Abstract:As a multi input and multi output system, two wheeled self balancing robot has been used in many daily applications, but most of the researches only focus on achieving balance through experiments or using simple mathematical models. Therefore, in order to study the complete mathematical model modeling and motion balance controller design of the two wheeled self balancing robot, the state space model of the robot motion is deduced based on the motor model, wheel model and pendulum model of the robot; the controllability and observability of the system are analyzed, and the feedback controller with state estimation is designed by combining state estimation and feedback control, At the same time, LQR control method is introduced to improve the control effect of the controller in robot motion. The simulation results show that the feedback controller with state estimation and LQR control method have good stability and robustness for this kind of self balancing robot.