Abstract: A system comprises a processor and a memory storing instructions which when executed by the processor configure the processor to estimate a rack force for a steering system of a vehicle based on current driving and environmental conditions and estimate a health of an actuator of the steering system of the vehicle. The instructions configure the processor to estimate maximum achievable angle, velocity, and acceleration for the actuator of the steering system based on the estimated rack force and the estimated health of the actuator. The instructions configure the processor to provide to the steering system a path planned for the vehicle based on the estimated maximum achievable angle, velocity, and acceleration for the actuator of the steering system.

Abstract: A system comprises a processor and a memory storing instructions which when executed by the processor configure the processor to estimate a rack force for a steering system of a vehicle based on current driving and environmental conditions and estimate a health of an actuator of the steering system of the vehicle. The instructions configure the processor to estimate maximum achievable angle, velocity, and acceleration for the actuator of the steering system based on the estimated rack force and the estimated health of the actuator. The instructions configure the processor to provide to the steering system a path planned for the vehicle based on the estimated maximum achievable angle, velocity, and acceleration for the actuator of the steering system.

Abstract: An exemplary method for identifying and removing load biases correlated to a vehicle braking system includes providing a first vehicle sensor configured to measure a vehicle brake pressure of a vehicle brake assembly, providing a second vehicle sensor configured to measure one or more vehicle characteristics, providing a controller in communication with the first and second vehicle sensors, the vehicle brake assembly, and a vehicle steering system, receiving first sensor data indicative of the vehicle brake pressure and second sensor data indicative of the one or more vehicle characteristics, determining if a first condition is satisfied, and if the first condition is satisfied, generating a characterization table based on the first and second sensor data, and determining a brake-induced steering load from the first and second sensor data, wherein the characterization table includes data indicative of a relationship between the first and second sensor data.

Abstract: A method for optimizing vehicle steer-by-wire characteristics, includes collecting steer-by-wire steering system data for multiple predetermined data segments. Multiple driving quality objective indices are determined for each segment. A trend line is prepared based on the multiple predetermined data segments using a first algorithm, a second algorithm and a third algorithm, each assigned to one of the driving quality objective indices. Values obtained from the first algorithm, the second algorithm and the third algorithm are superimposed to create a net desired incremental change in damping, steering ratio and base assist. A steering calibration modification command is generated in real-time using the incremental change in damping, steering ratio and base assist.

Abstract: A method to evaluate a quality of road feedback to a driver in a steer-by-wire system includes setting a test bench by grounding a steering system steering wheel using a physical 6th order impedance constraint; preloading the steering system with data defining a steering wheel angle and a vehicle speed; applying tie rod load signals to the steering system and recording signals representing each of a tie rod load, a steering wheel torque and a steering wheel acceleration. In parallel: applying first a fast Fourier transform algorithm to the recorded signals to calculate each of a gain, a phase and a coherence response from the tie rod load to the steering wheel torque; applying second a fast Fourier transform algorithm to the recorded signals to calculate a power spectral density of the steering wheel torque versus frequency; and applying frequency weighting functions to the gain and power spectral density functions.

Abstract: 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.

Abstract: An exemplary method for identifying and removing load biases correlated to a vehicle braking system includes providing a first vehicle sensor configured to measure a vehicle brake pressure of a vehicle brake assembly, providing a second vehicle sensor configured to measure one or more vehicle characteristics, providing a controller in communication with the first and second vehicle sensors, the vehicle brake assembly, and a vehicle steering system, receiving first sensor data indicative of the vehicle brake pressure and second sensor data indicative of the one or more vehicle characteristics, determining if a first condition is satisfied, and if the first condition is satisfied, generating a characterization table based on the first and second sensor data, and determining a brake-induced steering load from the first and second sensor data, wherein the characterization table includes data indicative of a relationship between the first and second sensor data.

Abstract: A method for optimizing vehicle steer-by-wire characteristics, includes collecting steer-by-wire steering system data for multiple predetermined data segments. Multiple driving quality objective indices are determined for each segment. A trend line is prepared based on the multiple predetermined data segments using a first algorithm, a second algorithm and a third algorithm, each assigned to one of the driving quality objective indices. Values obtained from the first algorithm, the second algorithm and the third algorithm are superimposed to create a net desired incremental change in damping, steering ratio and base assist. A steering calibration modification command is generated in real-time using the incremental change in damping, steering ratio and base assist.

Abstract: 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.

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: 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.

Abstract: An electronic control unit for a steer-by-wire vehicle steering system includes a data storage component that stores a desired lateral acceleration versus steering angle profile with regard to a range of vehicle speeds and a processor operably and electronically coupled with a steering wheel angle sensor and a yaw sensor. The data storage component includes electronic instructions that causes the processor to receive steering wheel angle data over a range of vehicle speeds, receive vehicle yaw data over the range of vehicle speed correlated to the steering wheel angle data, generate an observed lateral acceleration versus steering angle profile with regard to the range of vehicle speeds, and generate a steering ratio correction based on a comparison of the desired lateral acceleration versus steering angle profile and the observed lateral acceleration versus steering angle profile.

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 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.

Abstract: An electronic control unit for a steer-by-wire vehicle steering system includes a data storage component that stores a desired lateral acceleration versus steering angle profile with regard to a range of vehicle speeds and a processor operably and electronically coupled with a steering wheel angle sensor and a yaw sensor. The data storage component includes electronic instructions that causes the processor to receive steering wheel angle data over a range of vehicle speeds, receive vehicle yaw data over the range of vehicle speed correlated to the steering wheel angle data, generate an observed lateral acceleration versus steering angle profile with regard to the range of vehicle speeds, and generate a steering ratio correction based on a comparison of the desired lateral acceleration versus steering angle profile and the observed lateral acceleration versus steering angle profile.

Abstract: A method of quantifying a viscous damping steering feel characteristic of a vehicle equipped with an electric power steering system includes connecting the electric power steering (EPS) system to a rotary actuator and kingpin actuators of a simulator system, communicating a triangle wave control input from a simulator controller to the rotary actuator, and receiving outputs from sensors in the simulator system by the simulator controller in response to the triangle wave control input. The simulator controller is programmed to execute logic embodying a method using the triangle wave control input provided via the rotary actuator and deconvolution of the outputs remove phase lag between the input and output signals, to generate a deconvoluted hysteresis loop for each of a plurality of steering cycles conducted during a vehicle simulation event, and to characterize a viscous damping steering feel characteristic of the EPS system.

Abstract: 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.

Abstract: A method of quantifying a viscous damping steering feel characteristic of a vehicle equipped with an electric power steering system includes connecting the electric power steering (EPS) system to a rotary actuator and kingpin actuators of a simulator system, communicating a triangle wave control input from a simulator controller to the rotary actuator, and receiving outputs from sensors in the simulator system by the simulator controller in response to the triangle wave control input. The simulator controller is programmed to execute logic embodying a method using the triangle wave control input provided via the rotary actuator and deconvolution of the outputs remove phase lag between the input and output signals, to generate a deconvoluted hysteresis loop for each of a plurality of steering cycles conducted during a vehicle simulation event, and to characterize a viscous damping steering feel characteristic of the EPS system.