A Low-Voltage Large-Displacement Large-Force Inchworm Actuator

Abstract

Inchworm microactuators are popular in micropositioning applications for their long ranges. However, until now, they could not be considered for applications such as in vivo biomedical applications because of their high input voltages. This paper reports on the modeling, design, fabrication, and testing of a new family of pull-in-based electrostatic inchworm microactuators which provides a solution to this problem. Actuators with only 7-V operating voltage are achieved with a ±18-μm total range and a ±30-μN output force. Larger operating voltage (16 V) actuators show even better results in force (±110 μN) and range (±35 μm). The actuator has an in-plane angular deflection conversion which provides a force-displacement tradeoff and allows us to set step sizes varying from few nanometers to few micrometers with a minor change in design. In this paper, we designed 1-and 4-μm step-size devices. The actuator step size may change during the operation because of the slipping of the shuttle and the beam bending; however, our model successfully explains the reasons. One of our actuator prototypes has survived more than 25 million cycles without performance deterioration. The device is fabricated using the silicon-on-insulator-based multiuser MEMS process.[2007-0146]

A water-tight packaging of MEMS electrostatic actuators for biomedical applications

“…Furthermore, they are integrated with a microneedle (25 9 80 9 1,500 lm) to demonstrate a possible biomedical positioning application. The details of the design and fabrication are previously presented (Erismis et al 2008) (Fig. 2).…”

Non-initial overlap bulk silicon comb-drive actuator with low-voltage and large-displacement

“…In addition, the desired displacement of the comb-drive actuators is constrained by the side instability. In order to overcome this drawback, some effective approaches have been developed for a large displacement by alleviating side instability, such as optimal suspension designs [9][10][11], linearly engaging comb fingers [12][13], and appropriate first and last comb fingers [14]. However, there is scarcely comb-drive actuator that can achieve 50μm within 25V driving voltages [9][10][11][12][13][14][15][16][17].…”

High-Performance Shuffle Motor Fabricated by Vertical Trench Isolation Technology

“…As a result, electrostatic microactuators with large displacement ranges generally suffer from low output forces. Electrostatic micromotors based on stepping motion [5][6][7][8][9][10][11][12][13] are a practical solution for generating large output forces and large displacements simultaneously. These motors use a "large force-short stroke" microactuator to produce small, powerful steps.…”

“…These motors use a "large force-short stroke" microactuator to produce small, powerful steps. A clamping mechanism, either based on frictional force [5][6][7][8][10][11][12][13] or obtained with gear teeth [9], is employed to create large displacements via incremental steps. In these motors, the propulsion and the clamping are dissociated to allow for individual optimization of these two mechanisms.…”

“…Shuffle motors [8,10], contraction beams motors [12] or stepper motors with an in-plane angular inflexion conversion [13] are a few examples of such mechanisms. Shuffle motors employ electrostatic force to inflect an elastic plate and generate small, powerful steps.…”