Intelligent lawn mower control system and control method

Abstract

The present invention relates to the field of lawn mowers, and in particular to an intelligent lawn mower control system and control method, comprising: a first cutting blade arranged at the bottom of the lawn mower and a second cutting blade arranged on the side wall of the lawn mower, an information collection module for collecting geographic information and obstacle information of the area to be worked, information on lawn planting density, lawn soil moisture information, and temperature information, an information storage module for temporarily storing information collected by the information collection module and a mowing path map, a control module for determining work area attributes and corresponding mowing path strategies, determining whether the mowing height of the lawn mower meets preset standards based on a mowing evaluation value under a traversal mowing path strategy, and a control module for determining the operation strategy of the cutting blade module based on the type of work boundary under an obstacle-avoiding mowing path strategy, thereby realizing intelligent management of mowing and improving lawn trimming quality.

Description

Technical Field

[0001] The present invention relates to the field of lawn mowers, and in particular to an intelligent lawn mower control system and a control method thereof. Background Art

[0002] A smart lawn mower is a type of lawn mower that can automatically move, plan its mowing path, avoid obstacles, and charge itself. It's suitable for lawn mowing and maintenance in homes, gardens, public green spaces, and other places, significantly reducing manual labor and improving work efficiency.

[0003] Chinese Patent Publication No. CN111492784B discloses an adaptive multi-stage obstacle detection method for intelligent lawn mowers in complex terrain. The method first adaptively identifies the current terrain and calculates the drive wheel motor current threshold corresponding to the terrain. A current threshold-based method is then used as the first detection stage. If the real-time current fails this detection stage, a second detection stage based on the drive wheel speed increase rate is initiated. Finally, the presence of an obstacle is determined by combining the detection results from each stage. This technical solution lacks intelligent means for trimming obstacles and the surrounding lawn, making it ineffective for effectively trimming obstacles and the surrounding lawn. Summary of the Invention

[0004] To this end, the present invention provides an intelligent lawn mower control system and a control method thereof, so as to overcome the problem in the prior art that obstacles and the lawns around them cannot be effectively trimmed.

[0005] To achieve the above objectives, the present invention provides an intelligent lawn mower control system, comprising a power supply module, a travel module, and further comprising:

[0006] a cutting blade module comprising a first cutting blade disposed at the bottom of the mower and a second cutting blade disposed on a side wall of the mower, wherein the first cutting blade is telescopically downward along the mower and the second cutting blade is telescopically outward along the center of the mower;

[0007] The information collection module includes a first collection unit disposed above the lawn mower for collecting geographic information and obstacle information of the area to be operated, a second collection unit disposed above the lawn mower for collecting information on lawn planting density in the area to be operated, a third collection unit disposed below the lawn mower for collecting information on lawn soil moisture in the area to be operated, and a fourth collection unit for collecting temperature information of the area to be operated;

[0008] An information storage module, connected to the information acquisition module, comprising a first storage unit for temporarily storing information acquired by the information acquisition module and a second storage unit for storing a mowing path map;

[0009] a control module, which is respectively connected to the information acquisition module, the information storage module, the cutter module, the power supply module and the walking module, and is used to determine the attributes of the working area and the corresponding mowing path strategy according to the working boundary, the mowing path strategy including the traversal mowing path strategy and the obstacle avoidance mowing path strategy, and is used to determine whether the cutting height of the mower meets the preset standard based on the cutting evaluation value under the traversal mowing path strategy, and is used to determine the operation strategy of the cutter module based on the working boundary type under the obstacle avoidance mowing path strategy.

[0010] Furthermore, the control module determines the mowing path strategy of the lawn mower according to the attributes of the working area, wherein:

[0011] If the working area is an obstacle-free area, determining that the lawn mower uses a traversal mowing path strategy;

[0012] If the working area is an obstacle area, it is determined that the lawn mower uses an obstacle avoidance mowing path strategy.

[0013] Furthermore, the working area attributes are determined based on the working boundary, wherein the working area within the working boundary is marked as an obstacle area, and the working area outside the working boundary is marked as an obstacle-free area;

[0014] The operation boundary is a closed loop.

[0015] Furthermore, the operation boundary is determined based on the obstacle facade boundary projection contour, wherein:

[0016] If the operation boundary is an upwardly open type based on the projection contour of the obstacle's vertical boundary, the projection of the parallel contour of the obstacle's maximum cross-sectional contour corresponding to the preset height above the ground at a preset distance on the ground is used as the operation boundary of the obstacle, and is recorded as the first operation boundary;

[0017] If the working boundary is upwardly consistent or upwardly convergent based on the projection contour of the obstacle's facade boundary, the parallel contour of the cross-sectional contour of the obstacle in contact with the ground at a preset distance is used as the working boundary of the obstacle and is recorded as the second working boundary.

[0018] Furthermore, the control module determines whether the cutting height of the mower meets the preset standard based on the cutting evaluation value under the traversal mowing path strategy, wherein:

[0019] If the stubble evaluation value is less than a first preset stubble evaluation value, it is determined that the stubble height of the lawn mower does not meet a preset standard, and the stubble height is increased according to the difference between the first preset stubble evaluation value and the stubble evaluation value;

[0020] If the stubble evaluation value is greater than or equal to the first preset stubble evaluation value and less than the second preset stubble evaluation value, it is determined that the stubble height of the lawn mower meets the preset standard and the lawn mowing operation in the barrier-free area is completed according to the current stubble height;

[0021] If the stubble evaluation value is greater than or equal to the second preset stubble evaluation value, it is determined that the stubble height of the lawn mower does not meet the preset standard, and the stubble height is reduced according to the difference between the stubble evaluation value and the second preset stubble evaluation value;

[0022] The stubble cutting evaluation value is determined based on the lawn planting density and the lawn soil moisture.

[0023] Furthermore, the increase amplitude of the stubble height is positively correlated with the evaluation value difference, wherein the evaluation value difference is the difference between a first preset stubble evaluation value and the stubble evaluation value.

[0024] Furthermore, the control module corrects the increase in the cutting height in response to the temperature being greater than a preset temperature threshold.

[0025] Furthermore, the control module determines the operation strategy of the cutter module based on the type of the operation boundary under the obstacle-avoiding mowing path strategy;

[0026] If the operation boundary is the first operation boundary, the second cutting blade is used to complete the mowing operation in the obstacle area;

[0027] If the operation boundary is the second operation boundary, the first cutting blade is used to complete the mowing operation in the obstacle area;

[0028] The extended length of the second cutting knife is positively correlated with the perimeter of the maximum cross-sectional profile of the obstacle.

[0029] Furthermore, the control module corrects the preset distance between the maximum cross-sectional profile of the obstacle and the parallel profile in response to the coincidence between the image of the current area to be operated and the image of the previous area to be operated being less than a preset coincidence.

[0030] On the other hand, the present invention also provides a control method for an intelligent lawn mower, comprising:

[0031] Step S1, collecting information of the area to be operated, including geographical information, obstacle information, lawn planting density, lawn soil moisture information and temperature information;

[0032] Step S2, determining the operation boundary based on the obstacle facade boundary projection outline;

[0033] Step S3, determining the obstacle area and the obstacle-free area based on the operation boundary;

[0034] Step S4, determining a mowing path strategy for the lawn mower based on the area type, including an obstacle avoidance mowing path strategy and a traversal mowing path strategy;

[0035] Step S5, determining whether the cutting height of the lawn mower meets a preset standard based on the cutting evaluation value under the traversal mowing path strategy;

[0036] Step S6: determining the operation strategy of the cutter module based on the type of the operation boundary under the obstacle avoidance mowing path strategy.

[0037] Compared with the prior art, the beneficial effect of the present invention lies in: the present invention uses a first cutting blade arranged at the bottom of the lawn mower and a second cutting blade arranged on the side wall of the lawn mower, and collects information through an information collection module and determines the working area attributes and the corresponding mowing path strategy of the lawn according to the obstacle information based on the collected information, especially determines the operation strategy of the cutting blade module according to the type of working boundary, thereby intelligently and effectively trimming the obstacle and the lawn around it. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of the intelligent lawn mower control system according to an embodiment of the present invention;

[0039] Figure 2 This is a flow chart of determining an operation boundary based on an obstacle facade boundary projection outline according to an embodiment of the present invention;

[0040] Figure 3 A flow chart of determining whether the cutting height of the lawn mower meets a preset standard under the traversal mowing path strategy according to an embodiment of the present invention;

[0041] Figure 4 This is a flow chart of a control method for an intelligent lawn mower according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic structural diagram of a cutter module according to an embodiment of the present invention;

[0043] In the figure: 1, lawn mower; 11, second cutting blade; 12, first cutting blade. DETAILED DESCRIPTION

[0044] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0045] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] See also Figure 1-Figure 5As shown, they are respectively a schematic diagram of the structure of the intelligent lawn mower control system according to an embodiment of the present invention; a flow chart of determining the working boundary based on the projection contour of the obstacle facade boundary according to an embodiment of the present invention; a flow chart of determining whether the cutting height of the lawn mower meets the preset standard under the traversal mowing path strategy according to an embodiment of the present invention; a flow chart of the control method of the intelligent lawn mower according to an embodiment of the present invention; and a schematic diagram of the structure of the cutter module according to an embodiment of the present invention.

[0047] On the one hand, the intelligent lawn mower control system according to the embodiment of the present invention includes: a power supply module, a travel module, and further includes:

[0048] A cutting blade module, comprising a first cutting blade 12 provided at the bottom of the mower 1 and a second cutting blade 11 provided on a side wall of the mower, wherein the first cutting blade 12 is telescopically downward along the mower, and the second cutting blade 11 is telescopically outward along the center of the mower;

[0049] The information collection module includes a first collection unit disposed above the lawn mower for collecting geographic information and obstacle information of the area to be operated, a second collection unit disposed above the lawn mower for collecting information on lawn planting density in the area to be operated, a third collection unit disposed below the lawn mower for collecting information on lawn soil moisture in the area to be operated, and a fourth collection unit for collecting temperature information of the area to be operated;

[0050] An information storage module, connected to the information acquisition module, comprising a first storage unit for temporarily storing information acquired by the information acquisition module and a second storage unit for storing a mowing path map;

[0051] a control module, which is respectively connected to the information acquisition module, the information storage module, the cutter module, the power supply module and the walking module, and is used to determine the attributes of the working area and the corresponding mowing path strategy according to the working boundary, the mowing path strategy including the traversal mowing path strategy and the obstacle avoidance mowing path strategy, and is used to determine whether the cutting height of the mower meets the preset standard based on the cutting evaluation value under the traversal mowing path strategy, and is used to determine the operation strategy of the cutter module based on the working boundary type under the obstacle avoidance mowing path strategy.

[0052] Specifically, the first cutting knife can be extended and retracted vertically downward along the lawn mower and the second cutting knife can be extended and retracted outward along the center of the lawn mower by moving the guide rail, and the rotation of the first cutting knife and the second cutting knife can be achieved by a drive motor.

[0053] Specifically, the first acquisition unit, such as a laser radar or an industrial camera, is not specifically limited and only needs to be able to collect geographic information and obstacle information of the area to be operated.

[0054] Specifically, the second acquisition unit, such as an industrial camera, is not specifically limited and is used to generate the lawn planting density of the area to be operated by acquiring images.

[0055] Specifically, the third collection unit, such as a soil moisture sensor, collects lawn soil moisture information in any specific form, such as collecting soil moisture at the surface or 1 cm below the surface. The depth is not limited and can be set according to actual applications.

[0056] Specifically, the fourth acquisition unit, such as a temperature sensor (not specifically limited), is used to acquire temperature information of the area to be operated.

[0057] Specifically, the control module, such as a CPU, is not specifically limited and only needs to output corresponding calculation results based on input information.

[0058] Specifically, the control module determines the mowing path strategy of the lawn mower according to the attributes of the work area, wherein:

[0059] If the working area is an obstacle-free area, determining that the lawn mower uses a traversal mowing path strategy;

[0060] If the working area is an obstacle area, it is determined that the lawn mower uses an obstacle avoidance mowing path strategy.

[0061] Specifically, the working area attributes are determined based on the working boundary, wherein the working area within the working boundary is marked as an obstacle area, and the working area outside the working boundary is marked as an obstacle-free area;

[0062] The operation boundary is a closed loop.

[0063] Specifically, the operation boundary is determined based on the obstacle facade boundary projection contour, wherein:

[0064] If the working boundary is upwardly open based on the projection contour of the obstacle's vertical boundary, the projection of the parallel contour of the obstacle's maximum cross-sectional contour corresponding to a preset height of 1m above the ground at a preset distance of 0.5m on the ground is used as the working boundary of the obstacle and is recorded as the first working boundary;

[0065] If the working boundary is upwardly consistent or upwardly convergent based on the projection contour of the obstacle's facade boundary, the parallel contour of the cross-sectional contour of the obstacle in contact with the ground at a preset distance is used as the working boundary of the obstacle and is recorded as the second working boundary.

[0066] It can be understood that the upward open type means that the maximum cross-sectional profile of the obstacle becomes larger as the upward height increases; the upward consistent type means that the maximum cross-sectional profile of the obstacle remains unchanged as the upward height increases; and the upward convergent type means that the maximum cross-sectional profile of the obstacle becomes smaller as the upward height increases.

[0067] Specifically, the control module determines whether the stubble height of the mower meets the preset standard based on the stubble evaluation value under the traversal mowing path strategy, wherein:

[0068] If the stubble evaluation value is less than a first preset stubble evaluation value of 0.94, it is determined that the stubble height of the lawn mower does not meet the preset standard, and the stubble height is increased according to the difference between the first preset stubble evaluation value and the stubble evaluation value;

[0069] If the stubble evaluation value is greater than or equal to the first preset stubble evaluation value and less than the second preset stubble evaluation value of 1.32, it is determined that the stubble height of the lawn mower meets the preset standard and the lawn mowing operation in the barrier-free area is completed according to the current stubble height;

[0070] If the stubble evaluation value is greater than or equal to the second preset stubble evaluation value, it is determined that the stubble height of the lawn mower does not meet the preset standard, and the stubble height is reduced according to the difference between the stubble evaluation value and the second preset stubble evaluation value;

[0071] The stubble evaluation value is determined based on the lawn planting density and the lawn soil moisture. The calculation formula of the stubble evaluation value is as follows:

[0072]

[0073] Among them, G is the stubble evaluation value, α is the density evaluation coefficient, set α = 0.54, β is the humidity evaluation coefficient, set β = 0.37, ρ is the lawn planting density, its unit is the number of grass plants planted per unit area, ρ0 is the density threshold, set ρ0 = 500 plants / m 2 , h is the lawn soil moisture, its unit is the weight percentage of water in the soil, h0 is the humidity threshold, set h0 = 28%.

[0074] Specifically, the increase in the stubble height is positively correlated with the evaluation value difference, wherein the evaluation value difference is the difference between the first preset stubble evaluation value and the stubble evaluation value, wherein the positive correlation is, for example, a linear positive correlation or a nonlinear positive correlation, which is not specifically limited, and the slope of the linear positive correlation is not limited either, as long as the greater the evaluation value difference, the greater the increase in the stubble height.

[0075] Specifically, the control module corrects the increase in the cutting height in response to the temperature being greater than a preset temperature threshold of 25°C, wherein:

[0076] The first height correction method is that the control module uses a first preset height correction coefficient of 0.98 to reduce the increase in the cutting height; the first height correction method satisfies that the temperature difference is less than a first preset temperature difference of 1.5°C;

[0077] The second height correction method is that the control module uses a second preset height correction coefficient of 0.95 to reduce the increase in the cutting height; the second height correction method satisfies that the temperature difference is greater than or equal to the first preset temperature difference and less than a second preset temperature difference of 3.8°C;

[0078] The third height correction method is that the control module uses a third preset height correction coefficient of 0.91 to reduce the increase in the cutting height; the second height correction method satisfies that the temperature difference is greater than or equal to the second preset temperature difference;

[0079] The temperature difference is the difference between the temperature and a preset temperature threshold.

[0080] Specifically, the control module determines the operation strategy of the cutter module based on the type of the operation boundary under the obstacle avoidance mowing path strategy;

[0081] If the operation boundary is the first operation boundary, the second cutting blade is used to complete the mowing operation in the obstacle area;

[0082] If the operation boundary is the second operation boundary, the first cutting blade is used to complete the mowing operation in the obstacle area;

[0083] The extended length of the second cutting knife is positively correlated with the perimeter of the maximum cross-sectional contour of the obstacle. It can be understood that the larger the perimeter of the maximum cross-sectional contour of the obstacle is, the larger the extended length of the second cutting knife is.

[0084] Specifically, the control module corrects the preset distance between the maximum cross-sectional profile of the obstacle and the parallel profile in response to the coincidence between the image of the current area to be operated and the image of the previous area to be operated being less than a preset coincidence of 95%, wherein:

[0085] If the overlap difference is less than the first preset overlap difference of 5.00%, the control module increases the preset distance to a corresponding value using a first preset distance correction coefficient of 1.12;

[0086] If the overlap difference is greater than or equal to the first preset overlap difference and less than the second preset overlap difference of 11.5%, the control module increases the preset distance to a corresponding value using a second preset distance correction coefficient of 1.25;

[0087] If the overlap difference is greater than or equal to the second preset overlap difference, the control module increases the preset distance to a corresponding value using a third preset distance correction coefficient of 1.57;

[0088] The overlap difference is the difference between a preset overlap and the overlap.

[0089] On the other hand, the present invention also provides a control method for an intelligent lawn mower, comprising:

[0090] Step S1, collecting information of the area to be operated, including geographical information, obstacle information, lawn planting density, lawn soil moisture information and temperature information;

[0091] Step S2, determining the operation boundary based on the obstacle facade boundary projection outline;

[0092] Step S3, determining the obstacle area and the obstacle-free area based on the operation boundary;

[0093] Step S4, determining a mowing path strategy for the lawn mower based on the area type, including an obstacle avoidance mowing path strategy and a traversal mowing path strategy;

[0094] Step S5, determining whether the cutting height of the lawn mower meets a preset standard based on the cutting evaluation value under the traversal mowing path strategy;

[0095] Step S6: determining the operation strategy of the cutter module based on the type of the operation boundary under the obstacle avoidance mowing path strategy.

[0096] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0097] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An intelligent lawn mower control system, including a power supply module and a travel module, characterized in that: Also includes: a cutting blade module comprising a first cutting blade disposed at the bottom of the mower and a second cutting blade disposed on a side wall of the mower, wherein the first cutting blade is telescopically downward along the mower and the second cutting blade is telescopically outward along the center of the mower; The information collection module includes a first collection unit disposed above the lawn mower for collecting geographic information and obstacle information of the area to be operated, a second collection unit disposed above the lawn mower for collecting information on lawn planting density in the area to be operated, a third collection unit disposed below the lawn mower for collecting information on lawn soil moisture in the area to be operated, and a fourth collection unit for collecting temperature information of the area to be operated; An information storage module, connected to the information acquisition module, comprising a first storage unit for temporarily storing information acquired by the information acquisition module and a second storage unit for storing a mowing path map; a control module, connected to the information acquisition module, the information storage module, the cutter module, the power supply module, and the travel module, respectively, for determining attributes of an operating area and a corresponding mowing path strategy based on an operating boundary, wherein the mowing path strategy includes a traversal mowing path strategy and an obstacle avoidance mowing path strategy, for determining whether a stubble height of the mower meets a preset standard based on a stubble evaluation value under the traversal mowing path strategy, and for determining an operating strategy of the cutter module based on the type of operating boundary under the obstacle avoidance mowing path strategy; The control module determines the mowing path strategy of the lawn mower according to the attributes of the working area, wherein: If the working area is an obstacle-free area, determining that the lawn mower uses a traversal mowing path strategy; If the working area is an obstacle area, determining that the lawn mower uses an obstacle avoidance mowing path strategy; The working area attributes are determined based on the working boundary, wherein the working area within the working boundary is marked as an obstacle area, and the working area outside the working boundary is marked as an obstacle-free area; The operation boundary is a closed loop; The operation boundary is determined based on the obstacle facade boundary projection outline, wherein, If the operation boundary is an upwardly open type based on the projection contour of the obstacle's vertical boundary, the projection of the parallel contour of the obstacle's maximum cross-sectional contour corresponding to the preset height above the ground at a preset distance on the ground is used as the operation boundary of the obstacle, and is recorded as the first operation boundary; If the operation boundary is an upwardly consistent type or an upwardly convergent type based on the projection contour of the obstacle elevation boundary, a parallel contour of the cross-sectional contour of the obstacle in contact with the ground at a preset distance is used as the operation boundary of the obstacle, and is recorded as the second operation boundary; The upward open type means that the maximum cross-sectional profile of the obstacle increases with the increase of the upward height; the upward consistent type means that the maximum cross-sectional profile of the obstacle remains unchanged with the increase of the upward height; the upward convergent type means that the maximum cross-sectional profile of the obstacle decreases with the increase of the upward height; The control module determines the operation strategy of the cutter module based on the type of the operation boundary under the obstacle avoidance mowing path strategy; If the operation boundary is the first operation boundary, the second cutting blade is used to complete the mowing operation in the obstacle area; If the operation boundary is the second operation boundary, the first cutting blade is used to complete the mowing operation in the obstacle area; wherein the extension length of the second cutting knife is positively correlated with the perimeter of the maximum cross-sectional profile of the obstacle; The control module corrects the preset distance between the maximum cross-sectional profile of the obstacle and the parallel profile in response to a coincidence between the image of the current area to be operated and the image of the previous area to be operated being less than a preset coincidence.

2. The intelligent lawn mower control system according to claim 1, characterized in that: The control module determines whether the mowing height of the lawn mower meets the preset standard based on the mowing evaluation value under the traversal mowing path strategy, wherein: If the stubble evaluation value is less than a first preset stubble evaluation value, it is determined that the stubble height of the lawn mower does not meet a preset standard, and the stubble height is increased according to the difference between the first preset stubble evaluation value and the stubble evaluation value; If the stubble evaluation value is greater than or equal to the first preset stubble evaluation value and less than the second preset stubble evaluation value, it is determined that the stubble height of the lawn mower meets the preset standard and the lawn mowing operation in the barrier-free area is completed according to the current stubble height; If the stubble evaluation value is greater than or equal to the second preset stubble evaluation value, it is determined that the stubble height of the lawn mower does not meet the preset standard, and the stubble height is reduced according to the difference between the stubble evaluation value and the second preset stubble evaluation value; The stubble cutting evaluation value is determined based on the lawn planting density and the lawn soil moisture.

3. The intelligent lawn mower control system according to claim 2, characterized in that: The increase range of the stubble height is positively correlated with the evaluation value difference, wherein the evaluation value difference is the difference between a first preset stubble evaluation value and the stubble evaluation value.

4. The intelligent lawn mower control system according to claim 3, characterized in that: The control module modifies the increase in cutting height in response to the temperature being greater than a preset temperature threshold.

5. A control method for an intelligent lawn mower control system according to any one of claims 1 to 4, characterized in that: include: Step S1, collecting information of the area to be operated, including geographical information, obstacle information, lawn planting density, lawn soil moisture information and temperature information; Step S2, determining the operation boundary based on the obstacle facade boundary projection outline; Step S3, determining the obstacle area and the obstacle-free area based on the operation boundary; Step S4, determining a mowing path strategy for the lawn mower based on the area type, including an obstacle avoidance mowing path strategy and a traversal mowing path strategy; Step S5, determining whether the cutting height of the lawn mower meets a preset standard based on the cutting evaluation value under the traversal mowing path strategy; Step S6: determining the operation strategy of the cutter module based on the type of the operation boundary under the obstacle avoidance mowing path strategy.

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