Output Tracking Control of Mobile Wheeled Inverted Pendulum with State Estimation via Fully Actuated System Approach

The mobile wheeled inverted pendulum(MWIP) is a typical underactuated mechanical system, widely used for motion analysis in autonomous robotics and intelligent vehicles. This paper investigates the output tracking problem of the MWIP system. Since wheel speed and angular velocity cannot be directly measured, we apply the linear extended state observer (LESO) for state observation. Subsequently, the output function is reconstructed based on the state tracking error, transforming the system model into a fully actuated system where the open-loop dynamics can be eliminated straightforwardly. For the LESO, the simulation results show that the state estimated by the observer can be used to control. The controller is used to track the wheel's rotation velocity, achieving tracking errors of less than 0.1% for a constant value curve and within 2.3% for a time-varying curve which verifies the effectiveness of the controller.