JP2006015420A - Control device for articulated robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an articulated robot capable of easily changing the shaft order (the order of driving shafts) in a robot body and the shaft order in a driving device. <P>SOLUTION: The control device 11 for the articulated robot for controlling the robot body 5 having a plurality of driving shafts, has a robot mechanism computing part 1 for computing at least a position and an angle in the robot body 5, and a shaft changing part 2 capable of changing the order of the plurality of driving shafts provided at the robot body, and controls the plurality of driving shafts provided at the robot body 5, by the robot mechanism computing part 1 through a shaft changing part 2. The change of servo motors among the driving shafts in the robot body 5 can thereby be easily coped with while using the conventional driving device 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control apparatus for an articulated robot that controls a robot body having a plurality of drive axes, and in particular, an articulated robot capable of switching the order of axes (order of drive axes) in the robot body and the order of axes in the control apparatus. The present invention relates to a control device.

  FIG. 3 is a perspective view showing a general 6-axis vertical articulated robot. In this vertical articulated robot, the turning frame turns about J1 with respect to the main body base, the lower arm rotates about J2 with respect to the turning frame, and the upper arm rotates about J3 with respect to the lower arm. ing. Further, the wrist (wrist) provided at the tip of the upper arm has three rotation axes and is rotatable around J4, J5 and J6 shown in FIG. Here, the drive shafts for rotating around the above-described J1 to J6 are referred to as JT1 to JT6 axes, respectively. Servo motors are used as actuators for these drive shafts.

  In the 6-axis vertical articulated robot shown in FIG. 3, generally, a servo motor having a relatively large output is used for the three drive shafts (JT1 to JT3 axes) on the main body base side. Uses a servo motor with a relatively small output for the three drive shafts (JT4 to JT6) on the opposite side, that is, the wrist side. Therefore, in a drive device such as a servo amplifier that drives each servomotor of each of the six drive shafts, the drive device that drives each of the JT1 to JT3 shafts has a relative current capacity in order to correspond to the output of the servomotor described above. On the other hand, a driving device for driving each of the JT4 to JT6 axes uses a device having a relatively small current capacity.

In the above, a servo motor with a large output is used for the JT2 axis, while a servomotor with a small output is used for the JT4 axis. When a robot body that uses a servo motor with a large output for the JT4 axis and a servomotor with a small output for the JT2 axis is newly developed, a drive unit different from the above-mentioned form is newly designed and manufactured. There was a need. Patent Document 1 discloses a technique for controlling a drive axis of a robot body by a drive device having a control axis number smaller than the number of axes of the robot body. However, this technique has a demerit that it cannot be applied to a usage pattern in which all the drive shafts of the robot body are driven synchronously.
Japanese Patent Laid-Open No. 5-293651

  As described above, in the above-described conventional technology, the servo motor of the robot body that can be driven is determined according to the current capacity of each axis of the drive device included in the control device. Therefore, for example, when considering a drive device having a relatively large current capacity on the JT1 to JT3 axes and a relatively small current capacity on the JT4 to JT6 axes, the JT1 to JT3 axes have a large output in the robot body. There is no problem if it is a servo motor and the JT4 to JT6 axes are servomotors with a small output. However, in this drive device, when the order of axes in the robot body (order of drive axes) is changed, for example, when the JT2 axis and JT4 axis in the robot body are changed, there is a problem. In other words, in this case, a servo motor with a large output is used for the JT4 axis, while a servomotor with a small output is used for the JT2 axis. The disadvantage of driving the servo motor occurs.

  The present invention has been made to solve the above-described problems of the prior art, and is an articulated robot that can easily exchange the axis order (drive axis order) in the robot body and the axis order in the drive device. An object of the present invention is to provide a control device.

  In order to achieve the above-described object, in the present invention, in an articulated robot control device that controls a robot body having a plurality of drive axes, a robot mechanism calculation unit that calculates at least a position and an angle in the robot body, and a robot body An axis exchanging unit capable of exchanging the axis order of the plurality of drive axes included in the robot, and the robot mechanism calculation unit controls the plurality of drive axes included in the robot body via the axis exchanging unit. A control device for an articulated robot is provided.

  With such a configuration, when the axis order of a plurality of drive axes included in the robot body is changed, for example, when the servo motor as the actuator of the drive axis is changed between the drive axes, the axis order of the drive axes It can be easily dealt with by the processing in the axis replacement unit that makes it possible to replace As a result, a driving device with a large current capacity drives a servo motor with a large output, and a driving device with a small current capacity drives a servo motor with a small output. The correspondence with the output of can be taken well.

  According to the present invention, it is possible to easily cope with the replacement of the servo motor between the drive shafts in the robot body while using the drive device that has been used conventionally. As described above, since the axis order in the robot body and the axis order in the drive device can be easily interchanged, the manufacturer designs and manufactures the drive device according to the difference in the arrangement of the servo motor between the drive shafts. This saves time and eliminates the need for the user to have several types of drive units as spare parts.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a control device 11 for an articulated robot according to an embodiment of the present invention. In FIG. 1, reference numeral 5 denotes an articulated robot body having six drive shafts. The structure of the robot body 5 is shown in FIG. The robot 5 is configured such that the turning frame turns about J1 with respect to the main body base, the lower arm rotates about J2 with respect to the turning frame, and the upper arm rotates about J3 with respect to the lower arm. The list provided at the tip of the upper arm is rotatable around J4, J5, and J6 shown in FIG.

  Here, the drive shafts for rotating around the above-described J1 to J6 are referred to as JT1 to JT6 axes, respectively. Servo motors are used as actuators for these drive shafts. Regarding the magnitude of the output of the servo motor, a servo motor having a relatively large output is used for the three drive shafts (JT1 to JT3 axes) on the main body base side, while the other side of the main body base, that is, the list Servo motors with relatively small outputs are used for the three drive shafts (JT4 to JT6) on the side.

  In FIG. 1, reference numeral 1 denotes a robot mechanism calculation unit that calculates at least a position and an angle on each drive axis included in the robot body 5. In general, kinematics of the robot body 5 is calculated. Reference numeral 2 denotes an axis replacement unit, which replaces drive axes in a preset order. A servo control unit 3 that performs feedback control and the like corresponds to the axis order of the driving device 4 on a one-to-one basis. Reference numeral 4 denotes a drive device that supplies a command current to a servo motor for driving each drive shaft included in the robot body 5, and this drive device 4 has a large current capacity for the JT1 to JT3 axes, and JT4 to JT6. The shaft has a small current capacity.

  In FIG. 1, the size of the notation ◯ in the driving device 4 relatively represents the current capacity of each axis. Further, the size of the notation ◯ in the robot body 5 relatively represents the output size of the servo motor of each drive shaft. Each block of the robot mechanism calculation unit 1, the axis replacement unit 2, and the servo control unit 3 is software, and each block of the driving device 4 and the robot body 5 is hardware.

  Next, with reference to the flowchart shown in FIG. 2, the flow of processing performed in the axis replacement unit 2 described above will be described. Here, in the robot body 5, a case where a servo motor with a large output is used for the JT4 axis and a servomotor with a small output for the JT2 axis is used by replacing the JT2 axis servomotor with the JT4 axis servomotor. Suppose. In the axis replacement unit 2, the following processing is performed every time a command value is transmitted to the servo control unit 3.

  First, in step 100, a preset value for axis replacement is read into the array data S []. Here, the set value for axis replacement may be determined by the manufacturer for each robot body, or may be arbitrarily changed by the user. In the array data S [], the order of data transfer to the servo control unit 3 is stored as an axis number in order from the array element zero. The array values when data is transferred to the servo control unit 3 in the order of JT1, JT2, JT3, JT4, JT5, JT6 are usually S [0] = 1, S [1] = 2, S [2] = 3, S [3] = 4, S [4] = 5, S [5] = 6. However, as described above, in this assumption, the JT2 axis servomotor and the JT4 axis servomotor are replaced in the robot body 5, and therefore the array value when transferring data to the servo control unit 3 in this assumption is In order from the element zero, S [0] = 1, S [1] = 4, S [2] = 3, S [3] = 2, S [4] = 5, and S [5] = 6.

  Next, in step 101, the axis number i is initialized to the first axis (i = 0). In step 102, if the process has been completed for all the drive axes, the series of processes is terminated (step 102 YES). If the process has not been completed for all the drive axes (NO in step 102), the process proceeds to step 103. In step 103, the axis parameter of the array S [i] axis is transferred to the servo control unit 3. Similarly, in step 104, the axis command and axis data of the array S [i] axis are transferred to the servo control unit 3. These data transfer methods include a communication method and a transfer method via a shared memory, but the details thereof are not described here because they are not the gist of the present invention.

  After performing these processes, the axis number i is incremented by 1 in step 105, and the processes in steps 103 and 104 are repeated until all axes are completed.

  According to the above processing, as shown in FIG. 1, the JT2 driving device having a large current capacity drives the JT4 servo motor having a large output, and the JT4 driving device having a small current capacity has a small output. As a result, the correspondence between the current capacity of the driving device and the output of the servo motor can be taken well. In the present embodiment, the order of these axes is assumed to be changed for the JT2 axis and the JT4 axis, but the present invention is not limited to this, and the order of the axes can be changed for any axis. .

  As described above, according to the control device of the present embodiment, the configuration of the robot mechanism calculation unit 1 and the servo control unit 3 can be changed to an arbitrary axis order while being the same as the conventional configuration. Therefore, it is possible to easily cope with the replacement of the servo motor between the drive shafts in the robot body 5 while using the drive device 4 that has been conventionally used. As described above, since the axis order in the robot body and the axis order in the drive device can be easily interchanged, the manufacturer has to design and manufacture the drive device according to the difference in the arrangement of the servo motor between the drive shafts. This eliminates the need for the user to have several types of drive devices as spare parts.

  In the above-described embodiment, the number of axes to be processed is only the drive shaft of the robot body 5, but is not limited to this. For example, when the multi-joint robot is a welding robot, a welding gun is attached to the drive shaft of the robot body. It is good also as the number of axes which combined the additional axis to drive.

It is a block diagram which shows the structure of the control apparatus 11 of the articulated robot in one Embodiment of this invention. It is a flowchart which shows the flow of the process performed in the axis replacement part 2 in one Embodiment of this invention. It is the perspective view which showed the vertical articulated robot controlled by the control apparatus of the articulated robot which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot mechanism calculation part 2 Axis exchange part 3 Servo control part 4 Drive apparatus 5 Robot main body 11 Control apparatus

Claims (1)

In a control apparatus for an articulated robot that controls a robot body having a plurality of drive axes,
A robot mechanism calculator that calculates at least a position and an angle in the robot body;
An axis changing unit capable of changing the axis order of a plurality of drive axes included in the robot body,
A controller for an articulated robot, wherein the robot mechanism calculation unit controls a plurality of drive axes provided in the robot main body via the axis replacement unit.

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