**2. Walk control approach**

This section integrates the muscle emulator into the knee joint control laws. The model of our biped robot consisted of six active degrees of freedom within each leg. Each knee is driven using a 90‐W DC motor (Maxon RE‐35) with 1/90 gear. The biped robot is simulated using the Open Architecture Humanoid Robotics Platform (OpenHRP) simulator. The muscle emulator is implemented to control the DC motor in the low‐level control mode without altering the high‐level robot controls. The high‐level controls include a walking algorithm based on a state machine that provides a stable 3D dynamic biped walk. The walking algorithm and muscle emulator are coded using C++ in the OpenHRP simulator.
