CN111252142B - Automobile frame with adjustable turning radius and control method - Google Patents

Abstract

The invention discloses an automobile frame with an adjustable turning radius and a control method, wherein the automobile frame comprises a left longitudinal beam and a right longitudinal beam, each longitudinal beam is provided with a set of rotating mechanism, and each set of rotating mechanism comprises two independent control motors, two sets of locking mechanisms, two sets of ball screws, two sets of rotating arms and a rotating shaft connected between the two sets of rotating arms; the longitudinal beam is arranged in a tubular inner cavity of the rotating arm; the control motor is installed on the longeron, control motor's output shaft ball, install the nut base on the rotor arm, install locking mechanism between ball and control motor for carry out the locking to ball. The invention can actively control and adjust the turning radius of the automobile when the automobile is in understeer or oversteer to influence the steering stability of the automobile, thereby ensuring the running safety of the automobile and reducing the driving difficulty of the driver.

Description

Automobile frame with adjustable turning radius and control method

Technical Field

The invention relates to the field of modern automobile design and manufacturing, and in particular to an automobile frame with adjustable turning radius and a control method thereof.

Background technique

The minimum turning radius of a car refers to the radius of the track circle that the center plane of the outer steering wheel rolls on the supporting plane when the steering wheel is turned to the extreme position and the car is turning at the lowest stable speed. The minimum turning radius of a car mainly affects the maneuverability of the car when driving. The smaller the minimum turning radius, the better the maneuverability of the car and the smaller the space required for turning. The minimum turning radius of a traditional car is mainly affected by the maximum value of the outer steering wheel deflection angle and the wheelbase. The smaller the maximum value of the outer steering wheel deflection angle or the longer the wheelbase, the larger the minimum turning radius. However, these two parameters are determined by the structure and shape of the car and are usually not easy to adjust. In addition, since the turning radius of the car is usually mainly controlled by the deflection angle of the front wheel when turning, the steering characteristics of the car are generally not easy to adjust when the driver realizes the steering.

At present, the number of cars is increasing year by year, and the road conditions are becoming more and more complicated, which increases the difficulty of driving, especially in traffic jams or parking. The requirements for the maneuverability of cars are also gradually increasing. When the car is turning at high speed, in order to improve the handling stability of the car, a safety device that can automatically assist in controlling the turning radius of the car is very necessary.

Summary of the invention

The purpose of the present invention is to provide a car frame with adjustable turning radius and a control method, which can cleverly and reasonably achieve the minimum turning radius required by the car, solve the problem of insufficient steering or excessive steering of the car affecting the handling stability of the car, and actively control and adjust the turning radius of the car.

The technical solution adopted by the present invention is: a car frame with an adjustable turning radius, including two left and right longitudinal beams, each longitudinal beam has a set of rotating mechanisms, each set of rotating mechanisms includes two sets of independent control motors, two sets of locking mechanisms, two sets of ball screws, two sets of rotating arms and a rotating shaft connected between the two sets of rotating arms; the longitudinal beam is installed in the tubular inner cavity of the rotating arm; the control motor is installed on the longitudinal beam, the output shaft of the control motor is connected to the ball screw, a nut base is installed on the rotating arm, which is used to cooperate with the ball screw to control the telescopic distance between the rotating arm and the longitudinal beam, and a locking mechanism is installed between the ball screw and the control motor to lock the ball screw.

Furthermore, the locking mechanism consists of a front slide rail, a rear slide rail and a locking device, the front slide rail is connected to the control motor housing, and the rear slide rail is connected to the nut bracket in the ball screw. The front and rear slide rails can move synchronously with the movement of the longitudinal beam and the rotating arm.

Furthermore, the locking device is driven by an electromagnetic device and can realize locking or unlocking control according to a locking signal from the ECU.

A method for controlling a vehicle frame with an adjustable turning radius comprises the following steps:

The frame control system ECU estimates the driver's intended driving route through the steering wheel angle sensor and wheel speed sensor measurements;

Calculate the actual driving route of the current vehicle through the measurement values of the yaw angular velocity sensor, the measurement values of the longitudinal acceleration sensor and the measurement values of the lateral acceleration sensor;

By calculating the difference between the driving intention route and the actual driving route, it is determined whether the current steering is a neutral steering;

If it is judged to be a neutral turn, the current state of the frame is maintained;

If it is not a neutral steering, continue to judge whether it is understeering or oversteering;

When it is judged as understeering, the steering direction of the vehicle continues to be judged;

If the vehicle is turning left, the front locking mechanism and the rear locking mechanism on the left longitudinal beam are all in the locked state, and the front control motor and the rear control motor on the right longitudinal beam rotate to adjust the relative distance between the corresponding front and rear rotating arms and the connected longitudinal beam to become longer;

If the vehicle turns right, the front locking mechanism and the rear locking mechanism on the right longitudinal beam are all in the locked state, and the front control motor and the rear control motor on the left longitudinal beam rotate, adjusting the relative distance between the corresponding front and rear rotating arms and the connected longitudinal beam to become longer;

If it is judged as excessive steering, the steering direction of the car will continue to be judged;

If the vehicle is turning left, the front locking mechanism and the rear locking mechanism on the left longitudinal beam are all in the locked state, and the front control motor and the rear control motor on the right longitudinal beam rotate to adjust the corresponding front and rear rotating arms to shorten the relative distance with the connected longitudinal beam;

If the vehicle is turning right, the front locking mechanism and the rear locking mechanism on the right longitudinal beam are all in the locked state, and the front control motor and the rear control motor on the left longitudinal beam rotate to adjust the corresponding front and rear rotating arms to shorten the relative distance between the connected longitudinal beams.

The beneficial effects produced by the present invention are:

The present invention is a new structure that can achieve the required minimum turning radius when the car is in extreme steering. The present invention will also actively control and adjust the turning radius of the car when the car understeers or oversteers, which affects the car's handling stability, so that the car can be driven according to the driver's intention, ensuring the car's driving safety and reducing the driving difficulty for the driver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a longitudinal beam on one side of the present invention;

FIG2 is a control judgment strategy diagram of the present invention;

In the figure: 1-front control motor, 2-front locking mechanism, 3-front ball screw, 4-front longitudinal beam, 5-front rotating arm, 6-rear control motor, 7-rear locking mechanism, 8-rear ball screw, 9-rear longitudinal beam, 10-rear rotating arm, 11-rotating shaft, 12-front slide rail, 13-rear slide rail, 14-locking device, 15-nut bracket.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

The frame is the base of the whole car. Different models usually use different forms of frames. According to different structural forms, the frames can be generally divided into three types: side beam frame, middle beam frame and integrated frame, among which the side beam frame is the most widely used. The present invention takes the side beam frame with adjustable minimum turning radius as the main object, but the structure and method adopted can also be applied to other types of frames.

The two longitudinal beams of the frame are usually rigid. The main feature of the frame structure proposed by the present invention is that the frame can achieve a certain turning angle, thereby changing the minimum turning radius value of the car. The difference between the present invention and the ordinary frame is that the longitudinal beam can be rotated around the vertical axis of the vehicle body, and the longitudinal beam length can be automatically adjusted to adapt to the different length changes of the longitudinal beams on both sides when rotating.

As shown in FIG1 , the frame longitudinal beam of the present invention no longer adopts the whole beam mode of the traditional automobile, but is divided into the front longitudinal beam 4 and the rear longitudinal beam 9 of the frame. The left longitudinal beam is used as an example to illustrate: the left front longitudinal beam 4 of the frame is installed in the tubular inner cavity of the left front rotating arm 5, and the two have the same axis. The left front longitudinal beam 4 can move freely in the axial direction relative to the left front rotating arm 5. The base of the left front control motor 1 is fixedly installed on the upper end of the left front longitudinal beam 4, and the output shaft of the left front control motor 1 is coaxially fixedly installed with the screw in the left front ball screw 3, and the screw is controlled to rotate by the left front control motor 1. The nut bracket 15 in the left front ball screw 3 is fixedly installed on the upper end of the left front rotating arm 5, so the left front longitudinal beam 4 and the left front rotating arm 5 can be driven to move relative to the axial direction of the two by rotating the screw in the left front ball screw 3. The left front locking mechanism 2 is composed of a front slide rail 12, a rear slide rail 13 and a locking device 14. The front slide rail 12 of the left front locking mechanism 2 is connected to the housing of the left front control motor 1, and the rear slide rail 13 of the left front locking mechanism 2 is connected to the nut bracket 15 in the left front ball screw 3. The front slide rail 12 and the rear slide rail 13 can move synchronously with the movement of the left front longitudinal beam 4 and the left front rotating arm 5. The function of the left front locking mechanism 2 is to ensure that the left front longitudinal beam 4 and the left front rotating arm 5 are locked when they move to the specified position and cannot deviate freely.

Similar to the above structure, the left rear longitudinal beam 9 of the frame is installed in the tubular inner cavity of the left rear rotating arm 10, and the two have the same axis. The left rear longitudinal beam 9 can move freely in the axial direction relative to the left rear rotating arm 10. The base of the left rear control motor 6 is fixedly installed on the upper end of the left rear longitudinal beam 9, and the output shaft of the left rear control motor 6 is coaxially fixedly installed with the screw in the left rear ball screw 8, and the screw is controlled to rotate by the left rear control motor 6. The nut bracket 15 in the left rear ball screw 8 is fixedly installed on the upper end of the left rear rotating arm 10, so the rotation of the screw in the left rear ball screw 8 can drive the left rear longitudinal beam 9 and the left rear rotating arm 10 to move relative to the axis direction of the two. The left rear locking mechanism 7 is composed of a front slide rail 12, a rear slide rail 13 and a locking device 14. The front slide rail 12 of the left rear locking mechanism 7 is connected to the housing of the left rear control motor 6. The rear slide rail 13 of the left rear locking mechanism 7 is connected to the nut bracket 15 in the left rear ball screw 8. The front slide rail 12 and the rear slide rail 13 can move synchronously with the movement of the left rear longitudinal beam 9 and the left rear rotating arm 10. The function of the left rear locking mechanism 7 is to ensure that the left rear longitudinal beam 9 and the left rear rotating arm 10 are locked when they move to the specified position and cannot deviate freely.

The locking device 14 is driven by an electromagnetic device and can realize locking or unlocking control according to the locking signal of the ECU.

The front rotating arm 5 and the rear rotating arm 10 in the rotating mechanism are connected by a rotating shaft 11, and the two can rotate freely around the rotating shaft 11. The position of the rotating mechanism on the longitudinal beam is usually determined according to the overall layout characteristics of the vehicle model, and this position is generally near the middle position of the longitudinal direction of the vehicle body.

The structure of the right longitudinal beam of the frame is similar to that of the left longitudinal beam, that is, the movement of the rotating mechanism is adjusted by the front and rear control motors on the left and right longitudinal beams of the side beam type frame respectively.

When the vehicle is traveling in a straight line, the front locking mechanism 2 and the rear locking mechanism 7 on the left and right longitudinal beams are all in a locked state. At this time, the rotating arm on one side cannot move along its axis relative to the front and rear longitudinal beams on the corresponding side, that is, the sum of the lengths of the longitudinal beam on one side and the rotating arm thereon will remain unchanged. In this locked state, due to the high rigidity of the frame, the frame will remain in a non-knee state, which is no different from a conventional frame.

When a car is turning at high speed, if understeering or oversteering occurs, affecting the handling stability, the frame control system ECU will continuously correct the deflection angle of the car frame to adjust the car's driving path.

In a car equipped with an adjustable turning radius car frame, in order to ensure that the car can freely adjust the minimum turning radius, the body parts in the horizontal vertical plane where the steering mechanism shaft is located can rotate with the operation of the steering mechanism, so that the car body forms a certain angle. Therefore, the side beams on both sides of the car body should adopt the form of a steering mechanism, but there is no need to set up control motors, locking mechanisms, ball screws, ball screws and other driving components. For the car top cover, a hinged form is required.

As shown in FIG2 , the frame control system ECU estimates the driver's driving intention route through the steering wheel angle sensor measurement value and the wheel speed sensor measurement value, and calculates the current actual driving route of the car through the yaw angular velocity sensor measurement value, the longitudinal acceleration sensor measurement value and the lateral acceleration sensor measurement value. By calculating the difference between the driving intention route and the actual driving route, it is determined whether the current steering is neutral steering. If it is determined to be neutral steering, the current state of the frame is maintained; if it is determined not to be neutral steering, it continues to determine whether it is understeering or oversteering. In the case of understeering, it is necessary to determine the working state of the rotating arm according to the current steering direction. If it turns to the left, the front locking mechanism 2 and the rear locking mechanism 7 on the left longitudinal beam are all in the locked state, and the front control motor 1 and the rear control motor 6 of the right longitudinal beam rotate, and the corresponding front and rear rotating arms 10 are adjusted to have a longer relative distance from the connected longitudinal beam; if it turns to the right, the front locking mechanism 2 and the rear locking mechanism 7 on the right longitudinal beam are all in the locked state, and the front control motor 1 and the rear control motor 6 of the left longitudinal beam rotate, and the corresponding front and rear rotating arms are adjusted to have a longer relative distance from the connected longitudinal beam. In this way, the vehicle's handling stability can be controlled without much change in the interior space of the vehicle.

Similarly, when it is judged that there is too much steering, the steering direction is still determined first. If it is a left turn, the front locking mechanism 2 and the rear locking mechanism 7 on the left longitudinal beam are all in a locked state, and the front control motor 1 and the rear control motor 6 of the right longitudinal beam rotate, and the relative distance between the corresponding front and rear rotating arms and the connected longitudinal beam is shortened; if it is a right turn, the front locking mechanism 2 and the rear locking mechanism 7 on the right longitudinal beam are all in a locked state, and the front control motor 1 and the rear control motor 6 of the left longitudinal beam rotate, and the relative distance between the corresponding front and rear rotating arms 10 and the connected longitudinal beam is shortened.

When the car is turning slowly at the limit, if the turning radius cannot meet the requirement, the current minimum turning radius needs to be reduced. The specific control is as follows: When the car turns left, all control motors are controlled at the same time to adjust the relative distance between the left front and rear rotating arms and the connected longitudinal beam to the shortest limit, and at the same time adjust the relative distance between the right front and rear rotating arms and the connected longitudinal beam to the longest limit. When the car turns right, all control motors are controlled at the same time to adjust the relative distance between the right front and rear rotating arms and the connected longitudinal beam to the shortest limit, and at the same time adjust the relative distance between the left front and rear rotating arms and the connected longitudinal beam to the longest limit.

Claims (1)

1. A control method of an automobile frame with adjustable turning radius is characterized by comprising the following steps: each longitudinal beam is provided with a set of rotating mechanism, and each set of rotating mechanism comprises two independent control motors, two sets of locking mechanisms, two sets of ball screws, two sets of rotating arms and a rotating shaft connected between the two sets of rotating arms; the longitudinal beam is arranged in a tubular inner cavity of the rotating arm; the control motor is arranged on the longitudinal beam, an output shaft of the control motor is connected with the ball screw, a nut base is arranged on the rotating arm and used for controlling the telescopic distance between the rotating arm and the longitudinal beam in a matched manner with the ball screw, and a locking mechanism is arranged between the ball screw and the control motor and used for locking the ball screw; the locking mechanism consists of a front sliding rail, a rear sliding rail and a locking device, wherein the front sliding rail is connected with a control motor shell, the rear sliding rail is connected with a nut bracket in a ball screw, and the front sliding rail and the rear sliding rail can synchronously move along with the movement of a longitudinal beam and a rotating arm; the locking device is driven by an electromagnetic device, and realizes locking or unlocking control according to a locking signal of the ECU;

The control method comprises the following steps:

The vehicle frame control system ECU estimates a driving intention route of a driver through a steering wheel rotation angle sensor measurement value and a wheel speed sensor measurement value;

Calculating the current actual running route of the automobile through the yaw rate sensor measurement value, the longitudinal acceleration sensor measurement value and the transverse acceleration sensor measurement value;

judging whether the current steering is neutral steering or not by calculating the difference value between the driving intention route and the actual driving route;

if the steering is judged to be neutral, the existing state of the frame is maintained;

if the steering is not neutral steering, continuing to judge whether the steering is insufficient steering or excessive steering;

when the steering is not enough, continuing to judge the steering direction of the automobile;

If the left steering is performed, the front locking mechanism and the rear locking mechanism on the left longitudinal beam are in a locking state, the front control motor and the rear control motor of the right longitudinal beam rotate, and the relative distance between the corresponding front rotating arm and the corresponding rear rotating arm and the connected longitudinal beam is adjusted to be longer;

If the vehicle turns right, the front locking mechanism and the rear locking mechanism on the right side longitudinal beam are in a locking state, the front control motor and the rear control motor of the left side longitudinal beam rotate, and the relative distance between the corresponding front rotating arm and the corresponding rear rotating arm and the connected longitudinal beam is adjusted to be longer;

when the steering direction is judged to be too much, continuing to judge the steering direction of the automobile;

If the left steering is performed, the front locking mechanism and the rear locking mechanism on the left longitudinal beam are in a locking state, the front control motor and the rear control motor of the right longitudinal beam rotate, and the relative distance between the corresponding front rotating arm and the corresponding rear rotating arm and the connected longitudinal beam is regulated to be shortened;

if the steering is rightward, the front locking mechanism and the rear locking mechanism on the right longitudinal beam are in locking states, the front control motor and the rear control motor of the left longitudinal beam rotate, and the relative distance between the corresponding front rotating arm and the corresponding rear rotating arm and the connected longitudinal beam is adjusted to be shortened.