“Can you imagine robots that can harvest all the energy they need from their environment?” That’s the question Dutch researcher, Douwe Dresscher at the University of Twente asks in the video where he introduces the concept of a walking robot that, through solar panels, can harvest enough energy from the sun to work continuously without an external power supply. Of particular importance to Dresscher is the development of a walking robot capable of performing dyke inspections without the need for down time. Since dykes in the Netherlands are critical to preserving life and property, the more efficiently and consistently an inspection robot is able to do its job, the safer the population will be.
The type of environment in which dyke inspection robots operate is wet, slippery and somewhat remote. These conditions require that the robot move by walking rather than rolling in order to remain securely on a sloping surface. Walking robots, which can maintain their position on the slope but not damage the surface as a robot that moves on caterpillar tracks would do, are the solution. They generally use more energy, but conditions on the dykes make it impractical to provide charging stations for the robots. Dresscher needed to address this challenge by lowering the power demands of the robots by making them more efficient.
The solution Dresscher proposes for lowering the energy demands made by these walking robots is a system called “Controlled Passive Actuation.” In the system proposed by Dresscher, energy in the electric motors that power the robot’s legs, a substantial amount of mechanical energy is stored and reused, cutting down on the amount of additional electrical energy that must be supplied by the motor.
As Dresscher explains, “The main actuation energy is delivered by a mechanical storage element such as a flywheel or a spring. The energy flow is controlled by means of a continuously variable transmission.” In this way, the energy supplied by the electric motor is used more efficiently, performing at high revolution speeds and low torque than in a traditional walking robot system where the power is delivered at low revolution speed and high torques.
Currently, Dresscher’s system is too large to be used in a real-world application. However, the technology has great promise if it can be sufficiently miniaturized to fit in a robot capable of operating out on a dyke.
To learn more about this interesting research and to see a video of the Controlled Passive Actuation model, visit https://www.utwente.nl/en/news/!/2016/11/495390/dyke-inspection-robot-will-be-energy-autonomous