Experiment of robust driving assistance control for skid steer welfare vehicle using model error compensator

Recently, welfare vehicles are widely used by patients and elders indoors, and many welfare vehicles with free casters drive indoors. However, the vehicle with free casters may not be able to move well on gravel or dirty road as seen in rural yard. In order to expand driving area for welfare vehicles, it is necessary to apply a new mechanism on the rough road. To design compact welfare vehicles for outdoor use at low cost, the skid steer mechanism is focused on. The skid steer vehicle (SSV) has been used for its high traveling ability on rough road. However, the SSV has disadvantage that the maneuvering assistance is required because its steering is highly affected by road condition. This study aims a driving assistance of SSV for patients and elders by using Model Error Compensator (MEC) that suppresses the modeling error. The proposed controller consists of MEC, Extended Kalman Filter (EKF) that reduces sensor and system noise assuming the undulating and skiddy gravel road, and estimation of cornering power of SSV. The effectiveness of the proposed control system is confirmed by the outdoor driving experiment comparing asphalt and gravel roads.