Lawn mowing equipment

Abstract

To provide a technology that extends the life of on-vehicle batteries in an autonomous lawn mower.SOLUTION: As shown in Figure 8(b), batteries are charged with a charging current set to A0 when the grass is dense. When the grass is sparse, batteries are charged with a current smaller than A0 (A1, A2, or A3). As shown in Figure 8(a), the smaller the charging current is, the longer the service life of the on-vehicle battery becomes.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a grass cutting facility comprising an autonomous control type lawn mower and a stationary power supply unit.

Background Art

[0002] Conventionally, grass cutting operations including lawn mowing have been carried out by manned lawn mowers. Due to the soaring labor costs, unmanned lawn mowers have been demanded. As one type of unmanned lawn mower, there is an autonomous control type lawn mower that mows grass while autonomously traveling, and various types of this type of lawn mower have been proposed (see, for example, Patent Document 1 (FIGS. 1 and 3)).

[0003] The autonomous control type lawn mower shown in Patent Document 1 is equipped with an in-vehicle battery, and travels and rotates a cutter by electric energy supplied from this in-vehicle battery. When the output voltage of the in-vehicle battery reaches the lower limit voltage, it returns to the charging station. It is charged at the charging station. After charging, it returns to the work site. Since the above steps are performed unmanned and automatically, labor costs can be saved.

[0004] As the in-vehicle battery, lead-acid batteries have been used in the past, but in recent years, lightweight and high-performance lithium-ion batteries have been used. Both lead-acid batteries and lithium-ion batteries deteriorate when charged and discharged repeatedly, and when the deterioration progresses, they are discarded or recycled.

[0005] The shorter the lifespan, the more scarce metals such as lithium are discarded in a short period of time, leading to wasteful use of the earth's resources. Even when recycling, the shorter the lifespan, the higher the recycling frequency, and as a result, the recycling cost increases. Therefore, as there is a demand for effective utilization of the earth's resources and compression of recycling costs, there is also a demand for extending the lifespan of the in-vehicle battery in the autonomous control type lawn mower.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a technique for extending the service life of an in-vehicle battery in an autonomous control type lawn mower.

Means for Solving the Problems

[0008] [Explanation of Terms] The special terms used in this specification are as follows. Return means that the autonomous control type lawn mower returns to the stationary power supply unit. The return time refers to the time when the autonomous control type lawn mower reaches the stationary power supply unit. Departure means that the autonomous control type lawn mower departs from the stationary power supply unit. The departure time refers to the time when the autonomous control type lawn mower departs from the stationary power supply unit.

[0009] Stationary means being installed on the ground or the like. In-vehicle means being mounted on the autonomous control type lawn mower.

[0010] Battery refers to a secondary battery capable of charge and discharge, such as a lead-acid battery or a lithium-ion battery. The lower limit voltage refers to the voltage obtained by adding the voltage used for return to the minimum voltage in the usage range of the battery. Charger refers to a device that charges the battery. Charging current refers to the value of the current used for charging. Rated charging current refers to the charging current recommended by the battery supplier.

[0011] One working time refers to the time from the departure time to the return time. The scheduled mowing time refers to the time obtained by recording one working time in the past one month, six months, or twelve months and calculating the arithmetic mean. The number of times refers to one round from starting to returning, and it means the cumulative number of times counted for each return. The predetermined number of times refers to the number of times required or scheduled between the work start time and the work end time.

[0012] [Claim 1] The invention according to claim 1 includes an in-vehicle battery and an in-vehicle control unit, and is a self-propelled mower that performs mowing while self-propelling with the in-vehicle battery, a mowing facility comprising a stationary control unit and a stationary power supply unit for charging the in-vehicle battery, the in-vehicle control unit performs control to return the self-propelled mower to the stationary power supply unit when the voltage of the in-vehicle battery drops to a predetermined lower limit voltage, and to start the self-propelled mower from the stationary power supply unit when charging is completed, the stationary power supply unit is provided with a charger capable of selecting a rated charging current recommended for the in-vehicle battery and a charging current smaller than this rated charging current, the stationary control unit calculates a one-work-hour from the start time and return time of the self-propelled mower, and selects the rated charging current when this one-work-hour is less than or equal to a pre-stored work scheduled time, when the one-work-hour exceeds the work scheduled time, it is characterized in that charging is performed by selecting the smaller charging current and a smaller charging current corresponding to the excess time.

[0013] [Claim 2] The invention according to claim 2 is the mowing facility according to claim 1, the stationary control unit further counts the number of starts in a day, and when this number reaches a pre-stored predetermined number of times, it performs control to end the work for that day.

[0014] [Claim 3] The invention according to claim 3 is the mowing facility according to claim 2, the stationary control unit further monitors the length of the one-work-hour, and when it is long, it reduces the predetermined number of times for the next day, and when it is short, it increases the predetermined number of times for the next day. [Advantages of the Invention]

[0015] [Effect of Claim 1] In the invention according to Claim 1, when the working time of one operation exceeds the planned working time, charging is performed with a small charging current. When the grass is dense or the height of the grass is long, the in-vehicle battery is severely consumed, so the working time of one operation is shortened. Conversely, when the grass is sparse or the height of the grass is short, the consumption of the in-vehicle battery becomes gentle and the working time of one operation becomes long.

[0016] For example, when charging is performed with a current of 50% of the rated charging current, the charging time becomes twice as long. When the charging time becomes twice as long, the number of starts is halved. However, when the working time of one operation exceeds the planned working time, since the grass is sparse or the height of the grass is short, even if the number of starts decreases, it does not matter. As a result, charging with a small charging current is allowed.

[0017] The smaller the charging current, the more the deterioration of the battery is suppressed and the longer the life of the battery becomes. Therefore, according to the present invention, a technique is provided that can extend the life of the in-vehicle battery in a self-controlled lawn mower.

[0018] [Effect of Claim 2] In the invention according to Claim 2, the stationary control unit further counts the number of starts in one day, and when this number reaches a predetermined number stored in advance, controls to end the work for that day are executed.

[0019] This type of self-controlled lawn mower can operate unmanned for 24 hours, but considering failure response and other abnormal responses, it is desirable to operate within the time when the administrator is present (for example, from 8:00 to 17:00). In this case, 8:00 can be set as the work start time and 17:00 can be set as the work end time.

[0020] Assuming that the growth rate of the grass is constant, the grass grows during the rest time (17:00 to 8:00). In summer, mowing starts at 8:00 and ends around 16:00, but in spring and autumn, it is assumed that mowing starts at 8:00 and ends around 13:00. According to claim 1, there is a possibility of causing wasteful work from around 13:00 to 17:00 in spring or autumn. According to claim 2, since the number of times is limited and the work is terminated when the number of times is reached even within the time, no wasteful work is caused. As a result, the in-vehicle battery can be put on standby, and the life can be further extended.

[0021] [Effect of Claim 3] In the invention according to claim 3, further control is executed to monitor the length of one working time, reduce the predetermined number of times on the next day when it is long, and increase the predetermined number of times on the next day when it is short. In claim 2, the predetermined number of times is artificially determined, but the setting change work is troublesome. As a countermeasure, in claim 3, the fixed control unit is entrusted with the modification. That is, when the one working time is long, since the grass is sparse or the height of the grass is short, the number of starts can be reduced without any problem. From this finding, when the one working time is long, the predetermined number of times on the next day is reduced. According to claim 3, since the predetermined number of times is automatically corrected, the burden on the administrator is reduced.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0023] Embodiments of the present invention will be described below based on the accompanying drawings.

Examples

[0024] [Lawn mowing equipment] As shown in FIG. 1, the lawn mowing equipment 40 includes an autonomous control type lawn mower 10 that mows grass while autonomously traveling, and a stationary power supply unit 50 that charges the in-vehicle battery (reference numeral 25 in FIG. 5) mounted on the autonomous control type lawn mower 10.

[0025] The autonomous control type lawn mower 10 is a moving body, and the stationary power supply unit 50 is a non-moving body installed on the ground or a fixed object. The control unit is mounted or installed on both the moving body and the non-moving body. For convenience, what is mounted on the moving body is referred to as an in-vehicle control unit, and what is installed on the non-moving body is referred to as a stationary control unit.

[0026] In addition, the traveling range of the autonomous control type lawn mower 10 is defined by an area wire 42 laid in a circular shape in the mowing field 41. By energizing the area wire 42, the autonomous control type lawn mower 10 electrically detects the area wire 42, and its traveling is controlled so as not to go outside the area wire 42.

[0027] [Stationary power supply unit] The stationary power supply unit 50 includes a charging station 51 where the autonomous control type lawn mower 10 docks, a charger 52 built in or attached to the charging station 51, a stationary control unit 53 that performs comprehensive control including the charger 52, and a transmission unit 54 that transmits and receives signals between the in-vehicle control unit (reference numeral 27 in FIG. 5).

[0028] The details of the charger 52 will be described with reference to FIG. 6. First, based on FIGS. 2 to 5, a structural example of the autonomous control type lawn mower 10 will be described.

[0029] [Autonomous control type lawn mower] As shown in FIG. 2, the autonomous control type lawn mower (hereinafter referred to as the lawn mower) 10 includes a front wheel 11, a left rear wheel 12L, and a right rear wheel 12R. The lawn mower 10 has a horizontally long rectangular opening 14 at the center of the front surface of the cover 13. A lawn mower side coupling member (reference numeral 36 in FIG. 5) is disposed at the back of the opening 14.

[0030] As shown in FIG. 3, a cutter housing 16 is provided between the front wheel 11 and the rear wheel axle 15.

[0031] As shown in FIG. 4, in the lawn mower 10 that includes a rotating cutting blade 19, a front wheel 11 disposed in front of the cutting blade 19, and rear wheels 12L and 12R disposed behind the cutting blade 19 when viewed from the bottom, the lawn mower 10 includes a left wire sensor 21L and a right wire sensor 21R disposed on the front wheel 11 side with respect to the cutting blade 19.

[0032] The left wire sensor 21L and the right wire sensor 21R can be disposed at any position as long as they are outside the turning circle 22 of the cutting blade 19. The left wire sensor 21L is disposed at a position α ahead of the turning circle 22 and β to the left (right in the figure) of the turning circle 22. Similarly, the right wire sensor 21R is disposed at a position α ahead of the turning circle 22 and β to the right of the turning circle 22. β may be the same as or different from α.

[0033] FIG. 5 is a plan view obtained by inverting FIG. 4. As shown in FIG. 5, the vehicle-mounted control unit 27 includes a receiving unit 35 that receives a wireless signal emitted by the transmitting unit (reference numeral 54 in FIG. 1). Further, the remaining voltage of the vehicle-mounted battery 25 is detected by the vehicle-mounted voltmeter 38, and this detection information is sent from the vehicle-mounted control unit 27 to the stationary control unit 53.

[0034] The cutting blade 19 is driven by a cutting blade motor 24. This cutting blade motor 24 is powered by the vehicle-mounted battery 25 and its rotational speed, forward rotation, stop, and reverse rotation are controlled by the vehicle-mounted control unit 27 via a driver 26. When the cutting blade motor 24 is in an overload state, reverse rotation control is performed.

[0035] The front wheels 11 are driven by a front wheel motor 28. This front wheel motor 28 is powered by the vehicle-mounted battery 25 and its rotational speed, forward rotation, stop, and reverse rotation are controlled by the vehicle-mounted control unit 27 via a driver 29. The front wheels 11 are steering wheels and are steered by a steering motor 31. This steering motor 31 is powered by the vehicle-mounted battery 25 and straight-ahead, left steering, and right steering are controlled by the vehicle-mounted control unit 27 via a driver 32.

[0036] The left rear wheel 12L is driven by a left rear wheel motor 33L. This left rear wheel motor 33L is powered by the vehicle-mounted battery 25 and its rotational speed, forward rotation, stop, and reverse rotation are controlled by the vehicle-mounted control unit 27 via a driver 34L. Similarly, the right rear wheel 12R is driven by a right rear wheel motor 33R. This right rear wheel motor 33R is powered by the vehicle-mounted battery 25 and its rotational speed, forward rotation, stop, and reverse rotation are controlled by the vehicle-mounted control unit 27 via a driver 34R.

[0037] By the way, many conventional lawn mowers are not all-wheel drive vehicles. Therefore, for some reason (for example, the cutter housing surrounding the cutting blade rides up on a bump), if the rear wheels, which are the drive wheels, lift off the ground, the vehicle cannot move. In this case, the administrator has to walk up to the lawn mower 10 and disengage it from the bump. This increases the burden on the administrator.

[0038] On the other hand, since the lawn mower 10 of the present invention shown in FIG. 5 is an all-wheel drive vehicle, if the front wheels 11 are in contact with the ground, even if the rear wheels 12L and 12R are lifted, it can disengage by itself and continue to run. As a result, the burden on the administrator is significantly reduced.

[0039] In addition, in the lawn mower 10 of the present invention, the front wheels 11 may be two left and right wheels, but in the embodiment, they are a single wheel. If there is a single wheel, the number of the front wheel motor 28, the driver 29, the steering motor 31, and the driver 32 is halved, and cost reduction can be achieved.

[0040] For drawing convenience, the in-vehicle battery 25 and the in-vehicle control unit 27 shown outside the cover 13 are arranged inside the cover 13. At the front part of the cover 13, for example, a V-shaped lawn mower side coupling member 36 is housed, and a charging terminal 37 is provided on the lawn mower side coupling member 36. Charging is performed from the outside to the in-vehicle battery 25 via the charging terminal 37.

[0041] In addition, the in-vehicle control unit 27 receives signals detecting the area wire (reference numeral 42 in FIG. 1) from the left wire sensor 21L and the right wire sensor 21R.

[0042] [Charger] As shown in FIG. 6, the charger 52 includes, for example, a power source 57 and a resistor 58 provided in a circuit 56, sub-circuits 61 to 63 branched from the middle of the resistor 58, first to third switch means 65 to 67 respectively provided in these sub-circuits 61 to 63, a fourth switch means 68 provided in the circuit 56, and a sub-control unit 69 that selectively turns one of the first to fourth switch means 65 to 68 "on" and turns the rest "off".

[0043] According to Ohm's law, (voltage ÷ resistance) = current. The output voltage of the power source 57 is constant. Therefore, when the resistance changes, the current changes. When only the first switch means 65 is turned "on", a current of A0 flows through the circuit 56. When only the second switch means 66 is turned "on", a current of A1 flows through the circuit 56. Due to the difference in the length of the resistor 58, A1 is smaller than A0.

[0044] When only the third switch means 67 is turned "on", a current of A2 flows through the circuit 56. Due to the difference in the length of the resistor 58, A2 is smaller than A1. When only the fourth switch means 68 is turned "ON", the current of A3 flows through the circuit 56. Due to the difference in the length of the resistor 58, A3 becomes smaller than A2.

[0045] By the way, for a rechargeable secondary battery, a rated charging current recommended by a battery supplier (such as a battery manufacturer) is determined. Therefore, A0 is defined as the rated charging current. And since A3 < A2 < A1 < A0, A1 to A3 are charging currents smaller than the rated charging current A0.

[0046] In this example, the small charging currents are three types of A1 to A3, but the number of types can be arbitrarily changed. Also, the charger 52 only needs to exhibit the same operation as in FIG. 6, and the structure and configuration can be arbitrarily changed.

[0047] [Control Flow] The control flows of the stationary control unit (FIG. 1, reference numeral 53) and the in-vehicle control unit (FIG. 5, reference numeral 27) implemented using the charger 52 described above will be described below. As shown in step number (hereinafter abbreviated as ST) 01 of FIG. 7, when the planned mowing time Tave corresponding to an average one working time and the lower limit voltage for the in-vehicle battery are not stored in the stationary control unit, they are stored in this step. When they are stored, the storage is maintained.

[0048] In ST02, when the work start time is not set or needs to be corrected, it is set. When it is set and there is no need to correct it, the setting is maintained. In ST03, when the work end time is not set or needs to be corrected, it is set. When it is set and there is no need to correct it, the setting is maintained.

[0049] In ST04, the mower is made to standby at the charging station. Charging is completed during standby. At ST05, check whether the work start time has been reached. If not, continue waiting. When the work start time is reached, start moving and record the start time Ts (ST06). After that, perform the mowing operation. During the operation, continuously measure the battery voltage Vact with an in-vehicle voltmeter (Fig. 5, reference numeral 38), and send the information to the stationary control unit (ST07).

[0050] At ST08, check whether the battery voltage Vact has reached the lower limit voltage. If not, continue the mowing operation. When the lower limit voltage is reached, return at ST09. At ST10, record the return time Tg.

[0051] At ST11, calculate the one-work-hour Tw1. The calculation formula is Tw1 = (start time Ts - return time Tg). The reason for providing this step is as follows. When the grass is dense or the grass height is long, the consumption of the in-vehicle battery becomes severe. The more severe the consumption, the shorter the one-work-hour calculated by (start time Ts - return time Tg). Conversely, when the grass is sparse or the grass height is short, the consumption of the in-vehicle battery becomes gentle and the one-work-hour becomes long.

[0052] That is, by calculating the one-work-hour Tw1, it is possible to indirectly know the severity of the load (burden) on the in-vehicle battery. Based on this finding, the inventors execute the following steps.

[0053] At ST12, check whether the one-work-hour Tw1 is less than or equal to the pre-stored planned mowing time Tave. If not, proceed to ST14. If it is less than or equal to the planned mowing time Tave, it is determined that the load on the in-vehicle battery is as expected (or above the assumption), and select the charging current A0 (ST13). A0 is the recommended charging current, and favorable charging of the in-vehicle battery is performed.

[0054] At ST14, check whether one working time Tw1 is less than or equal to the scheduled mowing time Tave plus, for example, 15 minutes. If not, proceed to ST16. If it is the time obtained by adding 15 minutes to the scheduled mowing time Tave, it is assumed that the grass is sparse or the grass height is short. Based on this assumption, no actual harm will occur even if the subsequent mowing work is reduced. As part of the reduction, it is conceivable to reduce the number of times. If it is okay to reduce the number of times, an increase in the charging time is allowed. Based on this finding, select A1 which is smaller than A0 as the charging current (ST15).

[0055] Furthermore, at ST16, check whether one working time Tw1 is less than or equal to the scheduled mowing time Tave plus, for example, 30 minutes. If not, proceed to ST18. If it is the time obtained by adding 30 minutes to the scheduled mowing time Tave, it is assumed that the grass is even sparser or the grass height is even shorter. Based on this assumption, no actual harm will occur even if the subsequent mowing work is further reduced. As part of the reduction, it is further conceivable to reduce the number of times. If it is okay to further reduce the number of times, an even further increase in the charging time is allowed. Based on this finding, select A2 which is smaller than A1 as the charging current (ST17).

[0056] At ST18, select A3 which is smaller than A2 as the charging current. Then, at ST19, perform charging. The charging current used for this charging can be arranged as shown in Table 1.

[0057]

Table 1

[0058] For the sake of convenience, the scheduled mowing time Tave is set to 60 minutes. If one working time Tw1 is 60 minutes or less, charging is performed at the rated charging current A0. If the working time Tw1 exceeds 60 minutes and is equal to or less than 75 minutes, charging is carried out at a charging current A1 that is smaller than the rated charging current A0. If the working time Tw1 exceeds 75 minutes and is equal to or less than 90 minutes, charging is carried out at a charging current A2 that is smaller than the charging current A1. If the working time Tw1 exceeds 90 minutes, charging is carried out at a charging current A3 that is smaller than the charging current A2.

[0059] The effects in ST11 to ST19 will be described based on FIGS. 8(a) and (b). In a rechargeable secondary battery, it is known that when the charging current is increased for the purpose of shortening the charging time, internal heat generation becomes significant and the battery life is shortened. Conversely, when the charging current is decreased, internal heat generation is alleviated and the battery life is prolonged. According to this rule of thumb, as shown in FIG. 8(a), if the left vertical axis represents the life of the in-vehicle battery, compared with the life at A0, the life at A1 is longer, the life at A2 is even longer, and the life at A3 is even longer.

[0060] If the right vertical axis represents the time required for charging, compared with the charging time at A0, the charging time at A1 is longer, the charging time at A2 is even longer, and the charging time at A3 is even longer.

[0061] FIG. 8(b) is a graph showing the number of operations performed from the start time of the operation to the end time of the operation. Mowing and charging are repeated from the start time of the operation to the end time of the operation. When the charging current is A0, mowing is performed a certain number of times. When the charging current is A1, since the charging time is extended, the number of mowing operations decreases. When the charging current is A2, since the charging time is further extended, the number of mowing operations further decreases.

[0062] When the charging current is A3, since the charging time is further extended, the number of mowing operations further decreases. However, as noted on the horizontal axis, even if the number further decreases, the grass is sparse, so no problems occur.

[0063] When fully charged at ST19 in FIG. 7, check whether the work end time has been reached at ST20. If not, return to ST06 and continue the work. When it is confirmed that the work end time has been reached at ST20, end the work for this time (today). By the above ST01 to ST20, the long life of the in-vehicle battery can be achieved.

[0064] Next, further extension of the service life is considered. Assume a model as shown in FIG. 9. That is, the grass grows and its height increases from the work end time (1) to the work start time (2). The height of the grass shortens from the work start time (2) to the end time of the mowing work (3). In summer, since the growth is fast, it changes as shown by the solid line. On the other hand, in spring and autumn, since the growth is slow, it becomes as shown by the broken line.

[0065] That is, in the broken line, the substantial mowing of the grass ends at point A. From point A to the work end time (3), although the mower performs autonomous driving, almost no mowing is done. However, starting and charging are repeated also from point A to the work end time (3). If the work is ended at point B after point A, there will be no wasteful use, and further extension of the service life of the in-vehicle battery is expected.

[0066] A modification example that can meet this expectation will be described based on FIG. 10. Note that in FIG. 10, based on FIG. 7, the steps marked with ※ have their contents changed from FIG. 7, and the steps marked with ※※ are newly added. To avoid duplicate explanations, the steps marked with ※ and ※※ will be mainly explained. For the steps without ※ or ※※, the description in FIG. 7 will be incorporated and the explanation will be omitted.

[0067] [Control flow related to the modification example] At ST02A, when the work start time, work end time, and the predetermined number Nset have not been set, or when they are to be corrected, set them. The predetermined number Nset is the number of starts determined by the administrator considering the grass situation. When it is set and does not need to be corrected, the setting is maintained. In ST03A, reset the number Nact of the previous time or the day before.

[0068] In ST09A, return and record the return time Tg. In ST10A, add 1 to the number Nact. By this step, the number of operations is accumulated.

[0069] Then, add ST21 after ST20. In ST21, check whether the number Nact has reached the predetermined number Nset. The predetermined number Nset corresponds to point B in Fig. 9. If the answer is no in ST21, the operation continues, but when the number Nact reaches the predetermined number Nset, the operation ends. By adding ST21 to the control, the in-vehicle battery can be made to have a longer life than in Fig. 7.

[0070] Incidentally, the setting of the predetermined number Nset in ST02A is generally manually performed by the manager of the mowing field. However, since this type of setting is troublesome, automatic setting is desired. A further modification example that can meet this requirement will be described based on Figs. 11 and 12.

[0071] [Control flow related to further modification example] In Figs. 11 and 12, based on Fig. 10, the steps marked with ※ have their contents changed from Fig. 10, and the steps marked with ※※ are newly added. For the steps without ※ or ※※, the descriptions in Figs. 7 and 10 are incorporated and the descriptions are omitted.

[0072] In ST01B of Fig. 11, add the storage of the average number Nave. The average number Nave is desirably the average number from the start time to the end time of the operation in three seasons except winter. The average number Nave may be an approximate value (however, a positive integer).

[0073] When changing the work start time and work end time in ST02B, change them. In ST02.1, check whether there is a predetermined number of times Nset (whether it is specified). Since it is not the first time, proceed to ST02.2 and temporarily set the predetermined number of times Nset as the average number of times Nave. From the second time onwards, since there is (it is specified), proceed from ST02.1 to ST03B.

[0074] In ST03B, reset the number of times Nact of the previous day or the previous time. At the same time, reset the number of times Na0 of A0 and the number of times Na3 of A3. Add ST15.5 after ST15, and integrate the number of times Na1 of A1 in this ST15.5. Similarly, add ST18.5 added after ST18, and integrate the number of times Na3 of A3 in this ST18.5.

[0075] In ST22 of FIG. 12, check whether the number of times Na3 of A3 is, for example, 80% or more of the average number of times Nave. The fact that the number of times Na3 of A3 is large means that referring to the horizontal axis of FIG. 8(b), the grass is sparse. In this case, reducing the number of operations will not cause any actual harm. Therefore, in ST23, reduce the predetermined number of times Nset by one. This information will be reflected after the next work start time. By this process, the life of the in-vehicle battery can be further extended.

[0076] However, if the predetermined number of times Nset is continuously reduced, it may become unsuitable for the practical use of the grass cutting field. That is, if the predetermined number of times Nset is too small, it cannot cope with the period when the grass grows quickly (such as in summer). In summer, the number of times Na3 of A3 decreases, and the number of times of A2, A1, and A0 increases. These will be monitored by the number of times of A1.

[0077] When the answer is no in ST22, proceed to ST24. In ST24, check whether the number of times Na1 of A1 is, for example, 80% or more of the average number of times Nave. If it is 80 or more, in ST25, increase the predetermined number of times Nset by one. This information will be reflected after the next work start time.

[0078] That is, the stationary control unit monitors the length of one working time, and when it is long, it reduces the predetermined number Nset for the next day, and when it is short, it increases the predetermined number Nset for the next day. This control is implemented by ST22 to ST25, and since the predetermined number Nset is automatically updated, the burden on the manager of the mowing field is reduced. In addition, the burden on the in-vehicle battery is reduced and its life is extended.

[0079] Note that ST22 to ST25 shown in FIG. 12 are only a preferred example, and it is acceptable to change 80% to 90% or 70%. Also, in ST22 to ST25, the length of one working time is monitored based on the number of times Na3 of A3 and the number of times Na1 of A1, but the number of times Na3 of A3 may be replaced with the number of times Na2 of A2, and the number of times Na1 of A1 may be replaced with the number of times Na0 of A0.

[0080] Also, it is acceptable to directly monitor the one working time Tw1 calculated in ST11. Therefore, monitoring the length of one working time is not limited to this embodiment and can be appropriately changed.

[0081] However, the one working time Tw1 varies between the start time of work and the end time of work. When rewriting the predetermined number Nset for the next day, it is preferable to refer to the one working time Tw1 a number of times rather than once in order to achieve leveling. Therefore, FIG. 12 is recommended.

[0082] In addition, although the present invention is suitable for an autonomous control type lawn mower, it can be applied to an autonomous control type turf mower without any problem. Also, the present invention can be applied not only to an autonomous control type lawn mower that travels within an area wire but also to an autonomous control type lawn mower that travels while confirming its position by means such as GPS without an area wire.

[0083] Also, in FIG. 7, the 15 minutes of "+15 minutes" described in ST14 are merely examples, and it is acceptable to change them to 10 minutes or 20 minutes. The 30 minutes of "+30 minutes" described in ST16 can be changed to 20 minutes or 40 minutes. The same applies to FIGS. 10 and 11.

Industrial Applicability

[0084] The present invention is suitable for an autonomous control type lawn mower that performs traveling and mowing using electric energy.

Explanation of Signs

[0085] 10... Autonomous control type lawn mower (lawn mower), 25... Vehicle-mounted battery, 27... Vehicle-mounted control unit, 40... Mowing equipment, 41... Mowing area, 50... Fixed power supply unit, 51... Charging station, 52... Charger, 53... Fixed control unit, A0... Rated charging current, A1 to A3... Small charging currents, Nact... Number of times, Nave... Predetermined number of times, Tave... Scheduled mowing time, Ts... Departure time, Tg... Return time, Tw1... One working time.

Claims

1. An autonomous control type lawn mower equipped with an in-vehicle battery and an in-vehicle control unit, which performs lawn mowing while autonomously traveling using the in-vehicle battery, A lawn mowing facility comprising a stationary control unit and a stationary power supply unit for charging the in-vehicle battery, When the voltage of the in-vehicle battery drops to a predetermined lower limit voltage, the in-vehicle control unit returns the autonomous control type lawn mower to the stationary power supply unit, and when the charging is completed, the in-vehicle control unit controls to start the autonomous control type lawn mower from the stationary power supply unit, The stationary power supply unit is provided with a charger capable of selecting a rated charging current recommended for the in-vehicle battery and a charging current smaller than this rated charging current, The stationary control unit calculates a one-work time from the start time and return time of the autonomous control type lawn mower, and when this one-work time is less than or equal to a pre-stored planned lawn mowing time, selects the rated charging current, When the one-work time exceeds the planned lawn mowing time, the lawn mowing facility is characterized in that charging is performed with the smaller charging current and a smaller charging current corresponding to the excess time is selected.

2. The lawn mowing facility according to Claim 1, The stationary control unit further counts the number of starts in a day, and when this number reaches a predetermined number pre-stored, controls to end the lawn mowing for that day.

3. The lawn mowing facility according to Claim 2, The stationary control unit further monitors the length of the one-work time, and when it is long, reduces the predetermined number for the next day, and when it is short, increases the predetermined number for the next day.

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