JPH0573118A - Robot controller - Google Patents

Abstract

PURPOSE:To consistently logically handle the operations of a robot without handling any specified operation as an exception by enlarging concept for the operations of the robot. CONSTITUTION:While considering an external coordinate system defined on the outside of a robot 40 and an indirect definition coordinate system defined indirectly to the external coordinate system, an operation at every driving axis of the robot 40 is defined as an L operation, the operation of a tool concerning the coordinate systems at the tool control point of the robot 40 is defined as a K operation, the operation of moving the tool horizontally to the external coordinate system is defined as an N operation, the operation of changing the posture of the tool axially to the external coordinate system is defined as a Q operation, the operation making the position and/or posture of the tool coincident with the position and posture of the indirect definition coordinate system is defined as an I operation, and the operation of changing the position and posture of the arm of the robot 4 without changing the position and posture of the tool is defined as an F operation. The robot 40 is controlled by providing L, K, N, Q, I and F operation processing means 11-16 respectively corresponding to the operating commands expressing the respective L, K, N, Q, I and F operations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for an industrial robot, and more particularly to a robot controller for controlling the operation of a robot having a tool, a plurality of drive shafts and an arm connecting the drive shafts.

[0002]

2. Description of the Related Art The progress of industrial robots is remarkable, but in the process of this progress, the purpose of the robots is to move first, and the movements of the robots have been improved in accordance with the expanding use. That is, when the application is changed, either one or both of a new design of the robot machine and a new operation function incorporated in the control device of the robot have been taken.

[0003] The basic motions of ordinary industrial robots are related to the so-called link motion mainly consisting of independent motions of each arm of the robot and the coordinate system of the tool attached to the tip of the robot arm. There are two types of so-called tool axis movements (sometimes called Cartesian movements), to which linear movements and circular movements are added, and these four movements are the basic movements of the robot. Linear motion and circular motion are sometimes called complementary motions. This is because the linear motion and the circular motion are given prior to the designation of the motion because the motion teaching of the conventional robot is performed by teaching and playback.
This is because the passing points are internally calculated and generated for the points or three points. The definition of the motion in these basic motions is based on that the robot has once been in its position or its posture. Further, since the position and orientation of the tool in the three-dimensional space are represented by six parameters (that is, the degree of freedom is 6), conventionally, motion control of a robot has been considered centering on a 6-axis robot. Others are treated as special robots.

[0004]

However, in the above-mentioned flow of technological improvement, the viewpoint of what kind of operation the robot is originally required to perform as a machine is lacking. However, the response from the robot becomes ad hoc on the control side of the robot, causing confusion on the side of providing the robot technology. In other words, even if the control methods are not so different in nature, they are treated as if they were completely different, or because the basic operation is only a certain range of operations, all operations outside this range are exceptional operations. There is a problem that it is treated as.

Further, it cannot be said that all the motions of the robot are covered only by the motion concept of only the link motion, the tool axis motion, the linear motion, and the arc motion. For example, an operation of matching a control point of a tool of a robot with a point outside the robot determined by an input from a vision input device (image input device) or the like is not included in the conventional operation category. This is because the robot has never approached that point in the past, and it is unknown whether or not it can reach that point. Even then, there are times when you want the robot to get as close as possible to that point.
Furthermore, when two or three points are given, it is sometimes desired that the user make a motion other than a linear motion or a circular motion. The movement of an arm for collision avoidance in a robot having joints of 7 or more axes cannot be captured by the above-described basic operation. Other than this, an operation that matches the posture of the tool with the coordinate system at a point defined on an object other than the robot is an operation that first appeared when the vision system was attached to the robot. It is not within the scope of the basic operation described above. Even in such a specific case, there is not only one combination of the coordinate system axis of the object and the coordinate system axis of the tool axis, but the operation considering such a combination is also clarified in the basic operation described above. Not defined in.

As a further big problem, although there should be no difference from the viewpoint of the control theory of the robot, the handling of the control is completely different between the 6-axis robot and the non-6-axis robot under the present circumstances. , Except 6 axes are treated as exceptions. When the number of axes is small, it should be considered that the feasible range is narrowed by the number of axes. Further, the basic operation described above is convenient for handling when teaching a robot using a teaching box, but is not always convenient when performing so-called off-line teaching using a CAD or vision input device. Is not good.

An object of the present invention is to extend the concept of robot motion to provide a robot controller capable of handling robot motion logically and consistently without exception handling of specific motions. Especially.

[0008]

In a robot controller according to the present invention, a coordinate system defined outside the robot is an external coordinate system, and a coordinate system indirectly defined with the external coordinate system is an indirect defined coordinate system. System, the motion for each drive axis is L motion, the motion of the tool with respect to the coordinate system at the control point of the tool is K motion, and the motion for translating the tool with respect to the external coordinate system is N motion. To change the posture of the robot with respect to the direction of the axis of the external coordinate system
An operation is a motion for matching the position and / or the posture of the tool with the position and the posture in the indirectly defined coordinate system is an I motion, and a motion for changing the position and the posture of the arm without changing the position and the posture of the tool. When an operation command representing the L operation is input when the F operation is performed, the operation command is analyzed to generate a control signal to each drive axis so that the robot performs the L operation. Processing means, and K operation processing means that, when an operation command representing the K operation is input, analyzes the operation command and generates a control signal to each drive axis so that the robot performs the K operation. When an operation command representing the N operation is input,
When N motion processing means for analyzing the motion command and generating a control signal to each of the drive axes so that the robot performs the N motion, and a motion command representing the Q motion are inputted, the motion command is inputted. When Q operation processing means for analyzing and generating a control signal to each of the drive axes so that the robot performs the Q operation, and an operation command representing the I operation are input, the operation command is analyzed and I for generating a control signal to each of the drive axes so that the robot performs the I operation.
An operation processing means, and an F operation processing means which, when an operation command representing the F operation is input, analyzes the operation command and generates a control signal to each drive axis so that the robot performs the F operation. Have.

[0009]

[Function] The robot performs L motion, K motion, N motion, Q motion,
An L operation processing means, a K operation processing means, an N operation processing means, a Q operation processing means, an I operation processing means and an F operation processing means which generate a control signal to perform each of the I operation and the F operation are provided for each operation. Since it is provided correspondingly, the operation that directly controls each drive axis, the operation of the tool based on the coordinate system at the control point of the tool, the operation of the tool based on the external coordinate system, the operation of the tool based on the indirectly defined coordinate system, When the same robot controller can realize the operation of moving only the arm without moving the tool, the internal operation logic of the robot controller becomes clear, and offline teaching using a vision input device or CAD is performed. Can be controlled logically and consistently.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a robot controller according to an embodiment of the present invention, FIGS.
It is a figure explaining K operation, N operation, Q operation, I operation, and F operation. The robot control device 1 includes an input device 30.
It is for controlling the robot 40 based on the operation command input from the input control means 10, L operation processing means 11, K operation processing means 12, N operation processing means 13, Q.
It comprises motion processing means 14, I motion processing means 15, F motion processing means 16, and robot control means 20. As shown in FIG. 2, the robot 40 has six axes, and the six drive shafts 41 corresponding to each degree of freedom have arms 43.
And the tool 42 is attached to the tip.

The input control means 10 receives an operation command from the input device 30, and if the operation command is an L operation command, it is sent to the L operation processing means 11, if it is a K operation command, to the K operation processing means 12, and N is sent. If it is an operation command, N operation processing means 13
The Q operation command is transferred to the Q operation processing means 14, the I operation command is transferred to the I operation processing means 15, and the F operation command is transferred to the F operation processing means 16. is there. The L motion processing means 11, the K motion processing means 12, the N motion processing means 13, the Q motion processing means 14, the I motion processing means 15, and the F motion processing means 16 respectively have an L motion command, a K motion command, and an N motion command. , Q operation command, I operation command, F operation command are analyzed, and the robot 40 uses the L
A control signal for each drive shaft 41 of the robot 40 is generated and transferred to the robot control means 20 so that each of the operation, the K operation, the N operation, the Q operation, the I operation, and the F operation is performed. The robot control means 20 includes the respective motion processing means 11 to 11.
This is for actually controlling the drive of each drive shaft 41 of the robot 40 based on the control signal from 16. For example, each drive shaft 41 is controlled by servo control.

Here, the L operation, K operation, N operation, Q operation, I operation and F operation will be described with reference to FIGS. The L motion represents the movement of each drive shaft 41. As shown in FIG. 2, each arm 43 moves by moving each drive shaft 41, and the position and posture of the tool 42 change.

The K motion represents the movement of the tool 42 with respect to the coordinate system (xyz coordinate system shown) at the control point of the tool 42, and as shown in FIG. 3, each axis in the coordinate system at this control point. Includes movements in directions and rotations around each axis. The N motion represents a movement of moving the tool in parallel with respect to an external coordinate system (XYZ coordinate system in the drawing), that is, a coordinate system defined by other than the robot. As shown in FIG. 4, the movement of bringing the tool close to the origin of the external coordinate system, It consists of moving the tool away from the origin of the external coordinate system and moving the tool in parallel in each axis of the external coordinate system.

The Q motion represents a motion that changes the attitude of the tool with respect to the direction of the axis of the external coordinate system, and is shown in FIGS.
As shown in, align the axis of the coordinate system defined by the control points of the tool with the direction of the axis of the external coordinate system, that is, make the axis direction of the coordinate system at the control point of the tool parallel to the axis direction of the external coordinate system. Consists of movements to make. FIG. 5 (a) shows a case where only the Z axis is overlapped, and FIG. 5 (b) shows a case where all three axes are overlapped.

The I motion is an indirectly defined coordinate system (X'Y 'in the figure).
Z'coordinate system), that is, a motion for matching the position and / or orientation of the tool with the position and orientation in the coordinate system indirectly defined with the external coordinate system, as shown in FIGS. 6 (a) and 6 (b). , X ′ with respect to the external coordinate system represented by XYZ coordinates
An indirect defined coordinate system represented by Y'Z 'coordinates is defined, and a motion is made to match the indirect defined coordinate system with the coordinate system at the control point of the tool 42. For example, in the conventional arc motion, if an external coordinate system is defined at the center of the arc and the coordinate system defined by points on the circumference is an indirect defined coordinate system, this I
It can be realized by operation. The I motion is used not only for the circular motion but also for defining a general complicated motion. Note that FIG. 6 (a) generally shows the I motion, and FIG. 6 (b) illustrates the conventional arc motion of the I motions.

The F movement represents a movement for changing the position and posture of the arm without changing the position and posture of the tool. As shown in FIG. 7, for example, the arm 43 in the middle portion is moved without moving the tool 42. The operation of moving from the upper [FIG. 7 (a)] to the lower [FIG. 7 (b)] is shown. This F movement realizes a collision avoidance movement in a robot having redundant axis arms. The correspondence between each of these operations and the operation of the conventional robot will be described. The L operation is completely consistent with the conventional link operation. Tool 4 is one of the traditional tool axis motions.
If the origin of the second coordinate system is on the tool 42, it is represented by K motion, and if the origin of the coordinate system of the tool 42 is slightly away from the tool 42, it is represented by N motion and Q motion. Further, the conventional linear motion is represented by N motion or a combination of N motion and Q motion. The conventional circular motion is represented by I motion. In addition to this, the I motion includes a weaving motion of a welding robot and a cooperative motion of two arms such as a double-arm robot. In the coordinated movement by the two arms, the movements of the left and right arms are two indirect coordinate systems defined indirectly from the coordinate system defined in the center of the motion requested by the object (that is, the external coordinate system). This is because it is defined according to the movement of. The center of motion referred to here means, for example, the portions of the rotary shafts of the two blades with scissors, and should be determined for convenience when mathematically modeling the motion of the object to be handled.

Next, the operation of this embodiment will be described.
The operation command from the input device 30 is first input control means 1
Enter 0. In this case, the input device 30 may be a teaching device such as a teaching box, or may be a device for performing offline teaching using a vision input device or CAD. The input control means 10 determines what kind of operation command the input operation command is, and the L operation processing means 11, the K operation processing means 12, and the N operation processing means 1
This operation command is transferred to the corresponding one of 3, Q operation processing means 14, I operation processing means 15, and F operation processing means 16.

If the motion command is the L motion command, this motion command is for driving the specific drive shaft 41 by the designated amount, and therefore the L motion processing means 11 analyzes this motion command and the motion command. Based on the above, a control signal for moving the corresponding drive shaft 41 by the designated amount is created, and the control signal is transferred to the robot control means 20. When the motion command is the K motion command, this motion command specifies the parallel movement and rotation of the tool 42 at the control point of the tool 42, so the K motion processing means 12 determines the parallel movement amount and rotation. The amount is converted into the drive amount of each drive shaft 41, a control signal for driving and controlling each drive shaft 41 is created based on the converted drive amount, and this control signal is transferred to the robot control means 20.

When the motion command is the N motion command, the motion command designates the parallel movement of the tool 42 with respect to the external coordinate system. Therefore, the N motion processing means 13 causes the coordinate system at the control point of the tool 42 to operate. And the external coordinate system are obtained, the parallel movement amount of the tool 42 represented by the coordinate system at the control point of the tool 42 is obtained based on this positional relation, and this parallel movement amount is set as the drive amount of each drive shaft 41. Converted,
A control signal for driving and controlling each drive shaft 41 is created based on the converted drive amount, and this control signal is transferred to the robot control means 20.

When the operation command is the Q operation command, this operation command specifies the rotation of the tool 42 with respect to the external coordinate system. Therefore, the Q operation processing means 14 causes the tool 4 to rotate.
The attitude relationship between the coordinate system at the second control point and the external coordinate system is obtained, and the rotation amount of the tool 42 represented by the coordinate system at the control point of the tool 42 is obtained based on this attitude relationship. The control signal is converted into the drive amount of 41, and a control signal for driving and controlling each drive shaft 41 is created based on the converted drive amount, and this control signal is transferred to the robot control means 20.

When the motion command is the I motion command, this motion command attempts to make the coordinate system of the control point of the tool 42 coincide with the indirect defined coordinate system. The positional relationship between the indirectly defined coordinate system and the coordinate system at the control point of the tool is calculated from the external coordinate system based on the specified motion, and the tool is based on the latter positional relationship. The parallel movement amount and the rotation amount of 42 are calculated, the calculated parallel movement amount and the rotation amount are converted into the drive amount of each drive shaft 41, and each drive shaft 41 is drive-controlled based on the converted drive amount. A control signal is created and this control signal is transferred to the robot control means 20.

When the motion command is the F motion command, this motion command specifies the movement of the arm 43 under the constraint condition that the tool 42 is fixed. Therefore, the F motion processing means 16 operates under this constraint condition. The possible movements of the arm 43 are calculated, and each drive shaft 41 that causes the arm 43 to make this movement is calculated.
The drive amount is calculated, a control signal for driving and controlling each drive shaft 41 is created based on the calculated drive amount, and this control signal is transferred to the robot control means 20.

When the control signals are transferred from the motion processing means 11 to 16, the robot control means 20 drives and controls each drive shaft 41 based on the transferred control signals so that the robot 40 is actually moved. To do. As described above, L operation, K operation, N operation, Q operation, I operation and F operation
The robot controller 1 of the present embodiment outputs motion commands that represent motions.
By inputting to the robot 40, the robot 40 can perform a given motion.

Although the embodiment of the present invention has been described above, comparing the robot controller of the present invention with the conventional robot controller, the robot controller of the present invention is
The robot motion concept is categorized by the motions, K motions, N motions, Q motions, I motions, and F motions, and the internal design is made based on that, whereas the conventional robot control device uses the above-mentioned classifications. By the way, usually L motion and K
It mainly deals with motions, and even a so-called high-end machine only incorporates a part of N motion, Q motion or I motion. And, in the conventional robot control device, the concept of operation of the robot is not grasped based on the classification as described above, and therefore, the internal structure is not logically designed, and the robot is logically understood. It becomes difficult for the operator to learn the movement of the robot, and there is a situation in which the operator and the robot "fight" each other. On the other hand, the robot control device of the present invention is capable of sufficiently supporting not only the teaching by the teaching box but also various off-line teachings, because the actions are categorized in the orderly manner as described above. And 6
Robots with the number of axes other than the axes can be handled in the same manner as in the case of 6 axes.

[0025]

As described above, according to the present invention, the L motion processing means K for generating a control signal so that the robot performs each of L motion, K motion, N motion, Q motion, I motion and F motion, K. By providing the motion processing means, the N motion processing means, the Q motion processing means, the I motion processing means and the F motion processing means corresponding to each motion, the motion of directly controlling each drive axis, the coordinate system at the control point of the tool Based on the same robot controller, the movement of the tool based on the external coordinate system, the movement of the tool based on the external coordinate system, the movement of the tool based on the indirectly defined coordinate system, and the movement of only the arm without moving the tool can be realized.
The internal operation logic of the robot controller is clarified, and even when performing offline teaching using a vision input device or CAD, logically consistent control can be performed, and the number of axes other than 6 This robot has the effect that it can be handled in the same manner as in the case of 6 axes.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a robot controller according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an L operation of the robot.

FIG. 3 is a diagram illustrating a K operation of the robot.

FIG. 4 is a diagram illustrating N motion of the robot.

5 (a) and 5 (b) are diagrams for explaining the Q operation of the robot.

6 (a) and 6 (b) are diagrams for explaining the I motion of the robot.

7 (a) and 7 (b) are diagrams for explaining the F motion of the robot.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 robot control device 10 input control means 11 L motion processing means 12 K motion processing means 13 N motion processing means 14 Q motion processing means 15 I motion processing means 16 F motion processing means 20 robot control means 30 input device 40 robot 41 drive axis 42 tool 43 arm

Claims (1)

[Claims] 1. A robot controller for controlling the operation of a robot having a tool, a plurality of drive axes, and an arm connecting the drive axes, wherein a coordinate system defined outside the robot is an external coordinate system. A coordinate system indirectly defined with an external coordinate system is defined as an indirect defined coordinate system, and the movement of each drive axis is defined as L motion.
The motion of the tool with respect to the coordinate system at the control point of the tool is K motion, the motion of translating the tool with respect to the external coordinate system is N motion, and the attitude of the tool is with respect to the direction of the axis of the external coordinate system. Q to change movement
An operation is a motion that matches the position and / or the posture of the tool with the position and the posture in the indirectly defined coordinate system is the I motion, and the position and the posture of the arm are changed without changing the position and the posture of the tool. When a motion is an F motion and an motion command representing the L motion is input, the motion command is analyzed to generate a control signal to each drive axis so that the robot performs the L motion. Motion processing means, and K motion processing means that, when a motion command representing the K motion is input, analyzes the motion command and generates a control signal to each drive axis so that the robot performs the K motion. An N motion processing unit that analyzes a motion command when the motion command representing the N motion is input, and generates a control signal to each of the drive axes so that the robot performs the N motion. When an operation command representing the Q operation is input, the operation command is analyzed to generate a control signal to the drive axes so that the robot performs the Q operation. When an operation command representing the operation is input, I operation processing means for analyzing the operation command and generating a control signal to each of the drive axes so that the robot performs the I operation, and the operation command representing the F operation. A robot controller comprising: an F motion processing unit that, when input, analyzes the motion command and generates a control signal to each of the drive axes so that the robot performs the F motion.