5.1.1 Motion Mode Switching

The mode-switch and locomotion interfaces provide core capabilities for switching motion modes and controlling walking/running.

Core Functions

Supports switching into the following basic motion modes:

Mode	Value	Description	Use cases
Zero-Torque Mode	PASSIVE_DEFAULT	Robot joints zero torque, free state	System startup, maintenance, soft e-stop
Damping Mode	DAMPING_DEFAULT	The joint exhibits a damping effect	Safe movement
Position-controlled Stand	JOINT_DEFAULT	Position-controlled stand	Precise joint position control
Stable Stand	STAND_DEFAULT	Active force to ensure standing	Dynamic balance control, walking/action ready state
Locomotion Mode	LOCOMOTION_DEFAULT	Normal walking/running	Daily movement

Note: Starting from v0.8.0, the stable-stand mode and Locomotion Mode are unified and will switch internally based on the current motion commands.

Motion Mode Query Service

Service Name	Data Type	Description
/aimdk_5Fmsgs/srv/GetMcAction	GetMcAction	Query current motion mode

• GetMcAction ros2-srv @ mc/action/srv/GetMcAction.srv

  # Get current motion mode
  # Service: /aimdk_5Fmsgs/srv/GetMcAction
  
  # Request
  CommonRequest request            # Common request
  
  ---
  
  # Response
  ResponseHeader response          # Response header
  McActionInfo info                # Information about the current motion mode
  

  • McActionInfo ros2-msg @ mc/action/McActionInfo.msg

    # Motion mode information
    McAction current_action  # Current motion mode(abandoned since v0.8.2)
    string action_desc       # Description
    McActionStatus status    # Status of the motion mode
    

    • McActionStatus ros2-msg @ mc/action/McActionStatus.msg

      int32 value  # Action status (100: running, 200: switching)
      

Motion Mode Set Service

Service Name	Data Type	Description
/aimdk_5Fmsgs/srv/SetMcAction	SetMcAction	Set motion mode

• SetMcAction ros2-srv @ mc/motion/srv/SetMcAction.srv

  # Set motion mode
  # Service: /aimdk_5Fmsgs/srv/SetMcAction
  
  # Request
  RequestHeader header             # Request header
  McActionCommand command          # Motion command
  
  ---
  
  # Response
  CommonResponse response          # Generic response; response.status.value = 1 indicates success
  

  • McActionCommand ros2-msg @ mc/motion/McActionCommand.msg

    # McActionCommand
    McAction action      # abandoned since v0.8.2
    string action_desc   # Mode description
    

Programming Examples

For detailed programming examples and code explanations, see:

• C++ Examples: Get Robot Mode Set Robot Mode

• Python Examples: Get robot mode Set robot mode

Safety Notes

Warning

• Do not use motion modes or mode descriptions that are not explicitly documented in this section.

• Ensure the robot is in a safe state before switching motion modes.

• It is recommended to test motion-control code in a simulation environment first.

• Do not deploy SDK applications on the motion-control compute unit (PC1) to avoid interfering with high real-time motion tasks.

Caution

As standard ROS DO NOT handle cross-host service (request-response) well, please refer to SDK examples to use open interfaces in a robust way (with protection mechanisms e.g. exception safety and retransmission)

Note

Best Practices

• Implement motion state monitoring and exception handling.

• Implement additional safety checks around motion control where possible.