Self-propelled device system and boundary wire break detection method thereof

A self-propelled device system includes a self-propelled device, a boundary wire configured to define a work area of the self-propelled device and a signal transmitting unit electrically connected with the boundary wire configured to generate and send a boundary signal to the boundary wire that generates a magnetic field when flowing through the boundary wire. The self-propelled device has a signal receiving module and a control module. The signal receiving module uses the magnetic field caused by the boundary signal to generate a boundary wire inductive signal and the control module determines that the boundary wire has a wire break when a relevant parameter of the boundary wire inductive signal is less than or equal to a predefined threshold.

RELATED APPLICATION INFORMATION

This application claims the benefit of CN 201911371219.1, filed on Dec. 26, 2019, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

This disclosure relates to a garden tool, in particular to a self-propelled device system and a boundary wire break detection method thereof.

Generally, self-propelled devices such as lawn mowers and other outdoor gardening cutting tools are provided with operating handles for pushing; the operating handles are provided with switch boxes and control mechanisms near the grip portion to facilitate operators' operation and control. A lawn mower relies on the thrust applied by the operator to the operating handle to travel on the ground and perform cutting operations, which is very labor-intensive. With the continuous development of artificial intelligence, self-propelled devices that can walk, i.e., move, on their own have also been developed. Since the self-propelled device can walk automatically and perform certain predetermined tasks without human operation and intervention, it greatly saves manpower and material resources and brings convenience to the operator.

The emergence of self-propelled device has brought great convenience to users, allowing users to free themselves from the heavy gardening work. However, the self-propelled device generally moves within a boundary wire, and the boundary wire is connected with the signal transmitting unit. The signal transmitting unit generates a boundary signal and sends it to the boundary wire. The self-propelled device recognizes the boundary signal to control the self-propelled device to move within the boundary wire. However, when the boundary wire has a wire break problem, it is difficult to quickly locate the wire break position, thereby affecting the operation of the self-propelled device.

SUMMARY

A self-propelled device system, including: a boundary wire configured to define a work area of the self-propelled device; a signal transmitting unit electrically connected with the boundary wire, and configured to generate and send a boundary signal to the boundary wire, the boundary signal being enabled to generate a magnetic field when flowing through the boundary wire; and a self-propelled device, including: a signal receiving module for inducing a magnetic field change caused by the boundary signal to generate a boundary wire inductive signal; and a control module for receiving the boundary wire inductive signal and determining whether the boundary wire has a wire break. If a relevant parameter of the boundary wire inductive signal is less than or equal to a predefined threshold, determine that the boundary wire has a wire break.

Optionally, the boundary signal is an alternating current signal.

Optionally, the self-propelled device includes work modes of a fully automatic mowing mode and a wire break detection mode.

Optionally, the control module is further configured to:perform a multiply-add operation on the boundary wire inductive signal with the sine function or cosine function to obtain an amplitude of the boundary wire inductive signal;if the amplitude of the boundary wire inductive signal is less than or equal to a first predefined threshold, determine that the boundary wire has a wire break.

Optionally, in the wire break detection mode, the operation of the self-propelled device includes two steps of returning to the signal transmitting unit and walking along the boundary wire.

Optionally, the control module is configured to: in the wire break detection mode, control the self-propelled device to return to the signal transmitting unit; control the self-propelled device to walk along the boundary wire according to the boundary wire inductive signal; determine that a position of the boundary wire where the self-propelled device is located is a wire break position if an amplitude of the boundary wire inductive signal is less than or equal to a second predefined threshold.

Optionally, the self-propelled device further includes:an interactive interface communicatively connected with the control module; the interactive interface is configured to display the operating status information of the self-propelled device, and the user can control the start and work mode of the self-propelled device through the interactive interface.

Optionally, the control module is configured to:if an amplitude of the boundary wire inductive signal is less than or equal to a first predefined threshold, send a wire break prompt signal to the interactive interface to remind the user that the boundary wire has a wire break.

Optionally, the control module is configured to:if an amplitude of the boundary wire inductive signal is less than or equal to a second predefined threshold, send a position prompt signal to the interactive interface to prompt the user of the wire break position of the boundary wire.

Optionally, the interactive interface can be provided on a mobile terminal.

Optionally, the self-propelled device further includes:a mobile station to capture the GNSS or GPS position of the self-propelled device;the control module is configured to:obtain the GNSS or GPS position of the self-propelled device and output a corresponding control instruction to a walking assembly of the lawn mower to control the self-propelled device to move to the position of the signal transmitting unit.

A wire break detection method for a boundary wire of a self-propelled device system, the self-propelled device system includes: a boundary wire configured to define a work area of the self-propelled device; a signal transmitting unit, electrically connected with the boundary wire, for generating and sending a boundary signal to the boundary wire, and the boundary signal can generate a magnetic field when flowing through the boundary wire; and a self-propelled device; the wire break detection method includes the following steps: inducing the magnetic field generated when the boundary signal flows through the boundary wire; calculating an amplitude of the boundary wire induction signal; and determining that the boundary wire has a wire break if the amplitude of the boundary wire inductive signal is less than or equal to a first predefined threshold.

Optionally, the wire break detection method further includes: controlling the self-propelled device to walk along the boundary wire; inducing the magnetic field generated when the boundary signal flows through the boundary wire; calculating the amplitude of the boundary wire inductive signal; and determining that a position of the boundary wire where the self-propelled device is located is a wire break position if the amplitude of the boundary wire inductive signal is less than or equal to a second predefined threshold.

DETAILED DESCRIPTION

A self-propelled device system, taking an intelligent mowing system as an example, refer to the intelligent mowing system100shown inFIG.1, which includes a boundary module10and an intelligent lawn mower20. The boundary module10includes a boundary wire11and a signal transmitting unit12. The boundary wire11is used to define the work area of the intelligent lawn mower20, wherein the area located within the boundary wire11is the work area and the area located outside the boundary wire11is the non-working area, and the boundary wire11can be disposed on the ground. The signal transmitting unit12is electrically connected with the boundary wire11. The signal transmitting unit12generates a boundary signal BS and sends it to the boundary wire11. When the boundary signal BS flows through the boundary wire11, a magnetic field is generated. It can be understood that the boundary signal BS may be a current signal. In some examples, the signal transmitting unit12periodically provides an alternating current signal to the boundary wire11, and an alternating magnetic field is generated when the current signal flows through the boundary wire11. Specifically, the signal transmitting unit12may be a charging pile, which can periodically provide an alternating current signal to the boundary wire11, and also charge the intelligent lawn mower20. It can be understood that the self-propelled device system may also be an automatic snow blower system, etc., which is not limited here.

Referring toFIGS.2and3, the intelligent lawn mower20at least includes a body21, a cutting assembly22and a walking assembly23.

The cutting assembly22is generally installed under the body21for cutting grass or vegetation. Specifically, it may include a cutting element (not shown) for realizing the cutting function, a cutting motor221for driving the cutting element to rotate at a high speed, and a cutting drive controller222for controlling the cutting motor. The cutting assembly22may include more than one cutting elements, and correspondingly, the number of the cutting motors221may correspond to the number of cutting elements.

The walking assembly23, supported by the body21and rotatable, is configured to enable the intelligent lawn mower20to walk on the lawn. The walking assembly23includes a walking wheel. In some examples, the walking wheel includes a first walking wheel231and a second walking wheel232, and the cutting element is located between the first walking wheel231and the second walking wheel232. The number of the first walking wheels231is two, and the number of the second walking wheels232is also two. The second walking wheels232include a left walking wheel2321and a right walking wheel2322. The walking assembly23also includes a walking motor233, which is configured to drive the second walking wheel232. The number of walking motors is also two, which are respectively the left walking motor2331driving the left walking wheel2321and the right walking motor2332driving the right walking wheel2322. The walking assembly23further includes a walking drive controller235for controlling the walking motor233. The walking drive controller235includes: a first walking drive controller2351and a second walking drive controller2352. Specifically, the first walking drive controller2351is used to drive the corresponding left walking motor2331; the second walking drive controller235is used to control the corresponding right walking motor2332. In this way, when the two walking motors drive the respective second walking wheels232to rotate at different speeds, a speed difference occurs between the left walking wheel2321and the right walking wheel2322, so that the intelligent lawn mower20can make a turn.

The intelligent lawn mower20also includes a power supply module25, which supplies power to the intelligent lawn mower20. Optionally, the power supply module25is implemented as at least one battery pack, which is connected to the intelligent lawn mower20through the battery pack interface of the intelligent lawn mower20to provide electric power to the cutting motor221and the walking motor233. The power supply circuit is electrically connected with the power supply module25and the motor, so that the electrical energy output from the power supply device is provided to the motor to drive the cutting assembly22and the walking assembly23. It is worth mentioning that the intelligent lawn mower20can choose a fully automatic mowing mode or a manual mowing mode, that is, the user manually controls the intelligent lawn mower20to perform operations.

The intelligent lawn mower20is also provided with an interactive interface28for interacting with the user. The interactive interface28can display the operating status information of the intelligent lawn mower20, and is provided with buttons or switches for the user to control the start and operation of the intelligent lawn mower. In some examples, the interactive interface28is connected to the control module27. When the user transmits control commands through buttons or switches, the control module27obtains, analyzes and outputs corresponding control commands to corresponding controllers to control the operation of the intelligent lawn mower20. The interactive interface28and the control module27are communicably connected, and such a connection can be implemented in any suitable manner, including but not limited to wired or wireless connection. The interactive interface28can also be configured on a mobile terminal such as a mobile phone, so that a user can monitor and control the intelligent lawn mower20through a mobile terminal such as a mobile phone, which is very convenient.

Referring toFIG.4, the intelligent lawn mower20further includes a signal receiving module26and a control module27. The signal receiving module26is configured to induce the magnetic field changes generated by said boundary signal and generate a boundary wire inductive signal MS. The signal receiving module26can convert the magnetic field into a corresponding electrical signal. In some examples, the signal receiving module26includes an inductor, which induces a magnetic field and generates a corresponding electromotive force, thereby converting the magnetic field into a boundary wire inductive signal MS and passing it to the control module27. In other examples, the signal receiving module26includes a magnetic field detection sensor, which can detect an alternating magnetic field and convert it into an electrical signal output.

The control module27is configured to receive the boundary wire inductive signal MS, and control the intelligent lawn mower20to walk based on a relevant parameter of the boundary wire inductive signal MS. In some examples, the intelligent lawn mower is controlled to enter the wire break detection mode when the relevant parameter of the boundary wire inductive signal is less than or equal to a predefined threshold.

The control module27is configured to determine whether the intelligent lawn mower20is in the work area within the boundary wire11based on the phase or change of the boundary wire inductive signal; the control module27is also configured to determine The distance between the intelligent lawn mower20and the boundary wire11based on the amplitude of the boundary wire inductive signal MS. The intelligent lawn mower20further selects a work mode based on the amplitude of the boundary wire inductive signal MS so as to send control signals to the walking drive controller to control the movement of the intelligent lawn mower20, wherein the movement modes include: fully automatic mowing mode and wire break detection mode.

The control module27further includes a signal processor273and a microcontroller274. The signal processor273is connected with the signal receiving module26for receiving the boundary wire inductive signal MS, processing the boundary wire inductive signal MS and transmitting the processed signal PS to the microcontroller274. The microcontroller274receives the boundary wire inductive signal MS to calculate the amplitude and phase of the boundary wire inductive signal MS, so as to determine the distance between the intelligent lawn mower20and the boundary wire11, and whether the intelligent lawn mower20is in the work area inside the boundary wire11or the non-working area outside the boundary wire11. In some examples, after the microcontroller274receives the boundary wire inductive signal MS, it may perform multiply-add operations on the waveform function of the boundary wire inductive signal MS with the sine function or the cosine function to calculate the amplitude and the phase of the boundary wire inductive signal MS to determine the distance between the intelligent lawn mower20and the boundary wire11, and whether the intelligent lawn mower20is in the work area inside the boundary wire11or the non-working area outside the boundary wire11, and control the walking direction of the intelligent lawn mower20according to the results. The microcontroller274is also configured to compare the amplitude of the boundary wire inductive signal MS with a predefined threshold stored in advance to select the work mode of the intelligent lawn mower.

Specifically, referring toFIG.5, the microcontroller274further includes a calculation unit2741, a comparison unit2742, and a control unit2743.

The calculation unit2741is connected with the signal processor273, and calculates the amplitude and phase of the boundary wire inductive signal MS according to the processed signal PS, and transmits the calculated signal to the comparison unit2742, and compares the amplitude of the boundary wire inductive signal MS with a first predefined threshold stored in advance. If the amplitude of the boundary wire inductive signal MS is greater than the first predefined threshold, the comparison unit2742sends a first control signal to the control unit2743to control the intelligent lawn mower20to work in the fully automatic mowing mode, which automatically performs mowing within the boundary wire11.

If the comparison unit2742finds that the amplitude of the boundary wire inductive signal MS is less than or equal to the first predefined threshold, it determines that the boundary wire11has a wire break, i.e., there is a wire break position on the boundary wire11, and the comparison unit2742sends a second control signal to the control unit to control the intelligent lawn mower20to enter the wire break detection mode. In the wire break detection mode, the operation of the intelligent lawn mower20has two steps: returning to the signal transmitting unit12and walking along the boundary wire11. After the intelligent lawn mower20enters the wire break detection mode, the control module27sends a control signal to the walking assembly to control the intelligent lawn mower20to first return to the signal transmitting unit12, then walk along the boundary wire11, and then search for the wire break position on the boundary wire11according to the amplitude of the boundary wire inductive signal MS.

Specifically, the control module27detects that the amplitude of the boundary wire inductive signal MS is less than or equal to the first predefined threshold and sends a wire break prompt signal to the interactive interface28to remind the user that the boundary wire11may have a wire break. The user switches the intelligent lawn mower20to the wire break detection mode through the interactive interface28, and the user can manually move the intelligent lawn mower to the signal transmitting unit12. In other examples, the user controls the intelligent lawn mower20through the interactive interface28to automatically return to the signal transmitting unit12. For example, the user make a select on the interactive interface28to make the intelligent lawn mower enter the wire break detection mode, and the interactive interface28transmits the return command to the control module27, and the control module27obtains, analyzes, and outputs corresponding control commands to the walking assembly23to control the intelligent lawn mower to return to the signal transmitting unit12.

As shown inFIG.6, in some examples, the intelligent lawn mower20is further provided with a mobile station30, and the mobile station30moves with the intelligent lawn mower20to capture the GNSS or GPS position of the intelligent lawn mower20. The mobile station30includes a receiving antenna31to receive GNSS or GPS position signals from satellites, thereby determining the position of the intelligent lawn mower20. The user sends the return instruction to the control module27through a one-key return button. The control module27obtains the GNSS or GPS position signals received by the mobile station30, and outputs the corresponding control instruction to the walking assembly23to control the movement of the intelligent lawn mower20to the predefined coordinate position of the signal transmitting unit12. It is understood that the GNSS or GPS position is represented by the coordination of the longitude position and the latitude position. For example, the obtained GNSS or GPS position may be 31°51′ longitude and 118°48′ latitude, then the GNSS or GPS position is represented as (N 31°51′, E 118°48′). The mobile station30may be detachably mounted to the intelligent lawn mower20.

After the intelligent lawn mower20returns to the position of the transmitting unit12, it walks along the boundary wire11, and searches for the wire break position according to the amplitude of the boundary wire inductive signal MS.

Referring toFIG.7, in an example, the signal transmitting unit12periodically provides an alternating current signal to the boundary wire11. Although a closed loop cannot be formed due to the existence of a wire break position on the boundary wire11, still there is a changing voltage signal on the boundary wire11, and the changing voltage signal generates a magnetic field. When the intelligent lawn mower20approaches the boundary wire11, the signal receiving module26induces the change in the magnetic field and generates the boundary wire inductive signal WS. It can be understood that the signal strength of the boundary wire inductive signal WS when the boundary wire is broken is less than the signal strength of the boundary wire inductive signal MS when the boundary wire is normal. Therefore, when the boundary wire is broken, the control module27detects that the amplitude of the boundary wire inductive signal WS is lower than the amplitude of the boundary wire inductive signal MS. In this example, the boundary signal BS is a sine wave signal. It can be understood that the boundary signal BS is not limited to a sine wave signal.

When the intelligent lawn mower20is walking along the boundary wire11, and the control module27detects that the amplitude of the boundary wire inductive signal WS is less than a second predefined threshold, it is determined that the location of the intelligent lawn mower20is the wire break position of the boundary wire. Specifically, the signal receiving module26induces the magnetic field and generates the boundary wire inductive signal WS. The signal processor273receives the boundary wire inductive signal WS, processes and transmits the processed signal PS′ to the microcontroller274. The calculation unit2741in the microcontroller274calculates the amplitude and phase of the boundary wire inductive signal WS based on the processed signal PS′ and transmits them to the comparison unit2742. The comparison unit2742compares the amplitude of the boundary wire inductive signal WS with the second predefined threshold stored in advance: when the amplitude of the boundary wire inductive signal WS is less than or equal to the second predefined threshold, it is determined that the intelligent lawn mower20is at a wire break position on the boundary wire11, and the comparison unit2742sends a stop control signal to the control unit to control the intelligent lawn mower20to stop moving. In some examples, the control module27further sends a position prompt signal to the interactive interface28to display the wire break position to the user. It is understandable that when the control module27detects the wire break position on the boundary wire11, it sends a position prompt signal to make the intelligent lawn mower send position prompt information or perform physical actions that can be sensed by the user, for example, after the intelligent lawn mower20detects the wire break position, the intelligent lawn mower20may stop moving and continuously flash the indicator light provided on the intelligent lawn mower to prompt the user of the position of the intelligent lawn mower20.

The signal processor273further includes: a filtering unit2731and an amplifying unit2732.

The filtering unit2731is connected with the signal receiving module26and is configured to filter the boundary wire inductive signal; the amplifying unit2732is configured to amplify the filtered signal to obtain the final processed signal PS'. The amplifying unit2732and the calculation unit2741are connected.

In this way, the intelligent lawn mower can quickly determine whether the boundary wire has a wire break according to the amplitude of the boundary wire inductive signal MS, and can accurately and quickly detect the wire break position automatically, which effectively improves the detection efficiency and saves manpower.

Referring toFIG.8, a schematic flowchart of the method for the intelligent lawn mower20to determine whether the boundary wire11has a wire break includes the following steps:

In step S101, induce the magnetic field generated when the boundary signal flows through the boundary. The signal transmitting unit12generates a boundary signal BS and sends it to the boundary wire11. When the boundary signal BS flows through the boundary wire11, a magnetic field is generated. The signal receiving module26can induce the change of the magnetic field caused by the boundary wire and generate a boundary wire inductive signal MS.

In step S102, calculate the amplitude of the boundary wire inductive signal MS. The control module27is configured to receive the boundary wire inductive signal MS. The signal processor273in the control module27is configured to receive the boundary wire inductive signal MS and generate a processed signal PS. The microcontroller274in the control module27is configured to receive the processed signal PS, and the calculation unit2741in the microcontroller274is configured to calculate the amplitude of the boundary wire inductive signal MS according to the processed signal PS.

In step S103, determine whether the amplitude of the boundary wire inductive signal MS is less than or equal to a first predefined threshold. The comparison unit2742compares the amplitude of the boundary wire inductive signal MS with the first predefined threshold stored in advance, and if the amplitude is less than or equal to the first predefined threshold, execute S104; if not, execute S105.

In step S104, control the intelligent lawn mower20to enter the wire break detection mode. The comparison unit2742sends a second control signal to the control unit to send a wire break prompt signal to the interactive interface28to prompt the user that the boundary wire11may have a wire break, and the user switches the intelligent lawn mower20to the wire break detection mode through the interactive interface28.

In step S105, control the intelligent lawn mower to enter the fully automatic mowing mode. The comparison unit2742sends a first control signal to the control unit2743to control the intelligent lawn mower20to work in the fully automatic mowing mode, which automatically performs mowing within the boundary wire11to trim the lawn.

Referring toFIG.9, a schematic flowchart of the method for the intelligent lawn mower20to search for the wire break position in the wire break detection mode includes the following steps:

In step S201, the intelligent lawn mower20returns to the signal transmitting unit12, and starts to walk along the boundary wire11from the signal transmitting unit12. In some examples, the user manually moves the intelligent lawn mower to the signal transmitting unit12; in other examples, the intelligent lawn mower20automatically returns to the signal transmitting unit12in the wire break detection mode.

In step S202, induce the magnetic field generated when the boundary signal flows through the boundary. The signal transmitting unit12generates a boundary signal BS and sends it to the boundary wire11. When the boundary signal BS flows through the boundary wire11, a magnetic field is generated. The intelligent lawn mower20walks along the boundary wire11, and the signal receiving module26induces a magnetic field change caused by the boundary wire11, and generates the boundary wire inductive signal WS.

In step S203, calculate the amplitude of the boundary wire inductive signal WS. The control module27is configured to receive the boundary wire inductive signal WS. The signal processor273in the control module27is configured to receive the boundary wire inductive signal WS and generate a processed signal PS′. The microcontroller274in the control module27is configured to receive the processed signal PS′, and the calculation unit2741in the microcontroller274is configured to calculate the amplitude of the boundary wire inductive signal WS according to the processed signal PS′.

In step S204, determine whether the amplitude of the boundary wire inductive signal WS is less than the second predefined threshold. The comparison unit2742compares the amplitude of the boundary wire inductive signal WS with the second predefined threshold stored in advance, and if the amplitude is less than or equal to the second predefined threshold, execute S205; if not, execute S201.

In step S205, determine that the intelligent lawn mower20is at the wire break position of the boundary wire11, and control the intelligent lawn mower to stop moving. The comparison unit2742sends a stop control signal to the control unit to control the intelligent lawn mower20to stop moving. In some examples, the control module27further sends a position prompt signal to the interactive interface28to display the wire break position to the user.

The above shows and describes the basic principles, main features and advantages of the invention hereinafter claimed. Those skilled in the art should understand that the above-mentioned examples do not limit the claimed invention in any form, and all technical solutions obtained by equivalent substitutions or equivalent transformations fall within the protection scope of the claimed invention.