Development of an active balance board for progressive ankle rehabilitation

This paper presents the design and development of a single degree-of-freedom Active Balance Board (ABB) for progressive ankle rehabilitation. The stiffness and damping of the system can be varied through the gains of the implemented Proportional Derivative (PD) controller. The aim of this initial research is to tune the ABB to match the transient characteristics of a classic balance board (CBB). The dynamics of a CBB have not previously been defined and so this paper outlines the derivation for its equations of motion. Results are presented which validate that the performance of the ABB can match the CBB in the unloaded condition as well as with a 50kg subject. A method to objectively quantify the difficulty of balancing is proposed and this demonstrates the feasibility of controlling the performance of the ABB based on the clinical needs of the individual patient.