Boundary-free mower and control method for avoiding out-of-boundary and escape signal shielding

Abstract

The invention provides a boundless mower and a control method for avoiding out-of-bound and escape signal shielding. According to the parameters of the mower, the working area is divided into the inner layer and the outer layer on the premise that it is guaranteed that the mower body does not leave the boundary, the mower is arranged to conduct traversal operation on the outer layer along the annular path, boundary crossing of the mower body caused by frequent steering of the mower is avoided, and operation is conducted on the inner layer through the broken line-shaped traversal path to guarantee the operation effect. The path planning algorithm provided by the invention solves the unexpected situation that the boundless self-walking robot leaves the boundaries and the problem that the boundless self-walking robot cannot walk out of the signal shielding area by itself originally. And the success rate of fault-free operation of the self-walking equipment is improved. And the satisfaction degree of a user to a product during use is improved.

Description

Technical Field

[0001] The present application relates to the technical field of automated garden tools, and in particular to a control method for a borderless lawn mower to avoid going out of bounds and escaping signal shielding. Background Art

[0002] Borderless smart lawn mowers are usually based on GPS / Beidou positioning technology, RTK assisted positioning algorithm, wireless communication and IMU sensor detection technology, etc., which are integrated into a self-propelled robot to provide judgment for its walking decision. Its navigation process generally obtains the reference position information through the base station, and then exchanges the position information with the base station through wireless communication according to the positioning module of the self-propelled robot itself, and finally calculates whether it is in the user's planned working area through the algorithm, and then switches the working state and running path of the lawn mower.

[0003] However, in actual operation, borderless lawn mowers usually have the following technical problems: First, the working area of ​​the borderless self-propelled robot is actually a closed area planned by the user based on the GPS / Beidou positioning information, which only cancels the physical boundary line in the traditional sense. Under this control strategy, it is necessary to store a virtual boundary line corresponding to the lawn position in the internal storage medium of the lawn mower. When the machine mows the lawn for the first time, it will cut a circle along the boundary line and identify the boundary line. In the subsequent traversal mowing process, when there are tall buildings or other tall trees around the working area, the lawn mower often has a deviation from the actual position of the machine due to weak GPS / Beidou signals, signal reflection, etc., and then the system drives the lawn mower incorrectly due to the deviation, causing the machine to walk out of the working area. Second, in many cases, some trees are planted at intervals on the edge of the lawn. When the machine walks under a larger tree, the GPS / Beidou signal may be lost, causing the machine to not work properly. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present application provides a control method for a borderless lawn mower to avoid going out of bounds and escaping signal obstruction, and aims to solve the problems of a borderless intelligent lawn mower robot going out of bounds and having its positioning signal blocked. The present application can overcome the above problems by adjusting the walking path of the lawn mower, thereby improving the success rate of trouble-free operation of the self-propelled equipment and improving user satisfaction with the product during use. The present application specifically adopts the following technical solutions.

[0005] Firstly, to achieve the above-mentioned purpose, a control method for avoiding out-of-bounds and escape signal shielding is proposed, wherein the steps include: dividing the working area of ​​the lawn mower into a first area and a second area which are nested with each other according to a first parameter of the lawn mower, wherein the second area is surrounded by the first area, and the first area is located between the boundary line of the second area and the working area; firstly driving the lawn mower to traverse the operation in the first area, and then driving the lawn mower inward into the second area to traverse the operation; wherein the running path of the lawn mower traversing the operation in the first area is arranged in a ring along the boundary line of the working area.

[0006] Optionally, a control method for avoiding out-of-bounds and escaping signal obstruction as described in any of the above, wherein, during the traversal operation in the first area, if the first positioning signal of the lawn mower is lost, its navigation mode is switched, and the operation continues for the first safety period according to the second navigation signal; during this period, if the first positioning signal is restored within the first safety period, the lawn mower is switched to restore the original navigation mode; if the first positioning signal is not restored within the first safety period, the positioning abnormality point at this time is recorded, and the lawn mower is switched to traversal operation in the second area.

[0007] Optionally, a control method for avoiding out-of-bounds and escaping signal obstruction as described in any of the above, wherein, during the process of the lawn mower turning to traverse the second area, if the first positioning signal is restored within the second safety period, the lawn mower is switched to resume the original navigation mode based on the first positioning signal and continue to operate, and when the lawn mower approaches the position of the original positioning abnormality point, the lawn mower is driven to continue to operate according to the original traversal path before the first positioning signal was lost; if the first positioning signal is not restored within the second safety period, the positioning abnormality point at this time continues to be recorded, and the lawn mower is switched to traverse the second area.

[0008] Optionally, in a control method for avoiding out-of-bounds and escaping signal obstruction as described above, the first parameter includes: body length, body width, minimum turning radius, and mowing width of the lawn mower.

[0009] Optionally, a control method for avoiding out-of-bounds and escaping signal obstruction as described above, wherein the width of the first area is not less than the first parameter; the running path of the lawn mower traversal operation in the first area is: several layers of mutually nested circular paths arranged parallel to the boundary line of the working area, each circle of the circular path completely surrounds the second area, and each circle of the circular path is inward toward the second area one by one.

[0010] Optionally, a control method for avoiding out-of-bounds and escaping signal obstruction as described above, wherein the first safety period is shorter than the second safety period; the lawn mower continues to move forward relying on IMU inertial navigation during the first safety period, and only operates within the second area during the second safety period.

[0011] Optionally, in any of the control methods for avoiding out-of-bounds and escaping signal obstruction as described above, the running path of the lawn mower traversing the second area is parallel to the boundary line of the area, and is an interlaced straight line or broken line.

[0012] At the same time, in order to achieve the above-mentioned purpose, the present application also provides a borderless lawn mower, which includes: a navigation system, which is provided with two sets, and determines the current position of the lawn mower for positioning and navigation based on different signals; a path planning module, which divides the working area of ​​the lawn mower into a first area and a second area that are nested with each other according to the first parameter of the lawn mower, wherein the second area is surrounded by the first area, and the first area is located between the boundary line of the second area and the working area, and the running path of the lawn mower in the first area is set as a ring along the boundary line of the working area, and the running path of the lawn mower in the second area is set as a staggered straight line or broken line; a control unit, which first drives the lawn mower to traverse the operation in the first area according to the running path determined by the path planning module, and then drives the lawn mower to enter the second area inward to traverse the operation; during this period, if the positioning signal of the lawn mower is lost, the navigation system is switched to run for a safe period, and if the positioning signal is restored within the safe period, it is switched back to the original navigation system to continue running; if the positioning signal is not restored within the safe period, the positioning abnormal point at this time is recorded, and the lawn mower is switched to turn to the second area for traversal operation.

[0013] Optionally, in any of the above described borderless lawn mowers, the first navigation system is a GPS positioning system; and the second navigation system is an IMU inertial navigation system. Beneficial Effects

[0014] The control method for the borderless lawn mower, avoiding going out of bounds and escaping signal blocking provided by the present application divides the working area into two layers, inner and outer, based on the parameters of the lawn mower itself, while ensuring that the fuselage will not go out of bounds. The lawn mower is set to traverse along a circular path in the outer layer to avoid frequent turning and causing the fuselage to go out of bounds, while the inner layer maintains a broken line traversal path to ensure the working effect. The path planning algorithm of the present invention solves the unexpected situation of the borderless self-propelled robot going out of bounds and the original problem of being unable to walk out of the signal blocking area by itself. It improves the success rate of trouble-free operation of self-propelled equipment. It improves user satisfaction with the product during use.

[0015] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings: Figure 1 is a schematic diagram of the working environment of the lawn mower system of the present application; Figure 2 is a schematic diagram of the traversal method of the lawn mower of the present application in different working areas; In the figure, 1 represents a base station; 2 represents a lawn mower; 3 represents a boundary line; 3' represents a boundary line of the second area; 4 represents a running path of the lawn mower in the first area; and 5 represents a running path of the lawn mower in the second area. DETAILED DESCRIPTION

[0017] In order to make the purpose and technical solution of the embodiment of the present application clearer, the technical solution of the embodiment of the present application will be clearly and completely described in conjunction with the drawings of the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, not all of the embodiments. Based on the described embodiment of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0019] The meaning of "inside" and "outside" in this application refers to the direction pointing to the inner center of the working area relative to the working area itself, and the opposite direction is outside; it is not a specific limitation on the device mechanism of this application.

[0020] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0021] Figure 1 According to a control method for avoiding out-of-bounds and escaping signal shielding according to the present application, first, the outer boundary line 3 of the working area is determined according to the coordinate range circled by the user on the map, or the outer boundary line 3 of the working area is determined according to the path along the boundary line directed by the user, or, in some more advanced models, an image processing algorithm is used to identify the grass range in the working area image and automatically generate the outer boundary line 3 of the working area.

[0022] Then, the present application can slightly expand the first parameter of the lawn mower, such as the body length, body width, minimum turning radius, mowing width and other data of the lawn mower, as a parameter indicator of the width of the buffer zone to avoid the problem of the self-propelled robot going out of bounds, thereby dividing the working area of ​​the lawn mower into Figure 1 The first area and the second area are nested with each other. Figure 1 The inside of the gray box is the second area, and its boundary line is surrounded by the first area. The first area is a "mouth"-shaped area with a buffer zone width between the boundary line 3 of the second area and the working area; After determining the two areas, the lawn mower can be driven to traverse the first area first, and then driven to traverse the second area inwards; During this period, in order to ensure that the body of the lawn mower will not go out of bounds due to turning or avoiding obstacles during the traversal operation in the first area, we arrange the running path of the lawn mower in this area as a ring structure that is gradually retracted along the boundary line of the working area. During the operation, the lawn mower first runs along the boundary line 3 for a circle, and then slightly deviates a certain distance in the inner direction of the second area, and continues to circle the first area in a direction parallel to the previous circular route. Then, it continues to deviate inward layer by layer and runs along a similar circular route until the lawn mower reaches the boundary line 3' of the second area, that is, the traversal operation of the first area is completed. In this process, since the equipment only turns at the corner position of the working area, and due to the layout of the working area, the turning angle of the corner area is usually close to 90° or rarely appears within a narrow angle of 10°, the lawn mower does not need to turn around during the turning process, but can achieve the turning through the speed difference between the inner and outer walking wheels. Such a turning process can well compare the problem of the robot body part structure out of bounds caused by the original serpentine traversal path turning around at the edge of each side of the working area.

[0023] After the robot completes the circular traversal of the outer area, it can turn inward from the boundary line 3' of the second area to reach the second area, and then use the traditional traversal method to cut the lawn in the second area. Figure 2 As shown, in the second area, the traversal path of the mower can be set to be staggered straight lines or broken lines parallel to the direction of the boundary line of the area. In this area, after the mower runs in a direction parallel to the boundary line of one side of the second area and reaches the position of the boundary line of the other side of the area, it turns around directly, and then deviates a certain width along the original path to perform the next operation, until the device reaches the end of the second area, the traversal and mowing of the second area can be completed.

[0024] In some implementations, in order to improve the mowing effect, the present application can complete the horizontal traversal operation in the second area, and then perform a round of longitudinal traversal mowing operation in a similar traversal manner to ensure that the intersections between the horizontal mowing tracks can be cut, so as to achieve a smoother and neater mowing effect. The longitudinal traversal mowing operation process is similar to the horizontal one: the mower is driven to run along a boundary line of the second area to the adjacent boundary line, and then turns around at the boundary line and deviates a certain distance, usually the width of a blade disc, and then runs in a direction parallel to the previous boundary line to the boundary line on the opposite side of the fuselage, and then continues to perform the steps of turning around, deviating, and mowing reciprocally.

[0025] Reference Figure 1 Since the periphery of the lawn mower's working area is usually planted with relatively tall trees, the positioning signal of the vehicle body will be lost to a certain extent during its traversal operation. In order to avoid the loss of positioning signals causing the equipment to fail to operate correctly and affect the mowing effect and operation safety, the present application also preferably sets two navigation systems in the borderless lawn mower, so that the two systems can determine the current position of the lawn mower based on different signals for positioning and navigation.

[0026] In the device, in order to realize the path planning of the above-mentioned inner and outer layers with different traversal modes, the present application also preferably sets the path planning module in the lawn mower to: according to the first parameter of the lawn mower, the working area of ​​the lawn mower is divided into a first area and a second area which are nested with each other, and the first area is set as a ring or square structure surrounding the second area, and the first area is used to ensure that the device will not cross the outer boundary line of the entire working area when turning around at the boundary line of the second area, and by setting the running path of the lawn mower in the first area as a ring along the boundary line of the working area, the number of U-turns and turns of the device in the outer layer of the working area is reduced to avoid the risk of crossing the boundary, and the running path of the lawn mower in the second area is set as staggered straight lines or broken lines to ensure the working effect.

[0027] The control unit of the lawn mower first drives the lawn mower to traverse the first area according to the operation path determined by the path planning module, and then drives the lawn mower to traverse the second area inward. During the entire operation period, the lawn mower performs positioning and navigation in one way by default; If the lawn mower's positioning signal is lost, it will switch to a second navigation system that relies on another signal and run for a safe period. If the positioning signal is restored within the safe period, it will switch back to the original navigation system and continue to run. If the positioning signal is not restored within the safe period, the positioning abnormality point at this time will be recorded, and the lawn mower will be switched to traverse the second area.

[0028] In order to ensure the accuracy of positioning and guidance and enable the two navigation systems to complement each other, this application generally sets the first navigation system of the device to be the GPS positioning system; and sets the second navigation system of the device to be the IMU inertial navigation system. Therefore, when the device is traversing in the first area outside the working area, if the GPS positioning system signal of the lawn mower is blocked by a large tree and lost, its navigation mode is switched and the first safety period is continued according to the navigation signal of the IMU inertial navigation system; During this period, if the first positioning signal is restored within the first safety period, the lawn mower is switched to resume the original navigation mode; if the first positioning signal is not restored within the first safety period, the positioning abnormal point at this time is recorded, and the lawn mower is switched to traverse the second area.

[0029] When the mower turns to the second area and traverses the operation, If the first positioning signal can be restored within the second safety period, the lawn mower can be switched to resume the original navigation mode based on the first positioning signal and continue to run along the horizontal or vertical track when the signal is restored, and when the lawn mower approaches the position of the positioning abnormal point originally located in the first area, the lawn mower is driven to return to the original circular track of the first area, so that the device continues to run according to the original traversal path before the first positioning signal is lost; If the first positioning signal is not restored within the second safety period, the abnormal positioning point at this time can continue to be recorded, and the lawn mower can be switched to traverse the second area.

[0030] Therefore, the system can navigate by inertial navigation when the GPS signal is blocked until the positioning signal is restored. When the signal cannot be restored, in order to avoid deviation of pipeline guidance, the operating area of ​​the equipment can be switched in time, and the equipment can be transferred to a second area away from the blockage, and the operation can be carried out in a safer location waiting for the GPS signal to be restored.

[0031] In the above process, since GPS signal navigation is more accurate, and the inertial navigation method will produce a certain offset due to the cumulative error of the sensor, and the equipment has higher accuracy requirements when operating in the first area, the equipment is more likely to encounter obstacles such as trees and people that need to be avoided outside the grass. Therefore, the present application preferably sets the first safety period to be smaller than the second safety period; the lawn mower is set to continue moving forward relying on IMU inertial navigation during the first safety period, and only operate within the second area during the second safety period.

[0032] The following is a detailed Figure 2 Take this as an example to explain the working process of this application in detail: 1. After the user draws the working area, the lawn mower system calculates the boundary line map according to the area enclosed by the user. The machine plans the path to mow along the boundary line. The machine shifts inward 10 cm every time it runs along the outermost boundary line 3. Since the length of the equipment body is 70 cm, after the machine has circled the path around the boundary line 10 times, it can be guaranteed that the lawn mower will not exceed the boundary line of the outermost circle no matter how it turns around in the inner circle. Therefore, the machine re-plans the working path for the inner circle of the working area, that is, the second area. Therefore, by running along the boundary line in the outer circle, the system greatly reduces the probability of the machine head running toward the boundary, thus avoiding the risk of the machine going out of bounds abnormally. A new working area is formed within 100 cm from the boundary line. In this working area, the machine normally traverses and mows using horizontal and vertical traversal algorithms.

[0033] 2. When the equipment is working, it is preferred to use GPS signals for positioning and navigation. When the machine walks under a big tree along the outer circle and the GPS signal is lost, the machine can be triggered to switch to IMU inertial navigation to continue moving forward. When running along the boundary line, we set the reliability of IMU to 10 seconds, that is, 0.3m / s*10s=3 meters. If the positioning signal is restored at this time, it will continue to run along the original path relying on the GPS signal; if the positioning is not restored, the point position information at this time is recorded as d1. At this time, in order to ensure safety, the machine will generally be driven to turn and run to the second area inside the boundary. Here, we set the IMU reliability in the second inner area to 2 minutes. If the positioning is restored within two minutes, it will continue to switch to the positioning guidance through the GPS signal to continue running. At this time, when the machine traverses the mowing process in the second inner area of ​​the boundary and returns to the point d1 near the record, the device can be driven from the inner circle to the outer circle d1 point according to the GPS guidance, and continue to restore the circular operation along the boundary line. If the positioning signal is lost again, and the device does not recover within 10 seconds of the IMU threshold, the lost position is recorded as d2, and the machine moves to the inner area to repeat the inner circle reliability process of 2 minutes. By recording the discrete positioning signal loss points, d3 d4 d5... dn, the machine can continue to repeat the above process and slowly complete the cutting of these discrete points.

[0034] The above is only an implementation method of the present application, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application.

Claims

1. A control method for avoiding out-of-bounds and escaping signal shielding, characterized in that the steps include: Dividing the working area of ​​the lawn mower into a first area and a second area which are mutually nested according to a first parameter of the lawn mower, wherein the second area is surrounded by the first area, and the first area is located between a boundary line of the second area and the working area; First, the lawn mower is driven to traverse the first area, and then the lawn mower is driven to enter the second area to traverse the second area; The running path of the lawn mower's traversal operation in the first area is arranged in a ring along the boundary line of the working area.

2. The control method for avoiding out-of-bounds and escaping signal shielding as claimed in claim 1, characterized in that: During the traversal operation in the first area, if the first positioning signal of the lawn mower is lost, the lawn mower switches its navigation mode and continues to operate during the first safety period according to the second navigation signal; During this period, If the first positioning signal is restored within the first safety period, the lawn mower is switched to restore the original navigation mode; If the first positioning signal is not restored within the first safety period, the abnormal positioning point at this time is recorded, and the lawn mower is switched to traverse the second area.

3. The control method for avoiding out-of-bounds and escaping signal shielding as claimed in claim 2, characterized in that: When the mower turns to the second area and traverses the operation, If the first positioning signal is restored within the second safety period, the lawn mower is switched to resume the original navigation mode based on the first positioning signal and continue to operate, and when the lawn mower approaches the position of the original positioning abnormal point, the lawn mower is driven to continue to operate according to the original traversal path before the first positioning signal is lost; If the first positioning signal is not restored within the second safety period, the abnormal positioning point at this time continues to be recorded, and the lawn mower is switched to traverse the second area.

4. The control method for avoiding out-of-bounds and escaping signal shielding as claimed in claim 1, characterized in that: The first parameters include: the body length, body width, minimum turning radius, and mowing width of the lawn mower.

5. The control method for avoiding out-of-bounds and escaping signal shielding as claimed in claim 5, characterized in that: The width of the first area is not less than a first parameter; The running path of the lawn mower traversing operation in the first area is: a plurality of layers of mutually nested circular paths arranged parallel to the boundary line of the working area, each circle of the circular path completely surrounds the second area, and each circle of the circular path gradually retracts inward toward the second area.

6. The control method for avoiding out-of-bounds and escaping signal shielding as described in claims 2-4, characterized in that: The first safety period is shorter than the second safety period; The lawn mower continues to move forward by relying on IMU inertial navigation during the first safety period, and only operates in the second area during the second safety period.

7. The control method for avoiding out-of-bounds and escaping signal shielding according to claim 1, characterized in that: The running path of the lawn mower traversing operation in the second area is parallel to the boundary line of the area, and is a staggered straight line or a broken line.

8. A borderless lawn mower, characterized in that: include: The navigation system has two sets, which are used to determine the current position of the lawn mower based on different signals for positioning and navigation; a path planning module, which divides the working area of ​​the lawn mower into a first area and a second area which are nested with each other according to a first parameter of the lawn mower, wherein the second area is surrounded by the first area, the first area is located between the boundary line of the second area and the working area, and sets the running path of the lawn mower in the first area to be a ring along the boundary line of the working area, and sets the running path of the lawn mower in the second area to be a staggered straight line or a broken line; A control unit drives the lawn mower to traverse the first area according to the operation path determined by the path planning module, and then drives the lawn mower to traverse the second area inward; during this period, if the positioning signal of the lawn mower is lost, the navigation system is switched to run for a safe period, and if the positioning signal is restored within the safe period, the original navigation system is switched back to continue running; if the positioning signal is not restored within the safe period, the positioning abnormal point at this time is recorded, and the lawn mower is switched to traverse the second area.

9. The borderless lawn mower according to claim 9, characterized in that The first navigation system is a GPS positioning system; the second navigation system is an IMU inertial navigation system.

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