Abstract: A vehicle steering system coupled to a steerable wheel, comprising a steering rack linked to said steerable wheel, an electric motor having an output shaft engaged with the steering rack for controlling the steerable wheel. The system also includes a position sensor configured to measure an actual steerable wheel angle of the steering rack and thereby the steerable wheel, a return spring, where the return spring is biased so as to provide a returning force to the steering rack. Finally, the system includes a controller that provides a command to the electric motor resulting in a torque, the command is responsive to the actual steerable wheel angle, a desired steerable wheel angle, and a command direction.

Abstract: A method of compensating for errors in the measurement of the kinematic properties of an electric power steering motor for an automobile is disclosed. The method comprises generating a set of M-ary signals; measuring the pulse width of the set of M-ary signals; and measuring the time between the edges of the set of M-ary signals. The motor velocity may be directly measured by a tachometer or other such device. The motor position signal can be used to estimate the angular velocity of the motor, by determining the change in angular position of the motor divided by the change in time.

Abstract: The invention is directed to a method and an arrangement for controlling a vehicle and for providing data to the driver as to a tire pressure loss. When a tire pressure loss is detected, a limit speed is pregiven to which the speed of the vehicle is limited. The limit speed is dependent upon the distance already traveled since occurrence of the pressure loss or the elapsed operating time. Furthermore, for a detected tire pressure loss, the maximum range or the maximum operating time of the vehicle having a tire with reduced air pressure is determined and this is displayed to the driver.

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. dolly wheel steering system includes a dolly wheel, a dolly wheel spindle in communication with the dolly wheel such that the dolly wheel and the dolly wheel spindle are fixedly secured to one another and are rotatable as a single unit. The dolly wheel spindle is in communication with a coupling device and a steering control system. The steering control system and the coupling device are each in communication with a controller to regulate actuation of each. When a signal from the controller requests utilization of steering control, the coupling device applies a restraining force to the dolly wheel spindle to limit free rotation of the dolly wheel. When the rotation of the dolly wheel spindle is thus restrained, the steering control system can effectuate direct steering control of the dolly wheels to provide precise directional control.

Abstract: An electric power steering apparatus for a vehicle includes a rack shaft having a rack of gear teeth formed at one end portion thereof and an externally threaded screw formed at a portion thereof excluding the toothed one end portion, a pinion meshing with the rack, a ball-screw mechanism having a nut threadedly engaged with the screw via balls, and an electric motor having a hollow motor shaft extending around the rack shaft and connected to the nut such that an assist torque generated by the electric motor is transmitted from the motor shaft via the nut to the rack shaft. The nut is disposed between the rack and the electric motor. This arrangement ensures that the electric motor and the electric power steering apparatus can be assembled easily and efficiently.

Abstract: A device and method for transferring steering responsibility from a first electro-mechanical actuator to a second electro-mechanical actuator comprises a cylinder and a first piston slideably disposed within the cylinder. A second piston is slideably disposed within an interior chamber of the first piston. A first locking sleeve is disposed within the interior chamber, a second locking sleeve is disposed within the interior chamber in opposition to the first locking sleeve, a first spring is disposed within the interior chamber interposed between the first locking sleeve and the first piston, and a second spring is disposed within the interior chamber interposed between the second locking sleeve and the first piston. The pistons and the locking sleeves also each include at least one groove disposed therein. Snap rings may be disposed within the grooves. A damping mechanism may also be incorporated into the structure of the device.

Abstract: An electric power steering apparatus including a reduction mechanism 5 for transmitting an output of a steering assist motor 1 to a steering mechanism through a worm 3 and a worm wheel 4, in which the worm wheel 4 is formed by a thermosetting synthetic resin filled with a sheet 6 of aramid fibers having a low attacking property to a counter member and an effect of improving the abrasion resistance of the synthetic resin. Even when the reduction mechanism is used in an engine room or the temperature of the reduction mechanism is raised by frictional heat with heightening power, the reduction mechanism is durable, and further the gears have excellent abrasion resistance and toughness and improved durability.

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 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: An automatic steering system for a vehicle is provided which includes a memory section for storing data for a steering angle of a wheel with respect to a distance of movement of a vehicle in correspondence to four parking modes. If a desired parking mode is selected by a mode selecting switch and the vehicle is moved at a creep while depressing a brake pedal, a control section controls the operation of a steering actuator to perform automatic parking control. At this time, an object detector continuously detects the position of an object around or in the vicinity of the subject vehicle, and when there is an obstacle already existing within a locus of movement of the subject vehicle, or when there is a possibility that a moving obstacle may enter into the locus of movement of the subject vehicle, a warning is provided to a driver, and an automatic brake is operated. Thus, it is possible to reliably perform the automatic parking control when there is an obstacle.

Abstract: A method for detecting an erroneous travel direction or a defective yaw rate sensor 12 is disclosed. Two estimates of the vehicle yaw rate are gathered from separate criteria and are compared with one another as well as the measured vehicle yaw rate. Using these comparisons along with other information regarding vehicle travel, a conclusion of whether a travel direction signal is erroneous is made. This determination can then be used to modify the vehicle's brake control strategy.

Abstract: An electric power steering control system reducing steering torque without making a driver feel uncomfortable torque oscillation, including a rotation speed observer for estimating the rotation speed of a motor based on the output of a torque sensor high pass filter (HPF) and the output of a drive current HPF obtained by removing a steering frequency component from a drive current detection value.

Abstract: The system for guided steering of a set of rear wheels of a semi-trailer comprises a pulling vehicle and a semi-trailer having rear wheels which are turnable with respect to a chassis of the trailer to turn from a neutral position to one or the other side of the semi-trailer for generating steering of the vehicle in one direction with respect to a neutral position. The system further comprises power generating apparatus to act on the rear wheels to generate turnings of the rear wheels, activating apparatus mounted in the driver's cabin of the vehicle for operation by the driver of the vehicle for generating a steering of the rear wheels independently of the steering of the vehicle as well as locking structure operated from the driver's cabin, in a first position for generating locking of the rear wheels in the neutral position, and switchable from the first position to a second position, where the rear wheels are released and brought to turn by activation of the activating apparatus.

Abstract: An electric power steering control for a motor vehicle reduces motor torque ripple and road generated disturbances communicated to the vehicle handwheel while promoting system stability. In deriving an output command torque signal to the EPS motor, the control (1) derives an electric motor speed signal, (2) differentiates the electric motor speed signal, (3) stores a schedule of gain as an increasing function of electric motor torque, (4) modifies the differentiated estimated electric motor speed signal in response to the gain to provide a damping correction value and (5) derives the output command signal responsive to the damping correction.

Abstract: A power steering apparatus for an electric vehicle has a steering mechanism for steering a pair of steered wheels upon receiving assist power from a steering assist-power according to a steer force required for steering the steered wheels. A fluid pressure pump driven by an electric motor supplies pressurized fluid to the steering assist-power mechanism. An electric motor controller stops the electric motor when the electric-source voltage detected by an electric source voltage detector is greater than or equal to a voltage set value and when the steer angle detected by a steer angle detector is smaller than a steer angle set value, and prohibits stopping the electric motor when the electric-source voltage is smaller than the voltage set value. Therefore, it becomes possible to ensure the steering responsiveness under an electric voltage lowered condition while avoiding the disturbance to the electric source.

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: Controller for an electric power steering system, which is adapted to predict a drop in power supply voltage for a motor and to perform an idling-up operation when the drop in the power supply voltage is predicted. Namely, this controller for the electric power steering system is adapted to control the motor for giving a steering assist force to a steering mechanism according to a current control value calculated from a steering assist command value, which is computed according to steering torque generated in a steering shaft, and from a motor current value. Further, this controller is provided with a predicting unit for predicting an occurrence of the drop in power supply voltage to be applied to the motor. Moreover, an idling-up operation is performed when the drop in power supply voltage is predicted.

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: An apparatus for controlling a motion of a vehicle supported on steered and non-steered road wheels. A target vehicle motion value is calculated based on the steering angle and vehicle speed to provide a predetermined response characteristic related to a vehicle plane behavior. A target steering angle value for the non-steered road wheel to realize the vehicle plane behavior is calculated according to the target vehicle motion value. The non-steered road wheels are steered according to the calculated target steering angle value. The damping characteristic of the response characteristic is decreased as the vehicle speed increases.

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: A shaft position indicator in which a collar is formed on and moves on in accordance with a shaft. The collar is placed opposite an optical sensor and includes a notch which activates an optical sensor when the notch is located opposite the sensor. When the notch is opposite the sensor, a driving circuit outputs a voltage. When the notch is not opposite the sensor, the driving circuit outputs 0 voltage. The light source and sensor are placed a distance from the collar equal to the focal length to substantially eliminate interference from ambient light.

Abstract: Provided is a counter-steer condition detecting device which is suited to be used in combination with steering control systems based on the control of the magnitude of the effort required for the vehicle operator to steer the vehicle depending on the behavior of the vehicle. An over-steer condition may be detected by evaluating the signs of the current and previous values of the steering angle and the steering angular speed, and the magnitude of the steering angular speed when the steering angle passes a certain monitor level.

Abstract: An electric power steering control apparatus is intended to improve the convergence and control stability of a returning motion of a steering wheel when a driver of a vehicle on which the apparatus is installed lets his or her hands free from the steering wheel, and to reduce a burden to the driver when an excessive steering torque occurs during the returning motion. The apparatus includes a steering torque sensor 8 for detecting a steering torque of a steering system of the vehicle, a motor rotational-speed detector 7 for detecting a rotational speed of the electric motor, and a rotational-speed controller for controlling the electric motor based on output signals from the steering torque sensor and the motor rotational-speed sensor so that when the steering torque as detected is less than a predetermined torque value, the rotational speed of the electric motor does not exceed a predetermined speed value corresponding to the predetermined torque value.

Abstract: An electric power steering apparatus for recovering a steering wheel to its neutral position based on the speeds of the steered wheels of a vehicle. In response to a steering torque signal from a torque sensor, assisting torque by a motor is controlled in a torque servo system from a phase compensating filter to a current detecting unit. A microcomputer calculates a speed ratio of left and right wheels based on wheel speeds detected by wheel speed sensors. Recovery compensating torque is obtained from the speed ratio of the left and right wheels, and a corresponding signal is output to an addition calculating unit. The addition calculating unit adds the steering torque signal and the signal representing the recovery compensating torque to obtain a recovery compensated signal. Based on the recovery compensated signal, the assisting torque is controlled to recover the steering to its neutral position.

Abstract: An omnibus with steered front wheels as well as steered and driven rear wheels, the rear wheels being arranged in the region of a rear end of the omnibus such that wheel housings associated with the rear wheels are arranged essentially at the rear end and/or outside the passenger compartment. A particularly compact and economical drive is obtained due to fact that the drive for the rear wheels comprises an electric drive, wherein the rear wheels are driven by wheel hub motors free of slip and the wheel hub motors are designed as electric motors.

Abstract: A vehicle attitude control device including a yaw moment control mechanism for giving a yaw moment to the vehicle and controlling the yaw moment, and a controller for controlling the yaw moment control mechanism in a normal target follow-up control mode so that the actual yaw rate detected by a yaw rate sensor coincides with a target value determined on the basis of an angle of rotation of a steering wheel detected by a steering wheel angle sensor, and wherein a yaw moment reducing device is provided for reducing the yaw moment to be given to the vehicle by the yaw moment control mechanism, to a reduced value smaller than a normal value to which the yaw moment is controlled in the normal target follow-up control mode.

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: 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: 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 method for determining a center position of a vehicle steering system, said method comprising the steps of reading a plurality of predetermined inputs. The method includes the steps of roughly estimating a center position of the vehicle steering system after the vehicle begins moving based upon the read predetermined inputs and determining whether the steering wheel of the vehicle steering system is approximately straight. The method further includes the steps of accurately estimating a center position of the vehicle steering system if the steering wheel of the vehicle steering system is approximately straight and concluding that the accurately estimated center position is the center position of the vehicle steering system if the steering wheel of the vehicle steering system is approximately straight and Concluding that the roughly estimated center position is the center position of the vehicle steering system if the steering wheel of the vehicle steering system is not approximately straight.

Abstract: In a control device for an electric actuator of a steering system of a vehicle, the amount of power assist provided by the electric actuator of the steering system is appropriately diminished when the steering wheel is turned more than appropriate under the given road condition so that the effort to turn the steering wheel may not be excessively reduced even on a slippery road surface. Thus, when the vehicle is steered more than appropriate for a given road condition, the steering effort is increased by reducing the power assist of the steering system, whereby the vehicle operator is prevented from excessively steering the vehicle. This increase in the steering effort occurs only when the vehicle operator attempts to increase the steering angle, and does not affect the tendency of the steering wheel to return to its neutral position.

Abstract: In an electric power steering system in which a torque assist command is generated for controlling a motor that provides electric power assist torque at a desired torque, a method of motor control according to the steps of: determining a voltage mode motor command responsive to the torque assist command, wherein the voltage mode motor command commands a first motor torque that is (a) greater than the desired torque when the desired torque is low and (b) substantially equal to the desired torque when the desired torque is high; determining a current mode motor command responsive to the torque assist command, wherein the current mode motor command commands a second motor torque that is (a) substantially equal to the desired torque when the desired torque is low and (b) greater than the desired torque when the desired torque is high; and controlling the motor responsive to the voltage and current mode motor commands, wherein the motor assist torque is equal to a lesser of the first and second motor torques.

Abstract: An electric power steering system is disclosed which includes an electric motor adapted to supply steering assist directly to the steering system to thereby reduce the steering torque to be exerted to the system by a driver. The steering system includes a phase compensative device which is formed of a phase delay circuit, or the phase delay circuit and a low-pass filter connected in series thereto, and is positioned in a loop connecting a motor current detector in the steering system and a drive controller in a control block, so that high-frequency components may be removed from motor current signals in the feedback loop. As a result, it is possible to suppress lag of the phases of the signals and hence to prevent parasitic oscillations, leading to the steering system being capable of providing steering assist most suited to particular steering operations and comfortable steering feel to a driver.

Abstract: A steering angle control apparatus for controlling steering angles of front wheels and rear wheels of a vehicle includes a yaw rate detector for detecting an actual yaw rate of the vehicle. A desired yaw rate calculator estimates a desired yaw rate for causing the vehicle to drive stably. A yaw rate disturbance calculator calculates a yaw rate disturbance which causes the detected yaw rate to deviate from an ideal yaw rate of the vehicle assuming driving in ideal driving conditions. A desired yaw rate compensator compensates the desired yaw rate based on the calculated yaw rate disturbance and produces a compensated yaw rate so that the desired yaw rate tracks the compensated yaw rate.

Abstract: The present invention provides an electric power steering apparatus in which it is decided whether or not steering torque is in a predetermined drive inhibition area, and when the term in which the decision result is logically inconsistent with driving instruction for the motor in accordance with the steering torque is shorter than a predetermined period of time, a timer is reset to drive the motor. As a result, the compensation of the inertia of said motor can be controlled even when the steering torque is small. Further, in the electric power steering apparatus, the timer is also reset to drive the motor when the steering torque is in a dead zone and a driving current for the motor is smaller than a predetermined value. As a result, the drive of the motor can be controlled also when a steering wheel is returned to its initial position.

Abstract: An electrically assisted power steering system for a motor vehicle includes a housing, a shaft slidably supported in the housing, a ball-and-nut mechanism operatively mounted on the shaft, and an electric motor mounted in the housing for transmitting rotary force from the electric motor through the ball-and-nut mechanism to the shaft. The ball-and-nut mechanism including a nut assembly disposed around the shaft and having one end rockably and rotatably supported in the housing by a four-point contact bearing or an automatic aligning bearing, and a plurality of balls movably held between an opposite end of the nut assembly and a screw groove defined in the shaft.

Abstract: In a control system for a front and rear wheel steering vehicle which steers the rear wheels so as to cancel a deviation of an actual yaw rate from a standard yaw rate which can be computed from the steering input, the vehicle speed and other parameters, there is provided a feature to automatically and manually cancel the yaw rate feedback control. If the actual yaw rate continues to exceed a threshold level for more than a certain time period, the yaw rate feedback is canceled gradually so as not to cause any abrupt change in the handling of the vehicle. Alternatively, if the vehicle operator wishes to operate the vehicle under extreme conditions, he may manually cancel the yaw rate feedback control so as to avoid undesirable interference or conflict between the manual steering effort and the yaw rate feedback control action. Thus, the maneuverability of the vehicle under extreme conditions can be improved without losing the benefits of the yaw rate feedback control.

Abstract: A diagnosing apparatus and method for determining an occurrence of failure in a rear road wheel steering angle sensor of a motor-driven four wheel steering system of an automotive vehicle which can achieve a highly accurate detection of the occurrence of failure in the single rear road wheel steering angle sensor at an appropriate timing irrespective of a sensor failure mode. The detection of failure in the rear road wheel steering angle sensor is carried out on the basis of whether a target deviation between a rear road wheel steering angle sensor value and a target rear road wheel steering angle exceeds a predetermined deviation value and whether a generation time duration during which the target deviation exceeds the predetermined deviation value has continued over a predetermined period of time. In addition, the detection of failure in the rear road wheel steering angle sensor is carried out on the basis of whether an accumulated value of a rear road wheel steering angle estimated deviation .intg..DELTA..

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.