Abstract: A module test machine includes a frame, a fixture, at most two actuators coupled to the fixture, and a controller. The frame is couplable to a first end of a strut module. The fixture is couplable to a second end of the strut module. The fixture includes a plurality of arms with a plurality of adjustable lengths. The at most two actuators are coupled to two of the plurality of arms and configured to impart a plurality of loads along six axes of force at the second end of the strut module. The controller is configured to control the at most two actuators in response to at most two actuator vectors. The plurality of adjustable lengths and the at most two actuator vectors are configured to replicate road load data at the second end of the strut module while under test.

Abstract: A module test machine includes a frame, a fixture, at most two actuators coupled to the fixture, and a controller. The frame is couplable to a first end of a strut module. The fixture is couplable to a second end of the strut module. The fixture includes a plurality of arms with a plurality of adjustable lengths. The at most two actuators are coupled to two of the plurality of arms and configured to impart a plurality of loads along six axes of force at the second end of the strut module. The controller is configured to control the at most two actuators in response to at most two actuator vectors. The plurality of adjustable lengths and the at most two actuator vectors are configured to replicate road load data at the second end of the strut module while under test.

Abstract: Disclosed are emulator architectures for steer-by-wire (SBW) vehicle systems, methods for making and for using such systems, and programmable control logic for operating emulator test systems. A method is disclosed for operating an emulator test system for motor vehicle SBW systems. The method includes a Central Processing Unit Workstation Controller (CWC) initiating a selected test procedure for the SBW system, and transmitting, to a Motor Controller (MC) of the test system, a target input curve corresponding to the initiated test procedure. The MC responsively commands a Driver Simulator Motor (DSM) to operate at a power input corresponding to the target input curve. An emulator, which is mechanically coupled to the DSM, transmits emulator state data resulting from operating the DSM to a Real-time Operating System (RTOS). The RTOS determines a vehicle response based on the emulator state data using a vehicle dynamics math model corresponding to the SBW system.

Abstract: A power steering assembly includes a steering unit and a motor. A controller includes a processor and tangible, non-transitory memory on which is recorded instructions for executing a method of self-diagnosis for the assembly. If a plurality of enabling conditions is met, the steering unit is caused to rotate through a plurality of angles from an original position, via a command to the motor. The steering unit is caused to rotate first in a forward direction up to a predefined maximum angle, second in a reverse direction up to a negative of the predefined maximum angle and third in the forward direction back to the original position. The controller is configured to obtain motor torque data characterizing torque of the motor at the plurality of angles. The assembly is controlled based at least partially on the motor torque data and predetermined baseline data.

Abstract: A power steering assembly includes a steering unit and a motor. A controller includes a processor and tangible, non-transitory memory on which is recorded instructions for executing a method of self-diagnosis for the assembly. If a plurality of enabling conditions is met, the steering unit is caused to rotate through a plurality of angles from an original position, via a command to the motor. The steering unit is caused to rotate first in a forward direction up to a predefined maximum angle, second in a reverse direction up to a negative of the predefined maximum angle and third in the forward direction back to the original position. The controller is configured to obtain motor torque data characterizing torque of the motor at the plurality of angles. The assembly is controlled based at least partially on the motor torque data and predetermined baseline data.

Abstract: Disclosed are emulator architectures for steer-by-wire (SBW) vehicle systems, methods for making and for using such systems, and programmable control logic for operating emulator test systems. A method is disclosed for operating an emulator test system for motor vehicle SBW systems. The method includes a Central Processing Unit Workstation Controller (CWC) initiating a selected test procedure for the SBW system, and transmitting, to a Motor Controller (MC) of the test system, a target input curve corresponding to the initiated test procedure. The MC responsively commands a Driver Simulator Motor (DSM) to operate at a power input corresponding to the target input curve. An emulator, which is mechanically coupled to the DSM, transmits emulator state data resulting from operating the DSM to a Real-time Operating System (RTOS). The RTOS determines a vehicle response based on the emulator state data using a vehicle dynamics math model corresponding to the SBW system.

Abstract: A method of tuning a calibration table for an electric power steering system includes connecting the electric power steering system to an actuator machine, and communicating a control input from a vehicle simulator to the actuator machine. Input forces and steering angles are applied to the electric power steering system with the actuator machine, based on the control input. The electric power steering system is controlled with a steering controller, to apply a steering setting, i.e., and assistive torque. The steering controller uses the calibration table to define the steering setting, based on the applied input forces and steering angles. A steering torque in the electric power steering system generated in response to the applied steering setting is sensed, and communicated to the vehicle controller, thereby establishing a closed loop, feedback system. The calibration table may then be re-defined based on the sensed steering response for the applied input forces.

Abstract: A method of tuning a calibration table for an electric power steering system includes connecting the electric power steering system to an actuator machine, and communicating a control input from a vehicle simulator to the actuator machine. Input forces and steering angles are applied to the electric power steering system with the actuator machine, based on the control input. The electric power steering system is controlled with a steering controller, to apply a steering setting, i.e., and assistive torque. The steering controller uses the calibration table to define the steering setting, based on the applied input forces and steering angles. A steering torque in the electric power steering system generated in response to the applied steering setting is sensed, and communicated to the vehicle controller, thereby establishing a closed loop, feedback system. The calibration table may then be re-defined based on the sensed steering response for the applied input forces.

Abstract: A method directed to improving the stability of a motor vehicle having front and rear steering capabilities includes determining a coefficient of friction of the road surface with which the motor vehicle is engaged and adjusting a phase gain function of a rear steering mechanism to compensate for the steerability of the motor vehicle over the road surface. A system for improving the stability of a motor vehicle having front and rear steering capabilities includes a control unit, a front steering mechanism in informational communication with the control unit, and a rear steering mechanism in informational communication with the control unit. The rear steering mechanism is responsive through the control unit to road conditions of the road surface.

Abstract: An all wheel steering system for a vehicle comprising a controller having a first input for receiving a signal from a hand wheel position sensor, a second input for receiving a signal from a vehicle speed sensor, and a third input for receiving a signal that varies depending upon whether a trailer is hitched the vehicle. The controller generates an output for controlling a rear wheel steering actuator. The output varies as a function of the first, second, and third inputs such that when a trailer is hitched to the vehicle the out-of-phase rear steer amount at low speeds is reduced and the in-phase rear steering amount at high speeds is increased.

Abstract: The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by an all-wheel steering system for a vehicle comprising a controller having a first input for receiving a signal from a hand wheel position sensor, a second input for receiving a signal from a vehicle speed sensor, and a third input for receiving a signal that varies depending upon whether a trailer is hitched to said vehicle. The controller generates an output for controlling a rear wheel steering actuator. The output varies as a function of the first, second, and third inputs such that when a trailer is hitched to said vehicle the out-of-phase rear steer amount at low speeds is reduced and the in-phase rear steering amount at high speeds is increased.

Abstract: A method of swing out compensation in a vehicle with rear wheel steering, comprising: obtaining a zero speed status signal representative of when a vehicle is at zero speed; establishing a rear wheel angle threshold; obtaining a calculated rear wheel angle; and generating a commanded rear wheel angle responsive to the rear wheel angle threshold and the calculated rear wheel angle, whichever is of smaller magnitude. A swing out compensation system for a vehicle with rear wheel steering, the system comprising: a controller; and a rear steering mechanism in communication with and responsive to the controller; wherein the controller generates a commanded rear wheel angle responsive to one of a rear wheel angle threshold and a calculated rear wheel angle, whichever is of smaller magnitude.

Abstract: A method is disclosed for controlling the rear wheel angle in a four-wheel steering vehicle such as a pickup truck. The front wheels are steered using the conventional operator handwheel linked to the front wheels. The rear wheels are actuated with a reversible electric motor and the rear wheel angle controlled using a computer with inputs of vehicle velocity, operator handwheel position and correlated front wheel angle, and handwheel turning rate. Control of rear wheel angle starts with a correlation of ratios of rear wheel angle to front wheel angle, R/F, vs. vehicle velocity suitable, determined under steady state front steering angle and velocity conditions, to maximize the contribution of the rear wheels while avoiding side-slip of the vehicle.

Abstract: A method is disclosed for controlling the rear wheel angle in a four-wheel steering vehicle such as a pickup truck. The front wheels are steered using the conventional operator handwheel linked to the front wheels. The rear wheels are actuated with a reversible electric motor and the rear wheel angle controlled using a computer with inputs of vehicle velocity, operator handwheel position and correlated front wheel angle, and handwheel turning rate. Control of rear wheel angle starts with a correlation of ratios of rear wheel angle to front wheel angle, R/F, vs. vehicle velocity suitable, determined under steady state front steering angle and velocity conditions, to maximize the contribution of the rear wheels while avoiding side-slip of the vehicle.

Abstract: A method directed to improving the stability of a motor vehicle having front and rear steering capabilities includes determining a coefficient of friction of the road surface with which the motor vehicle is engaged and adjusting a phase gain function of a rear steering mechanism to compensate for the steerability of the motor vehicle over the road surface. A system for improving the stability of a motor vehicle having front and rear steering capabilities includes a control unit, a front steering mechanism in informational communication with the control unit, and a rear steering mechanism in informational communication with the control unit. The rear steering mechanism is responsive through the control unit to road conditions of the road surface.

Abstract: Disclosed is a method of swing out compensation in a vehicle with rear wheel steering, comprising: obtaining a zero speed status signal representative of when a vehicle is at zero speed; establishing a rear wheel angle threshold; obtaining a calculated rear wheel angle; and generating a commanded rear wheel angle responsive to the rear wheel angle threshold and the calculated rear wheel angle, whichever is of smaller magnitude.

Abstract: Disclosed is a method of determining an estimate of zero speed of a vehicle, the method comprises obtaining or acquiring a drive train status signal, a brake signal, a parking brake signal, a vehicle speed signal, and a throttle position signal. The method further comprises formulating a zero speed status signal under selected conditions to in response to at least one of the abovementioned signals.