Two concerns for the deployment of two stage actuators in disk drives are microactuator saturation and data recovery in the event of outright microactuator failure. Compensators designed for good performance with two intact actuators may be unstable when the microactuator saturates or stops working entirely. This paper develops a modification of the PQ Method to guarantee stable operation in th...

The dynamic problems of a microactuator with a single edge crack are numerically formulated using radial basis functions. The microactuator model incorporates the taper ratio, electrode shapes, and crack length, all of which govern the dynamic behavior of microactuators. To optimize the design of a microactuator, many characteristics of various shaped cantilevers and curved electrodes are also ...

The paper proposes and develops a novel smart ER microactuator with inherent position feedback mechanism. The microactuator consists of a pair of movable and fixed parallel plate electrodes with variable gap length and an upstream restrictor, and ERF (electro-rheological fluid) is supplied as a working fluid. By applying voltage to the electrodes, with the increased pressure drop due to ERF vis...

Positioning the read-write head in a hard disk drive over data bits at densities now approaching 1 terabit per square inch will novel servo configurations and controllers. This paper presents a MEMS microactuator for installation in a dual-stage servo system for a hard disk drive and controller designs that utilize the microactuator to suppress vibration of the servo arm. The microactuator uses...

We study the dynamics of an electrostatically driven impact microactuator. Impact between moving elements of the microactuator is modeled using the coefficient of restitution. Friction between the microactuator and its supporting substrate is modeled using the Amonton-Coulomb law. We consider the bifurcations under changes in the driving voltage and frequency. Grazing bifurcations introduce dis...

This paper discusses the design and fabrication of a prototype MEMS microactuator and vibration sensors, and controller design for suspension vibration compensation in disk drives. The microactuator utilizes parallel-plates actuation and comb-finger position sensing. An electrical isolation MEMS fabrication technique is utilized to increase the actuation force. An LQG method is proposed for vib...

The importance of mechanotransduction for physiological systems is becoming increasingly recognized. The effect of mechanical stimulation is well studied in organs and tissues, for instance by using flexible tissue culture substrates that can be stretched by external means. However, on the cellular and subcellular level, dedicated technology to apply appropriate mechanical stimuli is limited. H...

We report a novel MEMS fiber scanner with an electrothermal silicon microactuator and a directly mounted optical fiber. The microactuator comprises double hot arm and cold arm structures with a linking bridge and an optical fiber is aligned along a silicon fiber groove. The unique feature induces separation of resonant scanning frequencies of a single optical fiber in lateral and vertical direc...

The development of a rotary microactuator supported on encapsulated microball bearings and driven by electro-pneumatic actuation is reported. The encapsulated bearing provides full support to an encased rotor, while an electro-pneumatic thrust balance is used to minimize rotor normal load. By minimizing normal load, bearing friction is reduced leading to increased speed and performance. Experim...

This paper presents a microactuator that utilizes osmosis to produce mechanical actuation without consuming any electrical energy. The microactuator is made of cellulose acetate with cylindrical chamber of 500 to 2000 m in diameter and of 200 to 1000 m in depth. Sodium chloride is chosen as the osmotic driving agent to be placed inside the chamber. A semipermeable diaphragm made of cellulose ac...