Abstract
In this thesis, modeling, design, and control issues associated with a pedaled and self-balanced personal mobility vehicle are studied. The vehicle, named Legway, is structurally similar to a pedaled unicycle but uses a brushless DC (BLDC) hub motor as its main driving wheel. The lateral balance and steering of the vehicle is controlled manually by the rider via a passive steering mechanism including a handle, a rotational joint, cables, pulleys, and so on. In order to balance, to steer, and to safely drive Legway on slippery road, three research issues are studied. First of all, to longitudinally balance Legway, a balancing controller with center of gravity (COG) adaptation capability is proposed, and the associated control synthesis method utilizing linear matrix inequality (LMI) is developed. Using this controller, Legway can automatically place COG of the rider plus the vehicle frame right above wheel axle so as to minimize the interference between the balancing motor torque and the rider’s pedaling torque. Secondly, to maintain lateral balance and steer Legway, the dynamics of the passive steering mechanism of Legway is modeled. Simulations on the dynamic model allow one to select crucial design parameters to enhance steering performance. Finally, to drive Legway safely on slippery road, an anti-slip compensator is proposed to cooperate with the balancing controller. Such a compensator provides appropriate compensating action to the balancing controller so that it can maintain its stability in the presence of tire slip. A synthesis method is proposed to design the gain matrix in the compensator and to analyze the stability of the overall system. The design and control concepts presented are verified by simulations or experiments. The work of the thesis can greatly facilitate the development of intelligent and green personal mobility vehicles.