Minimum-energy trajectory planning for differential-driven wheeled mobile robot

Abstract

With the remarkable progresses in robotics, mobile robots can be used in many applications, including exploration in unknown areas, search and rescue, reconnaissance, security, military, rehabilitation, pick up and delivery, and cleaning. Mobile robots usually carry their energy source, such as batteries with limited energy capacity; their applications are hence limited by the finite amount of energy in the batteries they carry because a new supply of energy while working is impossible, or at least too expensive to be realistic. Energy conservation can be achieved in several ways, for example, using energy-efficient motors, improving the power efficiency of motor drivers, and finding better trajectories. Despite efficiency improvements in motors and motor drivers, the operational time of mobile robots is still limited in their reliance on the batteries with finite stored energy. Hence the use of energy-efficient control for the mobile robots is required for it to survive for a longer working time. In this dissertation, we study the minimum-energy trajectory planning for differential-driven WMR minimizing the input energy drawn from the batteries. Since there are limitations by obstacles or walls in real world, we consider the bound of path-deviation, which limits deviations from the given configuration, and hence obstacles can be avoided. First, we investigate the minimum-energy trajectory generation without path planning to analyze the characteristics of energy optimal velocity profile. To determine the energy efficiency obtainable, we compare the simulations of minimum-energy control with that of loss-minimization control considering armature resistance loss. To validate the simulations, we conduct actual experiments using Pioneer 3-DX robot. Second, we investigate the minimum-energy turning trajectory planning problem with assumption of symmetric turning path to connect two translational sections surrounding rotational section since WMR needs rotation...