Patent ID: 6928352
Filing Date: 2005-08-09
Classification: B62D

Abstract:
1. A method of initial aligning wheels of a vehicle steer-by-wire system with two independent front road wheels in real time, the method comprising: sensing absolute and relative steering wheel angles, absolute and relative left road wheel angles, and absolute and relative right road wheel angles; generating wheel aligning reference angles including a steering wheel aligning reference angle, a left road wheel aligning reference angle, and a right road wheel aligning reference angle; generating a switch control signal to determine operating states of the steer-by-wire system defining an initial alignment state and a nominal control state, the switch control signal being generated based on the steering wheel and road wheel aligning reference angles between the relative angles and absolute angles by using a logic operation with a switch threshold; maintaining the initial alignment state wherein the steering wheel and road wheel aligning reference angles are connected to be input signals in the steer-by-wire control system, if one of the steering wheel aligning reference angle, the left road wheel aligning reference angle, and the right road wheel aligning reference angle is greater than the switch threshold between initial alignment state and nominal control state; aligning the left road wheel, the right road wheel, and the steering wheel based on the steering wheel aligning reference angle, the lef: road wheel aligning reference angle, and the right road wheel aligning reference angle; and switching to the nominal control state wherein the steering wheel aligning reference angle, the left road wheel aligning reference angle, and the right road wheel aligning reference angle are connected to be input signals in the steer-by-wire control system, if the steering wheel aligning reference angle, the left road wheel aligning reference angle, and the right road wheel aligning reference angle is less then the switch threshold for the initial alignment state and nominal control state; wherein the steering wheel aligning reference angle θ s-alg , the left road wheel aligning reference angle θ rl-alg , and the right road wheel aligning reference angle θ rr-alg are given as: whereθ init is a constant to represent the desired alignment angle, θ s and θ s-abs are relative and absolute steering wheel angles, θ rl and θ rl-abs are relative and absolute left road wheel angle, and θ rr and θ rr-abs are relative and absolute right road wheel angle.