Abstract: In at least some implementations, a method for preventing inadvertant operation of a vehicle access system that includes a plurality of inputs involves providing a keypad operable to output signals to control a vehicle system based on entry of a code via the inputs, detecting when a predetermined access sequence is inputted via the inputs and outputting a signal to a vehicle system to allow access to the vehicle, and operating the keypad in a disabled mode wherein the keypad output signals are not outputted. The disabled mode may be activated either actively or passively or both, and the disabled mode may be terminated either actively or passively or both.

Abstract: In at least some implementations, a shift lever assembly enables shifting among gears of a vehicle transmission. A primary shift path includes multiple positions corresponding to automatic transmission shifting among multiple drive gears, a reverse gear and a park gear. A secondary shift path includes multiple positions to permit user selection among the multiple drive gears, and an interconnecting path extends between the primary shift path and the secondary shift path so that the shift lever may move between the shift paths. A blocking member is movable relative to the shift lever to selectively permit or prevent the shift lever from moving from the primary shift path to the secondary shift path. An actuator moves the blocking member to prevent shift lever movement to the secondary shift path unless the shift lever is in a position corresponding to one of the multiple drive gears.

Abstract: In at least some implementations, a method for preventing inadvertant operation of a vehicle access system that includes a plurality of inputs involves providing a keypad operable to output signals to control a vehicle system based on entry of a code via the inputs, detecting when a predetermined access sequence is inputted via the inputs and outputting a signal to a vehicle system to allow access to the vehicle, and operating the keypad in a disabled mode wherein the keypad output signals are not outputted. The disabled mode may be activated either actively or passively or both, and the disabled mode may be terminated either actively or passively or both.

Abstract: A variable assist power steering system (10) uses both vehicle speed and steering valve inlet pressure to vary the steering assist provided. A system controller (30) receives speed and pressure data from sensors (24, 26) and produces a control signal for an actuator (28) that shunts fluid flow from the pump (22) to the steering valve (20) thereby affecting steering valve pressure which controls the rack piston (16) which changes the angle of the front vehicle wheels used for steering. The controller (30) employs a calibration table (32) with entries representing actuator current, vehicle speed and inlet pressure wherein the speed and pressure fall into ranges defined by equally spaced speed points and equally or unequally spaced pressure points. Having pressure points spaced with a distance between any two sequential points a power of two in sensor counts allows manageable bilinear interpolation of current versus speed and pressure without complicated divide operators.

Abstract: An active suspension system uses a closed-loop feedback controller to with tunable feedback gains to produce a control signal which minimizes a cost function formed by the weighted sum of system outputs including body acceleration and wheel displacement error. The feedback gains are adaptively varied by incremental amounts which are calculated based on the "pseudo-sensitivities" of those gains to system outputs, the pseudo-sensitivities being generated by a fixed-gain model of the suspension system and being combined using weighting factors which insure convergence in accordance with the predetermined cost function. The adaptive control provides long-term compensation for varying road conditions, variations from vehicle-to-vehicle, and changes in vehicle performance.

Abstract: An active suspension system uses a closed-loop feedback controller with tunable feedback gains to produce a control signal which minimizes a cost function formed by the weighted sum of system outputs including body acceleration and wheel displacement error. The feedback gains are adaptively varied by incremental amounts which are calculated based on the "pseudo-sensitivities" of those gains to system outputs, the pseudo-sensitivities being generated by a fixed-gain model of the suspension system and being combined using weighting factors which insure convergence in accordance with the predetermined cost function. The weighting factors are combined with the pseudo-sensitivities in a manner in which the trade-off between body acceleration, wheel displacement error and the control signal is altered with varying magnitudes of road inputs to continually minimize the cost function for varying road inputs.

Abstract: A method and system is provided for improving vehicle handling during vehicle operation in the nonlinear region of the front tires for use with a vehicle (10) having manually operable front steerable wheels (12) and electronically controlled rear steerable wheels (14). The method includes the step of calculating a desired rear steer angle based on vehicle parameters, such as vehicle speed and front wheel angle. Preferably, the method also includes the steps of determining if the vehicle is operating in the nonlinear region of the front tires, calculating a handling term if the vehicle is operating in the nonlinear region of the front tires and modifying the desired rear steer angle based on the handling term. The rear steerable wheels are then steered toward the modified desired rear steer angle.

Abstract: A self-tuning speed control system is disclosed. The gain of the system controller is tuned to provide optimal performance based upon a sensitivity point analysis and gradient optimization of a prescribed cost index.