In a not too distant future, assistive robots will become a natural part of the human society, in hospitals, schools, elder care facilities, inner city urban areas, and eventually homes. While wheeled robots, e.g., a humanoid torso on a mobile platform, can cover a range of tasks that assistive robots will be needed for, eventually, legged robots will be the most suitable, as legs increase the effective workspace of a robot and allow maneuvering more complex terrains like steps, curbs, and cluttered and rough terrains in general. This project investigates biped locomotion with a Sarcos humanoid robot. In contrast to most other projects in biped locomotion, it emphasizes walking over uneven and rough terrain, obstacle avoidance, recovery from unexpected perturbation, and learning methods for motor control, as these issues seem to be the most important for working in dynamic and partially unpredictable human environments. Another focus is on dexterous movement control, i.e., control with a maximal amount of compliance and minimal negative feedback gains, using advanced operational space controllers with internal model control. Dexterous, compliant control will increase safety of the robot when accidentally impacting with humans or obstacles, and it will also allow the robot to recover more easily from external perturbation simply by ?giving in?. Such a control approach requires departing from the traditional high-gain position controlled humanoid systems, and focuses on torque control, reactive instantaneous control instead of finite horizon optimization, as well as efficient motion planning and learning methods.
