JP3301346B2 - Rear wheel steering control device for trailer towing vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel steering control device incorporated in a trailer towing vehicle capable of steering a front wheel and a rear wheel, and more particularly to a turning control while preventing an excessive connection angle between the towing vehicle and the trailer. The present invention relates to a rear-wheel steering control device for a trailer-towed vehicle, which can be simplified and can enhance the steering performance at the time of a U-turn in a narrow place.

[0002]

2. Description of the Related Art One of large vehicles is a trailer towing vehicle. This trailer towing vehicle includes a towing vehicle 1 and a trailer 2 connected to the towing vehicle 1 as illustrated in FIG. 1, and is operated by operating the towing vehicle 1 so as to tow a trailer 2 that forms a bed. Be composed. FIG.
3 is the front wheel of the towing vehicle 1, 4 is the rear wheel, 5 is the wheel of the trailer 2, and 6 is the towing vehicle 1 and the trailer 2.
It is a connection part with.

The turning of the trailer towing vehicle is performed by steering the front wheels 3 of the towing vehicle 1 as shown in FIG. 2, and the trailer 2 is towed by the towing vehicle 1 with the turning operation of the towing vehicle 1. While turning. Because of this,
When turning at a large angle at an intersection or the like, a large deviation occurs between the turning trajectory of the towing vehicle 1 and the turning trajectory of the trailer 2, so that the towing vehicle 1 is steered while considering the turning trajectory of the trailer 2. Is required, and skilled steering technology is required.

[0004]

The problem to be solved by the invention
No. 56180 discloses that the front wheel 3 and the rear wheel 4 of the towing vehicle 1 are configured to be steerable (4WS), and the rear wheel 4 is turned in a direction opposite to the steering direction of the front wheel 3 of the towing vehicle 1 during low-speed running.
A technique for achieving a small turning by controlling the steering of the vehicle is disclosed.

However, if the rear wheels 4 are steered in the opposite phase to the front wheels 3 during low-speed running turning, the turning radius of the towing vehicle 1 itself can be reduced.
The angle of connection with the shaft tends to be excessively large, and a so-called jackknife phenomenon occurs, which may hinder the turning itself. Therefore, even if the rear wheels 4 can be steered, it is necessary to steer the front wheels 3 of the towing vehicle 1 while considering the turning trajectory of the trailer 2 to be towed and the connection angle with the trailer 2. Technology is required. In particular, when trying to make a U-turn in a limited space, generally, the steering angle of the front wheels 3 is easily set to the maximum, so that the above-described problem occurs remarkably.

The present invention has been made in view of such circumstances, and an object of the present invention is to prevent the connecting angle between a towing vehicle and a trailer from being excessively increased even when making a U-turn in a narrow place. It is an object of the present invention to provide a rear-wheel steering control device for a trailer-towed vehicle capable of facilitating turning and eventually improving the steering performance.

[0007]

In order to achieve the above object, a rear wheel steering control device for a trailer towed vehicle according to the present invention is incorporated in a trailer towed vehicle capable of steering front and rear wheels. Means for detecting a connection angle between the towing vehicle and the trailer, and turning control means for steering the rear wheels of the towing vehicle in the same direction as the front wheels when the connection angle detected by the means is equal to or greater than a predetermined value. It is characterized by having.

That is, when the connection angle is equal to or larger than a predetermined value, the rear wheels of the towing vehicle are steered in the same direction as the front wheels thereof. Even in the case where the pulled state continues, the trailer is towed while the connecting angle between the towed vehicle and the trailer is prevented from becoming excessive, thereby smoothing the turn.

According to a second aspect of the present invention, in the turning control means, when a connection angle between the towing vehicle and the trailer is less than the predetermined value, the rear wheel of the towing vehicle is held at a neutral position. It is characterized by ensuring highly natural steering characteristics during normal running except when turning at a large angle, and eliminating discomfort. Further, as set forth in claim 3, in the turning control means, the connection angle between the towing vehicle and the trailer is ψ, the interaxle distance between the front wheel axle and the rear wheel axle of the towing vehicle is L1, The distance from the connection point with the trailer to the axle of the trailer is L2,
When the offset distance between the rear wheel axle of the towing vehicle and the connection point between the trailer and the trailer is S, δr = tan ⁻¹ A A = [(L2−Scosψ) tanδf−L1sinψ] / [L2 + L1co
sψ−Scosψ], and the steering angle δr of the rear wheel is obtained to perform steering control of the rear wheel of the towing vehicle, thereby realizing a smooth turn.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rear wheel steering control device according to one embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 3 is a functional block diagram showing a schematic configuration of the rear wheel steering control device according to this embodiment. Basically, a vehicle speed sensor 11 for detecting a traveling speed v of the trailer towing vehicle, the towing vehicle 1 and the trailer 2, And a steering angle sensor 13 for detecting the steering angle δf of the front wheels 3 related to the steering (steering operation) of the towing vehicle 1. The turning control unit 14 detects information (the traveling speed v,
Based on the connection angle ψ and the steering angle δf), for example, the steering control for the rear wheels 4 is executed in accordance with the processing procedure shown in FIG. 4, and the rear wheels 4 are steered by driving the rear wheel steering mechanism 15.

The steering control for the rear wheels 4 will be described. This process is started by first detecting the vehicle speed v [step S1]. If the detected vehicle speed v is U
It is determined whether or not the speed is low, for example, 15 km or less when turning at a relatively steep angle at a turn or an intersection [Step S2]. Incidentally, when the vehicle speed v exceeds the above-mentioned determination speed, it is determined that the vehicle is traveling normally, and the rear wheel 4 is held at the neutral position without being concerned with the steering angle δf of the front wheel 3 at that time. [Step S3].
In other words, since the vehicle does not turn at a steep angle during high-speed driving, in this case, by maintaining the neutral position of the rear wheel 4, the steering characteristics with high naturalness are maintained, and the uncomfortable feeling of the driving operation (steering) is eliminated. Improve maneuverability.

If it is confirmed that the vehicle speed v is lower than the predetermined judgment speed, a connection angle ψ between the towing vehicle 1 and the trailer 2 is detected (step S4). That is, when the front wheel 4 is steered at a low speed and the towing vehicle 1 turns, the trailer 2 turns while being towed by the towing vehicle 1 in association with the turning, so that the connection 6 between the towing vehicle 1 and the trailer 2 The connection angle ψ changes gradually. Note that this connection angle 求 め is obtained as an inclination (intersection angle) between the longitudinal axis direction of the towing vehicle 1 and the longitudinal axis direction of the trailer 2. Therefore, when the towing vehicle 1 and the trailer 2 are aligned in a straight line toward the front in the traveling direction (when the axial directions are aligned), the connection angle ψ is defined as zero (0).

When the connection angle の between the towing vehicle 1 and the trailer 2 is detected, it is determined whether or not the connection angle ψ has reached a predetermined angle］ th [step S5].
This determination is made by determining whether or not the connection angle 達 has reached a predetermined connection angle 所 定 th at which the trailer-towing vehicle can be turned without causing a problem such as an excessive connection angle in a narrow place. Done. In other words, the above-described determination angle ψth is determined to be such that steering the rear wheel 4 in the same phase as the front wheel 3 prevents the coupling angle ψ from becoming excessive while maintaining the naturalness of the steering, and achieves a smooth turn. Set as corners. When it is confirmed by this determination that the connection angle ψ has not reached the connection angle に よ り th, for example, it is determined that a situation where a sharp turn is performed is not performed, and as described above, the rear wheel 4 is held as it is. It is held at the neutral position [Step S3].

On the other hand, when the connection angle ψ has reached the predetermined connection angle ψth, the vehicle turns at a sharp angle such as a U-turn at a low speed in conjunction with the above-described determination of the vehicle speed v. Is determined. In this case, first, a steering angle δf of the front wheels 3 is detected in accordance with a steering operation (steering) of the towing vehicle 1 [Step S6]. Then, based on the detected steering angle δf of the front wheel 3, a steering angle δr with respect to the rear wheel 4 is calculated as described later to facilitate the turning [step S 7].

This calculation is based on the front wheel 3 and the rear wheel 4 of the towing vehicle 1.
Is the distance between the axles of the trailer 2 and the axle 5 of the trailer 2 is L2.
And when the offset distance between the axle of the rear wheel 4 of the towing vehicle 1 and the connecting portion 6 with the trailer 2 is S,
As will be described later, δr = tan ^-1 [(L2−Scosψ) tanδf−L1sinψ] / [L2
+ L1cos {−Scos}]. However, the distance L1 between the axles, the distance L2 between the connection point 6 and the axle 5, and the offset distance S between the rear wheel axle 3 and the connection point 6 in the towing vehicle 1 are given as intrinsic values (constants) of the trailer towing vehicle. In practice, the calculation may be performed using the front wheel steering angle δf and the connection angle ψ as parameters.

When the steering angle δr of the rear wheel 4 is calculated, the rear wheel steering mechanism 1 is calculated according to the steering angle δr.
5, the rear wheels 4 of the towing vehicle 1 are steered in the same phase as the front wheels 3 by the steering angle δr (step S8). That is, the steering angle δr for the rear wheel 4 is determined according to the steering angle δf of the front wheel 3 and the connection angle ψ at that time, and the steering control for the rear wheel 4 is executed.

At this time, the steering amount δr of the rear wheel 4 is based on the connection angle ψ and the steering angle δf of the front wheel 3 as shown in FIG. 5, and the turning center O (xo,
yo), and is calculated as a condition for realizing a smooth turning with reference to the turning center O. That is, at the position (xo, yo) of the turning center O when the front wheel 3 is steered to make a turn with respect to the front wheel 3, the steering angle of the front wheel 3 is δf. When the connection angle is ψ, it is indicated by the intersection of a line segment a perpendicular to the direction of the front wheel 3 and a line segment f perpendicular to the direction of the wheel 5 of the trailer 2. In this case, the front wheel 3
Tan δf = yo / xo (1) between the steering angle δf and the position (xo, yo) of the turning center O. Where xo = x1 + L2sinψ, yo = L1−S + L2cosψ−y
X1 and y1 in the above equation have a relationship of tanψ = y1 / x1. Therefore, the relationship between xo and yo is as follows: tan = (L1−S + L2cosψ−yo) / (xo−L2sinψ) (xo−L2sinψ) tanψ = (L1−S + L2cosψ−yo) yo = − (xo−L2sinψ) tanψ + L1−S + L2sψ 2) can be arranged as

By the way, when the positions xo and yo of the turning center O are obtained based on the above equations (1) and (2), xo = [L2 (tanψsinψ + cosψ) + L1-S] / (tanδf + tanψ) = (L2 / cosψ + L1-S) / (Tanδf + tanψ) (3) yo = [L2 (tanψsinψ + cosψ) + L1-S] tanδf / (tanδf + tanψ) = (L2 / cosψ + L1-S) tanδf / (tanδf + tanψ) (4)

On the other hand, in order to realize a smooth turn of the trailer-towed vehicle while keeping the connection angle 一定 constant with respect to the turning center O, a line segment e connecting the rear wheel 4 and the turning center O is required. In this case, the rear wheels 4 may be steered in a right angle direction. That is, the rear wheel steering angle δr may be determined so as to satisfy the relationship of tanδr = (yo−L1)] / xo. Therefore, by substituting the above equations (3) and (4) into the above equation, tanδr = [[L2 + (L1−S) cosψ)] tanδf− [tanδf + tanψ] L1cosψ] / [L2 + L1cosψ−Scosψ] = [(L2− Scosψ) tanδf−L1sinψ] / [L2 + L1cosψ−Scosψ], and the steering angle δr of the rear wheel 4 becomes δr = tan ⁻¹ [(L2−Scosψ) tanδf−L1sinψ] / [L2 +
L1cosψ−Scosψ].

Thus, the steering angle δ of the front wheel 3 is thus obtained.
f and the connection angle 牽 between the towing vehicle 1 and the trailer 2 at that time
According to the present apparatus that controls the rear wheels 4 to the steering angle δr based on the above, for example, in a case where a U-turn is performed in a limited space, the state where the front wheels 3 are steered to the maximum steering angle δfm is continued. In such a case, the steering angle of the rear wheel 4 is controlled so that the connection angle と between the towing vehicle 1 and the trailer 2 does not exceed the optimum connection angle ψm.

FIG. 6A shows the case where the rear wheel 4 is steered by the present apparatus, and FIG. 6B shows the case where the front wheel 3 is properly steered by a skilled driver without steering the rear wheel 4. Further, FIG. 7 (c) shows the front wheels 3, the rear wheels 4 when the front wheels 3 are turned while maintaining the maximum steering angle δfm without steering the rear wheels 4.
(Connection point 6) and the movement locus of the wheel 5 are shown in comparison. In particular, ● indicates that the front wheel 3 is at the maximum steering angle δfm, 、 indicates that the connection angle ψ has reached the predetermined connection angle 所 定 th, and ■ indicates that the connection angle ψ has exceeded the limit connection angle ψm. Is shown.

As shown in FIG. 6, according to the steering control of the rear wheel 4 by the present apparatus, it is possible to realize a turn as smooth as a turn by a skilled driver. In addition, even if the vehicle continues turning while maintaining the front wheel 3 at the maximum steering angle δfm, the connection angle の between the towing vehicle amount 1 and the trailer 2 does not become excessively large as shown in FIG. Turning can be realized. Therefore, in the case of making a U-turn in a narrow place, even if the front wheel 3 is steered to the maximum steering angle δfm in order to realize a small turn as a driver's psychology, the turning operation is effectively assisted. In addition, it is possible to realize a sharp turn under appropriate rear wheel steering. In other words, it is possible to realize an effective turning without requiring the driver to have a skilled steering technique, and to easily turn at a steep angle.

The present invention is not limited to the above embodiment. For example, instead of determining the condition for starting rear wheel steering based on the connection angle の between the towing vehicle 1 and the trailer 2, the front wheel steering angle δf is equal to or greater than a predetermined steering angle, and the connection angle is equal to or greater than a predetermined value. May be set as the start condition of the steering control. Further, the control gain may be varied according to the front wheel steering angle Δf. In short, the steering of the front wheels 3 and the towing vehicle 1 during turning
Rear wheel 4 so that the connection angle の between the
May be controlled by steering. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0024]

As described above, according to the present invention, the connection angle between the towing vehicle and the trailer is detected, and when the connection angle is greater than a predetermined value, the rear wheels of the towing vehicle are steered in the same direction as the front wheels. Characterized in that it is provided with turning control means for performing the turning operation. Therefore, when the connection angle is equal to or larger than a predetermined value, the rear wheels of the towing vehicle are steered in the same direction as the front wheels thereof. Even in a case where the vehicle is steered to a corner, the vehicle can smoothly turn while preventing the connection angle from becoming excessively large.

When the connection angle is less than the predetermined value, it is necessary to hold the rear wheel of the towing vehicle at the neutral position. And operation (steering) without a sense of incongruity is possible. In particular, the connecting angle between the towing vehicle and the trailer is ト レ ー, the interaxle distance between the front wheel axle and the rear wheel axle of the towing vehicle is L1, and the connecting point between the towing vehicle and the trailer is When the distance of the trailer to the axle is L2 and the offset distance between the rear wheel axle of the towing vehicle and the connection point between the trailer and the trailer is S, δr = t
an ^-1 [(L2-Scosψ) tanδf-L1sinψ] / [L2 + L1cos
Since the steering angle δr of the rear wheel is obtained as {−Scos}] and the steering of the rear wheel of the towing vehicle is controlled, an appropriate steering angle can be given to the rear wheel to realize a smooth turning.

Therefore, even in the case of making a U-turn in a narrow place, it is possible to prevent the connecting angle between the towing vehicle and the trailer from becoming too large to facilitate turning, and to improve the steering performance. A great effect can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a trailer towing vehicle.

FIG. 2 is a diagram showing a turning state of a trailer-towing vehicle.

FIG. 3 is a functional block diagram showing a schematic configuration of a rear wheel steering control device according to one embodiment of the present invention.

FIG. 4 is a diagram showing a schematic control procedure of rear wheel steering control according to one embodiment of the present invention.

FIG. 5 is a schematic diagram for analyzing a rear wheel steering angle with respect to a front wheel steering angle and a connection angle in a trailer-tracted vehicle.

FIG. 6 is a diagram showing a turning characteristic when rear wheel steering according to the present invention is performed and a turning characteristic when rear wheel steering is not performed;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Towing vehicle 2 Trailer 3 Front wheel 4 Rear wheel 5 Wheel 6 Connection part (connection point) 11 Vehicle speed sensor 12 Connection angle sensor 13 Steering angle sensor 14 Turning control part 15 Rear wheel steering mechanism

Claims (3)

(57) [Claims] 1. A rear-wheel steering control device incorporated in a trailer-towed vehicle in which front wheels and rear wheels can be steered, wherein a means for detecting a connection angle between the towed vehicle and the trailer, and wherein the detected connection angle is a predetermined value A turning control means for steering a rear wheel of the towing vehicle in the same direction as a front wheel, wherein a rear wheel steering control device for a trailer towing vehicle is provided. 2. The vehicle according to claim 1, wherein the turning control unit holds the rear wheel of the towing vehicle at a neutral position when a connection angle between the towing vehicle and the trailer is less than the predetermined value. A rear wheel steering control device according to the above-mentioned trailer towing vehicle. 3. The turning control means includes: a connection angle between the towing vehicle and the trailer; を, an interaxle distance between a front wheel axle and a rear wheel axle of the towing vehicle; L1, a connection point between the towing vehicle and the trailer; Where L2 is the distance from the trailer to the axle of the trailer, and S is the offset distance between the rear wheel axle of the towing vehicle and the connection point of the trailer. Δr = tan ⁻¹ A A = [(L2−Scosψ) tanδf−L1sinψ] / [L2 + L1co
2. The rear wheel steering control device according to claim 1, wherein a steering angle δr of the rear wheel is obtained as sψ−Scosψ], and the rear wheel of the tow vehicle is steered.