A Bipedal Wheel-Legged Robot with Improved Balancing and Disturbance Rejection Capability Assisted by Electrical-Jets

This paper proposes an innovative bipedal wheel-legged robot with Electrical-Jet (E-Jet) assistance for improved balancing and disturbance rejection capabilities. Current bipedal wheel-legged robots, which are typical underactuated systems, lack control authority in terms of external disturbance rejection, thereby threatening its critical balancing functionality. Flywheels can enable robots to control their angular momentum; however, we cannot use batteries or payloads to make flywheels due to stringent manufacturing requirements. Dummy mass designs such as tails may have a similar effect. However, they are difficult to control; the associated control authority is also limited. In comparison, E-Jets or propellers can provide large thrust forces with limited weight. Therefore, we adopt the more compact E-Jets design to assist the bipedal wheel-leg robot to improve its disturbance rejection capability. We propose a simple decoupled design that can fully exploit E-Jet capability, and also develop a neat decoupled control structure to minimize the displacement caused by external disturbances. We perform comparison experiments using high-fidelity simulation to validate the effectiveness and overall performance of our proposed design.