Control Method of Vehicle, Automated Guided Vehicle and Computer-Readable Storage Medium

Abstract

The present invention discloses a control method for a vehicle. The control method includes: S101: determining a Bezier curve for the vehicle according to control points to connect a preset curve, where the preset curve and the Bezier curve form a trajectory curve of the vehicle; S102: obtaining a point with the maximum curvature of the Bezier curve; S103: segmenting the Bezier curve according to the point with the maximum curvature; S104: combining the segments of the preset curve and the Bezier curve into multiple blocks according to preset conditions; and S105: planning connection speeds between the respective blocks based on the multiple combined blocks.

Description

Technical Field

[0001] The present disclosure generally relates to the field of vehicle control, and more particularly to a control method for a vehicle, an automated guided vehicle, and a computer-readable storage medium. Background Art

[0002] With the development of factory production automation and logistics automation, traditional production and logistics transportation methods are evolving towards automation and intelligence. Flexible Manufacture System (FMS) and Stereoscopic Warehouse (SW) are increasingly widely used in production. As a cargo handling and transportation system, Automated Guided Vehicle System (AGVS) can meet the requirements of flexible manufacturing systems and stereoscopic warehouses, and is one of the most critical components of the entire logistics and production automation.

[0003] There are some trajectory planning and speed planning methods based on smooth transition of Bezier curves. Such methods are applied to the field of UAV navigation technology, and the main implementation logic is as follows: input waypoints, maximum speed, maximum acceleration, maximum jerk, and maximum allowable waypoint error in three-dimensional space; optimize the problem of the length of the straight flight segment and the maximum allowable trajectory smooth transition parameter; use a complete binary tree data structure and dynamic constraints to plan the speed of the curve segment; plan the speed of the straight segment according to the curve segment speed planning; perform real-time interpolation on the entire flight trajectory to obtain the reference flight trajectory. However, this method does not consider the impact of the curvature change of the Bezier curve on the running smoothness, nor does it fuse multiple trajectories that meet the motion characteristics in advance to improve efficiency.

[0004] The content in the background art section is only the technology known to the applicant, and does not necessarily represent the prior art in this field. Summary of the Invention

[0005] In view of at least one defect of the prior art, the present invention provides a control method for a vehicle, and the control method includes:

[0006] S101: Determine a Bezier curve for the vehicle according to control points to connect a preset curve, and the preset curve and the Bezier curve form a trajectory curve of the vehicle;

[0007] S102: Obtain the curvature extreme points of the Bezier curve;

[0008] S103: Segment the Bezier curve according to the curvature maximum points;

[0009] S104: Merge the segments of the preset curve and the Bezier curve into multiple blocks according to preset conditions; and

[0010] S105: Plan the connection speed between each block based on the merged multiple blocks.

[0011] According to one aspect of the present invention, the preset conditions include: if the two segments of the curve on both sides of the connection point between the preset curve and the Bezier curve satisfy the following relationship, or the two segments of the curve on both sides of the maximum curvature point satisfy the following relationship, then merge the two segments of the curve into one block:

[0012] The maximum speeds, maximum accelerations, and maximum jerk of the two segments of the curve are respectively the same; and

[0013] The speed at the connection point is equal to the maximum speed of the two end curves.

[0014] According to one aspect of the present invention, the step S105 includes: correcting the connection speed between each block by a look-ahead or look-back method.

[0015] According to one aspect of the present invention, the control method further includes: for each block, using an S-shaped interpolation algorithm to plan the corresponding expected positions, expected angles, expected linear velocities, expected linear accelerations, expected angular velocities, and expected angular accelerations at each sampling moment.

[0016] According to one aspect of the present invention, the control method further includes:

[0017] Select interpolation points according to the S-shaped interpolation algorithm;

[0018] Through linear mapping, obtain the expected values of the motion parameters corresponding to the interpolation points, where the motion parameters include position, angle, linear velocity, linear acceleration, angular velocity, and angular acceleration;

[0019] According to the expected values and the actual values of the motion parameters, perform Pid adjustment to control the vehicle.

[0020] According to one aspect of the present invention, the control method further includes:

[0021] Judge whether the Bezier curve and the preset curve can perform continuous movement, where when the angle between the first derivative vector directions of the Bezier curve and the preset curve at the connection point is less than the angle threshold, continuous movement can be performed; otherwise, continuous movement cannot be performed;

[0022] When continuous movement can be performed, control the vehicle to pass through the connection point without stopping; otherwise, reduce the speed of the vehicle to zero at the connection point, adjust the direction of the vehicle in place, and then restart.

[0023] According to one aspect of the present invention, the control method further includes:

[0024] When receiving a new motion path instruction, maintaining the current motion state and performing a first delay compensation;

[0025] Judging whether the acceleration of the vehicle is zero;

[0026] When the acceleration of the vehicle is not zero, controlling the acceleration of the vehicle to gradually decrease to zero, and then re-performing the above planning and S-shaped interpolation for the remaining segments.

[0027] According to one aspect of the present invention, a speed limit is set for the connection points between the Bezier curve and the preset curve, or between adjacent Bezier curves, wherein when the included angle between the first derivative vector directions is less than the angle threshold, the speed limit is the smaller of the maximum speeds of the two curves; when the included angle between the first derivative vector directions is greater than the angle threshold, the speed limit is zero.

[0028] The present invention also relates to an automated guided vehicle, including:

[0029] A vehicle body;

[0030] A wheel set mounted on the vehicle body;

[0031] A controller, which is coupled to the wheel set and configured to execute the control method as described above and control the movement of the wheel set.

[0032] The present invention also relates to a computer-readable storage medium, including computer-executable instructions stored thereon, and the executable instructions implement the control method as described above when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Shows a control method for a vehicle according to an embodiment of the present invention;

[0034] Figure 2A And 2B Respectively show examples of a quartic Bezier curve and a quintic Bezier curve;

[0035] Figure 3A And 3B Shows a schematic diagram of the merging of motion segments;

[0036] Figure 4 Shows a schematic diagram of planning the connection speed between each block segment through look-ahead and look-back techniques;

[0037] Figure 5 Shows a schematic diagram of obtaining ideal motion parameters through linear mapping;

[0038] Figure 6A and 6B respectively show schematic diagrams that meet the continuous motion condition and do not meet the continuous motion condition. Detailed implementation manners

[0039] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0041] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection: it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the contact between the first and second features through additional features therebetween rather than direct contact. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0043] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0045] Figure 1 A control method 100 of a vehicle according to an embodiment of the present invention is shown. The vehicle includes, for example, an automatic guided vehicle (AGV), a forklift used in a warehouse, etc., and will be described in detail below with reference to the accompanying drawings.

[0046] In step S101: According to the control points, a Bezier curve for the vehicle is determined to connect to a preset curve, and the preset curve and the Bezier curve form the trajectory curve of the vehicle.

[0047] The Bezier curve is a parametric curve based on approximation and can be used in the control of mobile robots. A first-order Bezier curve has the following expression:

[0048]

[0049] where is the node value, is the control point of the Bezier curve. By specifying the control points of the Bezier curve, the general trend of the curve can be controlled. The Bezier curve starts from the first control point and ends at the last control point, that is:

[0050]

[0051] The first derivative vector directions of the Bezier curve at the two end points are along the first side and the last side of the characteristic polygon respectively, that is:

[0052]

[0053] The second derivative vectors of the Bezier curve at the two end points are only related to the front and back 3 control points, and their relationship is as follows:

[0054]

[0055] For example, given two preset curves with a gap between them, the end points of the two preset curves can be used as the first control point and the last control point of the Bezier curve. On this basis, more control points can be set as needed to determine the Bezier curve connecting the preset curves.

[0056] Figure 2A and 2B respectively show examples of a quartic Bezier curve and a quintic Bezier curve. As Figure 2A shown, the preset curves to be connected are A - A' and C - C' (straight lines in the figure), and their end points A and C form the control points of the Bezier curve. In addition, the intersection point B of the extension lines of the tangents of the preset curves A - A' and C - C' at the end points A and C respectively is obtained as the third control point. Therefore, in Figure 2A 3 control points are obtained: A, B, C, where D and E are the mid - points of the straight lines AB and BC respectively.

[0057] In Figure 2B the preset curves to be connected are A - A' and D - D' (straight lines in the figure), and their end points A and D form the control points of the Bezier curve. In addition, control points B and C are obtained. The control point B can be selected on the extension line of the straight line A - A' (or on the tangent of the curve A - A' at point A), and the control point C can be selected on the extension line of the straight line D - D' (or on the tangent of the curve D - D' at point D). Preferably, the lengths of AB and CD can be within a range of 1 code pitch (for example, 1.2 m). Of course, the control points B and C can also be selected in other ways, and the present invention is not limited to the specific way of selecting control points. Therefore, in Figure 2B 4 control points are obtained: A, B, C, D, where E and F are the mid - points of AB and CD respectively. According to the end - point properties of the Bezier curve mentioned above, choosing points A, E, B to be collinear and points C, F, D to be collinear is to ensure that the curvature of the Bezier curve at the end points is 0 and prevent acceleration jumps in the radial direction.

[0058] After determining the control points, the Bezier curve can be determined according to the above method.

[0059] Figure 2A and 2B Figure 6 shows connecting two preset curves through a Bezier curve. The present invention is not limited thereto. Two Bezier curves can also be used to connect two preset curves. Alternatively, one or both of the preset curves can also be Bezier curves. All of these are within the protection scope of the present invention.

[0060] In step S102: Obtain the points of maximum curvature of the Bezier curve.

[0061] For each Bezier curve obtained in step S101, calculate its points of maximum curvature. The specific method is as follows. Divide the node interval [0 - 1] of the Bezier curve into given discrete numbers to obtain node increments , starting from , sample points on the Bezier curve one by one according to the recurrence formula and calculate the curvature of the sampled points according to the following formula:

[0062]

[0063] where , respectively represent the first-order and second-order derivative vectors of the Bezier curve at node . is the corresponding curvature value.

[0064] Due to the local nature of the extreme value, the curvature of the maximum (minimum) value point must be greater (less) than the curvature of other points on both sides of this point within a certain local range. Let be a point of maximum curvature on the Bezier curve, be the corresponding curvature value, and be two points on the curve that are apart from this point in terms of parameters respectively. Then, according to the local nature of the maximum value, there is:

[0065]

[0066] Therefore, the points of maximum curvature of the Bezier curve can be obtained according to the curvature of the sampled points calculated one by one according to the above formula.

[0067] In step S103: Segment the Bezier curve according to the points of maximum curvature. Use the points of maximum curvature as the demarcation points to segment each Bezier curve. If there are multiple points of maximum curvature, the Bezier curve will be divided into multiple segments.

[0068] In step S104: The segments of the preset curve and the Bezier curve are merged into multiple blocks according to preset conditions. A specific embodiment is described below.

[0069] For each preset curve, it can participate in the merging as a single segment, or the curvature maximum points of the preset curve can be found in the manner of steps S102 and S103, and the curvature maximum points are used as demarcation points (or connection points) for segmentation (especially when the preset curve itself is a Bezier curve), and then the multiple segments obtained by decomposition are used to participate in the merging. These are all within the scope of the present invention and will not be elaborated here.

[0070] According to a preferred embodiment of the present invention, the speed at the curvature extreme points of the Bezier curve can be limited. When the curvature of the Bezier curve is relatively large, it means that the planned speed needs to be reduced to reduce the change in its rotational angular velocity, otherwise there will be skidding and excessive lateral deviation, resulting in the vehicle stalling and running off course. Here, the reference circle speed , reference circle radius are set. The reference circle radius is a virtual concept, which refers to a given value of the curvature radius. When the curvature radius of a point on the curve is the reference circle radius, the maximum allowable speed is the reference circle speed. For example, it is stipulated that when the curvature radius of a point on the curve is 1 meter, its maximum speed is 0.5 m / s. Here, the curvature radius of 1 and the maximum speed of 0.5 are the reference circle radius and the reference circle speed. At this time, the maximum allowable speed when the curvature radius is 2 can be calculated by the following formula. Given the circle speed and reference circle radius , according to the acceleration formula, the restricted speed at the curvature extreme point is:

[0071]

[0072] Where is the curvature of the curvature extreme point of the Bezier, is the corresponding restricted speed at the curvature maximum point. It can be seen that as the curvature increases, the corresponding restricted speed at the curvature maximum point also decreases. However, in this case, when the curvature value is too large, it will cause the rotational speed directions of the left and right wheels to be inconsistent, as follows:

[0073]

[0074] Where respectively represent the right wheel speed, left wheel speed, wheelbase, linear speed, and angular velocity value. Here, it is set that the vehicle deflects to the left, then there is . If the rotational speed directions of the left and right wheels are to be different, then there is , and we get:

[0075]

[0076] And here , substituting it in, we can get , because the curvature value at the extreme point of curvature is constant, so it is inevitable that the directions of the left and right wheels are different, but the rotational angular velocity can be reduced , and then the corresponding left and right wheel speeds are reduced, reducing this speed change. When , the following speed limit strategy is adopted:

[0077]

[0078] Here represents the critical reference curvature value, represents the reference speed when the given critical reference curvature is given, is the curvature value on the current curve. The critical reference curvature value and the reference speed can be obtained according to actual debugging, and are used to control the rotational angular velocity of the vehicle to be reduced as much as possible when the curvature is too large.

[0079] After the Bezier curve is segmented, the segmented Bezier curve together with the preset curve constitutes multiple segments, or motion segments, and the vehicle needs to transition between different motion segments. Preferably, the speed limits between different motion segments can be calculated.

[0080] Between different motion segments, there are several modes including: straight line connecting to straight line, straight line connecting to Bezier curve, and Bezier curve connecting to Bezier curve. Here, the included angle of the first-order derivative vectors at the connection end point of two segments (motion segments) is set as , then the speed limit constraint is as follows:

[0081]

[0082] Wherein respectively represent the maximum speeds of the first motion segment and the second motion segment, is the connection speed of the two motion segments. Therefore, when the absolute value of the included angle of their first-order derivative vectors is not greater than 2 o , the maximum value of the connection speed of the two motion segments is the smaller one of the maximum speeds of the first motion segment and the second motion segment; when the absolute value of the included angle of their first-order derivative vectors is greater than 2 o , the connection speed should be 0, that is, the vehicle should first stop at the end point of the first motion segment, adjust its angular orientation, and then proceed to the second motion segment.

[0083] For a B-spline curve, it can be segmented according to the points of maximum curvature. For example, if a certain B-spline curve has two points of maximum curvature, it is split into three segments. A straight line does not need to be split. The above-mentioned segmentation is performed according to the points of extreme curvature, and the limiting speeds at the points of maximum curvature of each segment are obtained. , and at this time, according to the motion parameters of each segment (including the segments of the B-spline curve, the preset curve, or the segments of the preset curve) (including the maximum speed , the maximum acceleration , the maximum jerk , the connection speed ), it is determined whether the segments can be merged, and then the segments that can be merged are taken as a block. Among them, the maximum speed of each segment can come from the host computer or the control device. According to one embodiment, after the host computer determines the B-spline curve, it can directly allocate a maximum speed. After determining the points of maximum curvature of the B-spline curve and performing segmentation, the maximum speed also applies to each segment. The same is true for the maximum acceleration and the maximum jerk, which will not be elaborated here. According to a preferred embodiment of the present invention, the judgment logic for whether merging can be performed is as follows:

[0084] The motion parameters of two segments are the same, that is: ;

[0085] The limiting speed at the connection point or the point of maximum curvature is greater than or equal to the maximum speeds of the two segments, that is: ;

[0086] If the above two conditions are met, the two segments can be merged into one block, and so on, traversing all adjacent segments, and merging the segments that satisfy the above relationship.

[0087] As Figure 3A shows, there are 4 motion segments , which are a straight line, a 5th-degree B-spline curve, a 5th-degree B-spline curve, and a straight line, are the 2 points of extreme curvature of the segment (firstly split), are the 2 points of extreme curvature of the segment. Here, it is assumed that the motion parameters of the 4 motion segments are the same, and the limiting speeds obtained from the points of extreme curvature are lower than the maximum speeds of each segment. Then, through the above merging rules, the following merged blocks can be obtained: . Among them, block includes Figure 3A the trajectory A-P1 in ; block Figure 3A includes the trajectory P1-P2 in Figure 3A ; block including Figure 3A the trajectory P3 - P4 in; block including Figure 3A the trajectory P4 - H in; block including Figure 3A the trajectory H - I in.

[0088] In step S105: Based on the merged multiple blocks, correct the connection speed between each block.

[0089] For the merged blocks, it is necessary to re - update the connection speed between each block segment. According to a preferred embodiment of the present invention, look - ahead and look - back techniques can be used for processing, as Figure 4 shown, and the specific description is as follows.

[0090] The look - ahead logic is: First, start from the starting block at the starting speed (corresponding to the origin O in Figure 4 ), and under the given motion parameters, accelerate with the maximum ability to obtain the maximum speed at the end , where the connection segment limit speed , and the corrected end connection speed is: ;

[0091] After that, use the corrected connection speed as the starting speed of the next block, and continue to traverse in this way until the end of the last block.

[0092] The look - back logic is: Start from the end speed (creeping speed) of the last block, and perform reverse acceleration with the maximum ability to obtain the starting speed of this block. Combine the connection speed obtained during look - ahead to reverse - correct the final connection speed between each segment. That is:

[0093]

[0094] According to a preferred embodiment of the present invention, the control method further includes: For each block, use the S - type interpolation algorithm to plan the corresponding desired position, desired angle, desired linear velocity, desired linear acceleration, desired angular velocity, and desired angular acceleration at each sampling moment. The most important feature of S - type acceleration and deceleration is that the shape of the speed of this algorithm is similar to the letter S. The speed curve of S - shaped acceleration and deceleration is smooth and the acceleration is continuous, so as to be able to reduce the impact during the control process and make the interpolation process flexible. Here, for each block, straighten the discrete small line segments in each block, and then according to the given motion parameters (starting speed , termination speed , maximum speed , maximum acceleration Jerk ) to calculate the motion process of each segment.

[0095] According to a preferred embodiment of the present invention, the control method further includes:

[0096] Select interpolation points, for example, obtain interpolation points on discrete small line segments according to S-shaped (velocity S-shaped, corresponding acceleration trapezoid) planning;

[0097] Through linear mapping, obtain the expected values of motion parameters corresponding to the interpolation points, where the motion parameters include position, angle, linear velocity, linear acceleration, angular velocity, and angular acceleration;

[0098] According to the expected values and the actual values of the motion parameters, perform Pid adjustment to control the vehicle.

[0099] As Figure 5 shown, the thick black curve represents the actual Bezier curve, the black straight line segments represent the small line segments after discretizing the Bezier curve, the Bezier node value corresponding to point B is , the Bezier node value corresponding to point C is . When the interpolation point is at the black thin straight line D on the BC segment, it is known that the length of BD is , the length of BC is . It is necessary to find the node value corresponding to point D. Here, a linear mapping method is used for processing, that is:

[0100]

[0101] Substitute the node U value obtained from point D into the Bezier curve formula to obtain the corresponding two-dimensional expected position .

[0102] According to a preferred embodiment of the present invention, the control method further includes:

[0103] Judge whether the Bezier curve and the preset curve can perform continuous motion. When the angle between the first derivative vector directions of the Bezier curve and the preset curve at the connection point is less than the angle threshold, continuous motion can be performed; otherwise, continuous motion cannot be performed;

[0104] When continuous motion can be performed, control the vehicle to pass through the connection point without stopping; otherwise, reduce the speed of the vehicle to zero at the connection point, adjust the direction of the vehicle in place, and then restart.

[0105] The meaning of continuity is: smoothly connect the previous motion instruction. When entering a new motion path, the Agv does not need to decelerate to 0 to achieve it.

[0106] The first derivative vector directions of the two motion trajectories at the connection are respectively , and according to the dot product formula, the included angle can be described as:

[0107]

[0108] If it is considered that the continuous movement can be executed, then the continuous movement cannot be executed. When the Agv moves to the connection point of the two paths, the speed needs to be reduced to 0, and then rotated by an angle, and then the next movement is executed.

[0109] As Figure 6A shown, the current vehicle motion trajectory is a straight line, and the Bezier curve trajectory is sent during the Agv movement. Figure 6A The first derivative vector of the straight line AB at the end point B in is: , and the first derivative vector of the Bezier curve at the end point B is: . Since points A, B, and C are collinear, it can be known that Figure 6B are in the same direction, meeting the continuous movement condition; In , points A, B, and C are not collinear, and the included angle is

[0110] , then this does not meet the continuous movement condition. At this time, after the Agv stops walking the straight line AB, it rotates by an angle

[0111] and moves to the direction BC, and then moves along the Bezier trajectory.

[0112] Judge whether the acceleration of the vehicle is zero;

[0113] When the acceleration of the vehicle is not zero, control the acceleration of the vehicle to gradually decrease to zero, and then perform the S-shaped interpolation.

[0114] The present invention also relates to an automatic guided vehicle, including a vehicle body, a wheel set, and a controller, wherein the wheel set is installed on the vehicle body, and the controller is coupled to the wheel set and configured to execute the control method as described above and control the movement of the wheel set.

[0115] The present invention also relates to a computer-readable storage medium, including computer-executable instructions stored thereon, and the executable instructions implement the control method as described above when executed by a processor.

[0116] Embodiments of this invention propose a curvature speed limit strategy and a block fusion strategy to achieve smooth and high-speed movement of an automated guided vehicle.

[0117] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a vehicle, the control method comprising: S101: Determine a Bezier curve for the vehicle according to control points to connect a preset curve, and the preset curve and the Bezier curve form a trajectory curve of the vehicle; S102: Obtain the maximum curvature point of the Bezier curve; S103: Segment the Bezier curve according to the maximum curvature point; S104: Merge the segments of the preset curve and the Bezier curve into multiple blocks according to preset conditions, where the preset conditions include that the motion parameters of two segments of curves on both sides of the connection point between the preset curve and the Bezier curve or two segments of curves on both sides of the maximum curvature point are the same, and the limited speed at the connection point or the maximum curvature point is greater than or equal to the maximum speed of the two segments of curves; and S105: Plan the connection speed between each block based on the merged multiple blocks.

2. The control method according to claim 1, wherein the motion parameters include: The maximum speed, maximum acceleration, and maximum jerk, the preset conditions include: The maximum speed, the maximum acceleration, and the maximum jerk of the two segments of curves are respectively the same.

3. The control method according to claim 2, wherein the step S105 includes: Correct the connection speed between each block by a look-ahead or look-back method.

4. The control method according to any one of claims 1-3 further comprises: For each block, adopt an S-shaped interpolation algorithm to plan the corresponding desired position, desired angle, desired linear velocity, desired linear acceleration, desired angular velocity, and desired angular acceleration at each sampling moment.

5. The control method according to claim 4, further comprising: Select interpolation points according to the S-shaped interpolation algorithm; Obtain the expected values of the motion parameters corresponding to the interpolation points through linear mapping, where the motion parameters include position, angle, linear velocity, linear acceleration, angular velocity, and angular acceleration; Perform Pid adjustment according to the expected values and the actual values of the motion parameters to control the vehicle.

6. The control method according to any one of claims 1-3, further comprising: Judge whether the Bezier curve and the preset curve can perform continuous movement, where when the included angle between the first derivative vector directions of the Bezier curve and the preset curve at the connection point is less than an angle threshold, continuous movement can be performed; Otherwise, continuous movement cannot be performed; When continuous movement can be performed, control the vehicle to pass through the connection point without stopping; otherwise, reduce the speed of the vehicle to zero at the connection point, adjust the direction of the vehicle in place, and then restart.

7. The control method according to claim 4, further comprising: When receiving a new motion path instruction, maintain the current motion state and perform a first delay compensation; Judge whether the acceleration of the vehicle is zero; When the acceleration of the vehicle is not zero, control the acceleration of the vehicle to gradually decrease to zero, and then re-perform the above planning and S-shaped interpolation for the remaining segments.

8. The control method according to any one of claims 1-3 further includes: Set the speed limit at the connection point between the Bezier curve and the preset curve or between adjacent Bezier curves, where when the included angle between the first derivative vector directions is less than the angle threshold, the speed limit is the smaller one of the maximum speeds of the two curves; when the included angle between the first derivative vector directions is greater than the angle threshold, the speed limit is zero.

9. An automatic guided vehicle, comprising: A vehicle body; Wheel set, installed on the vehicle body; Controller, the controller is coupled to the wheel set and configured to execute the control method according to any one of claims 1-8, and control the movement of the wheel set.

10. A computer-readable storage medium, including computer-executable instructions stored thereon, the executable instructions implementing the control method according to any one of claims 1-8 when executed by a processor.

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