Modelling and Optimal Control of Human Voluntary Motion in 3D for Bipedal

Abstract

Biomechanical modelling in three dimensions of human voluntary motion with motor control is an extremely important field that consists of human intended behaviors. The human body demonstrates extremely complicated motion trajectories with a very high level of mobility and degree of freedom (DOF). In this research, we have extended our 3D biomechanical model research to develop the optimal motor controls that exhibit biomechanical schemes for human sit to stand (STS) motion. The developed three modelling schemes are realized to analyze the motion constraints on rigid body model of human STS motion. Model developed in CAD software SOLIDWORKS Corp. comprising of a 3D 8-segment biped having 2 feet, 2 calf, 2 thigh, a pelvic and a HAT segment is utilized to generate the LQR based optimal control on the developed reference trajectories of each joint. Model having one foot fix and other a 1DOF prismatic joint is utilized for controller development due to its full rank controllability and observability. The optimal control is developed in MATLAB / SIMULINK after linearizing the model in SIMSCAPE / SIMULINK by importing the xml files from SOLIDWORKS. Control system utilized the feedback of position and speed of each joint and generates the torque inputs for the model based on the required reference trajectories. The developed model is of 22nd order and the results show that all the motor joints followed the reference trajectories.