7-DOF Robotic Arm Motion Planning Algorithm Development for Humanoid Robots

Jul 15, 2025·
Zilin Chen 陈子林
Zilin Chen 陈子林
· 1 min read

Project Overview

Core Objective: Develop motion planning algorithms for Xiaomi’s 7-DOF humanoid robotic arm, enhancing motion precision (<0.3mm error), stability, and robustness against payload variations.
Technical Framework:

  • Theoretical Basis: DH parameters, inverse kinematics (IK), trajectory interpolation
  • Toolchain: MuJoCo simulation, C/Python co-development
  • Validation Protocol: Dual verification system complying with ISO 9283 standards (positioning accuracy, path repeatability)

Key Technical Achievements

  1. Kinematics Algorithm Development
    • Forward Kinematics: Established DH-based coordinate transformation model with 0.1mm calculation precision
    • IK Solver Optimization:
      • Developed universal inverse kinematics interface auto-adapting to URDF configurations
      • Hybrid numerical-geometric solution reducing end-effector positioning error to 0.3mm
    • Trajectory Smoothing: Implemented Kalman filtering with B-spline interpolation, decreasing joint velocity fluctuations by 30%
  2. Simulation-Physical Validation
    • MuJoCo Environment: Calibrated dynamic parameters (gravity compensation, joint friction models) matching h1_2 hardware specs
    • Hardware-in-the-Loop Validation: <1.5% deviation in 50 test trajectories between simulation and physical tests
trajectory planning image
trajetory planner with filter
enduable error image enduable error image
enduable test results demo

System Optimization

Three-Core Enhancement Strategy:

  1. Fail-Safe Mechanism: Collision detection triggering 10ms emergency stop
  2. Computational Efficiency: optimized code achieving 1kHz control frequency

Strategic Recommendations:

  1. Engineering: Implement fault injection testing for failure mode analysis
  2. Collaboration: Establish knowledge-sharing platform for URDF optimization