JPH0418788Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an industrial robot, and more particularly to an articulated industrial robot.

Conventionally, there has been a painting robot main body in which a painting gun is attached via a joint to the tip of the wrist as the tip of a movable part that is movably attached to a base via a joint, and a coating gun that is to be positioned sequentially. a storage device for storing position data of
PTP (point-to-point) teaching type articulated painting robots are known.

When teaching a painting robot using the PTP teaching method, the position and orientation of the painting gun at a turning point on the trajectory to be painted is taught.
This taught point sequence is sequentially connected during reproduction to generate a reproduction trajectory. In the case of a painting robot, the paint gun has a given length, and the paint is sprayed along its length from its tip, and the paint is sprayed in a predetermined spray pattern. Sometimes, it is necessary to record not only the position of the painting gun, but also the gun's aiming direction and the twist angle of the spray pattern, so it is necessary to record not only the position of the painting gun but also its attitude. The taught position and orientation of the painting gun are stored as a combination of detection values from detectors provided at each joint of the robot. Further, the position of the tip of the paint gun where the paint is injected is given as coordinates viewed from an orthogonal coordinate system fixed such that one axis coincides with the longitudinal axis of the paint gun.

Regeneration in such a painting robot is performed so that the tip of the painting gun reaches a given speed.
At this time, the angular velocity at each joint of the painting robot is determined by the movement time or operation time between the series of teaching points of the robot body, and the gun tip as seen from the coordinate system fixed to the base between successive teaching points i-1 and i. It was calculated from the positional displacement and the given gun tip speed, and determined based on this. In this case, the tip position of the painting gun with respect to the base at each teaching position is determined by the relationship between the coordinate system fixed on the base obtained from the joint angle at each joint and the coordinate system fixed on the painting gun. Based on this, the coordinates seen from the coordinate system fixed on the paint gun are converted into the coordinates seen from the coordinate system fixed on the base.

In the above-mentioned painting robot, the aiming direction and torsion angle as the attitude of the painting gun, that is, the direction seen from the coordinate system fixed to the base of each axis of the coordinate system fixed to the gun, change greatly. If the position of the gun tip itself does not change much, the point at the tip of the wrist that holds the gun changes greatly, but the distance the gun tip moves is short, and the travel time calculated based on this moving distance is ultimately small. I get used to it. A large change in the posture of the painting gun means a large change in the joint angle of each joint of the robot body, but since the travel time obtained is small, the angular velocity of each joint of the robot is very large. In some cases, the operating limits of each joint may be exceeded, or the movement of the robot body may suddenly change at the taught position. In addition, although the tip speed of the painting gun is a given speed, the angular speed around the gun tip is large, so the speed at the base of the gun and the speed of the wrist holding the gun become large, making control difficult. It had the following drawback.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide an industrial robot that can operate smoothly as a whole without increasing the angular velocity of each joint of the robot body too much.

According to the present invention, the above object is to provide a robot body in which a painting gun is attached to the tip of a movable part that is movably attached to a base via a joint, and a coating gun that is to be positioned sequentially. A storage means for storing position data of the gun, and given points in the three axial directions of a three-dimensional orthogonal coordinate system fixed to the painting gun, relative to the reference point of the robot body based on the stored position data. , a first calculation means for calculating the difference between the first position and the second position where the paint gun can move, and a second calculating means for calculating the average distance by averaging the magnitudes of the three differences. This is achieved by an industrial robot having two calculation means and a third calculation means for determining the operating time of the robot body according to the average distance.

According to the above configuration, the movement distance of each given point in the three axial directions of the three-dimensional orthogonal coordinate system fixed to the painting gun is calculated, and the movement of the robot body is calculated using the average of these three movement distances. Since the time is determined, the angular velocity of each joint depends on both the tip position and posture of the painting gun, which prevents the angular velocity of each joint of the robot body from becoming too large and makes it easy to control.
The robot can operate smoothly as a whole, and sudden changes in the movement of the movable parts of the robot body can be avoided.

Next, a coating robot 1 as a preferred example of an industrial robot according to the present invention will be explained based on the drawings.

In the figure, 2 is a 6-degree-of-freedom articulated painting robot body, and the painting robot body 2 is connected to a base 3 placed on the floor and a disk 4a as a joint in the A1 direction with respect to the base 3. A column 5a having a length r1 is connected to the base 3 at the joint 4b so as to be rotatable in the horizontal plane in the vertical plane in the A2 direction, and a column 5a at the joint 4c. The first arm portion 5b is rotatably connected in the vertical plane in the A3 direction, and the joint 4
At d, the second arm section 5c is rotatable in the A4 direction around the axis 6a along the extension direction of the first arm section 5b, and at the joint 4e, the length consists of the first and second arm sections 5b and 5c. The wrist 5e is rotatable in the A5 direction around the axis 6b perpendicular to the rotation axis 6a of the second arm part 5c with respect to the arm 5d of r2.
and a joint 4f located at the tip of the wrist 5e with length r3.
A6 about an axis 6c which is coplanar with axis 6a and extends perpendicularly to axis 6b.
A length attached to the wrist 5e so as to be rotatable in the direction
R4 painting gun 5f. 7a is a hydraulic drive device that rotationally displaces the column 5a in the A1 direction with respect to the base 3, 7b is a hydraulic drive device that rotationally displaces the column 5a in the A2 direction with respect to the base 3, and 7c is a hydraulic drive device 7b. The arm 5 cooperates with the pillar 5a.
Hydraulic drive device for rotationally displacing d in the A3 direction, 7
d is the second arm portion 5c with respect to the first arm portion 5b.
Hydraulic drive device that rotates and displaces in the A4 direction, 7e
7f is a hydraulic drive device that rotationally displaces the wrist 5e in the A5 direction with respect to the arm 5d, and 7f is a hydraulic drive device that rotationally displaces the painting gun 5f in the A6 direction with respect to the wrist 5e.
When a,..., 7f are collectively referred to, they are represented by the symbol 7).

8a is a detector that detects the rotation angle B1 of the support 5a in the A1 direction with respect to the base 3, 8b is a detector that detects the rotation angle B2 of the support 5a in the A2 direction with respect to the base 3, and 8c is a detector that detects the rotation angle B2 of the support 5a with respect to the base 3 in the A2 direction. 8d is a detector for detecting the rotation angle B3 in the A3 direction, 8d is a detector for detecting the rotation angle B4 in the A4 direction of the second arm portion 5c relative to the first arm portion 5b, and 8e is the arm 5
A detector detects the rotation angle B5 of the wrist 5e in the A5 direction with respect to d, and 8f is the paint gun 5 with respect to the wrist 5e.
This is a detector that detects the rotation angle B6 of f in the A6 direction (hereinafter, the detectors 8a, . . . , 8f are collectively referred to as 8).

Here, the angles B1, B2,...B6 are defined as the X0 axis of the three-dimensional orthogonal coordinate system X0, Y0, Z0 fixed on the base 3, and the three-dimensional orthogonal coordinate system X1 fixed on the disk 4a,
Coincide with the X1 axis of Y1, Z1, and further align with the X2 axis of the three-dimensional orthogonal coordinate system
The three-dimensional orthogonal coordinate system X6, Y6, Z6 fixed at f
Each corresponding joint 4a when aligned with the X6 axis,
4b,...4f, the X0Y0 plane is parallel to the floor, and the X0 axis is parallel to the extension direction of the arm 5d of the robot body 2 in the state shown in FIGS. 1 and 2. , X1, Y1, Z1 coordinate systems are initially coincident with the X0, Y0, Z0 coordinate systems, and the X2, X3, ... Assume that it matches the direction. Of course, the X, Y, and Z axes may be arranged differently. Here, the reference point 0 of the robot body 2 is
It corresponds to the origin of the X0, Y0, Z0 coordinate system, and corresponds to the intersection of the rotation center of the joint 4b and the rotation center of the disk 4a. For example, the nozzle tip 5 of the painting gun 5f
If the degree of freedom is relatively large for g, the reference point is 0.
For example, a given point fixed to the support column 5a may be selected as the point.

Reference numeral 9 denotes a handle, 9a a teaching instruction switch, and 10 a memory device. During teaching, a person holds the handle 9 and performs a pseudo painting operation on the object to be painted, and by pressing the switch 9a as appropriate, the robot at that time can be programmed. Detector 8 detects the attitude of main body 2
The detected angle data B1, . . . B6 are sequentially stored in the storage device 10 for each teaching point i.

11 is a coordinate transformation calculator, and under the control of the control device 12, the calculator 11 converts each teaching point i.
A set of data B1 stored in the storage device 10 for each
...Based on B6, find a conversion matrix Ti for converting the position data seen in the coordinate system X6, Y6, Z6 to the position data seen in the coordinate system X0, Y0, Z0.
The coordinate transformation matrix between two orthogonal coordinate systems is
When U, V, W, and P are each 3x1 vectors, they are expressed as a 4x4 matrix of T=UVWP0001. Here, U, V, and W are the base vectors of each axis of one coordinate system viewed from the other coordinate system, and P is a displacement vector representing the displacement of the origin.

When fixing an orthogonal coordinate system to each joint of a robot and finding a coordinate transformation matrix between each coordinate system, the relationship between the joints is rotation or translation around a certain axis. Therefore, if D is the case of rotation and R is the case of parallel movement, then a coordinate transformation matrix Ti between the coordinate system fixed to the gun and the coordinate system fixed to the base is obtained by the product of D and R. Therefore, Ti is Ti=D1・
It can be found in the form of D2, R1, D3, R2, D4, D5, R3, D6. Here, D1, D2,...D6 are joints 4a and 4, respectively.
The transformation matrices R1, R2, and R3 associated with the rotation of angles B1, B2, and B6 at b,...4f are the given lengths r1, r2, and R3 of the strut 5a, arm portion 5d, and wrist portion 5e, respectively. A transformation matrix representing the parallel movement corresponding to r3, respectively, for example, D1=C1 S1 0 0 −S1 C1 0 0 0 0 1 0 0 0 0 1, D2=C2 0 S2 0 0 1 0 0 −S2 0 C2 0 0 0 0 1 D3=C3 0 -S3 0 1 0 0 S3 0 C3 0 0 0 0 1,0D4=1 0 0 0 0 C4 S4 0 0 -S4 C4 0 0 0 0 1 D5=C5 0 S5 0 0 1 0 0 −S5 0 C5 00 0 0 1, D6=C6 S6 0 0 −S6 C6 0 0 0 0 1 0 0 0 0 1 Rj=1 0 0 0 0 1 0 0 0 0 1 0 rj 0 0 0 (however j=1,2,3). Note that Ck=cosBk Sk=sinBk (k=1,2,…,6).

That is, the coordinate transformation calculator 11 receives the signal E from the control device 12 every time a teaching instruction is given to the control device 12 by the teaching instruction switch 9a, and converts the set of data B1i, just stored in the storage device 10, to the control device 12. ...B6i (generally expressed as Bi) is read out, a conversion matrix Ti is determined based on the data Bi, and after the calculation is completed, a termination signal E is given to the control device 12.

13 is a conversion matrix Ti corresponding to the teaching point i-1 which is one point before the teaching point i.
-1, and is a memory configured to store 14
is the robot body 2 changing from the posture corresponding to teaching point i-1 to the posture corresponding to teaching point i.
Painting gun 5 including changes in the attitude of painting gun 5f
The displacement of f is a fixed point in the coordinate system X6, Y6, Z6
PX (r4, 0, 0), PY (0, r4, 0), PZ (0,
0, r4) with respect to the base 3 (i.e. reference point 0), and the calculator 14 as a first calculation means calculates the calculation given from the control device 12 in response to the signal F. Under the control of the instruction signal G, the conversion matrix data Ti, Ti-1 are read out from the arithmetic unit 11 and the memory 13, and the points PX,
The displacement H of PY and PZ from the first position corresponding to teaching point i-1 to the second position corresponding to teaching point i is HPX=(Ti-Ti-1) r4 0 0 1 HPY=(Ti -Ti-1) 0 r4 0 1 HPZ=(Ti-Ti-1) 0 0 r4 1. Here, the point PX corresponds to the nozzle tip 5 of the coating gun 5f, and HPX represents the displacement vector of the nozzle tip 5g viewed from the coordinate system X0, Y0, Z0 fixed to the base 3.

Note that the arithmetic unit 14 gives a signal J to the controller 12 when the calculations of HPX, XPY, and HPZ are completed. The controller 12 generates a signal K in response to the signal J and outputs a signal K to the arithmetic unit 11.
The conversion matrix Ti obtained by is stored in the memory 13.
be stored in Reference numeral 15 denotes an average moving distance calculator as a second calculation means, and the calculator 15 receives the signal J.
Under the control of the instruction signal L given from the controller 12 in accordance with the calculation results HPX, HPY,
Read HPZ and find the average moving distance d in the form d=1/3 (|HPX|+|HPY|+|HPZ|). Here |HPX|, |HPY|, |
HPZ | is the displacement vector HPX, HPY, HPZ, respectively
The size is determined based on the top three elements of the four elements arranged in 4 rows and 1 column. This average moving distance d is determined not only by the displacement of the nozzle tip 5g of the painting gun 5f with respect to the base 3 but also by the attitude of the painting gun 5f, in other words, the direction of the nozzle of the painting gun 5f or the displacement of the wrist 5e with respect to the base 3. is also dependent. Assuming the displacement of 5g at the nozzle tip | HPX
Even if | is small, wrist 5e at joints 4e, 4f, etc.
When the bending direction or the twist angle in the direction of the hand changes significantly, at least one of |HPY| and |HPZ| becomes a large value, and the average moving distance d becomes a relatively large value.

When the calculation of the moving distance d between the teaching points i-1 and i is completed, the calculation unit 15 sends the signal M to the controller 1.
2, and the controller 12 issues an operation instruction signal N in response to the signal M.

Reference numeral 16 denotes a speed setting device in which the magnitude V of the average movement speed is set, and 17 indicates the time ti-1 of the posture change operation of the robot body 2 from the teaching point i-1 to the teaching point i under the control of the signal N. , i, and the calculator 17 calculates ti−1,i=d/V based on the average distance data d and the set speed data V under the control of the signal N, and calculates the result. travel time data
ti-1,i is given to the controller 12 and stored in the storage device 10 as teaching data.

During playback, the controller 12 controls the travel time ti-
1, i, the teaching data Bi-1, Bi, ti is set so that the posture of the robot body 2 changes from the state of teaching point i-1 to the state of teaching point i.
-1, i and the detection output from the detector 8, the robot body 2 is controlled via the comparator 18, the hydraulic drive device 7, etc.

The calculation of the moving time t may be performed during playback. In this case, this travel time t
The calculation is performed when the robot body 2 is at the teaching point i-
This may be done after the comparator 18 confirms that the teaching point 1 has been reached, but preferably, the robot body 2 is in the process of approaching the teaching point i-1 from the teaching point i-2. , for example, starts at the same time as the comparator 18 confirms that the robot body 2 has reached the teaching point i-2. Furthermore, when creating teaching data by directly inputting the position data Bi from a keyboard or the like, the travel time t may be calculated during input or after the input is completed and stored in the storage device 10 as teaching data. good. Furthermore, the average moving distance d may be stored instead of the average moving time t as teaching data, and in this case, for example, the playback speed can be selected by setting the speed data V as desired at the time of playback.

In the painting robot 1 configured as described above, the moving time t depends not only on the magnitude of the change in the position of the tip 5g of the painting gun 5f but also on the change in the direction of the painting gun 5f, and the displacement of the wrist portion 5e is relatively small. If it is large, even if the displacement amount of the tip 5g of the painting gun 5f is small, it will be a relatively large value, and the robot body 2
There is no risk that movable parts such as the wrist 5e of the user will be rapidly played back.

Also, the wrist 5e between teaching points i-1 and i
When the moving distance of the base of the gun or the tip 4e of the arm 5d is large, the average moving distance d is approximately the same as that of the gun tip 5.
The gun tip 5g can be moved at a substantially uniform speed V, approximately corresponding to the travel distance g.

In the above, the direction or length direction of the nozzle of the painting gun 5f coincides with the X6 axis, and the nozzle tip 5
We explained the example where g is located on X6, but even if the nozzle tip 5g is located on the Y6 or Z6 axis,
It does not have to be located on any axis among X6, Y6, and Z6.

In addition, in the above, the movement distance d or movement time t was determined mainly by taking into account the magnitude of displacement of the tip of the wrist 5e. In the case of having a large degree of freedom, the travel time may be calculated by taking into consideration the magnitude of displacement of the arm part, which is a movable part located in the middle. Furthermore, if the change in the posture of a certain intermediate arm is greater than the change in the position and posture of the painting gun,
The average moving distance of the intermediate arm portion may be determined, and the moving time between teaching points may be determined based on the magnitude of the moving distance. Additionally, the length of the arm of the robot body may also vary. The industrial robot may be another robot such as a sealing robot instead of a painting robot.

As described above, in the industrial robot of the present invention, given points in the three axial directions of the three-dimensional orthogonal coordinate system fixed to the second movable part are set as the reference point of the robot body based on the stored position data. , a first calculation means for calculating the difference between the first position and the second position in which the movable part can move next; and a second calculating means for calculating the average distance by averaging the magnitudes of the three differences. Since the second calculation means is provided, it is determined not only the moving distance of the tip position of the second moving part but also the attitude of the second moving part or the size of the moving distance of the tip of the first moving part. By determining the movement or movement time of the robot body between teaching points according to the average distance, the angular velocity of each joint of the robot body does not become too large, the control is easy, and the entire robot body is smooth. This makes it possible to avoid sudden changes in the movement of the movable parts of the robot body.

[Brief explanation of drawings]

1 is a front explanatory view of the main body of a painting robot according to a preferred embodiment of the present invention, FIG. 2 is a plan view of the robot main body of FIG. 1, and FIG. 3 is a movable part of the robot main body of FIG. 1. FIG. 4 is an explanatory diagram showing the control system of the robot body shown in FIG. 1, and FIG. 5 is an explanatory diagram showing the method of control by the control system shown in FIG. 4. 2... Robot body, 3... Base, 4a, 4b, 4
c, 4d, 4e, 4f...Joint, 5e...Wrist, 5f
...painting gun, 10...storage device, 11, 14, 1
5, 17... Arithmetic unit.

Claims (1)

[Scope of utility model registration request] A robot body including a paint gun attached to the tip of a movable part movably attached to a base via a joint, and a storage means for storing position data of the paint gun to be sequentially positioned. , if the given points in the three axial directions of the three-dimensional orthogonal coordinate system fixed to the painting gun are at the first position and the next, based on the stored position data, with respect to the reference point of the robot body. a first calculation means for calculating the difference between the painting gun and the second position where the paint gun can move; a second calculation means for calculating the average distance by averaging the magnitudes of the three differences; an industrial robot comprising: third calculation means for determining the operation time of the robot body according to the operation time of the robot body.