JPH0346250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-dimensional curved surface machining apparatus using a robot that cuts appropriate locations on a three-dimensional curved surface.

Generally, in structures with complex curved surfaces, such as the body of a passenger car, it is not always possible to press the curved surfaces together, so the parts made by pressing are connected and integrated by electric welding or electric beam welding. , and may also be filled with solder. Traditionally, it has not been possible to process such three-dimensional workpieces as desired using industrial robots, and this has been done manually, so automation is necessary in terms of work environment, pollution, etc. It is said that However, such connecting parts such as formed parts or welded parts on curved surfaces have complicated shapes, and the position, height, or width of the connected parts such as welded parts from the base surface of the workpiece are not constant. Therefore, when processing workpieces flowing on a line with industrial robots,
In general, this industrial robot is controlled to move between positioned points at a constant speed, so it can be controlled to move at a constant speed between positioned points. However, there were drawbacks such as not being able to obtain an ideal machined surface, damaging the base surface, and resulting in an insufficient amount of processing. Furthermore, if the position and orientation of the workpiece is not accurately controlled with respect to the position of the bead, there is a problem of damaging the base surface. Furthermore, since this machining tool moves while maintaining contact with the three-dimensional workpiece, there is a problem in that it is not easy to control the torque of the machining tool with respect to the workpiece.

The present invention solves the drawbacks and problems of these conventional processing devices using robots.

The present invention provides three methods by placing a machining tool on the arm of an industrial robot whose speed trajectory is controlled, controlling the speed trajectory of the machining tool accurately, and controlling the positional relationship between the machining tool and the workpiece. In addition to accurately following the workpiece on a dimensional curved surface, it also controls the amount of work per hour on the workpiece on a three-dimensional curved surface to avoid damaging the base surface of the workpiece or causing problems when the amount of work is insufficient. , an object of the present invention is to provide an apparatus for forming a smooth three-dimensional curved surface on a workpiece.

The present invention uses a sensor system to detect positional deviations, posture deviations, undulations, etc. of a three-dimensionally curved workpiece, and corrects basic data based on such information, so that the robot part and processing tool can accurately process the workpiece. In addition to being able to process parts,
It is an object of the present invention to provide a three-dimensional curved surface machining device that can accurately remove waviness by changing the machining torque and tool rotation speed according to the waviness of a workpiece.

Furthermore, the present invention allows the arm of the robot to move to the vicinity of the workpiece at high speed using the PTP mode in which the position and speed are set in advance. Since the workpiece is machined by controlling the speed trajectory on the machined part, the overall machining time can be shortened, and
By keeping the rotation speed of the machining tool constant and controlling the torque of the motor of the machining tool based on a pre-stored torque pattern that corresponds to the waviness of the workpiece, the amount of machining can be adjusted according to the waviness of the workpiece. It is an object of the present invention to provide a three-dimensional curved surface machining device that can be controlled and machined into a smooth three-dimensional curved surface without waviness.

The three-dimensional curved surface machining device according to the first invention [described in claim 1] includes a robot body having a movable arm,
a memory that stores a position command representing a trajectory in which the arm should move in correspondence with a machining point passing through the final finished surface of the workpiece obtained by a dimension measuring machine or manual operation, and a movement speed command on the trajectory; , the trajectory of the arm is controlled by a servo based on the position command read from the memory, and the speed command from the memory is added to the deviation between the target position and the actual position of the arm based on the position command. a robot control device having a speed trajectory control device that controls the speed trajectory of the arm by performing feedforward control to match the actual trajectory of the arm and the speed on the trajectory to a target trajectory and the target speed on the trajectory; a processing tool disposed at the end of an arm of the robot main body whose speed trajectory is controlled so as to be movable relative to the arm; a processing means having a processing control device capable of controlling the amount of processing per time of the processing part of the three-dimensional curved surface by the processing tool by controlling the positional relationship between the processing tool and the processing part, The arm moves over the workpiece by the speed trajectory control, and a smooth three-dimensional curved surface is formed by controlling the amount of work per time on the workpiece by the processing tool placed on the arm. shall be.

In the configuration of the first aspect of the present invention, first, a position command indicating a target trajectory in which the arm of the robot should move in correspondence with a machining point passing through the final finished surface of the workpiece is generated in advance by a three-dimensional measuring machine or by manual operation. A moving speed command for the target on the trajectory is created, and these command values are stored in a memory. The robot is
The trajectory of the arm is controlled by the servo based on the position command read from the memory, but at this time, the speed command read from the memory is calculated based on the deviation between the target position of the arm given as a command value and the actual position of the arm. By adding and performing feedforward control, the responsiveness of the servo system is increased, and velocity trajectory control is performed so that the actual trajectory of the arm and the speed on the trajectory match the target trajectory and speed.

Here, feedforward control means that according to a predetermined operation and temporal schedule,
Unlike sequence control, which automatically advances the work steps one by one, and feedback control, which returns the control amount and subtracts it from the target value to make the control amount match the target value, the target is the control amount that is predicted by some operation in advance. This is a control method that improves the characteristics of the control system (especially control delay, etc.) by adding it to the value.

In other words, when a heavy object such as a processing tool is placed at the end of the arm, simply giving the arm's target position, or trajectory, as a command value will cause a delay in arm movement due to the inertia of the arm end, making it difficult to accurately reach the target value. do not follow. Therefore, in the present invention, feed forward control is performed by adding the target speed to the deviation between the actual position of the arm and the target position, so that the locus and speed of the arm are controlled to the target value.

Note that the position of the arm is generally expressed in the robot's reference coordinate system (i.e., a coordinate system fixed on the ground) or the respective coordinate systems of each movable part of the robot's arm, and both can be converted into each other. .

On the other hand, at the end of the arm, a machining tool as a machining means is disposed movably relative to the arm, and the machining tool operates based on its rotational speed, that is, based on the deviation between the preset target rotational speed and the actual rotational speed. By moving with respect to the arm, the positional relationship between the processing tool and the workpiece is controlled. Note that the target rotation speed can be set in advance for each location depending on the shape of the part to be processed. Since the speed and trajectory of the arm are controlled as described above, the machining tool is controlled at the end of the arm whose speed trajectory is controlled, and furthermore, the position is controlled between the arm and the workpiece, and the workpiece In addition to accurately tracing the machining process, the amount of machining per hour is controlled according to the rotation speed of the machining tool.

And, the three-dimensional curved surface machining device of the first invention,
Since feedforward control is performed based on speed, it has the advantage of improving the accuracy of the trajectory of the robot's arm. The three-dimensional curved surface machining device of the present invention controls the positional relationship between the machining tool placed on the arm of the robot and the workpiece based on the rotational speed of the machining tool, which accurately controls the speed trajectory. In addition to being able to trace the surface of the workpiece with high precision, it is also possible to control the amount of machining per hour on the workpiece, so the surface shape of the workpiece can be adjusted without damaging the base surface of the workpiece or causing insufficient machining. smooth 3 according to
It has the advantage of being able to form a dimensional curved surface.

The three-dimensional curved surface machining device of the second invention [as described in claim 3] includes a robot body having a movable arm, and a final finish of a processed part obtained in advance by a three-dimensional measuring machine or manual operation. A memory that stores a position command representing a trajectory in which the arm should move in correspondence with a processing point passing through a surface and a movement speed command on the trajectory; In addition to controlling the trajectory, the actual trajectory of the arm and the speed on the trajectory are controlled by adding the speed command from the memory to the deviation between the target position and the actual position of the arm based on the position command to perform feedforward control. a robot control device having a speed trajectory control device that controls the speed trajectory of the arm by making it match a target trajectory and a target speed on the trajectory; and an end of the arm of the robot main body that is subject to speed trajectory control. A processing tool is arranged movably relative to the arm, and the processing tool is moved relative to the arm based on the rotation speed of the processing tool to control the positional relationship between the processing tool and the workpiece, a processing means having a processing control device capable of controlling the amount of processing per time of a three-dimensional curved surface of a workpiece by a processing tool; and a sensor system comprising a sensor that detects waviness, and a signal processing circuit that converts the signal from the sensor into a signal for correcting the position command and the feedforward control of the speed, By equipping the robot controller with a correction function that allows correction of position commands and speed feedforward control in response to correction signals from the sensor system, the influence of positional deviations, posture deviations, and waviness of the workpiece can be reduced. It is characterized in that it provides compensation.

In carrying out the above invention, the following aspects may be adopted. The second invention is one in which a sensor system is added to the first invention, and the following description will focus on the differences from the first invention.

The sensor system consists of a sensor placed on the robot's arm and a signal processing circuit. Prior to machining with a tool, the sensor detects positional shift, posture shift, and waviness of the processed part as the arm moves. Here, the longitudinal positional deviation and angular deviation of the machined part with respect to the pre-stored target locus of the robot are called positional deviation and posture deviation, respectively, and the height of the machined part from the final finished surface and its height. These spatial changes are called height and undulation, respectively.

The signal processing circuit converts the robot's position command and speed feedforward control command value into a signal for modifying the command value based on the signal from the sensor. Then, in response to the signals from the signal processing circuit, the robot corrects the target trajectory and moving speed on the trajectory corresponding to the positional deviation, posture deviation, height, and undulation of the workpiece, and moves based on the position command. The arm's velocity trajectory is controlled by servo control and velocity feedforward control. If the height of the workpiece is uniform, the amount of machining per time can be controlled to be constant by keeping the target rotation speed of the processing tool constant; if the workpiece has undulations, By changing the target rotation speed of the machining tool according to the waviness, the amount of machining per time can be variably controlled.

That is, the second invention is directed to the positional deviation of the processed part,
Since it corrects the three-dimensional trajectory of the robot's arm, that is, the machining tool, according to posture deviation and surface shape, it enables highly accurate machining without damaging the base surface or insufficient machining amount. It has the advantage of

The three-dimensional curved surface machining device according to the third aspect of the present invention [recited in claim 8] includes a robot body having a movable arm, and a final part to be machined obtained in advance by a three-dimensional measuring machine or manual operation. A memory that stores a position command indicating a trajectory that the arm should move in correspondence to a processing point passing through the finished surface and a movement speed command on the trajectory, and a PTP that is set based on the position command read from this memory. a mode switching device that outputs a mode signal and a speed locus mode signal set in the pattern of the position command and speed command, and switches between the two mode signals near the workpiece; At the same time, the actual trajectory of the arm and the speed on the trajectory are controlled by adding the velocity command to the deviation between the target position and the actual position of the arm based on the position command to perform feedforward control. The speed trajectory of the arm is controlled by matching the target trajectory and the target speed on the trajectory, and the
a robot control device having a speed trajectory control device that controls a plurality of axes of the arm so that the arm is moved close to the workpiece in response to a PTP mode signal and moves over the workpiece in response to the speed trajectory mode signal; a robot; a machining tool disposed at the end of an arm of the robot main body whose speed trajectory is controlled so as to be movable relative to the arm; a machining means having a machining control device capable of controlling the amount of machining per time of a three-dimensionally curved surface to be machined by the machining tool by controlling the positional relationship between the tool and the to-be-worked part; A smooth three-dimensional curved surface is formed by moving the arm over the workpiece by trajectory control and controlling the amount of work per time on the workpiece by a processing tool placed on the arm. .

In controlling the movement of the arm of the robot, the third invention switches between a PTP (point-to-point) mode and a velocity trajectory mode similar to the first and second inventions in the vicinity of the workpiece. ,
Avoid approaching or leaving the workpiece.
This is performed using PTP control, and speed trajectory control is performed during machining of the workpiece. That is, the arm moves from a point away from the workpiece to a point near the workpiece stored in the memory at a robot feed rate determined by the distance between the two points under PTP control. At this time, since PTP control is used, the trajectory between two points is not controlled. Then, the PTP control mode is switched to the velocity trajectory control mode at a point near the workpiece, and as in the first and second inventions,
The arm is controlled in velocity trajectory based on the position command and velocity command stored in the memory, and moves on the target trajectory at the target velocity. In addition, in the third invention, the arm is composed of multiple axes, and if the position command is expressed in the robot's reference coordinate system, the command value is converted to the coordinate system of each axis to calculate the position of the arm. Control each axis.

The third invention is such that the movement of the arm of the robot to the vicinity of the workpiece is performed at a position and speed set in advance.
This can be done quickly using the PTP mode signal.
Since the speed trajectory mode signal is switched to the speed locus mode signal near the workpiece, the speed trajectory is controlled over the workpiece, and the workpiece is machined by the machining tool, so that the overall working time can be shortened.

The three-dimensional curved surface machining device according to the first aspect of the first invention [described in claim 2] is characterized in that the robot
A device that samples position information corresponding to the trajectory of the arm that is fed back via a feedback loop at a constant cycle, calculates speed based on two consecutive position information, and applies speed feedback control to the position servo. It is.

Further, in the three-dimensional curved surface machining apparatus according to the first aspect of the second invention [as described in claim 4], similarly to the first aspect of the first invention, the robot Position information corresponding to the trajectory of the arm that is fed back by the arm is sampled at regular intervals, the speed is calculated based on two consecutive position information, and speed feedback control is applied to the position servo.

Both the first aspect of the first invention and the first aspect of the second invention improve the followability of the robot's servo system by applying speed feedback to the robot's position servo using the speed calculated from position information. It has the advantage of being able to increase Also, compared to using a tachometer generator,
It has the advantage of simple structure and low cost.

The three-dimensional curved surface machining apparatus according to the second aspect of the second invention [as set forth in claim 5] is such that the sensor system includes a scanning device that scans the sensor along a predetermined trajectory corresponding to the part to be machined. This is what I did.

The second aspect has the advantage that by scanning the workpiece with a sensor in a zigzag pattern, a single sensor can simultaneously detect positional deviation, posture shift, and waviness of the workpiece.

The three-dimensional curved surface machining device according to the third aspect of the second invention [described in claim 6] is characterized in that the robot
Based on the signal output from the sensor system, the speed on the machining trajectory in the direction along the workpiece is controlled according to the waviness of the workpiece, thereby removing the waviness of the workpiece. .

In the three-dimensional curved surface machining control device according to the fourth aspect of the second invention [claim 7], the machining means controls the robot through an actuator that reciprocates in a direction substantially perpendicular to the surface to be machined. placed on the arm,
When the arm of the robot moves along the machining path along the workpiece, the actuator brings the machining means closer to the workpiece using position control, and then uses torque control to control the workpiece so that the torque is constant for a certain period of time. The positional relationship is controlled according to the undulation of the object, and the object is then evacuated by position control.

This fourth aspect has the advantage that when the machining tool contacts the workpiece, the contact can be made smoothly without generating vibrations, and machining can be started.

Hereinafter, the present invention will be explained in detail based on a three-dimensional curved surface machining apparatus according to an embodiment.

FIG. 1 shows a first embodiment of the apparatus according to the first aspect of the first invention and the third invention, in which a memory 1 stores information about the final finished surface of the workpiece based on the values detected by the three-dimensional measuring machine. Create a mathematical model of a certain grinding surface,
By calculating the positions of M points on the trajectory of this grinding surface and the surface normal vector, the tool held in the robot's arm contacts the workpiece at a preset position and orientation. In this case, calculate the position and orientation of the corresponding robot arm end, and store the encoder values corresponding to the robot joint angles to realize the position and orientation of this robot arm end in the Cartesian coordinate system OR set on the robot base. are doing. In addition, when first storing data in the robot in teaching mode, that is, in the case of manual operation, the robot is moved to point i (i=
1 to M) respectively, take the data of this i point, calculate the posture vector of the grinder in the X, Y, and Z directions for each point, and interpolate between points i and i+1 to create an evenly spaced image on the trajectory. The position of point j (j = 1 to N),
The posture is calculated, and the encoder value _i and its differential value _i corresponding to the joint angle of the robot that realizes this position and posture are stored in the memory 1. Note that the figure shows only one axis of the robot's arm. The encoder value read from the memory 1 is input to the velocity trajectory control device 2.

In the speed trajectory control device 2, two adjacent encoder values _i and _i+1 are divided into N equal parts, and ( _i+1 −
A signal such that _ij = _{i +} j・( _i+1 − _i )/N (where i = 1...M, j = 1...N) is output so that E i )/N is output N times at every fixed time ΔT. occurs. Therefore, after the time ΔT×N, the output of the speed trajectory control device 2 becomes _i+1 ,
Since the next target value _i+2 is read out from memory 1, signals _i+1,j are generated in the same manner as above. In addition, in order to improve the response of the servo system, the differential value _i of the encoder value is read out from memory 1 as a feedforward signal, and 1/N
After being multiplied, it is added to the output _ij of the speed trajectory control device 2 and output as a speed trajectory command value. The signal is amplified by amplifier 3, and D/
The A converter 5 converts it into an analog signal and sends it to the robot 6.
input to the servo amplifier 7. This servo amplifier 7 amplifies the input signal, operates a servo valve 8, drives a cylinder 9, moves the robot 6 to a position specified by the signal, and operates a grinding machine 11 of a grinding device 10 as a processing means. into a certain position. The operating position of this cylinder 9 is determined by the encoder 13.
and is fed back via the feedback circuit 14 of the interface. In this manner, the position and orientation of the grinding device 10 of the robot 6 are sequentially controlled by the position and orientation signals sequentially read out from the memory 1. In this embodiment, in the robot trajectory indicated by P in Fig. 2, PTP is not reached until position _P2 .
The robot 6 is moved by the control to the grinding position P ₂ to _{P 11.}
Until then, the trajectory and speed of the robot 6 are controlled.

With the robot configured as above, grinding machine 1
When grinding the welded part of the workpiece 12 by rotating the tool, for example, if there is a deviation in the direction perpendicular to the surface between the surface of the workpiece and the preset grinding point of the tool, the tool may become separated from the workpiece to be ground,
On the other hand, if you get too close, there is a risk of damaging the object to be ground. In order to avoid this drawback, even if there is a deviation between the tool grinding point and the surface of the workpiece in the direction perpendicular to the surface,
A grinding machine 1 in which a grinding tool follows the surface of a workpiece and grinds at a constant grinding torque and constant grinding rotation speed.
1 torque control will be explained. First, the grinding device 10
A hydraulic motor 17 that rotates the grinding machine 11, a first servo valve 18 that controls the rotation speed of the motor 17,
A detector 19 that detects the rotation speed of the grinding machine 11, a hydraulic cylinder 20 and a piston 21 that move the grinding machine 11 back and forth with respect to the object to be ground 12, and this piston 2.
1, and a potentiometer 23 that detects the position of the grinding machine 11.
This control signal to the grinding tool is generated by the signal generator 16 in response to instructions from the sequence controller 15, which also issues a read command to the encoder memory 1 at the same time.

In Figure 2, the tool is initially at position P ₁ ;
In response to a start instruction from the sequence controller 15, it moves to position _P2 in PTP mode. Moves from position P ₂ to position P ₁₁ using speed trajectory control,
PTP again from position P ₁₁ to the end position of position P ₁₂
Move in mode. Upon reaching position P ₂ , first,
A torque setting signal T _i is sent from the signal generator 16 to the first servo valve 18, and the hydraulic motor 17 adjusts the constant current characteristics of the hydraulic motor and servo valve system using the oil pressure sent from a hydraulic source (not shown). It rotates at no-load rotation speed on the curve (see Figure 3). In this embodiment, this torque setting signal T _i is set to have a constant grinding torque pattern shown in FIG. 2. That is, as described later, in FIG. 3, the current I ₀
The torque is determined by controlling the rotational speed according to a certain characteristic curve. The signal generator 16 is
Next, an ON signal and an OFF signal are sent to relay A, and the hydraulic cylinder 20 is operated in position control mode. The signal generator 16 then sends a position command signal X _i to the servo amplifier 24, which is amplified and sent to the servo valve 22, so that the grinding machine 11 is set at a predetermined position. When the robot moves further and the grinding point reaches position _P3 in FIG. Operating in control mode, the signal generator 16 then generates a rotational speed setting signal n _i which is compared with the actual rotational speed signal of the grinding machine 11 from the detector 19 and the difference signal is the PID The signal is input to the servo amplifier 24 via the servo amplifier 24. That is, when the rotation speed setting signal n _i is larger than the actual rotation speed n, it means that the torque of the grinding machine 11 is larger than the target torque, and in that case, the grinding machine 11
Move the grinding machine 11 in the direction away from the workpiece 12 to match the target rotation speed n _i , and if the rotation speed setting signal n _i is small, move the grinding machine 11 toward the workpiece 12 to match the target rotation speed n i Match n _i .

The device of this embodiment is applied to the work of grinding solder mounds. In this case, the base surface is made of a material that is difficult to grind, such as steel, and the object to be ground is welded to the base surface. It is a soft material such as solder. That is, since the target torque is set to a magnitude sufficient to grind soft materials, the base surface will not be damaged even if the rotation speed is controlled as described above.

By configuring as described above, the grinding machine 11
Since the welded part of the object to be ground 12 is ground at a constant torque and a constant rotational speed on the characteristic curves of the hydraulic motor and the servo valve, the object to be ground can be smoothly ground. After the grinding is completed, the set locus of the tool grinding point moves away from the surface to be ground from position P _f to position P _i0 to position P _ii . On the other hand, the hydraulic cylinder 20
Since the displacement control is performed, the position of the hydraulic piston deviates significantly from the set position, and when it is detected that the amount of positional deviation of the hydraulic cylinder 20 exceeds a certain value, the control method of the hydraulic cylinder 20 is changed. from the rotation speed control method to the position control method. This switching is performed near the position P _i0 in FIG.

This embodiment performs feedforward control based on speed, so the accuracy of the trajectory of the robot's arm is improved.
It has the advantage that the object to be ground can be patterned with high precision. In addition, since the grinding device used as a processing means grinds at a constant torque and constant rotation speed, it has the advantage that it can uniformly grind the object to be ground and does not damage the base surface due to excessive grinding. .

Furthermore, the grinding machine is first brought close to the workpiece by position control, then switched to torque control,
Since it is held for a certain period of time and then retracted by position control, it has the advantage that when the grinding machine comes into contact with the object to be ground, no vibration is generated and grinding can be started smoothly.

FIG. 4 shows an apparatus according to a second embodiment of the present invention, in which the same parts as in FIG. 1 are denoted by the same reference numerals.
The explanation will be omitted. In this embodiment, an electric motor 25 is used in place of the hydraulic motor 17 of the first embodiment, so the operation of this motor 25 is different. Further, 26 is a motor control device, 27 is a power supply device, 29 is a frequency-voltage converter, and 31 is a motor 2
5 and the transmission mechanism of the grinding machine.

Next, the device of this embodiment will be explained based on its operation. First, the signal generator 16 outputs the position signal X _i and the relay signal A, the hydraulic cylinder 20 is position-controlled, and the position signal X _i is amplified by the servo amplifier 24 and input to the servo valve 22. The signal from the potentiometer 23 sets the grinder 11 at an appropriate position. Next, the rotation speed setting signal n _i from the signal generator 16 is input to the adder 28, where the rotation frequency detector 19 and the frequency-voltage converter 2
The drive voltage of the power source 27 is controlled so that the rotation speed of the motor matches the target value. The rotation of this motor 25 is
It is transmitted to the grinding machine 11 via the transmission mechanism 31.

Next, from position P ₃ in Fig. 2, hydraulic cylinder 2
0 is switched from position control to torque control,
It is done as follows.

When the signal generator 16 sends an off signal to relay A and an on signal to relay A, and outputs a target setting torque signal T _i , the hydraulic cylinder 20 enters the torque control mode and controls the drive current of the motor 25 to be constant. be done. That is, the torque T of the motor 25
is always compared with a predetermined target setting torque T _i , and the difference signal is input to the servo amplifier 24, and if the torque of the motor 25 is large, the grinding machine 11
If the torque of the motor 25 is small, move the grinding machine 11 toward the workpiece 12, and move the grinding machine 11 away from the workpiece 12.
1, the welded part is ground more.

As is clear from the above explanation, since the motor is simultaneously controlled by two control loops, the speed control circuit and the torque control circuit, stable grinding is possible.

The operation of this embodiment and the operation of the above-mentioned embodiments differ only in that the position of the grinding machine 11 is determined by a torque signal or by a rotational speed signal, and in addition to the above-mentioned operations. The same effects as in the first embodiment are achieved.

Next, the first aspect of the first invention and the first aspect of the second invention
A description will be given based on the third embodiment of the three-dimensional curved surface machining apparatus belonging to the fourth to fourth aspects and the third invention.

The apparatus of the third embodiment differs from the above-mentioned embodiments in that it includes a sensor system for detecting positional deviation and waviness of the part to be ground, and a robot controlled by signals detected by the sensor system.
It consists of a torque-position control system as a processing means placed on the arm of the robot.

FIG. 5 mainly shows the robot part of the apparatus according to the third embodiment of the present invention. First, data on the trajectory to be moved by the robot and trajectory correction coefficient data are transferred from the paper tape to the memory through the robot sequence controller 102. 101. This paper tape data is obtained by measuring the position to be ground and representative positions on the surface around it using a three-dimensional measuring device, creating a surface using a computer, and then calculating the outer surface on the trajectory of that surface. The line vector is calculated, the obtained position on the trajectory and the external normal vector at that point are converted into the robot's joint angle and angular velocity, and then converted into the robot's encoder value, which is the data representing the position _i. and,
It includes data _i expressing speed and data j〓 _i ^-1 expressing a trajectory correction coefficient. Here, the number of data points i is variable in the range of 1 to m depending on the length of the trajectory, and the data _i and _i correspond to the number of axes of the 6-degree-of-freedom robot, including 6 O, T, D, B, R,S
It is a vector with an axial component. In other words, in the case of a 6-degree-of-freedom robot with 6 joints, the above position data is the joint angle vector (θ _p ,
θ _T , θ _D , θ _B , θ _R , θ _S ), and on the other hand, the matrix T 〓 representing the end position and posture of the arm is the robot's reference coordinate system XYZ and the coordinate system _{t t} at the end of the arm. It is expressed as follows using _t and the position of the end of the arm P _t =(P _t (X), P _t (Y), P _t (Z)) in the robot's reference coordinate system.

T = x _t 0y _t 0z _t 0P _t 1 = x _t (X)y _t (X)z _t (X)P _t (X) x _t (Y)y _t (Y)z _t (Y)P _t (Y) x _t (Z) y _t (Z) z _t (Z) P _t (Z) 0 0 0 1 Then, these joint angle vectors and position
The posture matrix T〓 is all known values and can be exchanged with each other. j〓 _i ^-1 is a coordinate system in which the locus of the grinder grinding point created by actually operating the robot is set as the grinder grinding point,
This is an inverse Jacobian matrix that shows how many bits the encoder values of the six axes of the robot need to be corrected in order to shift the robot by 1 mm in the direction shown in Figure 7 or to tilt it by 1 degree around the x, y, and z axes. has dimensions of Further, the memory 101 stores position data _P , _S , and _l shown in FIG. These indicate the parking position where the robot is at rest, the start point position and the end point position of the grinding trajectory, respectively, and the grinding trajectory L ₂ where the actual grinding is performed.
In contrast, the robot's arm is driven along the final finished surface of the object to be ground ₁₂₃ by speed and _trajectory control, whereas point-to- _point (PTP) ) control, speed commands ( _S − _P ), ( _P − _l ) and ( _S − _l ) given by position deviation in the servo system
This is position data for moving the robot at high speed according to a speed pattern created from Here, the trajectory _L4 is such that the grinder draws a distance from the object 123 to be ground due to the PTP control.
Although Fig. 6 shows the case of unidirectional grinding represented by the trajectory L ₂ for the object to be ground 123, when performing bidirectional grinding, speed and trajectory control are performed on the trajectory corresponding to the trajectory L ₂ . It is also possible to move back and forth.

Next, the robot sequence controller 102
When the sensing mode signal (SM) is sent to the sensor sequence controller ₁₆₈ shown in _FIG . Grinder 1 shown in Figure 8
The 24 grinding point trajectories correspond to the shape and direction of the object to be ground.
The robot sequence controller _{102 shown} in _FIG .
1 as deviation correction data. At this time,
At the same time, the height G _4i (i=1 to m) to be ground in the direction of the object to be ground shown in FIG. 8 is also stored. The operation of the sensor system will be described later. In addition, the robot's operation in sensing mode is exactly the same as in grind mode, which grinds the object to be ground, except that the trajectory data is modified and the robot's feed rate along the trajectory is constant. Therefore, it is omitted.

Hereinafter, the robot sequence controller 102 shown in FIG. 5 has already stored trajectory data _i , _i , correction coefficient data j〓 _i ^-1 and deviation amounts G ₁ , G ₂ , G ₃ in the memory 101 as well as the grinding height G. Assuming that _4i is stored, only the operation on the robot side when the robot sequence controller 102 issues a grind mode signal (GM) will be described first.

Next, the operation of the robot of the third embodiment will be explained. The robot is currently at parking position _P in FIG. 6, and returns to parking position _P once the series of operations is completed. First, in Figure 6,
During PTP trajectory L ₁ , sensing mode (SM)
Regardless of the time or grind mode (GM),
The robot sequence controller 102 reads only the position data _S stored in the memory 101 and outputs it to the adder 103. As a result, the deviation _S - _P between the starting point _S and the current position _x = _P (because it was stopped at the parking position) is output to the robot servo 110RS through the subtracter 110, and the robot receives PTP control until it reaches the starting point of the grinding trajectory. It works. And the grinder 124
At the same time that the grinding tooth flank position reaches the starting point _S , the robot sequence controller 102 sends a grind mode signal (GM) to the torque position control system shown in FIG. In this torque position control system, as will be described later, upon receiving a grind mode signal (GM), the grinder 124 is moved to the object 12 to be ground in a preset pattern.
3 in the direction shown in FIG. 7, and at the moment when the speed coincides with a predetermined set speed n ₀ (corresponding to the torque), a logic signal v _c =“1” is sent to the robot sequence controller 102 . The robot sequence controller 102 receives this logical signal v _c = "1" and sequentially divides the velocity trajectory data _i from the memory 101 to start grinding along the grinding trajectory _L2 shown in FIG. The position locus data _i is sent to the adder 105, and the locus correction coefficient data j〓 _i
^-1 and the deviation amounts G _i , G ₂ , G ₃ are read out to the multiplier 104, and the grinding height G _4i (i=1 to m) is read out and set in the arithmetic unit 107 that calculates the average division number N ₀ . Ru. The computing unit 107 outputs N ₀ to the computing unit 108 which computes M as the number of times of grinding, and the computing unit 108 sets the number of grindings M in a counter inside the robot sequence controller 102 . As a result, the robot sequence controller 102
After the robot has created M grinding trajectories, new data is no longer read from the memory 101.
Finish a series of actions.

On the other hand, the output N ₀ of the arithmetic unit 107 is obtained from the arithmetic unit 107 that calculates the actual number of trajectory divisions N _i along the trajectory.
, and its output N _i becomes one input of the divider 105. Therefore, if the output of the divider 105, that is, the feed rate along the trajectory _i /N _i is high according to the undulation of the grinding height, then You can see that it's slow, and the lower it is, the faster it is. This feed rate _i /N _i is multiplied by the adjustment coefficient ₃ for the 6 axes of the robot, and then the multiplier 1
The output ( _i / _Ni )* ₃ of 11 is added to the adder/subtractor 113 as a speed term for feedforward control.

On the other hand, the multiplier 104 calculates the amount of correction Δ of the position along the trajectory. That is, ∆=∆E ₁ ∆E ₂ ∆E ₃ ∆E ₄ ∆E ₅ ∆E ₆ = j〓 _i ^-1・Positional deviation in the x direction Positional deviation in the y direction Positional deviation in the z direction Tilt around the x axis Tilt around the y axis Z axis The change Δ in the encoder value of each joint of the robot can be obtained from the relationship of circumferential slope=j〓 _i ^-1 ·G ₁ G ₂ 0 0 G ₃ 0. That is, if the positional deviations G ₁ and G ₂ and posture deviation G ₃ of the object to be ground in the orthogonal coordinate system are known, the corresponding deviation Δ in the coordinate system of each joint of the robot can be determined. This correction amount Δ becomes the input of the adder 103, _i + Δ
is output to the DDA calculator 109 as new position data. The DDA calculator 109 uses the trajectory division number N _i of data i and data i-1 as the other input, and calculates the position data between i and i-1 as _ij at a constant cycle, for example, 10 ms. The number of calculations is N _i , and the positions of _i and _i-1 are linearly interpolated to create intermediate position data. This position data _ij is output to the subtracter 110 as a position term for feedforward control, and becomes the target position. Further, the subtracter 110 creates a negative feedback control loop between the position of each axis of the robot monitored by the encoder 122 and the current position of the robot converted into a binary value _x by the gray binary converter 120, _ij − _x is output, multiplied by each axis adjustment coefficient ₄ by the multiplier 112, and the feed forward speed term and the adder/subtractor 113 produce ( _i /N _i ) *
( ₃ + ( _ij − _x ) * ₄ is created. Also, the subtracter 115 subtracts the binary value _x of the encoder and the output _c of the delay compensation calculator 117 to create the actual speed of each axis servo. Axis adjustment coefficient ₅ multiplier 11
By using the output ( _x - _c )* ₅ multiplied by 4 as the subtraction input of the adder/subtractor 113, the followability of the servo system is compensated.

Through the digital calculations described above, all the deviations needed to create appropriate trajectories for each of the robot's six axes and servos have been calculated, so this is converted into an analog quantity by the D/A converter 116, and then the servo amplifier 118
The power is amplified and output to the servo valve 119,
Drive the cylinder 121 of the 6-axis robot,
The trajectory of the grinder grinding point attached to the robot hand is controlled according to the position of each axis, and the feed rate of the grinder tooth surface along that trajectory is controlled according to the grinding height of the object to be ground to eliminate waviness. are doing. In this way, when the grinder grinding tooth surface reaches the end point of the trajectory, position E _l in FIG. 6, the robot sequence controller 102 again reads out the trajectory start point data _S in FIG. The trajectory L ₄ is returned to the starting point E _S by PTP control, and the above-mentioned series of operations is repeated.
When the operation reaches M times, the robot returns to parking _P on the trajectory _L3 in FIG. 6 under PTP control, stops, and finishes the grinding work on the curved surface. At that time, the coefficient K ₂ set in the arithmetic unit 108
is determined by two limiting conditions: the grinding capacity of the grinder and the appropriate grinding work time, and can be adjusted so that the grinding work is completed within a desired time.

From the above, the deviation amount G ₁ from the sensor system,
Based on the data of G ₂ , G ₃ and grinding height G _4i (i = 1 to m), the trajectory data originally stored by the robot is
By correcting _i and _i , controlling the feed rate according to the grinding height, and determining the grinding work time from the average grinding height and the grinding capacity of the grinder, it is possible to prevent positional deviations, posture deviations, and grinding of the object to be ground. Even if there is an undulation in height, the curved surface grinding work can be completed within the set time.

FIG. 7 shows a torque position control system as a processing means of the third embodiment of the present invention, and 136 is provided at the arm end 133 of a robot having degrees of freedom of five or six axes or more. This device 136 is equipped with a hydraulic motor 134 and an electric/hydraulic servo valve 135.
(Hereinafter, the electric/hydraulic servo valve is simply referred to as an electro-hydraulic servo valve) is driven with a constant current I ₀ to control the oil pressure supplied from the oil pressure source 137, and the torque rotation speed characteristic of the known servo valve 135 is controlled. It operates on a curve (see Figure 3). The rotational force of this hydraulic motor 134 is transmitted to the grinder 12 through a transmission mechanism 128.
4. The rotation speed of this grinder 124 is determined by the rotation speed detector 125 as a pulse train output n _P (t)
Detected as . In addition, the grinder control device 1
36 is provided with a hydraulic cylinder 130, and a piston 12 provided inside this hydraulic cylinder 130.
The shaft ends 131, 131' of 9 are the robot arm ends 13.
3 is fixed to a frame 132 provided in the hydraulic source 13.
The grinder 124 is operated by the hydraulic pressure supplied from the robot arm end 1 through the electro-hydraulic servo valve 127.
33 as a reference and moves back and forth with respect to the object to be ground 123. Further, the relative position of the grinder 124 with respect to the robot arm end 133 is determined by the potentiometer 1.
26 and outputs x _P (t).

Next, the operation of this torque position control system will be explained. As mentioned above, the robot sequence controller 102 moves the robot along the trajectory shown in FIG.
When the grinder 124 is moved to the starting point _S of the grinding trajectory by PTP control during _L1 , a grind mode signal (GM) is generated. In this torque position control system, this grind mode signal (GM)
In response, the target rotation speed n ₀ of the grinder 124 is output to the subtractor 142 through the target rotation speed setting device 148 . At the same time, constant current setting device 141 outputs constant current I ₀ to servo valve 135, thereby
The grinder 124 has a rotational force transmission system (servo valve 13
5, hydraulic motor 134, rotational force transmission mechanism 128)
Electro-hydraulic servo valve 135 with current I ₀ as a parameter
The motor rotates at the maximum rotation speed corresponding to zero torque on the torque rotation speed characteristic curve. This rotation is converted into a pulse train n _P (t) by the rotation speed detector 125,
Furthermore, it is converted into an analog voltage value n(t) by a frequency-voltage converter 138 and output to a subtracter 142 and a comparator 149. This comparator 149 is n
(t) and n ₀ are constantly compared, but even once n
If (t)n becomes ₀ , its logical output signal v _c
operates to hold the "1" level. In this case, the grinder 124 grinds the object 1 to be ground.
Since there is no contact with 23, n(t)>n ₀ ,
Comparator 149 sends logic signal v _c =“0” to relay 150
Output. The relay 150 has a logic signal “1”
There is one make contact A 0 which closes if the value is " ₀ " and opens if the value is "0", and two break contacts ₁ and 2 which close the contact if the value is "0" and open if the value is "_1" . Therefore, immediately after the grind mode signal (GM) is issued, the grinder 124 is not in contact with the object to be ground, and the contact 145 is in the OFF state.
Contacts 146 and 147 are in the ON state. Since the grind mode signal (GM) is also issued to the position pattern generator 151 at the same time, the position pattern generator 151 is outputting x ₀ (t). In this case, the adder/subtractor 143 is connected to the position pattern generator 1 by the contacts 146 and 147.
The target position signal x ₀ (t) from the potentiometer 126 is added to the positive side, and the current position signal x _P (t) of the grinder 124 from the potentiometer 126 is added to the negative side.
x ₀ (t) - x _P (t) is output to the servo amplifier 140, which amplifies the power and outputs it to the servo valve 127, so a position control loop with x ₀ (t) as the target value is established. ○

Claims (1)

[Claims] 1. A robot body having a movable arm, and the arm should move in accordance with a machining point passing through the final finished surface of the workpiece obtained in advance by a three-dimensional measuring machine or manual operation. A memory that stores a position command representing a trajectory and a movement speed command on the trajectory, and a servo that controls the trajectory of the arm based on the position command read from the memory, and controls the trajectory of the arm based on the position command. By adding the speed command from the memory to the deviation between the target position and the actual position and performing feedforward control, the actual trajectory of the arm and the speed on the trajectory are made to match the trajectory of the target and the target speed on the trajectory. a robot control device having a speed trajectory control device for controlling the speed trajectory of the arm according to the method of the present invention; By controlling the positional relationship between the machining tool and the workpiece by moving the machining tool relative to the arm based on the rotation speed of the machining tool, the speed per time of the workpiece on a three-dimensional curved surface by the machining tool is controlled. a machining means having a machining control device capable of controlling the amount of machining, the arm moves over the workpiece part by the speed trajectory control, and the workpiece part is moved per hour by the machining tool disposed on the arm. A three-dimensional curved surface machining device is characterized in that it forms a smooth three-dimensional curved surface by controlling the amount of machining. 2. The position servo of the robot control device samples position information corresponding to the trajectory of the arm fed back via the feedback loop at a constant cycle, and calculates the speed based on two consecutive position information, 2. The three-dimensional curved surface machining apparatus according to claim 1, wherein speed feedback control is applied to said position servo. 3. A robot body with a movable arm, a position command indicating a trajectory along which the arm should move corresponding to a machining point passing through the final finished surface of the workpiece obtained in advance by a three-dimensional measuring machine or manual operation, and A memory for storing a movement speed command on the trajectory, and a servo based on the position command read from the memory to control the trajectory of the arm, and to adjust the target position and actual position of the arm based on the position command. The velocity trajectory of the arm is controlled by adding the velocity command from the memory to the deviation of the velocity and performing feedforward control to match the actual trajectory of the arm and the speed on the trajectory to the target trajectory and the target speed on the trajectory. a robot control device having a speed trajectory control device; a processing tool disposed at an end of an arm of the robot body whose speed trajectory is controlled so as to be movable relative to the arm; By controlling the positional relationship between the processing tool and the workpiece by moving the processing tool relative to the arm based on a processing means having a processing control device; a sensor disposed on the arm of the robot body to detect positional deviation, posture deviation, and waviness of the processed part; and a signal processing circuit for converting the feedforward control of the speed into a signal for correction, and the robot control device is provided with a position command and a feedforward control of the speed according to the correction signal from the sensor system. A three-dimensional curved surface machining device, characterized in that it has a correction function that enables control correction, thereby compensating for the effects of positional deviation, posture deviation, and waviness of a processed part. 4. The position servo of the robot control device samples position information corresponding to the trajectory of the arm fed back via the feedback loop at a constant cycle, and calculates the speed based on two consecutive position information, 4. The three-dimensional curved surface machining apparatus according to claim 3, wherein speed feedback control is applied to said position servo. 5. The three-dimensional curved surface machining apparatus according to claim 3, wherein the sensor system includes a scanning device that scans the sensor along a predetermined trajectory corresponding to the part to be machined. 6. The robot control device controls the speed of the machining trajectory in the direction along the workpiece according to the waviness of the workpiece, based on the signal output from the signal processing circuit. The three-dimensional curved surface processing apparatus according to claim 3, characterized in that the undulations are removed. 7. The processing means is disposed on the arm of the robot via an actuator that reciprocates in a direction substantially perpendicular to the workpiece surface, and when the arm of the robot moves along the workpiece along the workpiece trajectory, the actuator moves After the processing means is brought close to the workpiece by position control, the positional relationship is controlled according to the waviness of the workpiece by torque control so that the torque is constant for a certain period of time, and then it is withdrawn by position control. A three-dimensional curved surface machining device according to claim 6, characterized in that the three-dimensional curved surface machining device is configured as follows. 8 A robot body having a movable arm, and a position command indicating a trajectory in which the arm should move in correspondence with a machining point passing through the final finished surface of the workpiece obtained in advance by a three-dimensional measuring machine or manual operation, and A memory for storing a movement speed command on the trajectory, a PTP mode signal set based on the position command read from this memory, and a speed trajectory mode signal set based on the pattern of the position command and speed command. The device includes a mode switching device that outputs and switches between the two mode signals near the workpiece, and controls the trajectory of the arm by a servo based on the position command, and also controls the target position and actual position of the arm based on the position command. The speed trajectory of the arm is controlled by adding the speed command to the deviation from the position and performing feedforward control to match the actual trajectory of the arm and the speed on the trajectory to the target trajectory and the target speed on the trajectory. and a robot control device having a speed trajectory control device that controls a plurality of axes of the arm so that the arm is moved close to the workpiece in accordance with the PTP mode signal and moves over the workpiece in accordance with the speed trajectory mode signal; a processing tool disposed at the end of an arm of the robot main body whose speed trajectory is controlled so as to be movable relative to the arm; and moving the processing tool relative to the arm based on the rotational speed of the processing tool. a processing means having a processing control device capable of controlling the amount of processing per time of the processing part of the three-dimensional curved surface by the processing tool by controlling the positional relationship between the processing tool and the processing part. , the arm moves on the workpiece by the speed trajectory control, and a smooth three-dimensional curved surface is formed by controlling the amount of processing per time of the workpiece by the processing tool disposed on the arm. Characteristic three-dimensional curved surface processing equipment.