Abstract: A variable toe angle control system for a vehicle that can be incorporated with a fail-safe mechanism. When a fault of the system is detected, at least one of toe-angle actuators is actuated to make toe angles of two wheels agree with each other. When one of the wheels has become fixed in position without regard to a control signal supplied to the corresponding actuator, the actuator for the other wheel is actuated so as to make the toe angles of the two wheels equal to each other. When at least one toe-angle sensor is found faulty, the actuators are both actuated until the actuators reach positions corresponding to stoppers. When information for determining target values of the toe angles of the right and left wheels is found faulty, the actuators are both actuated until the actuators reach positions corresponding to prescribed reference toe positions.

Abstract: A method and system for predicting a future position of a horizon time Th of an automotive vehicle. The method determines the position of the vehicle at time T0 using GPS and the speed, acceleration and angle of the steering wheel at time T0 from appropriate sensors on the vehicle. A nonlinear mathematical model utilizing these factors is then created while the position of the vehicle at time T0+Th is determined through numerical integration of the mathematical model using an adjustable step size Tstep. The step Tstep is modified adaptively in accordance with the accuracy requirements of the vehicle.

Abstract: A controller for a vehicle including at least one motor driving wheels, an inverter driving the motor, and a boosting converter supplying a dc power supply current to the inverter, is provided with a control portion performing rectangular wave control and non-rectangular wave control on the inverter in a switched manner. The control portion has an emergency switching condition for switching control from the rectangular wave control to the non-rectangular wave control, as a determination reference, and when the emergency switching condition is satisfied while the rectangular wave control is being executed (YES at step S5), the control portion instructs the boosting converter to lower target output voltage (S7). Preferably, the control portion determines that the emergency switching condition is satisfied when a q-axis current supplied from the inverter to the motor exceeds a prescribed threshold value.

Abstract: A vehicle steering apparatus for improving steering feel when changing the angle of a steered wheel with a motor. An IFS torque compensation unit includes an oversteer IFS torque compensation gain calculation unit, which obtains a larger IFS torque compensation gain as a control target element increases during oversteer control. When an oversteer state occurs, the IFS torque compensation control unit outputs a corrected gain, which is based on the IFS torque compensation gain.

Abstract: A torque control element for a steering system in a motor vehicle, and such a steering system are provided. The torque control element includes at least two electrical units, each of the electrical units being assigned a separate power supply unit, connected via at least one fuse.

Abstract: An electric power steering device that can estimate an ambient temperature and apply current limiting without using ambient temperature detecting means is provided. The electric power steering device includes a motor that supplements the driver's steering force, a controller that determines and controls the quantity of current passed to the motor, and vehicle speed detecting means. The electric power steering device includes ambient temperature estimating means provided with a vehicle speed signal input from the vehicle speed detecting means and limits the quantity of current passed to the motor according to an output from the ambient temperature estimating means.

Abstract: An apparatus (10) for turning steerable wheels (12, 14) of a vehicle in response to turning of a steering wheel (18) of the vehicle. The apparatus includes a hydraulic power steering gear, which does not include a rotary valve responsive to a steering input generated by turning of a steering wheel (18). The hydraulic steering gear includes a first chamber (96) for holding hydraulic fluid and a second chamber (98) for holding hydraulic fluid. An increase in fluid pressure in one chamber acts to turn the steerable wheels (12, 14) of the vehicle in one direction and an increase in fluid pressure in the other chamber acts to turn the steerable wheels (12, 14) in a direction opposite the one direction. The apparatus (10) includes a variable flow mechanism (50) for supplying a flow of hydraulic fluid to the first and second chambers (96, 98), which flow varies in dependence upon at least one sensed vehicle condition.

Abstract: In a power steering device employing a hydraulic power cylinder, a motor-driven pump, and a driving power source for the motor, a power steering control system is configured to electrically connected to at least the motor and the power source for controlling a driving state of the motor and a power source voltage of the power source. The power steering control system includes a motor control circuit that generates a motor driving signal, whose command signal value is determined based on a steering assist force applied through the power cylinder to steered road wheels, a booster circuit that boosts the power source voltage, a motor angular acceleration detection circuit that detects or estimates a motor angular acceleration, and a booster-circuit control circuit that controls, responsively to the motor angular acceleration, switching between operating and non-operating states of the booster circuit.

Abstract: A method of controlling a magneto-rheological power steering coupling is provided. The method is to be employed by a controller and is initiated upon engine start-up. The method includes initializing calibration parameters and reading a plurality of input values. Subsequently, a hand wheel angle rate value is calculated from one of said plurality of input values. A pump speed command value is calculated as a function of at least the hand wheel angle rate value. A pump speed error value is then calculated, and a proportional-integral-derivative calculation is performed acting on the pump speed error value to determine a pulse width modulation duty cycle value. The duty cycle value is then output to a power driver to provide a control signal to the magneto-rheological power steering coupling. Also provided is control system and apparatus operable to perform the functions described hereinabove.

Abstract: The invention relates to a device for controlling the steering of a commercial vehicle comprising: two front wheels (126, 127) that can be oriented according to a first turning angle by means of at least one first actuator (120); two rear wheels (136, 137) that can be oriented according to a second turning angle by means of at least one second actuator (130); and a power circuit (101) comprising a pressurised fluid source and power components (111, 112, 113, 114, 115) that can transmit the hydraulic power to the actuators, said power components (111, 112, 113, 114, 115) being controllable in such away as to configure the power circuit (101) according to different coupling modes between the front wheels (126, 127) and the rear wheels (136, 137).

Abstract: The invention generally relates to an improvement of conventional Hydraulically Power Assisted Steering system (HPAS-system) arranged to supply a steering assist force to the steering assembly of a vehicle as a response to a torque applied by a driver to the steering wheel. In such HPAS-systems a certain drivers torque always results in a certain assist force. The invention therefore discloses a valve that can be actuated to dynamically alter the steering assist force produced by the HPAS-system. This makes it possible to dynamically adjust the assist force so that an appropriate force may be delivered to fit the specific driving scenario.

Abstract: The invention relates to a method for motor vehicles provided with an electrical sero steering controlled by an electronic processor. The method comprises using an electrical signal within the processor which has at least one component image of the parasite vibrations coming from the front subframe. Said signal is filtered such as to isolate the component image of the parasite vibrations, from which a corrective value for the control current, which controls the electric servo motor for the steering, is calculated. The corrective value thus calculated is subtracted from the current control, determined by taking into account other parameters, to give a corrected control current, which gives to rise to an attenuation in the vibrations transmitted to the steering system and the steering wheel by acting on the servo steering.

Abstract: An electrically actuated, hydraulic power steering system is provided. The steering system includes a hydraulic pump for generating hydraulic pressure, a hydraulic fluid reservoir, a hydraulic cylinder, and a control valve arrangement that selectively connects the hydraulic cylinder to the pump and the hydraulic fluid reservoir. The control valve arrangement is characterized during the on-center position by a first and a second chamber of the hydraulic cylinder being in fluid communication with each other but not with the fluid reservoir. In one embodiment, the steering system has a steering sensor, a control box, and two pressure accumulators for providing at least two levels of steering assist.

Abstract: Methods and apparatus for steering a vehicle are disclosed. A vehicle in accordance with an exemplary embodiment of the present invention is capable of operating in a first steering mode and a second steering mode. The vehicle may comprise an input device capable of providing an input signal indicating that operation in the second steering mode is desired. The vehicle may comprise an electronic control unit (ECU) capable of providing an enabling signal when the ECU determines that operation in the second steering mode is appropriate for the present riding conditions.

Abstract: In a steering mechanism for a motor vehicle having a steering wheel with a steering shaft connected to a steering gear arrangement, the steering shaft comprises a first vibration damping element for accommodating and attenuating vibrations with relatively low amplitudes as they are generated by uneven road surfaces and a second element having lower damping characteristics than the first element for the transmission of steering movements from the steering wheel to the steering gear arrangement.

Abstract: Operates steering angular velocity in first steering angular velocity calculating unit and second steering angular velocity calculating unit, by using steering angle signal from steering angle generating unit, and outputs steering angular velocity by switching them with reference to a certain threshold value of steering angular velocity.

Abstract: A rear steer control for a motor vehicle considers vehicle velocity in three ranges and provides an out of phase rear steer angle in open loop control within a low velocity range for oversteer assistance of parking and similar vehicle maneuvers, an in phase rear steer angle in closed loop control responsive to vehicle yaw rate within a high velocity range for understeer vehicle stability assistance, and a steer angle in closed loop control responsive to vehicle yaw rate within an intermediate velocity range. In a preferred embodiment, the closed loop control in the high velocity range may be combined with an open loop control. The control further provides supplemental throttle adjustments in coordination with the rear steer control for increased traction and stability in a turn.

Abstract: During ordinary travel, a direction change cylinder (51) is actuated by an orbit roll (58) by turning a steering wheel (16) right and left, so that the rear wheels (4) can be turned for direction change in response to the operation of the steering wheel. When the direction change cylinder is actuated to the limit, the right and left rear wheels can be turned for direction change into an inclined state with their rear ends approaching each other, thereby making it possible to make a pivot turn. The front and rear wheel turning devices (30, 50) are actuated to turn the front wheels (3) and rear wheels around vertical axes (27, 49) for direction change by 90 degrees (directed exactly sideways). At this time, in the rear wheel turning device, with the direction change cylinder put in the neutral position, the rear wheel transverse travel cylinders (53) are actuated to turn the rear wheels for direction change by 90 degrees.

Abstract: A rotational angle detecting apparatus having a rotation detector that outputs, as a rotor coupled to a rotating member rotates, first and second detection signals, which have predetermined amplitudes, the same cycle, and a phase difference of a quarter wavelength, a memory for storing the first and second detection signals, and a control unit. The control unit detects the rotational angle of the rotating member by averaging the amplitudes of the first and second detection signals according to the area in which the first detection signal lies.

Abstract: A fuzzy steering controller for wheel-type agricultural vehicles with an electrohydraulic steering system is disclosed. The fuzzy controller was developed based on a common-sense model of agricultural vehicle steering. The controller implements steering corrections based upon the desired steering rate and the error between the desired and the actual wheel angles. The controller consists of a variable fuzzifier, an inference engine with a steering control rulebase, and a control signal defuzzifier. The controller could be used on different platforms. Tuning of the fuzzy membership functions will accommodate for physical differences between the platforms. The controller achieves prompt and accurate steering control performance on both a hardware-in-the-loop electrohydraulic steering simulator and on an agricultural tractor.

Abstract: The invention relates to a hydraulically assisted steering system for a motor vehicle. Because there is associated with the hydraulic system an electromechanical valve 12 which, in the open state, hydraulically indirectly or directly connects the working chambers 3 , 4, it is possible to dispense with conventional mechanical pressure limiting valves, secondary suction valves and limit stop valves.

Abstract: A multiple-axle steering system for an agricultural machine with at least one primary-controlled axle and at least one secondary axle, where the latter's steering deflection angle varies along a progressive characteristic curve as a function of the primary-controlled axle's steering deflection angle. The variation in steering deflection angle along the progressive characteristic curve means that the steering deflection angle of the primary-controlled axle in a range around the zero or neutral position initially results in only a slight steering deflection of the secondary axle. As the steering deflection of the primary-controlled axle increases, the steering deflection angle of the secondary axle progressively approaches the steering deflection angle of the primary-controlled axle. When using all-wheel steering, the use of the progressive characteristic curve facilitates smooth steering when driving on the road, where usually minimal steering deflection is performed by the machine operator.

Abstract: A system provides feedback to an operator of a steer-by-wire system. In steer-by-wire systems, there is no direct mechanical connection between the vehicle steering wheel and the steering gears. The present invention utilizes a sensor to sense torque values at the steering gears. The sensor communicates signals back to the steering wheel as operator feedback. The sensed and communicated torque values include high frequency torque fluctuations to provide road-feel in steer-by-wire systems. Also, the torque can be used to make predictions of the operator's conditions and the condition of the steering system.

Abstract: A full fluid-linked steering system, especially for use in on-highway steering, in which the system includes a fluid controller (21) including a fluid meter (65) operable to provide follow-up movement to controller valving (87,89), in response to the flow of fluid through the meter. The controller (21) includes a centering or biasing spring assembly (75) which provides sufficient torque that, upon rotation of the steering wheel (W), fluid is communicated to the steering actuator (19) without relative displacement of the valving, thus providing driver with the desired road feel. The system includes an EHC valve assembly (23) which controls flow to or from the actuator (19) in response to appropriate input signals (113,115) to maintain steered wheel to steering wheel registry.

Abstract: In a method for controlling a rear wheel steering device of a front and rear wheel steering vehicle, the target computed rear wheel steering angle is defined as a value smaller than the normal computed target rear wheel steering angle when the load of the steering actuator is greater than a prescribed threshold value, and which is otherwise equal to the normal computed target rear wheel steering angle, and the steering actuator is actuated according to a deviation of the actual rear wheel steering angle from the modified computed target rear wheel steering angle, typically with a duty ratio control. Thus, the rear wheel steering device can be operated in a satisfactory manner even when the output capacity of the actuator for the rear wheel steering device is limited, and the steering load is high. A high load condition typically occurs when the vehicle is stationary and when the steering wheel is turned sharply while the vehicle is traveling over a road surface having a high frictional coefficient.

Abstract: A vehicle steering system includes a first steering mechanism for a manual steering mode and a second steering mechanism for an automatic steering mode. A controller steers the vehicle in accordance with information on driving environment, with the second steering mechanism when the automatic mode is selected with a mode selector. There is further provided a holding device for holding the steering angle of the first steering mechanism when the automatic steering operation of the second steering mechanism is under way. In response to selection of the automatic mode, the controller performs the automatic steering control only when a sensor senses a straightforward neutral position of the first steering mechanism.

Abstract: The invention relates to a steering angle adjusting device with an operating element for adjusting the steering angle as a function of a corresponding operating element actuating parameter. According to the invention, steering angle adjustment takes place as a function of the operating element actuating parameter with a sensitivity that decreases with decreasing coefficient of friction and/or the maximum adjustable value of the operating element actuating value decreases with a decreasing coefficient of friction and/or an increasing lengthwise speed of the vehicle.

Abstract: A hydrostatic power steering system comprising a fluid motor (19) which receives pressurized fluid from a controller (17) in response to the rotation of a vehicle steering wheel (W). As the motor (19) or the steered wheels reach the stops, control logic (31) receives signals (37,77) representing steered wheel and steering wheel position, respectively, and generates appropriate command signals (33,27) to a pressure reducing/relieving valve (15) and to a proportional electromagnetic valve (23), respectively, closing the valve (15) somewhat, and opening the valve (23). A pressure differential is built between an additional fluid path (21) and the high pressure conduit (15c) between the controller (17) and the fluid motor (19). Pressure is communicated through the valve (23) into the conduit (51c), and back into the fluid meter (43) of the controller, preventing any further rotation thereof in response to an attempt to turn the steering wheel, thus eliminating travel limit slip.

Abstract: The invention relates to a hydraulic power steering system for motor vehicles, in the case of which the manual steering wheel is normally connected only by way of a control system with respect to the drive with a servomotor operating the steered vehicle wheels. In the event of a malfunctioning of the control system, a hydraulic forced coupling is automatically established between the servomotor and a hydraulic delivery unit which is constantly forcibly coupled with the steering handle, in order to form a "hydraulic linkage".

Abstract: The present invention relates to a method for steering a vehicle (1) with steerable front and rear wheels (2, 3), in which the angle (.beta.) of the rear wheels (3) is set as a function of the steering angle (.alpha.) of the front wheels (2) and other parameters. The displacement of the rear wheels (3) during start-up and steering out of forward travel follows the steering movement of the front wheels (2) with a time delay. Such a steering characteristic prevents a corner (5) of the rear of the vehicle which is on the outside of the turn from running over a laterally placed obstacle, for example a curb, when starting up.

Abstract: A vehicle steering angle control device which accurately guides a vehicle along a predetermined drive course by accurately controlling a steering angle of the vehicle based on a degree of curvature of a curved course on which the vehicle is currently running and a current speed of the vehicle in which the degree of curvature of the curved course on which the vehicle is currently running is determined by calculating a degree of deviation of the vehicle relative to a vehicle advancing direction corresponding to current vehicle advancing direction data or an integration of the degree of deviation and a current speed of the vehicle is detected; a steering angle suitable for the degree of curvature of the curved course and the current speed of the vehicle is found and the steering angle of the vehicle is controlled to realize the suitable steering angle, whereby the vehicle is guided along the predetermined driving course.

Abstract: The present invention relates to a steering system for the rear wheels (13,14) of a vehicle comprising an actuator (18) for steering the rear wheels (13,14), sensor unit for measuring vehicular parameters (e.g. a vehicle speed sensor (20), an accelerometer (21) and a steer angle sensor (23)) and generating signals indicative thereof, and a control system for controlling the actuator (18) comprising a processor (17) which processes the signals generated by the sensor unit (20,21,23) and controls the rear wheels (13,14) accordingly. The control system of the invention has detection unit to detect when the signals generated by the sensor unit (20,21,23) indicate that the vehicle is sliding and override unit which modifies the operation of the control system when sliding is detected.

Abstract: A four-wheel steering system for a vehicle including a front wheel Steering part having a front direction control valve having ports which close and open in accordance with a rotating direction of a steering wheel, and a front actuator for pushing or pulling a tie rod connected to a front wheel, an electronic control unit for controlling a steering of the rear wheels in response to signals transmitted from a vehicle speed sensor, a steering angle sensor and a steering amount feedback sensor, and a rear wheel steering part having first and second solenoid valves independently controlled by said electronic control, first and second rear direction control valves independently controlled by said electronic control unit and first and second rear wheel actuators for pulling or pushing said rear wheels selectively or simultaneously.

Abstract: A full-time all wheel steering system is provided whereby the rear wheel angle is determined by the front wheel angle and a relational curve, polynomial equation or set of tabulated values. The front wheel angle is measured and the desired rear wheel angle is calculated by a programmable controller. If the desired rear wheel angle is not sufficiently close to the actual rear wheel angle, the controller means sends a signal which results in adjustment of the rear wheel angle. The desired rear wheel angle may be a function of the vehicle speed as well as the front wheel angle. A dead band may be employed which maintains the rear wheels in a straight ahead position when the front wheel angle does not exceed the dead band value. The maximum rear wheel cramp angle may also be controlled as a function of vehicle speed. The system is applicable to passenger cars, trucks and tractor-trailer rigs.

Abstract: A process for steering a road vehicle having all wheel steering for placing the vehicle into, within, and out of constricted spaces and small, constricted travel areas, the vehicle having a front, a rear, a longitudinal axis, front wheels steerable rear wheels, the all wheel steering being proportional between the front and rear wheels for turning the vehicle about a turning radius, apparatus for determining the distance of the vehicle from an obstacle, and apparatus for restricting or disabling the steerability of the rear wheels in response to the proximity of the obstacle, by driving the vehicle to the proximity of the obstacle, determining the distance of the vehicle from a location on the obstacle when the vehicle approaches the obstacle closer than by a predetermined distance, determining the relative angle of the longitudinal axis to the location on the obstacle, and adjusting the steering of the rear wheels in response to changes in the angular position to move the vehicle along the obstacle without t

Abstract: A vehicle yaw control for a vehicle having wheel brakes wherein the wheel brakes complement driver controlled steering efforts by establishing a maximum steering angle that can be used for any given coefficient of friction at the wheel-road interface and for any given speed, thereby achieving optimum lateral control during turning maneuvers by compensating for under-steering and over-steering for each driving condition.

Abstract: A vehicular brake booster using fluid pressurized by a hydraulic power steering system hydraulic pump. Fluid pressure is controlled by using a pressure regulator in the pump output and by electronically switching fixed orifices in a boost developing valve controlling fluid flow within the power steering system. Additional control is effected by electronically opening and closing apply and relief valves controlling fluid flow respectively to and from a brake power booster for differing periods.

Abstract: A vehicle has a steering control system including a first mode in which the front and rear steering mechanisms operate and a second mode in which only the front steering mechanism operates. When the control system is switched from the first mode to the second mode by a master switch, the change to the second mode is prevented unless and until the rear steering mechanism is in a straight-ahead condition. This condition is sensed by an alignment sensor which is activated by the switching of the master switch to the state corresponding to the second mode.

Abstract: Many known all wheel steer arrangements suffer from the problem that the front and rear wheels getting out of synchronization due to leakage and/or inadvertent passing of fluid across the control valve arrangement therein. In the subject invention, a hydraulic system has front and rear pairs of steerable wheels respectively interconnected by first and second fluid cylinder arrangements. A steering control arrangement operatively controls the front and rear pairs of steerable wheels between a mode in which only the front pair of wheels are steered, a second mode in which both the front and rear pairs of wheels are simultaneously steered but in opposite directions, and a third mode in which the rear wheels are steered independently of the front pair of wheels.