A Novel Bi-Stable Force Sensor: Theory and Modeling

2009 ◽  
Author(s):  
Pezhman A. Hassanpour ◽  
Patricia M. Nieva ◽  
Amir Khajepour
Keyword(s):  
Analytical Model ◽  
Axial Force ◽  
Applied Voltage ◽  
Electrostatic Force ◽  
Force Sensor ◽  
Time Response ◽  
Constant Rate ◽  
New Type ◽  
Linear And Nonlinear ◽  
Theory And Modeling

In this paper, a novel sensing mechanism is introduced. This mechanism consists of a clamped-clamped beam and two parallel electrodes. An analytical model of the system, that takes into account the mechanical linear and nonlinear stiffnesses as well as the nonlinear electrostatic force, is developed. The time response of the system to a disturbance is derived while the applied voltage is increasing at a constant rate. It has been shown that the voltage, that destabilize the beam, can be used as a measure of the axial force in the beam. This technique can be used in the development of new type of sensors.

a-Si:H/a-SiC:H Heterostructure for Bias-Controlled Photodetectors

1994 ◽  
Vol 336 ◽  
Author(s):  
G. De Cesare ◽  
F. Irrera ◽  
F. Lemmi ◽  
F. Palma ◽  
M. Tucci
Keyword(s):  
Applied Voltage ◽  
Energy Gap ◽  
The Other ◽  
Time Response ◽  
Wavelength Selection ◽  
Load Impedance ◽  
Amorphous Si ◽  
Hydrogenated Amorphous ◽  
High Rejection

ABSTRACTWe present a novel family of photodetectors based on hydrogenated amorphous Si/SiC p-i-n-i-p heterostructures. Front p-i-n and rear n-i-p diodes work one as a detector and the other as a load impedance, depending on the polarity of the applied voltage. Due to different absorption at different wavelengths, the devices operate as bias-controlled light detectors in either the blue or the red regions. The energy gap and the thickness of the two intrinsic layers have been optimized to obtain a sharp wavelength selection (centered at 430 and 630 nm) with high rejection-ratios and good quantum efficiencies. The I-V characteristics and the device time response are investigated and simulated by SPICE.

Development of a Novel Micro-Gripper Integrating Tri-Axial Force Sensor

2007 ◽  
Author(s):  
Jiachou Wang ◽  
Weibin Rong ◽  
Lining Sun ◽  
Hui Xie ◽  
Wei Chen
Keyword(s):  
Axial Force ◽  
Crystalline Silicon ◽  
Force Sensor ◽  
Calibration Method ◽  
Deep Reactive Ion Etching ◽  
Micro Gripper ◽  
The Cross ◽  
Silicon Frame ◽  
High Level ◽  
Cross Structure

A novel micro gripper integrating tri-axial force sensor and two grades displacement amplifier is presented in this paper, which bases on the technology of Piezoresistive detection and use PZT as its micro driving component. The micro tri-axial force sensor is fabricated on a single-crystalline-silicon by the technology of MEMS and consists of a flexible cross-structure realized by deep reactive ion etching (DRIE). The arms of the cross-structure are connected to a silicon frame and to the central part of the cross-structure. After modeling the amplifier structure of micro gripper and the sensor, finite element method (FEM) is used to analyze the displacement of the micro gripper and the deformation of the cross-structure elastic cantilever. A calibration method of tri-axial sensor based on the technology of microscopic vision and the principle of bending deflection cantilever is proposed. The experimental verified that the sensor are high level of intrinsic decoupling of the signals from strain gauge, high resolutions in all three axes, high linearity and repeatability and simple produce of calculation. And also show the micro gripper is reasonable and practical. The sensor is capable of resolving forces up to 10mN with resolution of 2.4μN in x axis and y axis and up to 10mN with resolution of 4.2μN in z axis; the gripping displacement of the micro gripper is from 20μm to 300μm.

Design and characterization of a silicon piezoresistive three-axial force sensor for micro-flapping wing MAV applications

2015 ◽  
Author(s):  
Wei Zhang ◽  
Van T. Truong ◽  
Kim B. Lua ◽  
A. S. Kumar ◽  
Tee Tai Lim ◽  
...  
Keyword(s):  
Axial Force ◽  
Force Sensor ◽  
Flapping Wing

Design and Analysis of Hemispherical Electrostatic Micro Deformable Focusing Mirror

Volume 3 ◽  
2004 ◽  
Author(s):  
Shang-Wei Tsai ◽  
Meng-Ju Lin
Keyword(s):  
Applied Voltage ◽  
Electrostatic Force ◽  
Focal Length ◽  
Length Change ◽  
Least Square ◽  
Limit Values ◽  
Etching Depth ◽  
Isotropic Etching ◽  
Length Changes ◽  
Structure Layer

For uniform deformation, based on bulk microfabrication with isotropic etching, two types of hemispherical electrostatic micro deformable focusing mirror are designed. One of the focusing mirrors is center-anchored, and the other is circular clamped. Using theory of shells, theoretical solution of deformation under uniform electrostatic force is derived. For more detail analysis of the electrostatic and elastic forces coupling problem, finite element is used to analyze the deformation of the mirror structure. Applying electrostatic force, the profile of micro focusing mirror will be not the spherical and change to become a curve like parabolic surface. Using least square method, the curve is fitted as a parabolic curve and the focal lengths of the focusing micro mirror are obtained. The result shows the focal length without applying electrostatic force can be determined by different micro mirror radius and isotropic etching depth. When the electrostatic forces are applied, the deformation and the focal length change differently between the two types of focusing mirror. For circular clamped micro mirror, the deformation is larger near circular clamped region and uniform in the center regime. Therefore, the relation of focal length and applying voltage is a concave curve with minimum values. That is, the focusing length decreasing as the applying voltage increasing and reaches a limit values. When the applying voltage continues increasing after reaching the minimum value, the focal length increases fast. It also shows the thicker structure layer needs larger applied voltage. But the focal length changes in larger stroke. The pull-in voltage is about 100 volt when the structure layer are both 2 μm. However, the pull-in voltage increases nonlinearly as gap increasing. When the gap increases to 4 μm, the pull-in voltage is about 300 volt. The result shows center-anchored micro mirror has better performance. The deformation is more uniform and the focal length increases nonlinearly as applied voltage increasing. It is found the stroke of focal length is larger and the applied voltage is less. The results shows even when the gap and structure layer is 4 and 2 μm, the pull-in voltage is about 62 volts. However, the stoke changes from 990 to about 1320 μm when applying voltage is from 0 to 60 volts. Therefore, with low applied voltage and large focal length stoke, the center-anchored micro mirror has good performance.

Linear Friction Damper Consisted of Cylindrical Block and Inclined Lever (Improvement to Avoid Sprag-Slip Problem and Analytical Model to Verify Cause)

2011 ◽  
Author(s):  
Hideya Yamaguchi ◽  
Hidehisa Yoshida
Keyword(s):  
Analytical Model ◽  
Friction Force ◽  
Friction Damper ◽  
Friction Forces ◽  
Constant Friction ◽  
Linear Friction ◽  
New Type ◽  
Passive Isolation ◽  
Isolation Systems ◽  
Cylindrical Block

For the passive isolation systems, the ordinary friction damper of constant friction force has performance limitations. This is, because the isolation characteristic declines and the displacement remains apart from the equilibrium position after the disturbance disappears, when the friction force is large. It is known that the above drawbacks are improved when the friction force varies depending on the displacement. The authors have proposed a new type of friction damper in our previous paper. This friction damper uses an inclined lever, which contacts the cylindrical block by means of a rotational spring. The angle of inclination of the lever varies together with the displacement of the cylindrical block. Then, the normal and friction forces on the contact surface vary depending on the displacement. However, “Sprag-slip” vibration occurred in some cases in the experiments. This paper investigates the cause of the vibration and a design to prevent it. Then, an analytical model is proposed to simulate the problem and to estimate the effect of improvement.

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