Torsional Suspension Research Articles

Two-axis MEMS angular rate sensor with magnetoelectric feedback torques in excitation and measurement channels

The design of a two-axis micromechanical angular rate sensor based on a vibrating gyroscope of R-R type is presented in this paper. The gyroscope is built with the use of “sandwich” scheme, which uses the magnetoelectric exciter of torsional oscillations of a silicon sensitive element, two feedback loops on measurement channels consisting of capacitive pickoffs, amplifiers and magnetoelectric torquers (MT). Design features of the device provide its operability in gas-filled chamber at atmospheric pressure. Digital systems designed for the resonance tuning of the device and the maintenance of constant amplitude of angular rate of pendulum oscillations are described. The systems compensating the device zero bias and generating the output signals based on the microcontroller are also considered. The reasons for occurrence of gyroscope zero bias, connected with manufacturing defects of torsional pendulum elastic suspension and magnetic systems, are analyzed, and recommendations are given for their compensation by using such procedures as adjusting magnetic system of the exciter of torsional oscillations, modifying the elastic elements and introducing a compensating signal in a feedback loop. The results of calculating an elastic micromechanical system, modeling a gyroscope motion are presented in the paper at various ways of forming a feedback loop, as well as results from experimental research of the micromechanical angular rate sensor under development.

Some calculations of [formula omitted] for low [formula omitted

In a previous paper, the authors gave the finest functorial decomposition of the loop suspension of a p -torsion suspension. In order to determine the decomposition, one must know the maximum projective submodule of Lie ( n ) , which we label Lie max ( n ) . The purpose of this paper is to give some sample calculations of Lie max ( n ) for low n when p = 2 .

105 風乱と高バンド幅化に対するサスペンションの設計法

This paper reports on the resonance controls of a suspension used for a magnetic Hard-Disk Drive (HDD). First, the control method of torsion mode gain, induced by shaking, is described. Secondly, the control method of torsion mode suspension flutter, induced by air turbulence, is described. The mechanism of first torsion suspension flutter was investigated, and the evaluation method by calculations was proposed. Finally, a new type of suspension using two separate parts for the loadbeam was designed. The evaluation results of the actual samples agreed with the calculated values. The new design achieved considerably high performance of suspension flutter characteristics with very high resonance frequency of first torsion mode.

A high-sensitivity z-axis capacitive silicon microaccelerometer with a torsional suspension

This paper presents a new z-axis high-sensitivity silicon-micromachined capacitive accelerometer fabricated using a three-mask dissolved-wafer process (DWP). It employs capacitive sensing using overlap-area variations between comb electrodes and a torsional suspension system to provide high sensitivity without compromising bandwidth, full-scale range, or the pull-in voltage ceiling. Excellent electrical sensitivity is obtained by using high-aspect-ratio comb fingers with narrow air gaps of 2 /spl mu/m and a large overlap area of 12 /spl mu/m /spl times/300 /spl mu/m. Torsional suspension beams 150 /spl mu/m long with a cross-sectional area of 12 /spl mu/m /spl times/3 /spl mu/m are used to improve the mechanical gain. Simulations of the capacitance between sense fingers show a highly linear region over a wide 14-/spl mu/m tip deflection range. Accelerometers were fabricated and yielded sensitivities of 263-300 mV/g, a nonlinearity less than 0.2% over a range of -4 to +3 g, a full-scale range of -4 to +6 g, and pull-in voltages greater than 8 V. A 3 dB cutoff frequency of 35 Hz was measured in air. The calculated thermomechanical noise in the sensor is 0.28 mg over this bandwidth.

Stress-dependent damping in Cu [sbnd]Be torsion and flexure suspensions at stresses up to 1.1 GPa

Stress-dependent damping in Cu Be torsion and flexure suspensions has been measured at stresses up to 1.1 GPa, 95% of the yield stress. The modulus defects of Cu Be increases from 4.3 × 10 −5 to only 6 × 10 −6 in this range. A much larger additional damping, orginating at the clamping interface between the suspension and its support, was identified and eliminated.

The Effect of Chassis Torsional Stiffness and Suspension Roll Stiffness Distribution on Truck Handling

In the design of a new vehicle, optimization of stability and handling is in conflict with optimization of ride and vibration, and with durability of suspension and structural components The purpose of this study, in which vehicle handling was the focus of attention, was not to provide specific vehicle recommendations but rather to reveal the main trends used to assist the design process. The maximum speed of a 20 m long 3.5 m offset lane-change manoeuvre to avoid an obstacle was investigated, this being defined as the velocity of the vehicle when it could not follow the marked traffic lane or lifted a wheel.

Errors of gyroscopic instruments with torsional suspension of the sensitive element

Errors of gyroscopic instruments with torsional suspension of the sensitive element

Meissner effect torsion suspension

The first tests of a Meissner effect torsion suspension consisting of a hollow superconducting sphere suspended above a circular superconducting coil have yielded torsion coefficients comparable to or softer than those of 25 μm (0.001 in.) fibers of the type commonly used in gravitation experiments. Data show anomalous behavior which can be attributed to trapped flux. This has at least two effects: it stiffens the torsional restoring torque and it causes a torque about an axis which is oblique to the desired vertical axis. External Helmholz coils modify this by providing compensation for axial asymmetry to reduce the torsion coefficient by a factor of 5 in these experiments. Methods to separate and evaluate the various effects are presented. With improved leveling and field-free cool down in future experiments it is likely that much larger torsion reduction factors will be reached.

Fluctuations in a non-Maxwellian gas

The velocity distribution of a noble gas in a very strong magnetic field has been shown to be non-Maxwellian. It is assumed here that a torsional suspension is immersed in such a gas. The average potential and kinetic energies of the resultant fluctuation are computed using Langevin’s method. They are found to be (kT/2), notwithstanding the reduced population of molecules at higher speeds.

Determination of the frequencies of precessional vibrations of a double-rotor gyroscopic device on a torsional suspension

Determination of the frequencies of precessional vibrations of a double-rotor gyroscopic device on a torsional suspension

Device for producing a small controlled rotation

A device is described for producing small (ca. 1 mu rad) rigid body rotations of optical elements about an accurately known axis. The usual difficulties of backlash and hysteresis associated with a rotary stage are avoided by mounting the stage on an elastic torsion suspension. Rotation of the stage is accomplished by applying an accurately known torque to the stage by controlled deformation of extensional springs.

The development of a torsional suspension molecular vacuum gauge

The design, development and calibration of torsional suspension molecular vane gauge is described. The limiting effect of the torsional suspension upon the operating range of the gauge is investigated. Tests to increase the operating frequency if the vane in order that the gauge may be driven electronically are described. The sensitivity of the gauge is compared with previous sensitivities of gauges having similar mechanical construction.

A new magnetometer for small scale magnetic studies

A new magnetometer is described for measurement of the permanent magnetization of small particles of magnetic material and for the examination of magnetized surfaces. It has been developed for investigations in rock magnetism involving small grains of natural magnetic minerals, both after separation from the parent rock and while still in place in a rock surface. The detector is a small spherical magnet on one end of a fine, horizontal glass arm, the other end of which is attached to a vertical torsional suspension. A torque is produced about the suspension axis when the magnet is in a horizontal magnetic field with a vertical gradient, such as is produced by a magnetized particle in the vicinity of the magnet. Particle magnetizations of the order of 10-9 G cm3 (10-12 A m2) may be measured, and, under appropriate conditions, estimates of low field susceptibility of the particles may also be made.

A method of measuring dielectric losses at very low frequencies

The paper describes a method for measuring the dielectric losses in solids, using the oscillations of the sample on a torsion suspension in an electric field. The necessary relations are derived and the method is used in measuring the dielectric losses of vulcanized caoutchouc.

Production of flattened sheet for the torsion suspension of the ?Zaporozhets? automobile

Production of flattened sheet for the torsion suspension of the ?Zaporozhets? automobile

High-precision moving-coil laboratory instruments with torsion suspensions

High-precision moving-coil laboratory instruments with torsion suspensions

Basic trends of work in the ?Vibrator? plant on electrical measuring instruments with torsion suspensions

Basic trends of work in the ?Vibrator? plant on electrical measuring instruments with torsion suspensions

Thermal instruments on torsion suspensions

Thermal instruments on torsion suspensions

The use of torsion suspensions in vibration- and shockproof instruments

1. A shockproof and vibrationproof circular-dial rack-mounted instrument with torsion suspensions can be designed for a sufficiently wide frequency range. 2. In producing such an instrument it is necessary to aim at a minimum weight for the moving part and maximum tensioning of the suspensions. Moreover, the natural frequencies of the instrument's components and units should be, as far as possible, outside the range of the vibration frequencies which may be encountered in the instrument's application. 3. The displacement of the instrument's moving part must be limited, and the limiter gaps should be made smaller than the effective gaps between any other components of the instrument and its moving parts under vibration conditions, taking into consideration the contraction of gaps under vibrations and the possibly accompanying resonance effects. 4. It is recommended that the limiter gaps be filled with polysiloxen liquid of medium viscosity, and all the surfaces limiting the spreading of polysiloxen should be carefully treated with a substance which prevents the wetting of the surface by the liquid. 5. The displacement of the damping springs in the direction away from the moving system should also be limited. Moreover, the gaps in these limiters should be smaller than the corresponding gaps in the limiters of the moving system's displacement in the same direction. 6. All these provisions are additional to and do not replace the measures normally taken in designing shockproof instruments for the purpose of damping the whole instrument or its measuring mechanism.

Physicomechanical properties of torsion suspensions for electrical measuring instruments

At present the Soviet instrument designers have an extensive available range of torsion suspensions for measuring instruments made according to GOST 9444-60 of four materials with any required values of restoring torque, in the range of 0.01 to 20 mg-wt·cm/90° and a length of 100 mm.