Measurement Of Angular Acceleration Research Articles

Use of a piezoelectric polymer for angular position and acceleration measurement

An angular and acceleration measurement system using the piezoelectric polymer poly (vinylidene fluoride) is described, furthermore a compensation of the polymer's pyroelectric effects has been achieved. The advantages of this sensor are that there are no moving parts and that it has a very low cost compared with other sensors. The measured sensitivity is 3.7 mV rad-1 s2.

加速度計を用いたスポーツにおける角速度・角加速度計測

加速度計を用いたスポーツにおける角速度・角加速度計測

Improvement of linearity in distance measurement system using guided-wave type optical modulators : 11th Meeting on Lightwave Sensing Technology. Japanese Society of Lightwave Sensing Technology, Japan Society of Applied Physics

The paper deals with the development and realization of a diffraction grating interferometer for the accurate dynamic measurement of angular acceleration, angular velocity and rotation angle. Investigations carried out to compare the metrological characteristics of lithographically and holographically manufactured diffraction gratings revealed that the latter allow two-beam interferometers to be implemented in a way similar to that widely used to accurately measure translational motion quantities (e.g. using a Michelson interferometer with retroreflector). A special grating interferometer using a holographically manufactured sine-phase grating on the lateral surface of a circular disk is described in detail and results of its applications are given.

Angular acceleration measurements with the PASCO ME-9279

Angular acceleration measurements with the PASCO ME-9279

Measuring simultaneously translational and angular acceleration with the new translational-angular-piezobeam (TAP) system

The new translational/angular accelerometer presented in this paper consists of a pair of identical piezoelectric cantilever beams inside a metal housing. Integrated hybrid charge amplifiers convert the piezoelectric charge signals to high level, low impedance voltages. The sensor is easily mounted on the surface of the structure under test by fixing it with wax or glue. It allows the simultaneous measurement of translational and angular acceleration. An example of an estimation of the frequency response function of a free-free beam is presented.

Digital measurement of angular velocity for speed control

A digital method to measure angular velocity for machine control applications is described. The method uses a phase-locked loop to multiply the frequency and reject the jitter. The process for measurement is completed in a very short time, providing not only quick readouts, but also information on transient velocity. Since the sampling intervals are fixed, measurement of angular acceleration can be obtained almost immediately.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Model Correcting Attitude and Position Estimation Filters

The paper discusses the structure of filters which process angular and linear acceleration, velocity and position measurements to obtain estimates of attitude and position of a vehicle with respect to some external object moving with constant velocity. Especially these structures can be useful for combined attitude and tracking filters with strapdown sensors and microprocessors.

Composition, operating principle, and metrological characteristics of the state standard of constant angular acceleration unit

The working facilities for angular acceleration measurement, angular accelerometers (AA), are being used more and more extensively in inertial navigation and control and telemetry systems, in tool construction, in transport, in checking the precision drivers of antennas, shafts, turbines, in automatic control systems, etc., because of their simplicity of construction, the fabrication technology, the high dynamic properties, the capacity for overloads, and their reliability under utilization.

Closure to “Discussion of ‘Measurement of Angular Acceleration of a Rigid Body Using Linear Accelerometers’” (1976, ASME J. Appl. Mech., 43, pp. 377–378)

Closure to “Discussion of ‘Measurement of Angular Acceleration of a Rigid Body Using Linear Accelerometers’” (1976, ASME J. Appl. Mech., 43, pp. 377–378)

A new digital instrument for measuring angular velocity and acceleration

A new approach to the digital measurement of angular velocity and acceleration is discussed. The proposed instruments provide a very high precision and resolution in measurement. The measurements can be made in a very short time, which may be regarded as almost instantaneous for many practical applications.

Digital Instrumentation for Angular Velocity and Acceleration

An instrument is described for the measurement of angular velocity and angular acceleration of a rotating shaft, based upon an optical angular transducer and an associated operational digital (pulse rate) system. The angular transducer produces a pulse rate directly proportional to the instantaneous angular velocity and this quantity and its rate of change are processed by the pulse rate system and presented as parallel binary-coded decimal representations driving in-line digital displays. The operational digital system comprises essentially an electronic register controlling a variable rate pulse generator that tracks the input pulse rate in a frequency lock loop. Changes of loop frequency are brought about by changing the register contents by positive or negative correction pulses, and the rate at which these are supplied provides an accurate measure of acceleration or deceleration, respectively, provided that the loop is locked on and hence follows the changes of input pulse rate accompanying changes of angular velocity. The error correction pulse rate may be measured in a second frequency lock loop and the registers in the two loops used to control digital in-line decimal displays of angular velocity and acceleration, of ranges up to 10 000 r/min (±1 r/min) and 1000 r/min/s (±1 percent), respectively.

Jet damping of a solid rocket - theory and flight results

The angular motion of a spin stabilized solid rocket is computed, considering the effect of jet damping about axes normal to the spin axis. The approximate formula used is chosen for computational accuracy and to fit the rocket geometry. Results are compared with measurements of body angular acceleration made during the rocket's flight in space. The comparison indicates that the jet damping is a very strong effect in this case, and that the approximate formula gives adequate accuracy for computing the reduction in conical precession motion due to jet damping. It is probable that the same formula can be used to estimate jet damping for other solid rockets. I. Introduction T HE term jet damping refers to the change in the angular rates of a thrusting rocket due to the torques exerted by the gases flowing out the nozzle. The jet damping effect is especially important in spin stabilized rockets where it acts to reduce the amplitude of the conical free precession motion and, therefore, to reduce the motion to a steady spin. It is important to know what the cone angle is at staging, as this strongly influences the attitude error of the next stage. In rockets operating in air, jet damping is usually second in importance to aerodynamic moments. In vacuum, however, the jet damping can be the most important torque acting on the rocket. Several simplified theories have been proposed to give estimates of the rate of damping for a particular rocket.15 In general, these theories use one-dimensional gas flow in the rocket and characterize the thrust chamber and nozzle by certain approximate dimensions. Proper verification of these approximate theories has been difficult to obtain because of the lack of experimental data on the attitude of a spinning rocket in vacuum flight. In the present paper, a formula for pitch jet damping is derived from the general rocket equations in a body-fixed coordinate system assuming one-dimensional flow. The formula is selected to use quantities that are known accurately and to be compatible with the geometry of the rocket considered. The formula, a modification of the one presented in Ref. 4, is evaluated to give the predicted rate of cone angle damping for a particular frequently used spin-stabilized rocket, the Allegany Ballistics Laboratory! X-248 with a satellite payload. The resulting prediction of jet damping is then compared with measurements of the angular motion made in actual flight.

The Two-Phase Accelerometer

A direct measurement of shaft angular acceleration may be made with a conventional drag cup tachometer operated as an accelerometer. In this operating mode the tachometer is supplied with direct current and provides a direct voltage proportional to acceleration. This paper presents the theory of operation, experimental accelerometer characteristics of a commercial tachometer, and a number of interesting applications of this novel device.

The two-phase accelerometer

A direct measurement of shaft angular acceleration may be made with a conventional drag cup tachometer operated as an accelerometer. In this operating mode the tachometer is supplied with direct current and provides a direct voltage proportional to acceleration. This paper presents the theory of operation, experimental accelerometer characteristics of a commercial tachometer, and a number of interesting applications of this novel device.

A Pick-Up for the Measurement of Quasi-Static Angular Acceleration

Design parameters for an angular accelerometer are developed. The accelerometer incorporates an electrical sensing element which may be energized by dry cell batteries and whose output may be connected directly to a recording galvanometer.