Search

EP-4169672-B1 - MULTI-AXIS SERVO CONTROL SYSTEM

EP4169672B1EP 4169672 B1EP4169672 B1EP 4169672B1EP-4169672-B1

Inventors

  • CHEN, CHIEN-DA
  • TSAI, I-HSUAN
  • LEE, CHIA-HUA
  • HUANG, CHING-WEI

Dates

Publication Date
20260506
Application Date
20220321

Claims (9)

  1. A multi-axis servo control system, comprising: a plurality of motors (200), and a plurality of drive control apparatuses (100) connected to each other through an external field bus (300), with each drive control apparatus (100) comprising: a control unit (10), and a plurality of drive units (20) connected to the control unit (10) in series by a plurality of local buses (400) to form a series-connected communication loop of sequentially transmitting data; characterized in that the control units (10) are connected to each other through the external field bus (300), wherein the control units (10) are configured to operate in a slave operation mode and to operate in a master operation mode; wherein in the slave operation mode, the control units (10) are configured to receive multi-axis commands through the external field bus and to provide the multi-axis commands to the drive units (20) in the same drive control apparatus (100) as that of the control unit (10); wherein in the master operation mode, the control units (10) are configured to receive the multi-axis position commands through the external field bus (300), generate the multi-axis commands and then correspondingly provide the multi-axis commands to drive units (20) in the same drive control apparatus (100) as that of the control unit (10) and in other drive control apparatuses (100) as that of the control unit (10), and wherein the drive units (20) are configured to correspondingly receive multi-axis commands through the local buses (400) so as to control the plurality of motors (200) in a decentralization manner; wherein each drive unit (20) is configured to control at least one of the plurality of motors (200) and at least one drive unit (20) is configured to control a plurality of motors (200).
  2. The multi-axis servo control system as claimed in claim 1, wherein the local bus (400) is configured to start with an output end (out) of the control unit (10), connect in series to the drive units (20) in sequence, and finally feedback to an input end (in) of the control unit (10) as the end to form the series-connected communication loop of sequentially transmitting data.
  3. The multi-axis servo control system as claimed in claim 2, wherein each drive unit (20) comprises a processor and the control unit (10) comprises a processor (402), the series-connected communication loop comprises the processor of the control unit (10), the output end (out) of the control unit (10), an input end (in) of each drive unit (20), the processor of each drive unit (20), an output end (out) of each drive unit (20), the input end (in) of the control unit (10), and the processor of the control unit (10).
  4. The multi-axis servo control system as claimed in claim 1, wherein the control unit (10) comprises: a command processor (102), and a command synchronizer (104) connected to the command processor (102).
  5. The multi-axis servo control system as claimed in claim 1, wherein the control unit (10) comprises: a command generator (101), a command processor (102) connected to the command generator (101), and a command synchronizer (104) connected to the command processor (102).
  6. The multi-axis servo control system as claimed in claim 1, wherein each drive unit (20) comprises: a current loop unit (25) configured to receive a current command and a current value, and compare the current command with the current value to generate a current control signal.
  7. The multi-axis servo control system as claimed in claim 6, wherein each drive unit (20) further comprises: a command process unit (23) configured to receive the current command, and process the current command, and a command synchronization unit (24) connected to the command process unit (23), configured to receive the processed current command, synchronize the processed current command, and provide the synchronized current command to the current loop unit (25).
  8. The multi-axis servo control system as claimed in claim 6, wherein each drive unit (20) further comprises: a current process unit (22) configured to receive the sampled current value, process the sampled current value, and provide the processed current value to the current loop unit (25).
  9. The multi-axis servo control system as claimed in claim 6, wherein each drive unit (20) further comprises: a feedback process unit (27) configured to receive a plurality of feedback commands, perform communication packet processing on the feedback commands, and provide the processed feedback commands to an output of the local bus (400).

Description

BACKGROUND Technical Field The present disclosure relates to a multi-axis servo control system, and more particularly to a multi-axis servo control system with decentralized control of the position command and the current command. Description of Related Art The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. EP 3 842 881 A1 discloses a distributed motor control system including multiple servo amplifiers that individually control multiple motors that coordinately drive an industrial machine, each of at least two servo amplifiers included in the multiple servo amplifiers has a sharing processing part that performs sharing processing for sharing coordinated control data required for coordinated drive of the industrial machine between the at least two servo amplifiers via data communication, and a control part that controls the corresponding motor using the coordinated control data that has been sharing-processed. US 2021/157320 A1 discloses a motor control apparatus which includes a main CPU configured to output a position command value, a plurality of integrated circuits connected to the main CPU and provided depending on the number of a plurality of motors, and a plurality of sub-CPUs connected to the plurality of corresponding respective integrated circuits, wherein each of the plurality of integrated circuits includes a motor interface control unit that outputs a drive command value to an amplifier that drives each of the motors in such a way as to move the motor to a position of the position command value. Each of the plurality of sub-CPUs controls an output of the drive command value by the motor interface control unit in the integrated circuit connected to the sub-CPU, based on the position command value and a position feedback value of the motor being read via the integrated circuit connected to the sub-CPU. Please refer to FIG. 1 and FIG. 2, which show a schematic structural diagram of a first type of a multi-axis servo control system of the prior art and a schematic structural diagram of a second type of a multi-axis servo control system of the prior art, respectively. As shown in FIG. 1, the first type adopted is that a single independent servo drive controls the rotation of a single motor, which means that one servo drive controls the rotation of one motor. For example, but not limited to one example shown in FIG. 1, three servo drivers 100A are used in cooperation with the corresponding three motors 200A. In this type of application, one servo driver 100A is connected to another servo driver 100A through a field bus 300A, and therefore each servo driver 100A can receive the control command from a host controller (or a host computer), and then control the corresponding motor 200A. In particular, the field bus 300A may be, for example, but not limited to, EtherCAT, CANOpen, PROFINET, or so on. Each servo driver 100A at least includes a controller and a power module. The controller is used to plan and control the speed of the motor, and the power module is used to provide the current output of the servo driver. However, in this type of control system, since each motor 200A is controlled by the corresponding servo driver 100A, in multi-axis applications, the synchronization is limited by the communication cycle of the field bus 300A, so that the synchronization is poor. As shown in FIG. 2, the second type adopted is that a single independent servo drive controls the rotation of multiple motors. For example, but not limited to one example shown in FIG. 2, one servo driver 100A is used in cooperation with the corresponding three motors 200A. However, as long as the output current (power) of the servo driver 100A can drive and control the motors 200Aand maintain normal operation, the servo driver 100A can control more than three motors. Similarly, one servo driver 100A is connected to another servo driver 100A through the field bus 300A, and each servo driver receives control commands from the host controller through the field bus 300A. However, due to the limitation of the output current (power), the upper limit of the number of motors 200A or the rated output of the motor 200A has been limited when the servo driver 100A is designed, and therefore its expandability and replaceability are poor. SUMMARY An object of the present disclosure is to provide a multi-axis servo control system to solve the problems of existing technology. In order to achieve the above-mentioned object, the multi-axis servo control system according to appended claim 1 is provided. Advantageous embodiments are the subject of the dependent claims. Accordingly, the multi-axis servo control system provides the following features and advantages: 1. The distribution calculations realized by the processing and control of the current (torque) command by the drive unit and the processing and control of the position (speed) command by the control