Experimental verification of the dynamic model for a quarter size self-balancing wheelchair

A quarter size scale model of the sitting-standing transporter (SST), a self-balancing wheelchair capable of supporting a person in the sitting and standing position, was designed, constructed, and tested. The scale model represents a loaded wheelchair with only two parallel wheels. The chair and a counter balance are both attached to the main axle and are free to rotate around it. In order to keep the chair in a stable position above the main axle, a state-feedback controller is used to drive the wheels and control the position of the counter balance. The controller used to stabilize the scale model in this research was a linear quadratic regulator (LQR) with five inputs and two outputs. The performance of the scale model was evaluated with five tests that represent situations that would be encountered in everyday use of the SST. These tests were also simulated using a nonlinear dynamic model and these simulation results were compared to the experimental results. Based on the comparison between simulation and experimental results, the accuracy of the dynamic model was verified. The dynamic model and the scale model can now be used to provide insights into building a full size SST.