Inverse-kinematics-based control of a redundantly actuated platform for rehabilitation

The paper introduces the control of a redundantly actuated parallel mechanism for ankle rehabilitation which is based on online inverse kinematics calculation to generate required actuating parameters to control the mechanism and achieve the required dynamic response. The geometry of the mechanism is described and the design parameters are investigated in the analysis of singularity and dexterity. The dynamic model is developed and the tuning of the control gains is performed by analysing the level of actuation conflict and tracking error that have been minimized by varying the controller parameters. The paper further examines the actuation conflict and evaluates its association with the control parameters. Both simulation and experiments were carried out to implement the analysis and control strategy in the mechanism.