Abstract: A steering control apparatus is provided which is capable of alleviating a decrease in the output torque of a motor during high-speed steering. The steering control apparatus includes a motor 5, a motor current instruction value generation section 100a, 100b for generating a current instruction value for the motor 5, a motor current detection section 102a, 102b for detecting a current flowing through the motor 5, wherein the motor 5 is driven to rotate based on at least the current, which flows through the motor 5, and the current instruction value. The motor current instruction value generation section includes a correction section 100b for correcting the current instruction value which controls the magnetic field of a field magnet of the motor 5, the correction section being operable to correct the current instruction value for controlling the magnetic field of the field magnet of the motor 5 when a steering speed is fast.

Abstract: An electric power steering equipment according to the present invention comprises a motor for providing a steering assisting force to a steering shaft, a torque detecting means for detecting a steering torque, an amplifying and phase-compensating means for amplifying and phase-compensating a detected value of the torque detecting means, and a controlling means for controlling a drive of the motor based on an output of the amplifying and phase-compensating means, wherein the controlling means restricts a control signal for driving the motor by an upper limit value and a lower limit value which are set in response to the detected value of the torque detecting means.

Abstract: A steering control apparatus includes a first power supply, a second power supply for outputting a voltage lower than the voltage of the first power supply, a motor for generating an auxiliary steering power, a controller for controlling the motor, and a driver for driving the motor in response to the output of the controller, wherein power is supplied from the first power supply to the driver and that power is supplied from the second power supply to the controller.

Abstract: An electrically powered steering system includes an electric motor for assisting a steering force based on a steering torque; and an electric motor driving circuit for driving the electric motor based on at least one of an inertia compensation current and a viscosity compensation current in case of failure. The inertia compensation current becomes greater as the electric motor has an angular acceleration increased and provides the electric motor with a torque in a direction identical to the electric motor angular acceleration. The viscosity compensation current becomes greater as the electric motor has an angular speed increased and provides the electric motor with a torque in a direction opposite to the electric motor angular speed.

Abstract: An electric power steering device constructed to detect a steering force by a driver and a vehicle speed respectively by a torque sensor and a vehicle speed sensor, set a steering force assisting current for a motor by a steering force assisting current setter using the detected steering force and the detected vehicle speed, set an upper limit value of a motor current by a motor current upper limit value setter based on a power function of a deviation between the set steering force assisting current and a predetermined motor current reference value, and perform overheat protection by setting an upper limit of a motor current applied by a motor driving circuit based on an integrated value of the motor current squared, whereby a problem of an insufficient steering assisting force when stationary steering is repeated many times while parking in a garage in a narrow parking area is solved.

Abstract: To improve a steering feeling, an estimated value of static friction of a steering system is obtained by static friction computing means and a static friction compensation current is computed based on this estimated value of static friction by static friction compensation current computing means to compensate for the static friction of the steering system.

Abstract: In the conventional electric power steering control system, a steering force applied by a driver to a steering wheel is detected and a torque of a motor is determined on the basis of the detected steering force. In such a prior system, at the time of going round a gentle curve, going round an intersection at an extremely low speed or the like, any steering wheel return torque is not generated unless the driver returns the steering wheel, and drive feeling is not improved. First, a road surface reaction torque estimator 15 estimates a road surface reaction torque on the basis of a steering wheel angle. A neutral point learning unit 24 and a neutral point compensator 25 learn a neutral point of the steering wheel on the basis of the road surface reaction torque with respect to the steering wheel angle. A return torque for returning the steering wheel to the neutral point is computed from a difference between a current angle of the motor and the learned neutral point.

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: In the conventional power steering control system, a road surface reaction torque is obtained by subtracting a motor inertia torque from a value obtained by adding a steering wheel steering torque and a motor torque and passing the value through a primary filter. In such computation, there is a disadvantage that high frequency components contained in steering wheel manipulation force brings about am unusually large steering wheel return force, and this gives a driver a feeling something like difficulty in adapting himself to the power steering. The system according to the invention is provided with a road surface reaction torque detector 115S in which a motor inertia torque is subtracted from a value obtained by adding a steering torque and a motor torque, and the value is passed through two stages of primary filters 100, 101 connected in two series thereby obtaining a road surface reaction torque.

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 motor-driven power steering apparatus comprises: a torque sensor for detecting a steering torque; an assist indicator for outputting an indication signal which indicates the direction and magnitude of an output torque of a motor power-assisting a steering mechanism; a dither signal generator for outputting a high-frequency dither signal; and a control circuit for controlling a current supplied to the motor according to the indication signal provided by the assist indicator and the dither signal provided by the dither signal generator.

Abstract: To estimate the rotation speed of the motor for assisting a steering torque regardless of the running state of a vehicle with accuracy, an application voltage estimation value obtained by subtracting a correction voltage obtained based on a detection current value detected by current detection means from the inter-terminal voltage measurement value of the motor is output and the rotation speed of the motor is estimated based on this application voltage estimation value and the detection current value.

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: 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: A load short-circuit failure detection apparatus comprises load current drive means 8, load current control means 7, load current detection means 6 and load short-circuit failure judging means 9 and judges that a short-circuit failure occurs in a load when a state in which a load current detection value exceeds a predetermined value within a first predetermined time continues for a second predetermined time so that the load drive means can be protected, a short-circuit failure of the load can be detected, and the erroneous detection of a short-circuit failure caused by a transient overcurrent can be prevented.

Abstract: A motor-driven power steering system for a motor vehicle implemented inexpensively in a simplified structure allows operation of a steering assist torque generating motor even in the vicinity of a neutral point while preventing rotation of the motor in a direction reverse to the steering direction as well as self-rotation of a steering wheel notwithstanding of occurrence of abnormality in a controller implemented by a CPU. The motor-driven power steering system includes a CPU (3) for controlling a motor (2) in dependence on output of a steering torque detecting unit (1), an interlock means (5) for limiting driving operation of the motor (2) upon occurrence of abnormality in the CPU (3), and a motor driving means (6) for driving the motor (2) in accordance with commands issued by the CPU (3).

Abstract: When a motor terminal voltage detector circuit fails, it is impossible to calculate a motor angular speed estimate, so a current is supplied to a steering-assist motor regardless of a driver's steering state, thus leading to abnormality in control of the steering force due to an electric power steering system. According to a first motor target current which is determined on the basis of a detected driver's steering force value and a second motor target current which is determined on the basis of a counter electromotive voltage across the motor, a third motor target current to be supplied to the motor is determined, and also an upper limit is set for the second or third target current. Also, failure of circuits necessary for calculating a counter electromotive voltage across the motor is detected.

Abstract: A method of detecting the angle of rotation of a DC motor includes the steps of: driving the DC motor with a predetermined torque for a predetermined period of time which is selected so that the angular acceleration of the DC motor is substantially constant during the above period of time; and calculating the angle of rotation of the DC motor from the driving time period and the voltage generated by the DC motor after the driving of the DC motor is stopped. This method makes it possible to accurately detect the angle of rotation and the load torque using an apparatus having a simple structure.

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: An electrically-operated steering apparatus in which in addition to avoiding an increase in cost caused by installing a new sensor or using a high process speed CPU, steering feels, such as steering wheel return, viscous feeling, inertial feeling and frictional feeling, are improved. In addition to assisting a static steering torque on the basis of a torque sensor, with a motor-applied voltage detection circuit capable of removing the square wave component attendant on the PWM drive of a motor, a motor angular velocity .omega. is estimated from the output data of the relevant circuit. A motor angular acceleration d.omega./dt is estimated from the motor angular velocity .omega. by using a differential calculator. The steering friction and the moment of inertia are compensated on the basis of the motor angular velocity .omega. and motor angular acceleration d.omega./dt, respectively.