indy_7msgs - A2R-Lab/indy7-sdk GitHub Wiki

The indy7_msgs package provides custom ROS 2 message definitions for working with 6-DOF robotic manipulators, designed for trajectory control and state monitoring.

JointState

Represents the complete state of the robot's joints at a given moment in time.

Fields

  • header (std_msgs/Header)
    • Standard ROS2 message header containing timestamp and frame information
  • positions (float32[6])
    • Array of joint positions in radians
    • One value per joint, ordered from base to end effector
  • velocities (float32[6])
    • Array of joint velocities in radians per second
    • Matches position array ordering
  • torques (float32[6])
    • Array of joint torques in Newton-meters
    • Matches position array ordering

JointTrajectoryPoint

Represents a single knot point in a joint-space trajectory, containing position, velocity, and torque targets.

Fields

  • positions (float32[6])
    • Target joint positions in radians
    • One value per joint, ordered from base to end effector
  • velocities (float32[6])
    • Target joint velocities in radians per second
    • Matches position array ordering
  • torques (float32[6])
    • Target joint torques in Newton-meters
    • Matches position array ordering

JointTrajectory

Represents a complete joint-space trajectory consisting of multiple knot points.

Fields

  • header (std_msgs/Header)
    • Standard ROS2 message header containing timestamp and frame information
  • knot_points (uint32)
    • Number of knot points in the trajectory
  • dt (float64)
    • Time step between trajectory points in seconds
  • points (JointTrajectoryPoint[])
    • Array of trajectory knot points
    • Each point contains position, velocity, and torque targets
    • Points should be evenly spaced in time according to dt

Usage Notes

  • All joint arrays follow the same ordering convention from base to end effector
  • Angular values (positions and velocities) use radians and radians/second respectively
  • Trajectory timestamps start from the header timestamp
  • The total duration of a trajectory can be calculated as (knot_points - 1) * dt
  • The points array length in JointTrajectory should match the knot_points value