Robust Agility and Safety for Dynamic Aerial Manipulation and Legged Locomotion - Koushil Sreenath
From Katie Gentilello
Biological systems are able to move with great elegance, agility, and efficiency in a wide range of environments. Endowing machines with similar capabilities requires designing controllers that can address the challenges of high-degree-of-freedom, high degree- of-under actuation, nonlinear dynamics, while simultaneously enforcing constraints of available actuators, sensors, and processors. In this talk, I will present the design of planning and control policies for two problems — dynamic aerial manipulation and dynamic legged locomotion. First, I will show how a coordinate-free, geometric mechanics formulation of the dynamics of a quadrotor carrying a suspended payload allows us to synthesize nonlinear geometric controllers with almost-global stability properties for aggressive maneuvers. I will present the problem of cooperative transportation of a cable-suspended payload using multiple aerial robots, and show how we can design dynamically feasible trajectories that can handle hybrid dynamics resulting from the cable tension going to zero. Next, I will present the design of control policies for dynamic bipedal locomotion by explicitly considering the nonlinear and hybrid dynamics of bipedal robots subject to input torque constraints, contact force constraints, and safety-critical constraints. This design is achieved through control Lyapunov and Barrier functions. In addition, I will show that the adverse of effects of model uncertainty on both stability and constraint enforcement can be addressed through a robust formulation of control Lyapunov and Barrier functions.