JPH1124721A - Robot controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a smooth curvilinear track for a robot with a small pieces of representative points, to obtain improved production efficiency and reduced operator's labor, and to secure long-period robot life and improve the track precision. SOLUTION: An operator instructs 2n pieces of representative points through an input device 2 and combinations of pairing up the instruction points Pi are generated. Then the pitch of a track generated between paired instruction points is indicated and the controller 2 divides the part between the combined instruction points by a division number (m) calculated from the pitches to generate intermediate points Pjk. Then interpolating tracks La, L1...Lb connecting between the respective instruction points and between the respective intermediate points are generated and connected together by curves and arcs in order to generate an operation track. When the robot 5 is put into actual operation, the controller 2 generates the operation track by following the procedure and controls the operation of the robot 5 according to it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot controller for generating an operation trajectory by interpolating between taught representative points and operating a robot according to the operation trajectory.

[0002]

2. Description of the Related Art Conventionally, in a teaching reproduction type robot control, when a robot reproduces a curved trajectory, a representative point of each straight line is taught as a set of short straight lines, and the curved trajectory is represented by a set of short straight trajectories. Instead, it was to be played.

[0003]

In the above-described conventional robot control, in order to reproduce a smooth curve trajectory, the curve is subdivided into a number of finer straight lines, and a number of representative points corresponding thereto are taught. I needed to. For this reason, conventionally, there has been a problem that a long time is required for teaching and production efficiency is reduced.

Further, if the actual motion trajectory during reproduction is inappropriate, it is necessary to correct the position of each teaching point.
Since this correction is equivalent to correcting the positional relationship between a number of short straight lines, the number of correction steps is large, and it takes a long time and is complicated. Also, from this point, especially in the case of remote teaching, the operator performs a long-time work near the operating robot. Had to be performed, which required a great deal of effort.

On the other hand, on the robot side, if a curved trajectory is reproduced by a set of short straight trajectories, there will be discontinuities in speed and acceleration in the motion trajectory. A heavy load is applied to the movable part of the robot, and the motion trajectory becomes vibratory. For this reason, the conventional robot control has a problem that the life of the robot is shortened and the trajectory accuracy is reduced.

The present invention has been made in view of such circumstances, and enables a robot to reproduce a smooth curved trajectory at a few representative points, shortens the time required for teaching and trajectory correction, and improves production efficiency. An object of the present invention is to provide a robot control device which can improve the operation and reduce the labor of the operator, and can secure a long-term robot life and improve the trajectory accuracy by gradually changing the operation speed and acceleration. And

[0007]

The invention according to claim 1 (for example, see FIG. 2) comprises input means for inputting a representative point of a trajectory for operating a robot and various instruction data,
In a robot controller for generating an interpolation trajectory connecting the representative points and operating the robot according to the interpolation trajectory, the input representative points (P1 to P8) are combined two by two, and the combined representative points (P1 and P5, P1 and P6, P3 and P7, and P4 and P8), respectively, a first calculating means for generating intermediate points (P11, P12,..., P64) which internally divide by a predetermined number; A first interpolation trajectory (La) connecting one of the representative points and a second interpolation trajectory (Lb) connecting the other of the combined representative points are generated, and the first interpolation trajectory (La) is sequentially located from each of the representative points. And a second calculating means for sequentially generating new interpolation trajectories (L1 to L6) between the first and second interpolation trajectories by sequentially setting intermediate points as new representative points.

According to a second aspect of the present invention (see, for example, FIG. 7), in the robot controller according to the first aspect, each of the interpolation trajectories (L1 to L1) generated by the second arithmetic means is provided.
L4), the representative point (P1 to P8) and the intermediate point (P1
, P12,..., P24) along with division points (Q11, Q13,
, Q46), and the interpolation points (L'1 to L'8) different from the interpolation paths are set as the representative points (the intermediate points) and the division points as new representative points (Q10 to Q47). It is characterized by further comprising a third calculating means for generating.

According to a third aspect of the present invention, in the robot controller according to the first or second aspect, the first arithmetic means combines representative points in accordance with instruction data input from the input means. .

According to a fourth aspect of the present invention, in the robot control apparatus according to any one of the first to third aspects, each of the interpolation trajectories is determined by an order specified by instruction data input from the input means. It is characterized by being generated by the following polynomial.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

<1. Configuration> An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a painting robot system to which a robot control device according to an embodiment of the present invention is applied.

In FIG. 1, reference numeral 1 denotes a controller which receives instruction data from an input device 2 via a cable 3 and supplies an operation command signal to each axis (movable portion) of the robot 5 via a cable 4; Various signals are transmitted to and received from the robot 5, thereby monitoring the state of the robot 5 and controlling its operation. This controller 1
Is a storage device that stores a control program, teaching data, various control parameters, and the like of the robot 5, and an arithmetic processing device that performs various arithmetic processes based on the programs and the instruction data and signals received from the robot 5. And determines the operation of the robot 5 based on the result of the arithmetic processing by the arithmetic processing device, and generates the operation command signal. Note that the specific contents of the arithmetic processing here will be described later.

The input device 2 is an input device for an operator to input an instruction for instructing the operation of the robot 5.
The input data is output as the instruction data. Cables 3 and 4 are connection lines for connecting the input device 2 to the controller 1 and connecting the controller 1 to the robot 5, respectively. The cable 3 transmits the instruction data output from the input device 3 to the controller 1, and 4 transmits a signal transmitted and received between the controller 1 and the robot 5.

The robot 5 is a main part of the painting robot in the present painting robot system, and is mounted at a predetermined position on the floor by a box 6 fixed to the factory floor. It is composed of components such as a turning base, each axis driving unit, and an arm as shown. Hereinafter, each of these components will be described.

Reference numeral 7 denotes a first shaft drive unit provided between the box 6 and the turning base 8. The first shaft drive unit 7 is composed of a motor fixed to the box 6 side and a speed reducer or the like provided on the output shaft side thereof. It is attached so that it can rotate in the direction. Then, the first shaft drive unit 7 is driven based on an operation command signal supplied from the controller 1, thereby rotating the turning base 8 in the θ1 direction.

In the upper left portion of the turning base 8 in the drawing,
Similarly, a second shaft drive unit 9 including a motor, a speed reducer, and the like is attached. In the second shaft drive unit 9, a motor is fixed to the turning base 8 side, and its output shaft is connected to one end (rear end) of the first arm 10 via a speed reducer to form a second shaft. ing. Then, the second axis drive unit 9 is driven based on an operation command signal supplied from the controller 1, whereby the first arm 10 is turned in the direction of the arrow θ2 in the drawing.

On the other hand, a third axis drive unit 11 is attached to the other end (forward end) of the first arm 10. Also in the third shaft drive unit 11, the output shaft of the motor is connected to the second arm 12 via the speed reducer to form a third shaft, which is driven based on an operation command signal supplied from the controller 1. , The second arm 12 is pivotally moved in the direction of the arrow θ3 in the figure.

A wrist shaft drive unit case 13 is attached to the second arm 12 at a connection portion (rear end side) with the third shaft drive unit 11, and a first wrist member 14 and a first wrist member 14 are provided at the forward end. A second wrist member 15 and a third wrist member 16 are attached.

The wrist shaft drive unit case 13 includes a drive motor for each of the first wrist member 14, the second wrist member 15, and the third wrist member 16 and a reduction gear for each of those motors. Is stored (not shown). Further, the first wrist member 14, the second wrist member 15, and the third wrist member 16 are sequentially attached via connecting shafts rotatable in directions of arrows θ4, θ5, and θ6 in the drawing. Further, the driving force generated by the wrist axis drive unit is stored in the second arm 12 by θ4, θ5, θ.
As the rotational force in six directions, the first wrist member 14,
A transmission mechanism for transmitting to the second wrist member 15 and the third wrist member 16 is provided.

Then, in the configuration of the wrist portion as described above, the wrist axis drive unit is driven based on the operation command signal supplied from the controller 1, and the first wrist member 14, the second wrist member 15, Third wrist member 16
Are rotated in the directions of θ4, θ5, and θ6, respectively.

Reference numeral 17 denotes a bracket attached to the tip of the third wrist member 16. Reference numeral 18 denotes a coating gun for spraying the coating material in a certain direction with a certain spread, and is attached to the tip of the wrist portion of the robot 5 via a bracket 17. The robot 5 uses this coating gun 18,
Gun tip (reference numeral 18x in the figure) at a position determined by the rotation angles θ1, θ2, θ3, θ4, θ5, and θ6 of the respective axes.
To paint a work (not shown).

That is, in the present painting robot system, the turning base 8, the first arm 10, and the second arm 1
2. The position x of the gun tip 18x of the coating gun 18 and the posture R of the robot 5 at that time, based on the rotation angles θ1 to θ6 of the first wrist member 14, the second wrist member 15, and the third wrist member 16.
(Where, the position x and the posture R are vector quantities. The same applies to the following description). These positions, postures, rotation angles, and the like are determined by arithmetic processing in the arithmetic processing unit of the controller 1, and are controlled by operation command signals to the first to third axis drive units and the wrist axis drive unit based on the determination. Is done.

<2. Operation> (1) Generation of Motion Trajectory from Representative Point Next, the operation according to the above configuration will be described. at first,
An arithmetic processing operation in which the operator teaches representative points on the trajectory where the gun tip 18x should be moved from the input device 2 and the controller 1 generates a trajectory based on these representative points will be described.

Generation of Trajectory Along Curved Surface FIG. 2 is a diagram showing an example of generating a trajectory along a curved surface based on a taught point taught as a representative point. In this figure, a curved surface CS is one surface portion of a work to be subjected to a painting operation, and has a partly smooth stepped shape. Points P1 to P8 indicate taught points (represented by position vectors) taught as representative points of the trajectory for moving the gun tip 18x, and are fixed points suitable for coating with the coating gun 18 from the curved surface CS. It is located at a distance.

As shown in the figure, the trajectory generation corresponds to the curved surface CS
, A plurality of intermediate points (P11, P12,..., P64) indicated by crosses between the trajectory La from the teaching points P1 to P4 and the trajectory Lb from the teaching points P5 to P8. , And a new trajectory (L1, L2,..., L) between the trajectories La and Lb by their midpoints.
6) is to generate. FIG. 3 shows a procedure of such trajectory generation, which will be specifically described below.

First, the operator uses the input device 2 to
× n (n is a natural number) representative points are taught (step S
1). Here, points P1, P2, and P3 where the gun tip 18x moves to the curved surface CS and starts painting work.
And P4 and points P5, P6, P7 and P8 at the end of the painting operation and leaving the curved surface CS. Therefore,
In this case, "n = 4".

Next, an instruction is given to combine teaching points for generating an intermediate point (step S2). This “combination of taught points” refers to a set of two taught points generating an intermediate point therebetween, and a straight line or an arc connecting the two taught points or moving between the two taught points. In this case, the rotation angle of each axis is divided at a predetermined interval to generate an intermediate point (details will be described later). In step S2, the operator selects the combination of the teaching points as appropriate, and instructs the combination of the teaching points to be combined by input from the input device 2.

In this case, unless otherwise instructed by the operator, the controller 1 controls the i-th teaching point Pi.
And the (n + i) -th teaching point Pn + i as a set (step S3). Here, “i” is a natural number from 1 to n, whereby n sets of combinations are generated from 2 × n teaching points. Therefore, in the example of FIG. 2, the teaching points P1 and P5,
A combination of four sets of teaching points P2 and P6, P3 and P7, and P4 and P8 is generated. In the following, for the sake of simplicity, the description will be given taking as an example the combination of the teaching points generated in step S3.

Subsequently, the pitch "pich" of the trajectory generated between the paired teaching points is specified (step S4, FIG. 2).
reference). This corresponds to a predetermined interval for generating the above-mentioned intermediate point, and is determined by an operator according to the paint spray width of the paint gun 18 and the like, and is instructed by inputting from the input device 2.

Next, at the controller 1, the teaching point P1
The distance L between the distance and the teaching point Pn + 1 is calculated (step S
5) Thereafter, the number of divisions m for dividing the set of teaching points is obtained as m = (L / pich + 0.5) (step S6). Here, the decimal part on the right side of the above equation is rounded off so that the value of the division number m is obtained as a natural number. It should be noted that “+0.5” is used so that “m × pich” is less than the distance L (the remainder does not occur when the interval between teaching points is divided by m for each pitch “pich”). This is to raise the value of m when the decimal part of “L / pich” is less than 0.5. This allows
The number m of divisions in the example of FIG.

Based on the division number m obtained in this way, for each combination of the teaching points, the teaching point is divided to generate an intermediate point. In this process, the connected teaching points are connected by straight lines l1, l2, l3, and l4 (see FIG. 2), and the internal dividing point that divides these straight lines into m equals from the trajectory La side by Lb.
This is performed by sequentially obtaining the sub-points on the side, and setting the obtained subdivision points as the intermediate points (steps S7 and S8). Specifically, the internally dividing point of the j-th straight line lk counted from the trajectory La side,
That is, the intermediate point Pjk

(Equation 1) Asking. Note that the counter “j” is a natural number from 1 to m−1 (here, 6), and the counter “k” is a natural number from 1 to n (here, 4).

As a result, the intermediate points P11, P12,..., Pjk,..., P64 indicated by crosses in FIG. 2 are sequentially obtained. Here, as shown, the trajectory from the intermediate point P11 to P14 is determined. The trajectory from L1, P21 to P24 is L2, ..., P61 to P
The trajectory toward 64 is L6, etc.
And trajectories La, L1, L
Consider moving the gun tip 18x along these in the order of 2,..., L6, Lb. The trajectories La and Lb are considered to correspond to the trajectories with the counters “j” of “0” and “7”, respectively.

In this way, the trajectories L1, L3, L5 and Lb (L7) in which "j" is an odd number are turned trajectories. Thus, if the counter "j" is odd,
Proceeding from step S9 to step S10, a process of changing the order of the intermediate points (or teaching points) is performed (step S10).
11). In this process, the controller 1 temporarily stores the data of the point Pjk in the buffer as shown in the figure, and then replaces the data of the point Pjk with the data of the point Pj (n + 1-k).
The replacement process of replacing the data of j (n + 1-k) with the data temporarily stored in the buffer is performed by sequentially changing the value of k from 1 to n / 2.

By the above processing, the teaching point P1 shown in FIG.
→ P4, intermediate point P14 → P11, P21 → P24, ..., P61 → P6
4. Representative points of the trajectory for moving the gun tip 18x in the order of the teaching points P8 → P5 are generated. Then, the process proceeds to a process for obtaining an interpolation formula for interpolating between the representative points generated in this way.

Here, a general time (time) is used for the interpolation formula.
The operator first designates the degree of the order from the input device 2 (step S12). At this time, if there is no instruction from the operator, the order of the interpolation formula is set to n (here, 4) (step S13). The order of the interpolation formula determines the shape (concavity and convexity) of the curved trajectory generated in the subsequent processing, and is appropriately determined by the operator according to the shape of the work and the like. This is because a curve that always passes through n points in the space is higher than or equal to the nth order, and since the lowest order is the nth order, a curve trajectory that matches the n representative points can be generated.

Subsequently, based on the data of each representative point, the controller 1 obtains an n-th order interpolation formula for each trajectory to generate an operation trajectory of the gun tip 18x (step S14). That is, polynomials representing curves corresponding to the trajectories La, L1 to L6, and Lb in FIG. 2 are obtained, and a curved trajectory represented by them (hereinafter, such a trajectory is referred to as an "interpolated trajectory") is shown in FIG. The motion trajectory for moving the gun tip 18x is generated by sequentially connecting appropriate guns and curved lines.

In the above-described trajectory generation, the number of representative points to be taught is set to 2 × n in advance, and the trajectory between the trajectories of the teaching points P1 to Pn (P4) and the trajectories of Pn + 1 (P5) to P2n (P8) is set. , New trajectories (L1 to L6) are generated, but the number of representative points to be taught in advance is (N or more natural number N) × n, and the trajectories of P1 to Pn and the trajectories of Pn + 1 to P2n , Between the trajectories P2n + 1 to P3n and the trajectories P3n + 1 to P4n,..., P (N−2) n + 1 to P (N−
1) A new trajectory may be generated by the same processing as described above for each of the trajectories of n and the trajectories of P (N-1) n + 1 to PNn.

Generation of Trajectory by Sinusoidal Wave Approximation Next, as shown in FIG. 4, an example of generating a trajectory oscillating in a sinusoidal waveform based on a taught point taught as a representative point will be described. In FIG. 4, although the work is omitted, points P1, P2, and P3 indicate teaching points (represented by position vectors), and a curve (L
s) indicates the generated interpolation trajectory (movement trajectory).
FIG. 5 shows a procedure for generating the interpolation trajectory Ls.

In generating the interpolation trajectory Ls, first, the operator teaches the positions of the points P1 and P2 as the representative points (and the posture of the robot 5 at these positions) using the input device 2 (step S20).

Next, in order to interpolate between these teaching points with a sinusoidal curve, an instruction for specifying the amplitude is issued. This amplitude instruction is performed by instructing points other than the teaching points P1 and P2, thereby instructing the amplitude by the distance from the straight line connecting P1 and P2 to the point, or by inputting the magnitude of the amplitude. The amplitude is directly designated by the length (mm), and a program corresponding to the two types of amplitude designation in the controller 1 is prepared. The operator teaches the position of the point P3 in FIG. 4 when the amplitude instruction is performed in the former mode, and the length (mm) of the amplitude A in the figure when the amplitude instruction is performed in the latter mode. ) Is input (step S21).

Subsequently, the number of cycles of the interpolation between the teaching points P1 and P2 is instructed (step S22). FIG.
In the case of (3), interpolation between teaching points is performed using three cycles of sine waves, so the operator inputs an instruction “vibration cycle number = 3” from the input device 2.

Then, the controller 1 receives this, and internally divides between the teaching points P1 and P2 by the number of vibration cycles to generate an intermediate point (step S23). In the case of FIG. 4, points P10 and P20 indicated by crosses are obtained as internally dividing points, and these are set as intermediate points.

Next, the amplitude A and the angular velocity ω of the approximate sine wave curve connecting the teaching points P1 and P2 are determined (step S).
twenty four). Regarding the amplitude A, when the point P3 is taught in step S21, the distance from the straight line l1-2 connecting the teaching points P1 and P2 to the teaching point P3 is calculated, and the distance is set as the amplitude A.
When the length of the amplitude is directly specified, the length is set to A. On the other hand, the angular velocity ω is determined by the ratio of the operating speed v between P1 and P2, assuming that the length obtained by dividing the distance between the teaching points P1 and P2 by the number of cycles corresponds to 2π.

From the amplitude A and the angular velocity ω determined as described above, an interpolation formula representing an approximate sine wave curve connecting between the teaching points P1 and P2 is also determined, and the interpolation trajectory Ls in FIG. Generated.

(2) Control Operation of Robot 5 Next, the operation of controlling the robot 5 by generating an operation trajectory as described above will be described with reference to FIG. The process shown in FIG. 6 is repeatedly performed at regular time intervals. Here, the constant time means that a signal such as the current position of the gun tip 18x and an operation command signal are exchanged between the controller 1 and the robot 5. Sampling time (T
s) corresponds to this. In the painting robot system, the processing shown in FIG. 6 is performed by the arithmetic processing unit of the controller 1 at every sampling time of 5 ms.
The target position of 8x and the target posture of the robot 5 are calculated, and each axis is controlled.

In the following, a counter (time counter) for each sampling time for calculating the target position and the like of the gun tip 18x is represented by "count". The teaching point (P1, P2,..., P8) and the intermediate point (P1
1, P12,..., P64), the ones at both ends of each interpolation trajectory (P1, P4, P14, P11, P21, P24, etc.) are collectively referred to as "playback points", and they are passed through in the order of passage during playback. The attached counter is represented by “k”. Accordingly, in the example of FIG. 2, the reproduction point P1 is k = 1, P4 is k = 2, and P14 is k.
= 3,..., P64 is k = 14, P8 is k = 15, P5 is k =
16, a playback point where k = 1 is the starting point of the motion trajectory;
k = 16 corresponds to the reproduction point which is the end point of the motion trajectory.

In FIG. 6, first, the rotation angle θ of each axis is sent from the robot 5 to the controller 1 via the cable 4.
Signals indicating 1 to 6 are supplied, and the arithmetic processing unit in the controller 1 takes in the signals as the rotation angle feedback values of each axis (step S30). Then, based on the value of the rotation angle of each axis taken in, the gun tip 18x
Of the robot and the posture of the robot 5 (step S3
1). Note that these positions and postures can be calculated as a function of the rotation angles θ1 to θ6 of each axis by a geometrical method.

Subsequently, after incrementing the time counter "count" by 1 (step S32), the counter co
The current time t is obtained by multiplying unt by the sampling time Ts (step S33).

Next, it is determined whether or not the gun tip 18x has reached the final point of the interpolation trajectory (step S34). In this determination, when the value of the time t obtained in step S33 exceeds the final time Te in the moving interpolation trajectory, it is determined that the time has arrived; otherwise, it is determined that the time has not reached. When it is determined that the trajectory has been reached, the process proceeds to step S35 and subsequent steps for generating the next interpolation trajectory. Note that the "final time Te" is calculated at the same time as calculating the interpolation formula for generating the interpolation trajectory in step S35 and subsequent steps (step S42 in the figure; details will be described later). In the initial stage of the operation 5, an appropriate initial value is set so that the process proceeds from step S34 to S35 even if the value of t is small and the process for generating the interpolation trajectory is performed.

In step S35, the reproduction point counter k is incremented by one. At this time, the counter k is incremented immediately after it is determined that the gun tip 18x has reached the final point of the interpolation trajectory. Therefore, the reproduction point corresponding to the counter k at this point corresponds to the reproduction point where the gun tip 18x has moved and is currently located.

If the value of the counter k exceeds the value (k = 16) corresponding to the end point of the motion trajectory, "k =
Set the playback point counter to 1 "as the starting point of the motion trajectory (P1)
(Steps S36 and S37. The meaning of this processing will be clarified later).

Then, the end point of the interpolation trajectory for moving the gun tip 18x next is determined by adding 1 to the current counter k (step S38). That is, since the reproduction point corresponding to k incremented in step S35 is the current position of the gun tip 18x, the reproduction point corresponding to k + 1 becomes the end point of the next interpolation trajectory. The reproduction point corresponding to the end point is obtained.

If the value of k + 1 exceeds the value (k = 16) corresponding to the end point of the motion trajectory, the end point of the next interpolation trajectory is set to the reproduction point corresponding to k = 1, that is, the motion trajectory. The start point (P1) is set (steps S39 and S40. The meaning of this process will be clarified later).

Next, an interpolation formula is calculated based on the interpolation information between the reproduction points at both ends of the next interpolation trajectory determined through the processing of steps S35 to S40 (step S41).
Here, the interpolation information includes the position data of each representative point and each generated intermediate point input by the operator, the operation speed between each representative point, the degree of the polynomial when interpolating by a polynomial, and a sine wave approximation curve. And the like when interpolation is performed, and corresponds to various data input or calculated in “(1) Generation of motion trajectory from representative point” and stored in the storage device.

That is, in step S41, the controller 1 performs an interpolation represented by a polynomial, trigonometric function, arc or the like by the processing shown in FIG. 3 or FIG. The formula is determined.

Subsequently, the process proceeds to step S42 to calculate a transition time Te required for movement between the reproduction points. This can be calculated from the interpolation formula obtained in step S41 and the specified speed and acceleration limit values. Then, in step S43, the value of the time t is cleared, and in step S44, the value of the time counter count is also cleared. Thus, the calculation of the interpolation formula when the reproduction point is reached and a series of processes associated therewith are completed. Proceed to step S45.

Here, the transition time Te of the next interpolation trajectory newly generated is calculated by the above-described processing, and
The time t and the value of the time counter “count” are cleared, and the counting is newly performed again from the next steps S32 and S33.
Accordingly, since the value of the transition time Te represents the final time in the interpolation trajectory with respect to the time t, the comparison in the transition time Te enables the determination in step S34.

In steps S39 and S40, k +
When the value of 1 exceeds the value corresponding to the end point of the motion trajectory, the end point of the next interpolation trajectory is set as the start point of the motion trajectory. Thus, in step S41, the start point (P5 in FIG. 2) is changed from the end point of the motion trajectory. An interpolation formula for going to P1) is obtained. In other words, this case corresponds to the case where the painting work on the work is completed. In order to perform the painting work on the next new work, the interpolation trajectory for moving the gun tip 18x again to the start point of the operation trajectory is set. It is generated.

On the other hand, in steps S36 and S37, if the value of the counter k exceeds the value corresponding to the end point of the motion trajectory, the reproduction point counter is returned to the start point of the motion trajectory by setting "k = 1". As a result, in step S41, an interpolation equation for moving from the start point (P1) of the motion trajectory to the next reproduction point (P4) is obtained again. That is,
This case corresponds to the case where the gun tip 18x returns to the starting point of the operation trajectory again after the processing of steps S39 and S40 is performed as described above. An interpolation trajectory for moving the gun tip 18x again from the start point of the operation trajectory is generated in order to start the painting work on the work.

The processing for generating the interpolation trajectory is performed in this way. In step S45, the target position of the gun tip 18x and the target posture of the robot 5 are calculated by substituting the value of the current time t into the interpolation formula. . Then, a control amount for each axis is calculated based on the target position and target posture and the current position and posture calculated in step S31 (step S46), and an operation command signal corresponding to the control amount is output to the first position. First to third
The power is supplied to the shaft drive unit and the wrist shaft drive unit (step S47). As a result, the robot 5 is controlled so as to operate according to the trajectory as shown in FIGS.

(3) Another form of motion trajectory generation Next, another form of the motion trajectory generation performed by the controller 1 will be described.
Note that the motion trajectory generation described below can be similarly used in the above “(2) Control operation of robot 5”, and the robot 5 can be operated according to the trajectory generated thereby.

FIG. 7 shows how the trajectory is generated according to the present embodiment. In this figure, as in FIG. 2, the curved surface CS shows one surface portion of the work having a stepped shape, and points P1 to P1
P8 indicates a teaching point taught as a representative point.

As shown, in this trajectory generation, first,
By the same processing as in FIG. 3 described above, intermediate points (P11, P12,..., P24) indicated by crosses in the figure are generated, and temporary interpolation trajectories L1 to L4 represented by polynomials are generated. And furthermore
On the interpolated trajectories, new representative points (Q20, Q30,...) Indicated by ◎ in the figure are generated, and the final points intersecting the interpolated trajectories L1, L2, L3, and L4 based on these representative points. , L'8 are generated. FIG. 8 shows a specific procedure of such trajectory generation.

In FIG. 8, the processing in steps S50 to S58 is the same as the processing in FIG. 3 described above. That is, first, the operator teaches 2.times.n representative points using the input device 2 (step S50), and then instructs connection of the teaching points for generating an intermediate point (step S51).
It is assumed here that n = 4 and eight representative points P1 to P8 are taught (see FIG. 7). When there is no instruction from the operator, the i-th teaching point P
The process proceeds by combining i and the (n + i) th teaching point Pn + i (step S52).

Subsequently, in step S53, the pitch "pich" of the trajectory generated between the paired teaching points is specified. This "pich" is the interpolation trajectory L'1 to be finally generated.
The trajectory pitch of the provisional motion trajectories L1 to L4 that intersects L8. Here, after calculating the distance L between the teaching point P1 and the teaching point Pn + 1 (step S54), m = (L / pich + 0.5) is rounded off using the designated "pich". It is assumed that the divided number m is 3 (step S55).

Based on the division number m obtained in this way, the straight lines (the above-mentioned straight lines l1, l2, l
3, l4. Here, the illustration is omitted because it becomes complicated).
Internal dividing points to be equally divided are obtained, and the obtained internal dividing points are set as intermediate points (steps S56 and S57). The equation for calculating the internal dividing point used here is the same as the above equation 1, but since the counter j is from 1 to 2 and k is from 1 to 4, the intermediate point is indicated by a cross in FIG. 8 of P11-P14 and P21-P24 shown
Individuals will be obtained.

Then, the process proceeds to a step S58, where temporary interpolation trajectories L1, L2, L3 and L4 are generated. Here, FIG. 9 shows a more detailed description of the processing contents after step S58, and is also referred to below (in FIG. 9, steps corresponding to the steps in FIG. Number). In step S58, a tentative interpolation trajectory Li (i = i = i) is obtained by obtaining a polynomial representing a curve indicated by a dashed line in FIG. 7 from the generated intermediate point and teaching point by the same processing as steps S12 to S14 in FIG. 1
To 4) are generated (step S58 'in FIG. 9). However, here, since these are not necessarily the interpolation trajectories to be finally obtained, the above-described replacement processing and the processing for connecting the interpolation trajectories are not performed.

Next, the number of divisions l for dividing each temporary interpolation curve Li by trajectory is specified (step S59,
S59 '). Since the division number 1 determines the final interval and number of the interpolation trajectory according to this number, the operator decides so that the painting work of the curved surface CS can be appropriately performed,
An instruction is given by inputting from the input device 2. FIG. 7 shows a case where the number of divisions 1 is designated as 7.

Thereafter, the controller 1 receives the instruction of the number of divisions 1 and divides each interpolation trajectory Li by 1 to generate a new representative point (step S60). In this process, i = 1 to
For each interpolation trajectory Li up to m + 1 (the number of temporary interpolation trajectories, in this case, 4) (step S60'a), by equally dividing the representative points (teaching points or generated intermediate points) on the interpolation trajectory, The interpolation trajectory is l by each equidistant point and each representative point.
Make it split. In FIG. 7, the equally-divided points (new representative points) generated here are indicated by で marks.

That is, first, with respect to the interpolation trajectory L1, equally divided points Q11 and P2 which divide the teaching point P1 and P2 into two equal parts.
An equally-divided point Q13 that divides between 2 and P3 into two equal parts, and equally-divided points Q15 and Q16 that divides between P3 and P4 into three equal parts are obtained.
In the example shown in FIG. 7, since the distance between the teaching points P3 and P4 is relatively long compared to the other points, this is divided into three equal parts so that the interpolation trajectory L1 is divided into l (7) as a whole. ing.

At this time, at the same time, for convenience of the subsequent processing,
A number is assigned to each teaching point and each equally dividing point in order from the teaching point P1 side. Although this number is indicated by a suffix of the code Q in FIG. 7, a code in which a code is added to the code Q is assigned to all representative points as shown in the figure, and the code is hereinafter referred to as appropriate. . That is, for each teaching point, a code Q10 is assigned to P1, Q12 is assigned to P2, Q14 is assigned to P3, and Q17 is assigned to P4. Representative points on the interpolation trajectory L1 are Q10, Q11,.

Next, similarly, for the interpolation trajectory L2,
Equal points Q21, P12 that bisect the middle point P11 and P12
Q23, which divides between P13 and P13 into two equal parts, and Q25 and Q26, which divide three times between P13 and P14, are respectively obtained.
Q24 is assigned to P13 and Q27 is assigned to P14, and representative points on the interpolation trajectory L2 are Q20, Q21,..., Q27.

For the interpolation trajectories L3 and L4, equally-divided points are sequentially generated in the same manner as described above, and codes Q30 to Q30 are assigned to respective representative points.
Q37 and Q40 to Q47 are assigned. Thus, all the representative points Qij (i = 1 to 4, j = 0 to 7) shown in FIG. 7 are determined (step S60'a).

Subsequently, the process proceeds to step S61, where the generated representative points are connected in a direction intersecting with the provisional interpolation trajectory Li to generate an operation trajectory (step S61). This process is performed as follows using the numbers “i” and “j” of each representative point Qij. In the following, “i” is referred to as a first subscript number, and “j” is referred to as a second subscript number.

As shown in FIG. 9, for each representative point whose second subscript number j is from 0 to 1 (here, 7) (step S61'a), if the value of j is an odd number, A polynomial that connects representative points in order from the smaller subscript number i of 1 to the smaller one (Q4j → Q1j); otherwise, the smaller the first subscript number i from the larger one (Q1j → Q4j). (Interpolation formula) is obtained (steps S61'b, S61'c, S61 ')
d).

That is, first, the representative point Q10 where j = 0.
With respect to .about.Q40, the process proceeds from step S61'b to S61'd, where a polynomial connecting these in the order of Q10, Q20, Q30, Q40 is obtained based on the position data of each point and the like, and the interpolation trajectory L from Q10 to Q40 is obtained. '1 (see FIG. 7). Next, for the representative points Q11 to Q41 where j = 1, the process proceeds from step S61'b to S61'c, where Q41, Q31, Q21, Q11
Then, a polynomial connecting them is obtained in the order of to generate an interpolation trajectory L'2 from Q41 to Q11. Steps S61'c and S6 are similarly performed for j below depending on whether or not the number is odd.
1′d, and the interpolation trajectories L′ 3, L′ 4,.
Generate L'8.

In this way, each interpolation trajectory L'1, L'2,
.., L'7 and L'8 are generated, and sequentially connected by curves or arcs as shown in the drawing, thereby generating an operation trajectory for moving the gun tip 18x.

In the above-described trajectory generation, the number of representative points to be taught is set to 2 × n in advance, and the trajectory between the trajectories of the teaching points P1 to Pn (P4) and the trajectories of Pn + 1 (P5) to P2n (P8) is set. After generating temporary trajectories (L1 to L4), final trajectories (L'1 to L'8) intersecting them are generated. Natural number N) x n, P
Between the orbits 1 to Pn and the orbits Pn + 1 to P2n, P2n + 1 to P3
, P (N-2) n + 1 between the trajectory of n and the trajectories of P3n + 1 to P4n
ＰP (N-1) n and the trajectories of P (N-1) n + 1 to PNn for each of the trajectories in the same manner as described above. It is good also as generating a natural trajectory.

[0079]

As described above, according to the present invention, in a robot controller for generating an interpolation trajectory and controlling the operation of a robot, an intermediate point which internally divides between the combined representative points is generated. First and second interpolated trajectories are generated from one of the representative points and the other, and intermediate points sequentially located from one of the representative points are sequentially newly set as representative points. Since a new interpolation trajectory is sequentially generated in the meantime, it is possible to automatically generate an interpolation trajectory of the same form that complements the interpolation trajectory generated from the representative point. This makes it possible to generate an interpolation trajectory necessary for operating the robot along a curve or a curved surface from a small number of representative points, and has the effect of greatly reducing the time required for teaching and trajectory correction. Can be In addition to this, it is possible to improve production efficiency, and in the case of remote teaching, there is also an effect that the time for performing work near the operating robot is reduced, thereby reducing the operator's labor. can get.

Furthermore, according to the second aspect of the present invention, a point at which each generated interpolation trajectory is divided according to an instruction from the input means is newly set as a representative point, and interpolation trajectories in different modes are generated. As described above, the mode of the interpolation trajectory generated from a small number of representative points can be changed as necessary.

According to the third aspect of the present invention, since the representative points are combined in accordance with the instruction data input from the input means, the operator can appropriately select the position and mode of the newly generated interpolation trajectory. Can be.

According to the fourth aspect of the present invention, since each interpolated trajectory is generated by a polynomial of the degree specified by the instruction data input from the input means, the degree to be specified is changed. Thus, the shape of each interpolation trajectory can be changed. This makes it possible to compensate for the unevenness of the work without changing the position of the representative point, and to further reduce the time required for correcting the trajectory.

Furthermore, in the invention according to the fourth aspect, since the interpolation is conventionally performed by a short straight line, the interpolation is performed by one polynomial.
The load on the movable part of the robot is reduced, and the motion trajectory does not become oscillating. As a result, it is possible to obtain an effect that a long-term robot life can be ensured and that the trajectory accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a painting robot system to which a robot control device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram illustrating an example of generating a trajectory along a curved surface based on a teaching point taught as a representative point.

FIG. 3 is a diagram showing a procedure of trajectory generation in FIG. 2;

FIG. 4 is a diagram illustrating an example of generating a trajectory that vibrates in a sinusoidal waveform based on a taught point taught as a representative point.

FIG. 5 is a diagram showing a procedure of trajectory generation in FIG. 4;

FIG. 6 is a diagram showing an operation procedure for controlling the robot 5 by generating an operation trajectory.

FIG. 7 is a diagram showing a state of another example of trajectory generation.

FIG. 8 is a diagram showing a procedure of trajectory generation in FIG. 7;

FIG. 9 is a diagram showing steps S58 to S61 in FIG. 8 in detail.

[Explanation of symbols]

 1 Controller 2 Input device 5 Robot 18 Painting gun 18x Gun tip

Claims (4)

[Claims] 1. A robot controller comprising input means for inputting representative points of a trajectory for operating a robot and various instruction data, generating an interpolated trajectory connecting the representative points, and operating the robot according to the interpolated trajectory. A first calculating means for combining the input representative points by two points and generating an intermediate point which internally divides the combined representative points by a predetermined number, and a second calculating means for connecting one of the combined representative points. 1 interpolated trajectory and a second interpolated trajectory connecting the other of the combined representative points, and the intermediate points sequentially located from one of the representative points are sequentially newly newly represented as the representative points. A second control means for sequentially generating a new interpolation trajectory between the first and second interpolation trajectories. 2. The robot controller according to claim 1, wherein each of the interpolation trajectories generated by the second calculation means is:
Along with the representative point and the intermediate point, a division point to be divided is determined according to the instruction data input from the input means, and the representative point, the intermediate point, and the division point are newly set as representative points, and are different from the interpolation trajectories. A robot control device further comprising a third calculation unit that generates the interpolation trajectory according to the aspect. 3. The robot control device according to claim 1, wherein the first arithmetic unit combines the representative points according to the instruction data input from the input unit. 4. The robot control device according to claim 1, wherein each of the interpolation trajectories is generated by a polynomial of an order specified by instruction data input from the input means. A robot control device characterized by the following.