Patriot Sensors & Controls, Inc.

Magellan Dis, Inc.

Magnetek Controls

Magnetek, Inc.

Patriot Sensors & Control Corporation

John D Begin

Richard D Koski

Larry E Spencer

Ka C Cheok

James Webb

Jody Page

Giancarlo Castillo

A vehicle navigation system includes a vehicle displacement sensor comprising a wireless transmitter generating a signal indicating rotational displacement of a vehicle component. A complementary wireless transmitter receives the signal from the transmitter. A computer calculates vehicle speed or displacement based upon the rotational speed or displacement of the vehicle component. In a preferred embodiment, the transmitter is secured to a wheel of the vehicle and generates an RF signal upon each revolution of the wheel.

Vehicle speed sensor for navigation system

A method for calibrating an orthogonal sensor suite includes the steps of imparting on the sensor suite a series of known accelerations at orientations known relative to each other, while recording readings from the sensors from each acceleration at each orientation. This data is used to create a transformation matrix which removes offsets from each sensor and removes any cross-coupling of the sensors.

Calibration of orthogonal sensor suite

A navigation system includes a multi-axis accelerometer which can be installed in the vehicle in any unknown orientation. The orientation of the axes of the accelerometer is automatically determined by the navigation system. The signals from the accelerometer are then used to propagate the position of the vehicle.

Calibration of multi-axis accelerometer in vehicle navigation system

A magnetostrictive wire waveguide type position measuring system wherein the wire waveguide is mounted within a small diameter brass tube which, in turn, is mounted by way of resilient suspension components within a rigid outer tube affixed to a position reference frame. The suspension components isolate the waveguide from relatively high frequency shock inputs characteristic of rough environment applications. The position signal is derived from output signal quantities generated by the propagation times of sonic disturbances from a first reference magnet held in a fixed position relative to the outer housing and a second user magnet which moves relative to the outer housing with the element or quantity being monitored. To compensate for longitudinal movement of the waveguide within the floating suspension system, a computer calculates a variable time delay related to the difference between a constant time quantity and the propagation time of the reference magnet impulse and adds this time delay to the user magnet propagation time. The waveguide terminal ends are gradually reconfigured from round to flat, rectangular sections and sandwiched between acoustic dampening pads to reduce or eliminate sonic reflections. A flexible film piezoelectric pickup is disclosed.

Position measurement apparatus using wire waveguide in shock resistant suspension

A method and apparatus for determining the position of a movable object along a magnetostrictive wire having first and second opposed ends. A first electrical excitation pulse is applied to a two-wire circuit including the magnetostrictive wire and propagates along the wire to the position of a movable magnet surrounding the wire. The magnet generates oppositely directed first and second torsional waves in the wire. One torsional wave propagates along the wire to a reflective termination at the second end of the wire and is reflected back toward the magnet where it interacts with the magnetic field of the magnet to induce a return electrical pulse in the two-wire circuit. The position of the magnet along the wire is determined from the time differential between the first and second electrical pulses in the two-wire circuit. In another embodiment, a second magnet is mounted in a fixed position about the wire and generates oppositely directed third and fourth torsional waves in response to the first excitation signal, one of which propagates along the wire toward the first magnet which induces an electromagnetic force in the two-wire circuit. A torsional wave generated by the first movable magnet in response to the excitation signal induces another electromotive force in the two-wire circuit when it propagates to the second magnet.

Pickupless magnetostrictive position measurement apparatus

A magnetostrictive waveguide position measuring apparatus includes a waveguide extending between opposed anchored ends. A magnet is displaceable along the waveguide and generates torsional strain in the waveguide in response to an electrical excitation signal transmitted along the waveguide. A piezoelectric film element is coupled to the waveguide to sense the torsional strain signal on the waveguide. A signal processor determines the relative elapsed time between the excitation signal and the output signal of the piezoelectric film element to determine the position of the magnet along the waveguide. The piezoelectric film element is coupled to the waveguide along an axis transverse to the axis of stretch of the element. Alternately, a differential piezoelectric film element formed of two piezoelectric elements contacts a waveguide, with the two elements connected in differential parallel or series configuration and in or out of phase to double the output current or the output voltage. The output of the differential piezoelectric elements are connected to an amplifier in either charge or voltage mode for noise, EMI and transient signal suppression.

Magnetostrictive waveguide position measurement apparatus using

A magnetostrictive wire waveguide type position measuring system wherein the wire waveguide is mounted within a small diameter brass tube which, in turn, is mounted by way of resilient suspension components within a rigid outer tube affixed to a position reference frame. The suspension system prevents relatively high frequency shock inputs characteristic of rough environment applications from reaching the waveguide. The position signal is derived from output signal quantities generated by the propagation times of sonic disturbances from a first reference magnet held in a fixed position relative to the outer housing and a second user magnet which moves relative to the outer housing with the element or quantity being monitored. To compensate for longitudinal movement of the waveguide within the floating suspension system and to afford a time interval for further signal compensation purposes, a computer calculates a variable time delay related to the difference between a constant and the propagation time of the reference magnet impulse and adds this variable delay to the user magnet propagation time. Position is determined as a function of the time interval between and original excitation signal and the propagation variably delayed user magnet impulse.

Position measurement apparatus and method of using same with sonic pulse

Position measurement apparatus using wire waveguide in shock resistant

A magnetostrictive waveguide type position measuring system wherein the wire waveguide is mounted within a small diameter brass tube which, in turn, is mounted by way of resilient suspension components within a rigid outer tube affixed to a position reference frame. The resilient components isolate the waveguide from relatively high frequency shock inputs characteristic of rough environment applications. The waveguide is made of rolled and drawn wire with a round section, but the terminal ends are gradually reconfigured from round to flat, rectangular sections and are sandwiched between acoustic dampening pads to reduce or eliminate sonic reflections.

Magnetostrictive position measurement apparatus with anti-reflection

In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot end termination as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made by measuring the wire resistance and calculating a compensation from the resistance. The probe is excited by an electrical pulse having a known current. The voltage across the wire is measured at a time when the current has stabilized to a precise value, and resistance is determined from the current and voltage.

Method and apparatus for temperature compensation of magnetostrictive

In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made based on the property of the total propagation time along the wire length being a unique function of temperature and calibrating the probe at different temperatures to yield either equations or look up tables of true positions as functions of the total propagation time and the position detection parameter. By mapping wire characteristics at a plurality of magnet positions and temperatures to construct look up tables, wire nonlinearities as well as thermal effects can be compensated for.

Temperature compensation for magnetostrictive position detector

A position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet movable along the probe uses the sonic pulse propagation time from the magnet to the head as one parameter and the time from the magnet to the foot and reflected back to the head as another parameter for determining the magnet position. The sum of the propagation times is a constant which is used as a reference value. Upon receipt of the first two pulses the propagation times are summed and compared to the reference value, and the data is accepted if the sum is within a prescribed window around the reference value. When noise occurs, it creates a false measure of propagation time so that the sum of the propagation times is no longer equal to the reference value and the data is rejected.

Method of noise rejection in a magnetostrictive position detector

The present invention is a combined magnetostrictive linear displacement detector and plural location temperature detector. The combined apparatus produces a composite signal for transmission on a 2 wire transmission line. The resistances of the temperature sensitive resistors as well as two reference resistors are measured in a predetermined sequence. The linear displacement is measured by the length of time required for a torsional strain to travel along the magnetostrictive wire to the position of the magnet. A pulse generator generates a predetermined number of pulses for each resistance measurement having pulse period corresponding to the measured resistance, with the minimum such pulse period preferably being greater than twice the maximum time required for a torsional strain to propagate the length of the magnetostrictive wire. An electrical signal is supplied to the transmission line when either said pulse generator generates a pulse or the induced electrical signal is detected. The time between the pairs of pulses indicates the linear displacement fixed by the magnet. The time between pulse pairs is a measure of one of the resistances. The combined apparatus of the present invention also periodically degausses the magneteostrictive wire at a time when no displacement measurement is taking place.

Magnetostrictive linear position detector with temperature sensors

An adaptive time period measurement technique which provides full speed for every measurement period with increased resolution afforded from repeated measurements. The time measure is produced by adaptively filtering a number of prior time measures. Each measurement includes a count and a fractional part from a controlled variable delay interposed in the measurement system. This variable delay is controlled over a number of measurements to cover the entire range of one clock cycle, preferably in accordance with a reversed binary progression algorithm. The adaptive filtering is preferably a self-modifying, classic low pass filter with a roll off which depends on the rate of change and direction of change of the measurerd time period. Thus the present invention provides all the resolution feasible based upon the rate of change of the measured quantity.

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Troy, MI, United States of America

John D Begin