Abstract
The present paper introduces a novel standing-up control strategy based on Initial Value Compensation (IVC) for a Personal Mobility Robot (PMR). PMRs, which are wheeled-inverted-pendulum-type mobility-assist devices, offer the following advantages: (1) they can turn at a point; (2) they can maintain a level seating posture on a slope; and (3) they have a smaller footprint than conventional electric wheelchairs with four wheels. On the other hand, the user must maintain the posture of the PMR by using additional assist wheels on the ground when mounting/dismounting the PMR and working while seated on the PMR. In order to satisfy these requirements, we propose the following approach. First, the PMR accelerates to lift its assist wheels off the ground and determines whether the assist wheels are in contact with the ground. The feedback controller is then switched to wheeled-inverted-pendulum mode using the proposed IVC. The proposed IVC is designed such that the transient responses are improved and the amplitude of the control input and the jerk component are suppressed, in order to reduce the shock felt by the driver. The effectiveness of the proposed approach has been verified by conducting numerical simulations and experiments using a prototype PMR.
