STIFF · Enhancing biomorphic agility through variable stiffness

The goal of the proposed study is to equip a highly biomimetic robot hand-arm system with the agility, robustness and versatility that are hallmarks of the human motor system by understanding and mimicking the variable stiffness paradigms that are so effectively employed by the human CNS. A key component of the study will be the anatomically accurate musculoskeletal modelling of the human arm and hand. The project will develop novel methodologies to comprehend how the human arm can adapt its impedance, e.g. by changing the co-contraction level or by adapting the reflex gains. The impedance of the arm and of the hand will be investigated using powerful robot manipulators capable of imposing force perturbations. The existing closed-loop system identification techniques will be extended with non-linear time-variant techniques which can identify the behaviour during reaching and grasping tasks. The grasp force modulation and hand muscle activity correlations will be learned for use on the robotic system. Finally, optimization techniques gleaned and validated on the detailed biophysical model will be transferred to the variable impedance actuation of the novel biomorphic robotic system The central question that this proposal focuses on for both the human and robotic arm is: how is stiffness used to enhance performance?; and this project represents one of the first attempts where targeted modelling studies will go the full circle by exploiting these results for optimal control of an embodied, high dimensional, variable impedance robotic system.