Gm Global Technolgoy Operations, Inc.

Scott R Kloess

John T Zuzelski

Christopher J Mielke

Ibrahim A Badiru

Jose M Lopez

Bo Yu

Miroslaw Zaloga

George E Doerr

Yat-chung Tang

Mauro Pacheco Escobedo

Robert S Brines

Darrin S Mallard

Charles J Lemont, Jr

David C Pomerville

Chandra S Namuduri

Suresh Gopalakrishnan

William Charles Kruckemeyer

Kenneth L Oblizajek

Kevin Gerard Leppek

Allen John Walenty

John D Sopoci

David M Sidlosky

Wayne V Fannin

Stephen R Pastor

Eric L Raphael

William C Gregory

Michael C Gaunt

William R Venner

Marc J Tahnoose

Robert W Leschuk

Kenneth L Rosol

Brian N Siskoy

Silviu A Popescu

Terrel D Johnson

Charu S Hayes

R Larry Arbanas

Lin Wang

Hossam Almasri

Terry R Peterson

Marissa J West

Nicholas V Katcherian

Examples of techniques for estimating stability margins in a steer-by-wire system are disclosed. In one example implementation, a method for open-loop steer-by-wire (SbW) system linearization includes linearizing, by a processing device, an open-loop SbW system at different operating points. The method further includes determining, by the processing device, an open-loop transfer function of the op en-loop SbW system. The method further includes estimating, by the processing device, margins of stability for the open-loop SbW system. The method further includes implementing the margins of stability into a vehicle to reduce instability in a steering system of the vehicle.

Estimating stability margins in a steer-by-wire system

Methods and apparatus are provided for damage risk indication of a steering system of a vehicle. The apparatus includes a sensor system and a processing device. The sensor system is configured to detect a velocity of a servo unit of a steering system of the vehicle. The processing device is configured to determine an acceleration value of the servo unit and to compare the acceleration value, velocity values and thresholds of the servo unit with an acceleration value threshold, and to generate a warning signal if the acceleration value of the servo unit exceeds the acceleration value threshold. Thus, a damage risk is determined and the vehicle can be subjected to further damage investigation.

Overload and overspeed detection of electric power steering systems

A vehicle and a steering system of a vehicle. The steering system includes a steering column emulator that generates an electrical driving signal in response to a driver input, a steering rack assembly that receives the electrical driving signal from the steering column emulator and controls steering of the vehicle as indicated by the received signal, and a backup system. The backup system provides a backup electrical driving signal to the steering rack assembly upon a failure of the steering column emulator, and the steering rack assembly steers the vehicle as indicated by the backup electrical driving signal upon the failure of the steering column emulator.

Fail operational control of steer-by-wire system without mechanical backup connection

Systems and methods for monitoring the state of charge of a battery of a vehicle are provided. A battery monitor having a processor and a memory is configured to monitor an operating voltage and a loaded voltage of the battery. An electric power steering system is configured to be supplied with power from the battery. The battery monitor is configured to calculate a voltage drop between the operating voltage and the loaded voltage when the battery is under load from the electric power steering system. The battery monitor compares the voltage drop to a predetermined voltage drop and determines that the state of charge of the battery is low when the voltage drop is greater than or equal to the predetermined voltage drop. The battery monitor instructs the electric power steering system to operate in a limited state when the state of charge of the battery is low.

System and method for monitoring a state of charge of a battery

Methods and apparatus are provided for controlling a steering assist unit of a vehicle. The method includes receiving first accelerometer data, second accelerometer data, and third accelerometer data then comparing and calculating differences between the first accelerometer data, second accelerometer data and the third accelerometer data to determine a relative movement values for the second and third locations. The relative movement value represents the contraction or expansion of separate systems as they independently move at or near the second and third locations. The method further includes outputting a control signal to control the travel of the steering assist unit based on the relative movement values.

Systems and methods for variable steering assist-II

Methods and systems are provided for monitoring a steering system of a vehicle. In one embodiment, a method includes: receiving torque signal data corresponding to torque signals received from a torque sensor associated with the steering system; processing the torque signal data to determine an average torque value; determining a health status of an alignment of the steering system based on the average torque value; and generating at least one of a signal, a message, and a code to notify a user based on the health status.

Methods and systems for performing steering alignment health checks

In one embodiment, a method for steering system integrity testing includes positioning the vehicle with the second traction wheel within a first constraint; applying mechanical load to the first traction wheel; receiving data corresponding to a steering system operating condition; positioning the vehicle with the first traction wheel within a second constraint; applying mechanical load to the second traction wheel; receiving data corresponding to a steering system operating condition; positioning the vehicle with the first and second traction wheels on respective first and second friction surfaces; applying mechanical load to the first and second traction wheels; receiving data corresponding to a steering system operating condition; transmitting the data to a processor; and determining, via the processor, a health status of the steering system based on the data.

Methods and systems for steering system integrity testing

A steering system for an autonomously driven vehicle and methods of steering the vehicle are disclosed. A main controller signals a secondary steering assembly to operate in a first phase when a power steering controller is in a first mode and a second phase to steer the vehicle when the power steering controller is in a second mode. The main controller signals a friction device to actuate to a disengaged position when the power steering controller is in the first mode and the secondary steering assembly is in the first phase, and to signal the friction device to actuate to an engaged position to secure a steering wheel in an initial position when the power steering controller is in the second mode and the secondary steering assembly is in the second phase to allow the secondary steering assembly to steer the vehicle.

Steering system for an autonomously driven vehicle and methods of steering the same

A power steering system for transferring torque to a sector gear includes a first ball screw and a first ball nut circumscribing the first ball screw. The first ball nut is in torque-transfer communication with the first ball screw through a plurality of ball bearings and is meshed or engaged with the sector gear for torque transfer therewith. An electric motor is configured to selectively supply torque to the sector gear through the first ball nut.

Recirculating ball power steering system

A power steering system includes an input shaft operatively connected to an input member, and a sector gear operatively connected to a pitman arm. A first ball screw is formed on the input shaft. A first ball nut circumscribes the first ball screw and is in torque-transfer communication therewith through a plurality of ball bearings. A first rack is rigidly attached to the first ball nut, and is meshed with the sector gear for torque transfer therewith. A second ball screw is not substantially coaxial with the first ball screw. A second ball nut circumscribes the second ball screw and is in torque-transfer communication with the second ball screw through the ball bearings. A second rack is meshed with the sector gear for torque transfer therewith. An electric motor is configured to selectively supply torque to the sector gear through the second ball screw.

A method of controlling a motor current for a vehicle having a motor and a steering system includes the steps of obtaining a torque signal from the steering system, calculating a torque, and adjusting the motor current based at least in part on the torque signal, the torque gain, or both.

Methods and systems for controlling motor current in steering systems of vehicles equipped with electric steering assist

A method for improving a failure mode diagnostic of an electric power steering system by overcoming a motor electric lock condition due to position sensor signal corruption or other motor faults. If certain conditions are met, the method determines that the motor is in an electric lock condition, and then reduces a torque current command to the motor so that it is able to be rotated by a vehicle hand-wheel. Once the motor is able to be rotated, then the method determines whether certain conditions have been met to determine whether the position sensor is malfunctioning.

Electric power steering control

A method of determining steering rack rattle propensity of a rack and pinion steering assembly may comprise: simultaneously recording audio, and measuring acceleration of a rack, and right and left side tie-rod end loads; identifying rack rattle events from the audio recording; determining common characteristics of the measured rack acceleration and tie-rod end loads during the identified rack rattle events; creating a rack rattle index level; applying a predetermined force profile to a test rack and pinion steering assembly; measuring a test acceleration on the test rack and pinion steering assembly; calculating a test RMS level in a test frequency range using a test time constant; determining a rack rattle index value from the calculated test RMS level; and comparing the rack rattle index value to the rack rattle index level.

Test procedure for determining steering rack rattle

A wear compensator for use in a vehicle rack and pinion steering assembly and a method of biasing a rack against a pinion shaft gear in a rack and pinion steering assembly are disclosed. The wear compensator may include a rack follower, an adjuster plug, a wear cam and a torsion spring. The rack follower slides on the rack. The adjuster plug is retained by the steering gear housing and includes a plug cam surface. The wear cam includes a wear cam surface operatively engaging the plug cam surface, is mounted between the rack follower and the adjuster plug, and can rotate relative to the adjuster plug. The torsion spring connects between the adjuster plug and the wear cam in order to rotatably bias the wear cam relative to the adjuster plug.

Steering rack wear compensator

A control for an automatic shifting power transmission employs an algorithm to determine the proper gear ratio during vehicle deceleration. The algorithm establishes downshift grade requirements based on the brake pressure and speed threshold targets based on brake pressure. A grade average is calculated from the operating parameters of acceleration, engine braking, aerodynamic drag, rolling resistance and brake torque deceleration. If the grade average is within downshifting range and the speed target is met, the control commands a downshift to the next lower gear ratio. The downshift grade requirements decrease as brake pressure increases and speed targets increase as brake pressure increases.

Growing community of inventors

Rochester Hills, MI, United States of America

Scott R Kloess