阅读说明：本技术 车辆原地转向控制方法、自动驾驶控制系统及控制设备 (Vehicle pivot steering control method, automatic driving control system and control equipment ) 是由 张亭 徐成 张放 王肖 霍舒豪 李晓飞 张德兆 于 2021-08-10 设计创作，主要内容包括：本发明公开一种车辆原地转向控制方法、自动驾驶控制系统及控制设备。车辆原地转向控制步骤是：确定车辆原地转向的转动方向和车辆前轮的路点轨迹,路点轨迹中包含路点速度信息；根据转动方向调整车辆的挡位和车辆前轮的初始角度,根据路点轨迹、车辆前轮的速度和加速度确定车辆前轮的期望加速度；根据车辆前轮的速度和期望加速度确定所述车辆前轮的输出扭矩；根据所述输出扭矩控制所述车辆前轮沿着所述路点轨迹转动。本发明可以保证原地转向过程中的速度可控,起步和停车过程比较平稳,避免原地转向开始时加速度和加加速度较大的问题,可以提高车辆原地转向终点的位姿的控制精度。(The invention discloses a vehicle pivot steering control method, an automatic driving control system and control equipment. The vehicle pivot steering control steps are as follows: determining the rotation direction of the pivot steering of the vehicle and the waypoint track of the front wheels of the vehicle, wherein the waypoint track comprises waypoint speed information; adjusting the gear of the vehicle and the initial angle of the front wheel of the vehicle according to the rotating direction, and determining the expected acceleration of the front wheel of the vehicle according to the path point track, the speed and the acceleration of the front wheel of the vehicle; determining an output torque of a front wheel of the vehicle based on a speed of the front wheel and a desired acceleration; and controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque. The invention can ensure that the speed in the pivot steering process is controllable, the starting and stopping processes are relatively stable, the problem of large acceleration and jerk when the pivot steering is started is solved, and the control precision of the pose of the pivot steering end point of the vehicle can be improved.)

1. A vehicle pivot steering control method, comprising:

determining the rotation direction of the pivot steering of the vehicle and the waypoint track of the front wheels of the vehicle, wherein the waypoint track comprises waypoint speed information;

adjusting the gear of the vehicle and the initial angle of the front wheel of the vehicle according to the rotation direction;

determining a desired acceleration of the front wheels of the vehicle from the waypoint trajectory, the speed and the acceleration of the front wheels of the vehicle;

determining an output torque of a front wheel of the vehicle based on a speed of the front wheel and a desired acceleration;

and controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque.

2. The vehicle pivot steering control method according to claim 1, wherein the step of adjusting the gear of the vehicle and the initial angle of the front wheels of the vehicle according to the rotation direction specifically comprises:

if the rotation direction is leftward, adjusting the gear of the vehicle to be a forward gear and adjusting the initial angle of the front wheel of the vehicle to be a preset first angle leftward; if the rotation direction is rightward, adjusting the gear of the vehicle to be a reverse gear and adjusting the initial angle of the front wheel of the vehicle to be a preset first angle leftward;

alternatively, the first and second electrodes may be,

if the rotation direction is leftward, adjusting the gear of the vehicle to be a forward gear and adjusting the initial angle of the front wheel of the vehicle to be a preset first angle leftward; and if the rotating direction is rightward, adjusting the gear of the vehicle to be a forward gear and adjusting the initial angle of the front wheel of the vehicle to be a preset second angle rightward.

3. The vehicle pivot steering control method according to claim 1, wherein determining the desired acceleration of the front wheels of the vehicle based on the waypoint trajectory, the speed and the acceleration of the front wheels of the vehicle comprises:

selecting a first waypoint closest to the front wheels of the vehicle from the waypoint track;

determining a pre-aiming distance according to the speed and the acceleration of the front wheel of the vehicle and a preset minimum pre-aiming distance;

intercepting the pre-aiming distance along the waypoint track by taking the first waypoint as a starting point to obtain a pre-aiming point;

and determining the expected acceleration of the front wheel of the vehicle according to the speed of the aiming point, the speed and the acceleration of the front wheel of the vehicle.

4. The vehicle pivot steering control method according to claim 1, wherein determining the output torque of the front wheels of the vehicle based on the speed and the desired acceleration of the front wheels of the vehicle specifically comprises:

and determining output torque corresponding to the speed and the expected acceleration of the front wheels of the vehicle from the preset corresponding relation among the speed, the expected acceleration and the output torsion of the front wheels of the vehicle.

5. The vehicle pivot steering control method according to claim 4, wherein the determining of the output torque corresponding to the speed and the desired acceleration of the front wheel of the vehicle from the preset corresponding relationship among the speed, the desired acceleration and the output torque of the front wheel of the vehicle specifically comprises:

and searching for the expected output torque corresponding to the speed and the expected acceleration of the front wheels of the vehicle from the corresponding relation by adopting a two-dimensional linear interpolation algorithm according to the speed and the expected acceleration of the front wheels of the vehicle.

6. The vehicle pivot steering control method according to claim 1, wherein controlling the vehicle front wheels to turn along the waypoint locus in accordance with the output torque further comprises:

and determining whether the front wheel of the vehicle rotates to the end point of the waypoint track, and if so, controlling the front wheel of the vehicle to rotate back to a preset third angle.

7. The vehicle pivot steering control method according to claim 6, characterized by further comprising:

before the front wheels of the vehicle are determined to rotate to the end point of the road point track, if an obstacle suddenly stops, the pivot steering is determined to fail;

and/or determining that the eps is failed and determining that the pivot steering fails during the control of the front wheel of the vehicle to return to the preset third angle.

8. The vehicle pivot steering control method according to claim 6, wherein determining whether the front wheels of the vehicle are turned to the end of the waypoint trajectory specifically comprises:

selecting a second waypoint closest to the front wheels of the vehicle from the waypoint track;

calculating the distance between the second waypoint and the endpoint of the waypoint track;

and if the distance is smaller than a preset distance threshold value, determining that the front wheel of the vehicle rotates to the end point of the waypoint track.

9. An automatic driving control system is characterized by comprising a planning decision module, a transverse control module and a longitudinal control module;

the planning decision module is used for determining the rotation direction and the waypoint track of the front wheels of the vehicle when the need of pivot steering is determined, and sending pivot steering indication information to the longitudinal control module and the transverse control module, wherein the waypoint track comprises waypoint speed information;

the transverse control module is used for adjusting the initial angle of the front wheels of the vehicle when the pivot steering indication information is received;

the longitudinal control module is used for adjusting the gear of the vehicle according to the rotating direction when the pivot steering indication information is received and the transverse control module finishes adjusting the initial angle of the front wheels of the vehicle; determining a desired acceleration of the front wheels of the vehicle from the waypoint trajectory, the speed and the acceleration of the front wheels of the vehicle; determining an output torque of a front wheel of the vehicle based on a speed of the front wheel and a desired acceleration; and controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque.

10. The autopilot control system of claim 9 wherein the longitudinal control module adjusts a gear of the vehicle based on the direction of rotation, specifically comprising:

if the rotation direction is leftward, when the front wheel of the vehicle turns leftward to a first angle, the gear of the vehicle is adjusted to be a forward gear; if the rotating direction is rightward, when the front wheel of the vehicle rotates to a first angle leftward, the gear of the vehicle is adjusted to be a reverse gear;

or if the rotation direction is leftward, when the front wheel of the vehicle turns leftward to a first angle, the gear of the vehicle is adjusted to be a forward gear; and if the rotating direction is rightward, when the front wheel of the vehicle rotates to a second angle rightward, adjusting the gear of the vehicle to be a forward gear.

11. The autopilot control system of claim 9 wherein the longitudinal control module determines a desired acceleration of the vehicle front wheels based on the waypoint trajectory, the speed and acceleration of the vehicle front wheels, including in particular:

selecting a first waypoint closest to the front wheels of the vehicle from the waypoint track;

determining a pre-aiming distance according to the speed and the acceleration of the front wheel of the vehicle and a preset minimum pre-aiming distance;

intercepting the pre-aiming distance along the waypoint track by taking the first waypoint as a starting point to obtain a pre-aiming point;

and determining the expected acceleration of the front wheel of the vehicle according to the speed of the aiming point, the speed and the acceleration of the front wheel of the vehicle.

12. The autopilot control system of claim 9 wherein the longitudinal control module determines the output torque of the vehicle front wheels based on the speed and the desired acceleration of the vehicle front wheels, including in particular:

and determining output torque corresponding to the speed and the expected acceleration of the front wheels of the vehicle from the preset corresponding relation among the speed, the expected acceleration and the output torsion of the front wheels of the vehicle.

13. The autopilot control system of claim 9 wherein the longitudinal control module is further configured to determine whether the front wheel of the vehicle has rotated to an end of the waypoint trajectory during the controlling of the front wheel of the vehicle to rotate along the waypoint trajectory based on the output torque, and if so, to send a turn back indication to the lateral control module;

the lateral control module is further configured to control the front wheels of the vehicle to rotate back to a preset third angle upon receiving a turn-back indication.

14. The autopilot control system of claim 13 wherein the longitudinal control module is further configured to determine a pivot steering failure if there is an obstacle scram prior to determining that the front wheels of the vehicle are turning to the end of the waypoint trajectory; and/or determining that the eps fails if the eps is determined to fail during the process of the lateral control module controlling the front wheels of the vehicle to turn back to the preset third angle.

15. The autopilot control system of claim 13 wherein the longitudinal control module determines whether the front wheels of the vehicle are turning to the end of the waypoint trajectory, including in particular:

selecting a second waypoint closest to the front wheels of the vehicle from the waypoint track;

calculating the distance between the second waypoint and the endpoint of the waypoint track;

and if the distance is smaller than a preset distance threshold value, determining that the front wheel of the vehicle rotates to the end point of the waypoint track.

16. A control device comprising at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the vehicle pivot steering control method of any one of claims 1-8.

17. A computer-readable storage medium characterized by comprising a program or instructions for implementing the vehicle pivot steering control method according to any one of claims 1 to 8 when the program or instructions are run on a computer.

18. A computer program product comprising instructions for causing a computer to perform the vehicle pivot steering control method of any one of claims 1-8 when the computer program product is run on the computer.

19. A vehicle characterized by comprising the control apparatus according to claim 16.

Technical Field

The invention relates to the technical field of vehicle steering control, in particular to a vehicle pivot steering control method, an automatic driving control system and control equipment.

Background

In order to enable the unmanned floor washing machine to cover a larger washing area, the front wheel of the unmanned floor washing machine has a larger steering range which is approximately-180 degrees. On the basis, the in-situ steering function can be realized without a floor washing machine, and the flexibility of the floor washing machine is greatly improved. In the conventional ackermann steering robot, a PID (proportional integral differential) control method based on a heading deviation is mostly adopted for in-situ steering control, a difference between a current heading and a target heading of a vehicle is used as PID control input, and the heading deviation is reduced by controlling the direction and speed of a front wheel, so that in-situ steering control of the robot is realized. The pivot steering control can cause that the jerk (shock degree) and the acceleration of the unmanned ground washing machine are relatively large when the pivot steering is started, and the control precision is relatively low near the target course.

Disclosure of Invention

The invention aims to provide a vehicle pivot steering control method, an automatic driving control system and a control device aiming at the technical defects in the prior art.

In a first aspect of the present invention, a method for controlling pivot steering of a vehicle is provided, including:

determining the rotation direction of the pivot steering of the vehicle and the waypoint track of the front wheels of the vehicle, wherein the waypoint track comprises waypoint speed information;

adjusting the gear of the vehicle and the initial angle of the front wheel of the vehicle according to the rotation direction;

determining a desired acceleration of the front wheels of the vehicle from the waypoint trajectory, the speed and the acceleration of the front wheels of the vehicle;

determining an output torque of a front wheel of the vehicle based on a speed of the front wheel and a desired acceleration;

and controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque.

In a second aspect of the present invention, an automatic driving control system is provided, which includes a planning decision module, a transverse control module and a longitudinal control module;

the planning decision module is used for determining the rotation direction and the waypoint track of the front wheels of the vehicle when the need of pivot steering is determined, and sending pivot steering indication information to the longitudinal control module and the transverse control module, wherein the waypoint track comprises waypoint speed information;

the transverse control module is used for adjusting the initial angle of the front wheels of the vehicle when the pivot steering indication information is received;

the longitudinal control module is used for adjusting the gear of the vehicle according to the rotating direction when the pivot steering indication information is received and the transverse control module finishes adjusting the initial angle of the front wheels of the vehicle; determining a desired acceleration of the front wheels of the vehicle from the waypoint trajectory, the speed and the acceleration of the front wheels of the vehicle; determining an output torque of a front wheel of the vehicle based on a speed of the front wheel and a desired acceleration; and controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque.

In a third aspect of the invention, there is provided a control device comprising at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the vehicle pivot steering control method.

In a fourth aspect of the present invention, there is provided a computer-readable storage medium containing a program or instructions for implementing the method for controlling pivot steering of a vehicle according to the first aspect when the program or instructions are run on a computer.

In a fifth aspect of the present invention, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the vehicle pivot steering control method provided by the first aspect.

In a sixth aspect of the invention, there is provided a vehicle including the control apparatus provided in the third aspect.

According to the vehicle pivot steering control method provided by the invention, the planned waypoint track of the front wheel of the vehicle also comprises the speed information of each waypoint, so that the speed of the front wheel of the vehicle is required to be matched with the speed of the waypoint in the waypoint track in the process of controlling the front wheel of the vehicle to run along the waypoint position of the waypoint track, the speed of the front wheel of the vehicle is controllable in the whole pivot steering process, the starting and stopping processes of the vehicle are relatively stable, and the aim of accurately controlling the vehicle is fulfilled.

Drawings

Fig. 1 is a schematic structural diagram of an automatic driving control system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of determining a waypoint speed of a waypoint trajectory provided by the embodiment of the invention;

FIG. 3 is a flow chart of determining a desired acceleration of the front wheels of the vehicle provided by an embodiment of the present invention;

FIG. 4 is an illustration of an interaction flow chart of modules in the automatic driving system according to an embodiment of the present invention;

FIG. 5 is a flowchart of an in-place steering control method according to an embodiment of the present invention;

FIG. 6 is a second flowchart of a pivot steering control method according to an embodiment of the present invention;

fig. 7 is a third flowchart of an in-place steering control method according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the embodiment of the invention, the vehicle refers to an automatic driving vehicle, such as an Ackerman steering automatic driving floor cleaning vehicle, an automatic driving dust collecting vehicle, an automatic driving sweeper, an automatic driving logistics trolley and the like. The automatic driving vehicle comprises a navigation module, a fixed module position (such as a GPS module, a GNSS module and the like), a sensor module (such as a camera, a laser radar, a millimeter wave radar, a wheel speed meter and the like), a sensing module, a planning decision module, a control module, a serial bus (Canbus) module and the like. The sensor module collects the surrounding environment information of the vehicle; the sensing module determines the information of obstacles around the vehicle according to the information of the environment around the vehicle; the positioning module acquires vehicle speed, pose information and the like; the navigation module is used for carrying out global path planning and navigation on the automatic driving vehicle; a planning decision module determines a local waypoint trajectory of the autonomous vehicle; the control module controls the autonomous vehicle to travel along the local waypoint trajectory. An autonomous driving control system generally includes the aforementioned sensing module, a planning decision module, and a control module.

The ackermann steering automatic driving vehicle has an in-situ steering function, when the automatic driving vehicle needs in-situ steering, the automatic driving control system enters an in-situ steering mode, as shown in fig. 1, and comprises a planning decision module 1 and a control module 2, wherein the control module 2 comprises a transverse control module 21 and a longitudinal control module 22, and the connection relationship among the planning decision module 1, the transverse control module 21 and the longitudinal control module 22 is as shown in fig. 1.

The planning decision module 1 is configured to determine a rotation direction and a waypoint trajectory of a front wheel of the vehicle when it is determined that pivot steering is required, and send pivot steering indication information to the longitudinal control module and the transverse control module, where the waypoint trajectory includes waypoint speed information.

In some optional embodiments, in the embodiments of the present invention, the waypoint speed of the waypoint trajectory may be obtained by using a trapezoidal speed planning algorithm, for example, as shown in fig. 2, the start point of the waypoint trajectory is set to a relatively small speed value (for example, 0.1m/s), and the end point speed of the waypoint trajectory is set to 0; the speed information of the middle waypoint can be set according to the strategies of firstly accelerating, then uniformly speed and then decelerating. The lengths of the acceleration section, the constant speed section and the deceleration section need to be flexibly set according to the length of the waypoint track, and the method is not strictly limited.

The planning decision module 1 determines whether pivot steering is required, which may be implemented by any one of the following ways: for example, when the user inputs the pivot steering mode through the vehicle-mounted terminal, the pivot steering is determined to be needed; for example, when a pivot steering instruction is received from the cloud server, it may be determined that pivot steering is required; for example, it is also possible that the planning decision module 1 determines whether pivot steering is required according to the navigation action of the global path planned by the navigation module.

And the transverse control module 21 is configured to adjust an initial angle of a front wheel of the vehicle when the pivot steering indication information sent by the planning decision module 1 is received.

The longitudinal control module 22 is configured to, when the pivot steering indication information sent by the planning decision module 1 is received and the transverse control module 21 completes adjustment of the initial angle of the front wheels of the vehicle, adjust the gear of the vehicle according to the rotation direction; determining a desired acceleration of the front wheels of the vehicle from the waypoint trajectory, the speed and the acceleration of the front wheels of the vehicle; determining an output torque of a front wheel of the vehicle based on a speed of the front wheel and a desired acceleration; and controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque.

In an alternative embodiment, the longitudinal control module 22 adjusts the gear of the vehicle according to the rotation direction, specifically including: if the rotation direction is leftward, when the front wheel of the vehicle turns leftward to a first angle, the gear of the vehicle is adjusted to be a forward gear; and if the rotating direction is rightward, when the front wheel of the vehicle rotates to a first angle leftward, the gear of the vehicle is adjusted to be a reverse gear.

In another alternative embodiment, the longitudinal control module 22 adjusts the gear of the vehicle according to the rotation direction, specifically including: if the rotation direction is leftward, when the front wheel of the vehicle turns leftward to a first angle, the gear of the vehicle is adjusted to be a forward gear; and if the rotating direction is rightward, when the front wheel of the vehicle rotates to a second angle rightward, adjusting the gear of the vehicle to be a forward gear.

In the foregoing embodiment, the first angle may be 90 degrees or approximately 90 degrees. The second angle may be 90 degrees or approximately 90 degrees.

In a preferred embodiment, the longitudinal control module 22 determines the desired acceleration of the front wheel of the vehicle according to the waypoint trajectory, the speed of the front wheel of the vehicle (referring to the linear speed of the front wheel of the vehicle) and the acceleration, and specifically may be implemented by the following steps 301 to 304 as shown in fig. 3, wherein:

step 301, selecting a first waypoint closest to a front wheel of the vehicle from the waypoint track;

step 302, determining a pre-aiming distance according to the speed and the acceleration of the front wheel of the vehicle and a preset minimum pre-aiming distance;

step 303, intercepting the pre-aiming distance along the waypoint track by taking the first waypoint as a starting point to obtain a pre-aiming point;

and step 304, determining the expected acceleration of the front wheel of the vehicle according to the speed of the preview point, the speed and the acceleration of the front wheel of the vehicle.

In the step 301, the distance between each waypoint in the waypoint trajectory and the position point of the front wheel of the vehicle may be calculated, and the waypoint with the minimum distance is selected as the first waypoint; or, fitting a curve to the locus of the waypoints, projecting the position points of the front wheels of the vehicle onto the fitted curve to obtain projection points, and determining the projection points as the first waypoints.

In an alternative embodiment, in step 302, the pre-aiming distance is determined according to the speed and acceleration of the front wheel of the vehicle and the preset minimum pre-aiming distance, which can be calculated by the following formula (1):

preview_dis＝v_nosewheel*τ+0.5*a_nosewheeltau + d formula (1)

In the formula (1), preview_disFor the pre-aiming distance, v_nosewheelFor the speed of the front wheels of the vehicle, τ is a preset lag time, a_nosewheelD is the preset minimum pre-aiming distance.

In an optional embodiment, in step 304, a desired acceleration of the front wheel of the vehicle is determined according to the speed of the preview point, the speed and the acceleration of the front wheel of the vehicle, which can be specifically calculated by the following formula (2):

in the formula (2), a_desiredFor desired acceleration of the front wheels of the vehicle, K_pFor a preset proportionality coefficient, K_iFor preset integral coefficient, e (k) v_p-v_nosewheelVp is the velocity of the preview point, v_nosewheelIs the speed of the front wheels of the vehicle,is the sum of k histories e (k).

In some alternative embodiments, the longitudinal control module 22 determines the output torque of the front wheels of the vehicle based on the speed and the desired acceleration of the front wheels of the vehicle, including: and determining output torque corresponding to the speed and the expected acceleration of the front wheels of the vehicle from the preset corresponding relation among the speed, the expected acceleration and the output torsion of the front wheels of the vehicle.

In one particular example, the correspondence between the speed of the front wheels of the vehicle, the desired acceleration and the output torsion is pre-processed in the following way:

firstly, selecting a test road, controlling an unmanned vehicle to adjust the initial angle of the front wheels of the vehicle to be 90 degrees leftwards, and controlling an automatic vehicle to run along the track of the waypoints of the front wheels of the vehicle after adjusting the gear;

secondly, recording a MAP graph of the speed of front wheels of the vehicle, the acceleration of the front wheels of the vehicle and the output torque in the process that the automatic driving vehicle runs along the road point track;

then, the acceleration of the front wheel of the vehicle at different speeds of the front wheel of the vehicle is tested under the torque of a fixed step length, the output torque is completed, and a two-dimensional table is drawn as shown in table 1 (the specific parameter values in table 1 are only examples and are not limited):

TABLE 1

Finally, the two-dimensional table of table 1 is converted into a two-dimensional table of drive torque versus vehicle front wheel speed and desired acceleration using matlab, as shown in table 2 (the specific values of the parameters in table 2 are merely examples and are not limiting):

TABLE 2

Of course, in some other alternative embodiments, instead of creating a two-dimensional table, a graph between the speed of the front wheels of the vehicle and the desired acceleration, output torque, may be created according to the foregoing steps.

The expected output torque is obtained by looking up the table 2 through a method of performing two-dimensional linear interpolation on the speed of the front wheels and the acceleration of the expected wheels, so that the speed control in the pivot steering mode is realized.

In an alternative embodiment, the longitudinal control module 22 determines the output torque corresponding to the speed and the desired acceleration of the front wheel of the vehicle from the preset corresponding relationship among the speed, the desired acceleration and the output torque of the front wheel of the vehicle, and specifically includes: and searching for the expected output torque corresponding to the speed and the expected acceleration of the front wheels of the vehicle from the corresponding relation by adopting a two-dimensional linear interpolation algorithm according to the speed and the expected acceleration of the front wheels of the vehicle.

In some preferred embodiments, the longitudinal control module 22 is further configured to, during the process of controlling the vehicle front wheels to rotate along the waypoint trajectory according to the output torque, determine whether the vehicle front wheels rotate to an end point of the waypoint trajectory, and if so, send a turn-back instruction to the lateral control module 21; the lateral control module 21 is further configured to control the front wheels of the vehicle to turn back to a preset third angle upon receiving a turn-back instruction.

In some alternative embodiments, the third angle may be 0 degrees or approximately 0 degrees.

In some alternative embodiments, the longitudinal control module 22 is further configured to determine that pivot steering has failed if there is an obstacle scram before determining that the front wheels of the vehicle are turned to the end of the waypoint trajectory. For example, in one embodiment, when the planning decision module 1 determines that an obstacle output scram command is present ahead of the autonomous vehicle, the longitudinal control module 22 determines that an obstacle scram is present and determines that pivot steering fails.

In some optional embodiments, the longitudinal control module 22 is further configured to determine that the pivot steering fails if the eps is determined to fail during the process that the lateral control module 21 controls the front wheels of the vehicle to turn back to the preset third angle. For example, in one embodiment, after sending the turn back instruction to the lateral control module 21, the longitudinal control module 22 continuously detects the eps angle value through the Canbus, determines whether the front wheels of the vehicle turn back to the third angle according to the eps angle value, and if so, determines that the pivot steering is successful; if the pivot steering is determined to fail when the eps is judged to have a fault according to the eps angle value, for example, the read front wheel angle value obviously does not belong to the normal angle range, or the angle value of the front wheel of the vehicle, which is read for a long time, is kept unchanged and is not the third angle, and the like.

In some preferred embodiments, the longitudinal control module 22, upon determining that the pivot steering is successful, sends a message to the planning decision module 1 indicating that the pivot steering is successful; the longitudinal control module 22, upon determining a pivot steering failure, sends a message to the planning decision module 1 indicating a pivot steering failure.

In some optional embodiments, the longitudinal control module 21 determines whether the front wheel of the vehicle rotates to the end of the waypoint trajectory, specifically including: selecting a second waypoint closest to the front wheels of the vehicle from the waypoint track; calculating the distance between the second waypoint and the endpoint of the waypoint track; and if the distance is smaller than a preset distance threshold value, determining that the front wheel of the vehicle rotates to the end point of the waypoint track.

In a specific implementation, the longitudinal control module 22 implements matching of a second waypoint closest to the front wheels of the vehicle during control of the front wheels of the vehicle to travel along the waypoint trajectory, and calculates a distance between the second waypoint and an end point of the waypoint trajectory; judging whether the distance is smaller than a set distance threshold value, if so, determining that the front wheel of the vehicle reaches the end point, otherwise, determining that the front wheel of the vehicle does not reach the end point, and sending a false mark (namely, an indication that the front wheel does not rotate back to a third angle) to the transverse control module 21; upon determining that the vehicle front wheel has reached the end point, it is determined whether the speed of the vehicle front wheel is 0 or approximately 0, if not, a false flag is sent to the lateral control module 21 (i.e., no rotation back to the third angle), and if so, it indicates that the autonomous vehicle has been adjusted to a better target pose, and at this time, a true flag (i.e., an indication of rotation back to the third angle) is sent to the lateral control module 21.

In one embodiment, as shown in fig. 4, the longitudinal control module 22 and the lateral control module 21 in the control module 2 determine whether to enter the pivot steering mode according to the pivot steering flag sent by the planning decision module 1, and when the pivot steering flag is true, determine that the pivot steering mode needs to be entered. After entering the pivot steering mode, the transverse control module 21 continuously detects a front wheel angle restoration flag sent by the longitudinal control module, and when the front wheel angle restoration flag is false, the automatic driving vehicle does not complete pivot steering, and at the moment, the transverse control module 21 sends a control instruction to turn the front wheel angle by 90 degrees to the left; when the recovered front wheel angle flag is detected to be true, which indicates that the longitudinal control module 22 has controlled the front wheels of the vehicle to reach the end point of the waypoint trajectory and complete pivot steering, the lateral control module 21 sends a control instruction to recover the front wheel angle of the vehicle to 0 °.

When entering the pivot steering mode, the longitudinal control module firstly checks the eps angle analyzed by the serial bus (canbus) module, and if the angle of the front wheel of the vehicle does not reach 90 degrees or approximate 90 degrees leftwards, the longitudinal control module keeps the front wheel of the vehicle in a static state and waits for the front wheel of the vehicle to turn leftwards to be close to 90 degrees.

The longitudinal control module 22 detects a road direction sign sent by the planning decision module 1 when detecting that the angle of the front wheel of the vehicle turns to the left to be close to 90 degrees, and sets the gear of the automatic driving vehicle as a forward gear if the road direction sign indicates that the vehicle turns to the left (for example, the road direction sign is 2); if the road direction flag indicates a turn to the right (e.g., road direction flag is 3), the gear of the autonomous vehicle is set to reverse.

The longitudinal control module 22 continuously judges whether the front wheels of the vehicle reach the end point of the waypoint track or not in the process of controlling the automatic driving vehicle to run along the waypoint track; if so, determining whether the speed of the front wheel of the vehicle is 0, if so, sending a recovered front wheel angle flag to the lateral control module 21 as true, otherwise, sending the recovered front wheel angle flag as false.

After the longitudinal control module 22 sends the flag indicating that the angle of the recovered front wheel is true to the transverse control module 21, continuously detecting the eps angle of the front wheel of the vehicle, judging whether the angle of the front wheel is recovered to 0 degree, and if so, feeding back the pivot steering success flag to the planning decision module 1; if not, judging whether an eps fault exists or not, if the eps fault exists, feeding back an in-situ steering failure mark to the planning decision module 1, and if the eps fault does not exist, feeding back the in-situ steering mark to the planning decision module 1.

Example two

An embodiment of the present invention provides a vehicle pivot steering control method, as shown in fig. 5, the method includes:

step 501, determining the rotation direction of the pivot steering of the vehicle and the waypoint track of the front wheels of the vehicle, wherein the waypoint track comprises waypoint speed information;

502, adjusting the gear of the vehicle and the initial angle of the front wheel of the vehicle according to the rotation direction;

step 503, determining the expected acceleration of the front wheel of the vehicle according to the waypoint track, the speed and the acceleration of the front wheel of the vehicle;

step 504, determining output torque of the front wheels of the vehicle according to the speed and the expected acceleration of the front wheels of the vehicle;

and 505, controlling the front wheels of the vehicle to rotate along the waypoint tracks according to the output torque.

In some optional embodiments, the foregoing step 502 may be specifically implemented by: if the rotation direction is leftward, adjusting the gear of the vehicle to be a forward gear and adjusting the initial angle of the front wheel of the vehicle to be a preset first angle leftward; and if the rotation direction is rightward, adjusting the gear of the vehicle to be reverse gear and adjusting the initial angle of the front wheel of the vehicle to be leftward to a preset first angle.

In some other optional embodiments, the foregoing step 502 may be specifically implemented by:

if the rotation direction is leftward, adjusting the gear of the vehicle to be a forward gear and adjusting the initial angle of the front wheel of the vehicle to be a preset first angle leftward; and if the rotating direction is rightward, adjusting the gear of the vehicle to be a forward gear and adjusting the initial angle of the front wheel of the vehicle to be a preset second angle rightward.

In some optional embodiments, the foregoing step 503 may be specifically implemented by: selecting a first waypoint closest to the front wheels of the vehicle from the waypoint track; determining a pre-aiming distance according to the speed and the acceleration of the front wheel of the vehicle and a preset minimum pre-aiming distance; intercepting the pre-aiming distance along the waypoint track by taking the first waypoint as a starting point to obtain a pre-aiming point; and determining the expected acceleration of the front wheel of the vehicle according to the speed of the aiming point, the speed and the acceleration of the front wheel of the vehicle. Referring specifically to the flow shown in fig. 3, for example, the pre-aiming distance may be calculated according to formula (1) in the first embodiment, and the desired acceleration of the front wheel of the vehicle may be calculated according to formula (2) in the first embodiment. And will not be described in detail herein.

In some alternative embodiments, the foregoing step 504 may be implemented as follows: and determining output torque corresponding to the speed and the expected acceleration of the front wheels of the vehicle from the preset corresponding relation among the speed, the expected acceleration and the output torsion of the front wheels of the vehicle. For example, a two-dimensional linear interpolation algorithm is employed to find a desired output torque corresponding to the speed and desired acceleration of the front wheels of the vehicle from the correspondence relationship, based on the speed and desired acceleration of the front wheels of the vehicle. For specific implementation, reference may be made to the description of related contents in the first embodiment, which is not described herein again.

In some preferred schemes, in step 505, in the process of controlling the front wheels of the vehicle to rotate along the waypoint locus according to the output torque, the method further includes step 505A, as shown in fig. 6, wherein:

and 505A, determining whether the front wheel of the vehicle rotates to the end point of the waypoint track, and if so, controlling the front wheel of the vehicle to rotate back to a preset third angle.

In some optional embodiments, in the foregoing step 505A, determining whether the front wheel of the vehicle rotates to the end of the waypoint trajectory specifically includes: selecting a second waypoint closest to the front wheels of the vehicle from the waypoint track; calculating the distance between the second waypoint and the endpoint of the waypoint track; and if the distance is smaller than a preset distance threshold value, determining that the front wheel of the vehicle rotates to the end point of the waypoint track.

In some preferred schemes, step 505 of the aforementioned method flow may further include the following step 505B and/or step 505C, as shown in fig. 7, including steps 505B and 505C, where:

and 505B, before the front wheels of the vehicle are determined to rotate to the end point of the waypoint track, if an obstacle suddenly stops, determining that pivot steering fails. Further, in step 505B, a pivot steering failure notification message may also be sent.

And 505C, in the process that the transverse control module controls the front wheels of the vehicle to rotate back to the preset third angle, if the eps is determined to be in fault, determining that the pivot steering fails. Further, in step 505C, a pivot steering failure notification message may also be sent.

EXAMPLE III

The third embodiment of the invention provides control equipment, which comprises at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executable by the at least one processor to enable the at least one processor to perform any one of the vehicle pivot steering control methods provided in the second embodiment.

Example four

A fourth embodiment of the present invention provides a computer-readable storage medium, which includes a program or an instruction, and when the program or the instruction runs on a computer, the method for controlling pivot steering of a vehicle according to the second embodiment is implemented.

EXAMPLE five

Fifth, an embodiment of the present invention provides a computer program product including instructions, which, when running on a computer, causes the computer to execute any one of the methods for controlling a pivot steering of a vehicle as provided in the second embodiment.

EXAMPLE six

The sixth embodiment of the invention provides a vehicle which comprises the control device provided by the third embodiment. The vehicle may be an autonomous vehicle, such as an autonomous vacuum cleaner, floor cleaner, sweeper, logistics vehicle, passenger vehicle, etc., and the specific type of vehicle is not limited in this application.

According to the vehicle pivot steering control method provided by the invention, the planned waypoint track of the front wheel of the vehicle also comprises the speed information of each waypoint, so that the front wheel of the vehicle is controlled to not only run along the waypoint position of the waypoint track but also be matched with the speed of the waypoint, the speed of the front wheel of the vehicle in the whole pivot steering process is controllable, the starting and stopping processes of the vehicle are relatively stable, and the aim of accurately controlling the vehicle is fulfilled.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.