPOSE: To compensate for backlash of a driving system gear in a multiaxial control type robot. CONSTITUTION: A 6-axial multi-joint robot 10 clamps a cylindrical reference unit B by means of a hand 18. A displacement detector S1 is clamped on a displacement detector holder 50. The distal end part of the displacement detector S1 is located in the reference unit B in a noncontact condition. When a control shaft is normally and reversely rotated, the displacement detector S1 makes contact with the reference unit B. At that time, a CPU takes up angular data concerning the control shaft from an encoder and stores in memory, and then, computes a degree of backlash of a control shaft driving system gear, from data in memory. The CPU delivers an alarm signal to an alarm when the degree of backlash exceeds a specific value so that the alarm is energized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-axis robot controller for a control axis drive system, which warns and compensates for position and trajectory deviations caused by an increase in backlash due to aging. .

[0002]

2. Description of the Related Art Conventionally, deterioration of gears for driving each control axis occurs due to secular change due to long-term use of an articulated robot,
As the backlash of the gears increased, the accuracy of the position and the trajectory decreased. As a countermeasure, the robot itself did not have a means to grasp the situation of the increase of gear backlash, so the position of the robot was found and the position of the robot was detected after the quality control of the product. And the deviation of the trajectory was corrected.

[0003]

However, there is a problem that stable quality cannot be secured because the cause is investigated after receiving the result of quality control, and because of the post-processing method. There is a problem that it is unproductive, and in some cases, the control axis drive system of the robot may be worn or damaged.

Therefore, an object of the present invention is to detect the displacement amount of backlash on a regular basis before receiving the result of quality control, thereby grasping the deviation of the position and trajectory of the robot due to aging, and issuing an alarm. By stabilizing the robot and compensating the position, the product quality is stabilized and productivity is improved, and in addition, the control axis drive system of the robot is prevented from being worn or damaged. Is.

[0005]

According to the present invention, as a means for achieving the above-mentioned object, the means described in claim 1 is
In a robot control device for controlling a robot including a motor that drives a movable part via a speed reduction mechanism, and a position detection unit that is disposed on the motor side with respect to the speed reduction mechanism and that detects the position of the movable part, at least One of a reference device having two inner wall surfaces and a displacement detector having a contact that can be inserted between the inner wall surfaces of the reference device is provided in a movable part of the robot, and the other is fixed to a fixed part to detect displacement. Means for relatively moving the measuring device and the reference device in the forward and reverse directions, and the contact of the displacement detector contacts two inner wall surfaces of the reference device facing each other by the relative movement in the forward and reverse directions by the moving device. The movement amount detecting means for detecting the relative movement amount of the displacement detector and the reference device at this time by the position detecting means, and the robot based on the relative movement amount detected by the movement amount detecting means. It is obtained and output means for outputting an output value to verify the amount of backlash of bets.

The means described in claim 2 is a motor for driving a movable part through a speed reducing mechanism, and a position detecting means arranged on the motor side with respect to the speed reducing mechanism for detecting the position of the movable part. In a robot control device for controlling a robot including: a reference device having at least two inner wall surfaces facing each other, and a displacement detector having a contact insertable between the inner wall surfaces of the reference device. A moving means provided on the movable part and the other fixed to the fixed part, for moving the displacement detector and the reference device relative to each other in the forward and reverse directions, and the displacement detector by the relative movement in the forward and reverse directions by the moving means. Movement amount detecting means for detecting that the contact of the contactor has come into contact with two inner wall surfaces of the reference device facing each other, and the relative movement amount between the displacement detector and the reference device at this time is detected by the position detecting means,
Based on the relative movement amount detected by the movement amount detection means and a predetermined reference value, a determination means for determining whether or not the robot continues to be used, and an output means for outputting the determination result by the determination means. It is equipped with.

According to a third aspect of the present invention, there is provided a motor for driving a movable portion via a speed reducing mechanism, and position detecting means arranged on the motor side of the speed reducing mechanism for detecting the position of the movable portion. In a robot controller for controlling a robot equipped with the robot, one of a reference device having at least two inner wall surfaces facing each other and a displacement detector having a contact insertable between the inner wall surfaces of the reference device is provided as a movable part of the robot. And the other is fixed to the fixed part, the displacement detector and the reference device are moved relative to each other in the forward and reverse directions, and the displacement detector is brought into contact by the relative movement in the forward and reverse directions by the moving means. A moving amount detecting means for detecting the relative movement amount of the displacement detector and the reference device at this time by the position detecting means by detecting that the child has contacted two inner wall surfaces of the reference device, and this moving amount detection. By means Based on the detected relative movement amount Te, in which a correction means for correcting the command value for controlling the robot.

According to a fourth aspect of the present invention, the output value of the output means is a center value of two inner wall surfaces of the reference device which face each other or a distance between two inner wall surfaces of the reference device which face each other. It is what

According to a fifth aspect of the present invention, the determining means compares the shipping data of the robot with the relative movement amount detected by the movement amount detecting means.
It is characterized by determining whether or not to continue using the robot.

[0010]

The means described in claim 1 moves the displacement detector and the reference device relative to each other in the forward and reverse directions by the moving means. Then, the movement amount detecting means detects that the contacts of the displacement detector contact two inner wall surfaces of the reference device facing each other, and the relative movement amount between the displacement detector and the reference device at this time is detected by the position detecting means. To detect. Based on this output value, the output means outputs an output value for confirming the backlash amount of the robot.

According to a second aspect of the present invention, the displacement detector relatively moves the displacement detector and the reference device in the forward and reverse directions by the moving means. Then, the movement amount detecting means detects that the contacts of the displacement detector contact two inner wall surfaces of the reference device facing each other, and the relative movement amount between the displacement detector and the reference device at this time is detected by the position detecting means. To detect. Based on this output value, the determination means determines whether or not to continue using the robot, and the output means outputs this determination result.

According to a third aspect of the present invention, the displacement detector relatively moves the displacement detector and the reference device in the forward and reverse directions by the moving means. Then, the movement amount detecting means detects that the contacts of the displacement detector contact two inner wall surfaces of the reference device facing each other, and the relative movement amount between the displacement detector and the reference device at this time is detected by the position detecting means. To detect. The correction means corrects the command value for controlling the robot based on this output value.

According to a fourth aspect of the present invention, the output means uses, as an output value for confirming the backlash amount of the robot, the center value of two inner wall surfaces of the reference device or two of the two inner wall surfaces of the reference device which are opposed to each other. Output the distance between the walls.

According to a fifth aspect of the present invention, the determining means compares the data at the time of shipment of the robot with the relative movement amount detected by the movement amount detecting means to determine whether or not the robot continues to be used. A determination is made, and the result of this determination is output by the output means.

[0015]

As described above, according to the present invention, the amount of backlash can be automatically known by the relative movement of the reference device and the displacement detector by the robot.
That is, in claim 1, the worker can know the backlash amount of the robot by outputting the value based on the relative movement amount of the displacement detector and the reference device. Claim 2
In order to determine whether or not to continue using the robot by comparing the amount of relative movement between the displacement detector and the reference device with a previously stored reference value, maintenance and inspection are required due to an increase in the amount of backlash. You can know if Therefore, maintenance and inspection work by workers is
From these results, the work can be facilitated because it can be performed only when necessary. In addition, since it is possible to know when maintenance and inspection are required, it is possible to stabilize product quality and prevent accidents or disasters caused by wear or damage of the control axis drive system gear. Preventive maintenance can be achieved. Further, in claim 3, since the position is corrected, further
The work can be facilitated and the accuracy of the robot can be improved.

[0016]

EXAMPLES The present invention will be described below based on specific examples. FIG. 1 is a mechanism diagram showing a mechanism of a robot controller with position compensation. 6-axis articulated robot body 10
Is fixed to the floor by arranging the base 12, and the base 1
The movable part of the robot shown below is attached to the upper part of the robot 2. That is, the column 13 is fixedly mounted on the base 12 and the body 14 is rotatably arranged around the control axis a.
The body 14 rotatably supports an upper arm 15 about a control axis b, and the upper arm 15 rotatably supports a forearm 16 about a control axis c.
At the tip of the forearm 16, the wrist 17 has a control axis d.
It is rotatably supported around the
8 is rotatably supported around the control shaft e and the control shaft f. Further, the hand 18 holds the tubular reference device B.

It should be noted that a hole corresponding to the displacement detector S1 may be provided in the wrist flange portion of the robot or a part of the tool as the reference device B. Further, the reference device B does not necessarily have to be cylindrical and may be a member having two inner wall surfaces facing each other. The displacement detector S1 is a displacement detector holder 5
The contactor at the tip of the displacement detector S1 sandwiched between 0 is set to a size such that it can be positioned inside without contacting the inner wall of the reference device B. And this displacement detector S
Reference numeral 1 is a contact sensor capable of detecting that the contactor has contacted the inner wall of the reference device B. The displacement detector S2, which will be described later, has the same configuration as the displacement detector S1 except that the direction is different. In this embodiment, the robot is provided with the reference device B and the displacement detector S1 is fixed.
Conversely, the displacement detector S1 may be provided in the robot.

FIG. 2 is a block diagram showing the electrical configuration of the robot controller with position compensation. CPU
Reference numeral 20 denotes a central processing unit including a microcomputer, and the CPU 20 includes servo CPUs 22a to 22f for driving servo motors, an alarm device 23, and a displacement detector S.
Input / output interface 2 for inputting the detection signal from 1
4, memory 25, operation panel 26 for instructing jog operation, etc.
Is connected.

A displacement detector S1 and a displacement detector S2 are connected to the input / output interface 24. Servo C
In the PUs 22a to 22f, the deviations between the output angle data θ1 to θ6 from the CPU 20 and the output values from the encoders E1 to E6 (absolute encoders) as position detectors connected to the respective servo motors are calculated, and the deviation values are calculated. Only the minute is output to the servo motors M1 to M6. The servo motors M1 to M6 are servo CPUs 22a to 22f, respectively.
The rotation angles of the control axes a to f are detected by the encoders E1 to E6, respectively. The memory 25 stores the detection data of the reference device B and the position data of the reference device B at the time of shipment.

FIG. 3 is a model of the configuration shown above. A reference motor B provided at the tip of the robot and a servomotor M (M1 for rotating around each control axis af).
To M6), there is a speed reduction mechanism 10a which is a source of backlash. In addition, this reduction mechanism 10
Encoders (E1 to E
6) is attached. Therefore, as will be described later, as the amount of backlash increases, the value of the encoder E that measures the inner diameter of the reference device B also increases.

FIG. 4 shows the positional relationship between the displacement detectors S1 and S2 and the world coordinate system. The displacement detector S1 is used for position compensation in the horizontal plane region, and the displacement detector S2 is used for position compensation in the vertical plane region. From the positional relationship between the displacement detector S1 and the world coordinate system, the control axes that can be detected by the displacement detector S1 are two control axes, the a axis and the f axis, and in the displacement detector S2, the b axis to the e axis. 4 control axes can be detected. When the displacement detector S2 is used, the hole of the reference device B needs to be horizontal.

FIGS. 5 and 6 show the operation areas of the 6-axis articulated robot in the horizontal plane and the vertical plane in the apparatus of this embodiment (however, the 6-axis articulated robot in FIGS. 4 and 5 are parallel to each other). Link type.) The shaded areas in this operation area are the horizontal plane and the vertical plane normal use area, which are particularly frequently used areas. In the present embodiment, the normal work is not hindered, and moreover, the frequently used area in the control axis to be detected is
It was set as the area for displacement detection. Therefore, it is desirable that the displacement detector S1 is installed in the non-vertical plane regular area in the horizontal plane regular area, and the displacement detector S2 is desirably installed in the non-horizontal plane regular area in the vertical plane regular area.

Next, the operation will be described. FIG. 7 is a flowchart showing a processing procedure relating to displacement detection of the CPU 20 used in the apparatus of this embodiment. For convenience, here, the a axis is used as the control axis and the
This will be described using 1. First, at the time of displacement detection, the robot is operated and positioned so that the tip of the displacement detector S1 is positioned inside the reference device B. From this state, step 10
At 0, the a-axis is reversely driven at low speed to move the reference device B held by the hand 18 in the minus direction. Since the displacement detector S1 is fixed in space, when the a-axis is reversely driven in step 100, the distance between the inner wall of the reference device B and the tip of the displacement detector S1 is narrowed, and the contact is reached. At this time, this contact state is detected as an electrical conduction signal in step 110, the reverse rotation drive of the a-axis is stopped in step 120, the encoder value at this point is fetched in step 130, and this encoder value is stored in the memory 25 in step 140. To memorize. Thereby, the data of one end of the inner diameter of the reference device B is acquired.

Similarly, in step 150, the a-axis is driven at a low speed in the forward direction to move the reference device B held by the hand 18 in the plus direction. Since the displacement detector S1 is fixed in space, when the a-axis is normally driven in step 150, the other end of the inner wall of the reference device B and the displacement detector S1 are driven.
The distance from the tip of the will decrease, and it will come into contact. At this time, this contact state is detected as an electrical conduction signal in step 160, the forward rotation drive of the a-axis is stopped in step 170, the encoder value at this point is fetched in step 180, and this encoder value is stored in step 190. 25. Thereby, the data of the other end of the inner diameter of the reference device B is also acquired. Step 200
At, the stored data is taken out from the memory 25, and an operation is performed in step 210 using the data. The calculation in step 210 is to calculate the reference position of the reference device B, and the calculation formula shown in Formula 1 is used. Here, the reference position was the center of the inner diameter of the reference device B.

[0025]

[Equation 1] θiNmean = (θiNmax + θiNmin) ÷ 2 ─ (1) where θiNmax is the position data of one end of the inner diameter of the reference device B when the control axis a is driven in the forward direction, and θiNmin is the control axis a.
The position data of the other end of the inner diameter of the reference device B when θ is driven in the reverse direction, θiNmean is the reference position, that is, the center value of the inner diameter. The subscript i means i-th axis and N is N
It means the second data. In this way, the displacement detection of this embodiment is performed periodically, and the number N is given to the detected data in the order.

FIG. 8 is based on the calculation result of the equation (1).
The vertical axis represents the reference position θiNmean and the horizontal axis represents N, which is a graph. Although the graph in Fig. 8 rises to the right,
This is because the reference position θiNmean increases because the amount of backlash of the gear of the control axis drive system increases as the usage time of the robot increases. Θc in the figure is the upper limit value of the reference position for allowing the robot to be used within the range where the quality of the product can be secured, and in step 220, θc and θiNmean are compared. Where θiNmean is θc
If it exceeds the limit, in step 230, the alarm device 2
Output an alarm signal to 3. In addition to the output of the alarm signal to the alarm device 23, a monitor may be displayed on the operation panel 26, or the robot may be automatically stopped. The alarm device 23 may generate an alarm sound or light an alarm lamp upon receiving an alarm signal.

In the flowchart of FIG. 7, steps 100 to 120 and steps 150 to 170 correspond to the moving means,
Steps 130 to 140, Step 18
Steps 0 to 210 correspond to the movement amount detecting means, and step 220 corresponds to the determining means.

In step 230, by outputting an alarm signal in advance before the quality of the product is deteriorated, stable quality can be ensured, and productivity can be improved because it is not post-processing. In addition, it is possible to avoid using the robot with increased backlash due to the occurrence of an alarm, and preventive maintenance such as accidents and disasters caused by wear and damage of the gears of the control axis drive system becomes possible. . The detection frequency of this reference position θiNmean is 1
It is about once.

Next, as a second embodiment, a case of using data of the inside diameter of the reference device B in the alarm generation processing means will be described. The mechanism diagram, block diagram, flow chart, etc. of the entire apparatus of the second embodiment are the same as those of the first embodiment, but in the processing contents of step 210 "calculation" of the flow chart shown in FIG. The feature is that the inner diameter of is used. The arithmetic expression used in step 210 is shown in Expression 2.

[0030]

[Formula 2] ΔiN = θiNmax − θiNmin ─ (2) where θiNmax is the data of the inner diameter of the reference device B when the control axis a is driven in the forward direction, and θiNmin is the reference when the control axis a is driven in the reverse direction. This is data of the inner diameter of the container B, and ΔiN is a value of the data of the inner diameter of the reference device B. The subscript i means the i-th axis and N means the N-th data.

FIG. 9 is based on the calculation result of the equation (2).
The vertical axis represents the data ΔiN of the inner diameter of the reference device B, and the horizontal axis represents N, which is a graph. FIG. 9 also shows an upward-sloping graph because the backlash amount of the control axis drive system increases with the increase of the operating time of the robot, and the data ΔiN of the inner diameter of the reference device B increases. Δc in the figure is the upper limit value of the data of the inner diameter of the standard B for enabling the robot to be used within the range where the quality of the product can be secured, and in step 220, Δc and ΔiN are compared. If ΔiN exceeds Δc, an alarm signal is output to the alarm device 23 in step 230.

As described above, in the first and second embodiments, the position data of one end and the other end when the displacement detector S1 contacts the reference device B are stored. However, a method of measuring the inner diameter of the reference device B by measuring the movement of the reference device B by the number of pulses like a pulse generator may be used. In this case, the position of half the pulse number is the center of the inner diameter. Moreover, in the above-described first and second embodiments, step 220 and step 230.
In, the alarm is output based on the comparison result of θc and θiN. However, depending on the case, θiN may be directly displayed or the comparison result may be displayed.

Further, a third embodiment will be described. The mechanical diagram, block diagram, flow chart, etc. of the entire apparatus in the third embodiment are the same as those in the first and second embodiments. In the flowchart of FIG. 7, the difference between the third embodiment and the first and second embodiments is the content of the arithmetic expression in step 210 “calculation”. The third embodiment is characterized in that the reference position data of the reference device B at the time of shipment is used. The arithmetic expression used in step 210 is shown in Expression 3.

[0034]

[Equation 3] εiN = θi0 − θiNmean ─ (3) where θi0 is the reference position data of the reference device B at the time of shipment, θiNmean is the reference position data of the reference device B at the time of data acquisition, and εiN is the error at that time. The value of the quantity. The subscript i means the i-th axis and N means the N-th data.

FIG. 10 is a graph based on the calculation result of the equation 3 with the error amount εiN on the vertical axis and N on the horizontal axis. FIG. 10 also shows an upward-sloping graph because the error amount εiN increases because the backlash amount of the control axis drive system increases as the usage time of the robot increases. In the figure, εc is the upper limit of the error amount for allowing the robot to be used within the range where the quality of the product can be secured, and in step 220, εc and εiN are compared. If εiN exceeds εc, step 23
At 0, an alarm signal is output to the alarm device 23.

Finally, the fourth embodiment will be described. For the fourth embodiment, the data at the time of shipping is used as in the third embodiment, but the difference from the third embodiment is that it has a backlash compensation function. The mechanical diagram and the block diagram of the entire apparatus in the fourth embodiment are the same as those in the first embodiment, the second embodiment and the third embodiment.

FIG. 1 is a flowchart of the fourth embodiment.
It is shown in FIG. The difference from the flowchart in FIG. 7 is that the tip of the displacement detector S1 is set at the center of the inner diameter of the reference device B before the control axis is moved in step 90 and step 145. In step 240, backlash compensation is performed. The data detected in this embodiment includes data from the center of the inner diameter of the reference device B to one end of the inner wall obtained at the time of forward rotation, and data from the center of the inner diameter of the reference device B detected at the time of reverse rotation to the other end of the inner wall. Data.
The arithmetic expressions used in step 210 are shown in Expression 4 and Expression 5.

[0038]

[Equation 4] εiNmax = θi0max − θiNmax ─ (4)

[0039]

[Equation 5] εiNmin = θi0min − θiNmin ─ (5) where θi0max is the data of the reference device B at the time of forward drive at the time of shipment and θiNmax is the data of the reference device B at the time of forward drive at the time of data acquisition. , ΕiNmax is a value of an error amount at the time of normal rotation driving. Similarly, θi0min is the data of the reference device B at the time of reverse driving at the time of shipping, θiNmin is the data of the reference device B at the time of reverse driving at the time of data acquisition, and εiN
min is the value of the error amount during reverse rotation drive. The subscript i is i
It means the nth axis and N means the Nth data.

FIG. 12 is a graph in which the ordinates represent the error amounts εiNmax and εiNmin and the abscissa represents N, based on the calculation results in the equations 4 and 5. FIG. 12 also shows an upward-sloping graph because the backlash amount of the gears of the control axis drive system increases with the increase in the operating time of the robot, and the error amounts εiNmax and εiNmin increase. In the figure, εc is the upper limit of the error amount for enabling the robot to be used within the range where the quality of the product can be secured. In step 220, εc and εiNmax and εc
And εiNmin are compared. εiNmax and εiNmin are ε
If it exceeds c, an alarm signal is output to the alarm device 23 in step 230.

If εiNmax and εiNmin do not exceed εc, backlash compensation is performed in step 240. That is, in normal rotation driving, εiNmax is
By adding the command from 20 to the servo CPU, by adding εiNmin to the command from the CPU 20 to the servo CPU at the time of reverse driving, backlash can be compensated. The backlash compensation may be automatically performed. Further, although compensation may be performed by a user command, it may be only displayed on the operation panel 26 as a monitor.

[Brief description of drawings]

FIG. 1 is a mechanism diagram showing a positional relationship between a 6-axis articulated robot, a displacement detector, and the like in the apparatus of this embodiment.

FIG. 2 is a block diagram showing an electrical configuration of a robot controller with position compensation in the apparatus of this embodiment.

FIG. 3 is a schematic diagram showing the configuration of the device of this embodiment.

FIG. 4 is an explanatory diagram showing a positional relationship between a world coordinate system and a displacement detector in the device of this embodiment.

FIG. 5 is an explanatory view showing a region used in a horizontal plane region in the apparatus of this embodiment.

FIG. 6 is an explanatory diagram showing a region used in a vertical plane region in the apparatus of this embodiment.

FIG. 7 is a flowchart showing a processing procedure used in the first embodiment, the second embodiment, and the third embodiment of the apparatus of this embodiment.

FIG. 8 is an explanatory diagram showing changes in data detected in the first embodiment.

FIG. 9 is an explanatory diagram showing changes in data detected in the second embodiment.

FIG. 10 is an explanatory diagram showing changes in data detected in the third embodiment.

FIG. 11 is a flowchart showing a processing procedure used in a fourth embodiment of the apparatus of this embodiment.

FIG. 12 is an explanatory diagram showing changes in data detected in the fourth embodiment.

[Explanation of symbols]

 10 Robot main body 18 Hand 50 Displacement detector holder O, X, Y, Z World coordinate system a to f Control axis M1 to M6 Servo motor E1 to E6 Encoder B Reference device S1 Displacement detector for a-axis and f-axis ( Horizontal plane area) S2 Displacement detector for b-axis and e-axis (vertical plane area)

Claims (5)

[Claims] 1. A robot having a motor for driving a movable part via a speed reduction mechanism, and position detecting means arranged on the motor side of the speed reduction mechanism for detecting the position of the movable part. In the robot controller, one of a reference device having at least two inner wall surfaces facing each other and a displacement detector having a contact insertable between the inner wall surfaces of the reference device is provided in the movable part of the robot,
The other of the displacement detector is fixed to the fixed portion, and the displacement detector and the reference device are relatively moved in the forward and reverse directions, and the displacement detector is moved by the relative movement in the forward and reverse directions. A movement amount detecting means for detecting that the contactor has contacted two inner wall surfaces of the reference device which face each other, and for detecting the relative movement amount of the displacement detector and the reference device at this time by the position detecting means. A robot controller, comprising: output means for outputting an output value for confirming the backlash amount of the robot based on the relative movement amount detected by the movement amount detection means. 2. A robot provided with a motor for driving a movable part via a speed reduction mechanism, and a position detection means arranged on the motor side with respect to the speed reduction mechanism for detecting the position of the movable part. In the robot controller, one of a reference device having at least two inner wall surfaces facing each other and a displacement detector having a contact insertable between the inner wall surfaces of the reference device is provided in the movable part of the robot,
The other of the displacement detector is fixed to the fixed portion, and the displacement detector and the reference device are relatively moved in the forward and reverse directions, and the displacement detector is moved by the relative movement in the forward and reverse directions. A movement amount detecting means for detecting that the contactor has contacted two inner wall surfaces of the reference device which face each other, and for detecting the relative movement amount of the displacement detector and the reference device at this time by the position detecting means. A determination means for determining whether or not the robot continues to be used based on the relative movement amount detected by the movement amount detection means and a predetermined reference value; and an output for outputting the determination result by the determination means. And a robot controller. 3. A robot having a motor for driving a movable part via a speed reduction mechanism, and position detection means arranged on the motor side of the speed reduction mechanism for detecting the position of the movable part. In the robot controller, one of a reference device having at least two inner wall surfaces facing each other and a displacement detector having a contact insertable between the inner wall surfaces of the reference device is provided in the movable part of the robot,
The other of the displacement detector is fixed to the fixed portion, and the displacement detector and the reference device are relatively moved in the forward and reverse directions, and the displacement detector is moved by the relative movement in the forward and reverse directions. A movement amount detecting means for detecting that the contactor has contacted two inner wall surfaces of the reference device which face each other, and for detecting the relative movement amount of the displacement detector and the reference device at this time by the position detecting means. A robot control apparatus comprising: a correction unit that corrects a command value that controls the robot based on the relative movement amount detected by the movement amount detection unit. 4. The output value of the output means is a center value of two inner wall surfaces facing each other of the reference device or a distance between two inner wall surfaces facing each other of the reference device. The robot controller according to 1. 5. The determination means determines whether or not to continue using the robot by comparing the shipping data of the robot with the relative movement amount detected by the movement amount detection means. The robot controller according to claim 2, wherein