Suspension control device for vehicle

Patent metadata

Field	Value
Publication number	US-9884532-B2
Application number	US-201615281194-A
Country	US
Kind code	B2
Filing date	Sep 30, 2016
Priority date	Oct 7, 2015
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

A suspension control device includes an actuator configured to change an up/down stroke of a suspension, a front sensor, and a control device configured to estimate a displacement in a vertical direction of a road surface based on a detection result of the front sensor, thereby controlling the actuator. When the control device determines that a step portion in which a wheel comes into contact with two points of the road surface viewed in a direction along a rotational axis of the wheel exists ahead of a vehicle, the control device controls a force generated by the actuator so that, when the wheel comes into contact with the two points, the wheel rolls about the point without substantially pressing the point toward the travel direction of the vehicle.

First claim

What is claimed is:

1. A suspension control device for a vehicle, comprising:
an actuator configured to change an up/down stroke of a suspension for suspending a wheel from a vehicle body;
a prediction device configured to predict an undulation of a road surface ahead of the vehicle; and
a control device configured to estimate a displacement in a vertical direction of the road surface based on a result of the prediction by the prediction device, and control the actuator so that the up/down stroke of the suspension changes depending on a displacement in a vertical direction of the road surface,
wherein the control device is configured to, when an undulation of the road surface that generates a state where the wheel comes into contact with two portions of the road surface in a direction viewed along a rotational axis of the wheel, and in which a leading portion in the travel direction of the vehicle out of the two portions is higher than the other portion is determined to exist on the road surface ahead of the vehicle, control the up/down stroke of the suspension through the control of the actuator so that, when the wheel comes into contact with the two portions, the wheel rolls about the leading portion while maintaining a state of the contact with the leading portion without substantially pressing the leading portion toward the travel direction of the vehicle, and
wherein the control device is configured to set a target trajectory of a predetermined position of the wheel and to control the up/down stroke of the suspension through the control of the actuator so that the predetermined position of the wheel moves along the target trajectory when the wheel comes into contact with the two portions.

2. The suspension control device for a vehicle according to claim 1 , wherein the control device is configured to set the target trajectory as a trajectory in a Cartesian coordinate system that has as an origin the predetermined position at a time point set in advance between a time point at which the roughness is determined to exist on the road surface ahead of the vehicle and a time point at which the wheel comes into contact with the two portions of the road surface, the travel direction of the vehicle as a time axis, and the vertical direction as an up/down displacement of the predetermined position.

3. The suspension control device for a vehicle according to claim 2 , wherein the control device is configured to set the target trajectory based on a radius of the wheel, a difference in height between the two portions, a distance in the travel direction of the vehicle between the two portions, and a travel speed of the vehicle.

4. The suspension control device for a vehicle according to claim 1 , wherein the control device is configured to estimate a displacement in the vertical direction of the road surface after each predetermined period, set, when a plurality of estimated displacements exist between the two portions, at least one intermediate target point on the target trajectory between the two portions, and correct the target trajectory so that the target trajectory is a straight line connecting a start point of the target trajectory and an intermediate target point closest to the start point with each other between the start point and the intermediate target point closest to the start point.

5. The suspension control device for a vehicle according to claim 4 , wherein the control device is configured to set a plurality of intermediate target points, and correct the target trajectory so that the target trajectory is a straight line connecting two intermediate target points neighboring each other between the two intermediate target points neighboring each other.

6. The suspension control device for a vehicle according to claim 1 , wherein the control device is configured to estimate a displacement in the vertical direction of the road surface after each predetermined period, set, when a plurality of estimated displacements exist between the two portions, at least one intermediate target point on the target trajectory between the two portions, and correct the target trajectory so that the target trajectory is a straight line connecting an intermediate target point closest to an end point of the target trajectory and the end point of the target trajectory with each other between the intermediate target point closest to the end point and the end point.

7. The suspension control device for a vehicle according to claim 6 , wherein the control device is configured to set a plurality of intermediate target points, and correct the target trajectory so that the target trajectory is a straight line connecting two intermediate target points neighboring each other between the two intermediate target points neighboring each other.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tsuda Taishi

Classifications

• B60G2600/182

  Active control means · CPC title

• B60G2400/204

  Vehicle speed · CPC title

• B60G2500/30

  Height or ground clearance · CPC title

• B60G2400/82

  Ground surface · CPC title

• B60G2400/10

  Acceleration; Deceleration · CPC title