Gaussian Process-Enhanced, External and Internal Convertible (EIC) Form-Based Control of Underactuated Balance Robots

External and internal convertible (EIC) form- based motion control (i.e., EIC-based control) is one of the effective approaches for underactuated balance robots. By sequentially controller design, trajectory tracking of the ac- tuated subsystem and balance of the unactuated subsystem can be achieved simultaneously. However, with certain conditions, there exists uncontrolled robot motion under the EIC-based control. We first identify these conditions and then propose an enhanced EIC-based control with a Gaussian process data- driven robot dynamic model. Under the new enhanced EIC- based control, the stability and performance of the closed- loop system are guaranteed. We demonstrate the GP-enhanced control experimentally using two examples of underactuated balance robots.