Energy-Saving 3-Step Velocity Control Algorithm for Battery-Powered Wheeled Mobile Robots

Energy of Wheeled Mobile Robot (WMR) is usually supplied by batteries with finite energy. In order to extend run-time of battery-powered WMR, it is necessary to minimize the energy consumption. The energy is dissipated mostly in the motors, which strongly depends on the velocity profile. This paper investigates energy efficiency for typical 3-step velocity control methods to minimize a new energy object function which considers practical energy consumption dissipated in motors related to motor dynamics, velocity profile, and motor control input. We performed analyses on energy consumption for the four typical 3-step velocity profiles: S-C-S, T-C-T, S-C-T, and T-C-S (S is an acceleration/deceleration section by step control input, T is an acceleration/deceleration section by acceleration/deceleration phase of trapezoidal velocity profile, and C is a cruise section with a constant velocity). Also we suggested an efficient iterative search algorithm with binary search which can find the numerical solution quickly. We performed various computer simulations to show the performance of energy-efficient 3-step velocity control in comparison with a conventional 3-step trapezoidal profile with a reasonable constant acceleration rate as a benchmark. Simulation results reveal that the S-C-T is the most energy efficient 3-step velocity control profile, which enables WMR to extend working time up to 30%.