Active steering system and vehicle

Abstract

The active steering system and vehicle provided by the embodiments of the present disclosure, the active steering system includes: a steering drive motor; a worm gear connected to the output end of the steering drive motor; a worm wheel meshing with the worm gear, and the worm wheel drives the wheels to turn through an axle; and a steering drive motor controller configured to convert a rotation signal of the steering drive motor obtained from a desired rotation angle signal and a real-time rotation angle signal of the wheels. The active steering system further includes: in-wheel motors arranged at both sides of the wheels and corresponding in-wheel motor controllers, and the in-wheel motor controllers are configured to convert a rotation signal of the corresponding in-wheel motor obtained from a desired rotation angle signal and a real-time rotation angle signal of the corresponding side wheels. At this time, the steering drive motor controller is configured to calculate the difference between the rotation signals of the in-wheel motors on both sides. The vehicle includes the active steering system. The active steering system and vehicle provided by the embodiments of the present disclosure have a simple structure and strong anti-interference ability.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of vehicle steering, and in particular, relates to an active steering system and a vehicle having the active steering system. Background Art

[0002] At present, the research on automobile active steering system is mainly divided into three categories: first, active steering system using electric power steering; second, electric servo hydraulic active steering system based on hydraulic power steering machine; third, hydraulic active steering system based on solenoid valve. Among them, the first type of active steering system using electric power steering is mainly suitable for smaller passenger cars, the second type of hydraulic power steering system is mainly suitable for commercial vehicles, and the third type of solenoid valve hydraulic active steering system is mainly used for engineering vehicles.

[0003] The hydraulic power steering structure involves components such as steering valves, hydraulic pumps, and hydraulic pipelines. The device is in operation during the entire operation of the vehicle, especially during low-speed and large-scale steering. The steering system requires a hydraulic pump to provide greater power, resulting in high energy consumption, complex hydraulic pipeline structure, and more control oil valves. The maintenance cost is high, and the long-term high-pressure state of the oil circuit also affects the service life of the entire steering system to a certain extent. The electric hydraulic power steering system also has similar problems.

[0004] Compared with the hydraulic active steering system, the electric steering system does not require a hydraulic power-assisting part, which shortens the power transmission process, but the steering system still has a series of steering devices. To address this problem, scholars later studied and adopted a skid steering solution, that is, removing the existing steering mechanism and directly using a hub motor to drive the steering wheel, relying on the vehicle wheel speed difference or torque difference to achieve steering, but this steering method has the problem of steering coordination control between the steering wheels. When the wheel steering is too flexible and the wheel is too large and has poor steering and coordination capabilities, it is easy to cause the wheel steering process to get stuck, which poses a certain safety hazard. At the same time, when affected by road unevenness, the steering wheel is prone to jumping and the steering angle is inaccurate, thereby reducing the vehicle's driving stability.

[0005] In response to the above problems, Yancheng Institute of Technology proposed a four-wheel steering independent steering mechanism based on motor drive. The steering structure uses multiple turbines to transmit power to achieve steering. This steering method successfully eliminates hydraulic steering and realizes the independence of the movement between the drive motor and the wheels. However, there are two problems with the structure of the present invention. First, the steering structure transmits power through multiple turbines, which reduces the power transmission efficiency, and the wear problem of multiple pairs of gears also increases the subsequent maintenance cost of the system; second, the steering structure introduces different turning angle modes for different turning angle sizes, but does not explain the switching between steering modes and the smoothness of the transition. Therefore, the reliability and stability of the steering during the steering mode switching process remain to be discussed. Summary of the invention

[0006] The present disclosure aims to solve one of the above-mentioned problems.

[0007] To this end, the first aspect of the present disclosure provides an active steering system with a simple structure and strong anti-interference ability, including:

[0008] Steering drive motor;

[0009] A worm gear connected to an output end of the steering drive motor;

[0010] A worm wheel meshing with the worm, the worm wheel driving the wheel to turn through the axle; and

[0011] The steering drive motor controller is configured to obtain a rotation signal of the steering drive motor according to a desired steering angle signal and a real-time steering angle signal of the wheel.

[0012] The active steering system provided by the first embodiment of the present disclosure has the following characteristics and beneficial effects:

[0013] The active steering system provided by the embodiment of the first aspect of the present disclosure is a whole-bridge electric drive steering system based on a worm gear. The embodiment of the first aspect of the present disclosure uses a motor to directly drive the worm gear to achieve steering, avoiding complex hydraulic devices and related components such as steering wheels, and simplifying the steering structure; the embodiment of the first aspect of the present disclosure uses the reverse self-locking ability of the worm gear to solve the problem that the sliding steering mechanism has poor anti-interference ability to cope with the road surface. At the same time, the worm gear transmission is equivalent to the spiral transmission and the multi-tooth meshing transmission, which has the advantages of smooth transmission and low noise, and increases the safety and stability of the steering process; the characteristic of the worm gear to achieve a larger transmission ratio is used to achieve the effect of deceleration and torque increase in the steering process, and improve the power transmission efficiency of the entire steering process.

[0014] In some embodiments, the output end of the steering drive motor is connected to the worm gear through a coupling.

[0015] In some embodiments, worm teeth meshing with the worm wheel are provided only on the periphery of the worm within the range of the central angle α, where α is twice the maximum rotation angle of the wheel.

[0016] In some embodiments, the friction angle of the worm is smaller than the helix angle of the worm.

[0017] In some embodiments, the steering drive motor is connected to the vehicle frame.

[0018] In some embodiments, the active steering system provided by the first aspect of the present disclosure also includes: wheel-side motors and corresponding wheel-side motor controllers arranged at the wheels on both sides, the wheel-side motor controllers being configured to obtain corresponding measured rotation signals of the wheel-side motors according to the desired steering angle signals and real-time steering angle signals of the corresponding side wheels, and the steering drive motor controller being configured to obtain the difference between the rotation signals of the wheel-side motors on both sides.

[0019] The vehicle provided in the embodiment of the second aspect of the present disclosure is provided with an active steering system as described in any one of the embodiments of the first aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 and Figure 2 They are respectively a top view and a side view of a first active steering system provided in an embodiment of the first aspect of the present disclosure.

[0021] Figure 3 for Figure 1 Cross-section through a worm gear in an active steering system shown.

[0022] Figure 4 for Figure 1 The control block diagram of the active steering system is shown.

[0023] Figure 5 and Figure 6 They are respectively a top view and a side view of a second active steering system provided in an embodiment of the first aspect of the present disclosure.

[0024] Figure 7 for Figure 5 The control block diagram of the active steering system is shown.

[0025] In the figure:

[0026] 100-active steering system, 110-steering drive motor, 120-worm, 130-worm gear, 140-axle, 150-wheel, 160-subframe, 170-body, 180-wheel-side motor. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0028] On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the detailed description of the present application below. Those skilled in the art can fully understand the present application without the description of these details.

[0029] The first aspect of the present disclosure provides a pure electric full-bridge steering system for commercial vehicles, which is a full-bridge steering system based on a worm gear. The steering system is applied to unmanned commercial vehicles with multi-axis steering. There is no requirement for the steering system's self-centering ability, operational sensitivity, and the driver's road feel. Therefore, a series of mechanisms such as the steering wheel and steering control are removed, the steering system device is simplified, the power transmission process is shortened, and the power transmission efficiency is improved.

[0030] See also Figure 1 , Figure 2 (The dotted line in the figure indicates the center axis of the vehicle). The first active steering system 100 provided by the first embodiment of the present disclosure is suitable for high-power power supply vehicles, including:

[0031] Steering drive motor 110;

[0032] A worm 120, wherein the worm 120 is connected to an output end of the steering drive motor 110;

[0033] A worm wheel 130 , which is meshed with the worm 120 , and drives the wheel 150 to turn through the axle 140 ; ​​and

[0034] The steering drive motor controller (the controller is not shown in the figure) is configured to obtain a rotation signal of the steering drive motor 110 according to the desired steering angle signal and the real-time steering angle signal of the wheel.

[0035] In some embodiments, the output end of the steering drive motor 110 is connected to the end of the worm 120 through a coupling, so as to provide power to the worm 120 to drive the worm 120 to rotate. Optionally, the steering drive motor 110 is mounted on the vehicle frame. The steering drive motor 110 can be selected according to the type of vehicle to be actually used. For a high-power power supply vehicle, a DC motor with a fixed magnetic field can be selected, and the magnet fixed in the magnet housing is integrated with the worm 120, and the other end of the worm 120 is mounted on the entire vehicle frame through a bearing.

[0036] In some embodiments, the worm 120 and the worm wheel 130 are meshed, and the worm wheel 130 is fixedly connected to the axle to transmit the power provided by the steering drive motor 110 to the axle 140, and then the axle 140 drives the wheel 150 to steer. Figure 3The worm teeth meshing with the turbine 130 are only provided on the periphery of the worm 120 within the range of the central angle α, and α should be twice the maximum rotation angle of the wheel.

[0037] In some embodiments, the controller is used to obtain a rotation signal of the steering drive motor 110 according to the desired steering angle signal of the vehicle and the wheel steering angle signal measured in real time, and the steering drive motor 110 is controlled by the rotation signal. Figure 4 The vehicle control unit calculates the expected steering angle signal of the wheel according to the current driving state of the vehicle, and infers the expected rotation angle of the steering drive motor 110 according to the expected steering angle signal, and transmits the rotation angle to the steering drive motor controller to control the steering drive motor 110 to rotate a certain angle. At the same time, the angle of rotation of the steering drive motor 110 is read through the encoder and fed back to the steering drive motor controller as a feedback signal, and the rotation of the steering drive motor 110 is further adjusted until the actual rotation angle of the steering drive motor 110 is consistent with the expected rotation angle.

[0038] Figure 1 , Figure 2 The active steering system shown is mainly suitable for high-power power supply vehicles, where the steering drive motor 110 drives the axle 140 to steer, thereby realizing the steering of the wheel 150. The specific working process is: the vehicle control unit sends the desired turning angle signal of the vehicle to the controller, and the controller controls the rotation of the steering drive motor 110, thereby driving the worm 120 to rotate. A worm gear 130 is installed between the axle 140 and the frame 160. The axle 140 can rotate relative to the frame 160 around an axis perpendicular to the ground. The worm gear 130 and the axle 140 are fixedly connected, driving the axle 140 to rotate together. The radial dimension design requirement of the worm gear 130 is large so that it can withstand the pitch and roll loads of the vehicle body 170. There are worm teeth at the local periphery of the worm gear 130. The driving force is transmitted to the worm gear 130 through meshing with the worm 110 to further drive the steering of the axle 140. There is no steering kingpin between the wheel 150 and the axle 140. The wheel 150 always remains perpendicular to the steering axle. The overall steering of the axle 140 drives the wheel 150 to achieve steering, and the wheel angle is equal to the axle angle. The friction angle of the worm 120 is set to be smaller than the helix angle of the worm 120 to ensure the reverse self-locking effect between the worm wheel 130 and the worm 120, thereby ensuring the anti-interference ability of the steering system to road unevenness.

[0039] See also Figure 5 , Figure 6The difference between the second active steering system provided in the first aspect of the embodiment and the first active steering system is that the second active steering system also includes a wheel-side motor 180 arranged at the wheel. Due to the presence of the wheel-side motor 180, the active steering system reduces the power requirement for the steering drive motor 110 (in this case, the steering drive motor 110 can use a DC motor or a servo motor), and the entire steering process realizes the steering of the axle 140 through coordination between the steering drive motor 110 and the wheel-side motor 180. That is, when the vehicle is not turning, the steering drive motor 110 does not output torque, and the reverse self-locking ability of the worm gear is used to resist the rotation of the axle 140 around the worm gear 130 caused by the unbalanced driving force of the wheel motors 180 on both sides of the axle 140 and the unevenness of the road surface; when the vehicle is turning, the driving torque difference of the wheel motors 180 on both sides is used to obtain the required unequal longitudinal reaction force on the left and right from the ground, and apply a differential steering torque to the axle 140; due to the reverse self-locking effect of the worm gear, the differential steering torque cannot turn the axle 140, thereby increasing the anti-disturbance ability of the train vehicle during the turning process; the reverse self-locking is unlocked by the power input from the steering drive motor 110 on the worm gear 120 side, so that the axle 140 can turn under the action of the above-mentioned differential steering torque. The steering drive motor 110 is positionally servo-controlled according to the desired steering angle signal of the wheel to achieve the desired steering angle, thereby ensuring the stability and accuracy of the vehicle steering process.

[0040] See also Figure 7 The steering process of the active steering system is as follows: the vehicle control unit outputs the desired steering angle signal of the vehicle to the steering drive motor controller and the wheel motor controller, and the wheel motor 180 generates a differential steering torque, and the target steering angle is achieved through the servo control of the steering drive motor 110. Specifically, the vehicle control unit calculates the desired steering angle signal of the controlled wheel (such as Figure 7 As shown in , δ1 is the desired steering angle signal of the left wheel output by the vehicle control unit, and δ3 is the desired steering angle signal of the right wheel output by the vehicle control unit). The desired rotation angle of the steering drive motor 110 is calculated based on the desired steering angle signal, and the desired steering angle signal of the controlled wheel is transmitted to the corresponding wheel-side motor controller, and the desired rotation angle of the steering drive motor 110 is transmitted to the steering drive motor controller. The wheel-side motors on both sides of the vehicle rotate a certain angle, and the steering drive motor synchronously drives the worm gear to rotate. At this time, the rotation angle of the encoder corresponding to the wheel-side motor is read (such as Figure 7As shown in , δ1' and δ3' are the rotation angles of the left wheel motor encoder and the right wheel motor encoder, respectively, and δ2' is the rotation angle of the steering drive motor encoder), and the rotation angle is fed back to the corresponding wheel motor controller and the steering drive motor controller as a feedback signal, and the rotation of the corresponding wheel motor and the steering drive motor is adjusted until the rotation angles of the corresponding wheel motor and the steering drive motor are consistent with their respective expected rotation angles. This steering system solution not only reduces the power demand for the steering drive motor 110, but also improves the anti-interference ability of the active steering system to road unevenness due to the reverse self-locking ability between the worm 120 and the worm wheel 130, thereby ensuring the accuracy of the vehicle steering angle.

[0041] To sum up, the active steering system provided by the embodiment of the first aspect of the present disclosure not only reduces the traditional steering wheel, hydraulic power system and other devices, and reduces maintenance costs; it also shortens the steering power transmission process, and improves steering efficiency and steering flexibility; at the same time, since the steering system adopts worm gear steering, the reverse self-locking ability of the worm gear further avoids the vehicle steering instability problem caused by the interference of external road roughness, and the large transmission ratio structure of the worm gear further plays a role in reducing speed and increasing torque, thereby increasing steering power and improving steering accuracy.

[0042] The vehicle provided in the second embodiment of the present disclosure comprises the active steering system provided in the first embodiment of the present disclosure.

[0043] Furthermore, when the active steering system provided by the embodiment of the first aspect of the present disclosure is used in commercial vehicles, trains, and trailers, the inner wheel difference can be reduced and the driving stability of the vehicle can be improved.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0045] Although embodiments of the present disclosure have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. An active steering system, characterized in that, comprising: a steering drive motor; a worm, the worm being connected to the output end of the steering drive motor; a worm gear, the worm gear meshing with the worm and being fixedly connected to the axle, there is no kingpin between the axle and the wheels on both sides thereof, that is, the wheels always remain perpendicular to the axle, the worm gear drives the wheels on both sides of the axle to turn through the overall turning of the axle, and the wheel turning angle is equal to the axle turning angle; and a steering drive motor controller, configured to realize the turning of the axle through the coordination between the turning signal of the steering drive motor obtained by converting the desired turning angle signal and the real-time turning angle signal of the wheels and the longitudinal reaction force difference between the steering drive motor and the two sides of the wheels; only on the periphery of the worm gear within the central angle α, there are worm teeth meshing with the worm, α being twice the maximum turning angle of the wheels.

2. The active steering system according to claim 1, characterized in that, the output end of the steering drive motor is connected to the worm through a coupling.

3. The active steering system according to claim 1, characterized in that, the friction angle of the worm is less than the helix angle of the worm.

4. The active steering system according to claim 1, characterized in that, the steering drive motor is connected to the vehicle frame.

5. The active steering system according to claim 1, characterized in that, the active steering system further comprises: wheel motors and corresponding wheel motor controllers provided at both sides of the wheels, the wheel motor controllers are configured to obtain the rotation signals of the corresponding wheel motors on the corresponding sides by converting the desired turning angle signals and the real-time turning angle signals of the corresponding side wheels, and the steering drive motor controller is configured to be the difference between the rotation signals of the two side wheel motors.

6. A vehicle, characterized in that, the vehicle comprises the active steering system according to any one of claims 1 to 5.

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