Optimization Design and Performance Analysis of a Bionic Knee Joint Based on the Geared Five-Bar Mechanism

Area of Science:

• Robotics
• Biomechanics
• Mechanical Engineering

Background:

• Animal joints exhibit complex rotation and translation for stability and energy efficiency.
• Hinge joints in legged robots are limited in motion performance due to fixed-axis rotation.
• Kangaroo knee joints offer a model for advanced robotic joint design.

Purpose of the Study:

• To develop a bionic geared five-bar knee joint mechanism for legged robots.
• To improve energy utilization and reduce driving power requirements.
• To enhance robot motion performance, particularly in running and jumping gaits.

Main Methods:

• Image processing to determine the kangaroo knee joint's instantaneous center of rotation (ICR) trajectory.
• Design and parameter optimization of a single-degree-of-freedom geared five-bar mechanism.
• Dynamic modeling of a robot leg using the inverted pendulum model and Newton-Euler method.

Main Results:

• The bionic geared five-bar knee joint closely tracks desired center of mass trajectories.
• The mechanism demonstrates abundant motion characteristics superior to traditional hinge joints.
• Significant reduction in power demand and energy consumption for robot knee actuators was observed.

Conclusions:

• The bionic geared five-bar knee joint offers improved motion performance for legged robots.
• This mechanism effectively reduces actuator power and energy consumption during dynamic gaits.
• The design provides a viable alternative to conventional hinge joints for enhanced robotic locomotion.