In this paper, a modified U-shaped micro-actuator with a compliant mechanism is proposed. It was analyzed with a uniform and modified thin arm, as well as a similar variation in the corresponding flexure, in order to observe the impact of the compliant lumped mechanism. The use of these compliant mechanisms implies an increment in the deformation and a reduction in the equivalent stress of 25% and 52.25%, respectively. This characterization was developed using the Finite Element Method (FEM) in ANSYS Workbench. The design, analysis and simulation were developed with Polysilicon. In this study, the following performance parameters were also analyzed: force and temperature distribution. This device is supplied with voltage from 0 V up to 3 V, at room temperature. The modified U-shaped actuator was applied in both arms of a microgripper, and to evaluate its electrothermal performance, a static structural analysis has been carried out in Ansys Workbench. The microgripper has an increment in deformation of 22.33%, an equivalent stress reduction of 50%, and a decrease in operation frequency of 10.8%. The force between its jaws is of 367 µN. This low level of force could be useful when sensitive particles are manipulated.

Microelectromechanical (MEM) Accelerometers measure the accelerations or vibrations experienced by objects due to inertial forces or mechanical excitations. To improve their proof mass displacement, several alternatives have been used, such as the design of different shapes of suspension beams. In this work, a new shape of beam is proposed based on alternated segments of different widths. To analyze its performance, one-quarter, middle and complete accelerometers were calculated and simulated; the results were compared with similar cases using conventional uniform-shaped beams. A notable improvement in the proof mass displacement was obtained in all cases, especially with the proposed symmetrical-shaped beam. Harmonic response and explicit dynamic analysis were also considered to discover performance when they are subjected to structural load. An improvement in amplitude displacement was also observed, as well as operation frequency reduction. From the explicit dynamic analysis, a faster performance of the accelerometer with uniform arms can be observed; however, it responds at a lower range of input velocities. A performance comparison of the proposed beam is presented considering the two reported accelerometers. Finally, from the variation in the width of the thinner segment of the symmetrical arms, it can be observed that it is possible to obtain an increment in the displacement of the proof mass of 39.57% and a decrement in natural frequency of 15.30%, with respect to the case of the uniform arm. Other advantages of the symmetric beam are the stress distribution, reducing its effect on the proof mass, as well as their low cross-axis sensitivity. Simulations were performed with ANSYS.

A Novel Displacement-amplifying Compliant Mechanism Implemented on a Modified Capacitive Accelerometer

In this paper, the dynamic and electric analysis of a novel electrostatically actuated microdevice is presented. This device consist of an arrangement of four parallel microcantilevers, which is fed with 1 V. The analysis was carried out by Finite Element Method (FEM) in Ansys Workbench in order to obtain: current intensity, temperature distribution, Joule effect, structural deformation, natural frequency, and reaction force, which characterize the microgripper performance. The material used in the analysis was Silicon. A thermoelastic model, that describes the behavior mechanical of the device, is developed. The device had an initial gap of 28 μm and a final gap of ~ 4 μm, the force of subjection in grippers is 0.4 μN.

In this semi-spherical meter, a single detector is used to realize all measurements, which is located on the extreme of a rectangular ring (assumed as joined two mobile branches in order to compensate the weights), describing half-meridians from 0° up to 170°. The illumination source under test is located at the center of the mobile support, which can rotate 360° horizontally. The two combined movements allow us to obtain a semi-spherical geometry. The number of measurement points is determined by the two step-motors located under the mobile support of the luminary and on one of the two fixed arms, which support the mobile rectangular ring, respectively. The mechanical arrangement has the enough rigidity to support the precision required for the acquisition stage, based on a dsPIC. The main advantages of this arrange are: Its low costs (using recyclable materials only such as "electronic waste"), a reliable detection based on a single photo-detector, with an integrated amplification stage, and the mechanical design. The received power by the detector is useful to obtain the irradiance profile of the lighting sources under test. The semi-spherical geometry of the meter makes it useful for the analysis of directive and non directive sources, in accordance with the angle described by the mobile ring. In this work, special attention is given to LED lamps due to its impact in several sceneries of the daily life. A comparison between the irradiance patterns of two LED lamps is also given.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

In this paper, the optimization of a chevron V-shape microactuator device to achieve higher actuation force and displacement is discussed. General information approach that includes the description of a physical model used in order to analyze the device behavior and the optimization of its design is considered. Shuttle and beams of a conventional electrothermal chevron V-shape microactuator device were modified. Pneumatic microactuators were implemented along the shuttle. The device was designed with silicon material. The device was characterized through a coupled electro-thermomechanical analysis using ANSYS-Workbench. Compared to the conventional chevron V-shape microactuator, the output work of the improved microactuator shows an increment of about 50% in displacement and 40% in actuation force, at the same maximum temperature source applied. A microgripper is developed are immediate application.