Abstract: According to one or more embodiments, a steer by wire steering system includes a handwheel actuator, a roadwheel actuator, and a resynchronization module to dynamically adjust handwheel position that is used for rack position reference calculation. The dynamic adjustment includes determining a desynchronization amount based on a difference in an actual handwheel position and a synchronized handwheel position. The dynamic adjustment further includes computing a handwheel adjustment using the desynchronization amount, a vehicle speed, and a handwheel speed. The dynamic adjustment further includes computing an adjusted handwheel position based on the handwheel adjustment and the actual handwheel position. The dynamic adjustment further includes updating the reference rack position based on the adjusted handwheel position. The dynamic adjustment is continuously repeated until the handwheel adjustment is substantially equal to zero.

Abstract: According to one or more embodiments, a steer by wire steering system includes a handwheel, and a handwheel actuator configured to secure a position of the handwheel. The securing includes determining a transition of the steer by wire steering system to an ingress/egress mode. The securing further includes, based on the determination that the steer by wire steering system is in the ingress/egress mode, computing a holding torque command based on a difference in a present angle of the handwheel and a target angle of the handwheel, which is caused by an input torque. Further, the securing includes generating a holding torque corresponding to the holding torque command to secure the position of the handwheel.

Abstract: Technical solutions are described for disturbance feedforward compensation technique for improving the disturbance rejection properties of a closed loop position control system using a cascaded control structure with an inner velocity and outer position control loops. According to one or more embodiments, a system includes a position controller that receives an input rack-position command, and a measured rack-position, and computes a velocity command based on a difference in the input rack-position command and the measured rack-position. The system further includes a velocity controller that receives the velocity command, and a measured motor velocity, and computes an input torque command based on a difference in the velocity command and the measured motor velocity. The system adjusts a position of a rack by generating an amount of torque corresponding to the applying the input torque command to a motor.

Abstract: Technical solutions are described for disturbance feedforward compensation technique for improving the disturbance rejection properties of a closed loop position control system. According to one or more embodiments, a steering system includes a position controller that generates a torque command based on an input rack-position command and a measured position command. Further, a disturbance estimator that estimates a rack force acting on a rack, and an adder generates an adjusted torque command by adding the rack force that is estimated into the torque command. The steering system further includes an actuator that positions the rack according to the adjusted torque command.

Abstract: According to one or more embodiments a control system for a steering system, includes a control module that estimates a tire load by performing a method that includes receiving, as an input torque, motor-torque that is generated by a motor of the steering system. The method further includes computing an efficiency factor for a gear of the steering system based on the input torque and a motor velocity. The method further includes adjusting the input torque by scaling the input torque with the efficiency factor. The method further includes estimating the tire load using the adjusted input torque as an input to a state observer for the steering system.

Abstract: According to one or more embodiments, a steer by wire steering system includes a handwheel actuator, a roadwheel actuator, and a resynchronization module to dynamically adjust handwheel position that is used for rack position reference calculation. The dynamic adjustment includes determining a desynchronization amount based on a difference in an actual handwheel position and a synchronized handwheel position. The dynamic adjustment further includes computing a handwheel adjustment using the desynchronization amount, a vehicle speed, and a handwheel speed. The dynamic adjustment further includes computing an adjusted handwheel position based on the handwheel adjustment and the actual handwheel position. The dynamic adjustment further includes updating the reference rack position based on the adjusted handwheel position. The dynamic adjustment is continuously repeated until the handwheel adjustment is substantially equal to zero.

Abstract: According to one or more embodiments, a steer by wire steering system includes a handwheel, and a handwheel actuator configured to secure a position of the handwheel. The securing includes determining a transition of the steer by wire steering system to an ingress/egress mode. The securing further includes, based on the determination that the steer by wire steering system is in the ingress/egress mode, computing a holding torque command based on a difference in a present angle of the handwheel and a target angle of the handwheel, which is caused by an input torque. Further, the securing includes generating a holding torque corresponding to the holding torque command to secure the position of the handwheel.

Abstract: Technical solutions are described for disturbance feedforward compensation technique for improving the disturbance rejection properties of a closed loop position control system using a cascaded control structure with an inner velocity and outer position control loops. According to one or more embodiments, a system includes a position controller that receives an input rack-position command, and a measured rack-position, and computes a velocity command based on a difference in the input rack-position command and the measured rack-position. The system further includes a velocity controller that receives the velocity command, and a measured motor velocity, and computes an input torque command based on a difference in the velocity command and the measured motor velocity. The system adjusts a position of a rack by generating an amount of torque corresponding to the applying the input torque command to a motor.

Abstract: Technical solutions are described for disturbance feedforward compensation technique for improving the disturbance rejection properties of a closed loop position control system. According to one or more embodiments, a steering system includes a position controller that generates a torque command based on an input rack-position command and a measured position command. Further, a disturbance estimator that estimates a rack force acting on a rack, and an adder generates an adjusted torque command by adding the rack force that is estimated into the torque command. The steering system further includes an actuator that positions the rack according to the adjusted torque command.

Abstract: According to one or more embodiments a control system for a steering system, includes a control module that estimates a tire load by performing a method that includes receiving, as an input torque, motor-torque that is generated by a motor of the steering system. The method further includes computing an efficiency factor for a gear of the steering system based on the input torque and a motor velocity. The method further includes adjusting the input torque by scaling the input torque with the efficiency factor. The method further includes estimating the tire load using the adjusted input torque as an input to a state observer for the steering system.

Abstract: Technical solutions are described for a power steering system of a vehicle to estimate tire load. An example control system of a power steering includes a control module to receive sensor data and control the power steering system. For example, the control module determines an estimated friction torque of a rack connected to the steering system, compute an input torque to the rack, the input torque being a sum of the estimated friction torque, a handwheel torque, and a motor torque, and further determine a rack position estimate based on the input torque, a handwheel angle, and a vehicle speed. Further, in response to the rack position estimate being computed, the control module computes a tire load estimate from the rack position estimate.

Abstract: A system for detecting handwheel control comprises a driver torque estimation module that estimates a driver torque state based on a plurality of electric power steering signals; and a grip detection module that determines one of a grip level, a hands-on wheel flag, and a transition blending factor from the driver torque state, the grip level is used to control a driver assist power steering system.

Abstract: A system and a method of controlling a power steering system of a vehicle are provided. A control system includes a control module operable to determine a rack force of the vehicle based on at least one of a motor velocity, a driver torque and a motor torque, determine a plurality of modeled rack forces based on a roadwheel angle and a vehicle speed, compare the rack force to the plurality of modeled rack forces to generate a friction level included in a control signal, and send the control signal to the power steering system.

Abstract: A system for detecting handwheel control comprises a driver torque estimation module that estimates a driver torque state based on a plurality of electric power steering signals; and a grip detection module that determines one of a grip level, a hands-on wheel flag, and a transition blending factor from the driver torque state, the grip level is used to control a driver assist power steering system.

Abstract: A system and a method of controlling a power steering system of a vehicle are provided. A control system includes a control module operable to receive sensor data and control the power steering system. The control module is configured to determine whether the vehicle is operating in a low surface friction condition based on a handwheel angle and one of a handwheel torque and a pinion torque. The control module generates a control signal based on the determination and sends the control signal to the power steering system.

Abstract: A system and a method of controlling a power steering system of a vehicle are provided. A control system includes a control module operable to determine a rack force of the vehicle based on at least one of a motor velocity, a driver torque and a motor torque, determine a plurality of modeled rack forces based on a roadwheel angle and a vehicle speed, compare the rack force to the plurality of modeled rack forces to generate a friction level included in a control signal, and send the control signal to the power steering system.

Abstract: A system and a method of controlling a power steering system of a vehicle are provided. A control system includes a control module operable to receive sensor data and control the power steering system. The control module is configured to determine whether the vehicle is operating in a low surface friction condition based on a handwheel angle and one of a handwheel torque and a pinion torque. The control module generates a control signal based on the determination and sends the control signal to the power steering system.