Artificial Muscles Harvesting Sensational Power Using Self-Sensing

摘要

Dielectric elastomer Generator(s) (DEG) are highly suited to harvesting from environmental sources because they are light weight, low cost, and can be coupled directly to rectilinear motions and harvest energy efficiently over a wide frequency range. Because of these benefits, simple and low cost generators could be enabled using DEG. Electrical energy is produced on relaxation of a stretched, charged DEG: like-charges are compressed together and opposite-charges are pushed apart, resulting in an increased voltage. The manner in which the DEG charge state is controlled greatly influences the amount of energy that is produced. For instance, the highest energy density ever demonstrated for DEG is 550 mJ/g, whereas the theoretical energy density of DEG has been reported as high as 1700 mJ/g if driven close to their failure limits. The discrepancy between realised and theoretical energy production highlights that large performance gains can be achieved through smarter charge control that drives the generator close to its failure limits. To do so safely, we need to be able to monitor the real-time electromechanical state of the DEG. This paper discusses the potential of self-sensing for providing feedback on the generator's electromechanical state. Then we discuss our capacitive self-sensing method which we have demonstrated to track the displacement of a Danfoss Polypower generator as it was cyclically stretched and harvested energy.