Motion control for variable stiffness SLIP model of legged robot single leg

The Spring Loaded Inverted Pendulum (SLIP) model has been extensively investigated and used as an inspiration to the study of legged locomotion. Biological data suggest that legs regulate energy production and removal via adjusting muscle stiffness, therefore the classical SLIP is energetically conservative model, and cannot fully explain the robustness and flexibility of many legged animals during running and hopping gaits. In this work we extend the classical SLIP model to an active SLIP model, an energetically non-conservative model with variable stiffness spring. Additionally, we propose a control strategy to regulate the SLIP system energy to drive the system to a desired motion state. Finally, we illustrate through simulations that the variable stiffness SLIP model is applied with our proposed control strategy reveals high tracking accuracy and rapidly converges to a desired motion state.