Design of a hip joint trajectory tracking controller for an exoskeleton

Artificial walking aids are a common type of assistive technology used by the disabled. The purpose of this article is to introduce empirical tuning of a proportional-integral-derivative controller (PID) for the right hip joint of a six-degree-of-freedom lower limb exoskeleton. The experimental setup consists of an electro mechanical structure which includes, a leg movement drive system, and a central control module that coordinates the walking action. A master controller generates the joint reference angle trajectory, while a slave controller tracks the same. As shown in the experimental results, the experimental setup's actual hip joint angle satisfactorily followed the reference trajectory with minimum kinematic error.