JPH07104710B2 - Motion control device for articulated robot - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a simple motion control method and device for an articulated robot.

[Background of the Invention]

Most of the conventional industrial robots are operated by a teaching play back. Such an industrial robot has a coordinate system inside the control device for describing its own operation. In the case of the orthogonal robot, it can be considered that this internal coordinate always coincides with the stationary coordinate system that we humans recognize, so the operation of the orthogonal robot is relatively easy. On the other hand, in the case of an articulated robot, it is difficult to operate on the basis of a stationary coordinate system because of its articulated structure, and in an ordinary articulated robot,
Based on the internal coordinate system that is adjusted with sufficient accuracy to match the stationary coordinate system, it has a control function to move the tip of the hand straight and to rotate the wrist axis. When teaching the operation of the robot, a method is used in which the robot is actually operated up to the working point by using this function to teach the position and posture at the working point. (JP-A-51-
However, with such a method, it is not possible to know the exact axial direction of the coordinate system in the robot internal coordinates, so it is necessary to precisely orient the robot in a certain direction, or the wrist axial direction must be precise. There was a problem that it was difficult to meet the requirements when it was necessary to turn it horizontally.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for easily realizing precise position and attitude control of an articulated robot, which is difficult to perform by a conventional manual method.

[Outline of Invention]

In order to achieve the above-mentioned object, the present invention controls the motion of an articulated robot, and presents a current state storage means for storing the current motion joint angle of each motion axis, the hand position, and the posture, and the multi-joint robot. The posture of the articulated robot is designated by the posture pattern storage means for storing a particular posture pattern of the shape-robot, the posture pattern designated by the operation of this operating means, and the current posture of the robot in the current-state storage means. And an attitude pattern control means for generating an operation signal of the articulated robot that matches the generated attitude pattern and outputting the operation signal to a drive control means for driving and controlling each operation axis of the articulated robot. is there.

Example of Invention

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an articulated robot equipped with an example of the device of the present invention. Reference numeral 2 is an articulated robot that is driven by the motion control device 1 for the robot.

This articulated robot is composed of a base 3, a swivel 4, a first arm 5, a second arm 6 and wrist axes 7 and 8. A gripper 9 for handling a work is provided at the tips of the wrist shafts 7, 8.

The operation of this robot is: rotation of the swivel base 4 about the axis S1 with respect to the base 3, rotation of the first arm 5 about the axis S2 with respect to the swivel 4, rotation of the second arm 6 about the axis S3 with respect to the first arm 5, It is obtained by appropriately combining the rotation of the wrist shaft 7 about the axis S4 with respect to the second arm 6, the rotation of the wrist shaft 8 about the axis S5 with respect to the wrist shaft 7, and the opening / closing of the gripper 9.

The operation control device 1 is an operation control means for applying various operation signals to the robot, and an operation control means for receiving a signal from the operation means 10 and a means for executing an operation required by the robot, the operation control means comprising a key switch or the like. 11, a current state storage means 15 for storing the motion joint angles, hand positions, and attitudes of the respective current motion axes of the robot, attitude pattern storage means 19, and attitude pattern control means 18 activated by the operation control means 11.
Manual control means 12, teaching control means 13 and playback control means 14, input means 20, input control means 21, display means 22, display control means 23, and drive control of each joint of the robot are actually performed. It is composed of a drive control means 17.

Next, the operation of the operation control device 1 of the present invention will be described. For convenience of explanation, each operation unit of the operation control device 1 is configured to be activated by a timer incorporated in the operation control device (not shown) at a constant sampling time, for example, every 20 msec to execute a predetermined operation. ing.

First, a power-on operation control device 1 (not shown)
The initialization operation of will be described. When the power is turned on,
The operation control device 1 causes the articulated robot to perform the origin alignment operation by operating the operation means 10. By this origin alignment operation, the mechanical origin and the electrical origin of the articulated robot are synchronized, and the robot takes a fixed mechanically determined posture. As a result, internal coordinate points for motion control of the articulated robot are established inside the motion control device, and the current motion storage unit 15 stores the current motion joint angle, hand position, and posture condition. It also gives the actual joint angle of the articulated robot. For example, the rotation angle of the incremental encoder for measuring the rotation angle of the servo motor that drives the joint portion and the movement joint angle of the robot inside the movement control device can be synchronized. As a result, the articulated robot can be controlled to an arbitrary movement via the drive control means 17 by the signal for controlling the motion joint angle stored in the internal coordinate system. When this origin alignment operation is completed,
Next, the articulated robot is manually operated to teach the work to be actually performed. At this time, there arises a case where it is necessary to cause the articulated robot, which is the object of the present invention, to assume a specific and accurate posture state.

The method will be described below. First, FIG. 2 shows the definition of the operating angle of the articulated robot of FIG. Of Figure 2
S1, S2, ..., S5 respectively correspond to the operation axes in FIG. 1, and here the operation angles are shown. With this definition, the posture pattern of the articulated robot stored in the posture pattern storage means 19 can be defined by various methods. For example, if the following pattern (S1, S2, S3, S4, S5) is set to be stored in (1), this means that the movement angle of the articulated robot itself is set as the posture pattern. . When the following patterns (S2, S2 + S3, S2 + S3 + S4) are set to be stored in (2), the postures of the first arm 5, the second arm 6, and the wrist 7 of the articulated robot with respect to the horizontal plane, respectively. An angle, that is, an absolute posture pattern in a stationary coordinate system will be defined. Here, in the case of (2) above, the value is (45 °, 0 °, −90 °) (3) That is, the first arm is 45 ° with respect to the horizontal plane, and the second arm is with respect to the horizontal plane. The operation of the present invention will be described with reference to FIG. 1 assuming that the wrist bending axis S4 is 0 ° and is stored in the posture pattern storage means 19 in a vertically downward pattern.

First, it is assumed that the operation means 10 is operated to specify the operation of the wrist bending axis S4. The operation control means 11 decodes the operation content of the operation means 10, activates the posture pattern control means 18, and instructs the operation of the wrist bending axis S4. Posture pattern control means 18
Calculates the value of (S2 + S3 + S4) by taking out the present values of S2, S3, S4 from the present state storage means 15 and obtaining the difference Δ from the value −90 ° retrieved from the posture pattern storage means 19.

Δ = (− 90) − (S2 + S3 + S4) (4) Next, a predetermined small angle δ is compared with Δ so that the articulated robot does not move suddenly. If δ <| Δ
In case of |, S4 + sgn (Δ) · δ is updated to the new operating angle of S4. In the case of δ | Δ |, S4 + Δ is updated to the new operating angle of S4.

In this way, the motion angle of the current state storage means 15 is updated, and then the new motion joint angle S1 is calculated from the relational expression defined by the mechanism of the articulated robot established between the motion angle and the hand position and posture. , S2, ..., S5, a new hand position / posture is obtained, and the hand position / posture data of the current state storage means 15 is updated. Finally, the operating angle of the current state storage means 15 is converted into a drive signal of an actuator for driving the joint shaft of the articulated robot and output to the drive control means 17. The drive control means 17 operates the robot according to the drive signal.
Here, as will be understood from the above, the posture pattern control means 18 only generates the drive signal for operating the motion joint angle of the robot by a small amount in one operation. Therefore, in order to match the posture of the designated joint portion of the multi-joint robot with the value stored in the posture pattern storage means 19, the above-described operation of the posture pattern control means 18 must be repeated many times.

As a method of repeating a large number of times, when the posture pattern control means 18 is activated by the operation of the operating means 10, the posture pattern control means 18 automatically executes a large number of repetitions, and when the designated posture is obtained, the posture pattern control is performed. Even when the operation of the means 18 is completed and the operation of the next operation means 10 is awaited, as long as the operation of the posture pattern control means 18 is completed in one operation and the operation of the operation means 10 is continued. Alternatively, the operation may be repeated many times. In the latter case, when the operation of the operation means 10 is aborted, the motion control is aborted even if the posture of the articulated robot does not match the designated posture pattern. In this case, the operating means
Of course, when the operation of 10 is restarted, the operation control is continued.

Next, for example, when a command is issued to operate the operating means 10 to control the operating angle S2 of the first arm, the operating angle S2 of the first arm is raised by 45 ° from the horizontal plane by the same procedure as described above. Controlled by.

Here, the operation of the operating means 10 has been described as a method of matching each of the operating angles of the articulated robot with the designated posture pattern. Alternatively, the articulated robot may be operated so that the attitude of the articulated robot matches all the attitude patterns. Alternatively, a plurality of posture patterns as described above may be prepared and one of the posture patterns may be selectively controlled.

In the above description, when the robot motion angle is controlled, the new position and orientation are calculated from the new motion angle, and the current state is updated.However, the robot wrist motion angle, in this case, When (S4, S5) is controlled, the position of the current state is unchanged, that is, the motion joint angle (S1, S5) that satisfies the current position and the new posture (S4, S5) is satisfied.
2, S3) is calculated, and (S1, S
2, S3) may be updated. In this case, the hand position of the robot is kept unchanged while the wrist motion angle is matched with the target posture pattern.

Next, in the above description, the posture pattern stored in the posture pattern storage unit 19 is described as a constant value, but the input unit 29 forms an update command as necessary,
By the action of the input control means 21, the posture pattern storage means 19
The effect of the present invention is further enhanced by making it possible to update the memory pattern. Here, as the input means 20, a numeric input device such as a numeric keypad, a keyboard input device, or a voice input device can be used. When the input means 20 is operated and the display control means 23 is operated via the input control means 21 to cause the display means 22 to display the posture pattern stored in the posture pattern storage means 19, the storage pattern It becomes easier to confirm and update and the effect of the present invention becomes greater. Here, the display means 22 may be a liquid crystal character display device, a liquid crystal graphic display device, a CRT display, a graphic display, or a 7-segment display device.

As described above, according to the present invention, the operation means 10 is provided, the operation axis of the articulated robot is specified, and the attitude pattern control means is activated to change the attitude of the specified operation axis. It is possible to accurately and easily match the corresponding posture stored in the pattern storage means 19. Therefore, the operation means 10 is operated, the manual control means 12 is started via the operation control means 11, and the operation of the manual control means 12 for manually operating the articulated robot and teaching the articulation to the articulated robot. It will be understood that, when the present invention is carried out in combination, the operation of the present invention makes it very easy to teach the operation of the articulated robot. By the way, the position and posture of the operating point of the articulated robot obtained by the action of the posture pattern control means 18 and the manual control means 12 are stored in the current state storage means 15, and this is stored by the operation means 10. By the operation of the teaching control means 13 via the operation control means 11, the teaching state storage means 16 sequentially stores. In this way, when the operation teaching of the articulated robot is completed, the operation of the operation means 10 activates the play back control means 14 via the operation control means 11, and the means 14 is stored in the teaching state storage means 16. The articulated robot is operated while interpolating the position and posture state of the articulated robot according to certain rules, that is, the taught work is executed by the articulated robot.

〔The invention's effect〕

As described above, according to the present invention, the articulated robot can be simply and accurately controlled in a desired movement direction and posture simply by operating the operation switch, so that the labor required for teaching the movement of the robot is significantly increased. It is possible to reduce the number of movements, and it is possible to teach accurate movements.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a motion control device for an articulated robot according to the present invention, and FIG. 2 is a diagram for explaining the definition of a motion joint angle of the robot. DESCRIPTION OF SYMBOLS 1 ... Robot operation control device, 2 ... Robot, 10 ... Operating means, 11 ... Operation control means, 15 ... Present state storage means, 18 ...
Attitude pattern control means, 19 ... Attitude pattern storage means, 20
... input means, 22 ... display means.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B25J 13/06 G05B 19/18 (72) Inventor Masayasu Akaiwa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd., Production Engineering Laboratory (72) Inventor, Mitsuo Sato, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture, Ltd. Production Engineering Laboratory, Hitachi, Ltd. (72) Inventor, Kyozo Tachibana, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture No. 292 Co., Ltd. Production Engineering Laboratory, Hitachi, Ltd. (56) Reference JP-A-59-27306 (JP, A) JP-A-59-76793 (JP, A)

Claims (15)

[Claims] 1. An arm connected by at least one or more motion axes rotating about a horizontal axis, a current state storage means for storing a current motion joint angle of the motion axis, a hand position and a posture, and the motion. In a multi-joint robot including drive control means for driving and controlling an axis, a posture pattern storage means that stores in advance a posture of the robot as a motion joint angle from an axis set orthogonal to a motion axis, and the posture. An operating means for designating the operating joint angle of the operating axis stored in the pattern storing means, and an operating joint angle stored in the posture pattern storing means selected in response to the instruction from the operating means based on the instruction from the operating means. And the current motion joint angle stored in the current state storage means, and the current motion joint angle is designated and selected in the posture pattern storage means. Obtains a signal operation joint angles to match the time, the operation control device of the articulated robot, characterized in that a posture pattern control means outputs the signal to the drive control means. 2. The posture pattern control means operates at every minute sampling time, and the movement amount of the movement joint angle of the multi-joint robot per sampling time is less than a predetermined minute amount. An operation control device for an articulated robot according to claim 1. 3. The posture pattern control means, when activated by the operation of the operating means, continues the movement until the posture of the articulated robot matches the movement joint angle of the designated posture pattern. An operation control device for an articulated robot according to claim 1. 4. The posture pattern control means is started by the operation of the operating means, and the operation of the operating means is canceled even if the posture of the articulated robot does not match the operating joint angle of the designated posture pattern. The motion control device for an articulated robot according to claim 1, wherein the motion is stopped. 5. An operation control of an articulated robot according to any one of claims 2 to 4, characterized in that input means for updating the contents of the posture pattern storage means is provided. apparatus. 6. The motion control device for an articulated robot according to claim 5, wherein the input means is a ten-key input device for inputting a motion joint angle. 7. The motion control device for an articulated robot according to claim 5, wherein the input means is a keyboard input device for inputting a motion joint angle. 8. The motion control device for an articulated robot according to claim 5, wherein the input means is a voice input device for inputting a motion joint angle. 9. The multi-joint type according to claim 6, further comprising display means for displaying the content of the motion joint angle of the posture pattern storage means. Robot motion control device. 10. The display means for displaying the content of the motion joint angle of the posture pattern storage means is provided with an input means for giving a motion instruction.
An operation control device for an articulated robot according to the item. 11. An operation control device for an articulated robot according to claim 9, wherein the display means is a liquid crystal character display device. 12. The display means is a liquid crystal graphic display device according to claim 9 or 10.
10. An operation control device for an articulated robot according to item 10. 13. The operation control device for an articulated robot according to claim 9 or 10, wherein the display means is a CRT display. 14. The display means according to claim 9, wherein the display means is a graphic display.
10. An operation control device for an articulated robot according to item 10. 15. The motion control device for an articulated robot according to claim 9 or 10, wherein the display means is a 7-segment display device.