Jtekt Corporation

Akihiko Nishimura

Terutaka Tamaizumi

Jun Hasegawa

Masayuki Kita

Shigeto Matsuo

Hirozumi Eki

Isao Namikawa

Shinya Aono

Akira Nambu

Yoshihiko Sugimoto

This steering control device is provided with a microcomputer. The microcomputer includes: a basic assist component calculation unit for calculating a basic assist component; an angle command value calculation unit for calculating an angle command value; an angle feedback control unit that calculates an assist command value via angle feedback control in which a pinion angle is made to follow the angle command value; and a control signal generation unit that generates a motor control signal on the basis of the assist command value. The basic assist component calculation unit includes: a torque command value calculation unit for calculating a torque command value that is a target value for steering torque to be input by a driver; and a torque feedback control unit that calculates the basic assist component via torque feedback control in which the steering torque is made to follow the torque command value.

Steering control device

A driving assistance control device outputs a driving assistance command value to a steering control device as information indicating a target course that is generated on the basis of the detection result of a vehicle-mounted sensor. The driving assistance command value is output as a torque component or an angle component depending on the design of the driving assistance control device. In response, processing in which a driving assistance command value input from the exterior of the steering control device is used as input for angle control processing or input for torque control processing within an assist command value calculation unit is performed by a microcomputer as assistance command value input processing by an assistance command value input processing unit.

A steering control unit includes a microcomputer that controls the driving of a motor on the basis of a steering torque to cause the motor to produce an assist force that is supplied to a steering mechanism as power to steer front wheels. The microcomputer calculates, on the basis of the steering torque, an assist component indicative of the assist force that the motor needs to produce. The microcomputer obtains vertical forces related to the front wheels that are calculated by hub units that rotatably support the front wheels and have front wheel sensors for detecting forces applied to the front wheels. The microcomputer compensates the assist component by using the obtained vertical forces, to reduce a change in load on a driver that is caused when vertical loads on the front wheels change.

Steering control unit

A steering control apparatus includes a microcomputer configured to control driving of a motor based on a steering torque so as to generate, for a steering mechanism, an assist force as power for turning front wheels. The microcomputer calculates an assist component indicating the assist force to be generated in the motor based on the steering torque, acquires steered moments about axes extending in a vertical direction of the front wheels from hub units that rotatably support the front wheels and include front wheel sensors configured to detect forces applied to the front wheels, respectively, and compensates for the assist component by using the acquired steered moments so as to generate, in the motor, a vibration suppressing force for suppressing a reverse input vibration.

Steering control apparatus

The microcomputer included in the steering control unit calculates a basic assist component that is a component of the assist force, on the basis of the steering torque. The microcomputer calculates a damping compensation component that suppresses a sudden change in a rotation angle, on the basis of a rotational angular velocity that is a time rate of change of the rotation angle. The microcomputer calculates, independently of the damping compensation component, a return compensation component that suppresses influence of the damping compensation component, on the basis of the rotational angular velocity. The microcomputer compensates the basic assist component by using both the damping compensation component and the return compensation component, in a situation where the steering wheel comes back to the neutral position without a steering operation that a driver performs to return the steering wheel.

A steering control system with which a steering angle accurately follows a steering angle command value is provided. An assist command value calculation circuit calculates a first assist component based on a value obtained by adding a basic assist controlled variable with a system stabilization controlled variable. The assist command value calculation circuit includes a pinion angle feedback control circuit that calculates a second assist component by executing angle feedback control based on a deviation between a pinion angle and a final pinion angle command value that is the sum of a pinion angle command value and an ADAS command angle. The assist command value calculation circuit outputs an assist command value based on the first assist component and the second assist component. The assist command value calculation circuit receives a steering torque obtained after the influence of viscosity and inertia is reduced by a steering torque compensation circuit.

Steering control system

A control device in an electric power steering device calculates a first assist component based on steering torque and a vehicle speed. The control device also calculates a compensation component associated with an reverse input and calculates a steered angle command value based on an addition value of the compensation component and basic drive torque that is an addition value of the steering torque and the first assist component, produces a second assist component by performing steered angle feedback control that causes the steered angle of a vehicle to follow the steered angle command value. The control device controls drive of a motor based on an assist command value that is an addition value of the first assist component and the second assist component.

Electric power steering device

There is provided an electric power steering system that makes it possible to improve the driver's steering feel, and that includes a controller that controls driving of a motor. The controller computes a first assist component based on a steering torque. The controller computes a torque command value based on a basic drive torque that is the sum of the steering torque and the first assist component, and computes an assist compensation component through feedback control based on the torque command value. The controller computes a steered angle command value based on a value obtained by adding the assist compensation component to the basic drive torque, and computes a second assist component through feedback control based on the steered angle command value. The controller controls driving of the motor based on an assist command value that is the sum of the first assist component and the second assist component.

Electric power steering system

A steering torque shift control amount calculation unit () calculates the steering torque shift control amount (&#x3b5;ts) by multiplying the basic shift amount (&#x3b5;ts_b) used as the basic compensation component by the transition coefficient (Kss). Then, the steering torque shift control amount (&#x3b5;ts) is subjected to the low-pass filter process in an abrupt change prevention processing unit (). An abrupt change prevention processing unit () is provided in the steering torque shift control amount calculation unit (). The transition coefficient (Kss) is subjected to the low-pass filter process in the abrupt change prevention processing unit (). The cutoff frequency of the low-pass filter that forms the abrupt change prevention processing unit () is set to a value lower than the cutoff frequency of the low-pass filter that forms the abrupt change prevention processing unit () that executes the low-pass filter process on the torque shift control amount (&#x3b5;ts).

A microcomputer is provided with an extracting section capable of extracting a specific frequency component from an input signal. The extracting section extracts, from a pinion angle corresponding to a signal indicating a state of the steering system, a frequency component corresponding to a vibration of a steering system caused by stress applied to steerable wheels. The extracting section outputs an effective value of the extracted frequency component as a power spectrum to a second computing section. In the case that the power spectrum output from the extracting section is equal to or more than a predetermined threshold value, the microcomputer enhances a torque inertia compensation control so as to suppress vibration of the steering system caused by the stress. In other words, the microcomputer increases a torque inertia compensation amount corresponding to a compensation component based on a steering torque differential value.

Electric power steering apparatus

An electric power steering (EPS) apparatusincludes a motor, an EPS actuator, a torque sensor, and an ECU. The EPS actuatoruses the motoras a drive source to apply assist force to a steering system, thereby assisting a steering operation. The torque sensordetects a steering torque &#x3c4; of the steering system. The ECUcontrols the operation of the EPS actuator. Based on the steering torque &#x3c4; detected by the torque sensor, the ECUcomputes a basic shift amount &#x3b5;ts_b of the assist force applied to the steering system. The ECUdetermines which one of returning, holding, and turning is the state of the steering operation. When the state of the steering operation is returning or holding, the ECUexecutes compensation control for correcting the steering torque &#x3c4;, which is used in the computation of the basic shift amount &#x3b5;ts_b of the assist force, thereby increasing the assist force applied to the steering system. The ECUsubjects the steering torque shift control amount &#x3b5;ts to a filtering process using a low pass filter, thereby inhibiting the steering torque shift control amount &#x3b5;ts from sharply changing. When the state of the steering operation is turning, the ECUchanges a filter constant of the low pass filter so as to reduce the filtering effect.

A microcomputer is provided with an extracting section capable of extracting a specific frequency component from an input signal. The extracting section extracts, from a pinion angle corresponding to a signal indicating the state of a steering system, a frequency component corresponding to a vibration that increases generation of a rattling noise in a speed reducing mechanism. The extracting section outputs an effective value of the extracted frequency component as a power spectrum. If the power spectrum output from the extracting section is equal to or more than a predetermined threshold value, the microcomputer outputs a motor control signal to reduce the assist force generated by the EPS actuator.

An electric power steering apparatus is provided for suppressing the effect on the steering wheel of external interference inputted from the tie rod. The apparatus includes first and second output units for outputting first and second control amounts in accordance with the outputted torque signal, except in a dead zone thereof, respectively. The apparatus also includes gain data output units for, when the torque signal, a steering angular velocity, and a vehicle speed are within predetermined ranges, outputting gain data respectively. Steering operation is assisted by an electric motor driven on the basis of the first and second control amounts and the gain data, which afford a control signal to the motor.

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Okazaki, Japan

Akihiko Nishimura