JPH1158275A - Control device for articulated robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize precise motion by shortening a command cycle of an articulated robot. SOLUTION: This control device is furnished with a joint driving means 23 for each joint, a serial data line 3 to connect the joint driving means 23 to each other and a control means 22 to deliver a joint control signal to the serial data line 3. The joint control signal has the joint number for setting of joint groups to specify a plural number of the joints as one set of the joint group and a joint control data in the joint group arranging this joint number only in the setting order of the joints. A data selection means 25 to select the control data of the corresponding joints from a control data for the joints in the joint control signal is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an articulated robot which controls each joint by transmitting a control signal to a signal line connecting each joint of the articulated robot.

[0002]

2. Description of the Related Art A conventional control device of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 2-273806. In the articulated robot disclosed in this publication, joint driving means for controlling a servo motor of each joint is provided for each joint, and these joint driving means are connected to each other by a serial data line, and control is performed on this serial data line. The means is configured to transmit a joint control signal. The joint control signal has a fixed-length communication data format including control data of all joints.

A control device of this conventional articulated robot will be described with reference to FIGS. FIG. 8 is a block diagram showing a conventional control device for an articulated robot, FIG. 9 is a block diagram of a joint driving unit, and FIG. 10 is a diagram for explaining the operation of the joint driving unit. In these figures, reference numeral 1 denotes control means, 2 denotes joint driving means for each joint, and 3 denotes a serial data line. The control means 1 and each joint driving means 2-1 to 2-
n are connected. Reference numeral 2-1 denotes a joint driving unit of the first joint, and 2-n denotes a joint driving unit of the nth joint.

As shown in FIG. 9, each of the joint driving means 2-1 to 2-n includes a fixed-length communication data converter 4 for reading a command and control data of a corresponding joint from the serial data line 3. A drive arithmetic processor 5 for performing control arithmetic processing for joint drive from the command and the control data and transmitting a drive command, and a joint drive circuit 7 for driving a joint actuator 6 such as a servomotor based on the drive command. And

[0005] The control means 1 has a serial data line 3
As shown by reference numeral 8 in FIG. 10, the joint control signal to be transmitted to the controller comprises a command which is a command for the joint and control data of all the joints. In order for the fixed-length communication data converter 4 to read out a command and control data of a corresponding joint (hereinafter, this joint is simply referred to as “self-joint”) from the joint control signal 8, the fixed-length communication data converter 4 uses a fixed reference numeral 9 in FIG. You are using a long filter. The filter 9 has a configuration in which a command included in the joint control signal 8 and control data of the corresponding joint are transmitted. FIG. 10 shows a state in which the fixed-length communication data converter 4 of the K-th joint reads the command 10 and the control data 11 of the own joint.

Next, the operation of the control device for a conventional articulated robot configured as described above will be described. The joint control signal 8 sent out by the control means 1 corresponds to each of the joint driving means 2-1 to 2-n
At the same time via the serial data line 3.
Each of the joint driving means 2-1 to 2-n outputs the joint control signal 8
Each of the own joints is driven based on. At this time, when the joint control signal 8 is input to each of the joint drive means 2-1 to 2-n, first, the fixed length communication data converter 4 uses the fixed length filter 9 to convert the command 10 And the control data 11 at the own joint. Next, the drive arithmetic processor 5 performs control arithmetic processing for driving the joint based on the command 10 and the control data 11, and outputs a drive command to the joint drive circuit 7. Then, the joint drive circuit 7 drives the actuator 6 based on the drive command.

[0007]

However, in the conventional articulated robot controller configured as described above, there is a limit in increasing the operating speed of the articulated robot.
This is because the joint control signal 8 employs a fixed-length communication data format. That is, since the control data of all the joints must be set in the joint control signal 8, the joint control signal 8 becomes long and the cycle of sending the command cannot be shortened.

Therefore, even when a plurality of joint groups, each of which is a set of a plurality of joints, are operated by the same control data, or when only one or a plurality of specific joints are operated, it is necessary to complete the operation by the end of the command. It takes a long time,
The operation of the articulated robot becomes slow.

The present invention has been made to solve such a problem, and an object of the present invention is to shorten a command cycle of an articulated robot so as to realize a precise operation.

[0010]

A control device for an articulated robot according to the present invention comprises a joint driving means for each joint, a signal line connecting the joint driving means in series, and a joint control signal transmitted to the signal line. Control means for transmitting the joint control signal, the joint control signal comprises: a number of joints for setting a plurality of joints in the order of a predetermined joint number as a set of joint groups; Control data of the joints in the group of joints arranged in the order of the numbers, wherein the joint drive means is provided with data selection means for selecting the control data of the corresponding joint from the joint control data in the joint control signal It is.

According to the present invention, the number of control data for each joint in the joint control signal may be the same as the number of joints in one joint group. A variable-length communication data format whose length changes according to the number of joints can be used. Therefore, the number of control data to be sent at one time can be reduced, and the command cycle can be shortened, as compared with the conventional control in which control data for all joints is sent at once.

The control device for an articulated robot according to another aspect of the present invention is the control device for an articulated robot according to the above-described invention, wherein the data selecting means includes a serial number assigned to all the joints in the order of installation. Has a calculating means for dividing the numerical value of the above by the number of joints for setting the joint group, and the control data of this joint position is selected as a joint position in the joint group using the remainder of the division performed by the calculating means. is there.

According to the present invention, the corresponding control data in the joint control signal can be selected by the calculation based on the number of joints in one joint group and the installation position of the joint.
Even if the length of the communication data format changes, the control data of the own joint can be accurately selected.

The control device for an articulated robot according to another aspect of the present invention is the control device for an articulated robot according to the invention described above, wherein the joint control signal includes a symbol indicating whether or not control is performed for all the joint groups. It has joint group designation data arranged in the order of installation, and the data selection means detects presence / absence of control of the corresponding joint group from the joint group designation data using the quotient of the division performed by the arithmetic means as the position of the joint group. It is configured.

According to the present invention, a group of joints to be controlled can be designated while employing a variable length communication data format.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, an embodiment of a control device for an articulated robot according to the present invention will be described in detail with reference to FIGS. Here, a description will be given of a control in which a plurality of joints is a set of joint groups and the plurality of joint groups perform the same operation.

FIG. 1 is a block diagram showing the structure of the joint driving means used in the control device for an articulated robot according to the present invention, FIG. 2 is a diagram for explaining the operation of the data selecting means, and FIG. It is a figure for explaining operation. In these drawings, the same or equivalent members as those described in FIGS. 8 to 10 are denoted by the same reference numerals, and detailed description is omitted.

In these figures, reference numeral 21 indicates a control device for an articulated robot according to this embodiment. The control device 21 includes a control unit 22 for transmitting a joint control signal described later, a joint driving unit 23 provided for each joint, and a serial data line 3 connecting these. In FIG. 1, the joint driving means provided at the first joint is denoted by reference numeral 23-1, and the joint driving means provided at the n-th joint is denoted by reference numeral 23-n.

The control means 22 sends out a joint control signal indicated by reference numeral 24 in FIG. The joint control signal 24 includes a command that is a command for a joint, the number L of joints for setting a plurality of joints as a set of joints, and a joint control in which the number L of joints is arranged in the order of installation of the joints. And data. The number of control data in the joint control signal 24 is the same as the number L of joints in one joint group.
Is a variable-length communication data format whose length changes according to the number L of joints.

The joint driving means 23 includes a data selecting means 25 for selecting control data of the own joint from a plurality of joint control data in the joint control signal 24, a driving arithmetic processor 5, the joint driving circuit 7, And an actuator 6. In order for the data selection means 25 to select control data, a variable length filter indicated by reference numeral 26 in FIG. 2 is used. The variable length filter 26 has a configuration in which the command 10 included in the joint control signal 24 and the control data 27 of the own joint are transmitted. FIG. 2 shows a state where the data selection means 25 of the Kth joint reads out the command 10 and selects the control data 27 (control data for the Mth joint) of the own joint. Note that the variable length filter 26 is realized by a calculation by a calculation unit 28 described later provided in the data selection unit 25.

The data selecting means 25 includes the variable length filter 2
When selecting control data using the command 6, the command 10 is first read from the joint control signal 24, and the number L of joints per joint group is read. Then, the calculation means 28 executes the calculation of the following equation (1), and obtains the transmission joint position M in the variable length filter 26 based on this calculation. M = f (K, L) ‥‥ (1) where f (x, y) is a function for calculating the remainder of division x / y of integers x and y.

That is, the numerical value of the number K of the corresponding joint among the serial numbers 1 to n assigned to all the joints in the order of installation is divided by the number L of joints for setting the joint group, and the remainder is defined as the transparent joint position M. . As a result, the variable length filter 26
M-th control data 2 out of control data for L joints
7 is transmitted.

The operation of the data selection means 25 is shown in FIG.
This will be specifically described with reference to (a) to (c). In FIG.
Divide the robot with 12 joints into 4 joints each from the top, 3
A set of joint groups is formed, and each joint group is made to perform the same operation, so that a wavy motion can be created. That is, an example is shown in which the present invention is applied to a traveling robot capable of moving forward and backward.

The command JMOV in the joint control signals 24-1 to 24-3 in FIG. 3 is a position movement command for each joint, the next numeral 4 is the number of joints in the joint group, and the four control data are It is an angle (unit: deg). When the joint control signal 24-1 shown in FIG. 3A is input to the data selecting means 25 for each joint, the posture of the articulated robot is indicated by reference numeral 29 in FIG. For example, the seventh joint (second
When the data selecting means 25 of the third joint in the group of joints) selects the control data of its own joint from the joint control signal 24-1, first, 7 is substituted into K of the equation (1). At the same time, 4 is substituted for L, and the remainder of the division, that is, 3 which is the remainder of 7/4 is obtained. This remainder 3 indicates a joint position in the joint group.

After performing the calculation in this manner, the data selecting means 25 selects the third control data (45 deg) from the four control data in the joint control signal 24-1 and outputs the third control data (45 deg). The control data and the command in the joint control signal 24-1. The drive arithmetic processor 5 performs arithmetic processing for joint drive based on the command and the control data, and outputs a drive command to the joint drive circuit 7. The joint drive circuit 7 drives the actuator 6 based on this drive command. As a result, the seventh joint rotates by 45 deg.

As described above, the data selecting means 25 of each joint selects control data from the joint control signal 24-1 so that the first joint (first, fifth, and fifth) of each of the three joint groups is obtained. The ninth joint rotates at the angle of the first control data (−45 deg), and the second joint (second, sixth and tenth joints) rotates at the angle of the second control data (45 deg). Rotate. The third joint (the third, seventh, and eleventh joint) rotates at the angle of the third control data (45 deg), and the fourth joint (the fourth, eighth, and twelfth joint).
Rotates at an angle of the fourth control data (−45 deg).

As shown in FIG. 3B, the joint control signal 24
-2, the posture of the articulated robot changes as indicated by reference numeral 30, and the joint control signal 24-3 is transmitted as shown in FIG. The posture changes as indicated by reference numeral 31.

Therefore, according to the control device for an articulated robot shown in this embodiment, the number of control data for each joint in the joint control signal 24 is the same as the number L of joints in one joint group. Since the number may be a number, the joint control signal 24 can be in a variable-length communication data format whose length changes according to the number L of joints in the joint group. Therefore, the number of control data to be sent at one time can be reduced, and the command cycle can be shortened, as compared with the conventional control in which control data for all joints is sent at once.

Further, since the corresponding control data in the joint control signal 24 can be selected by the calculation executed by the calculating means 28 provided in the data selecting means 25, even if the length of the communication data format changes, it can be accurately determined. The control data of the own joint can be selected.

The control device shown in this embodiment is suitable for a case where a plurality of joints are set as a set of joints and the plurality of joints are controlled so as to perform the same operation. This can be implemented with a joint control signal in a short communication data format corresponding to the number of joints in the group.

Second Embodiment An embodiment of a control device for an articulated robot capable of controlling only one or a plurality of joints specified by data selection means will be described in detail with reference to FIGS. FIGS. 4 and 5 show another embodiment of the data selection means.
FIG. 4 shows a case where the operation is permitted, and FIG. 5 shows a case where the operation is not permitted. FIG. 6 is a diagram for explaining the operation of the articulated robot, and FIG. 7 is a diagram showing an example in which the number of joints per joint group is changed. In these drawings, the same or equivalent members as those described in FIGS. 1 to 3 and FIGS. 8 to 10 are denoted by the same reference numerals, and detailed description is omitted.

As shown by reference numeral 41 in FIGS. 4 and 5, a joint control signal used in this embodiment defines a command which is a command for a joint and a plurality of joints as a set of joint groups. It is composed of the number of joints L for setting the joint group, the data G for specifying the joint group, and the control data for the joints arranged in the order of the joints by the number of the joints L. In this embodiment, the joint group designation data G is configured by arranging symbols indicating the presence / absence of control (operation permission / non-permission) in all the joint groups in the order of installation of the joint groups.

In order for the data selecting means 25 of each joint to select control data from the joint control signal 41, a variable length filter indicated by reference numeral 42 in FIGS. 4 and 5 is used. This variable length filter 42 is
Command 10 included in the joint control signal 41 only when the operation of the joint group including the joint having
The configuration is such that the control data 27 of the own joint is transparent. The joint operates when the data selection means 25 selects these data. FIG. 4 shows a state where the data selection means 25 of the Kth joint reads out the command 10 and selects the control data 27 (control data for the Mth joint) of the own joint. Note that the variable-length filter 42 is realized by a calculation by the calculation unit 28 provided in the data selection unit 25.

When selecting the control data using the variable length filter 42, the data selecting means 25 in this embodiment first reads the command 10 from the joint control signal 41 and sets one joint. Number of joints per group L
Is read. Then, the calculating means 28 executes the calculation of the expression (1), and obtains the transmission joint position M in the variable length filter 42 based on the calculation.

Further, according to the following equation (2),
A joint group number J for determining non-motion is obtained. J = g (K, L) ‥‥ (2) where g (x, y) is a function for calculating a quotient of division x / y of integers x and y. That is, among the serial numbers 1 to n assigned to all the joints, the numerical value of the corresponding joint number K is divided by the number L of joints for setting the joint group, and the quotient is set as the joint group number J.

Next, the data selecting means 25 reads out the joint group designation data G from the joint control signal 41 and determines whether or not the joint group number J is included in the joint group designation data G. If the joint group number J is included in the joint group designation data G, the joint is permitted to operate. If the joint group number J is not included in the joint group designation data G, the joint is designated. The joint is not allowed to move. FIG. 4 shows an example in which operation is permitted, and FIG. 5 shows an example in which operation is not permitted.

When the operation is permitted, the filter structure including the filter length of the variable length filter 42 based on the number L of joints and the position M of the transparent joint is used as in the case of the first embodiment. Is determined and changed. In other words, the filter structure has control data for L joints and transmits M-th joint data. Thus, the variable length filter 42
By using, it is possible to read out only the control data corresponding to the own joint from the control data including a plurality of joints as a set. The variable length filter 42 reads the command 10 from the joint control signal 24 in the variable length communication data format, and controls the joint data 27 of the own joint.
Is selected and sent to the drive arithmetic processor 5.

On the other hand, if the operation is not permitted,
As shown in FIG. 5, the variable length filter 42 is determined and changed to a structure that does not transmit any command and control data. As a result, the control command to the joint whose operation is not permitted is blocked from being transmitted by the data selection means 25, and the drive operation processor 5
Is not transmitted to

Data selecting means 25 according to this embodiment
6 will be specifically described with reference to FIGS. Also in this example, the robot having 12 joints is divided into four joints each from the top to form three sets of four joints. The command JMOV is a position movement command for each joint, and the control data is an angle (unit: deg). Further, a method of designating joint group operation permission and operation non-permission with the joint group designation data G is as follows: 1 is specified when operation is permitted, and 0 is specified when operation is not permitted. From the joint group to the third joint group. For example, the joint group designation data G is “010”
In the case of, the second joint group is permitted to operate and the first and third joint groups are not permitted to operate.

By transmitting the joint control signal indicated by reference numeral 41-1 in FIG. 6A, the posture of the articulated robot is indicated by reference numeral 43 in FIG. At this time, the joint group designation data G in the joint control signal 41-1 is "10
0 ”, the first joint group is permitted to operate,
Only the first to fourth joints operate based on the control data. When the joint control signal indicated by reference numeral 41-2 in FIG. 6B is transmitted, the operation of the second and third joint groups is permitted, so that each joint in the first joint group is Without operating, the joints of the other joint groups operate based on the control data, and assume the posture indicated by reference numeral 44.

As shown in FIG. 6C, the joint control signal 41
When -3 is transmitted, the first and third joint groups are permitted to operate, the joints in the second joint group do not operate, and the joints in the first and third joint groups do not operate. The joint operates based on the control data. As a result, the posture of the articulated robot is indicated by reference numeral 45 in FIG.

As described above, by combining the joint group consisting of a plurality of joints and the joint group designation data, only one or more specific joints can be controlled by communication data having a short data length. The movement of the articulated robot can be changed in various ways.

When the number of joints in one joint group is set to three, communication data can be further shortened. FIG. 7 shows an example when this mode is adopted. FIG. 7 is a diagram showing an embodiment in which the number of joints is changed. In the example shown in FIG. 7, a multi-joint robot having a total of 12 joints is divided into three joints from the top and four sets of three joints. The types of commands and control data are the same as in the case of adopting the form of FIG. The joint group designation method in the joint group designation data G also adopts the form of FIG. 6 except that 1 or 0 is arranged in four digits so as to correspond to the first to fourth joint groups. Same as when.

Since the joint group designation data G of the joint control signal denoted by reference numeral 51 in FIG. 7 is "1000", only the joints in the first joint group operate based on the control data. I have. As a result, the attitude of the articulated robot indicated by reference numeral 52 in FIG. 7 is exactly the same as the attitude 43 in FIG. As described above, the number of joints per one joint group can be increased or decreased according to the joint that actually operates, and the communication data length can be freely adjusted. Further, the articulated robot can be controlled with communication data having a minimum required data length.

In each of the above-described embodiments, an example is shown in which the joint numbers (serial numbers 1 to 12) match the installation order, that is, an example in which a plurality of joints are determined as a set of joint groups in the installation order. However, the present invention is not limited to such a limitation, and the order in which the joints are installed can be appropriately changed. For example, when the twelve joints are divided into three joint groups as shown in FIG. 3, the joints with joint numbers 2, 7, 4, and 12 are set as the first joint group, and the joint numbers 9, 5, 3 , 1 may be set as a second joint group, and joint numbers 8, 10, 11, and 6 may be set as a third joint group.

Further, in each of the above-described embodiments, the articulated robot having 12 joints and all joints having the same axial direction is used, but the joint use form is not limited to this. However, the number of joints and the axial direction of each joint can be appropriately changed. Further, a program for causing each joint to perform a joint-specific operation can be incorporated in the joint driving means 23 of each joint. That is, the control data in the joint control signal may be a code indicating a combination of a plurality of operations, and each joint may sequentially execute the operation corresponding to the code. By adopting this configuration, the operation pattern of the articulated robot can be increased.

[0047]

As described above, according to the present invention, the number of control data for each joint in the joint control signal may be the same as the number of joints in one joint group. May be a variable-length communication data format whose length changes according to the number of joints in the joint group. Therefore, the number of control data to be sent at one time can be reduced, and the command cycle can be shortened, as compared with the conventional control in which control data for all joints is sent at once.

Therefore, it is possible to increase the number of operations per fixed time of the articulated robot, and to perform precise control.

According to another invention of dividing the numerical value of the serial number of the own joint by the number of joints in one joint group and selecting control data from the remainder, the corresponding control data in the joint control signal is calculated. Since the selection can be made, the control data of the own joint can be accurately selected even if the length of the communication data format changes. Therefore, precise control by the articulated robot can be accurately performed.

According to another invention in which the joint group designation data is added to the joint control signal, the joint group to be controlled can be designated while adopting a variable length communication data format. Can be controlled in a short command cycle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a joint driving unit used in a control device for an articulated robot according to the present invention.

FIG. 2 is a diagram for explaining the operation of a data selection unit.

FIG. 3 is a diagram for explaining the operation of the articulated robot.

FIG. 4 is a diagram showing another embodiment of the data selection means.

FIG. 5 is a diagram showing another embodiment of the data selection means.

FIG. 6 is a diagram for explaining the operation of the articulated robot.

FIG. 7 is a diagram showing an example in which the number of joints per joint group is changed.

FIG. 8 is a block diagram showing a conventional control device for an articulated robot.

FIG. 9 is a block diagram of a joint driving unit.

FIG. 10 is a diagram for explaining the operation of the joint driving means.

[Explanation of symbols]

3 Serial data line, 22 Control means, 23 Joint driving means, 24, 41, 51 Joint control signal, 27
Control data.

Claims (3)

[Claims] 1. A plurality of joint driving means arranged at each joint of an articulated robot to drive a joint, a signal line connecting these joint driving means in series, and a joint control signal transmitted to the signal line. Control means for transmitting the joint control signal, wherein the joint control signal comprises: a number of joints for setting a plurality of joints as a set of joint groups in the order of a predetermined joint number; Control data of the joints in the group of joints arranged in the order of the numbers, and the joint driving means is provided with data selecting means for selecting the control data of the corresponding joint from the joint control data in the joint control signal. A control device for an articulated robot. 2. The control device for an articulated robot according to claim 1, wherein the data selecting means converts the numerical value of the corresponding joint number among the serial numbers assigned to all the joints in the order of installation by the number of joints for setting a joint group. A control device for a multi-joint robot, comprising a calculating means for dividing, and using a remainder of the division performed by the calculating means as a joint position in a joint group and selecting control data of the joint position. 3. The control device for an articulated robot according to claim 2, wherein the joint control signal has joint group designation data in which symbols indicating presence / absence of control in all joint groups are arranged in the order of installation of the joint groups. The multi-joint robot is characterized in that the data selection means detects the presence or absence of control of the corresponding joint group from the joint group designation data with the quotient of the division performed by the arithmetic means as the position of the joint group. Control device.