8.18 Traditional Method Control Interface

Please ensure that both the main body drive and traditional motion control are started. Toggle the H key on the handle to the right to switch states via the following ROS service, issue velocity commands via topic. Remote control buttons and joysticks will be invalid (only the C key 'freeze' is valid). Return H to the center position to restore remote control functionality.

8.18.1 Motion Mode Switching

• Interface Name: /hric/motion/set_motion_mode

• Type: service

• Description: Request to switch motion modes, applicable to all Tienkung Walker series.

• Publishing Module: Motion Control

• Client Module: Robot Management

• Message Type: hric_msgs/SetMotionMode.srv

  Service msg	Parameter Name	Parameter Type	Required	Remarks
  Request Fields	walk_mode_request	uint8	Yes	# Requested motion mode to switch, 0: start 1: stop 2: zero 3: stand 4: walk
  	is_need_swing_arm	bool	Yes	Whether arm swinging is needed for walk, true: needed, false: not needed (due to operation version, locomotion does not control arms, so setting true or false both work)
  Response Fields	sucess	bool	Yes	Indicates whether the service call was successful
  	error_code	uint32	Yes	Error code NONE=0 UNKNOWN=400

• Example Commands

  cd ros2ws
  source install/setup.bash
  # Freeze:
  ros2 service call /hric/motion/set_motion_mode hric_msgs/srv/SetMotionMode "{walk_mode_request: 1, is_need_swing_arm: false}"
  
  # Zero Position:
  ros2 service call /hric/motion/set_motion_mode hric_msgs/srv/SetMotionMode "{walk_mode_request: 2, is_need_swing_arm: false}"
  
  # Stand:
  ros2 service call /hric/motion/set_motion_mode hric_msgs/srv/SetMotionMode "{walk_mode_request: 3, is_need_swing_arm: false}"
  
  # In-place Step (After zero position is placed on the ground, directly calling this interface can enter in-place step state from zero state, but it is dangerous, do not operate this way. First enter stand state, then enter in-place step):
  ros2 service call /hric/motion/set_motion_mode hric_msgs/srv/SetMotionMode "{walk_mode_request: 4, is_need_swing_arm: false}"
  
  # In-place Run:
  ros2 service call /hric/motion/set_motion_mode hric_msgs/srv/SetMotionMode "{walk_mode_request: 5, is_need_swing_arm: false}"
  

8.18.2 Vector Velocity Control Interface

• Interface Name: /hric/robot/cmd_vel

• Type: topic

• Description: Publish velocity commands to control robot movement, applicable to all Tienkung Walker series.

• Publishing Module: Remote Control

• Subscribing Module: Robot Management

• Message Type: geometry_msgs/TwistStamped.msg

  geometry_msgs/msg/TwistStamped structure is as follows:
  std_msgs/Header header
  geometry_msgs/Twist twist
  
  Among them, geometry_msgs/Twist structure is as follows:
  geometry_msgs/Vector3 linear
  geometry_msgs/Vector3 angular
  
  linear represents linear velocity (unit m/s), x represents forward/backward movement, y represents left/right translation.
  
  angular represents angular velocity (unit rad/s), z represents rotation around the z-axis (left turn, right turn).

• Message Frequency: 20hz

• Publishing Examples:

  cd ros2ws
  source install/setup.bash
  
  # x-direction velocity is 0.15, i.e., move forward at 0.15 speed
  ros2 topic pub /hric/robot/cmd_vel geometry_msgs/msg/TwistStamped "{header: {frame_id: 'base_link' }, twist: {linear: {x: 0.15, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}}"
  
  # x-direction velocity is 0.20, i.e., move forward at 0.20 speed
  ros2 topic pub /hric/robot/cmd_vel geometry_msgs/msg/TwistStamped "{header: {frame_id: 'base_link' }, twist: {linear: {x: 0.20, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}}"
  
  # All linear and angular velocities are 0.0, i.e., in-place step
  ros2 topic pub /hric/robot/cmd_vel geometry_msgs/msg/TwistStamped "{header: {frame_id: 'base_link' }, twist: {linear: {x: 0.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}}"
  
  # Turn left at 0.1 angular velocity
  ros2 topic pub /hric/robot/cmd_vel geometry_msgs/msg/TwistStamped "{header: {frame_id: 'base_link' }, twist: {linear: {x: 0.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.1}}}"
  
  # Turn right at 0.1 angular velocity
  ros2 topic pub /hric/robot/cmd_vel geometry_msgs/msg/TwistStamped "{header: {frame_id: 'base_link' }, twist: {linear: {x: 0.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: -0.1}}}"
  
  # Finally, to make the robot enter in-place step state again, call the interface once more, passing 0.0 for both linear and angular velocities
  

8.18.3 Robot Lower Limb Motion Status Publication

• Interface Name: /hric/motion/status

• Type: topic

• Description: Publish motion control module status and velocity

• Publishing Module: Motion Control

• Publishing Frequency: 20hz

• Subscribing Module: Robot Management, Positioning, Navigation

• Message Type: hric_msgs/MotionStatus.msg

  Parameter Name	Parameter Type	Required	Remarks
  header	Header	Yes	Timestamp and coordinate system
  velocity	geometry_msgs/Twist.msg	Yes	Robot waist coordinate system velocity
  walk_mode	uint8	Yes	Walking state, 0:stop, 1:zero, 2:zero_2_stand, 3:stand, 4:stand_2_walk, 5:walk, 6:start
  is_console_control	bool	Yes	Whether it is remote control operation, true: remote control operation false: navigation operation
  is_swing_arm	bool	Yes	Whether it is walk arm swing state.
  error_code	uint32	Yes	Error code NONE=0 UNKNOWN=400

• Message Format Example:

  {
    "header": {
      "seq": 1,
      "stamp": {
        "secs": 1622548800,
        "nsecs": 0
      },
      "frame_id": ""
    },
    "velocity": {
      "linear": {
        "x": 1.0,
        "y": 0.0,
        "z": 0.0
      },
      "angular": {
        "x": 0.0,
        "y": 0.0,
        "z": 0.0
      }
    },
    "walk_mode": 6,
    "error_code": 0
  }