Linear Drive Based on Silicon/Ethanol Composite

The paper presents a concept of an actuator, based on a silicon/ethanol composite placed in the brass bellows. Such actuator is operating based on a change in the physical state of ethanol, which is enclosed in bubbles surrounded by a matrix of silicone rubber. In this paper, the prototype of the actuator is described, and a series of its test results, in the open and closed loops, are presented. Two laser distance-sensors, with different accuracies, were used as a source of the feedback signal. During the investigations the temperature of the actuator was also measured. This has allowed us to determine the delay in heat flow from the heater to the composite. In the closed loop, P- and PI-type controllers were used in the drive positioning experiments. It was discovered that in the closed loop control, it was possible to achieve a positioning error of less than 200 µm. During the tests, the temperature inside the drive and the ambient temperature were also measured. In order to improve the dynamics of the drive, a small fan was used, controlled by the automation system. It allowed us to shorten the time to return the drive to its starting position. The results of frequency tests of the drive have also been presented.