US-12623505-B2 - Suspension control device and suspension control method

US12623505B2US 12623505 B2US12623505 B2US 12623505B2US-12623505-B2

Abstract

A suspension control device that is connected to a sensor that acquires information regarding a vehicle or surrounding information of the vehicle, and calculates a suspension control value for controlling a suspension of the vehicle based on the information acquired by the sensor includes: a reached vibration generation unit that generates a reached vibration reaching the vehicle based on the information acquired by the sensor; a sampling processing unit that samples a vibration waveform of the reached vibration by changing a time width for sampling the vibration waveform of the reached vibration according to a frequency of the reached vibration generated by the reached vibration generation unit; and a control value calculation unit that calculates the suspension control value based on a sampling value of the vibration waveform sampled by the sampling processing unit.

Inventors

Akihito Akai
Ryusuke Hirao

Assignees

HITACHI ASTEMO, LTD.

Dates

Publication Date: 20260512
Application Date: 20220421
Priority Date: 20210511

Claims (11)

1 . A suspension control device that is connected to a sensor that acquires information regarding a vehicle or surrounding information of the vehicle, and calculates a suspension control value for controlling a variable damping force of a suspension of the vehicle based on the information acquired by the sensor, the suspension control device comprising: a processor, a memory, and a storage, the processor configured to perform: a vibration generation function that generates a vibration expected to reach the vehicle based on the information acquired by the sensor, the information including a road surface of the vehicle; a frequency determination function that determines a frequency of the vibration expected to reach the vehicle generated by the vibration generation function; a sampling processing function that samples a vibration waveform representing a topography of the road surface of the vehicle of the vibration expected to reach the vehicle by changing a time width for sampling the vibration waveform of the vibration expected to reach the vehicle according to the determined frequency of the vibration expected to reach the vehicle generated by the vibration generation function; and a control value calculation function that calculates the suspension control value based on a sampling value of the vibration waveform sampled by the sampling processing function, wherein the sampling processing function samples the vibration waveform representing a topography of the road surface of the vehicle according to a predetermined number of sampling values regardless of the time width, and wherein the suspension control device controls the variable damping force of the suspension based on the calculated suspension control value.
2 . The suspension control device according to claim 1 , wherein the sampling processing function sets a number of sampling values when sampling the vibration waveform of the vibration expected to reach the vehicle to a constant number regardless of the frequency of the vibration expected to reach the vehicle.
3 . The suspension control device according to claim 2 , wherein the sampling processing function samples the vibration waveform of the vibration expected to reach the vehicle in a state in which the time width is set to be large and the sampling interval is set to be wide in a case where the frequency of the vibration expected to reach the vehicle is low, and in a state in which the time width is set to be small and the sampling interval is set to be narrow in a case where the frequency of the vibration expected to reach the vehicle is high.
4 . The suspension control device according to claim 1 , wherein the vibration expected to reach the vehicle generation function predicts the vibration expected to reach the vehicle reaching the vehicle based on a road surface displacement acquired by the sensor and a vehicle speed of the vehicle.
5 . The suspension control device according to claim 4 , wherein the information acquired by the sensor includes at least one of a camera image, a piston speed of the suspension, or a spring vertical acceleration of the vehicle.
6 . The suspension control device according to claim 1 , further comprising a road surface profile acquisition function that acquires road shape information at a current position of the vehicle, wherein the vibration expected to reach the vehicle generation function predicts the vibration expected to reach the vehicle reaching the vehicle based on the road surface displacement created from the road shape information and a vehicle speed of the vehicle.
7 . The suspension control device according to claim 6 , wherein the road surface profile acquisition function downloads the road shape information from a server device.
8 . The suspension control device according to claim 1 , wherein the control value calculation function includes a neural network, and the neural network calculates the suspension control value by using a weight parameter corresponding to the frequency of the vibration expected to reach the vehicle.
9 . The suspension control device according to claim 8 , wherein a number of sampling values of the vibration waveform sampled by the sampling processing function is a constant number regardless of the frequency of the vibration expected to reach the vehicle, and an input layer of the neural network includes a same number of elements as the number of sampling values of the vibration waveform.
10 . A suspension control method in a suspension control device that controls a variable damping force of a suspension of a vehicle by using a sensor that acquires information regarding the vehicle or surrounding information of the vehicle, the suspension control method comprising: generating a vibration expected to reach the vehicle based on the information acquired by the sensor, the information including a road surface of the vehicle; determining a frequency of the generated vibration expected to reach the vehicle; sampling a vibration waveform of the vibration expected to reach the vehicle by changing a time width for sampling the vibration waveform of the vibration expected to reach the vehicle according to the frequency of the generated vibration expected to reach the vehicle; calculating a suspension control value based on a sampling value of the sampled vibration waveform; and controlling the suspension based on the calculated suspension control value, wherein the sampling samples the vibration waveform representing a topography of the road surface of the vehicle according to a predetermined number of sampling values regardless of the time width.
11 . The suspension control method according to claim 10 , wherein a number of sampling values of the sampled vibration waveform is a constant number regardless of the frequency of the vibration expected to reach the vehicle, and the suspension control value is calculated by applying a weight parameter corresponding to the frequency of the vibration expected to reach the vehicle to a neural network in which an input layer includes a same number of elements as the number of sampling values of the vibration waveform.

Description

TECHNICAL FIELD The present invention relates to a suspension control device and a suspension control method. BACKGROUND ART There is known a suspension control device that controls a posture of a vehicle by changing rigidity, characteristics, and the like of a suspension according to a road surface condition and a driving condition. PTL 1 discloses a device that continuously acquires high density road surface displacement information of a road surface in front of a vehicle and reduces a probability of occurrence of detection omission of a height of the road surface to obtain highly accurate road surface displacement information, and supplies the obtained road surface displacement information to a suspension system of the vehicle for preview control of an active suspension. CITATION LIST Patent Literature PTL 1: WO 2017/169365 A SUMMARY OF INVENTION Technical Problem The device disclosed in PTL 1 cannot accurately grasp a vibration waveform based on a frequency of a reached vibration reaching the vehicle, and thus, there is a possibility that the suspension cannot be optimally controlled. Solution to Problem A suspension control device according to the present invention is a suspension control device that is connected to a sensor that acquires information regarding a vehicle or surrounding information of the vehicle, and calculates a suspension control value for controlling a suspension of the vehicle based on the information acquired by the sensor, the suspension control device including: a reached vibration generation unit that generates a reached vibration reaching the vehicle based on the information acquired by the sensor; a sampling processing unit that samples a vibration waveform of the reached vibration by changing a time width for sampling the vibration waveform of the reached vibration according to a frequency of the reached vibration generated by the reached vibration generation unit; and a control value calculation unit that calculates the suspension control value based on a sampling value of the vibration waveform sampled by the sampling processing unit. A suspension control method according to the present invention is a suspension control method in a suspension control device that controls a suspension of a vehicle by using a sensor that acquires information regarding the vehicle or surrounding information of the vehicle, the suspension control method including: generating a reached vibration reaching the vehicle based on the information acquired by the sensor; sampling a vibration waveform of the reached vibration by changing a time width for sampling the vibration waveform of the reached vibration according to a frequency of the generated reached vibration; calculating a suspension control value based on a sampling value of the sampled vibration waveform; and controlling the suspension based on the calculated suspension control value. Advantageous Effects of Invention According to the present invention, a vibration waveform can be grasped regardless of a frequency of a reached vibration reaching the vehicle, so that the controllability of the suspension can be improved. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating a suspension control model. FIG. 2 is a block configuration diagram of an electronic control device. FIGS. 3(A), 3(B), and 3(C) are diagrams illustrating information acquired from a vehicle sensor or the like and reached vibration frequency analysis. FIGS. 4(A), 4(B), and 4(C) are diagrams illustrating a road surface and a vibration amplitude. FIGS. 5(A), 5(B), and 5(C) are diagrams illustrating a relationship between a value of a vibration waveform and a suspension control value. FIGS. 6(A), 6(B), and 6(C) are diagrams illustrating a relationship between the vibration waveform and a time width. FIGS. 7(A) and 7(B) are a flowchart illustrating processing in the electronic control device according to a first embodiment and a diagram illustrating an input specification. FIGS. 8(A) and 8(B) are diagrams illustrating an example of a control value calculation unit according to a second embodiment and a storage unit. FIG. 9 is a configuration diagram of a training system according to the second embodiment that creates train data of a neural network. FIGS. 10(A) and 10(B) are a flowchart illustrating processing in an electronic control device according to the second embodiment and a diagram illustrating an input specification. FIG. 11 is a diagram illustrating an example of a control value calculation unit according to a third embodiment. FIGS. 12(A) and 12(B) are graphs for describing a modification of the control value calculation unit according to the third embodiment and prediction of a reached vibration waveform from an actual measured value. FIG. 13 is a configuration diagram of a training system according to the third embodiment that creates train data of a neural network. FIGS. 14(A) and 14(B) are a flowchart illustrating processing in an electronic control devi