Comprehensive Bond Graph Modeling and Optimal Control of an Anthropomorphic Mechatronic Prosthetic Hand

Abstract

This paper presents comprehensive modeling, simulation and optimal control of an anthropomorphic mechatronic prosthetic hand comprising of 20 DOF. To acquire the mathematical model of the robotic hand, the graphical modeling technique known as the bond graph has been used. Bond graph provides precise dynamic model of complex systems, with relatively fewer computations and ease as compared to other modeling techniques. Precise modeling leads to better control performance which is essential for prostheses. In this research, firstly, linear quadratic (LQ) controller has been designed for desired movements of fingers of robotic hand with optimal control energy. Secondly, the system is formulated as an H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> optimal control problem in which the Gaussian noise is introduced at the input and output and an optimal H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> controller is designed for system stability in the presence of noise. Graphical modeling is carried out by using the 20-sim software and the mathematical equations of the system are obtained. These equations are then imported to MATLAB <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> where the optimal controllers have been implemented and simulated. The closed loop feedback dynamic responses of index finger (flexion and extension movements) for both the controllers have been presented and analyzed. The results show that the optimal controllers have provided the desired output in terms of stability.