Abstract: A method is disclosed for controlling the rear wheel angle in a four-wheel steering vehicle such as a pickup truck. The front wheels are steered using the conventional operator handwheel linked to the front wheels. The rear wheels are actuated with a reversible electric motor and the rear wheel angle controlled using a computer with inputs of vehicle velocity, operator handwheel position and correlated front wheel angle, and handwheel turning rate. Control of rear wheel angle starts with a correlation of ratios of rear wheel angle to front wheel angle, R/F, vs. vehicle velocity suitable, determined under steady state front steering angle and velocity conditions, to maximize the contribution of the rear wheels while avoiding side-slip of the vehicle.

Abstract: A method is disclosed for controlling the rear wheel angle in a four-wheel steering vehicle such as a pickup truck. The front wheels are steered using the conventional operator handwheel linked to the front wheels. The rear wheels are actuated with a reversible electric motor and the rear wheel angle controlled using a computer with inputs of vehicle velocity, operator handwheel position and correlated front wheel angle, and handwheel turning rate. Control of rear wheel angle starts with a correlation of ratios of rear wheel angle to front wheel angle, R/F, vs. vehicle velocity suitable, determined under steady state front steering angle and velocity conditions, to maximize the contribution of the rear wheels while avoiding side-slip of the vehicle.

Abstract: A steering system for an automotive vehicle having two front wheels and two rear wheels is provided.

Abstract: A steer-by-wire system includes a steering wheel; a steering wheel sensor coupled to the steering wheel for sensing the position of the steering wheel and producing a signal indicative of the position of the steering wheel; a controller in signal communication with the steering wheel sensor for receiving the signal indicative of the position of the steering wheel from the steering wheel sensor and producing a signal indicative of a desired steering wheel feedback torque; and a tactile feedback device in signal communication with the controller for receiving the signal indicative of the desired steering wheel feedback torque and providing a corresponding torque to the steering wheel.

Abstract: A method for detecting a loss of motor control in an electric power steering system is disclosed. In an exemplary embodiment, the method includes determining a duty cycle of a steering command signal generated by a controller. The steering command signal commands a steering mechanism to be turned in either a first or a second direction, the second direction being opposite to the first direction. A steering velocity of the steering mechanism is determined, the steering velocity being characterized by a steering velocity magnitude and a steering velocity direction whenever the steering velocity is greater than zero. The steering velocity direction corresponds to either the first or the second direction. The duty cycle is then compared to a first selected value, and the steering velocity magnitude is compared to a second selected value.

Abstract: A rear wheel steering device steers rear wheels of a vehicle by using two electric motors. When the two electric motors are in normal condition, both electric motors are driven to steer the rear wheels. When one electric motor is in an abnormal state while the other electric motor is in a normal state and when a vehicle speed exceeds a given speed, the steering device controls steering of the rear wheels by using only the other electric motor being in normal condition. Since the employed electric motors are small-sized and inexpensive, the rear wheel steering device can be downsized and provided at a relatively low cost.

Abstract: A modular motor and controller assembly for a rear steering system of a motor vehicle includes a motor portion and a controller portion disposed in direct mechanical communication therewith to form a unitary package. The motor portion may include a motor and a motor port, the motor port being configured to provide a communicational interface between the motor and the controller portion. The controller portion may include a controller port configured to be matingly engaged with the motor port. Electronic communication is generally maintained through the controller port and the motor port through a pronged connector.

Abstract: A rear wheel steering apparatus comprises an electric motor for generating a rotational torque, an electric control device for controlling the rotation of the electric motor, a motion converting device for converting the rotational torque of the electric motor into a propulsion force in the direction of a width of a vehicle and connected to a rotational shaft of the electric motor, an output shaft for outputting the propulsion force in the direction of the width of the vehicle which is converted by the motion converting device, tie rods connecting between the output shaft and rear wheels and having a ball joint, respectively, a housing fixed to the vehicle and accommodating the electric motor, the motion converting device and the output shaft therein, a rear wheel steering angle detecting device for detecting a steering angle of the rear wheels steered by the output shaft, a regulating member connected to the housing and for prohibiting the output shaft from rotating while allowing the output shaft to move in

Abstract: A steering system for an automotive vehicle having two front wheels and two rear wheels is provided.

Abstract: Disclosed is a method of swing out compensation in a vehicle with rear wheel steering, comprising: obtaining a zero speed status signal representative of when a vehicle is at zero speed; establishing a rear wheel angle threshold; obtaining a calculated rear wheel angle; and generating a commanded rear wheel angle responsive to the rear wheel angle threshold and the calculated rear wheel angle, whichever is of smaller magnitude.

Abstract: In diagnostic apparatus and method for a motor-driven power-assisted steering system, an abnormality determining section detects a state in which the detected normal/reverse drive current indicates an opposite to a direction of the normal/reverse revolution drive torque and determines whether the state is in excess of a predetermined abnormality determination criterion so as to determine an occurrence in abnormality of the power-assisted steering system, the abnormality determining section comprising a sensitivity reducing section that varies a sensitivity of the abnormality determination criterion in a decrease direction as an absolute value of the detected normal/reverse drive current becomes smaller.

Abstract: In a vehicle attitude control apparatus, a steering actuator is controlled so that a steering angle matches a target steering angle. In an understeer condition; the braking force on the inside wheels is increased and drive power applied to the outside wheels is larger than applied to inside wheels. In an oversteer condition, the braking force on the outside wheels is increased and drive power applied to the inside wheels is larger than applied to outside wheels. The steering actuator is controlled so that a behavior index value corresponding to the change in the vehicle'behavior, that occurs based on the change in the steering angle, matches a target behavior index value that reflects the amount of operation of an operation member. A vehicle yaw moment and an amount of control of the steering actuator vary due to steer conditions, wheel lateral slip angle and brake force control.

Abstract: In a steering device for a vehicle, the movement of a steering actuator driven by operation of an operating member is transmitted to vehicle wheels, in such a manner that the steering angle changes, without the operating member being coupled mechanically to the vehicle wheels. A first target yaw rate is calculated in accordance with the detected vehicle speed and a first steering angle set value, which corresponds to the detected amount of operation and vehicle speed. A second target yaw rate corresponding to the detected lateral acceleration and vehicle speed is calculated. A second steering angle set value, which corresponds to the difference between the detected yaw rate and a target yaw rate, as which the first target yaw rate or the second target yaw rate whichever has the smaller absolute value is taken, is calculated.

Abstract: Controller is designed to control operation of a rear-wheel steering apparatus typically provided in a four-wheel steering vehicle, and is based on electronic circuitry. In the electronic circuitry, a target-steering-angle setting section sets a target steering angle of the rear wheels. Actual-steering-angle measurement section measures an actual steering angle of the rear wheels. On the basis of the target steering angle and actual steering angle, a steering-angle adjustment section generates a motor drive signal to control the rotation of the motor in such a manner that a difference or offset between the target steering angle and the actual steering angle becomes zero. On condition that the motor is in a predetermined driving state, a motor-deceleration-amount calculation section is activated to calculate an actual rotating speed of the motor on the basis of the actual steering angle of the rear wheels and compares the calculated actual rotating speed of the motor with a prestored reference rotation speed.

Abstract: A rear wheel steering apparatus is disclosed which comprises a pair of threaded members which are threaded in a direction opposite to one another, a pair of slide members engaging with the threaded members, respectively, and movable toward and away from one another due to reverse thread action, a steering shaft for steering a pair of rear wheels, and an electric motor for rotating the threaded members to move the steering shaft coupled to one of the slide members toward one of the rear wheels for thereby steering the rear wheels.

Abstract: A closed loop steer by wire control system has three main components, a steering wheel unit, a roadwheel unit, and a master control unit. Signals generated by sensors in the steering wheel unit and roadwheel unit are passed back to the master control unit for processing. These signals include tie-rod force signals, and a steering wheel position signal. The master control unit uses these signals to calculate a steering wheel reaction torque signal which is sent back to the steering wheel unit to provide the operator with tactile feedback, while roadwheel command signals are sent to roadwheel units to provide steering direction. An Ackerman correction unit is also used to correct the left and right roadwheel positions to track about a common center.

Abstract: A device for controlling a turn running behavior of a vehicle detects at least one parameter (V, &ggr;, Gy, Gyh, &ggr;t, &ggr;t−&ggr;) with respect to the turn running behavior in addition to a drive direction of the vehicle, the one parameter being indicative of a higher desirability of the turn running behavior control according to changes of a magnitude thereof, calculates an amount (&Dgr;Ter, Froq, Friq, &Dgr;Tes, Fsop, Fsiq, Fsoq) for the turn running behavior control based upon the detected turn running behavior parameters, determines a start of the turn running behavior control according to the one turn running behavior parameter traversing a threshold value (Vrp, Vrq, &ggr;rp, &ggr;rq, Gyp, Gyq, Gyhp, Gyhq, Vsp, Vsq, &ggr;sp, &ggr;sq, &ggr;tsp, &ggr;tsq, &Dgr;&ggr;p, &Dgr;&ggr;q) determined therefor, and executes the turn running behavior control by operating at least one of the engine and the brake system according to the turn running behavior control amount, wherein threshold value is changed

Abstract: A rear wheel steering device steers rear wheels of a vehicle by using two electric motors. When the two electric motors are in normal condition, both electric motors are driven to steer the rear wheels. When one electric motor is in an abnormal state while the other electric motor is in a normal state and when a vehicle speed exceeds a given speed, the steering device controls steering of the rear wheels by using only the other electric motor being in normal condition. Since the employed electric motors are small-sized and inexpensive, the rear wheel steering device can be downsized and provided at a relatively low cost.

Abstract: A vehicle test apparatus having a rotationally supported steer member and a steer arm assembly including a steer arm operable coupled to the steer member and movable therewith. The steer arm is coupled to the steer member in a first position to form a forward steer arm connectable to a forward steer unit and orientable in a second position to form a rear steer arm connectable to a rear steer unit for front and rear steer testing. A steer actuator is coupled to the steer member and operable between forward and rear actuation modes for forward and rear steer testing.

Abstract: Provided is a rear wheel steering device which includes a rotary shaft having a pair of threaded sections of mutually opposite senses, and a pair of slide members supported in a rotationally fast manner, and having threaded sections which engage the corresponding threaded sections of the rotary shaft so as to be moveable in mutually opposite axial directions as the rotary shaft is turned in either direction, and a pair of clutch units each interposed between a corresponding one of the slide members and the slide shaft for selectively coupling them in an axially fast manner. Thus, the steering direction can be determined by selectively engaging either one of the clutch units, and the magnitude of the steering angle can be determined by turning the rotary shaft with an electric motor in either direction.

Abstract: In an apparatus and method for controlling a yaw rate of an automotive vehicle, a correction of a steering angular sensor detected absolute value of a steering angular displacement of a steering wheel of the vehicle is made by means of a controller by a correction variable for an offset of the neutral steered point to a real neutral steered point by a correction using which the detected absolute value of the steering angular displacement corresponds to the real neutral steered point and indicates zero at the neutral steered point to derive a neutral point corrected steering angle, determination of a target yaw rate of the vehicle on the basis of the neutral point corrected steering angular displacement is made, and a motion of the vehicle as a yaw rate control is controlled so as to achieve the target yaw rate, a determination of whether a variation rate of the neutral point offset correction variable is equal to or above a predetermined variation rate during a predetermined control period is made, and a supp

Abstract: Steering torque sensor detects steering torque manually applied to the vehicle's steering system. Control unit sets a target motor current corresponding at least to the steering torque detected by the steering torque sensor and has a plurality of steering assist modes to which are allocated different characteristics of a target motor current for an assisting motor. The control unit include a mode switching unit that, in response to a mode setting instruction from a vehicle operator, effects a change between the steering assist modes when the steering torque sensor is in its dead zone and no target motor current signal is being generated. Thus, the driver is allowed to continue driving with a steering characteristic fitting his or her preference, and hence good steering feel and vehicle behavior, even when a steering characteristic change takes place during travel of the vehicle.

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 rear-wheel steering system designed to reduce noise to a minimum at a low cost. The rear-wheel steering system includes an electric motor for generating a rotational force, a nut member connected to the electric motor and rotated thereby, and a rod having both ends connected to rear wheels of a vehicle and an external thread portion in mesh with an internal thread portion of the nut member. The rod is axially moved by rotation of the nut member for rear-wheel steering, but is not allowed to rotate. In the system, the internal thread portion is in mesh with the external thread portion such that each axial center is off-center.

Abstract: A steerable drive axle for a motor vehicle including a rigid tubular housing, a pair of steering knuckles at opposite ends of the rigid tubular housing, an expanded chamber in the middle of the rigid tubular housing open on one side for access to a differential gear set in the expanded chamber, a differential cover for closing the open side of the expanded chamber, and an electrically-powered steering apparatus on the cover linked to the steering knuckles. The electrically-powered steering apparatus includes a rack bar passage in the differential cover, a rack bar supported in the rack bar passage for linear translation and linked to the steering knuckles, a pinion head rotatably supported on the differential cover having a pinion gear meshing with a rack gear on the rack bar, an electric motor mounted on the differential cover, and a speed reducer on the differential cover between the pinion head and an output shaft of the electric motor.

Abstract: Disclosed is a method for controlling a rear wheel angle of a four-wheel steering system for a vehicle, including the steps of: setting a control cycle of an actuator; dividing the control cycle into an accelerating section, a uniform velocity section, and a reduction section according to a rotating velocity of the actuator; integrating each section according to the rotating velocity of the actuator; calculating a desired rear wheel angle according to a practical rear wheel angle measured under each integral equation of each section; and executing, during the control cycle, a compensating control with respect to an error value calculated by comparing the practical rear wheel angle and the desired rear wheel angle with each other.

Abstract: The automatic steering device for an electrically controllable hydraulic steering system automatically controls steered wheels (HR) of a steered vehicle, especially an agricultural machine, according to at least one electronic steering control signal (SHL,SHR).

Abstract: A controllable slide car for controllably simulating oversteer and understeer conditions in a moving automobile. The controllable slide car comprises a rear steering linkage assembly that attaches to the rear wheel mounting assemblies of an automobile and a controller for controllably steering the rear steering linkage assembly. The controller is powered by the battery of the automobile and manually controlled by a control unit to steer the rear wheel mounting assemblies.

Abstract: A fail safe device for a rear-wheel steering system prevents an abrupt return of a rear-wheel into a neutral position when the rear-wheel steering system malfunctions during vehicle operation to prevent an overshoot. A rear-wheel is steered by a DC motor according to a vehicle speed. A malfunction sensor senses rear-wheel steering system malfunction. A controller controls a back-electromotive force to be applied to the DC motor. The back-electromotive force is generated by revolution of the DC motor based on a signal which is sensed by the malfunction sensor when the rear-wheel is returned to a neutral position. Switching means applies the back-electromotive force to terminals which are positioned around the DC motor.

Abstract: In a steering control apparatus for an automotive vehicle, there are provided a steering mechanism which is linked with a road wheel to be controlled, an actuator for actuating the steering mechanism, and a steering angle sensor which is arranged in the vicinity of the steering mechanism for detecting a steered position of the road wheel. The apparatus includes a first control circuit which is provided for setting a desired steering angle of the road wheel, and includes a second control circuit which is electrically connected to the first control circuit, and which controls a current to be fed into the actuator in response to a difference between the desired steering angle and an actual steering angle which is produced on the basis of the steered position detected by the steering angle sensor, to control a steering angle of the road wheel. The second control circuit is formed as one body with the steering angle sensor and arranged in the vicinity of the steering mechanism.

Abstract: A control system robust with respect to a vehicle dynamic characteristic variation by a vehicle speed change by estimating an unknown characteristic term in a target yaw rate following system so as to reduce a side slip angle at a transmission time, wherein right and left rear wheels are directly steered using an electric motor controller, and an instruction signal to the motor controller is calculated with a simple calculation using a vehicle speed characteristic estimator with a control amount calculator so that a real yaw rate may follow a target yaw rate calculated by a target yaw rate calculator using respective sensor output values of a vehicle speed sensor, a yaw rate sensor, a steering wheel angle sensor, and a rear wheel steering sensor for each control period.

Abstract: An actuator for effecting a steering action is controlled by a feed-forward variable based on a target steering angle, a state feedback control variable based on an actual steering angle, and an integral control variable given as a sum of an integrated value of a deviation between the target steering angle and the actual steering angle, and an integrated value cancelling variable based on the target steering angle. The integral control variable is disregarded when the detected load is greater than the threshold value. Typically, the integrated value cancelling variable consists of a feedback state variable based on the actual steering angle. Thus, by disregarding the integral control variable in a low speed condition that involves a high load condition but does not require a high tracking capability, the need for the output capacity of the actuator can be substantially reduced without creating substantially any ill effect.