Computation, sensing, and communication are the most energy-intensive functions(propulsion and control are not).

Drive energy represents only a small fraction of the total energy consumed. Based on this, ways to improve the maximum reach of the robot, increase the speed of the robot, or extend the duty cycle (the ratio of driving time to total mission time) were identified.

So far, several ways to actuate mobile robots have been developed, i.e., mechanical, electrical, hydraulic, or pneumatic. In each case described, the control and detection systems need electricity. In the case of hydraulic and pneumatic systems, servo valves are electrically controlled to achieve fluid flow to the actuator from a pressure tank and to release pressure from the actuator’s other end to enable motion. In the case of electrical drive, the control of current and voltage applied to the motor windings provides ways of controlling speed, acceleration, and torque produced by such actuators.

This implies a need for electrical supply in any modern robotic system configuration. In a purely electrically actuated robot, the same supply can be used for the actuation system and control system; however, care must be taken to ensure the power rail for the control and sensors is free from interference from the noisy motor drivers. This effect can be provided, for example, by using an additional power source for the control and detection system.

The proposed division of sources by the way they generate and store energy includes the following functional categories:
  • Energy storage—including batteries, capacitors, and super capacitors;
  • Energy generation—including classical electromagnetic generators, fuel cells, and solar cells;
  • Energy harvesting—including electrochemical, wireless, thermoelectric, photovoltaic and nano-generators.