Abstract:
A control system and method for a steer-by-wire system with the passive resistance torque is provided. The control system includes a controller configured to compensate for a passive resistance torque and to generate the required active torque using a three loop control structure: torque feedback loop, rate feedback loop, and steering wheel angle feedback loop. The torque feedback loop is based on an estimated steering torque signal calculated from a steering angle signal, a steering angle rate signal, and a motor current signal.
Abstract:
The present invention involves a method for initial synchronization of steering wheel and a road wheels in a steer-by-wire system of a vehicle when the system is first powered. The method includes providing a steering wheel control system and a road wheel control system. The method further includes sensing relative angles and the absolute angles of the steering wheel, road wheel, and right road wheel. The method further includes generating an augmented steering wheel angle, an augmented left road wheel angle, and an augmented right road wheel angle based on the relative angle and initial value of the absolute angles of the steering wheel and road wheels. The method further includes using the augmented steering wheel angle as a feedback signal to the steering wheel control system and the augmented left and right road wheel angles feedback signals to the road wheels control system. The method further includes controlling the steering wheel and the road wheels to perform initial synchronization of the steering wheel and the road wheels, thereby allowing the vehicle to be operable during the initial synchronization.
Abstract:
The present invention involves a method of controlling a vehicle steer-by-wire system having two independent road wheels. In one embodiment, the method comprises providing a steering wheel control sub-system to generate road wheel reference angles and to produce steering feel for a vehicle driver. The method further includes providing a road wheel control subsystem with servo control structure having road wheel angles and angular rates feedbacks including a road wheel controlled plant and a road wheel controller for controlling actual road wheel angles to track to road wheel reference angles. Moreover, a robust control is implemented in the road wheel controller to overcome affects of uncertainties and disturbances from the steer-by-wire system, vehicle, and external environment.
Abstract:
The present invention involves a system and method of controlling a steer-by-wire system to produce adjustable steering feel for A vehicle driver by providing control of reaction torque on a steering wheel of a vehicle. The method includes a quantitative description for the steering feel which is obtained by establishing a relationship of steering wheel reaction torque and steering wheel angle, road wheel torque, and vehicle speed. The system and method include steer-by wire system closed-loop feedback controls with inner torque loop, steering wheel rate feedback loop, and steering wheel angular position feedback loop to implement providing the steering feel, active steering wheel return with the different rotation rate, steering wheel stop according to the road wheel angular position in a parking state, and directional angle reference generation to road wheels.
Abstract:
The present invention involves a system and method of controlling a steering wheel for simulated steering feel on a steering wheel of a vehicle with front road wheels in a steer-by-wire system. The method includes sensing actual torsion on the steering wheel, comparing the actual torsion to a threshold torque value, sensing actual angular velocity of the steering wheel, and comparing the actual angular velocity to a threshold angular velocity. The method further includes generating a simulated steering feel torque on the steering wheel, if the actual torsion is greater than the threshold torque value and the actual angular velocity is less than the threshold angular velocity. The method further comprises returning the steering wheel to the center position at a specified angular velocity, if the actual torsion is less than the threshold torque value and the actual angular velocity is greater than the threshold angular velocity.
Abstract:
A method and system for sensing angular displacement is provided. More specifically, the system includes a brushless DC motor, three Hall effect sensors, an angular displacement signal processor, and an output state observer. The Hall effect sensors provide three electrical angles of the motor rotor which are used in an angular displacement signal processor that is implemented in hardware and software. The angular displacement signal processor provides an improved resolution angular displacement output. Based on the angular displacement output from angular displacement signal processor and the motor control command signal from the motor drive, an output state observer is applied to generate a high resolution angular displacement signal.
Abstract:
The present invention involves a method and system of initial aligning wheels of vehicle steer-by-wire systems with two independent front road wheels in the real time. The method comprises providing a steering wheel control sub-system and a road wheel control sub-system, providing an initial alignment unit and procedure to align the road wheels and steering wheel, and receiving relative and absolute steering wheel angles and road wheel angles. The method further includes generating wheel aligning reference angles based on the relative and absolute wheel angle, generating the switch control signal based wheel aligning reference angles using the logic operation with the threshold, and determining the steer-by-wire systems in the control state or in the initial alignment state.
Abstract:
The present invention involves a system and method of controlling a variable steering ratio of a vehicle steer-by-wire system. The variable steering ratio control varies the steering ratio continuously according to steering angle and vehicle speed. The method comprises sensing an actual steering wheel angle and an actual speed of the vehicle and converting the actual steering wheel angle and vehicle speed into values in fuzzy sets based on a steering wheel angle and vehicle speed membership functions with linguistic term labels. The method further includes determining a corresponding degree of membership of the steering wheel angle and vehicle speed. The method further includes inferring a fuzzy road wheel reference angle output value by determining the degree of membership function for the road wheel reference angle using fuzzy rules based on the degrees of steering angle and the vehicle speed. The method further includes converting a fuzzy road wheel angle into an actual road wheel angle. The variable steering ratio can be adjusted according to the vehicle operator's desire with a progressive ratio setup.
Abstract:
One aspect of the present invention regards an automotive steering wheel control system having a steering wheel, a magnetorheological damper in communication with the steering wheel and a road wheel control system operably connected to the magnetorheological damper where the magnetorheological damper controls the steering wheel in response to a torque signal from the road wheel control system.
Abstract:
The present invention involves a method of controlling a vehicle steer-by-wire system having two independent road wheels. In one embodiment, the method comprises providing a steering wheel control sub-system to generate road wheel reference angles and to produce steering feel for a vehicle driver. The method further includes providing a road wheel control sub-system including a road wheel controlled plant and a road wheel controller for controlling actual road wheel angles to track to road wheel reference angles. Moreover, the method includes applying road wheel angles and angular rates as feedback signals to implement the left and right road wheel angles tracking for left and right road wheel reference angles in the road wheel control system with servo control system structure. The method further includes implementing a gain scheduling control in the road wheel controller to compensate the gain change of the controlled road wheel plant for overcoming non-linearity of the road wheel system, The present invention also involves a system of controlling a vehicle steer-by-wire system applying gain scheduling.