Gm Global Technolgoy Operations, Inc.

Delco Electronics Corporation

Kamal N Majeed

John F Hoying

James J Kowalik

Albert Victor Fratini, Jr

Scott A Stacey

Reed D Hanson

Donald E Schenk

Richard Edward Longhouse

Eric Lee Jensen

Aleksander Boguslaw Hac

Hsien Heng Chen

Edward John Bedner

Mark Olen Bodie

Steven L Tracht

Bruce A Heaston

Eldon Gerrald Leaphart

Joan B Arwine

Joachim Busshardt

Richard Charles Swortzel

Marc J Georgin

Steven P Sammut

James W Hauser

Jay R Varner

Mark R De Poyster

John J Westerkamp

A brake system control method, comprising the steps of: determining a maximum acceleration of a vehicle on a high coefficient of adhesion road surface; measuring an acceleration of the vehicle; determining a ratio between the measured acceleration of the vehicle and the maximum acceleration of the vehicle on the high coefficient of adhesion road surface; responsive to the ratio, determining a signal indicative of present coefficient of adhesion; determining a brake actuator command responsive to the signal; and providing the brake actuator command to a brake actuator, wherein an accurate estimation of coefficient of friction between the vehicle wheels and the road surface is used in the brake system control.

Brake system control method responsive to measured vehicle acceleration

A chassis system control method comprising the steps of measuring rotational speed of a plurality of vehicle wheels; estimating, responsive to each wheel rotational velocity, a relative velocity between the wheel and a corresponding corner of a vehicle body; determining a chassis system control command responsive to the estimations; and applying the chassis system control command to control the chassis system responsive to the estimations, wherein need for body to wheel relative position and/or relative velocity sensors is eliminated.

Chassis control system for controlling a vehicle chassis system based on

In a vehicle with a first set of first and second wheels coupled to an electric drive system capable of providing regenerative braking and a second set of third and fourth wheels, wherein the vehicle dynamically adjusts a brake proportioning between the first and second sets responsive to a determined wheel speed difference between the first and second sets, the improvement comprising a regenerative braking control method according to the steps of: measuring first, second, third and fourth speeds of the first, second, third and fourth wheels; for each wheel of one of the first and second sets, determining a set-off value inversely relational to a commanded brake torque and a wheel deceleration; determining modified wheel speeds for each wheel of said one of the first and second sets responsive to the wheel speeds and the set-off values; and determining the wheel speed difference between the first and second sets responsive to the modified wheels speeds of said one of the first and second sets and the wheel speeds of the other of the first and second sets, wherein the dynamic adjusting of brake proportioning between the first and second sets increases brake torque load on the first and second wheels, increasing an amount of braking achieved regeneratively.

Regenerative braking method

A vehicle chassis system control according to the steps of: determining relative velocity between a corner of a vehicle body and a vehicle wheel responsive to a sensor signal from one of: (i) a relative position sensor mounted between the vehicle body corner and the vehicle wheel and (ii) a wheel rotational velocity sensor mounted to the wheel; estimating, responsive to the sensor signal, a body acceleration signal indicative of a vertical acceleration of the corner of the vehicle body; estimating, responsive to the sensor signal, a wheel acceleration signal indicative of a vertical acceleration of the vehicle wheel; estimating a dynamic normal force between the wheel and a road surface responsive to the estimated body and wheel accelerations; and providing the estimated normal dynamic force to a chassis system controller, wherein a chassis system actuator is controlled by a control command determined responsive to the estimated dynamic normal force.

Vehicle chassis control

A tire pressure monitor apparatus comprising a vehicle body, four vehicle wheels including tires disposed at four comers of the vehicle body, four position sensors, one mounted between each wheel and the corresponding corner of the vehicle body and a microprocessor controller, wherein the microprocessor controller receives signals from the four relative position sensors and determines, responsive thereto, for each tire, a signal indicative of a pressure of air within the tire.

Tire pressure monitor

A method of controlling a vehicle suspension system including a real time continuously variable damper comprising the steps of: (a) determining a present actuator command for controlling damping force of the damper; (b) comparing the present actuator command to a previous actuator command to determine a difference value of the actuator commands; (c) if the difference value is positive, limiting the difference value to a positive threshold; (d) if the difference value is negative, limiting the difference value to a negative threshold, wherein the negative threshold has a magnitude greater than a magnitude of the positive threshold; (e) determining an output actuator command responsive to the difference value; and (f) outputting the output actuator command to the damper to control damper force, wherein the limiting of the difference value to the positive threshold reduces suspension harshness and audible noise and wherein the limiting of the difference value to the negative threshold reduces suspension audible noise.

Continuously variable damping system

A vehicle has a real time suspension control which requires, as inputs, a set of absolute body modal velocity signals. Accurate estimates of these signals are derived from relative position sensors at the body suspension points by converting the relative vertical position signals from these sensors to relative body modal (e.g. heave, pitch and roll) velocity signals and passing each of these signals through a second order low pass filter including an additional phase inversion for compensation of the 180 degree filter phase lag. Thus, the necessity of absolute body accelerometers is eliminated, for a significant cost reduction. In a vehicle having significant front to rear flexing or flexing within the front or rear suspension that can affect the accuracy of the estimated absolute body roll velocity, the normal roll velocity transformation equation is modified to include only the front or the rear pair of relative velocity signals.

Vehicle chassis control system

A method of determining the trim set value of a vehicle body leveling system comprising the steps of: receiving a trim set command; responsive to the trim set command, retrieving a sensor output from a vehicle height sensor; determining a difference value between the sensor output and a predetermined offset, wherein the offset is indicative of an effect an average sized operator would have on the vehicle height as measured by said height sensor; and programming the difference value into a memory of a level control system, wherein the programmed value is the trim set value for the level control system.

Vehicle level control system

An active vibration control (AVC) system is disclosed for attenuating vibrational frequency components generated by an engine and transferred through an engine mounting unit to vibrate a motor vehicle body. The motor vehicle is characterized by sprung mass and unsprung mass natural resonant frequencies at which the body also vibrates when the vehicle is driven over an undulating road surface. The AVC system operates by generating input signals representing different vibrational frequency components generated by the engine based upon sensed changes in engine rotation. Each input signal is filtered by an adaptive filter to produce a respective output signal. The output signals are summed to produce a canceling signal for driving an inertial mass shaker mounted on the body. The shaker inversely vibrates the body with respect to the different vibrational frequency components transferred to the body from the engine. A vibration sensor mounted to the body proximate the shaker monitors body vibration and develops a representative error signal. Vibrational components associated with the sprung and unsprung mass natural resonant frequencies are substantially removed from the error signal using a dual notch filter. The filtered error signal is then used to adjust the filtering characteristics of the adaptive filter to minimize vibration of the body caused by the different vibrational frequency components transferred to the body from the engine.

Active vibration control system for attenuating engine generated

In a vehicle suspension control in which the output of a vehicle body mounted absolute vertical acceleration sensor is integrated to provide an absolute vertical velocity signal, the sensor output is high pass filtered to remove DC components but pass components in the frequency range 1-2 Hz. The filter comprises a second order digital all-pass filter embodied recursively on a 16 bit, fixed point, digital signal processor (DSP). A first stage normalized lattice two-pair network reduces to a unity gain stage; and a second stage single multiplier two-pair lattice network minimizes computational time. The 32 bit internal accumulators of the 16 bit DSP are used advantageously to prevent errors due to internal overflow of the recursive variable.

Real time suspension control with digital all-pass, high-pass filter

A full vehicle suspension control for a wheeled vehicle includes a suspension actuator and an absolute accelerometer at each corner of the vehicle body. The actuators are controlled in response to vehicle body pitch and roll velocity signals which are derived from nominally vertical acceleration signals from the accelerometers by first deriving vehicle body pitch and roll acceleration signals and then integrating these signals into vehicle body roll and pitch velocity signals. The process of converting the body corner acceleration signals to pitch and roll acceleration signals reduces any non-vertical error of the signals before integration to reduce saturation of the integrator.

Full vehicle suspension control with non-vertical acceleration correction

A full vehicle suspension control derives the vertical wheel and vertical body corner velocities at each corner of the vehicle body and derives therefrom a set of at least three body state velocity variables descriptive of vertical body motions and attitude. These body state velocity variables may be the body heave, roll and pitch velocities or a plurality of the vertical body corner velocities. The suspension control computes desired forces between each body corner and its corresponding wheel from a linear combination of the vertical wheel velocity of that wheel and the body state velocity variables and derives control signals from the desired forces and, in a semi-active system, the sign of demand power. The control signals are applied to vertical force actuators connected to exert vertical forces between the vehicle body and wheel at the vehicle body corners and capable of response at frequencies sufficient to control wheel as well as body vibrations in real time.

Full vehicle suspension control

A controlled suspension for a wheeled vehicle includes a damper between the vehicle body and wheel, the damper being switchable, at a frequency sufficient for the control of resonant wheel vibrations, between a first mode of operation characterized by a high damping force and a second mode of operation having a low damping force. A control repeatedly derives from sensed vehicle suspension related operating variables desired force to be applied between the body and wheel in order to produce a desired suspension behavior determines whether that force result in active or dissipative suspension power. The control further stores a threshold and controls the damper for each derivation so that (1) the damper operates in its second mode of operation when the desired force would produce active power, (2) the damper operates in its first mode of operation when the desired force exceeds the threshold and would produce dissipative power, and (3) the damper operates in its second mode of operation when the desired force is less than the threshold and would produce dissipative power.

On/off semi-active suspension control

Suspension apparatus provides a real time suspension tuning control for a motor vehicle. An actuator is connected to exert a variable force between the vehicle body and wheel. A control derives a control signal for the actuator from a linear combination of vehicle state variables derived from sensed vehicle variables, the linear combination being characterized by gains determining the relative contribution of each state variable to the control signal. The control further stores in memory a plurality of alternatives sets of gains, with each stored set of gains comprising gain values tending to produce a different suspension performance. The control is responsive to one of the sensed vehicle varibles in real time to select between the alternative sets of gains in deriving the control signal. The suspension tuning characteristics are thus easily and quickly changed in emphasis between isolation, wheel control and body attitude control in real time vehicle operation.

Vehicle suspension control with real time gain switching

A vehicle suspension system has at least one leveling device with a leveling sensor. Leveling action is ordinarily initiated when a sensor indicates height out of a dead band around the calibrated level for the sensor; however, such leveling action is prevented when the vehicle is not moving but has moved since the last opening of one or more selected vehicle doors.

Growing community of inventors

Centerville, OH, United States of America

Kamal N Majeed