This paper presents a novel capacitive microelectromechanical systems (MEMS) accelerometer with slanted supporting beams and all-silicon sandwich structure. Its sensing mechanism is quite similar to an ordinary sandwich-type MEMS accelerometer, except that its proof mass is suspended by a beam parallel to the {111} plane of a (100) silicon wafer. In this way, each sensing element can detect accelerations in two orthogonal directions. Four of these sensing elements could work together and constitute a 3-axis micro-accelerometer by using a simple planar assembly process. This design avoids the traditional 3-axis accelerometer’ disadvantage of possible placement inaccuracy when assembling on three different planes and largely reduces the package volume. The slanted-beam accelerometer’s performance was modeled and analyzed by using both analytical calculations and finite element method (FEM) simulations. A prototype of one sensing element was fabricated and tested. Measured results show that this accelerometer has a good bias stability 76.8 ppm (1σ, tested immediately after power on), two directional sensitivities (sensitivity angle α = 45.4°) and low nonlinearity (<0.5%) over a sensing range up to ±50 g, which demonstrates a great opportunity for future high-precision three-axis inertial measurement.

This paper on the reports design, fabrication and position monitoring of a micro electromagnetic linear actuator. The actuator consists of stator, slider, guide, sensors and affiliated jigs. Actuation is achieved through ampere force between two phase micro-coils (copper) on the stator and permanent magnets (thick NdFeB film) on the slider. During the slider’s movement in the guide slot, tunnelling magneto-resistance (TMR) sensors are utilized to sense the magnetic field to realize position monitoring. TMR is chosen because it owns advantages of small size, large sensitivity and easy integration with micro devices. Purpose of this research is to report the micro fabrication of thick magnet films and testify the possibility of using TMR as position monitoring sensors. Actuators are fabricated by micro-electro-mechanical system process (stator and guide) and precise machining (slider and jigs). Surface magnetic field generated by the slider, driving characteristics of the actuator as well as the position monitoring capabilities of TMR elements are simulated and experimented, respectively. The slider attains 60 mm s−1 speed by sinusoidal input signal at 300 Hz frequency and 0.2 A current magnitude. Actuation bandwidth is between 300 Hz and 500 Hz at open loop condition. The maximum position monitoring error in present work is 2.2% with 101 μm value for 4.5 mm stroke.

This paper presents the design, fabrication and characterization of a novel micro electromagnetic linear actuator, which exhibits two highlights: slider self-alignment and self-attachment capability. Such characters are realized by deliberately utilizing the attractive force between the permanent magnets (Nd2Fe14B) of the slider and nickel ferromagnetic cores embedded in the stator. Actuation is achieved via thrust from both meander micro copper coils and nickel ferromagnetic cores in the stator to the permanent magnets of the slider. The actuator is fabricated by the micro machining process. The surface magnetic property of the slider is simulated and experimentally measured. The eccentric experiment is conducted to evaluate the attraction force between the slider and stator, which proves its self-attachment characteristics. The device is actuated by two-phase sinusoidal currents with a 0.5 A amplitude under an open-loop condition. The slider demonstrates self-alignment movements before moving forward when misalignment occurs. The actuation experimental results show that the average velocity of the slider reaches 4 mm s–1 and 12 mm s–1 at 10 Hz and 30 Hz, respectively. Further increasing the input frequency to 50 Hz leads to the unsteady actuation state, indicating the actuator bandwidth is less than 50 Hz under an open-loop condition.

This paper introduces the design, fabrication and characterization of a micro electromagnetic linear actuator integrated with magnetic guide. The actuator consists of a slider, a stator and a magnetic guide. A magnetic guide is used to replace the mechanical rail of conventional linear actuator to ensure the linear motion and to avoid friction. The purpose of this paper is to study the influence of magnetic guide on the dynamic characteristics of electromagnetic linear actuator and measuring techniques for micro-actuators. To test the resistance to motion and output thrust force of the actuator, a cantilever type force sensor is proposed, which can measure the small force in ~mN order, and the measurement error is less than 3%. Using this sensor, the output thrust measured is higher than 10mN when 1A current is applied, and the friction force of the actuator measured is about 7.73mN. Two-phase square wave and sine wave current are used to drive the actuator, the minimum driving current and frequency of the actuator are less than 0.1A and 1Hz respectively. The actuator attains a maximum stable moving speed of 0.15m/s with the input signal frequency of below 250Hz. In addition, the anti-interference capability of the actuator is evaluated through simulations and experiments. These results show that the actuator can bear an interference 45 times its own gravity in the directions that are perpendicular to the moving freedom, and can adjust the direction of motion automatically when the rotation angle in three orthogonal directions is less than 6 °.