WO2021008241A1

WO2021008241A1 - Vehicle steering method and system, steering method for traveling mechanism, and traveling mechanism

Info

Publication number: WO2021008241A1
Application number: PCT/CN2020/092623
Authority: WO
Inventors: 江峰; 徐振立; 于广浩; 于彬; 陈炳辉; 曾欣; 戴超
Original assignee: 上海燧方智能科技有限公司
Priority date: 2019-07-18
Filing date: 2020-05-27
Publication date: 2021-01-21
Also published as: CN112238896B; CN112238896A

Abstract

A vehicle steering method and system, and a steering method for a traveling mechanism, said method comprising: a distributed driving power source directly or indirectly and independently applying a torque required for steering to a steering wheel, so that a driving force is generated between the steering wheel and a contact surface, the driving force causing a rotational torque T _rotate to a steering shaft of the steering wheel, and overcoming a relevant drag torque, such as a frictional drag torque when the steering wheel rotates about the steering shaft and between the steering wheel and the contact surface, and causing the steering wheel to rotate about the wheel steering shaft. In addition, a yaw torque T _yaw about the steering shaft of the steering wheel is set, this torque produces a corresponding torque that causes the wheel to reach a steady state when the wheel yaws to a desired position, so as to form steady steering. The steering wheel in the present application directly receives a torque that is generated by a driving power source and required for steering, so that a driving force (forward or backward) is generated between the steering wheel and the contact surface, and the driving force serves as a power source for steering, thereby achieving the effect of steering; and the steering wheel has a simple structure and occupies a small space.

Description

Vehicle steering method, system, steering method of driving mechanism and driving mechanism

Technical field

The invention relates to the principle of vehicle steering, in particular, to a vehicle steering method, a vehicle steering system, and a traveling mechanism including the vehicle steering system.

Background technique

At present, there are three main types of common vehicle steering systems: the first type is the traditional vehicle steering system, which consists of three parts: steering control mechanism, steering gear and steering transmission mechanism. Generally, a hydraulic or electric power steering or power system is also required to achieve steering assistance or automatic control. Please refer to Figure 1. When the car is turning, the driver applies a steering torque to the steering control mechanism, which is transmitted to the steering transmission mechanism through the steering gear to control the steering wheel deflection. The second type is differential steering, where the wheels cannot be deflected, and the vehicle realizes steering by separately controlling the rotation speed of the left and right driving wheels. Commonly used on tracked vehicles or other wheeled special vehicles. The third type is the steering system of the steering gear. Each wheel is equipped with an independent steering gear. The steering gear can control the deflection of the wheel to realize the independent deflection angle of each wheel. There are some other very common steering systems, such as the Mecanum wheel steering system.

The current steering mode has the following defects:

First, the first type of driving mechanism steering method has the following defects.

First of all, traditional driving mechanisms (for example, automobiles) require a set of independent and complex steering systems, including steering control mechanisms, steering gears, and steering transmission mechanisms, because they need to decouple the two motions of driving and steering. A hydraulic or electric power steering or power system is required to achieve steering assistance or automatic control. In particular, the existing steering system includes a complicated steering transmission mechanism, which not only requires high precision, but also has an extremely complex structure. As a result, the entire research and development is difficult and costly. In addition, due to the complicated structure of the independent steering system, which occupies a large internal space of the vehicle, it is generally installed under the vehicle body, which limits the height of the vehicle from the ground, and also affects the application in some special vehicle body design or applications. For example, a driving mechanism designed for the elderly or the disabled has a complicated structure and takes up a large space due to the vehicle steering system installed under the vehicle body, and its height cannot be made small, which greatly affects the comfort of the elderly or the disabled.

Secondly, as the space requirements of automobile design increase, distributed drives have been used in vehicle design to improve space efficiency, such as four-wheeled automobiles with in-wheel motors. However, the steering system of this type of vehicle is still a traditional steering system, and a steering torque needs to be applied through the steering control mechanism and transmitted to the steering transmission mechanism through the steering gear to control the steering wheel deflection. The power source for steering is still a human driver or a dedicated steering motor.

The second type of driving mechanism steering method has the following defects: the differential steering system makes the car body steer by controlling the rotation speed of the wheels on both sides, which causes the wheels to produce larger lateral slip, the tires are worn seriously, and the resistance is large. Higher requirements for power systems and vehicles.

The third type of driving mechanism steering method has the following defects: the steering gear steering system is equipped with a dedicated steering steering gear for each wheel, resulting in a complicated system, a large space occupation, and a high cost.

Summary of the invention

Aiming at the defects in the prior art, the first object of the present invention is to provide a vehicle steering method and vehicle steering system.

In view of the defects in the prior art, the second object of the present invention is to provide a steering method of a traveling mechanism and a traveling mechanism.

A vehicle steering method for distributed driving control of the wheels, including: the steering wheel is directly or indirectly applied to the steering wheel by the distributed driving power source directly or indirectly, and the driving force in the opposite direction is generated between the steering wheel and the contact surface, The driving force generates a rotational torque T _{spin on the} steering shaft of the steering wheel, and after overcoming the frictional resistance torque of the steering wheel around the steering shaft, such as the frictional resistance torque of the steering wheel around the steering shaft and the contact surface of the steering wheel and the steering wheel, it causes the The steering wheel rotates around the steering shaft of the wheel. In addition, the overall dynamic balance of the vehicle can be calculated, including at least one of the driving force, resistance, and centrifugal force, so that the vehicle can achieve a desired state of motion.

The method also includes: setting a yaw moment T _bias around the steering shaft of the steering wheel, which generates a corresponding moment that makes the wheel reach a stable state when the wheel _deviates to a desired position, so as to form a stable steering.

When the wheel is in a yaw state, the yaw moment can change correspondingly with the change of the wheel yaw angle, and the direction of the rotation moment is always opposite when the wheel is yaw. or

Before the wheel is deflected to the desired position, the yaw moment is any torque value that allows the wheel to deflect; when the wheel is turned to the desired position, the yaw moment will be set to the torque that can maintain the wheel at this position.

Choose at least one point B as the force application point B that generates the deflection moment, set the joints OA and AB as rigid bodies, point O as the geometric center of the wheel, point A as the turning point when point O rotates around the steering axis of the wheel, and point B as the generating point At the force application point of the deflection moment, a deflection control element that can produce deformation is arranged between at least one connection point B and the vehicle body. When the wheel is pointing straight ahead, the deflection control element is in a free state and does not generate tension or pressure. when the deflection force is applied to the wheel, the deflection control element is _pulled or stretched a tensile force F / F, and a pressure is compressed _pressure, controlling the steering wheel about the steering wheel shaft.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention utilizes the characteristic that the torque of each wheel of a distributed drive vehicle can be independently controlled. Instead of using a dedicated steering motor or a human driver as the power source for steering, it uses the forward or backward driving force of each wheel as the steering force. The power source can realize vehicle steering in a low-cost, simple, robust and sensitive way; controlling the magnitude of the force can be used to generate driving force between the steering wheel and the contact surface, without complicated steering gear and steering transmission mechanism, The structure is simple and does not take up a lot of space.

2. By controlling the different driving forces of each wheel, the present invention can individually control the deflection angle of each steering wheel to better meet the overall steering demand of the vehicle;

3. The steering wheels of the present invention do not need to be physically connected, which is conducive to the modular layout of the vehicle, which will greatly improve the space utilization efficiency of the vehicle, shorten the development cycle, and save the development cost.

Description of the drawings

By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present invention will become more apparent:

Figure 1 is a schematic diagram of vehicle steering based on Ackerman's theory;

Figure 2 is a left view of the force analysis of a single wheel in the present invention;

Figure 3 is a top view of the force analysis of a single wheel in the present invention;

Figure 4 is a top view of the elastic element in the present invention being stressed;

Figure 5 is a top view of the elastic element in the present invention in another direction where the force is applied;

6A-6D are schematic diagrams of the whole vehicle steering in the present invention;

Figure 7 is a schematic diagram of the structure of the steering wheel in the present invention;

Figure 8 is a schematic diagram of the entire vehicle structure of the steering system in the present invention;

Figure 9 is a schematic diagram of an elastic element in a modification of the present invention;

Figure 10 is a flowchart of the vehicle steering method in the present invention;

Fig. 11 is an example diagram of using an active air spring to make a deflection control element.

In the figure: 1 is the axle pin; 2 is the upper control arm; 3 is the first ball joint; 4 is the steering knuckle; 5 is the frame assembly; 6 is the fourth ball joint; 7 is the lower control arm; 8 is the deflection control Elements; 9 is the third ball head; 10 is the second ball head; 11 is the tire; 12 is the hub motor; 13 is the deflection control element of the left steering wheel, 14 is the deflection control element of the right steering wheel, and 15 is the left steering wheel 16 is the right steering wheel; 17 is the left rear wheel body; 18 is the right rear wheel body; 19 is the electronic control unit; 20 is the lever; 21 is the rear upper control arm; 22 is the rear lower control arm; 23 is the first elastic 24 is the second elastic member 25 is an air compressor; 26 is a deflection control element; 27 is an air chamber.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be pointed out that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

First of all, it needs to be explained that the traveling mechanism includes various devices that can cause the object to move or displace, including but not limited to various wheeled or crawler-type mechanisms. The steering mechanism includes the control of various wheeled or crawler-type vehicles. Direction to realize the mechanism that the driving direction is different from the original existing direction.

In this embodiment, the present invention is also based on Ackerman's theory. According to the Ackerman steering geometry design, when turning along a curve, the centers of the four wheel paths roughly meet on the extension line of the rear axle, so that the vehicle can turn smoothly, as shown in Figure 1.

For vehicles, to achieve wheel deflection, a moment around the steering axis of the wheel must be applied, that is, around the kingpin of the wheel. The traditional automobile steering system applies steering force to the wheel knuckles through the steering transmission mechanism, thereby generating torque that deflects the wheels. The present invention combines the characteristics of distributed driving that each wheel can independently control the driving torque, and proposes a new steering torque source and steering mode. The driving force of the steering wheel drives the wheels to deflect.

The following first takes a single wheel as an example to illustrate. During the process, the vehicle dynamics factors are simplified. For example, the lateral force of the tire, the kingpin inclination angle, and the tire deformation are not considered. The actual development and application can be based on The simplified model adds a balanced design that considers various related parameters. The specific description is as follows: when the distributed power source applies a counterclockwise torque T _drive to the wheels (as shown in the left view of Fig. 2), the contact surface will give the wheels a driving force F to the left. In the top view on the right, the wheel deflects around the vertical wheel steering shaft (king pin) at point A. The driving force F from the ground to the tire will produce a rotational torque T _{spin on the} steering shaft (king pin) of the wheel. When this torque is sufficient to overcome the resistance torque T _{resistance of the} system around the steering shaft (king pin) of the wheel, the wheel will turn around the wheel The shaft (king pin) rotates. By controlling the magnitude of the driving torque T _drive , the magnitude of the driving force F can be controlled, thereby indirectly controlling the magnitude of the steering torque T _spin . When T _{spin is} greater than T _resistance , if the system has no other torque around the wheel steering axis (kingpin), the wheel will continue to deflect until the limit of the mechanical position. In order to stably control the degree of wheel deflection, it is necessary to introduce a new torque T _deviation around the steering axis (king pin) of the wheel. This torque needs to generate a suitable torque when the wheel deflects to the desired position, so that the wheel can reach a stable state. , So as to maintain the angle, forming a stable steering.

The vehicle steering vehicle mentioned later can be a device that contains 4 or more wheels to match the torque to achieve the desired driving, including unmanned vehicles, manned vehicles and other tools with driving functions, or simulation or Toys, models, etc. with similar functions. Of course, this example can also be applied to a device or system that has a movable wheel type or partial wheel type to complete the mobile function.

The driving power source mentioned in the present invention includes a power source (such as a drive motor) that provides a torque consistent with the rotation direction of the wheel, and also includes a power source (such as a brake system) that provides a torque that is opposite to the rotation direction of the wheel.

A vehicle steering method for distributed driving control of the wheels, including: the steering wheel is directly or indirectly applied to the steering wheel by the distributed driving power source to generate the driving force between the steering wheel and the contact surface. The driving force generates a rotational torque T _{spin on the} steering shaft of the steering wheel, and overcomes the frictional resistance torque of the steering wheel around the steering shaft, such as the frictional resistance torque of the steering wheel around the steering shaft and the contact surface between the steering wheel and the steering wheel, causing the steering The wheel rotates around the steering shaft of the wheel. A deflection moment T _bias around the steering axis of the steering wheel is set. This moment generates a corresponding torque that makes the wheel reach a stable state when the wheel _deviates to a desired position to form a stable steering.

When the torque required for the steering wheel is opposite to the direction of rotation of the wheel, it can also be provided by the braking system.

The way to realize this moment can be divided into active and passive. Passively controlled T- _deflection refers to the torque with the following characteristics: when the wheel is not deflected, the magnitude is 0, and it can change accordingly with the change of the wheel deflection angle; when the wheel is in the deflection state, the deflection torque can follow the wheel deflection angle The size changes accordingly, and the direction of the rotational torque is always opposite when the wheel is deflected. Generally speaking, this moment will cause the wheel to have a tendency to return to the positive direction, that is, this moment will always be opposite to the direction of T _spin when the wheel is deflected. Active control means _biasing torque T with the following characteristics: the former is not deflected to a desired position, the deflecting torque, T is an arbitrary _partial deflection of the wheel allow the wheel torque value; when the wheel to the desired position, the _bias provided yawing moment T Determined to maintain the torque of the wheel at this position.

In the present invention, there is no independent steering mechanism of a traditional vehicle. The steering wheel directly receives the torque required for steering generated by the driving power source, and the forward or backward driving force of each wheel is used as the power source for steering, so that the steering wheel and the contact surface are generated The driving force thus achieves the effect of steering, there is no complicated steering gear and steering transmission mechanism, the structure is simple and does not take up a lot of space. The invention realizes vehicle steering in a low-cost, simple, robust and sensitive way; in particular, through the control of the different driving forces of each wheel, the deflection angle of each steering wheel can be individually controlled to better meet the overall requirements of the vehicle. Turn to demand.

Example one

The following is an example of an implementation of passive control of T _bias :

Choose at least one point B as the force application point B that generates the deflection moment, set the joints OA and AB as rigid bodies, point O as the geometric center of the wheel, point A as the turning point when point O rotates around the steering axis of the wheel, and point B as the generating point The force application point of the deflection moment,

At least one deformable deflection control element is arranged between at least one connection point B and the vehicle body. When the wheel is pointing straight ahead, the deflection control element is in a free state, and no tension or pressure is generated. When the force is applied, the wheel deflects. When the deflection control element is stretched to generate a tensile force F _pull or/and compressed to generate a pressure F _pressure , the steering wheel is controlled to rotate around the steering shaft of the wheel. There can be multiple connection points B, and there can also be multiple deflection control elements that can produce deformation. That is, the deflection control element is stretched to generate a tensile force F _pull controls the steering wheel to rotate around the wheel steering axis, or the deflection control element is compressed to generate pressure F _pressure controls the steering wheel to rotate around the wheel steering axis, or it can be stretched to generate a tensile force F _pulls at the same time applying a compressive force and F _pressure controls the steering wheel to rotate around the wheel steering shaft.

In this example, first take a connection point B and a deflection control element as an example.

At least one point B is introduced as the point of action for generating the T- _bias force. OAB is a rigid body that can only rotate around the wheel steering shaft (king pin) at point A. Design at least one deflection control element that can produce deformation between point B and point C on the body: when the wheel is pointing straight ahead, the deflection control element is in a free state, and no tension or pressure is generated.

When the wheel deflection to the right (FIG. 4), the deflection control element is stretched, _pulling a tensile force F, which is generated when a wheel around a steering shaft (kingpin) of the torque and _{a spin} torque T, _resistive drag torque T when the balance wheel deflection angle can be maintained stable; if you cancel or reduce the drive torque T _drive, _{a spin} F and T will disappear or decrease, the moment around the kingpin will no longer form the balance wheel in the _pull tensile force F Driven by the next return to normal. When the wheel deflection to the left (FIG. 5), the deflection control members to be compressed, _{the pressure} generated force F, which is generated when the steering wheel about the axis (kingpin) of the torque and _{a spin} torque, T, T drag torque _resistance balance When the wheel can maintain a stable deflection angle; when the driving torque T _{drive is} canceled or reduced, the driving force F and T _spin will disappear or decrease, and the wheel will return to normal under the F _pressure .

The torque balance equation when the wheel deflection is stable is: T _spin = T _resistance + T _deviation

When the wheel turns to the right, the following formula holds: F×OA=T _resistance +F _pull ×L ₁ ; When the wheel turns to the left, the following formula holds: F×OA=T _resistance +F _pressure ×L ₂ .

There can be multiple connection points. For example, take Figure 9 as an example. The connection points B are points B1 and B2 respectively. Points B1 and B2 are connected to point A respectively. The connection points OA, AB1 and AB2 are set as rigid bodies. Deflection control elements are set on the points to achieve deformation. When the wheel is pointing straight ahead, multiple deflection control elements are in a free state, and no pulling force or pressure is generated. When the wheel is deflected by applying force, multiple deflection the control member is stretched and a tensile force F _{to pull} / _pressure or compression force F is generated, controls the steering wheel about the steering wheel shaft, such a process scheme may provide another implementation possible. And the stability is relatively strong.

Example two

The following takes an implementation of active control of T _bias as an example to introduce:

Active control T _deviation can be achieved by actively changing the state of the deflection control element in response to the steering demand, such as changing the stiffness of the deflection control element through an electronic control device, or changing the length of the deflection control element through an electronic control structure to indirectly generate the torque T _deviation . So that the wheels are maintained at a stable deflection angle. When the wheel needs to return to the center, the active deflection control element can provide the centering torque, or it can automatically return to the center by adjusting the size and direction of the driving torque of the steering wheel. (Figure 11 is an example). One of the embodiments is to use an active air spring to make the deflection control element. The air compressor 25 can inflate or pump air into the air chamber 27, and the air chamber 27 will cause the overall stiffness of the deflection control element 26 due to the increase or decrease of the internal gas. Raise or lower to achieve rigidity control of the deflection control element. The stiffness change of the deflection control element will affect the steering response characteristics: when the stiffness of the deflection control element becomes smaller, the same driving torque can make the steering wheel deflect faster and achieve a larger deflection angle; otherwise, the deflection of the steering wheel will It will slow down and the deflection angle will be smaller.

In actual situations, some complex impact conditions need to be considered. For example, the wheel still has a certain resistance f when there is no driving torque, and it is only used as a driven wheel to roll forward. At this time, a small amount of compression of the deflection control element is still required to balance the rotational torque generated by this resistance. For this reason, the resistance f when the wheels are pointing straight ahead can be tested through the actual vehicle, and the pressure generated by the small compression amount of the pre-designed deflection control element can be used to balance the resistance f when the wheels are running to ensure that the wheels go straight during driving. Similar to the above-mentioned influencing conditions, it does not conflict with the main principle and method of the present invention, and can be specifically considered and resolved in actual application development.

A vehicle steering system that individually controls the deflection angle of the steering wheel by separately driving and controlling each wheel that needs to be steered controlled, including:

Distributed driving power source: used to provide steering force for the steering wheels. The driving power source mentioned in the present invention includes a power source (such as a drive motor) that provides a torque consistent with the direction of rotation of the wheel, and also includes a power source that provides the direction of rotation of the wheel. Power source with opposite torque (such as braking system);

At least one steering wheel: used to receive the direct or indirect force of the distributed driving power source and generate driving force between the steering wheel and the contact surface;

Control center: used to calculate the direct or indirect force of the distributed driving power source, and calculate the rotational torque T _spin generated by the driving force on the steering shaft of the steering wheel to overcome the relevant resistance torque, so that the steering wheel turns around the wheel steering shaft Rotate. The control center specifically refers to the vehicle electronic control unit (ECU) in the subsequent application examples.

The vehicle steering system also includes a yaw control element to generate a yaw moment T _yaw around the steering axis of the steering wheel. This moment generates a corresponding moment that makes the wheel reach a stable state when the wheel is deflected to the desired position to form a stable steering .

The deflection moment generating device further includes:

At least one deformable deflection control element is provided between the connection point B and the vehicle body. When the wheel is pointing straight ahead, the deflection control element is in a free state, and does not generate tension or pressure. When the wheel is deflected by applying force, deflection control element is stretched or compressed to produce _tensile force F _pressing force F is generated, the control steering wheel about the steering wheel shaft.

Using the steering method of the present invention, the deflection angle of each steering wheel can be individually controlled, and there is no need to establish a physical connection between the two steering wheels. For the overall steering movement of the vehicle, through the control of the different driving forces of each wheel, the overall steering, speed, and acceleration requirements of the vehicle are met. Therefore, this method can realize independent control of the deflection angle of each steering wheel according to the needs of the steering intention of the whole vehicle on various vehicles such as front-wheel steering, rear-wheel steering, and multi-axle, so as to achieve the least resistance or other required steering trajectories. .

In summary, the steering method of the traveling mechanism of the present invention includes:

The deflection angle of each steering wheel can be controlled separately, and there is no need to establish a physical connection between the two steering wheels,

For the overall steering movement of the vehicle, through the control of the different driving forces of each steering wheel, the steering center of the vehicle is on the extension line of the rear axle of the vehicle to achieve Ackerman steering.

Each steering wheel controls the steering in the following way: the steering wheel is directly or indirectly applied to the steering wheel by the distributed driving power source, so that a driving force is generated between the steering wheel and the contact surface, and the driving force is applied to the steering shaft of the steering wheel. The rotation torque T _{spin is} generated, and the related resistance torque is overcome, such as the steering wheel around the steering shaft and the friction resistance torque between the steering wheel and the contact surface, etc., causing the steering wheel to rotate around the wheel steering shaft.

In this example, the control center can calculate the overall dynamic balance of the vehicle, including at least one of the driving force, resistance, and centrifugal force, so that the vehicle reaches the desired state of motion. When the active deflection control element is used, according to the input of the deflection angle and the vehicle motion state, the characteristic targets including the stiffness and the length required for the deflection torque generator are obtained.

The following uses a four-wheel, front-axle steering vehicle as an example to describe the application of the steering method of the present invention to the entire vehicle. For this type of vehicle, in order to minimize the resistance during the entire steering process and the steering movement is as smooth as possible, the steering centers of the wheels need to coincide at one point. Since the two wheels of the rear axle cannot deflect, the steering centers of the two rear wheels are on the extension line of the rear axle, and the steering centers of the two front wheels intersect at the same point on the extension line of the rear axle (as shown in Figure 1). At this time, the deflection angles of the left and right steering wheels are not consistent (the deflection angle of the inner wheel is greater than the deflection angle of the outer wheel), and the force and direction of the deflection control element are also not consistent. The driving force required to achieve this two-wheel deflection And the direction is also different: the inner steering wheel needs the ground to give the tire the driving force to the rear of the vehicle to achieve; for the outer steering wheel, it needs to apply forward driving force. Under normal circumstances, the combined force of the two steering wheels cannot balance with the resistance in the direction of the vehicle or provide the acceleration required by the vehicle. In order to balance the resultant force of the four-wheel drive with the forward resistance of the vehicle or provide the acceleration required by the vehicle, it is necessary to apply driving torque or braking torque in different directions on the two wheels of the rear axle to match, so as to achieve the desired movement of the vehicle Stable way forward. According to vehicle dynamics, comprehensive consideration of driving force, resistance, lateral force, gravity and road factors, etc., through the vehicle's longitudinal and lateral force balance, the drive force distribution of each wheel can be obtained. Figures 6A-6D below list four working conditions on flat roads. Fig. 6A illustrates the situation of forward turning left. In the figure, F1, F2, F3, and F4 respectively represent the driving force or backward drag force of the ground to each wheel. Fig. 6B shows a case of turning left and reversing. Fig. 6C is the working condition of forward turning right, and Fig. 6D is the working condition of reverse turning right.

Application example

Based on the foregoing original theory, in an embodiment of the present invention, the steering wheel provided by the present invention includes a tire body, a steering knuckle 4, an upper control arm 2, a lower control arm 7, and a yaw control element 8 (as shown in Figure 8); In this example, the tire body may include an in-wheel motor and a tire. The tire here mainly refers to a rubber part.

One side of the tire body is provided with a steering knuckle 4, the upper end of the steering knuckle 4 is connected to one end of the upper control arm 2, and the lower end of the steering knuckle 4 is connected to one end of the lower control arm 7;

One end of the deflection control element 8 is connected to the steering knuckle 4; the other end of the upper control arm 2, the other end of the lower control arm 7, and the other end of the deflection control element 8 are used to connect the vehicle Frame assembly 5.

In this embodiment, by applying the deflection control element in the present invention, the driving force of the wheels can be used to promote the steering of the vehicle, which can make the steering of the vehicle more convenient and faster and save costs.

In an embodiment of the present invention, the steering wheel provided by the present invention further includes a first ball head 3 and a second ball head 10;

The upper end of the steering knuckle 4 is connected to the upper control arm 2 through the first ball head 3; the lower end of the steering knuckle 4 is connected to the lower control arm 7 through the second ball head 10.

The present invention also includes a third ball head 9 and a fourth ball head 6;

One end of the deflection control element 8 is connected to the side end of the steering knuckle 4 through the third ball head 9, and the other end is used to connect to the frame assembly 5 through the fourth ball head 6.

The tire body includes an in-wheel motor 12 and a tire 11; the in-wheel motor 12 is arranged in the inner cavity of the tire 11;

The in-wheel motor 12 is connected to the steering knuckle 4 through a connecting shaft.

The line connecting the centers of the first ball head 3 and the second ball head 10 is the main axis of the deflection of the tire body, ie.

In an embodiment of the present invention, point B is introduced as the point of action for generating the T- _bias force, and OAB is a rigid body that can only rotate around the wheel steering axis at point A, that is, the kingpin. The deflection control element 8 is designed between point B and point C on the vehicle body;

When the tire body points straight forward and the torque of the in-wheel motor 12 is less than the preset torque threshold, the deflection control element 8 is in a free state; no tension or pressure is generated. This torque threshold will be affected by factors such as tire size, vehicle weight, and steering knuckle size.

When the tire body deflects to the right, as shown in FIG. 4, when the in-wheel motor 12 drives the tire body to deflect inward, the deflection control element 8 is in a stretched state, and a pulling force F is generated. around the wheel steering shaft torque and a spin torque, T, T drag torque _resistance can be maintained stable equilibrium tilt angle of the wheel; if you cancel or reduce the drive torque T _drive, F and T spin will disappear or decrease, the wheel in the positive drive force F _{to pull} the next time.

When the left tire deflection body 5, when the tire body 12 of the drive wheel motor deflected outwardly, the deflection control member 8 in a compressed state; _pressure generated force F, which is generated when The wheel can maintain a stable deflection angle when the torque around the steering axis of the wheel is balanced with the torque T _rotation and the resistance torque T _resistance ; when the driving torque T _{drive is} canceled or reduced, F and T _rotation will disappear or decrease, and the wheel will be at F _{The pressure} drives the next back to normal.

In a modified example, as shown in FIG. 9, the deflection control element 8 includes a first elastic member and a second elastic member;

One end of the first elastic member and the second elastic member is connected to the steering knuckle 4; one end of the first elastic member and the second elastic member is used to connect to the frame assembly 5;

The first elastic member and the second elastic member are arranged on both sides of the steering knuckle 4 and are symmetrically distributed around the steering knuckle 4. When the first elastic member and the second elastic member are compressed, pressure is generated, and when the first elastic member and the second elastic member are stretched, no tensile force is generated. The function of a single deflection control element 8 can also be realized by the cooperation of the first elastic member and the second elastic member.

When the steering wheel provided by the present invention is used, the deflection angle of each steering wheel can be individually controlled, and there is no need to establish a physical connection between the two steering wheels. For the overall steering movement of the vehicle, by applying different driving forces to each steering wheel, the requirements of the overall steering, speed and acceleration of the vehicle are met. Therefore, the present invention can realize independent control of the deflection angle of each steering wheel according to the needs of the steering intention of the whole vehicle on various vehicles such as front-wheel steering, rear-wheel steering, and multi-axle, so as to achieve minimum resistance or other requirements. Turn to track.

In the embodiment of the present invention, the vehicle provided in the present invention includes the steering wheel in the above embodiment, and also includes a rear wheel body, a tie rod 20, a rear upper control arm 21, a rear lower control arm 22, and a frame assembly 5;

The steering wheel is arranged at the front end of the frame assembly 5, and the steering wheel is connected to the frame assembly 5 through the deflection control element 8, the upper control arm 2, and the lower control arm 7;

The rear wheel body is arranged at the rear end of the frame assembly 5, and the rear wheel body is connected to the frame assembly 5 through a tie rod 20, a rear upper control arm 21, and a rear lower control arm 22.

The upper control arm 2 and the lower control arm 7 of the steering wheel are connected to the frame assembly 5 through the axle pin 1.

The application of the steering wheel of the present invention to the entire vehicle is further described. For this type of vehicle, in order to minimize the resistance during the entire steering process and the steering movement is as smooth as possible, the steering centers of the wheels need to coincide at one point. Since the two wheels of the rear axle cannot be deflected, the steering centers of the two rear wheels are on the extension line of the rear axle, and the steering centers of the left steering wheels of the two front wheels intersect at the same point on the extension line of the rear axle, as shown in Figure 6. . At this time, the deflection angles of the left and right steering wheels are inconsistent, that is, the deflection angle of the left steering wheel is greater than the deflection angle of the right steering wheel, and the force and direction of the deflection control element 8 are also inconsistent. In order to realize the two steering The magnitude and direction of the driving force required for wheel deflection are also different: the left steering wheel requires the ground to give the tires to the rear of the vehicle to achieve the driving force; for the right steering wheel, forward driving force is required. Under normal circumstances, the combined force of the two steering wheels cannot balance with the resistance in the direction of the vehicle or provide the acceleration required by the vehicle. In order to balance the resultant force of the four-wheel drive with the forward resistance of the vehicle or provide the acceleration required by the vehicle, it is necessary to apply driving torque or braking torque in different directions on the two wheels of the rear axle to match, so as to achieve the desired movement of the vehicle Stable way forward. Figure 6 illustrates one of these situations. In the figure, F1, F2, F3, and F4 respectively represent the driving force or backward drag force of the ground to each wheel.

The right front suspension and the left front suspension are completely symmetrical in design, so they also have a steering function. The suspension of the two rear wheels in this embodiment also adopts a double-wishbone independent suspension. The difference from the front suspension is that the deflection control element 8 is replaced by the tie rod 20 with an invariable length. In this way, when a forward or reverse driving torque is applied to the rear wheels, since the length of the tie rod 20 is immutable, the rear wheels cannot rotate around their kingpins, so that they can only roll forward or rearward of the vehicle. The purpose of the front wheel steering.

In the embodiment of the present invention, the vehicle steering method provided by the present invention is used to control the steering of the steering wheel. The steering wheel includes at least a tire body and a deflection control element. The tire body is connected to the frame assembly through the deflection control element 8. 5. Including the following steps (Figure 10 is only an implementation flow chart):

Step S1: Obtain a steering instruction;

Step S2: Calculate the yaw angle of each steering wheel according to the steering command, and then calculate a steering torque of each wheel and issue a corresponding control command. The steering wheel deflects under this torque, and the vehicle turns;

Step S3: Obtain the steering end command, recalculate the torque required by each wheel when going straight, and issue a control command to keep the wheel deflection torque no longer present, the wheels return to the center, and the vehicle goes straight.

Specifically, in this embodiment, when the vehicle is started, the electronic control unit (ECU) first confirms whether it has received a steering request and a vehicle speed request from a human driver or an unmanned driving system. If a steering-related instruction is received, the ECU will first Calculate the required deflection angle of the left steering wheel 15 and the right steering wheel 16;

In this embodiment, the secondary steered wheels are the left rear wheel 17 and the right rear wheel 18, and may also be other non-steered wheels in the modified example.

Then ECU calculates the torque of each wheel according to the dynamic balance of the whole vehicle; and then controls the motor of each wheel according to the calculation result.

With this torque distribution, the vehicle can achieve stable steering.

When an updated steering command is sent, the ECU will recalculate the torque distribution based on the steering command and the vehicle speed command, and the vehicle will start a new steering condition. Until the ECU receives the instruction of the vehicle to go straight, the ECU will redistribute torque to the four wheels to start driving straight.

In this embodiment, the present invention utilizes the feature that the torque of each wheel of a distributed drive vehicle can be independently controlled, instead of using a dedicated steering motor or a human driver as the power source for steering, it uses the forward or backward driving of each wheel. As the power source for steering, vehicle steering can be realized in a low-cost, simple and robust manner; the present invention can individually control the deflection angle of each steering wheel without establishing a physical connection between the two steering wheels; The overall steering movement, through the control of the different driving forces of each wheel, is more convenient to meet the overall steering, speed, and acceleration requirements of the vehicle; in the present invention, the deflection control element can be used to promote the steering of the vehicle through the driving force of the wheels, which can make the vehicle The steering is more convenient and quicker and saves costs.

The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

A vehicle steering method, characterized in that it is used for distributed driving control of the wheels, including: the steering wheel is directly or indirectly applied to the steering wheel by the distributed driving power source directly or indirectly, so that the steering wheel and the contact surface are generated Driving force, the driving force generates a rotational torque T rotation on the steering shaft of the steering wheel, and after overcoming the frictional resistance torque between the steering wheel and the steering shaft, and the steering wheel and the contact surface, causes the steering wheel to rotate around the steering shaft of the wheel.
The vehicle steering method according to claim 1, characterized by comprising:

A deflection moment T bias around the steering axis of the steering wheel is set. This moment generates a corresponding torque that makes the wheel reach a stable state when the wheel deviates to a desired position to form a stable steering.
The vehicle steering method according to claim 2, characterized by comprising:

When the wheel is in a yaw state, the yaw moment can change correspondingly with the change of the wheel yaw angle, and the direction of the rotation moment is always opposite when the wheel is yaw.
The vehicle steering method according to claim 2, characterized by comprising:

Before the wheel is deflected to the desired position, the yaw moment is any torque value that allows the wheel to deflect; when the wheel is turned to the desired position, the yaw moment will be set to the torque that can maintain the wheel at this position.
The vehicle steering method according to any one of claims 2 to 4, characterized in that it comprises:

Choose at least one point B as the force application point B that generates the deflection moment, set the joints OA and AB as rigid bodies, point O as the geometric center of the wheel, point A as the turning point when point O rotates around the steering axis of the wheel, and point B as the generating point The force application point of the deflection moment,

A deformable deflection control element is provided between at least one connection point B and the vehicle body. When the wheel is pointing straight ahead, the deflection control element is in a free state, and does not generate tension or pressure. When the wheel is deflected by applying force , deflection control element is stretched and a tensile force F to pull / pressure or compression force F is generated, controls the steering wheel about the steering wheel shaft.
The vehicle steering method of claim 5, wherein:

Deflection control element is stretched to produce tensile force F is generated about the yaw bias stabilizing wheel torque T of the steering shaft, its rotating balance and rotational torque T, blocking resistance torque T, the steering wheel deflection angle can be maintained stable;

If the drive torque T cancel or reduce flooding, the driving force F and the rotational torque T will disappear or decrease the spin moment about the steering shaft will no longer form the balance wheel in a positive drive force F to pull the next time.
The vehicle steering method according to claim 5 or 6, characterized in that it comprises:

Deflection control element is compressed to generate the pressure force F, which is generated when the steering wheel about the axis of yaw moment and the rotational torque T T equilibrium partial rotation, the drag torque T can maintain a stable hindered wheel deflection angle; canceled or reduced when driving Torque T drives , the driving force F and T spin will disappear or decrease, and the wheels will return to normal under the F pressure .
The vehicle steering method according to claim 1, characterized by comprising:

According to the vehicle dynamics balance, consider at least one of the driving force, resistance, and centrifugal force of the vehicle, and comprehensively consider the steering demand, calculate the driving force of each wheel in various motion states of the vehicle, and execute the mechanism to the driving force in real time And/or the braking force actuator output command.
The vehicle steering method according to claim 4, characterized by comprising:

Change the stiffness of the deflection control element through the electronic control device, or change the length of the deflection control element through the electronic control structure to indirectly generate the torque T deflection , so that the wheel maintains a stable deflection angle,

When the wheels need to return to the center, the steering wheel's driving torque is adjusted to make it automatically return to the center, or the active deflection control element provides the centering torque.
The vehicle steering method according to claim 1, characterized by comprising:

When the required torque of the steering wheel is opposite to the direction of rotation of the wheel, the steering wheel can be selected to provide the braking system or be directly or indirectly applied by the steering wheel by the distributed driving power source to realize the steering.
A vehicle steering system, characterized in that, by separately driving and controlling each wheel that needs to be steered to be controlled, the deflection angle of the steering wheel is individually controlled, including:

Distributed driving power source: used to provide steering force for steering wheels;

At least one steering wheel: used to receive the direct or indirect force of the distributed driving power source, and generate driving force between the steering wheel and the contact surface;

The steering shaft of the steering wheel: provides a rotating support for the deflection of the steering wheel;

Control: calculating a distributed power source for driving force directly or indirectly to the size, such that rotation of the rotational torque T generated partial yaw moment T, T drag torque resistance balance, the deflection of the steering wheel; and / or calculated vehicle The overall dynamic balance, including at least one of the driving force, resistance, and centrifugal force, enables the vehicle to achieve the desired state of motion.
The vehicle steering system according to claim 11, further comprising:

The yaw control element is used to generate a yaw moment T bias around the steering axis of the steering wheel. This moment generates a corresponding moment to make the wheel reach a stable state when the wheel deflects to a desired position to form a stable steering.
The vehicle steering system according to claim 12, wherein the yaw moment generating device further comprises:

Choose at least one point B as the force application point B that generates the deflection moment, set the joints OA and AB as rigid bodies, point O as the geometric center of the wheel, point A as the turning point when point O rotates around the steering axis of the wheel, and point B as the generating point The force application point of the deflection moment,

At least one deformable deflection control element is provided between the connection point B and the vehicle body. When the wheel is pointing straight ahead, the deflection control element is in a free state, and does not generate tension or pressure. When the wheel is deflected by applying force, The deflection control element is stretched to generate a tensile force F pull or/and compressed to generate a pressure F pressure , and controls the steering wheel to rotate around the steering shaft of the wheel.
The vehicle steering system according to claim 13, wherein the deflection control element further comprises: a plurality of AB rigid bodies are respectively arranged at the connection with the rigid body of the OA, and the plurality of AB are respectively connected to the deflection control element.
The vehicle steering system of claim 13, wherein the control center further comprises:

When the active deflection control element is used, according to the input of the deflection angle and the vehicle motion state, the characteristic targets including the stiffness and the length required for the deflection torque generator are obtained.
A steering method of a traveling mechanism, which is characterized in that the traveling mechanism including at least four wheels matches torque to achieve a set driving mode:

The deflection angle of each steering wheel can be controlled separately, and there is no need to establish a physical connection between the two steering wheels,

For the overall steering motion of the vehicle, by controlling the different driving forces of the steering wheels, the steering centers of the two rear wheels are on the extension line of the rear axle, and the steering centers of the two front wheels intersect at the same point on the extension line of the rear axle.

The steering wheel controls the steering in the following way: the steering wheel is directly or indirectly applied by the distributed driving power source to the required torque for steering alone, so that a driving force is generated between the steering wheel and the contact surface, and the driving force generates the rotation of the steering shaft of the steering wheel The torque T rotates and overcomes the frictional resistance moment between the steering wheel and the steering shaft, and the steering wheel and the contact surface, causing the steering wheel to rotate around the steering shaft of the wheel. The resistance torque includes the steering wheel about the steering shaft and the steering wheel contacting The frictional resistance moment of the surface.
The steering method of a traveling mechanism according to claim 16, characterized in that it comprises:

When the torque required for the steering wheel is opposite to the direction of rotation of the wheel, it can also be provided by the braking system.
The steering method of a traveling mechanism according to claim 16, characterized by comprising:

The inner steering wheel needs a contact surface to give the steering wheel a driving force toward the rear of the vehicle; for the outer steering wheel, a forward driving force is required.
The steering method of a traveling mechanism according to claim 18, characterized in that it comprises:

The driving torque or braking torque in different directions is applied to the two wheels of the rear axle for matching, so as to realize the stable advancement of the vehicle in the desired motion mode.
The steering method of the traveling mechanism according to claim 16, characterized in that it comprises: setting a yaw moment T yaw around the steering axis of the steering wheel, and this moment generates a corresponding moment for the wheel to reach a stable state when the wheel deflects to a desired position, To form a stable turn.
The vehicle steering method according to claim 20, characterized by comprising:

When the wheel is in a yaw state, the yaw moment can change correspondingly with the change of the wheel yaw angle, and the direction of the rotation moment is always opposite when the wheel is yaw.
The vehicle steering method according to claim 20, characterized by comprising:

Before the wheel is deflected to the desired position, the yaw moment is any torque value that allows the wheel to deflect; when the wheel is turned to the desired position, the yaw moment will be set to the torque that can maintain the wheel at this position.
The vehicle steering method according to any one of claims 20 to 22, characterized in that it comprises:

Choose at least one point B as the force application point B that generates the deflection moment, set the joints OA and AB as rigid bodies, point O as the geometric center of the wheel, point A as the turning point when point O rotates around the steering axis of the wheel, and point B as the generating point The force application point of the deflection moment,

A deformable deflection control element is provided between at least one connection point B and the vehicle body. When the wheel is pointing straight ahead, the deflection control element is in a free state, and does not generate tension or pressure. When the wheel is deflected by applying force , deflection control element is stretched and a tensile force F to pull / pressure or compression force F is generated, controls the steering wheel about the steering wheel shaft.
The vehicle steering method according to claim 16, characterized by comprising:

According to the vehicle dynamics balance, considering at least one of the driving force, resistance, and centrifugal force, calculate the driving force of each wheel in various motion states of the vehicle, and output it to the driving force actuator and/or braking force actuator in real time instruction.
A traveling mechanism includes the vehicle steering system described in 9-15.