Patent application number | Description | Published |
20080243341 | VEHICLE STEERING APPARATUS - A steered shaft of a steered mechanism is rigidly fixed to a vehicle body. Steering-stiffness is reduced by a lowpass filter for filtering a steered angle detected by a steered angle sensor. A deviation between a target steered angle and the filtered steered angle detected by the steered angle sensor is input to a PID control unit. A gain setting unit sets each of gains for PID control at a low value to thereby reduce steering-stiffness. The PID control unit outputs a target current. A drive circuit performs, e.g., PID control of the steering actuator. | 10-02-2008 |
20090064815 | VEHICLE STEERING APPARATUS - A vehicle steering apparatus includes a steering member for rotational operation, and a support mechanism that supports the steering member so as to be movable between a housing position where the steering member is housed in a fixed frame of an instrument panel and a projection position where the steering member projects to an outside of the fixed frame. The steering member includes a main body supported by the support mechanism, a pair of grip sections which are movable between the housing position and the projection position together with the main body, and which are supported so as to be movable between a nonoperating position and an operating position by the main body, and a grip section drive actuator which is supported by the main body, and drives the pair of grip sections to the nonoperating position and the operating position. | 03-12-2009 |
20090065285 | VEHICLE STEERING APPARATUS - A vehicle steering apparatus, includes a steering member for rotational operation, a support mechanism that supports the steering member so as to be movable between a housing position where the steering member is housed in a fixed frame of an instrument panel and a projection position where the steering member projects to an outside of the fixed frame, and that regulates an attitude of the steering member located between the housing position and the projection position, and a movable frame that moves together with the steering member, and that constitutes a part of the instrument panel by covering an opening formed in the fixed frame of the instrument panel when the steering member is housed at the housing position. | 03-12-2009 |
20100235049 | Motor control unit and motor control unit for vehicle steering apparatus - A motor control unit controls a motor including a rotor and a stator facing the rotor. A current drive unit drives the motor at an axis current value of a rotating coordinate system that rotates in accordance with a control angle that is a rotational angle used in a control. A control angle calculation unit obtains, at every predetermined calculation cycle, a present value of the control angle by adding an addition angle to an immediately preceding value of the control angle. A torque detection unit detects a torque other than a motor torque and applied to a drive target driven by the motor. A command torque setting unit sets a command torque to be applied to the drive target. An addition angle calculation unit calculates the addition angle to be added to the control angle through a proportional-integral control based on a torque deviation of the torque detected by the torque detection unit from the command torque set by the command torque setting unit. | 09-16-2010 |
20120080259 | MOTOR CONTROL DEVICE AND ELECTRIC POWER STEERING APPARATUS - An angular velocity estimate (ωe) used in motor control of an electric power steering is obtained as follows. In a first state period during which the motor substantially stops its rotation, a resistance calculation unit calculates a motor resistance value (Rc) on the basis of a detected value (Vm) of motor voltage and a detected value (Im) of motor current. An average calculation unit obtains an average value (Rav) of the calculated resistance values (Rc) in a retained period. A current-resistance characteristic that associates motor current with motor resistance is held in a characteristic holding unit, and a characteristic updating unit updates the current-resistance characteristic on the basis of the average value (Rav). An estimate calculation unit calculates the angular velocity estimate (ωe) on the basis of the detected value (Vm) of motor voltage, the detected value (Im) of motor current and a motor resistance value (Rm) obtained from the current-resistance characteristic. | 04-05-2012 |
20120253603 | VEHICLE STEERING APPARATUS - A vehicle steering apparatus in which a mechanical coupling between a steering member and steered wheels is uncoupled, includes a steering actuator for driving a steered mechanism and a control unit for drive-controlling the steering actuator. The control unit reduces steering-stiffness using a PID control portion for drive-controlling the steering actuator according to a deviation between a target steered angle and a steered-angle detected by the steered angle sensor. A gain setting portion sets gains of the PID control portion to be relatively low when a predetermined condition is satisfied. | 10-04-2012 |
Patent application number | Description | Published |
20120055732 | ELECTRIC POWER STEERING SYSTEM - An electric power steering system includes a motor that applies assist force to a steering system, and updates a motor resistance (Rm) that is a value indicating a resistance of the motor. Specifically, the motor resistance (Rm) is updated on the basis of the fact that an induced voltage (EX) of the motor is smaller than a first determination value (GA). In addition, when the induced voltage (EX) is smaller than or equal to a second determination value (GB), a divided value that is obtained by dividing a motor voltage (Vm) by a motor current (Im) is set as a new motor resistance (Rm). | 03-08-2012 |
20120059550 | ELECTRIC POWER STEERING SYSTEM - An electric power steering system determines a steering state of a steering wheel on the basis of a current (Im) of a motor applying assist force to a steering system and a steering speed (ωs) of the steering wheel. A state where the steering wheel is retained at a position other than a neutral position is a retained state, and a state where the steering wheel is placed at the neutral position is a neutral state. When the steering speed (ωs) is lower than a determination value (ωa) and the motor current (Im) is larger than a reference value (Ix), it is determined whether the steering state is the neutral state. When the steering speed (ωs) is lower than the determination value (ωa), the motor current (Im) is larger than the reference value (Ix), and the steering state is determined to be the neutral state at immediately preceding determination, the steering state is determined to be the neutral state. | 03-08-2012 |
20120229126 | ROTATION ANGLE DETECTION DEVICE - When the zero-crossing of one of the output signals of magnetic sensors has been detected, a rotation angle computing device identifies a magnetic pole sensed by the first magnetic sensor based on the other two output signals. Subsequently, the rotation angle computing device identifies the magnetic pole sensed by the second magnetic sensor and the magnetic pole sensed by the third magnetic sensor based on the magnetic pole sensed by the first magnetic sensor. After that, the rotation angle computing device corrects the amplitude of the output signal of each magnetic sensor based on the identified magnetic poles respectively sensed by the magnetic sensors. Then, the rotation angle computing device computes the electric angle θe of the rotor based on the corrected output signals. | 09-13-2012 |
20140343789 | ELECTRIC POWER STEERING SYSTEM - There is provided an electric power steering system that is able to generate a more appropriate current command value. Limits of an assist controlled variable, formed of multiple upper limits and multiple lower limits are individually set for multiple signals used to compute the assist controlled variable. The values obtained by adding the limits together are set as final limits of the assist controlled variable, that is, an upper limit and a lower limit. Thus, even if the assist controlled variable exhibiting an abnormal value is computed for some reason, the abnormal value of the assist controlled variable is limited to an appropriate value corresponding to each signal value by the final limits. By supplying the appropriate assist controlled variable to a motor control signal generating unit as a final current command value, an appropriate assist force is applied to a steering system. | 11-20-2014 |