Abstract: A sensor is positioned to sense the magnetic field strength of a magnet associated with a rotating body. The sensor produces a signal having a sinusoidal output as the magnet rotates with the rotating body. A controller takes a derivative of the output and calculates the rotational velocity of the rotational body as a function of the derivative.

Abstract: A method of measuring the period of a vehicle speed signal is disclosed that includes the steps of accumulating predetermined time interval increments between first and second rising edges of the signal, calculating a remainder time interval upon detection of the second edge of the signal and adding the remainder to the accumulated increments value to obtain the period, and calculating an average period from a plurality of consecutive period measurements. If the accumulated value exceeds a predetermined maximum value before the second edge occurs, the maximum value is used in calculating the average.

Abstract: A method and apparatus for monitoring the operation of vehicle brakes on a vehicle equipped with an electronic braking system as is commonly used to provide traction control (TC) and/or an anti-lock braking system (ABS). The speed at which a first wheel located on a first side of a vehicle rotates in relation to the speed at which a second wheel located on a second side of the vehicle rotates during particular braking events is examined. For each wheel, any difference or "error" in the rotation speed during the select braking events relative to the other side wheel is accumulated or integrated over a select duration until a threshold difference value is reached which indicates a malfunction at the subject wheel end. The accumulated difference is periodically adjusted to account for normal or acceptable levels of wheel speed variation.

Abstract: A circuit for generating a speed value corresponding to a rotational frequency of a rotating shaft. A digital tachometer circuit has a tachometer circuit and a copy/hold circuit. The tachometer circuit maintains an intermediate speed value which is incremented by a gain constant as the rotational frequency increases and is decremented as the rotational frequency decreases. The copy/hold circuit samples the intermediate speed value at selected intervals, thus generating the speed value. The speed value is displayed to a user and represents the vehicle's speed.

Abstract: A method for calculating an amount and determining a position of an eccentric mass existing in a rotary head apparatus of a fixed shaft type, and to an apparatus for calculating and determining the same is disclosed. The method for calculating an amount and determining a position of the eccentric mass of the rotary head apparatus of the fixed shaft type and the apparatus for calculating and determining the same, are very accurate and credible. Accordingly, the rotational vibration of the head apparatus can be largely reduced through a balancing utilizing the eccentric mass calculated by and determined by the above-mentioned method and apparatus.

Abstract: To achieve both accuracy in correcting sensing error caused by nonstandard factors of a pulse signal generated by rotation of a rotor to be measured and reduction in cost of an apparatus for doing the same, each passage of rotor sensors which rotate integrally with vehicle tires are sensed to produce pulse signals. The pulse signal periods are sequentially integrated every pulse signal train consisting of multiple pulse signals. When all of the pulse signal periods of the pulse signal train are integrated, the integrated value is stored in memory. The memory always stores the integrated values of the newest one rotation of the rotor to be measured. The pulse signal periods are averaged from the sum of the integrated values. With such a construction, the average of the pulse signal periods can be obtained as a learning reference value in the correction without storing all of the pulse signal periods of one rotation, thereby realizing both correction accuracy and cost reduction.

Abstract: A dithered Coriolis acceleration sensor system has a proof mass that is free of feedback in the accelerometer servo loop at the dither frequency by totally notching out all feedback torque at this frequency. The proof mass relative motion is then a direct measure of the rate because there is no feedback torque to alter the proof mass response to the acceleration. The feedback modulation system according to the invention captures the Coriolis-sensor output such that the phase and gain of the signal generated from the sensor are of no concern in maintaining good scale factor.

Abstract: The present invention provides a system which calculates vehicle speeds from distance pulses utilizing vehicle acceleration. More particularly, the present invention calculates vehicle speed through a system comprising a speed input task and a speed output task. The speed input task generates a speed value and an acceleration value from a pulse train delivered by a distance sensor or electronic transmission. The acceleration, deceleration or steady state of the motor vehicle is determined in the input task through use of the distance sensor tolerance. The output task drives the speedometer according to the new speed value from the input task if a new speed value has been generated since the last execution of the output task. If no new speed value has been generated since the last execution of the output task, the output task drives the speedometer according to the acceleration value. Thus, the output task is executed periodically regardless of the sequence of pulses received in the input task.

Abstract: Method of measuring the yaw velocity of a vehicle. An estimate of the yaw velocity is made by either a gyrometer or a steering angle sensor. This estimate is selectively readjusted when a fixed obstacle is sensed using periodic updates of the longitudinal speed of the vehicle, the distance from the fixed obstacle and the relative transverse speed of the obstacle.