Master-slave cooperation space-time planning control method for group compaction operation

Abstract

The invention provides a group compaction operation-oriented master-slave cooperation space-time planning control method. The method comprises the following steps of 1, determining a construction region boundary and performing equal-area grid division; 2, a road roller starting path is generated through a third-order Bezier curve and curvature constraint, and each road roller generates a local path to the starting point of the target operation area according to the initial position of the road roller; 3, performing multi-machine path coordination based on space-time constraint, performing speed assignment on each point after each road roller completes local path planning from the current position to the starting point of the target area, and calculating expected time required by path completion; 4, a real-time state synchronization and safety protection mechanism is established, all the road rollers broadcast self position information at a fixed frequency in the operation process, the real-time distance between every two road rollers (i, j) is calculated, and the safety distance is set; and the collision between the two road rollers is avoided by judging the real-time distance and the safe distance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned driving, in particular to a master-slave cooperative space-time planning control method for group compaction operation. BACKGROUND

[0002] With the development of intelligent construction technology and the popularization and application of unmanned equipment, the automation and collaboration level of road compaction link has become a key factor restricting the quality and efficiency of unmanned construction. Traditional road roller operation usually relies on manual driving, and the compaction path and operation rhythm are determined by manual experience. This way is prone to problems such as path overlap, rolling omission and collision between devices in the multi-machine collaborative scene. Especially in large-area or complex-shaped construction areas, manual scheduling cannot accurately divide the work area, and it is difficult to realize efficient collaborative operation of multiple road rollers.

[0003] The existing multi-machine control technology of unmanned road roller mainly focuses on two categories: one is the cooperative control method based on preset path, which divides the construction area into fixed sub-regions by prior planning, and assigns paths to each road roller, but this method lacks adaptability and cannot dynamically adjust the task according to the real-time state; the other is the operation coordination method based on centralized scheduling, which plans the path and speed uniformly by the upper computer, but this method requires high communication delay and positioning accuracy, and lacks perfect collision avoidance and synchronization mechanism, making it difficult to run stably in dynamic working conditions. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a master-slave cooperative space-time planning control method for group compaction operation, which uniformly divides the work area by the master device, establishes a space-time constraint path planning mechanism, and combines a shared state safety protection mechanism module to realize safe, efficient and collision-free collaborative compaction of multiple road rollers in the same area.

[0005] To achieve the above purpose, the present application adopts the following technical scheme: a master-slave cooperative space-time planning control method for group compaction operation, comprising the following steps:

[0006] Step 1: determine the boundary of the construction area and perform equal-area grid division;

[0007] Step 2: generate the starting path of the road roller through a third-order Bezier curve and curvature constraint, and each road roller generates a local path from its initial position to the starting point of the target work area;

[0008] Step 3: coordinate the paths of multiple machines based on space-time constraints, and after each road roller completes the local path planning from the current position to the starting point of the target area, assign a speed value to each point and calculate the expected time required to complete the path;

[0009] Step 4: Establish real-time state synchronization and security protection mechanism, in the process of operation, all road rollers broadcast their own position information at a fixed frequency, calculate the real-time distance between each two road rollers (i, j) , set the safety distance ; avoid collision between two road rollers by judging the real-time distance and the safety distance .

[0010] In a preferred embodiment, step 1 includes: the main device takes points on the boundary through the RTK positioning system, obtains the boundary coordinate information of the rectangular construction area, establishes the reference coordinate system, and converts the received longitude and latitude into the Northeast coordinate system using the following formula:

[0011] ,

[0012]

[0013] Among them is the Northeast coordinate, E represents the eastward offset, N represents the northward offset, U represents the vertical offset, is the target point's geocentric coordinate, is the reference point's geocentric coordinate, is the coordinate difference value of the target point and the reference point in the geocentric coordinate system, R is the rotation matrix, which rotates the axis of the earth coordinate system to align with the Northeast direction of the reference point, is the accuracy of the reference point, unit is radian, is the dimension of the reference point, unit is radian.

[0014] Combine the number of road rollers M and the total area of the rectangular construction area Divide the rectangular construction area into N sub-regions along the X and Y axes of the Northeast coordinate system, where N is the same as M, and automatically calculate the theoretical area of single vehicle operation partition:

[0015]

[0016] When N is even, form two columns of N / 2 rows of block regions; when N is odd, form two columns of (N+1) / 2 block regions; the size of each sub-region is determined according to the length and width of the rectangular boundary according to the following formula:

[0017] , Among them represents rounding up;

[0018] The division result forms a set of rectangular grid regions R(a,b) :

[0019]

[0020] All areas are numbered in order from left to right and from top to bottom: , ,..., , ...

[0021] Then each sub-grid area is assigned to the corresponding road roller according to the road roller number, and the four vertex coordinates and boundary parameters of the area are issued to each vehicle.

[0022] In a preferred embodiment, step 2 includes planning an ideal path B(t) using a third-order Bezier curve, with the specific formula: where t is a normalized parameter, When t = 0, B(t) is located at the current initial position , i.e. the starting point of the curve, and when t = 1, B(t) is located at the starting point of the target work area , i.e. the end point of the curve; represents the current initial position of the road roller; represents the starting point of the target work area; represents an intermediate control point dynamically generated according to the initial orientation, represents an intermediate control point dynamically generated according to the target direction, used to control the curvature shape;

[0023] During planning, the maximum allowed curvature is set, and through iterative adjustment of the intermediate control point dynamically generated according to the initial orientation and the intermediate control point dynamically generated according to the target direction, the planning curvature is made to be less than or equal to the maximum allowed curvature:

[0024]

[0025] where represents the curvature of the curve at time t, max represents the maximum allowed curvature value.

[0026] The curvature formula of the third-order Bezier curve is:

[0027]

[0028] where and are the coordinate positions of the curve in a two-dimensional plane, and is the first order derivative of the coordinate position with respect to time t, and is the second order derivative of the coordinate position with respect to time t.

[0029] In a preferred embodiment, step 3 comprises: setting the time Δt , from point k to k+1 when the road roller travels on the interval i,k

[0030]

[0031] where di i,k is the path distance of the ith road roller on the path between the kth point and the k+1th point; vi i,k denotes the set speed of the ith road roller at the kth path point; vi+1 i,k+1 denotes the set speed of the ith road roller at the k+1th path point. denotes the average speed of the road roller when traveling on the interval , .

[0032] Then the expected arrival time of the ith road roller at the kth point is:

[0033] where, is the time when the road roller starts to perform the path at the initial moment;

[0034] The road roller passes through the path point corresponding to the occupation time interval is:

[0035]

[0036] where and are the time reserved for the road roller to enter and leave the path point.

[0037] In a preferred embodiment, step 3 further comprises: uploading the expected time to the host device, the host device performing space-time modeling of the path corresponding to the expected time of all road rollers, establishing the correspondence between the time window and the space grid, mapping the path point position to the grid set, finding all grid sets G that satisfy , and marking the grid that satisfies the condition and the time interval corresponding to the occupation, then marking the grid occupation at each time sampling point in the time interval is expressed as .

[0038] If there is any grid that satisfies in the same time interval,If there are at least two road rollers in the same time interval, it means that there is an overlap of occupation, and a time-space conflict occurs.

[0039] If a time-space conflict occurs, the expected time of each road roller to the starting point of the target area is used as the priority judgment basis. The longer the time spent, the lower the priority. For the road roller with low priority in the conflict, the speed is scaled by multiplying :

[0040]

[0041] where v i is the adjusted real-time target speed of the i-th road roller, and α is the speed scaling coefficient, which is between .

[0042] At this time, the speed profile is:

[0043] where is the path point coordinate of the i-th road roller, and the control instruction set of the road roller at the path point coordinate corresponding speed is formed.

[0044] Set = 0.5, the initial value is 1.0, the speed scaling value is reduced by 0.05 each time, and the time-space occupation is detected to determine whether there is an overlap, thereby resolving the conflict.

[0045] In a preferred embodiment, step 4 includes:

[0046] When , it is a normal state, and it is considered that there is no collision risk between the two road rollers, and each road roller maintains the original speed planning instruction for rolling operation;

[0047] When , it is a warning state, and the master device determines the relationship type of the two road rollers through the projection difference in the direction of the coordinate axis and the previously divided area, and sets the operation bandwidth For the front-rear relationship on the same operation band: if , it means that the two vehicles are in a front-rear relationship, and if , the is in front of the ; if , the is behind the ; for the left-right relationship of adjacent operation bands, if , it means that the two vehicles are in a left-right relationship, and if , the is on the left side of the ; if then on the right side of ;

[0048] When , it is a dangerous state, at which time the master device starts an emergency anti-collision mechanism and executes a multi-machine safety strategy.

[0049] In a preferred embodiment, when the two road rollers are in a pre-warning state in step 4, a priority is set:

[0050] If it is a front-rear relationship, i.e., the same road roller direction, then the rear roller is scaled in speed wherein = 0.5,

[0051] The initial value is 1.0, the speed scaling value is reduced by 0.05 each time, and the real-time distance between the two rollers is detected to determine whether it returns to a normal state, so as to release the pre-warning state.

[0052] If it is a left-right relationship, i.e., adjacent working zones are operated in parallel, then the right roller is instructed to scale in speed to maintain a lateral safety distance.

[0053] In a preferred embodiment, when the two road rollers are in a dangerous state in step 4, a priority is determined and a region is blocked: the master device first determines the "main vehicle" and the "avoidance vehicle" according to the working task priority, and temporarily establishes a local "safe exclusion zone" in the working area. For the main vehicle i and the avoidance vehicle j, assuming that the current coordinates are:

[0054]

[0055] A minimum bounding box AABB is constructed from two points:

[0056]

[0057]

[0058] An initial conflict box is obtained:

[0059]

[0060] The region is inflated outward, and the inflation distance is as follows:

[0061]

[0062] wherein is the maximum working speed of the road roller, is the response time;

[0063] Minkowski inflation operation is performed, and the inflated dangerous region is:

[0064]

[0065] Map the dangerous area to the grid, and for all grid sets G, if the center of the grid satisfies:

[0066]

[0067] Mark its grid state as "prohibited", that is, mark the occupation on the time window corresponding to the grid, if other road rollers plan the path through the "prohibited" grid, re-plan the path to avoid secondary risks.

[0068] In a preferred embodiment, when the two road rollers are in a dangerous state in step 4, an emergency stop command is immediately issued to the avoiding vehicle, and the speed planning of the current path segment of the vehicle is frozen to prevent the road roller from still driving according to the speed planning, that is:

[0069]

[0070] The master device detects the speed feedback value of the vehicle in real time in the subsequent period, and confirms that the emergency stop is completed when detecting that the actual speed is less than 0.05 m / s.

[0071] In a preferred embodiment, when the two road rollers are in a dangerous state in step 4, the system predicts the shortest stopping distance according to the master vehicle braking acceleration and the response time:

[0072]

[0073] If , the system sends a braking command to the master vehicle at the same time.

[0074] Compared with the prior art, the present application has the following beneficial effects:

[0075] (1) The work area allocation method based on equal-area grid division

[0076] After the master device obtains the boundary information of the rectangular construction area through RTK, the equal-area division is performed based on the number N of road rollers. The equal-area grid division algorithm is used to divide the construction area into N rectangular sub-areas to form a "bean curd block" type partition structure. Each sub-area corresponds to the working range of one road roller. This area division method converts the originally complex multi-machine cooperation problem into several single-machine path planning problems, thereby significantly simplifying the control complexity of the multi-machine system and ensuring the complete coverage and uniform distribution of the work area.

[0077] (2) Multi-machine path planning method based on space-time constraints

[0078] After the regional division is completed, each road roller generates a starting point path based on the construction area allocated by the master device through the current starting position and the starting point of the target area using a space-time constraint path planning algorithm. This algorithm introduces a "time window" constraint in the time dimension, discretizes the path into space-time nodes, uploads them to the master device, and the master device draws a space-time pre-occupancy table from the received space-time nodes. The purpose of this table is to detect conflicts in the starting path. The space-time pre-occupancy table is used to determine whether different road rollers occupy the same space at the same time. If a conflict is detected, the master device dynamically adjusts the priority based on the estimated time of the road roller reaching the target area. Road rollers with low priority are automatically delayed in entering the conflict area, and the path point speed is re-planned in a time offset manner to ensure collision-free execution of the global path.

[0079] (3) Collision risk prediction and safety control mechanism based on real-time state sharing

[0080] The present application proposes a multi-vehicle safety protection mechanism based on real-time state sharing. The global state is synchronized through high-speed broadcasting of road roller position, speed, and heading. The front and rear or left and right relationships of vehicles are identified based on regional and positional projection relationships. The system divides the state into three categories: normal, warning, and dangerous, based on safety distance. Differentiated deceleration is performed according to the relationship in the warning state. In the dangerous state, the system performs Minkowski expansion on the collision area based on vehicle size, maximum speed, braking capacity, and hydraulic response delay to form a dynamic danger zone and issue a stop command. At the same time, the current speed profile is frozen to prevent further forward movement due to delay. This mechanism forms a complete safety link from risk prediction, warning adjustment to emergency braking, significantly improving the safety of unmanned compaction cluster operations. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 The flowchart of the preferred embodiment of the present application is shown. DETAILED DESCRIPTION

[0082] The present application will be further described below in conjunction with the drawings and examples.

[0083] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0084] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application; as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, it will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components, and / or groups thereof.

[0085] The present application provides a master-slave collaborative spatiotemporal planning control method for group-oriented compaction operation, referring to Figure 1 , which can realize dynamic partitioning, path planning and safety collision avoidance control of multiple road rollers in the same construction area, and improve the construction efficiency and safety of unmanned compaction operation.

[0086] Step 1: Construction area boundary determination and equal-area grid division, the master device determines the boundary points through the RTK positioning system, obtains the boundary coordinate information of the rectangular construction area, establishes a reference coordinate system, and converts the received longitude, latitude and height into the Northeast coordinate system by the following formula:

[0087] ,

[0088]

[0089] Combined with the number M of road rollers and the total area of the region Divide the region into N sub-regions along the X and Y axes of the Northeast coordinate system, and automatically calculate the theoretical area of single-vehicle operation partition:

[0090]

[0091] When N is even, two columns of N / 2 rows of block-shaped regions are formed; when N is odd, two columns of (N+1) / 2 block-shaped regions are formed. The size of each sub-region is determined according to the length and the width of the rectangular boundary according to the following formula:

[0092] ,

[0093] Where represents the upward rounding.

[0094] The division result forms a set of rectangular grid regions:

[0095]

[0096] All regions are numbered in order from left to right and from top to bottom:

[0097] , ,..., , ...

[0098] Subsequently, each sub-grid area is assigned to the corresponding road roller according to the road roller number, and the four vertex coordinates and boundary parameters of the area are issued to each vehicle.

[0099] Step 2: Generate the initial path of the road roller by a third-order Bezier curve and curvature constraint. Each road roller generates a local path from the initial position to the starting point of the target work area. To prevent large steering during driving, which may reduce the quality of road rolling, a third-order Bezier curve is used to plan an ideal path. The specific formula is as follows:

[0100]

[0101] Wherein: : the current initial position of the road roller; : the starting point of the target work area; , : the intermediate control point dynamically generated according to the initial orientation and target direction, used to control the curvature shape.

[0102] The maximum allowed curvature is set during planning , Through iterative adjustment of the control point ,

[0103]

[0104] The curvature formula of the third-order Bezier curve is:

[0105]

[0106] Where and are functions of the position of the curve in the plane.

[0107] Step 3: Multi-machine path coordination based on space-time constraints. After each road roller plans the local path from the current position to the starting point of the target area, the speed of each point is assigned, and the expected time required to complete the path is calculated. When the vehicle is driving on the interval , , the time from point k to k+1 is:

[0108]

[0109] The expected arrival time of the i-th vehicle at the k-th point is:

[0110]

[0111] wherein, is the time when the roller starts to perform the path at the initial moment, to ensure that each roller is uniform on the global time axis.

[0112] Since the roller positioning device is installed in the middle section of the vehicle body, considering the size of the vehicle, a certain time is reserved for the front and rear vehicle bodies when the actual roller passes through the path point, so that the roller passes through the path point The corresponding occupation time is:

[0113]

[0114] wherein and is the time reserved for the roller to enter and leave the path point.

[0115] Upload the expected time to the master device, and the master device performs space-time modeling on the path corresponding to the expected time of all rollers, establishes the correspondence between the time window and the space grid, maps the path point position to the grid set, and finds all grid sets G that satisfy , the grid that satisfies the condition and the time interval corresponding to the occupation, then each time sampling point in the time interval is marked as occupied grid occupation is expressed as .

[0116] If there is any grid that satisfies in the same time interval, it means that there is at least two rollers that overlap in the same time interval, and there is a space-time conflict.

[0117] If a space-time conflict occurs, the expected time of each roller to the starting point of the target area is used as the priority judgment basis, and the longer the time spent, the lower the priority. For the roller with low priority in the conflict, the speed is scaled by multiplying :

[0118]

[0119] At this time, the speed profile is:

[0120]

[0121] wherein = 0.5, the initial value is 1.0, the speed scaling value is reduced by 0.05 each time, and the space-time occupation is detected to determine whether it overlaps, thereby resolving the conflict.

[0122] Step 4: Real-time state synchronization and security protection mechanism, in the process of work, all road rollers broadcast their own position information at a fixed frequency, and the real-time distance between each two road rollers (i, j) is calculated , set the safety distance ,

[0123] (1) Normal state (outside the safety distance), when , it is considered that there is no collision risk between the two vehicles, and each road roller maintains the original speed planning instruction for rolling operation.

[0124] (2) Warning state (approaching safety distance), when , the system enters the warning state, the master device determines the relationship type of the two vehicles through the projection difference in the direction of the previously divided region and the coordinate axis, sets the working bandwidth , for the front-back relationship on the same working band: if , it means that the positions of the two vehicles belong to the front-back relationship, and if , then is in front of ; if , then is behind . For the left-right relationship of adjacent working bands, if , it means that the positions of the two vehicles belong to the left-right relationship, and if , then is on the left side of ; if , then is on the right side of .

[0125] Priority setting:

[0126] If it is a front-back relationship (front-back vehicles in the same rolling direction), the rear vehicle performs speed scaling , where =0.5,

[0127] The initial value is 1.0, and the speed scaling value is reduced by 0.05 each time, and the real-time distance between the two vehicles is detected to return to the normal state to remove the warning state;

[0128] If it is a left-right relationship (parallel operation of adjacent working bands), the right road roller performs speed scaling to maintain the lateral safety distance.

[0129] (3) Dangerous state (approaching collision threshold), when , the system considers that there is a potential collision risk and enters the dangerous state. At this time, the master device starts the emergency collision avoidance mechanism and executes the multi-machine safety strategy:

[0130] (i) Priority judgment and region locking:

[0131] The main equipment first determines the "main vehicle" and the "avoiding vehicle" based on the priority of the work tasks, and temporarily establishes a local "safe no-entry zone" within the work area. For the main vehicle i and the avoiding vehicle j, assume their current coordinates are:

[0132]

[0133] Construct a minimum bounding box (AABB) using two points:

[0134]

[0135]

[0136] The initial collision box is obtained:

[0137]

[0138] To account for vehicle size, emergency braking error, and communication delay, the area is expanded outwards by the following distance:

[0139]

[0140] in The maximum operating speed of the vehicle. Response time

[0141] Perform Minkowski dilation calculation; the danger zone after dilation:

[0142]

[0143] Map the hazardous area onto a grid. For all grid sets G, if its center... satisfy:

[0144]

[0145] If the grid status is marked as "prohibited", that is, it is marked as occupied on the time window corresponding to the grid. If other road rollers plan to pass through the "prohibited" grid, the path will be replanned to avoid secondary risks.

[0146] (ii) Forced coverage of velocity profile:

[0147] An emergency stop order is immediately issued to the vehicle attempting to avoid it. Considering the response delays of the road roller's hydraulic system and communication link, the speed planning for the vehicle's current route segment is simultaneously frozen to prevent the vehicle from continuing to travel according to the planned speed.

[0148]

[0149] The host device detects the speed feedback value in real time in the subsequent cycle, and confirms that the emergency stop is completed when the actual speed is detected to be less than 0.05 m / s.

[0150] (iii) Anti-collision buffer mechanism:

[0151] To avoid collision between the two vehicles within the deceleration delay, the system sends a brake command to the host vehicle according to the host vehicle brake acceleration and the response time to predict the shortest stopping distance:

[0152]

[0153] If , the system sends a brake command to the host vehicle synchronously.

Claims

1. A master-slave collaborative spatiotemporal planning and control method for group compaction operations, characterized in that, Includes the following steps: Step 1: Determine the boundaries of the construction area and divide it into equal-area grids; Step 2: Generate the starting path of the road roller using third-order Bézier curves and curvature constraints. Each road roller generates a local path to the starting point of the target work area based on its own initial position. Step 3: Multi-machine path coordination based on spatiotemporal constraints. After each road roller has completed its local path planning from its current position to the starting point of the target area, a speed value is assigned to each point, and the expected time required to complete the path is calculated. Step 4: Establish a real-time status synchronization and safety protection mechanism. During operation, all road rollers broadcast their own position information at a fixed frequency, and calculate the real-time distance between any two road rollers (i,j). Set a safe distance By determining the real-time distance and safe distance To avoid collisions between the two road rollers.

2. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 1, characterized in that, Step 1 includes: The main equipment uses the RTK positioning system to obtain boundary points, acquires the boundary coordinate information of the rectangular construction area, establishes a reference coordinate system, and converts the received latitude, longitude, and altitude into the northeast-southeast coordinate system using the following formula: ， in Here, E represents the eastward offset, N represents the northward offset, and U represents the vertical offset. The geocentric and geofixed coordinates of the target point. The geocentric coordinates of the reference point This represents the coordinate difference between the target point and the reference point in the Earth-centered, Earth-fixed coordinate system. Where R is the rotation matrix, which rotates and aligns the axes of the Earth coordinate system to the northeast-sky direction of the reference point. The accuracy of the reference point is expressed in radians. The dimension of the reference point is in radians; Combining the number of road rollers M and the total area of ​​the rectangular construction area The rectangular construction area is divided into N sub-regions with equal spacing and area along the X and Y axes of the northeast-central coordinate system, where the number of N is the same as the number of M. The theoretical area of ​​each vehicle's work zone is automatically calculated. When N is even, two columns of N / 2 rows of block regions are formed; when N is odd, two columns of (N+1) / 2 block regions are formed; the size of each sub-region is based on the length of the rectangular boundary. ,width Determine using the following formula: , ,in Indicates rounding up; The partitioning results in a set of rectangular grid regions R. (a,b) : All areas are numbered sequentially from left to right and from top to bottom: , ,..., , ,... Then, each subgrid area is assigned to the corresponding road roller according to the road roller number, and the coordinates of the four vertices and boundary parameters of the area are sent to each vehicle.

3. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 1, characterized in that, Step 2 includes: planning the ideal path B(t) using a third-order Bézier curve, with the specific formula: , ,in: This indicates the current initial position of the road roller; Indicates the starting point of the target work area; This represents the intermediate control points dynamically generated based on the initial orientation. These represent intermediate control points dynamically generated based on the target direction, used to control the curvature shape. The maximum allowable curvature is set during the planning process. By dynamically generating intermediate control points based on the initial orientation Intermediate control points dynamically generated based on the target direction Iterative adjustments ensure that the planned curvature is less than or equal to the maximum permissible curvature: in This represents the magnitude of the curvature of the curve at time t. max Indicates the maximum permissible curvature value; The curvature formula for a third-order Bézier curve is: in and Let the coordinates of the curve be the coordinates of the curve on the two-dimensional plane. and The first derivative of the coordinate position with respect to time t. and Let be the second derivative of the coordinate position with respect to time t.

4. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 1, characterized in that, Step 3 includes: setting the road roller in the section [ , When traveling on the road, the time Δt from point k to k+1 is... i,k : Then the estimated arrival time of the i-th road roller at the k-th point is: ,in, This is the time at which the road roller begins executing its path from the initial moment. Road roller passes through path points Corresponding time interval for: in and Allow time for the road roller to enter and leave the path point.

5. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 4, characterized in that, Step 3 also includes: uploading the desired time to the main device; the main device performs spatiotemporal modeling on the paths corresponding to the desired times of all road rollers; establishing the correspondence between time windows and spatial grids; mapping the path point locations to grid sets; and finding all grid sets G that satisfy... , matching the raster that meets the conditions with the time interval Correspondingly, if marked as occupied, then within the time interval Each time sampling point within Marker grid occupancy is represented as ; If, within the same time interval, there exists any raster that satisfies This indicates that at least two road rollers are occupying overlapping areas in the same time interval, resulting in a spatiotemporal conflict. If a spatiotemporal conflict occurs, the expected time for each road roller to reach the starting point of the target area is used as the priority criterion; the longer the time, the lower the priority. For road rollers with low priority in a conflict, the priority is scaled by multiplying by the speed. : Where v i Let α be the real-time target speed of the i-th roller after adjustment, and let α be the speed scaling factor, which is between... between; The velocity profile at this point is: in Let be the coordinates of the path point of the i-th road roller. This constitutes the control command set for the speed of the road roller at the coordinates of the path points. set up =0.5, α is initially 1.0, the velocity scaling value is reduced by 0.05 each time, and the system continuously checks whether the spacetime occupancy overlaps, thereby resolving the conflict.

6. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 1, characterized in that, Step 4 includes: the status between the two rollers includes: when At this time, it is considered to be a normal state, and it is assumed that there is no risk of collision between the two road rollers. Each road roller maintains the original speed planning command to carry out compaction operations. when In the early warning state, the main equipment determines the relationship between the two road rollers based on the previously divided areas and the projection differences along the coordinate axes, and sets the operating bandwidth accordingly. Regarding the sequential relationship within the same work belt: if This indicates that the two vehicles are positioned in a front-to-back relationship. Where, if ,but exist Ahead; if ,but exist Behind; regarding the left-right relationship of adjacent work zones, if This indicates that the two cars are positioned in a left-right relationship. ,but exist The left side; if ,but exist The right side; when When the situation is dangerous, the main equipment will activate the emergency anti-collision mechanism and execute the multi-machine safety strategy.

7. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 1, characterized in that, In step 4, when the two road rollers are in a warning state, a priority is set: If the vehicles are in a front-to-back relationship (i.e., two vehicles traveling in the same direction), then the speed of the following vehicle will be scaled. ,in =0.5, The initial value is 1.0, and the speed scaling value decreases by 0.05 each time. The system continuously checks whether the real-time distance between the two vehicles returns to normal in order to cancel the warning status. If the work is in a left-right relationship, i.e., adjacent work zones are operating in parallel, the right-side roller is instructed to adjust its speed to maintain a safe lateral distance.

8. The master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 1, characterized in that, In step 4, when there is a dangerous situation between the two road rollers, priority judgment and area blockade are performed: The main equipment first determines the "main vehicle" and the "yielding vehicle" according to the priority of the work task, and temporarily establishes a local "safe restricted area" in the work area. For the main vehicle i and the yielding vehicle j, assume their current coordinates are: Construct a minimum bounding box AABB using two points: The initial collision box is obtained: The region expands outwards by the following distance: in This is the maximum operating speed of the road roller. Response time; Perform Minkowski dilation calculation; the danger zone after dilation: Map the hazardous area onto a grid. For all grid sets G, if its center... satisfy: If the grid status is marked as "prohibited", that is, it is marked as occupied on the time window corresponding to the grid. If other road rollers plan to pass through the "prohibited" grid, the path will be replanned to avoid secondary risks.

9. A master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 8, characterized in that, In step 4, when a dangerous situation arises between the two road rollers, an emergency stop order is immediately issued to the vehicle attempting to avoid the collision, and the speed plan for the vehicle's current path segment is frozen to prevent the road roller from continuing to travel according to the speed plan. The main equipment monitors the vehicle's speed feedback value in real time during subsequent cycles. When the actual speed is detected to be less than 0.05 m / s, the emergency stop is confirmed to be completed.

10. A master-slave collaborative spatiotemporal planning and control method for group compaction operations according to claim 9, characterized in that, In step 4, when the two road rollers are in a dangerous situation, the system determines the braking acceleration based on the main vehicle's braking force. Shortest stopping distance from response time prediction: like At that time, the system simultaneously sends a braking command to the main vehicle.

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