Abstract: A rear wheel steering angle control apparatus is provided with a rear wheel steering angle determining unit and a rear wheel steering mechanism so as to determine a steering angle ratio based upon vehicle speed and perform a rear wheel steering angle control. An alerting unit alerts that the output of the rear wheel steering mechanism is beyond a predetermined allowable range when an observing unit detects a control condition being abnormal and releases the alert when the output of the rear wheel steering mechanism is within the predetermined allowable range.

Abstract: An electric power steering system includes a motor and a soft-disable controller in signal communication with the motor for reducing the abruptly increased reaction torque felt by a driver when an assist torque is abruptly disabled.

Abstract: A system for inducing inertia into a vehicles' steering gear. Following a high speed blowout the added inertia will hold the front wheels steady in their pre-blowout direction. The added inertia will prevent a reverse power flow from the front wheels to the steering wheel following a high speed blowout. The conventional power steering of the vehicle will be strengthened so that the operation of the steering wheel by the driver will easily overcome the increased inertia of the vehicles' steering gear.

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

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: An abnormality detection circuit for detecting abnormality of a CPU includes a command value check circuit for checking whether a current command value calculated by the CPU is normal or abnormal with respect to a torque signal, and a drive signal check circuit for checking whether a motor drive signal outputted based on the current command value is normal or abnormal. When the command value abnormality of the CPU is detected by the abnormality detection circuit, a counter circuit is started to count a time of an abnormality state of the CPU. If the counted time reaches a predetermined time, a control stop command is outputted from a system stop circuit to the CPU, thereby stopping the system control of the CPU.

Abstract: A steering gearbox mechanism for automotive vehicles which allows the connection and disconnection of the steering gearbox assistance mechanism (hydraulic, electric or the like), depending on the vehicle working conditions. Thus, when the vehicle is stopped or circulating at a very low speed, the assistance mechanism assists the steering mechanism allowing the user to carry out the maneuver effortlessly, and when the vehicle circulates at a higher speed, the assistance is disconnected, and the vehicle's engine does not impel the pump since the user can carry out any maneuver without any effort. Summing up, the present invention is referred to a power steering gearbox mechanism for vehicles, comprising an assisted rack bar-and-pinion steering mechanism characterized by comprising a control means that detects the vehicle's working condition, and at a certain speed is capable of sending a signal for disconnecting the steering assistance.

Abstract: A steering device for steering the wheels of a steering axle of a motor vehicle having at least three axles. The steering axle is designed as a trailing or leading axle, with a hydraulic arrangement which has an actuating assembly for the steering actuation of the wheels, and a regulating/control valve for pressure to act upon hydraulic connections of the actuating assembly and a clearing valve, by means of which the steering device can be changed over between normal operation and emergency operation. In the emergency operation, the hydraulic connections of the actuating assembly are connected to one another. Four throttle elements are provided. The first is arranged upstream and the second downstream of a connection point of the clearing valve to a first hydraulic line connecting the regulating/ control valve and actuating assembly.

Abstract: A controller for controlling the assist steering torque of an electric motor in an electric power steering apparatus has a relay failure detection unit for detecting ON failure which arises in a relay circuit provided between an electric motor driving circuit and a power supply; and a relay failure correction unit for decreasing the assist steering torque, at least the maximum value of the assist steering torque, of the electric motor based on a failure detection signal from the relay failure detection unit. Thereby, manual steering by a steering wheel with a heavier steering torque than the torque at the time of a normal mode becomes possible as deal at the time that ON failure arises in a relay circuit.

Abstract: An electric power steering device controls an electric motor through a program processing based on a steering torque detected by a torque sensor and a vehicle speed detected by a vehicle speed sensor, and applies a suitable assisting force to rotational motion of a steering handle. Occurrence of an abnormality in the torque sensor and a power circuit is detected through the program processing. The torque sensor is activated upon receipt of a power-supply voltage from the power circuit and detects a steering torque. If a power-supply voltage outputted from the power circuit has dropped, detection of an abnormality in the torque sensor is forbidden. If a power-supply voltage supplied from a battery to the power circuit has dropped, detection of an abnormality in the power circuit is forbidden.

Abstract: An apparatus (10) for turning the steerable wheels (17) of a vehicle in response to the turning of the steering wheel (12). The apparatus (10) includes a drive mechanism (16), a first motor (24), a second motor (74), a sensor (78) for sensing that the first motor (24) is inoperative, and a torque sensor (80). In response to the turning of the steering wheel (12), the drive mechanism (16), is actuated, resulting in a turning the steerable wheels (17). The first motor (24), for inputting motion to the drive mechanism (16), is hydraulically powered. The second motor (74), for inputting motion to the drive mechanism (16), is electrically powered. The sensor (78) for sensing that the first motor (24) is inoperative produces an enabling signal and communicates the enabling signal to the second motor (74) to enable the operation of the second motor (74). The torque sensor (80) responds to the turning of the steering wheel (12) and controls the second motor (74) when the second motor (74) is enabled.

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 electric power steering apparatus includes a motor 1 which produces an auxiliary steering force in accordance with, for example, a steering torque detected by a torque sensor 7; a motor drive circuit 2 which controllably drives the motor 1; a power supply voltage detecting circuit 17 which detects the power supply voltage VB of the motor drive circuit 2; and a microcomputer 9. The microcomputer 9 detects terminal voltages VM+ and VM− of the motor 1 when the power supply voltage detecting circuit 17 determines that the power supply voltage AB is higher than a predetermined value. Then, the microcomputer 9 makes a decision to determine whether the detected terminal voltages VM+ and VM− are not predetermined values VTHH and VTHL, respectively. If it is determined that the terminal voltages VM+ and VM− are not the predetermined values VTHH and VTHL, respectively, then the microcomputer 9 determines that a fault has occurred on the lines connected to the motor 1.

Abstract: A device for controlling the steering angle of a vehicle over a wide range maintaining improved control precision. The device controls the steering angle &thgr;d through a steering drive device 10 so as to come in agreement with a target angle &thgr;0. A steering angle detection device includes a first potentiometer 11 that produces a first angle detection value &thgr;1 and a second potentiometer 12 that produces a second angle detection value &thgr;2. A target torque operation means 20 includes an angle operation unit 22 for operating the steering angle based on the first and second angle detection values, and the angle operation unit 22 produces the first angle detection value as the steering angle outside the second angular range, and produces the second angle detection value as the steering angle inside the second angular range.

Abstract: To keep low the cross frequency of current feedback control and provide a good steering feeling, a first operation expression is selected when a difference &xgr; between a current instruction value computed based on a steering state of a steering wheel and a traveling state of a vehicle and a motor drive current value supplied from a battery to a motor for providing assist force to a system for transmitting power from the steering wheel to the wheels is larger than a predetermined value Th1, a second operation expression is selected when the difference &xgr; is smaller than the predetermined value Th1, and the difference &xgr; is corrected using the selected operation expression.

Abstract: A closed-center hydraulic power steering system includes a rechargeable hydraulic pressure accumulator being capable of being connected to a servomotor via controllable pressure-reducing valves which control the motor pressure according to a desired value predetermined by a control device, a connection also being made, if required, between the motor and a relatively pressureless reservoir.

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: A steering system for a motor vehicle is not trackbound and has steered vehicle wheels which are connected only operationally in normal operation to a steering handwheel via an electronic control arrangement which actuates a steering actuator in accordance with a desired-value stipulation by way of the steering handwheel. In emergencies, a mechanical positive coupling becomes effective between the steering handwheel and the steered vehicle wheels. The operational state of the clutch is monitored by a sensor system in the case of normal operation, with the result that the normal operation can remain switched on only if the clutch is unambiguously open.

Abstract: An automatic steering device for a vehicle is provided to prevent an automatically steered vehicle from going out of its predetermined locus of movement as a result of an abnormal output of a movement distance detecting device. An actuator control device controls a steering actuator based upon the distance of movement detected by the movement distance detecting device and upon a locus of movement of the vehicle stored in a storage device. A judging device compares a vehicle speed estimated by a vehicle speed estimating device with an actual vehicle speed calculated by an actual vehicle speed detecting device from the distance of movement based upon the operating condition (shift range, accelerator opening degree and brake operating amount) of the vehicle detected by an operating condition detecting device.

Abstract: A vehicle steering apparatus having a variable gear ratio unit arranged midway along a steering transmission system for connecting a steering wheel and a tire to change a transmission ratio upon driving a motor includes a connecting unit for stopping actuation of the variable gear ratio unit in accordance with an external signal to connect the input side of the variable gear ratio unit which is connected to the steering wheel to the output side of the variable gear ratio unit which is connected to the tire. Even if a reverse input acts from a tire side during traveling, the relationship between the steering amount of the steering wheel and the turning amount of the tire can be kept unchanged.

Abstract: Electric power steering apparatus includes a control unit for setting a motor control signal to control operation of an electric power assisting motor on the basis of at least steering torque detected by a steering torque sensor and a vehicle velocity detected by a vehicle velocity sensor. The control unit includes a steering torque estimating section for estimating the steering torque on the basis of the vehicle velocity detected by the vehicle velocity sensor and a steering angle detected by a steering angle sensor. When the steering torque sensor is out of order or malfunctioned, the control unit controls the operation of the electric motor on the basis of the steering torque estimated by the steering torque estimating section.

Abstract: The present invention provides a steering angle middle point detecting device which does not need a torque sensor, can detect a steering angle middle point with high precision without being affected by driving habits of drivers and road conditions, and can reduce memory size, and a power steering apparatus having the device. A continuous time period during which the vehicle speed is higher than a predetermined value and the steering angular velocity is lower than a predetermined value is counted, and each time the counted time has reached a predetermined time period, a detected steering angle and current are stored in a first memory.

Abstract: According to the invention, there is provided is a vehicle steering system which can improve the resistance of a vehicle against external disturbances such as crosswind, and can prevent the operability of the steering system from being seriously affected by a failure in a part of the system related to the generation of steering reaction such as a lateral acceleration sensor, a yaw rate sensor or a reaction control unit. Because the assisting steering torque continues to be produced even when a failure has occurred in a part related to the generation of steering reaction. Therefore, a fail-safe feature can be obtained, and unnecessary loss of the operability of the steering system can be avoided. By reducing the assisting steering torque from the normal level, which is effective when the sensors are operating normally, at such a time, the driveability of the steering system similar to that under the normal condition can be ensured.

Abstract: A failure detection system for detecting an operational failure of a rack and pinion type of hydraulically controlled power steering system which employs a power cylinder to assist the driver in manipulating front wheels of the vehicle by utilizing hydraulic pressure applied to a steering gear connected to the front wheels utilizes a pressure switch for detecting a specified level of oil pressure provided by the power cylinder to be at operational failure when the vehicle speed remains higher than a specified speed for a specified time period, the pressure switch detects the specified level of hydraulic pressure.

Abstract: A power steering device includes a hydraulic pump for discharging working fluid, an actuator for producing a steering assisting force by means of working fluid, a hydraulic passage for connecting the hydraulic pump and the actuator, a check valve arranged to the hydraulic passage to allow flow of working fluid from the hydraulic pump to the actuator and preventing flow thereof in the opposite direction, an accumulator connected to the hydraulic passage downstream of the check valve, a pressure switch for detecting a pressure within the hydraulic passage downstream of the check valve, a control unit for controlling the hydraulic pump in response to the pressure switch, and a display for showing an anomaly of the power steering device. When determining the anomaly of the power steering device, the control unit stops the hydraulic pump and/or makes the display show the anomaly.

Abstract: A control apparatus for a motor-driven power steering system of a motor vehicle controls the steering system such that a steering torque required to be applied by a driver is prevented from increasing abruptly or steeply even when generation of an assist torque applied to the steering system for assisting the driver in steering operation is to be stopped.

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 an electromotive power steering device, when input is received in a reverse direction, i.e., from the road, no assist torque connection is made in the reverse direction. The upper inertial moment is appropriately compensated for. Detection signals from each sensor are received and converted to an input torque, vehicle speed and phase angle. An assist torque command value is calculated from the input torque and the vehicle speed, and an angular velocity and angular acceleration are calculated from the phase angle. Subsequently, the inertial moment of the steering wheel is read and multiplied by the angular acceleration, thereby computing the inertial torque of the steering wheel. It is then determined whether the multiplication of the input torque and the angular velocity results in a positive value or a negative value. Only when the value is positive, correction is made of the assist torque command value.

Abstract: In an electric power steering apparatus, a motor current target value of a steering force assisting motor is determined on the basis of a torque detected by a torque sensor. The drive of the motor is controlled using the motor current target value as a target value of an automatic control, and using the driving current of the motor as a feedback value of the automatic control. When the detected torque is within a predetermined range, the motor is inhibited from being driven in the direction opposite to the detected torque. The electric power steering apparatus has a motor non-drive detecting circuit for detecting that the motor current target value is zero, and a drive inhibition holding circuit for holding the motor drive inhibition state, wherein the motor is inhibited from being driven in the direction opposite to the detected torque, until the motor non-drive detecting circuit detects that the motor current target value is zero.

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: 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 motor-driven power steering control system of a motor vehicle for assisting a driver in manipulating a steering wheel by making use of an assist torque generated by a reversible motor which is operatively coupled to a steering mechanism of the motor vehicle includes an electric reversible motor mechanically coupled to a steering system of the motor vehicle through an electromagnetic clutch, a motor drive circuit, an H-bridge switching driver circuit for driving the electric reversible motor in forward or reverse direction under the control of the motor drive circuit, and a clutch control circuit for controlling the electromagnetic clutch.