Novelmicro Transportation Systems Based on Ratchetmechanism and Electrostatic Actuators (original) (raw)
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Journal of Microelectromechanical Systems, 2000
This paper presents a novel micro transportation system (MTS), which can drive micro containers in both straight and curved paths based on an electrostatic comb actuator and a ratchet mechanism. The micro container, which has four driving wings and four anti-reverse wings attached to its central 'backbone', is driven to move forward only by an electrostatic actuator. While the driving wings act as the legs of a water strider to push the container forward, the anti-reverse wings work as a ratchet mechanism to prevent the container from moving backward. The container with a length, width and thickness of 500 μm, 250 μm and 30 μm, respectively, moves unidirectionally with a desirable velocity up to 1000 μm s −1 in straight and curved paths. The velocity can be changed by varying the frequency and/or amplitude of the driving voltage. The MTS has been fabricated from SOI (silicon on insulator) wafer utilizing silicon micromachining technology with only one mask.
2007
This paper describes a Si micro transportation system (MTS) to drive micro containers in straight movement based on a ratchet mechanism and electrostatic comb-drive actuators. This MTS consists of linear comb actuators, micro containers and ratchet racks. The lateral movements of ratchet racks push the micro containers which move straight in a perpendicular direction with different velocities. The MTS was fabricated from a SOI wafer by using only one mask. In our experiments, the movement of the micro container has been tested with driving frequency ranges from 1 Hz to 20 Hz. The velocity of the micro container was proportional to the driving frequency, and it matched well with the theoretical calculation.
A micro gearing system based on a ratchet mechanism and electrostatic actuation
Microsystem Technologies, 2013
This paper presents the design and fabrication of a silicon micro gearing system (MGS) that utilizes electrostatic comb-drive actuators to rotate a gear ring through a ratchet mechanism. The rotational comb-drive actuator is engaged with the gear ring through a spring system and ratchet teeth at one end, reciprocally rotates around an elastic point at the other end based on the electrostatic force. Rotational motion and torque from the driving gear ring are transmitted smoothly to driven gears through involute-shaped gear teeth. Smart design of antigap structures helps to overcome the unavoidable gap problem occurred in deep reactive ion etching (deep-RIE) process of silicon. The MGS has been fabricated and tested successfully by using SOI (silicon-on-insulator) wafer and one mask only. The angular velocity of the gear ring is proportional to the driving frequency up to 40 Hz.
Single mask, simple structure micro rotational motor driven by electrostatic comb-drive actuators
Journal of Micromechanics and Microengineering, 2012
We report a design and fabrication of a new micro rotational motor (MRM) using silicon micromachining technology with the overall diameter of 2.4 mm. This motor utilizes four silicon electrostatic comb-drive actuators to drive the outer ring (or rotor) through ratchet teeth. The novel design of the anti-reverse structure helps us to overcome the gap problem after deep reactive ion
Micro Transportation Systems: A Review
Modern Mechanical Engineering, 2011
This paper summarized and reviewed recent studies of micro transportation systems (MTS) in the MEMS (Micro Electro-Mechanical System) field. Micro transportation systems can be identified and classified into three categories based on the contact types between the objects and the actuators (i.e. liquid-based, solidbased and air-bearing type). Their advantages and disadvantages were also analyzed and compared. The authors have proposed and developed three types of solid-based MTS utilizing electrostatic comb-drive actuators and ratchet mechanisms to drive the micro container in straight and curved paths. These MTSs have been fabricated with silicon-on-insulator (SOI)-MEMS technology and tested successfully. In the near future, MTSs can be applied in different fields such as medicine (to classify and test blood cells), in bioengineering (to capture, sort and combine bio-cells, DNA), or in micro robot systems.
A fabrication process for electrostatic microactuators with integrated gear linkages
Journal of Microelectromechanical Systems, 1997
A surface micromachining process is presented which has been used to fabricate electrostatic microactuators. These microactuators are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear structures, and the electrostatic microactuators include curved electrode actuators, comb-drive actuators, and axial-gap wobble motors. The micromechanical structures are constructed from polysilicon. Silicon dioxide was used as a sacrificial layer, and silicon nitride was used for electrical insulation. A cyclohexane freeze drying technique was used to prevent problems with stiction. The actuators, loaded with various mechanisms, were successfully driven by electrostatic actuation. The work is a first step toward mechanical power transmission in micromechanical systems. [213]
High-Angular-Range Electrostatic Rotary Stepper Micromotors Fabricated With SOI Technology
Journal of Microelectromechanical Systems, 2000
Flexible bearings are advantageous for microelectromechanical systems as they enable precise, accurate, repeatable, and reliable motion without frictional contact. Based on the principle of a rotary folded-beam suspension, we have designed, fabricated, modeled, and characterized an electrostatic rotary stepper micromotor in silicon. Using 3-D finite-element analysis simulations that were corroborated by extensive characterizations performed in quasi-static, transient, and dynamic regimes, we could establish a consistent electromechanical model of the motor. In particular, dynamic nonlinearities such as superharmonic and subharmonic resonances are well described by the proposed model. Two prototypes of monolithic three-phase stepper motors have been fabricated with standard silicon-on-insulator (SOI) technology, using either a two-mask or a single-mask process. The two-mask SOI motor has a rotor diameter of 1.4 mm and has an angular range of 30 • (±15 • ) for a 65-V (130 V pp ) sinusoidal actuation. The single-mask SOI motor has a rotor diameter of 1.8 mm and incorporates a differential capacitive sensor for angular position measurement. It reaches a maximum angular speed of 1 • /ms and has an angular range of 30 • for a 23-V (46 V pp ) sinusoidal actuation. The exceptional performance of the motor and the demonstration of successful capacitive sensing make it suitable for use as an active joint module in future microrobotic applications.
IEEE Transactions on Education, 2000
A laboratory course on the theory, fabrication, and characterization of microelectromechanical systems (MEMS) devices for a multidisciplinary audience of graduate students at the University of New Mexico, Albuquerque, has been developed. Hands-on experience in the cleanroom has attracted graduate students from across the university's engineering and science campuses, including students from the Nano-Science and Micro Systems program, itself an interdisciplinary program. This course has been offered yearly for the last four years (since 2007) at the University of New Mexico. In one project from the class, a MEMS actuator is fabricated. This paper details the theory, fabrication steps, and characterization of a silicon-on-insulator (SOI) comb drive actuator that relies on fixed-fixed beams for its restoring force. Discussions include force generation by comb drives and a linear and nonlinear description of the restoring force applied by the fixed-fixed beams. Course assessment data is given from 79 students from three semesters, based on which the effectiveness of the laboratory project is evaluated.
2007 International Symposium on Micro-NanoMechatronics and Human Science, 2007
motors to move a sliding shuttle. In this case, the This paper presents a novel micro transportation driving mechanism requires at least two groups of system (MTS), which can drive micro carts by bidirectional XY actuators which were turned on and off utilizing electrostatic actuator and ratchet at suitable times, alternately holding and driving a mechanism. The micro cart, which has driving-wings shuttle. In another work [5], Fujimasa reported the and anti-reverse-wings attached to its central integrated actuator which was actuated by vibration and 'backbone', is driven by electrostatic actuator