Maxon motor with EPOS4 vibrates in CSP Mode

[alesof]

Hi there!

I am trying to control a maxon motor using the Epos4 driver and this ethercat/ROS2 framework. I'm sending through a custom node a fixed increment in position at each timestep, the motor moves in the correct direction, but vibrates, has someone had the same issue or can point me to a fix?

The active ros2 interface is a position controller (position_controllers/JointGroupPositionController). This is the configuration file I'm using for the drive:

vendor_id: 0x000000FB                                                                                 # Vendor ID
product_id: 0x61500000                                                                                # Product ID
revision: 0x01700000                                                                                  # Revision            
assign_activate: 0x0300                                                                               # DC Synch register
auto_fault_reset: true


sdo:                                                                                                  # SDO data to be transferred at drive startup
 - {index: 0x60C2, sub_index: 1, type: int8, value: 10}                                               # Set interp time for cyclic modes to 10 ms
 - {index: 0x60C2, sub_index: 2, type: int8, value: -3}                                               # Set base 10-3s

rpdo:                                                                                                 # RxPDO = receive PDO Mapping
  - index: 0x1600
    channels:
      - {index: 0x6040, sub_index: 0, type: uint16, default: 0}                                       # Control word
      - {index: 0x6060, sub_index: 0, type: int8, default: 8}                                         # Mode of operation
      - {index: 0x607a, sub_index: 0, type: int32, command_interface: position, default: .nan}        # Target position
      - {index: 0x60ff, sub_index: 0, type: int32, command_interface: velocity, default: .nan}        # Target velocity

      ## HOMING PARAMETERS
      - {index: 0x6098, sub_index: 0, type: int8, default: 17}                                        # Homing method
      - {index: 0x6099, sub_index: 1, type: uint32, default: 1000}                                    # Homing speed
      - {index: 0x609A, sub_index: 0, type: uint32, default: 10000}                                   # Homing acceleration

tpdo:                                                                                                  # TxPDO = transmit PDO Mapping 
  - index: 0x1A00
    channels:
      - {index: 0x6041, sub_index: 0, type: uint16}                                                    # Status word
      - {index: 0x6064, sub_index: 0, type: int32, state_interface: position}                          # Position actual value
      - {index: 0x606c, sub_index: 0, type: int32, state_interface: velocity}                          # Velocity actual value
      - {index: 0x6077, sub_index: 0, type: int16, state_interface: effort}                            # Torque actual value
      - {index: 0x6061, sub_index: 0, type: int8, default: 8}                                          # Modes of operation display

[pzanne]

What is the resolution of your encoder?
Could you modify the file ethercat_generic_cia402_drive/src/generic_ec_cia402_drive.cpp as follows:

 if (pdo_channels_info_[index].index == CiA402D_RPDO_POSITION) {
    if (mode_of_operation_display_ ! = ModeOfOperation::MODE_NO_MODE) {
      if (state_ <= STATE_SWITCH_ON ) {
            pdo_channels_info_[index].default_value =
              pdo_channels_info_[index].factor * last_position_ +
              pdo_channels_info_[index].offset;
      } 
    }
    pdo_channels_info_[index].override_command =
      (mode_of_operation_display_ != ModeOfOperation::MODE_CYCLIC_SYNC_POSITION) ? true : false;
  }