Design and Hybrid Control of a Two Wheeled Robotic Platform

As the level of human interaction with robotic systems increases, robot mobility becomes more important. Two wheeled robots offer higher levels of mobility and manoeuvrability when compared to their four wheeled counterparts with the ability to turn on the spot and easily negotiate tight corners. Whilst the stabilisation of two wheeled platforms has been well studied, there is no published research on alternative actuation methods. This study proposes the implementation of a reaction wheel actuator to balance a two wheeled platform within small angular deviations from its equilibrium position. It is proposed that the use of a reaction wheel to deliver the balancing torque instead of the platform drive wheels will lower energy consumption of the system. This hypothesis was derived from the idea that there are fewer energy losses in delivering the torque from the reaction wheel in comparison to the platform wheels. After the design and construction of the platform, standardised tests were carried out to make energy consumption comparisons between the reaction wheel actuated (hybrid) system and the traditional baseline system. The results from these experiments showed that the hybrid system consumed approximately 21% less energy than the baseline system and therefore proves the feasibility of adding a reaction wheel actuator to the system. Index Terms ---Reaction wheel, robotics, state-space control, linear quadratic regulator, energy efficient balancing.