Dynamic Position/Force Controller of a Four Degree-of-Freedom Robotic Leg

The leg controllers of a six-legged walking robot have a great influence on the walking capabilities of the robot. A good controller should create a smooth locomotion, minimize mechanical stress and soften collision impacts. This article introduces a model-based position/force controller, which is able to eliminate the negative effects of non-linear disturbances with a computed torque control approach, but also creates very smooth leg movements. An additional force feedback reduces the influences of leg collisions and is able to maintain a desired ground contact force during the stance phase.