阅读说明：本技术 一种半挂汽车列车后视镜自动调节系统和方法 (Automatic adjusting system and method for rearview mirror of semi-trailer train ) 是由 徐晓美 秦勇杰 蔡浩浩 王雨婷 侯宇 朱铖伟 于 2021-09-27 设计创作，主要内容包括：本申请公开了一种半挂汽车列车后视镜自动调节系统和方法,本系统包括角度变阻模块、偏转计算模块和动作模块；角度变阻模块根据半挂汽车列车的牵引车与挂车的相对偏转角度,生成偏转电流信号；偏转计算模块根据偏转电流信号,生成偏转动作控制信号；动作模块根据偏转动作控制信号,控制半挂汽车列车的后视镜产生偏转动作。本方法包括根据半挂汽车列车的牵引车和挂车的相对偏转角度,产生偏转电流信号；根据偏转电流信号,生成偏转动作控制信号；根据偏转动作控制信号,控制半挂汽车列车的后视镜产生偏转动作。本申请仅通过牵引车与挂车之间的相对角度就能够改变后视镜的转动角度,不会影响驾驶员正常驾驶,有效保障了行车安全。(The application discloses an automatic adjusting system and method for a rearview mirror of a semi-trailer train, wherein the system comprises an angle variable resistance module, a deflection calculating module and an action module; the angle variable resistance module generates a deflection current signal according to the relative deflection angle of a tractor and a trailer of the semi-trailer train; the deflection calculation module generates a deflection action control signal according to the deflection current signal; the action module controls a rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal. The method comprises generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of the semi-trailer train; generating a deflection action control signal according to the deflection current signal; and controlling a rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal. This application only just can change the turned angle of rear-view mirror through the relative angle between tractor and the trailer, can not influence driver's normal driving, has effectively ensured driving safety.)

1. An automatic rearview mirror adjusting system for a semi-trailer train is characterized by comprising an angle variable resistance module, a deflection calculating module and an action module;

the angle variable resistance module is used for generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of the semi-trailer train;

the deflection calculating module is used for generating a deflection action control signal according to the deflection current signal;

the action module is used for controlling the rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal.

2. The automatic mirror adjustment system for a semi-trailer motor train according to claim 1, wherein the angle rheostat module comprises an annular base, a resistor ring, a slider, a traction pin and a dc power supply;

the resistance ring is wound on the periphery of the annular base body;

the annular base body is fixedly installed with the trailer through the traction pin;

the sliding block is fixedly installed with the tractor, and the sliding block is connected with the resistance coil in a sliding manner;

the direct current power supply is used for providing a direct current signal to the resistance coil;

one end of the direct current power supply is connected with one end of the resistance coil, and the other end of the direct current power supply and the sliding block are both connected with the deflection calculation module.

3. The automatic mirror adjustment system for a semi-trailer motor train as set forth in claim 2, wherein said resistive coil comprises a left resistive coil and a right resistive coil, said dc power source comprises a left power source and a right power source, and said deflection current signal comprises a left deflection current signal and a right deflection current signal;

the relative deflection angle comprises a left relative deflection angle and a right relative deflection angle;

one end of the left power supply is connected with one end of the left resistance ring, the other end of the left power supply is connected with the deflection calculation module, the left power supply, the left resistance ring, the sliding block and the deflection calculation module form a left current loop, and when the tractor and the trailer generate the left-direction relative deflection angle, the left current loop generates the left deflection current signal;

one end of the right power supply is connected with one end of the right resistance ring, the other end of the right power supply is connected with the deflection calculation module, the right power supply, the right resistance ring, the sliding block and the deflection calculation module form a right current loop, and when the tractor and the trailer generate the right relative deflection angle, the right current loop generates the right deflection current signal.

4. The automatic mirror adjustment system for a semi-trailer motor train according to claim 3, wherein said action module comprises a stepper drive control unit and a stepper motor;

the stepping drive control unit is used for generating stepping signals according to the deflection action control signals;

and the stepping motor controls the rearview mirror to generate deflection action according to the stepping signal.

5. The automatic mirror adjustment system for a semi-trailer motor train according to claim 4, wherein said stepper motors comprise a left stepper motor and a right stepper motor, said step signals comprise a left step signal and a right step signal, said mirror comprises a left mirror and a right mirror, said yaw motions comprise a left mirror yaw motion and a right mirror yaw motion;

the left stepping motor controls a left rearview mirror to generate a left rearview mirror deflection action according to the left stepping signal;

and the right stepping motor controls the right rearview mirror to generate the deflection action of the right rearview mirror according to the right stepping signal.

6. An automatic adjusting method for a rearview mirror of a semi-trailer train is characterized by comprising the following steps:

generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of the semi-trailer train;

generating a deflection action control signal according to the deflection current signal;

and controlling a rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal.

7. The automatic mirror adjustment method for a semi-trailer motor train according to claim 6, wherein the relative yaw angle comprises a left relative yaw angle and a right relative yaw angle;

the deflection current signals comprise a left deflection current signal and a right deflection current signal;

generating the left deflection current signal when the tractor and the trailer generate the left relative deflection angle;

generating the right deflection current signal when the tractor and the trailer generate the right relative deflection angle.

8. The method of claim 7, wherein the yaw motion includes a left mirror yaw motion and a right mirror yaw motion;

when the left deflection current signal is generated, the rearview mirror of the semi-trailer train generates the left rearview mirror deflection action;

and when the right deflection current signal is generated, the rearview mirror of the semi-trailer train generates the deflection action of the right rearview mirror.

Technical Field

The application belongs to the technical field of semi-trailer automobile train rearview mirror equipment, and particularly relates to an automatic semi-trailer automobile train rearview mirror adjusting system and method.

Background

The semi-trailer train has the advantages that the total length of the train body is large, the tractor and the trailer are connected in an articulated mode, and the cab is higher in position, so that a driver cannot observe the traffic condition near the rear end of the trailer in turning through the fixedly installed rearview mirror, namely, the semi-trailer train has a large visual field blind area in the turning process of the train. Relevant research shows that a large number of semi-trailer train traffic accidents are caused by the view blind area. To solve the blind field of view, follow-up mirror devices have been proposed, such as an adjustable multi-mirror combination, but although they can partially solve the blind field of view, they greatly increase wind noise and increase the visual burden on the driver. In order to solve the problem of insufficient visual field in the turning process of vehicles, a plurality of cameras are additionally arranged at the front end of the trailer, and a multi-window display is arranged in a cab, but the information of the multi-window display cameras enables a driver to often dazzle eyes and disturb the eyes, so that the driver is out of sight of the other, usually neglects the traffic condition in front while watching the display, and is not favorable for driving safety.

How to realize the automatic matching of the rearview mirror and the driving direction by only using the existing rearview mirror and automatically adjusting the rearview mirror becomes the research focus in the field.

Disclosure of Invention

The application provides a semi-mounted motor train rear-view mirror automatic regulating system and method, according to the relative angle between tractor and the trailer, through producing an angle signal, controls the automatic angular adjustment that produces of rear-view mirror, makes the angle of rear-view mirror and the relative angle phase-match between tractor and the trailer.

In order to achieve the above purpose, the present application provides the following solutions:

an automatic adjusting system for a rearview mirror of a semi-trailer train comprises an angle variable resistance module, a deflection calculating module and an action module;

the angle variable resistance module is used for generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of the semi-trailer train;

the deflection calculating module is used for generating a deflection action control signal according to the deflection current signal;

the action module is used for controlling the rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal.

Preferably, the angle variable resistance module comprises an annular base body, a resistance ring, a sliding block, a traction pin and a direct-current power supply;

the resistance ring is wound on the periphery of the annular base body;

the annular base body is fixedly installed with the trailer through the traction pin;

the sliding block is fixedly installed with the tractor, and the sliding block is connected with the resistance coil in a sliding manner;

the direct current power supply is used for providing a direct current signal to the resistance coil;

one end of the direct current power supply is connected with one end of the resistance coil, and the other end of the direct current power supply and the sliding block are both connected with the deflection calculation module.

Preferably, the resistance coil comprises a left resistance coil and a right resistance coil, the dc power supply comprises a left power supply and a right power supply, and the deflection current signal comprises a left deflection current signal and a right deflection current signal;

the relative deflection angle comprises a left relative deflection angle and a right relative deflection angle;

one end of the left power supply is connected with one end of the left resistance ring, the other end of the left power supply is connected with the deflection calculation module, the left power supply, the left resistance ring, the sliding block and the deflection calculation module form a left current loop, and when the tractor and the trailer generate the left-direction relative deflection angle, the left current loop generates the left deflection current signal;

one end of the right power supply is connected with one end of the right resistance ring, the other end of the right power supply is connected with the deflection calculation module, the right power supply, the right resistance ring, the sliding block and the deflection calculation module form a right current loop, and when the tractor and the trailer generate the right relative deflection angle, the right current loop generates the right deflection current signal.

Preferably, the action module comprises a stepping drive control unit and a stepping motor;

the stepping drive control unit is used for generating stepping signals according to the deflection action control signals;

and the stepping motor controls the rearview mirror to generate deflection action according to the stepping signal.

Preferably, the stepping motor comprises a left stepping motor and a right stepping motor, the stepping signal comprises a left stepping signal and a right stepping signal, the rear view mirror comprises a left rear view mirror and a right rear view mirror, and the deflection action comprises a left rear view mirror deflection action and a right rear view mirror deflection action;

the left stepping motor controls a left rearview mirror to generate a left rearview mirror deflection action according to the left stepping signal;

and the right stepping motor controls the right rearview mirror to generate the deflection action of the right rearview mirror according to the right stepping signal.

The application also discloses an automatic adjusting method of the rearview mirror of the semi-trailer automobile train, which comprises the following steps:

generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of the semi-trailer train;

generating a deflection action control signal according to the deflection current signal;

and controlling a rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal.

Preferably, the relative deflection angle includes a left-direction relative deflection angle and a right-direction relative deflection angle;

the deflection current signals comprise a left deflection current signal and a right deflection current signal;

generating the left deflection current signal when the tractor and the trailer generate the left relative deflection angle;

generating the right deflection current signal when the tractor and the trailer generate the right relative deflection angle.

Preferably, the yaw motion comprises a left rearview mirror yaw motion and a right rearview mirror yaw motion;

when the left deflection current signal is generated, the rearview mirror of the semi-trailer train generates the left rearview mirror deflection action;

and when the right deflection current signal is generated, the rearview mirror of the semi-trailer train generates the deflection action of the right rearview mirror.

The beneficial effect of this application does:

the application discloses an automatic adjusting system and method for a rearview mirror of a semi-trailer train, which is characterized in that a control system is added on the basis of the existing rearview mirror, and the rotation angle of the rearview mirror can be changed only through the relative angle between a tractor and a trailer, so that the visual field of the rearview mirror is changed; the application can not increase the wind noise of the rearview mirror and the visual burden of the driver, can not influence the normal driving of the driver, and effectively ensures the driving safety. The method and the device have wide popularization space and use value.

Drawings

In order to more clearly illustrate the technical solution of the present application, the drawings needed to be used in the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive exercise.

FIG. 1 is a schematic structural view of an automatic rearview mirror adjustment system for a semi-trailer train according to a first embodiment of the present application;

FIG. 2 is a schematic diagram of a semi-trailer train profile as set forth in one embodiment of the present application;

fig. 3 is a schematic view of static geometric parameters of a semi-trailer train in a situation one according to an embodiment of the present application, wherein (a) shows a schematic geometric relationship of a right rear view mirror with respect to a positive direction of a vehicle, and (b) shows a schematic geometric relationship of the right rear view mirror with respect to a lateral direction of the vehicle;

fig. 4 is a schematic diagram of the angular relationship between the trailer and the tractor of the semi-trailer train in a right-turn state in a first situation according to an embodiment of the present application, wherein (a) and (b) respectively show the angular relationship between the right rearview mirror and the driver in different turning angles;

fig. 5 is a right rearview mirror angle relationship of a semi-trailer train in a situation of a first embodiment of the present application, wherein (b) shows the angle α and the corresponding relationship of (a) the middle angles 5 and 6;

fig. 6 is a schematic view of static geometric parameters of a semi-trailer train in case two according to the first embodiment of the present application, wherein (a) shows a schematic view of a geometric relationship between a left rearview mirror and a positive direction of a vehicle, and (b) shows a schematic view of a geometric relationship between a left rearview mirror and a lateral direction of a vehicle;

fig. 7 is a schematic angle relationship diagram of the semi-trailer train in the second situation of the present application when the trailer and the tractor are turned left, wherein (a) and (b) respectively show the angle relationship diagram of the left rearview mirror relative to the driver at different turning angles;

fig. 8 is a left rear view mirror angle relationship of the semi-trailer train in case two according to the first embodiment of the present application, wherein (b) shows the angle α and the corresponding relationship between (a) the intermediate angles 5 and 6;

fig. 9 is a schematic flow chart of a method for automatically adjusting a rearview mirror of a semi-trailer train according to a second embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is described in further detail with reference to the accompanying drawings and the detailed description.

As shown in fig. 1, a schematic structural diagram of an automatic adjustment system for a rearview mirror of a semi-trailer train according to an embodiment of the present application mainly includes an angle variable resistance module, a deflection calculation module, and an action module.

Specifically, the angle variable resistance module is used for generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of a semi-trailer train; the deflection calculation module is used for generating a deflection action control signal according to the deflection current signal; the action module is used for controlling a rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal.

In the first embodiment, the angle variable resistance module comprises an annular base body, a resistance ring, a sliding block, a traction pin and a direct current power supply; the resistance ring is wound on the periphery of the annular base body; the annular base body is fixedly installed with the trailer through a traction pin; the sliding block is fixedly installed with the tractor and is connected with the resistance ring in a sliding manner; the direct current power supply provides a direct current signal for the resistance coil; one end of the deflection compensation device is connected with one end of the resistance coil, and the other end of the deflection compensation device and the sliding block are both connected with the deflection calculation module.

In the first embodiment, the relative deflection angle includes a left-direction relative deflection angle and a right-direction relative deflection angle; in order to accurately distinguish the normal straight running state and the turning state of the semi-trailer train, the resistance ring is further divided into a left resistance ring and a right resistance ring, and the two resistance rings are disconnected. The direct current power supply is also divided into a left power supply and a right power supply, the left voltage is only responsible for supplying power to the left resistor ring, and the right power supply is only responsible for supplying power to the right resistor ring. Specifically, one end of a left power supply is connected with the lower end of the left resistance coil, the other end of the left power supply is connected with the deflection calculation module, the left power supply, the left resistance coil, the sliding block and the deflection calculation module form a left current loop, when the semi-trailer train turns left, the tractor and the trailer produce a left-direction relative deflection angle, and the left current loop generates a left deflection current signal.

Correspondingly, one end of the right power supply is connected with the lower end of the right resistance coil, the other end of the right power supply is connected with the deflection calculation module, the right power supply, the right resistance coil, the sliding block and the deflection calculation module form a right current loop, when the semi-trailer train turns right, the tractor and the trailer produce a right relative deflection angle, and the right current loop generates a right deflection current signal.

The left deflection current signal and the right deflection current signal enter the deflection calculation module through the deflection current signal and serve as basic data of subsequent deflection angle control.

Further, in the first embodiment, a left resistor is added between the left power supply and the deflection calculation module, and a right resistor is added between the right power supply and the deflection calculation module, and the resistors are used for stabilizing the current, so that the deflection calculation module can receive a stable current signal.

In the first embodiment, a single chip microcomputer is used to implement the function of generating the deflection motion control signal of the deflection calculation module. Furthermore, in the first embodiment, a signal conditioning circuit is added to further perform left and right distinguishing and smoothing processing on the deflection current signals sent by the angle variable resistance module, so as to generate left and right deflection current signals in a digital format, and thus, the single chip microcomputer can accurately calculate the deflection action to be made by the action module according to the turning angle and the turning rate of the semi-trailer train.

In the first embodiment, the action module is composed of a stepping driving unit and a stepping motor. In order to correspond to the left and right deflection current signals, in the first embodiment, the stepping motor is divided into a left stepping motor and a right stepping motor.

The step driving control unit generates step signals according to the deflection action control signals, the step signals are also divided into left and right step signals, the left and right step motors respectively receive the respective step signals, and respectively control the left rearview mirror or the right rearview mirror to generate deflection actions with corresponding angles according to the control of the step signals.

By adopting the automatic rearview mirror adjusting system for the semi-trailer train, a deflection signal can be automatically generated according to the relative angle between the tractor and the semi-trailer, and the deflection signal is processed to obtain a rearview mirror angle adjusting signal, so that the effect of automatically adjusting the rearview mirror angle in real time in the running process of the semi-trailer train is realized.

Next, the angular deflection calculation process of the first embodiment will be described in detail in different cases.

As shown in fig. 2, for the configuration parameters of the semi-trailer train set in the embodiment,

c 'and C are left right rear-view mirror central point respectively, A is the central point (the driver eye point for short) of driver both eyes position, B' and B are the left rear end point of trailer respectively, a is the width of trailer, B is the length of pin joint to trailer afterbody, the dotted line is the visual field line that driver eye point A passes through the rear-view mirror central point reflection in the picture, it is parallel with the trailer to set for left and right side reflection visual field line, the trailer left side and the right side direct rear field of vision can be observed to the visual field line of central point, the scope that the driver can observe can be by the visual field line of central point department toward both sides diffusion, reach best visual field effect. In the first embodiment, the measurement parameters are expressed based on a vehicle coordinate system, that is, the driving direction of the vehicle is the positive direction of the X axis, the lateral vertical direction of the driving direction is the positive direction of the Y axis, and the origin is taken as the projection point O of the hinge point of the tractor and the trailer on the ground. In the first embodiment, all the set points are considered as two-dimensional points in the coordinate system XOY vertically projected on the ground plane. When the semi-trailer train does not rotate, the coordinate of the point C can be expressed as C (x)₁,y₁) The coordinates of the C 'point can be expressed as C' (x)₂,y₂)。

The first situation is as follows: when the vehicle turns right, the rotation angle of the right rear view mirror is determined

As shown in fig. 3(a), an auxiliary Δ DOC is made in the XOY plane, where CD is perpendicular to OD. Using the geometric relationship of Δ DOC, the angle β determined by the vehicle geometric parameters can be obtained:

as shown in fig. 3(b), θ' is the initial holding angle of the right rear-view mirror, and the angle Φ determined by the vehicle geometric parameters can be obtained by performing the assistance Δ AEC in the XOY plane:

as shown in FIG. 4(a), when the semi-trailer train turns to the right, the rotation angle α changes continuously, and the radius of the center point C on the right rearview mirror is L along with the tractor around the hinge point O_OCCircular motion of L_OCCan be calculated from the initial coordinates of point C, i.e.

As an auxiliary Δ OCG, CG is perpendicular to OG, the lengths of CG and OG can be obtained:

CG＝L_OCsin(α+β) (4)

OG＝L_OCcos(α+β) (5)

as shown in fig. 4(b), by making an auxiliary Δ CHB where CH is perpendicular to HB, γ:

the transformation is obtained by the formula (6):

as shown in fig. 4(a), when the semi-trailer train turns to the right, the view line of the right rearview mirror also turns clockwise around C, when turning to a certain angle, the view line will intersect with the B point at the right rear end of the trailer, at this time, if the right rearview mirror is not adjusted, the BC line will continuously shift to the left side, the view of the driver will also continuously shrink, i.e. the driver will not see the right rear end of the trailer, at this time, it is necessary that the rearview mirror can actively turn according to the change of the rotation angle between the trailer and the tractor, so that the view range can always include the B point at the right rear end of the trailer.

Considering the critical operating condition, namely the condition that the sight line just intersects with the point B at the right rear end of the trailer is the critical operating condition, as shown in FIG. 4(a)The right sight line is now parallel to the longitudinal axis of the tractor, and it is clear that the angle γ formed by BC and HB is equal to the relative angle of rotation α between trailer and tractor, which angle of rotation α is referred to as the rotation threshold α₀Can be expressed as:

namely, when the semi-trailer train turns right, if the relative included angle of the trailer relative to the tractor is larger than the rotation threshold value alpha₀And the right rearview mirror is driven by the right stepping motor to rotate so as to enlarge the visual field of the driver.

As shown in fig. 5(a), JC is an angular bisector of two lines of sight, JC is perpendicular to the mirror surface, and angle 2 is an angle Φ in fig. 3(b), and angle 1 is equal to the sum of the mirror initial angle θ 'and the mirror active rotation angle θ in fig. 3(b), i.e., < 1 ═ θ' + θ. And the angle 1+ 2+ 3 is equal to 90 degrees, then:

∠3＝90°-θ-θ′-φ (9)

as shown in fig. 5(b), L2 is parallel to the X axis, L3 is perpendicular to the right side of the tractor, and L4 is parallel to the right side of the tractor, and it can be known that ═ 8 ═ α, and from the same in-phase angle, it can be known that ═ 7 ═ 8 ═ α.

From JC, the angular bisector of the two lines of sight:

∠3＝∠4+∠5＝90°-θ-θ′-φ (10)

as can be seen from fig. 5 (a):

∠4＝∠1＝θ+θ′ (11)

from the formulas (10) and (11):

∠5＝90°-2θ-2θ′-φ (12)

combining FIGS. 5(a) and (b) can yield:

∠7＝∠5+∠6＝∠5+γ (13)

combining the above angle relationships, we can obtain:

α＝90°-2θ-2θ′-φ+γ (14)

the relation between the relative rotation angle alpha between the tractor and the trailer and the rotation angle theta of the rearview mirror can be obtained by the arrangement formula (14):

the γ angle of formula (7) may be substituted for formula (15):

the angle β and the angle φ in the formula (16) can be obtained from the formula (1) and the formula (2) based on the vehicle parameters, θ' is the initial holding angle of the right rear view mirror, L_OCCan be calculated from the initial coordinates of point C, and therefore these can be considered as given quantities. Thus, the relation between the relative rotational angle α between the tractor and the trailer and the rotational angle θ of the right mirror when the semi-trailer train turns to the right is given by equation (16).

When the semi-trailer train turns right, the relative rotation angle alpha between the trailer and the tractor is larger than the angle threshold value alpha₀And then, the action module controls the right rearview mirror to generate a corresponding rotation angle theta according to the relation of the formula (16), so that the visual field on the right side of the driver is widened.

Case two: determining the rotation angle of the left rearview mirror when the vehicle turns left

Since the present case and the case are symmetrical, and the partial position corresponds to the case one, the same character representation is used.

As shown in fig. 6(a), an assist Δ D ' OC ' is made in the XOY plane, where C ' D ' is perpendicular to OD '. Using the geometric relationship of Δ D 'OC', the angle δ determined by the vehicle geometric parameters can be found:

as shown in fig. 6(b), η ' is the initial holding angle of the left-hand mirror, and as an auxiliary Δ AE ' C ' in the XOY plane, the angle ∈ determined by the vehicle geometry can be obtained:

as shown in FIG. 7(a), when the semi-trailer train turns to the left, the rotation angle λ is constantly changed, and the radius of the center point C' on the left rearview mirror is L along with the tractor around the hinge point O_OCCircular motion of L_OC'Can be calculated from the initial coordinates of point C', i.e.

When the auxiliary delta OC ' K is made, the C ' K is perpendicular to the OK, the lengths of the C ' K and the OK can be obtained:

C′K＝L_OC′sin(δ+λ) (20)

OK＝L_OC′cos(δ+λ) (21)

as shown in fig. 7(B), making an auxiliary Δ C 'B' L, where C 'L is perpendicular to B' L, yields μ:

the following equations (22) can be transformed:

as shown in fig. 7(a), when the semi-trailer train turns to the left, the view line of the left rear-view mirror also turns counterclockwise around C ', when turning to a certain angle, the view line will intersect with the point B ' at the left rear end of the trailer, at this time, if the left rear-view mirror is not adjusted, the line B ' C ' will continuously shift to the right, the view of the driver will also continuously shrink, i.e., the driver will not see the left rear end of the trailer, at this time, it is necessary that the rear-view mirror can actively turn according to the change of the rotation angle between the trailer and the tractor, so that the view range can always include the point B ' at the left rear end of the trailer.

Considering the critical operating condition, i.e. the condition that the sight line just intersects the point B 'at the left rear end of the trailer, as shown in fig. 7(a), when the sight line at the left side is parallel to the longitudinal axis of the tractor, it is obvious that the angle formed by B' C 'and B' L is equal to the relative rotation angle λ between the trailer and the tractor, and the rotation angle λ is called the rotation threshold λ₀Can be expressed as:

namely, when the semi-trailer train turns left, if the relative included angle of the trailer relative to the tractor is larger than the rotation threshold lambda₀The left rearview mirror is driven by the left stepping motor to rotate so as to enlarge the visual field of the driver.

As shown in fig. 8(a), MC 'is an angular bisector of two visual field lines, MC' is perpendicular to the mirror surface, angle 2 is an angle ∈ in fig. 6(b), and angle 1 is equal to the sum of the original mirror angle η 'and the active mirror rotation angle η in fig. 6(b), that is, angle 1 ═ η' + η. And the angle 1+ 2+ 3 is equal to 90 °, namely:

∠3＝90°-η-η′-ε (25)

as shown in fig. 8(b), L2 is parallel to the X axis, L3 is perpendicular to the left side of the tractor, and L4 is parallel to the left side of the tractor, and it can be known that ═ 8 ═ λ, and from the same in-phase angle, it can be known that ═ 7 ═ 8 ═ λ.

The angular bisector of the two lines of sight is known from MC':

∠3＝∠4+∠5＝90°-η-η′-ε (26)

as can be seen from fig. 8 (a):

∠4＝∠1＝η+η′ (27)

from the equations (26) and (27):

∠5＝90°-2η-2η′-ε (28)

combining FIGS. 8(a) and (b) can yield:

∠7＝∠5+∠6＝∠5+μ (29)

combining the above angle relationships, we can obtain:

λ＝90°-2η-2η′-ε+μ (30)

the relation between the relative rotation angle lambda between the tractor and the trailer and the rearview mirror rotation angle eta can be obtained by the arrangement formula (30):

substituting the μ angle of equation (23) into equation (31) can yield:

the angle δ and the angle ∈ in the formula (32) can be obtained from the formula (17) and the formula (18) based on the vehicle parameters, η' is the initial holding angle of the left-hand mirror, and L_OC'Can be calculated from the initial coordinates of point C' and therefore these can be considered as given quantities. Thus, equation (32) gives the relationship between the relative rotation angle λ between the tractor and the trailer and the left mirror rotation angle η when the semi-trailer train turns left.

When the semi-trailer train turns left, the relative rotation angle lambda between the trailer and the tractor is larger than the angle threshold lambda₀And then the action module controls the right rear view mirror to generate a corresponding turning angle eta according to the relation of the formula (32), thereby widening the visual field of the left side of the driver.

Example two

As shown in fig. 9, a method for automatically adjusting a rearview mirror of a semitrailer in accordance with a second embodiment of the present application includes the following steps:

s1, generating a deflection current signal according to the relative deflection angle of a tractor and a trailer of a semi-trailer train;

in the second embodiment, the relative deflection angle includes a left-direction relative deflection angle and a right-direction relative deflection angle; correspondingly, the deflection current signals comprise a left deflection current signal and a right deflection current signal;

when the tractor and the trailer generate a left-direction relative deflection angle, a left deflection current signal is generated;

when the tractor and the trailer generate a right-direction relative deflection angle, a right deflection current signal is generated.

S2, generating a deflection action control signal according to the deflection current signal, wherein the signal comprises a deflection angle and a deflection rate;

s3, controlling a rearview mirror of the semi-trailer train to generate deflection action according to the deflection action control signal;

in the second embodiment, the yaw action is divided into a left rearview mirror yaw action and a right rearview mirror yaw action; specifically, when a left deflection current signal is generated, the rearview mirror of the semi-trailer train generates a left rearview mirror deflection action; when the right deflection current signal is generated, the rearview mirror of the semi-trailer train generates right rearview mirror deflection action.

According to the automatic adjusting method for the rearview mirror of the semi-trailer train, the deflection signal can be automatically generated according to the relative angle between the tractor and the semi-trailer, the deflection signal is processed to obtain the deflection action control signal for adjusting the angle of the rearview mirror, and the deflection angle of the rearview mirror is adjusted according to the deflection signal, so that the effect of automatically and real-timely adjusting the angle of the rearview mirror in the running process of the semi-trailer train is realized.

The above-described embodiments are merely illustrative of the preferred embodiments of the present application, and do not limit the scope of the present application, and various modifications and improvements made to the technical solutions of the present application by those skilled in the art without departing from the spirit of the present application should fall within the protection scope defined by the claims of the present application.