Frequency and Speed Setting for Energy Conservation in Autonomous Mobile Robots

Autonomous mobile robots have been achieving significant improvement in recent years. Intelligent mobile robots may detect hazardous materials or survivors after a disaster. Mobile robots usually carry limited energy (mostly rechargeable batteries) so energy conservation is crucial. In a mobile robot, the processor and the motors are two major energy consumers. While a robot is moving, it has to detect an obstacle before a collision. This results in a real-time constraint: the processor has to distinguish an obstacle within the traveled time interval. This constraint requires that the processor run at a high frequency. Alternatively, the robot’s motors can slow down to enlarge the time interval. This paper presents a new approach to simultaneously adjust the processor’s frequency and the motors’ speed to conserve energy and meet the real-time constraint. We formulate the problem as non-linear optimization and solve the problem using a genetic algorithm for both continuous and discrete cost functions. Our experiments demonstrate that more energy can be saved by adjusting both the frequency and the speed simultaneously.