Self-balancing Two-Wheel Vehicle System

The natural unstable two-wheel vehicle is a special kind of wheeled mobile robot. Its dynamics equations are multi-variable, non-linear, serious coupling and uncertain parameters etc. So it is ideal that various control methods are studied on this platform. The robot is small in mechanism and can make a flexible motion. So it is fit for tasks in narrow and dangerous space and has a wide foreground both in civilian and military application. The subject aims to develop a two-wheel self-balancing vehicle. The device of this system is a parallel arrangement of two single wheels, like a traditional inverted pendulum. Because of itself natural instability, it must be exerted strong control to make it stable. It works as follows:system attitude sensors (gyroscopes and accelerometers) monitor body condition and the state in which the pitch change rate, high-speed central processing unit to calculate the appropriate data and instructions, the motor produces forward or backward to achieve the body balancing result.In this paper, studies on self-balancing two-wheel vehicle at home and abroad are summarized. And in the absence of subjects required and formed, we select the appropriate controller, motors and sensors to design two-wheel self-balancing vehicle drive circuit. And it accomplishes the entire hardware control system.Because of gyro drift problems and slow dynamic response of the accelerometer, for gesture detection system, separate usage of gyro or accelerometer can not provide effective or reliable information to reflect the real state of its body. In this paper, the data collected by the two sensors are optimized to compensate the drift error of gyroscope and accelerometer dynamic error so that the inclination of its body can be approximated better.Since that the real vehicle body is not accomplished, the control algorithms can not be studied on this basis. In order to study the control strategy in advance and shorten the design cycle, the paper has to take advantage of the LEGO robot as test platform, build vehicle model required, get mathematical modeling of the system by Newton's laws and obtain the corresponding state equation through its linearization. On this basis, the two different control strategies, namely, PID technology and pole placement technique are described in details, and finally the pole configuration is verified that it has better control effect through experiments.