Stability of the two-wheeled inverted pendulum vehicle moved by human pedaling

Abstract

In order to tackle with the problems surrounding the environment, the aged society and the individual mobility right, the new type of vehicle which is compact and convenient is expected to be developed. The authors have been investigated such a vehicle called Personal Mobility Vehicle (PMV), which is friendly for human and the environment. In this paper, we proposed the two-wheeled inverted pendulum vehicle moved by human pedaling. The basic mechanism of this new vehicle consists of the system of the stabilization control for inverted pendulum and the pedaling torque by a human. This system has following benefits. It realizes the longer usage of battery than the conventional one thanks to the human power. It is a healthy vehicle due to the pedaling and the seating style makes the driver longer travel than standing. From the academic point of view, it is very important to investigate the interaction with the control of the two-wheeled inverted pendulum vehicle and the human motion. We analyzed the two types of the drive system. One is the mechanical drive system and the other is the electric drive system. The mechanical drive system has the chains between the gear at the pedal and the gears at the wheels. The in-wheel motors are used for the stabilization. As for the electric drive system, the electric generator generates electricity by pedaling and the produced energy is stored by the battery. The in-wheel motors are rotated by the electricity comes from the battery. In the numerical simulation, the vehicle is stabilized by an optimal controller. The influence of the constant pedaling torque and variable one on the stabilization control were compared. It was shown that the variable pedaling torque became the disturbance to the inverted pendulum vehicle and the torque for the stabilization would be necessary according to the disturbance. Therefore, it is found that the electric drive system which drives the in-wheel motors by the less varying torque command from the battery is more effective than the mechanical drive system that directly convey the human power to the wheels. Finally, we confirmed the basic motion of the proposed vehicle by using the prototype vehicle. The vehicle was successfully stabilized by the controller and moved by the human pedaling.