Steering Solutions IP Holding Corporation

Rangarajan Ramanujam

Prerit Pramod

Anthony J Champagne

Tejas M Varunjikar

Bhuvanesh Sainath

Rakesh Mitra

Jeffrey M Otto

Apurv Naman

Julie Ann Kleinau

Steven D Klein

Scott T Sanford

Dennis B Skellenger

Zhe Zhang

Mariam Swetha George

Michael S Wyciechowski

Michael A Eickholt

Michael Story

Tao Yang

Owen K Tosh

Technical solutions described herein include a method of controlling an electric power steering system includes determining that one or more hand wheel torque sensors of electric power steering system are not operational and in response generating an assist torque command by estimating a front slip angle based on a motor angle of a motor of the electric power steering system and a vehicle speed. The method also includes converting the front slip angle to a rack force. The method also includes determining an amount of assist torque based on the rack force and controlling the electric power steering system using the generated assist torque command.

Providing assist torque in steering systems operating without a torque sensor

A steer by wire system includes a controller operable to operate a roadwheel actuator such that a position command to the roadwheel actuator based on a handwheel orientation is a magnitude corresponding to a handwheel orientation offset value in an opposite direction to reduce a difference between the handwheel orientation offset value and a predetermined handwheel zero value.

Steer by wire drift compensation

According to one or more embodiments of the technical solutions described herein, a method for generating torque in a steering system includes computing, by a controller, a lateral velocity of a vehicle using a vehicle model that uses a vehicle velocity, a surface friction estimate, a tire-angle, and at least one of a measured yaw rate from a yaw rate sensor and a lateral acceleration. The method further includes generating, by the controller, a torque command for providing assist torque to a driver, the torque command is based on the lateral velocity that is computed. The method further includes providing, by a motor, the assist torque, which is an amount of torque corresponding to the torque command.

Rack force estimation for steering systems

A method for generating torque assist includes determining a model yaw rate value based on a vehicle speed, a steering angle, and a road-friction coefficient value and determining a differential yaw rate value using a difference between the model yaw rate value and a vehicle yaw rate value. The method also includes determining an updated road-friction coefficient value using at least the differential yaw rate value and generating a torque assist value based on the updated road-friction coefficient value and a model rack force value.

Dynamic vehicle model based assist without torque sensor

A method for damping dependent scaling for reducing wheel imbalance in a steering system includes determining roadwheel speed energy using a roadwheel speed signal and determining that the roadwheel speed energy is greater than a predetermined energy threshold, and in response: adjusting the roadwheel speed signal; and computing a wheel imbalance reduction command using the adjusted roadwheel speed signal. The method also includes determining that the roadwheel speed energy is not greater than the predetermined energy threshold, and in response computing the wheel imbalance reduction command using the roadwheel speed signal. The method also includes computing a motor torque command using the wheel imbalance reduction command, the motor torque command used to generate a corresponding amount of torque at a handwheel.

Steering system with damping dependent scaling for wheel imbalance induced vibration reduction

A method includes receiving a first input indicating at least a selected controller type and generating, based on the first input, a model that represents a controller corresponding to the selected controller type. The method also includes receiving a second input indicating at least one functional aspect of the selected controller type, updating, based on the second input, the model to represent the at least one functional aspect of the selected controller type, and compiling, using the model, a binary file that represents, at least, the at least one functional aspect of the selected controller type. The method also includes uploading the binary file to a controller corresponding to the selected controller type.

Middleware system and method

According to the technical solutions described herein, an example method for frequency tracking based friction detection includes receiving, by a filter module, an accelerometer signal from an accelerometer coupled with an assist torque system. The method further includes estimating, by the filter module, harmonic content in the accelerometer signal based on an order frequency of the assist torque system. The method further includes in response to the harmonic content that is detected being greater than or equal to a predetermined threshold, initiating a friction estimation in the assist torque system. The method further includes adjusting an amount of torque being generated by the assist torque system based on an estimated friction in the assist torque system.

Frequency tracking based friction detection using accelerometer

Technical solutions are described for lash detection diagnostic in a steering system. An example method includes sending, by a controller, an excitation motor command to a motor control system. The method further includes measuring, by the controller, a sensor signal generated in response to the excitation motor command. The method further includes determining, by the controller, a decay rate of a change in magnitude of the signal at a plurality of frequencies. The method further includes diagnosing, by the controller, that the steering system has a lash condition based on the decay rate exceeding a predetermined threshold.

Lash detection startup diagnostic

Technical solutions are described for current sensor fault mitigation for systems with permanent magnet DC drives. An example power steering system includes a brush motor, and a motor control system that generates an amount of torque using the brush motor, the amount of torque corresponding to a torque command. The motor control system includes a current sensor fault detector that detects a current sensor fault associated with a current sensor used to measure a current across the brush motor. The motor control system further includes a velocity observer that computes an estimated motor velocity in response to the current sensor fault. The motor control system further includes a feedforward controller that generates a current command for generating the amount of torque using the brush motor, the current command generated using the estimated motor velocity.

Current sensor fault mitigation for steering systems with permanent magnet DC drives

One or more embodiments are described for preventing controller windup in a motion control system. An example system includes a regulator that receives an input command to adjust a motion control variable of a mechanical system that includes a motor, the regulator configured to generate a first torque command based on the input command and an output torque from the motor. The system further includes a motor control module that receives the first torque command to generate an input torque command that is sent to the motor. The system further includes an anti-windup module that is configured to generate an anti-windup command based on the first torque command and the output torque, the anti-windup command being added to the input command that is sent to the regulator.

Compensator anti-windup for motion control systems

According to one or more embodiments of the present invention a steer by wire steering system includes a deviation detection unit configured to determine a deviation signal that is indicative of a disturbance in one or more components coupled to a rack. The steer by wire steering system further includes a handwheel notification module configured to generate a modification signal based on the deviation signal, in response to the deviation signal being detected for at least a predetermined duration. The steer by wire steering system further includes a handwheel control module that generates an input command corresponding to a reference torque generated by a road wheel actuator, a feedback torque for a driver is generated based on the input command. The handwheel control module further modifies the input command using the modification signal, the modification providing a notification corresponding to the disturbance to the driver.

Driver notification using handwheel actuators in steer-by-wire systems

Technical solutions are described for facilitating an electric power steering (EPS) system to determine an operating mode of a vehicle that is equipped with the EPS, where the operating mode is indicative of a level of autonomous driving being used by the vehicle. The technical solutions further facilitate detecting a change in the operating mode of the vehicle, and facilitating a transition in computing an assist signal for the EPS system during the transition between the operating modes.

Electric power steering mode determination and transitioning

Technical features are described for a steering system to compute a state flag value that is indicative of a vehicle motion state, such as an understeer or an oversteer condition. The steering system further generates a reference torque signal based on the state flag value, and generates a motor-assist torque signal based on the reference torque signal. The state flag value indicates the vehicle motion state in both a dynamic-state or a steady-state. Further, the steering system generates the reference torque signal based on the state flag value by blending a first rack force generated based on a vehicle-speed signal and motor angle, and a second rack force generated based on a motor torque and an input torque provided to a handwheel of the steering system.

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Saginaw, MI, United States of America

Rangarajan Ramanujam