A multi-slider linear actuator using modulated electrostatic attraction and inertia effect

This paper proposes a linear actuator with multiple sliders, which utilizes modulated electrostatic attraction and inertia effect. AC voltages are applied between the sliders and a vibrating rod to produce electrostatic attraction force such that friction force can be modulated. Combined with the vibration that is synchronized with the electrostatic attraction, the actuator can drive the sliders linearly on the rod. By providing different friction patterns to the multiple sliders through the electrostatic attraction, the actuator can realize independent motions of the sliders on the same single rod. Different friction patterns are realized by independently controlling the voltage phases. This paper reports on the basic principle, analytical results, and experimental prototype utilizing a voice coil motor as the vibration source. The velocity characteristics measured on the prototype verified the analytical results that predicted the velocity changes sinusoidally against the phase shift between the electrostatic attraction and the rod vibration. Using the prototype, the independent motions of two sliders were demonstrated, which include same directional motions and opposite motions. It was also demonstrated that one slider is kept stationary during a motion of the other slider.