Design of a two-wheeled mobile robot using series elastic actuators

초록

In this paper, we propose a method to implement a new type of two-wheeled mobile robot equipped with active suspension control using series elastic actuators to maintain vehicle body stability while moving in an uneven environment. First, the design structure of the robot incorporating a series of elastic actuators was described. Then, a model in which the acceleration of the robot body is the control input of the system was derived to ensure robust balance control of the robot. For active suspension control, we derived a mathematical model of a series elastic actuator based on Newton's law. The proposed robot uses the pitch angle obtained from the IMU sensor to achieve balance control and uses a Linear Quadratic Regulator (LQR) controller to obtain the input acceleration required for stabilization. In the active suspension control, a seriess of elastic actuators is applied to the legs of the robot to measure the external force transmitted from the road surface to the wheel while moving, and the impedance controller is applied accordingly. The output value from the impedance controller serves as a reference for the ball screw up and down movement speed to control the speed of the DC motor. Finally, from experimentation, it was found that the mobile robot using the proposed method maintains good balance for both the pitch angle and roll angle on an uneven surface. © ICROS 2020.

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