Minimum Energy Control Based on Vector Parameterization for Four-Wheel Drive Omni-Directional Mobile Robots

Abstract

Four-wheel drive omni-directional mobile robots (FDOMRs) usually carry limited energy and have to accomplish their tasks before deadlines. Energy saving can be achieved in several ways, and one of that is determining a velocity trajectory. To find the minimum energy trajectory, a practical cost function is chosen as the total energy drawn from the batteries. However, the cost function is a free final time optimal control problem, which is usually complex and has no explicit solution. A normalized time variable is used to transform the original problem into a fixed final time optimal control problem, which is solved by using uniform control vector parameterization. Various simulations are performed and the consumed energy is compared to the normal control method that without minimum energy consumption control. Simulation results show that the energy saving is much more compared to the traditional control, the operational time of the FDOMR with given batteries is lengthened and the efficiency of battery is improved.