JP2021017150A - Suspension control device - Google Patents

Abstract

To appropriately prevent a vehicle from rolling over during steep turn.SOLUTION: A control device 10 for controlling a pair of suspensions 6a, 6b which can adjust the vehicle height of a vehicle body 2 comprises: a vehicle information acquisition unit 32 acquiring a steering angle and a steering angle velocity while a vehicle 1 travels; a turning estimation unit 34 estimating whether a turning radius of a vehicle 1 right after becomes smaller than a prescribed value on the basis of the steering angle and the steering angle velocity; and a suspension control unit 36 controlling the suspensions 6a, 6b in such a way that the vehicle height on a turning outer side of the vehicle 1 is increased when estimating that the turning radius becomes smaller than the prescribed value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a suspension control device that controls a suspension provided in a vehicle.

Some vehicles are equipped with an air suspension whose height can be adjusted. The vehicle controls the air suspension so that the vehicle is in a horizontal posture, for example, when the running vehicle is tilted.

Japanese Unexamined Patent Publication No. 2013-154834

By the way, the vehicle may make a sharp turn such as a right turn at an intersection, and the vehicle tilts under the action of centrifugal force during the sharp turn. Since the sharp turn is performed in a short time, the conventional suspension control that puts the vehicle in the horizontal posture cannot make the vehicle in the horizontal posture during the sharp turn, and the vehicle may roll over during the sharp turn.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to appropriately prevent the vehicle from rolling over during a sharp turn.

In one aspect of the present invention, it is a suspension control device provided on both sides in the axial direction between the axle and the vehicle body and controlling a pair of suspensions capable of adjusting the vehicle height of the vehicle body, and the vehicle is running. An acquisition unit that acquires the steering angle and the steering angle speed of the vehicle, an estimation unit that estimates whether or not the turning radius of the vehicle immediately after the vehicle is smaller than a predetermined value based on the steering angle and the steering angle speed, and the turning. Provided is a suspension control device including a control unit that controls the suspension so as to increase the vehicle height on the outer side of the turning of the vehicle when the radius is estimated to be smaller than the predetermined value.

Further, the estimation unit may estimate that the turning radius becomes smaller than the predetermined value when the steering angle is larger than the first threshold value and the steering angular velocity is larger than the second threshold value.

Further, the acquisition unit further acquires the weight of the vehicle, and the suspension control device provides a threshold adjustment unit that adjusts the magnitudes of the first threshold value and the second threshold value according to the magnitude of the weight. It may be further prepared.

Further, the acquisition unit further acquires the vehicle speed of the vehicle, and the suspension control device provides a threshold value adjustment unit that adjusts the magnitudes of the first threshold value and the second threshold value according to the magnitude of the vehicle speed. It may be further prepared.

Further, when the turning radius is estimated to be smaller than the predetermined value, the control unit may increase the spring constant of the suspension on the outer side of the turning of the pair of suspensions.

According to the present invention, there is an effect that the vehicle can be appropriately prevented from rolling over during a sharp turn.

It is a block diagram for demonstrating an example of the structure of a vehicle 1. It is a schematic diagram for demonstrating the posture at the time of turning of the vehicle 900 which concerns on a comparative example. It is a schematic diagram for demonstrating the 1st threshold value of a steering angle and the 2nd threshold value of a steering angular velocity. It is a schematic diagram for demonstrating the operation example of suspensions 6a, 6b. It is a flowchart which shows the operation example of the control device 10 at the time of turning.

<Vehicle configuration>
The configuration of the vehicle equipped with the suspension control device according to the embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram for explaining an example of the configuration of the vehicle 1. The vehicle 1 is a truck as an example. As shown in FIG. 1, the vehicle 1 has a detection device 4, a suspension device 6, and a control device 10.

The detection device 4 detects the state of the moving vehicle 1. For example, the detection device 4 has a steering angle sensor that detects the steering angle of the moving vehicle 1. Further, the detection device 4 has a weight sensor that detects the weight of the vehicle 1 and a vehicle speed sensor that detects the vehicle speed of the vehicle 1. The detection device 4 outputs the detection result to the control device 10.

The suspension device 6 has a pair of suspensions 6a and 6b provided on both sides in the axial direction between the axle and the vehicle body. The suspensions 6a and 6b are, for example, active suspensions that can be expanded and contracted while the vehicle 1 is traveling. The suspensions 6a and 6b also have a function of adjusting the vehicle height of the vehicle body. The suspensions 6a and 6b are air suspensions that utilize air pressure here, but are not limited thereto, and may be other active suspensions that utilize hydraulic pressure, for example.

The control device 10 controls the operations of the detection device 4 and the suspension device 6. The control device 10 has a function of a suspension control device that controls the suspension device 6. For example, the control device 10 controls the suspension device 6 based on the detection result of the detection device 4.

By the way, when the vehicle 1 turns at an intersection or the like, the posture of the vehicle 1 is tilted. Hereinafter, the vehicle 900 according to the comparative example shown in FIG. 2 will be described as an example.
FIG. 2 is a schematic view for explaining the posture of the vehicle 900 according to the comparative example when turning. Here, as shown in FIG. 2A, it is assumed that the vehicle 900 turns with a turning radius R (distance between the turning center C and the center of the vehicle 900). At this time, the vehicle 900 is normally in an inclined posture (a state in which the vehicle height on the outer side in the radial direction is low) as shown in FIG. 2 (b). Then, the centrifugal force F acts on the vehicle 900 in an inclined posture while turning. When the turning radius R is small (that is, a sharp turn), the vehicle 900 in an inclined posture may roll over in the radial direction due to the action of the centrifugal force F.

On the other hand, the vehicle 1 according to the present embodiment will be described in detail later, but before the start of turning (or immediately after the start of turning), the pair of suspensions 6a and 6b are located outward in the radial direction at the time of turning. By operating the suspension to raise the vehicle height outward in the radial direction of the vehicle 1, the posture of the vehicle 1 tilted during turning is made horizontal. As a result, it is possible to prevent the vehicle 1 from being tilted during turning, so that the vehicle 1 can be prevented from rolling over.

<Detailed configuration of control device>
The detailed configuration of the control device 10 which is the suspension control device will be described with reference to FIG. As shown in FIG. 1, the control device 10 has a storage unit 20 and a control unit 30.

The storage unit 20 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 20 stores programs and various data for execution by the control unit 30. Further, the storage unit 20 stores information such as a threshold value used for estimating the turning state of the vehicle 1.

The control unit 30 is, for example, a CPU (Central Processing Unit). The control unit 30 performs processing related to the vehicle 1 by executing the program stored in the storage unit 20. As shown in FIG. 1, the control unit 30 functions as a vehicle information acquisition unit 32, a turn estimation unit 34, a suspension control unit 36, and a threshold value adjustment unit 38.

The vehicle information acquisition unit 32 acquires the traveling information of the vehicle 1. For example, the vehicle information acquisition unit 32 acquires the steering angle and steering angular velocity of the vehicle 1 while the vehicle is traveling. Specifically, the vehicle information acquisition unit 32 acquires the steering angle detected by the detection device 4 (for example, the steering angle sensor). Further, the vehicle information acquisition unit 32 obtains the steering angular velocity from the acquired steering angle.

Further, the vehicle information acquisition unit 32 acquires information regarding the state of the vehicle 1. For example, the vehicle information acquisition unit 32 may further acquire the weight and vehicle speed of the vehicle 1. Specifically, the vehicle information acquisition unit 32 acquires the weight detected by the detection device 4 (for example, a weight sensor). Further, the vehicle information acquisition unit 32 acquires the vehicle speed detected by the detection device 4 (for example, the vehicle speed sensor).

The turning estimation unit 34 estimates the turning state of the vehicle 1. For example, the turning estimation unit 34 estimates the turning state before the start of turning (or immediately after the start of turning) when the vehicle 1 turns at an intersection or the like. Specifically, the turning estimation unit 34 estimates the turning state based on the steering angle and the steering angular velocity acquired by the vehicle information acquisition unit 32. At this time, the turning estimation unit 34 estimates whether or not the turning radius becomes smaller than a predetermined value (that is, makes a sharp turn).

For example, the turning estimation unit 34 estimates that the turning radius of the vehicle 1 becomes smaller than a predetermined value when the steering angle is larger than the first threshold value and the steering angular velocity is larger than the second threshold value. The turning estimation unit 34 estimates whether or not the vehicle 1 makes a sharp turn based on both the steering angle and the steering angular velocity, so that the estimation is made as compared with the case where only one of the steering angle and the steering angular velocity is estimated. The accuracy can be improved. That is, if the estimation is based only on the steering angle, a gentle curve or the like may be erroneously detected. Further, when the estimation is made only by the steering angular velocity, for example, the behavior of the vehicle 1 for avoiding an obstacle on the road surface may be erroneously detected.

FIG. 3 is a schematic diagram for explaining the first threshold value of the steering angle and the second threshold value of the steering angular velocity. Here, the steering angle threshold value A1 corresponds to the first threshold value, and the steering angular velocity threshold value B1 corresponds to the second threshold value. The turning estimation unit 34 estimates that the vehicle 1 makes a sharp turn when the steering angle is larger than the threshold value A1 and the steering angular velocity is larger than the threshold value B1 (the hatched region in FIG. 3).

When the turning radius of the vehicle 1 is estimated to be smaller than a predetermined value, the suspension control unit 36 controls the suspensions 6a and 6b so as to raise the vehicle height on the outer side of the turning of the vehicle 1. For example, the suspension control unit 36 operates the suspension of one of the suspensions 6a and 6b to raise the vehicle height on the outer side of the turning of the vehicle 1.

FIG. 4 is a schematic diagram for explaining an operation example of the suspensions 6a and 6b. The suspensions 6a and 6b have springs 7a and 7b, respectively. The springs 7a and 7b are air springs provided between the vehicle body 2 and the axles 3 of the wheels 8a and 8b, and are expandable and contractible. Here, it is assumed that the vehicle 1 turns around the turning center C. The suspension control unit 36 supplies air to the spring 7a on the outer side in the radial direction to extend the spring 7a. As a result, the vehicle body 2 is in a posture of being tilted diagonally to the right (tilted so that the vehicle height on the outer side is high). When the vehicle body 2 is tilted in this way, the vehicle 1 makes a sharp turn immediately afterwards and tilts in the opposite direction (see FIG. 2B), resulting in a state close to horizontal.

When the turning radius of the vehicle 1 is estimated to be smaller than a predetermined value, the suspension control unit 36 has a spring constant of the suspension on the outer side of turning (suspension 6a in FIG. 4) of the pair of suspensions 6a and 6b. May be increased. Specifically, the suspension control unit 36 increases the spring constant of the spring 7a of the suspension 6a. As a result, the spring 7a is less likely to contract during the sharp turn of the vehicle 1 immediately after, so that the vehicle 1 can be prevented from being in the posture shown in FIG. 2 (b).

The threshold value adjusting unit 38 adjusts the first threshold value and the second threshold value used by the turning estimation unit 34. The threshold value adjusting unit 38 may adjust the sizes of the first threshold value and the second threshold value according to the weight of the vehicle 1. For example, the threshold value adjusting unit 38 reduces the size of the first threshold value and the second threshold value as the weight of the vehicle 1 increases. Similarly, the threshold value adjusting unit 38 may adjust the magnitudes of the first threshold value and the second threshold value according to the magnitude of the vehicle speed of the vehicle 1. For example, the threshold value adjusting unit 38 reduces the magnitudes of the first threshold value and the second threshold value as the vehicle speed of the vehicle 1 increases. Specifically, when the weight or vehicle speed of the vehicle 1 increases, the threshold adjusting unit 38 reduces the steering angle threshold A1 to the threshold A2 (FIG. 3) and sets the steering angular velocity threshold B1 to the threshold B2 (FIG. 3). Make it smaller.

When the threshold value adjusting unit 38 adjusts the threshold value, the turning estimation unit 34 estimates whether or not the vehicle 1 makes a sharp turn using the adjusted threshold value. As a result, the optimum threshold value can be set according to the state of the vehicle 1, so that it is possible to estimate with high accuracy whether or not the vehicle 1 makes a sharp turn.

<Example of operation of control device during turning>
An operation example of the control device 10 when the vehicle 1 is turning will be described with reference to FIG.

FIG. 5 is a flowchart showing an operation example of the control device 10 during turning. Here, the flowchart of FIG. 5 starts from the point where the vehicle 1 starts traveling.

First, the vehicle information acquisition unit 32 of the control unit 30 acquires the steering angle and the steering angular velocity of the running vehicle 1 (step S102). Specifically, the vehicle information acquisition unit 32 acquires the steering angle detected by the steering angle sensor of the detection device 4. Further, the vehicle information acquisition unit 32 obtains the steering angular velocity from the acquired steering angle.

Next, the turning estimation unit 34 estimates the turning state of the vehicle 1 immediately after based on the acquired steering angle and steering angular velocity (step S104). Specifically, the turn estimation unit 34 estimates whether or not the vehicle 1 makes a sharp turn.

Then, when the vehicle 1 is estimated to make a sharp turn (step S106: Yes), that is, when the vehicle 1 is estimated to turn immediately after, the suspension control unit 36 is on the outer side of the turn of the vehicle 1. The suspensions 6a and 6b are controlled so as to raise the vehicle height (step S108). Specifically, when it is estimated that the vehicle 1 makes a sharp turn around the turning center C as shown in FIG. 4, the suspension 6a is extended and the vehicle on the outer side of the turning is raised before the start of the sharp turning. To do. The suspension 6a may be extended immediately after the start of the sharp turn, not before the start.
On the other hand, if it is not estimated that the vehicle 1 makes a sharp turn (step S106: No), the suspension control unit 36 does not control step S108.

<Effect in this embodiment>
The control device 10 of the above-described embodiment estimates whether or not the turning radius of the vehicle 1 immediately after is smaller than a predetermined value (that is, making a sharp turn) based on the steering angle and the steering angular velocity of the vehicle 1. When it is estimated that the vehicle 1 makes a sharp turn, the control device 10 controls the suspensions 6a and 6b (suspension 6a in FIG. 4) so as to raise the vehicle height on the outer side of the turning of the vehicle 1.
As a result, before the start of the sharp turn of the vehicle 1 (or immediately after the start of the sharp turn), the vehicle height on the outer side of the turn of the vehicle 1 becomes high. When the vehicle 1 makes a sharp turn immediately after that, even if the vehicle 1 tilts from the posture, the vehicle 1 is in a state close to horizontal, so that the vehicle 1 can be prevented from rolling over.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. is there. For example, all or a part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination has the effect of the original embodiment.

1 Vehicle 2 Body 3 Axles 6a, 6b Suspension 10 Control device 32 Vehicle information acquisition unit 34 Turn estimation unit 36 Suspension control unit 38 Threshold adjustment unit

Claims (5)

A suspension control device that is provided on both sides in the axial direction between the axle and the vehicle body and controls a pair of suspensions capable of adjusting the vehicle height of the vehicle body.
An acquisition unit that acquires the steering angle and steering angular velocity while the vehicle is running,
An estimation unit that estimates whether or not the turning radius of the vehicle immediately after is smaller than a predetermined value based on the steering angle and the steering angular velocity.
When the turning radius is estimated to be smaller than the predetermined value, a control unit that controls the suspension so as to raise the vehicle height on the outer side of the turning of the vehicle.
Suspension control device. The estimation unit estimates that the turning radius becomes smaller than the predetermined value when the steering angle is larger than the first threshold value and the steering angular velocity is larger than the second threshold value.
The suspension control device according to claim 1. The acquisition unit further acquires the weight of the vehicle.
Further, a threshold value adjusting unit for adjusting the size of the first threshold value and the second threshold value according to the size of the weight is provided.
The suspension control device according to claim 2. The acquisition unit further acquires the vehicle speed of the vehicle, and obtains the vehicle speed.
A threshold adjusting unit for adjusting the magnitudes of the first threshold value and the second threshold value according to the magnitude of the vehicle speed is further provided.
The suspension control device according to claim 2 or 3. When the turning radius is estimated to be smaller than the predetermined value, the control unit increases the spring constant of the suspension on the outer side of the turning of the pair of suspensions.
The suspension control device according to any one of claims 1 to 4.