Traveling assist control of two-wheel wheelchair in unknown step passage

摘要

A two-wheel wheelchair is a wheelchair without casters. It is underactuated system, and it can be modeled as an inverted pendulum. A two-wheel wheelchair has improved former problems of a conventional four-wheel wheelchair, such as step passing capability. However, two-wheel wheelchair still requires high torque for step passage. To generate high torque command of wheel, large posture movement of passenger is required, and this leads to an operational difficulty. In this paper, traveling assist control of two-wheel wheelchair in step passage is proposed. In this proposal, virtual disturbance of pitch angle is generated according to reaction torque response of wheels. Then virtual disturbance is introduced to a Synthesized Pitch Angle Disturbance Observer(SPADO). With virtual disturbance, SPADO will generates higher torque command of wheel and allow passenger to generate high torque command of wheel with small posture movement. Validity of proposal is tested through experiment.