An efficient sigmoidal class topper optimization-based PID controller for human knee exoskeleton system

Many people face knee problems due to conditions like osteoarthritis, obesity, post-polio syndrome, strokes, ligament injuries, or accidents. To assist with movement, artificial knee exoskeleton systems are often used. This paper proposes an optimal proportional-integral-derivative (PID) controller for accurate control of the angular movement of such devices. Additionally, a sigmoidal class topper optimization (SCTO) technique is designed to optimally tune the PID controller for knee exoskeleton systems. The convergence performance of the SCTO algorithm is tested on various CEC 2005 benchmark functions and compared with existing methods. When applied to the knee exoskeleton system, the SCTO-based PID controller demonstrated improved control performance compared to other algorithms.