Non-contact Electrostatic Levitation of φ400mm Silicon Wafer

Mizuno

et al. 2012

JSDD

Voltage control using a variable capacitor and floator position estimation are proposed for designing a low-cost electrostatic suspension control system. When an electrostatic actuator and a variable capacitor are connected in series to a constant power supply, the voltage applied to the suspension system can be changed by varying the capacitance of the variable capacitor because the electrostatic suspension system can be treated as a capacitor. Moreover, the voltage is determined by these capacitances and so the floator position can be estimated from the voltage applied to the suspension system and the capacitance of the variable capacitor. The proposed voltage control system enables electrostatic suspension without a high-voltage amplifier or direct floator position detection. Therefore, this control system can reduce the total cost of electrostatic suspension systems. The principle of the proposed self-sensing control is described using a basic electrostatic suspension model. The position of the floator was estimated according to this principle. Self-sensing suspension was achieved by feeding back the estimated signal.

Section: Introductionmentioning

confidence: 99%

Self-Sensing Control of Electrostatic Suspension Using Variable Capacitor

Mizuno

et al. 2012

JSDD

“…These electrostatic actuators play a critical role in microelectromechanical systems (MEMS) because the static force per unit volume increases when the size of the object becomes small [1] . In addition, several studies on suspension and transportation using electrostatic actuators have been reported [1]- [5] . Transportation without contact is important for the next generation of industrial technology.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Suspension Using Variable Capacitors

Tsukada

et al. 2009

JSDD

A new control system for electrostatic actuators was applied to electrostatic suspension. This control system was designed to use a variable capacitor connected with an electrostatic actuator in series. A high voltage was applied to this connection. The voltage applied to the actuator was controlled by varying the capacitance of the variable capacitor. An experimental apparatus was fabricated in order to study the controllability of electrostatic force using this control system. The experimental results show that electrostatic force can be controlled both statically and dynamically. Another experimental apparatus was fabricated for demonstrating the feasibility of electrostatic suspension. This apparatus was able to control the 3-DOF vertical motions of the suspended object. Non-contact suspension was achieved with the developed control system using variable capacitors.

“…Several researches considered this problem. One of them is ON-OFF control (7) . As another method, we have suggested voltage control using variable capacitor (8) .…”

Section: Introductionmentioning

confidence: 99%

“…In order to achieve electrostatic suspension, voltage control system is necessary. The voltage applied to electrodes reaches several kilo volts in suspending wafers (7) . The required voltage is determined by the suspension gap and the weight of the wafer.…”

Section: Introductionmentioning

confidence: 99%

Double Electrostatic Suspension System

Mizuno

et al. 2012

JSDD

Multiple electrostatic suspension suspends multiple floators with a single power amplifier. The controllability of double parallel suspension was previously analyzed and the conditions to be controllable were shown. To ensure the analytical results, single-DOF suspension systems were fabricated, and a double parallel electrostatic suspension system consisted of these systems. The feasibility of double parallel electrostatic suspension was demonstrated experimentally. Dynamic characteristics of double parallel electrostatic suspension were studied based on step responses and frequency responses.