A method and system for unmanned cleaning vehicles to form a platoon for cleaning in a park.

Abstract

This invention belongs to the field of autonomous driving sweeper technology, specifically a method and system for unmanned sweeper platooning in industrial parks. It includes: 1. Initializing the platoon formation; 2. Forming the platoon, if successful, proceeding to step 3; otherwise, returning to step 1; 3. The platoon enters the sweeping state, adjusting the formation in real-time according to the road width, if an obstacle is encountered, proceeding to step 4; otherwise, continuing sweeping; 4. When encountering an obstacle, determining whether obstacle avoidance can be achieved by changing the formation, if so, assuming the road is narrowing, returning to step 3; otherwise, proceeding to step 5; 5. Generating an obstacle avoidance trajectory and performing obstacle avoidance, returning to step 3 after obstacle avoidance is completed; 6. The unmanned sweeper platoon completes a single sweeping task and returns from the endpoint to the starting point. This invention can autonomously select a platoon formation for sweeping and obstacle avoidance based on current road conditions and through interaction between vehicles, achieving as much full coverage sweeping as possible and solving the problem of blind spots in sweeping with a single unmanned sweeper.

Description

Technical Field

[0001] This invention belongs to the field of autonomous driving sweeper technology, specifically a method and system for unmanned sweeper platooning in a park. Background Technology

[0002] With the rapid development of vehicle electrification and intelligence, autonomous driving technology, as the future direction of automotive development, has always received high attention from all sectors of society. As my country's urban penetration rate and infrastructure construction increase, people's demands for urban environments are also rising. Sweepers are playing an increasingly important role in urban sanitation. Low-speed, small-sized unmanned sweepers developed by combining autonomous driving technology with the sanitation field can not only liberate people from mechanical and repetitive labor, but also effectively avoid the harm to sanitation workers caused by traffic accidents, weather conditions, and working overtime in the early morning, possessing both commercial and social value. However, a single unmanned sweeper can only sweep along a relatively narrow width, failing to achieve full road coverage and leaving blind spots in the cleaning process. Because parks are relatively enclosed and road conditions are relatively simple, unmanned sweepers can easily achieve full road coverage by sweeping in platoons, and the problem of cleaning blind spots can be solved by the cooperation of different sweepers. Furthermore, because unmanned sweeper platoons have multiple sets of sensors, they can perceive more comprehensive information and have stronger obstacle detection and positioning capabilities. Summary of the Invention

[0003] This invention provides a method and system for unmanned sweeping vehicles to form a platoon for sweeping in a park. Based on the current road conditions, the vehicles can autonomously select a platoon formation for sweeping through interaction, avoid obstacles, and achieve full coverage of the road surface as much as possible, thus solving the problem of blind spots in sweeping by a single unmanned sweeping vehicle.

[0004] The technical solution of this invention is described below in conjunction with the accompanying drawings:

[0005] In a first aspect, the present invention provides a method for platooning unmanned cleaning vehicles to clean a park, comprising the following steps:

[0006] Step 1: The lead unmanned sweeper determines the width of the road surface to be swept based on the map and location information, and selects and calculates the initial formation.

[0007] Step 2: The following unmanned cleaning vehicles form a formation according to the formation selected by the lead unmanned cleaning vehicle. If the formation is successful, proceed to Step 3; otherwise, return to Step 1.

[0008] Step 3: The convoy enters the cleaning state. The lead unmanned cleaning vehicle adjusts its formation in real time according to the road width. If it encounters an obstacle, proceed to step 4; otherwise, continue cleaning.

[0009] Step 4: When encountering an obstacle, the lead sweeper determines whether it can avoid the obstacle by changing its formation. If it can, it is considered that the road is narrowing and returns to step 3; otherwise, proceed to step 5.

[0010] Step 5: The lead unmanned sweeping vehicle sends a command to arrange the three unmanned sweeping vehicles in a longitudinal row. The lead unmanned sweeping vehicle performs motion planning and generates an obstacle avoidance trajectory. The following unmanned sweeping vehicles follow the trajectory planned by the lead unmanned sweeping vehicle to avoid obstacles. After obstacle avoidance is completed, return to step 3.

[0011] Step Six: The unmanned cleaning vehicles form a platoon to complete a single cleaning task and return to the starting point from the endpoint.

[0012] Furthermore, the specific method for step one is as follows:

[0013] 11) Collect environmental data for the park and create a map;

[0014] 12) The unmanned sweeping vehicle, based on the map established in step 11), matches the environmental information perceived by the unmanned sweeping vehicle's lidar with the GPS signal to determine its position on the map; after determining the position, it determines the width L of the road to be swept based on the road information collected from the map.

[0015] 13) Select the formation based on the width L of the road to be cleaned.

[0016] Furthermore, the specific method for step 13) is as follows:

[0017] The formation includes a first formation and a second formation. The first formation has a lead unmanned sweeper in front, with two following unmanned sweepers traveling side by side on the same horizontal line, forming an isosceles triangle. The first formation is used for sweeping wide roads, and can cover a sweeping width of L0+δ to 3L0, where L0 is the sweeping width of a single unmanned sweeper, and δ is the minimum distance between the center lines of the two following unmanned sweepers when they travel side by side.

[0018] The second formation consists of a lead unmanned sweeper vehicle in front, followed by two other unmanned sweepers, one in front of the other, forming an obtuse triangle. This second formation is used for sweeping narrow roads and can cover a sweeping width of L0 to L0+δ, where L0 is the sweeping width of a single unmanned sweeper vehicle, and δ is the minimum distance between the center lines of the two following unmanned sweepers when they are driving side by side.

[0019] When L>3L0, the unmanned sweeper platoon cannot achieve full coverage cleaning. It will inform the user that the current road cannot be fully covered and ask the user whether to continue cleaning. If the user confirms to continue cleaning, the platoon will be initialized according to the first platoon formation.

[0020] When \(L_0 + \delta\leq L\leq3L_0\), initialize the formation according to the first formation pattern;

[0021] When \(L_0\leq L\leq L_0 + \delta\), initialize the formation according to the second formation pattern;

[0022] When \(L < L_0\), feedback to the user that the current road cannot be cleaned.

[0023] Furthermore, the specific method of step 2 is as follows:

[0024] 21) Calculate the expected distance, angle between two following unmanned cleaning vehicles, and the position, attitude and speed of the leading unmanned cleaning vehicle, and then transmit them to the coprocessor of the following unmanned cleaning vehicle through the local area network by the host computer;

[0025] 22) The following unmanned cleaning vehicle calculates the error between its current position and attitude and the expected position and attitude based on its own position, attitude and speed, as well as the position, attitude, speed, expected distance and angle of the leading unmanned cleaning vehicle, and then obtains its own motion control information and generates a control instruction to send to the motion control module;

[0026] 23) The motion control module analyzes the control instruction to generate a PWM control signal; controls the motor to rotate so that the unmanned cleaning vehicle reaches the expected position and attitude, and then completes the initialization of the formation of the unmanned cleaning vehicle; after the unmanned cleaning vehicle reaches the expected position and attitude, it sends its own position and attitude to the leading unmanned cleaning vehicle, and the leading unmanned cleaning vehicle judges whether the formation is completed. If not, step 2 is executed again.

[0027] Furthermore, the specific method of step 22) is as follows:

[0028] The kinematic model of the following unmanned cleaning vehicle is as follows:

[0029]

[0030] In the formula, \(f\) is the following unmanned cleaning vehicle; \(v\) f is the speed of the following unmanned cleaning vehicle; is the speed of the following unmanned cleaning vehicle in the \(x\) direction, that is, the projection of \(v\) f in the \(x\) direction; is the speed of the following unmanned cleaning vehicle in the \(y\) direction, that is, the projection of \(v\) f in the \(y\) direction; \(\theta\) f is the heading angle of the following unmanned cleaning vehicle, that is, the angle between the velocity vector \(v\) f and the positive direction of the \(x\)-axis; and \(\omega\) fω is the angular velocity of the following unmanned sweeper; b is the distance between the center of mass and the rear axle of the vehicle.

[0031] The desired location of the following sweeper is:

[0032]

[0033] In the formula, f represents the following unmanned cleaning vehicle; l represents the leading unmanned cleaning vehicle; The desired x-coordinate of the following unmanned cleaning vehicle; The desired y-coordinate of the following unmanned cleaning vehicle; The desired heading angle of the following unmanned cleaning vehicle is assumed to be the same as that of its leader vehicle, meaning the leader vehicle always expects the following vehicle to have the same heading angle. x l The x-coordinate of the leading unmanned cleaning vehicle; y-coordinate l The y-coordinate of the leading unmanned cleaning vehicle; θ l The heading angle of the unmanned cleaning vehicle for navigation; The expected distance between the following and leading unmanned cleaning vehicles; The expected relative turning angle between the following autonomous cleaning vehicle and the leading autonomous cleaning vehicle;

[0034] The error between the expected position and heading angle of the following unmanned cleaning vehicle and its actual position and heading angle is:

[0035]

[0036] In the formula, The error in the x-coordinate of the following unmanned cleaning vehicle; The error in the y-coordinate of the following unmanned sweeper; The error in the θ coordinate of the following unmanned sweeper; x f The x-coordinate of the following unmanned cleaning vehicle; the y-coordinate. f The y-coordinate of the following unmanned cleaning vehicle;

[0037] Differentiating the position and heading angle errors yields:

[0038]

[0039] In the formula, ω l The angular velocity of the leading sweeper;

[0040] Based on the vehicle kinematics model of the following unmanned sweeper vehicle, the trajectory tracking error model of the unmanned sweeper vehicle formation is derived as follows:

[0041]

[0042] Furthermore, the specific method for step four is as follows:

[0043] The lead sweeper senses an obstacle at a distance d from its centerline, and the width of the lead sweeper is L0. If d > L0 / 2, the sweeper formation is considered to be able to avoid obstacles by shrinking its formation, and no path planning is required; the sweepers switch to the second formation. If d ≤ L0 / 2, the sweeper formation is considered to be unable to avoid obstacles by changing its formation, and path planning is required.

[0044] Furthermore, the specific method for step five is as follows:

[0045] When the unmanned sweeping vehicle convoy cannot avoid obstacles by shrinking its formation, the lead sweeping vehicle sends a command to cause the two following unmanned sweeping vehicles to follow behind the lead sweeping vehicle, with the three forming a line in the longitudinal direction. The lead sweeping vehicle uses the Hybrid A* algorithm to generate a trajectory. The lead sweeping vehicle leads the convoy along the planned trajectory until obstacle avoidance is completed and it returns to the sweeping state.

[0046] Secondly, the present invention provides a platooning cleaning system for unmanned park cleaning vehicles, used to implement a platooning cleaning method for unmanned park cleaning vehicles, including:

[0047] The coprocessor is used to calculate its own motion information based on the desired pose input from the host computer, generate control commands, receive sensor signals, and transmit perception and positioning information to the host computer.

[0048] The motion control module is used to receive control commands from the co-controller, parse the control commands, and input PWM control signals to the control execution module.

[0049] The motion execution module is used to enable the unmanned sweeper to move according to the desired pose and to feed back encoder signals to the control module.

[0050] The sensor module is used to sense surrounding obstacles and road information, locate the vehicle, and calculate vehicle speed and acceleration;

[0051] The host computer is used for environmental perception, motion planning, formation decision-making, and collaborative communication among multiple unmanned sweeping vehicles.

[0052] The sweeping module is used for road sweeping and watering.

[0053] Furthermore, the lead unmanned sweeping vehicle is equipped with a coprocessor, motion control module, motion execution module, sensor module, sweeping function module, and host computer; the following unmanned sweeping vehicles are equipped with a coprocessor, motion control module, motion execution module, sensor module, and sweeping function module.

[0054] The beneficial effects of this invention are as follows:

[0055] 1) The unmanned sweeping vehicle platooning system provided by this invention has a wide range of applications and improves the intelligence level of the sweeping vehicle through the interconnection between different functional modules;

[0056] 2) This invention can automatically select the formation mode based on the current road conditions and obstacle information to complete functions such as formation clearing and obstacle avoidance;

[0057] 3) Based on the obstacle distance information, the present invention can autonomously select one of two obstacle avoidance methods. When the obstacle is far away, obstacle avoidance can be achieved by shrinking the formation, without the need for path planning, thus saving the computing power of the host computer.

[0058] 4) This invention can easily transfer the host computer module of the lead sweeper to the follow sweeper, thereby changing the role of the unmanned sweeper in the formation and avoiding the situation where the entire unmanned sweeper formation cannot work when the lead sweeper malfunctions.

[0059] 5) This invention innovatively proposes the "unmanned sweeping vehicle platooning cleaning concept", which improves the efficiency of cleaning work by using multiple unmanned sweeping vehicles in platoons compared to the previous single-operation unmanned sweeping vehicles. Attached Figure Description

[0060] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a schematic diagram of the architecture of a platoon-style unmanned cleaning vehicle system for a park, as described in this invention.

[0062] Figure 2 This is a schematic diagram illustrating the workflow of a method for platooning unmanned cleaning vehicles in a park, as described in this invention.

[0063] Figure 3a This is a schematic diagram of the formation of the first squadron;

[0064] Figure 3b This is a schematic diagram of the second formation;

[0065] Figure 4 This is a schematic diagram of the control workflow in the unmanned park cleaning vehicle platoon cleaning method described in this invention;

[0066] Figure 5a A schematic diagram illustrating the obstacle avoidance maneuvering of a platoon of unmanned cleaning vehicles under a specific working condition.

[0067] Figure 5b A schematic diagram illustrating the obstacle avoidance maneuvering of an unmanned sweeping vehicle platoon under another working condition;

[0068] Figure 6 This is a schematic diagram of the obstacle avoidance process in the unmanned park cleaning vehicle platoon cleaning method described in this invention. Detailed Implementation

[0069] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] Example 1

[0071] See Figure 2 This invention provides a method for platooning unmanned cleaning vehicles in a park, wherein there are three unmanned cleaning vehicles, including one lead unmanned cleaning vehicle and two follower unmanned cleaning vehicles;

[0072] The cleaning method includes the following steps:

[0073] Step 1: The lead unmanned sweeper determines the width of the road surface to be swept based on the map and location information, and selects and calculates the initial formation; the specific method is as follows:

[0074] 11) Use sensor modules to collect environmental data from the park and create a map;

[0075] 12) The unmanned sweeping vehicle, based on the map established in step 11), matches the environmental information perceived by the unmanned sweeping vehicle's lidar with the GPS signal to determine its position on the map; after determining the position, it determines the width L of the road to be swept based on the road information collected from the map.

[0076] 13) Select the formation based on the width L of the road to be cleaned, as follows:

[0077] See Figure 3a and Figure 3b The formation includes a first formation and a second formation. The first formation has a lead unmanned sweeper in front, with two following unmanned sweepers traveling side by side on the same horizontal line, forming an isosceles triangle. The first formation is used for sweeping wide roads, and can cover a sweeping width of L0+δ~3L0, where L0 is the sweeping width of a single unmanned sweeper, and δ is the minimum distance between the center lines of the two following unmanned sweepers when they travel side by side.

[0078] The formation of the second group is that the leading unmanned sweeper is in the front, and two following unmanned sweepers follow behind the leading sweeper, one in front and the other behind, and the three drive in an obtuse triangle; the second formation is used for cleaning narrow roads, and the cleaning width that can be covered is L0 to L0+δ, where L0 is the cleaning width of a single unmanned sweeper; δ is the minimum distance between the center lines of the two following unmanned sweepers when driving side by side.

[0079] When L>3L0, the formation of the unmanned sweepers cannot achieve full-coverage cleaning. Feedback to the user that the current road cannot achieve full-coverage cleaning, and ask the user whether to continue cleaning. If the user confirms to continue cleaning, initialize the formation according to the first formation.

[0080] When L0+δ≤L≤3L0, initialize the formation according to the first formation.

[0081] When L0≤L≤L0+δ, initialize the formation according to the second formation.

[0082] When L<L0, feedback to the user that the current road cannot be cleaned.

[0083] Refer to Figure 4 , Step 2: The following unmanned sweepers form a formation according to the formation selected by the leading unmanned sweeper. If the formation is successful, execute Step 3, otherwise return to Step 1; that is, the leading unmanned sweeper sends its own pose (x l , y l , θ l ) and the expected distance and angle Based on this, the following unmanned sweepers calculate the expected pose and the error between the current pose and the expected pose The following unmanned sweepers calculate the speed and angular velocity of the sweeper in real time according to this error and the formation trajectory tracking error model, generate control instructions and control signals to control the vehicle to reach the expected position and attitude. When the formation is completed, feedback its own position and attitude to the leading unmanned sweeper to determine whether it meets the formation requirements. Specifically as follows:

[0084] 21) Calculate the expected distance and angle of the two following unmanned sweepers and the position, attitude and speed of the leading unmanned sweeper itself, and then transmit them to the coprocessor of the following unmanned sweeper through the local area network by the upper computer. ​​

[0086] The kinematic model of the following unmanned cleaning vehicle is as follows:

[0087]

[0088] In the formula, f represents the following unmanned cleaning vehicle; v f The speed of the following unmanned cleaning vehicle; Let v be the velocity of the following unmanned sweeper in the x-direction. f Projection in the x-direction; Let v be the velocity of the following unmanned sweeper in the y-direction. f Projection in the y-direction; θ f The heading angle of the following unmanned sweeper, i.e., the velocity vector v. f The angle with the positive x-axis; and ω f ω is the angular velocity of the following unmanned sweeper; b is the distance between the center of mass and the rear axle of the vehicle.

[0089] The desired location of the following sweeper is:

[0090]

[0091] In the formula, f represents the following unmanned cleaning vehicle; l represents the leading unmanned cleaning vehicle; The desired x-coordinate of the following unmanned cleaning vehicle; The desired y-coordinate of the following unmanned cleaning vehicle; The desired heading angle of the following unmanned cleaning vehicle is assumed to be the same as that of its leader vehicle, meaning the leader vehicle always expects the following vehicle to have the same heading angle. x l The x-coordinate of the leading unmanned cleaning vehicle; y-coordinate l The y-coordinate of the leading unmanned cleaning vehicle; θ l The heading angle of the unmanned cleaning vehicle for navigation; The expected distance between the following and leading unmanned cleaning vehicles; The expected relative turning angle between the following autonomous cleaning vehicle and the leading autonomous cleaning vehicle;

[0092] The error between the expected position and heading angle of the following unmanned cleaning vehicle and its actual position and heading angle is:

[0093]

[0094] In the formula, The error in the x-coordinate of the following unmanned cleaning vehicle; The error in the y-coordinate of the following unmanned sweeper; The error in the θ coordinate of the following unmanned sweeper; x f The x-coordinate of the following unmanned cleaning vehicle; the y-coordinate. f The y-coordinate of the following unmanned cleaning vehicle;

[0095] Differentiating the position and heading angle errors yields:

[0096]

[0097] In the formula, ω l The angular velocity of the leading sweeper;

[0098] Based on the vehicle kinematics model of the following unmanned sweeper vehicle, the trajectory tracking error model of the unmanned sweeper vehicle formation is derived as follows:

[0099]

[0100] 23) The motion control module parses the control commands and generates PWM control signals; controls the motor to rotate so that the unmanned sweeper reaches the desired position and posture, thereby completing the unmanned sweeper formation initialization; after the unmanned sweeper reaches the desired position and posture, it sends its own position and posture to the lead unmanned sweeper, which then determines whether the formation is complete. If not, step two is executed again.

[0101] At this point, the unmanned sweeper formation problem has been transformed into a trajectory following problem. The lead sweeper sends its position, attitude, speed, and desired distance and angle information to the following sweepers via a host computer. The following sweepers calculate their own motion control information in real time based on their position, attitude, and speed, and generate control commands, which are then sent to the motion control module. The motion control module parses the control commands, generates PWM control signals, and controls the motors to rotate, enabling the sweepers to reach the desired position and attitude, thus completing the sweeper formation initialization. After reaching the desired position and attitude, each sweeper sends its position and attitude back to the lead sweeper. The lead sweeper then determines whether formation is complete; if not, the process is repeated.

[0102] Step 3: The convoy enters the cleaning state. The lead unmanned cleaning vehicle adjusts its formation in real time according to the road width. If it encounters an obstacle, proceed to step 4; otherwise, continue cleaning.

[0103] The unmanned sweeping vehicle, based on map information and perceived information, calculates the width of the passable road ahead in real time, selects a suitable formation, and controls the formation to move forward in real time. The specific control method is the same as in step two.

[0104] See Figure 5a and Figure 5bStep four: When encountering an obstacle, the lead sweeper determines whether it can avoid the obstacle by changing its formation. If it can, it is considered that the road is narrowing, and it returns to step three; otherwise, it proceeds to step five. The specific method is as follows:

[0105] The lead sweeper senses an obstacle at a distance d from its centerline, and the width of the lead sweeper is L0. If d > L0 / 2, the sweeper formation is considered to be able to avoid obstacles by shrinking its formation, and no path planning is required; the sweepers switch to the second formation. If d ≤ L0 / 2, the sweeper formation is considered to be unable to avoid obstacles by changing its formation, and path planning is required.

[0106] See Figure 6 Step 5: The lead unmanned sweeper sends a command to arrange the three sweepers in a longitudinal row. The lead sweeper performs motion planning and generates an obstacle avoidance trajectory. The following sweepers follow the trajectory planned by the lead sweeper to avoid obstacles. After obstacle avoidance is completed, return to step 3. The specific method is as follows:

[0107] When the unmanned cleaning vehicles encounter obstacles, there are two scenarios. In one scenario, the obstacle will collide with the entire formation but not with the lead cleaning vehicle. In this case, obstacle avoidance can be achieved by shrinking the formation. In the other scenario, the obstacle will collide with the lead cleaning vehicle. In this case, obstacle avoidance by shrinking the formation is no longer possible. In this situation, the lead cleaning vehicle issues a command to arrange the entire formation in a longitudinal line and uses the Hybrid A* algorithm to generate a trajectory that can bypass the obstacle. The entire formation moves along the trajectory to achieve obstacle avoidance.

[0108] Step Six: The unmanned cleaning vehicles form a platoon to complete a single cleaning task and return to the starting point from the endpoint.

[0109] The sweeper truck determines whether it has completed platooning. If not, it repeats step two.

[0110] Example 2

[0111] See Figure 1 This invention provides a platooning cleaning system for unmanned park cleaning vehicles, used to implement a platooning cleaning method for unmanned park cleaning vehicles, including:

[0112] The coprocessor is used to calculate its own motion information based on the desired pose input from the host computer, generate control commands, receive sensor signals, and transmit perception and positioning information to the host computer.

[0113] Specifically, the coprocessor includes an embedded microcontroller used to calculate its own motion control information, send control commands to the controller, receive sensor signals, and transmit them to the host computer.

[0114] The motion control module is used to receive control commands from the co-controller, parse the control commands, and input PWM control signals to the control execution module.

[0115] Specifically, the motion control module includes a vehicle controller, which is used to parse control commands, send PWM control signals to the motor, and control its rotation.

[0116] The motion execution module is used to enable the unmanned sweeper to move according to the desired pose and to feed back encoder signals to the control module.

[0117] Specifically, the motion execution module includes a drive motor, a steering motor, and a brake motor, used to realize functions such as vehicle forward movement, steering, deceleration, and parking.

[0118] The sensor module is used to sense surrounding obstacles and road information, locate the vehicle, and calculate vehicle speed and acceleration;

[0119] Specifically, the sensor module includes a lidar, GPS, and an inertial vehicle unit, used to sense distance, detect obstacles, locate, and output information such as speed acceleration.

[0120] The host computer is used for environmental perception, motion planning, formation decision-making, and collaborative communication among multiple unmanned sweeping vehicles.

[0121] Specifically, the host computer includes an industrial control computer used to run the robot operating system ROS to perform tasks such as perception, localization, mapping, planning, and formation.

[0122] The sweeping module is used for road sweeping and watering.

[0123] Specifically, the sweeping module uses existing modules including sweeping brushes, water spraying devices, and trash cans to complete routine road sweeping work.

[0124] The lead unmanned sweeper is equipped with a coprocessor, motion control module, motion execution module, sensor module, sweeping function module, and host computer; the following unmanned sweeper is equipped with a coprocessor, motion control module, motion execution module, sensor module, and sweeping function module.

[0125] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the scope of protection of the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, any person skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention. These simple modifications are all within the scope of protection of the present invention.

[0126] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0127] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for cleaning a park by a formation of unmanned cleaning vehicles, characterized in that, The method comprises the following steps: Step one, the leading unmanned sweeper determines the width of the road to be swept according to the map and positioning information, selects and calculates the initial formation; Step two, the following unmanned sweeper forms a formation according to the formation selected by the leading unmanned sweeper, if the formation is successfully formed, step three is executed, otherwise, step one is returned; Step three, the vehicle formation enters the sweeping state, the leading unmanned sweeper controls and adjusts the formation in real time according to the road width, if an obstacle is encountered, step four is executed, otherwise, the sweeping continues; Step four, when an obstacle is encountered, the leading sweeper judges whether the obstacle can be avoided by changing the formation, if yes, it is considered that the road is narrowed, and step three is returned, otherwise, step five is executed; Step five, the leading unmanned sweeper sends a command to make the three unmanned sweepers form a row in the longitudinal direction, the leading unmanned sweeper plans a motion, generates an obstacle avoidance trajectory, and the following unmanned sweeper follows the trajectory planned by the leading unmanned sweeper to avoid the obstacle, and returns to step three after the obstacle avoidance is completed; Step six, the unmanned sweeper completes a single sweeping task and returns to the starting point from the end point; The specific method of step one is as follows: 11) Collecting the park environment data to establish a map; 12) The leading unmanned sweeper matches the map established in step 11) and the environment information sensed by the laser radar of the unmanned sweeper, and combines the GPS signal to determine the position of the sweeper in the map; after the position is determined, the road information collected from the map is used to determine the width L of the road to be swept; 13) Selecting a formation according to the width L of the road to be swept; The specific method of step 13) is as follows: The formation includes a first formation and a second formation; the first formation is that the leading unmanned sweeper is in front, and the two following unmanned sweepers are side by side on the same horizontal line, and the three form an isosceles triangle; the first formation is used for sweeping a wide road, and the sweeping width that can be covered is L0+δ~3L0, wherein L0 is the sweeping width of a single unmanned sweeper, and δ is the minimum distance between the center lines of the two following unmanned sweepers when they are side by side; The second formation is that the leading unmanned sweeper is in front, and the two following unmanned sweepers follow the leading sweeper in front and behind, and the three form an obtuse triangle; the second formation is used for sweeping a narrow road, and the sweeping width that can be covered is L0~L0+δ, wherein L0 is the sweeping width of a single unmanned sweeper, and δ is the minimum distance between the center lines of the two following unmanned sweepers when they are side by side; When L>3L0, the unmanned sweeper formation cannot realize full coverage sweeping, the user is fed back that the current road cannot realize full coverage sweeping, and it is asked whether the user continues to sweep, if the user confirms to continue to sweep, the first formation is used for initial formation; When L0+δ≤L≤3L0, the first formation is used for initial formation; When L0≤L≤L0+δ, the second formation is used for initial formation; When L<L0, the user is fed back that the current road cannot be swept.

2. The method of claim 1, wherein the method further comprises: The specific method of step two is as follows: 21) The expected distance and angle of the two following unmanned sweepers and the position, attitude and speed of the leading unmanned sweeper are calculated, and then transmitted to the coprocessor of the following unmanned sweeper through the local area network by the host computer; 22) The following unmanned sweeper calculates the error between the current position and attitude and the expected position and attitude according to the position, attitude and speed of the following unmanned sweeper and the position, attitude, speed, expected distance and angle of the leading unmanned sweeper, and then obtains the motion control information of the following unmanned sweeper and generates a control instruction to send to the motion control module; 23) The motion control module analyzes the control instruction and generates a PWM control signal; the motor is controlled to rotate to make the unmanned sweeper reach the expected position and attitude, and then the formation initialization of the unmanned sweeper is completed; after the unmanned sweeper reaches the expected position and attitude, the position and attitude of the unmanned sweeper are sent to the leading unmanned sweeper, and whether the formation is completed is judged by the leading unmanned sweeper; if not, step 2 is re-executed.

3. The park unmanned sweeper formation sweeping method according to claim 2, characterized in that, the specific method of step 22) is as follows: The kinematic model of the following unmanned sweeper is as follows: where f is the following unmanned sweeper; v f is the speed of the following unmanned sweeper; is the speed of the following unmanned sweeper in the x direction, i.e. v f is the projection in the x direction; is the speed of the following unmanned sweeper in the y direction, i.e. v f is the projection in the y direction; θ f is the heading angle of the following unmanned sweeper, i.e. the speed vector v f is the angle with the positive x axis; and ω f is the angular speed of the following unmanned sweeper; b is the distance of the center of mass from the rear axle of the vehicle; The expected position of the following unmanned sweeper is: where f is the following unmanned sweeper; l is the leading unmanned sweeper; x desired x coordinate for the following unmanned sweeper; y desired y coordinate for the following unmanned sweeper; desired heading angle for the following unmanned sweeper, considering that the leading unmanned sweeper always desires the same heading angle as the follower, i.e. always x l x coordinate of the leading unmanned sweeper; y l y coordinate of the leading unmanned sweeper; θ l heading angle of the leading unmanned sweeper; desired distance between the following unmanned sweeper and the leading unmanned sweeper; desired relative turning angle between the following unmanned sweeper and the leading unmanned sweeper; The error between the expected position and heading angle of the following unmanned sweeper and the actual position and heading angle is: In the formula, is the error of the x coordinate of the following unmanned sweeper; is the error of the y coordinate of the following unmanned sweeper; is the error of the θ coordinate of the following unmanned sweeper;x f is the x coordinate of the following unmanned sweeper; y f is the y coordinate of the following unmanned sweeper; The derivative of the position and heading angle error is: In the formula, ω l is the angular velocity of the piloted sweeper; Combined with the vehicle kinematic model of the following unmanned sweeper, the trajectory tracking error model of the unmanned sweeper formation is obtained as follows:

4. The method of claim 1, wherein the method further comprises: The specific method of step four is as follows: If the distance from the leading unmanned sweeper to the center line of the obstacle is d and the width of the leading unmanned sweeper is L0, if d > L0 / 2, it is considered that the sweeper formation can complete obstacle avoidance by shrinking the formation, and path planning is not needed, and the unmanned sweeper switches to the second formation; if d ≤ L0 / 2, it is considered that the unmanned sweeper formation cannot complete obstacle avoidance by changing the formation, and path planning is needed.

5. The method of claim 1, wherein the method further comprises: The specific method of step five is as follows: When the unmanned sweeper formation cannot complete obstacle avoidance by shrinking the formation, the leading sweeper sends an instruction to make the two following unmanned sweepers follow behind the leading unmanned sweeper, and the three unmanned sweepers are arranged in a row in the longitudinal direction; the leading unmanned sweeper generates a trajectory using the Hybrid A* algorithm; the leading unmanned sweeper leads the formation to travel along the planned trajectory until the obstacle avoidance is completed and the formation returns to the sweeping state.

6. A park unmanned sweeper formation sweeping system for implementing the park unmanned sweeper formation sweeping method of claim 1, characterized in that, It comprises: a coprocessor configured to calculate motion information of the unmanned sweeper according to the expected position and attitude transmitted by the host computer, generate a control instruction, receive sensor signals, and transmit sensing and positioning information to the host computer; a motion control module configured to receive the control instruction from the coprocessor, analyze the control instruction, and input a PWM control signal to a control execution module; a motion execution module configured to make the unmanned sweeper move according to the expected position and attitude, and feed back an encoder signal to the control module; a sensor module configured to sense surrounding obstacle and road information, position, calculate vehicle speed and acceleration; a host computer configured to perform environment sensing, motion planning, formation decision and multi-unmanned sweeper cooperative communication; The cleaning effect module is used for road cleaning and watering.

7. The garden unmanned sweeping vehicle formation sweeping system according to claim 6, characterized in that, The leading unmanned sweeper is provided with a coprocessor, a motion control module, a motion execution module, a sensor module, a cleaning effect module and an upper computer; the following unmanned sweeper is provided with a coprocessor, a motion control module, a motion execution module, a sensor module and a cleaning effect module.

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