Jtekt Corporation

Shigeto Matsuo

Terutaka Tamaizumi

Akihiko Nishimura

Tetsuya Nozawa

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.

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.

Steering control unit

The microcomputer calculates a first assist component based on a vehicle speed value and a steering torque, calculates a rotation angle command value based on at least the vehicle speed value and a first assist component, and calculates a second assist component by adjusting a rotation angle to the rotation angle command value through feedback control. The microcomputer sets a limited statewhere the second assist component is disabled when a vehicle is stationary. During an abnormality determination period during which the vehicle speed value is determined to be abnormal, the microcomputer sets the vehicle speed value to a provisional vehicle speed value. Further, in a limited statethat is set when the vehicle is stationary during the abnormality determination period, the microcomputer calculates the first assist component based on a provisional vehicle speed value, and disables the second assist component.

Steering control system

A steered-angle command value calculation circuit calculates a steered-angle command value by adding a steering torque to a first assist component that is a sum of a basic assist control amount, a hysteresis control amount and a damping control amount. A steered-angle feedback control circuit calculates a second assist component by angle feedback control based on the steered-angle command value. A compensation control circuit generates the hysteresis control amount and the damping control amount based on a determination flag generated by a hand release determination circuit and indicating whether or not the steering state corresponds to a hand release state. The hand release determination circuit determines whether or not the steering state corresponds to the hand release state based on signs of a steering angle calculated by a steering-angle calculation circuit, a steering angular velocity that is a differential value of the steering angle, and a steering angle acceleration.

Steering control apparatus

In a drive assist control apparatus, based on a pinion angle command value and an LKA angle command value, a distribution ratio calculation unit calculates a distribution ratio that is a proportion of the LKA angle command value in a sum of the LKA angle command value and the pinion angle command value. An LA determination unit compares an LA threshold with a lateral acceleration that is related to the LKA angle command value and that is a product of a lateral acceleration and the distribution ratio, and determines whether or not to attenuate the lateral acceleration. When the lateral acceleration is determined to be attenuated, an LKA angle command value correction unit uses a low pass filter to progressively reduce the LKA angle command value to generate a filtered LKA angle command value.

Growing community of inventors

Kako-gun, Japan

Shigeto Matsuo