WORK ROBOT

Abstract

A working robot can have a working mechanism, a movement mechanism, a working motor, a movement motor, a battery configured to supply power to the working motor and the movement motor, a voltage sensing unit configured to detect a voltage value from the battery, and a control unit. The control unit can be configured to receive a first-stage voltage value detected by the voltage sensing unit while a target motor is running, and then stop the target motor; and to receive a second-stage voltage value detected by the voltage sensing unit while the target motor is not running, and then determine whether or not to return the working robot to a charging station based on the first-stage and second-stage voltage values.The target motor can be at least one of the working motor and the motion motor.

Description

TECHNICAL FIELD

[0001] The technology disclosed herein relates to a work robot. STATE OF THE ART

[0002] JP 2016-10382 A discloses a work robot configured to move and work autonomously. The work robot includes a work mechanism configured to work, a movement mechanism configured to move the work robot, a work motor configured to drive the work mechanism, a movement motor configured to drive the movement mechanism, a rechargeable battery configured to supply power to the work motor and the movement motor, a voltage detection unit configured to detect a voltage value of the battery, and a control unit. The control unit returns the work robot to a charging station when a value detected by the voltage detection unit becomes equal to or less than a predetermined value.The battery of the work robot can be charged when the work robot has been returned to the charging station. SHORT SUMMARY

[0003] If the time to return the work robot to the charging station is too late, the battery may run out on the return path, causing the work robot to stop before reaching the charging station. In this case, the battery cannot be recharged without user assistance, and the work robot cannot work. This prevents the work robot from progressing smoothly. Otherwise, if the time to return the work robot to the charging station is too early, the work robot will be returned to the charging station even if the battery still has sufficient power to allow the work robot to continue working. This also hinders the smooth work progress of the work robot because the work robot's work would be frequently interrupted.The present disclosure provides a technology that enables smooth work progress by a work robot.

[0004] A work robot disclosed herein may be configured to move and work autonomously. The work robot may include a work mechanism configured to work, a movement mechanism configured to move the work robot, a work motor configured to drive the work mechanism, a movement motor configured to drive the movement mechanism, a rechargeable battery configured to supply power to the work motor and the movement motor, a voltage detection unit configured to detect a voltage value of the battery, and a control unit.The control unit may be configured to perform a two-stage detection process in which the control unit obtains a detection value detected by the voltage detection unit while a target motor is operating as a first-stage voltage value, and then the control unit stops the target motor and obtains a detection value detected by the voltage detection unit while the target motor is not operating as a second-stage voltage value, where the target motor is at least one of the working motor and the moving motor. The control unit may be configured to further perform a return determination process in which the control unit determines, based on the first-stage voltage value and the second-stage voltage value, whether or not the working robot should be returned (returned) to the charging station.

[0005] While one or both of the motors are operating, the battery voltage decreases due to the internal resistance of the motor(s), compared to when the motor(s) are not operating. Therefore, in order to specify the correct timing for returning the work robot, it is desirable to obtain detection values ​​from the voltage detection unit for the respective operating states of the motor(s). According to the configuration described above, the control unit of the work robot can obtain detection values ​​from the voltage detection unit for the respective operating states of the motor(s), and thus specify the correct timing for returning the work robot. That is, the configuration described above prevents the timing for returning the work robot from being too late or too early.Thus, the configuration described above can prevent the battery from running out on the return path and prevent the work of the work robot from being frequently interrupted. Therefore, the work of the work robot can progress smoothly. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows an example of use of a robotic lawnmower 2 according to a first embodiment. Fig. 2 shows a left side view of the robotic lawnmower 2 according to the first embodiment. Fig. 3 shows a rear view of the robotic lawnmower 2 according to the first embodiment. Fig. 4 shows a schematic configuration drawing of the robotic lawnmower 2 according to the first embodiment. Fig. 5 shows a flowchart of a battery voltage control process executed by a control unit 8 of the robotic lawnmower 2 according to the first embodiment. Fig. 6 shows a flowchart of a battery voltage control process executed by the control unit 8 of the robotic lawnmower 2 according to the first embodiment. Fig. 7 schematically shows a change in a voltage value of a battery 18 over time in a case where a determination to return to a charging station 110 is made without correcting a return threshold value Vre in the robotic lawnmower 2 according to the first embodiment. Fig. 8 schematically shows a change in a voltage value of the battery 18 over time in a case where the robotic lawnmower 2 according to the first embodiment is returned to the charging station 110 according to the battery voltage control process. Fig. 9 shows a flowchart of a motor burnout prevention process (motor burnout prevention process) executed by the control unit 8 of the robotic lawnmower 2 according to the first embodiment. Fig. 10 shows a schematic configuration drawing of a robotic lawnmower 202 according to a second embodiment. Fig. 11 schematically shows a change in a voltage value of a battery 18 over time in a case where a robotic lawnmower 2 is returned to the charging station 110 according to the battery voltage control process according to a modification. DESCRIPTION

[0006] Representative, non-limiting examples of the present disclosure are described in detail below with reference to the accompanying drawings. This detailed description is merely intended to teach a person skilled in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be used separately or in conjunction with other features and teachings to provide improved work robots and methods of making and using the same.

[0007] Furthermore, combinations of features and steps described in detail below may not be necessary to practice the present disclosure in its broadest sense, and are instead taught merely to specifically describe preferred examples of the present disclosure. Furthermore, various features of the representative examples described above and below, and of the independent and dependent claims, may be combined in ways not specifically and explicitly recited to provide additional useful embodiments of the present teachings.

[0008] All features disclosed in the description and / or claims are intended to be considered separate and independent of each other for the purpose of original disclosure and also for the purpose of limiting the claimed invention, regardless of the combination of features in the embodiments and / or the claims. Furthermore, all ranges or groupings of units are intended to disclose any possible intermediate values ​​or subsets of units for the purpose of original disclosure and also for the purpose of limiting the claimed invention.

[0009] In one or more embodiments, the control unit may be configured to receive a detection value detected by the voltage detection unit as a first determination voltage value. The control unit may be configured to execute the two-stage detection process when the first determination voltage value is less than or equal to a predetermined value. The control unit may be configured not to execute the two-stage detection process when the first determination voltage value is greater than the predetermined value.

[0010] When the battery voltage is high to a certain extent, it is obvious that there is no need to return the work robot without executing the two-stage sensing process. If the two-stage sensing process is executed when the battery voltage is high to a certain extent, the target motor (that is, at least one of the work motor and the movement motor) will be unnecessarily stopped temporarily, which may hinder the smooth progress of the work robot. The above configuration prevents the two-stage sensing process from being executed when the battery voltage is high to a certain extent. Therefore, the above configuration can prevent the target motor from being unnecessarily stopped and thus enable the work to proceed smoothly by the work motor.

[0011] In one or more embodiments, the control unit may store a predetermined return threshold. The control unit may be configured to further execute a threshold correction process in which the control unit corrects the return threshold based on the first-stage voltage value and the second-stage voltage value. The return determination process may include a process in which the control unit obtains a detection value detected by the voltage detection unit as a second determination voltage value and determines whether or not the work robot should be returned to the charging station based on whether the second determination voltage value is less than or equal to a corrected return threshold.

[0012] According to the configuration described above, the control unit determines whether or not to return the work robot to the charging station based not only on the first-stage voltage value and the second-stage voltage value, but also on the predetermined return threshold. Thus, the time to return the work robot to the charging station can be determined more accurately.

[0013] In one or more embodiments, the control unit may be configured to receive a detection value detected by the voltage detection unit as a third determination voltage value. The control unit may be configured to execute the two-stage detection process when the third determination voltage value is less than or equal to the feedback threshold. The control unit may be configured not to execute the two-stage detection process when the third determination voltage value is above the feedback threshold.

[0014] When the battery voltage is high to a certain degree, it is obvious that there is no need to return the work robot without executing the two-stage sensing process. If the two-stage sensing process is executed when the battery voltage is high to a certain degree, the target motor (that is, at least one of the work motor and the movement motor) will be temporarily and unnecessarily stopped, which hinders the smooth progress of the work robot. The above configuration prevents the execution of the two-stage sensing process when the battery voltage is high to a certain degree. Therefore, the above configuration can prevent the target motor from being unnecessarily stopped and thus enables the work robot to progress smoothly.

[0015] In one or more embodiments, in the threshold correction process, the control unit may correct the feedback threshold based on a recovery voltage value obtained by subtracting the first-stage voltage value from the second-stage voltage value.

[0016] The configuration described above allows the feedback threshold to be corrected using a simple configuration.

[0017] In one or more embodiments, in the threshold correction process, the control unit may correct the feedback threshold by subtracting the recovery voltage value from the feedback threshold.

[0018] The target motor can be configured to operate while the work robot is operating and to stop while the work robot is on the return path to the charging station. In this case, when the work robot begins to return after work, the battery voltage value is expected to recover (increase) by an amount equal to the recovery voltage value. Therefore, when deciding whether or not to return the work robot, it is desirable to consider the recovery (recovery) of the battery voltage value by the recovery voltage value. The above configuration considers the recovery (recovery) of the battery voltage value by the recovery voltage value to determine whether or not to return the work robot. Thus, the timing for returning the work robot to the charging station can be determined more accurately.

[0019] In one or more embodiments, in the threshold correction process, when the recovery voltage value is greater than or equal to a predetermined upper limit, the control unit may subtract the upper limit from the feedback threshold instead of subtracting the recovery voltage value from the feedback threshold.

[0020] If a recovery voltage value calculated during the threshold correction process is large (high), the recovery amount of the battery voltage value at the time the work robot starts returning after work may be smaller than the calculated recovery voltage value. In this case, if the correction is made by subtracting the large (high) recovery voltage value from the return threshold, the battery voltage value at the time the work robot starts returning will be smaller than expected. Therefore, the battery may become depleted while the work robot is on the return path.According to the configuration described above, when the recovery voltage value calculated in the threshold correction process is greater than or equal to the upper limit value, a value obtained by subtracting the upper limit value from the return threshold value is used as the corrected return threshold value, instead of a value obtained by subtracting the recovery voltage value from the return threshold value. This prevents the battery voltage value from becoming lower than expected at the time the work robot starts returning. Thus, the configuration can prevent the battery from becoming depleted while the work robot is on the return path.

[0021] In one or more embodiments, in the threshold correction process, when the recovery voltage value is less than or equal to a predetermined lower limit, the control unit may determine the feedback threshold before the correction as the corrected feedback threshold.

[0022] If the two-stage sensing process and the threshold correction process are performed when the battery voltage value has decreased to approximately the return threshold, the resulting recovery voltage value may be small. In this case, even if the target motor (i.e., at least one of the work motor and the movement motor) that was stopped in the two-stage sensing process is restarted by the work motor to resume work, the work robot must start returning shortly thereafter. This means that actions performed by the work robot from resuming work to starting returning do not significantly affect the work progress and may therefore be unnecessary. The work efficiency of the work robot may decrease if the work robot performs unnecessary actions for a long period of time.When the recovery voltage value calculated during the threshold correction process is small, the corrected return threshold is equal to the return threshold before correction. That is, the corrected return threshold is greater than a value obtained by subtracting the recovery voltage value from the return threshold. Therefore, the work robot starts returning earlier, thus performing unnecessary actions for a shorter time. This improves the work efficiency of the work robot.

[0023] In one or more embodiments, one of the working robot and the movement motor may be the target motor. The other of the working motor and the movement motor may be a non-target motor that is not the target motor. The control unit may be configured to perform the two-stage detection process while the non-target motor is not operating.

[0024] The two-stage detection process is a process for observing changes in the battery voltage value caused by changes in the operating state of the target motor. However, the battery voltage value may also change due to the operating state of the non-target motor. Therefore, if the operating state of the non-target motor changes during the two-stage detection process, changes in the battery voltage value caused by changes in the operating state of the target motor cannot be accurately observed (detected). With the configuration described above, the operating state of the non-target motor does not change during the two-stage detection process, and thus the changes in the battery voltage value caused by changes in the operating state of the target motor can be accurately observed.

[0025] In one or more embodiments, the control unit may be configured to perform the feedback determination process while the non-target motor is not operating.

[0026] If the operating state of the non-target motor in the two-stage detection process is different from that in the return determination process, the timing for returning the work robot to the charging station cannot be accurately determined. With the configuration described above, the operating state of the non-target motor is the same in the two-stage detection process and the return determination process, and thus the timing for returning the work robot to the charging station can be accurately determined.

[0027] In one or more embodiments, the control unit may be configured to stop the non-target motor at or after a time when an operating time of the non-target motor reaches a predetermined duration.

[0028] It is desirable that the two-stage detection process (or the return determination process) be repeated at appropriate time intervals until the time to return the work robot is determined. However, in the configuration where the two-stage detection process (or the return determination process) is executed while the non-target motor is not operating, the two-stage detection process (or the return determination process) cannot be executed while the non-target motor is operating. According to the above configuration, the non-target motor is forcibly (mandatorily) stopped at or after the time when the operating time of the non-target motor reaches the predetermined time. Therefore, the two-stage detection process (or the return determination process) can be repeated at appropriate time intervals.

[0029] In one or more embodiments, the working motor may be the target motor. The moving motor may be the non-target motor.

[0030] The work motor is expected to be running (working) while the work robot is working, and not running while the work robot is on the return path to the charging station. Therefore, it is essential to obtain battery voltage values ​​for the respective operating states of the work motor in order to determine the time for returning the work robot. Conversely, the motion motor is expected to essentially continue running (working) while the work robot is working and also while the work robot is on the return path to the charging station. Therefore, it is less necessary to obtain battery voltage values ​​for the respective operating states of the motion motor in order to determine the time for returning the work robot.However, if battery voltage values ​​are obtained for the respective operating states of the motion motor, the processing load on the control unit is unnecessarily increased. According to the configuration described above, battery voltage values ​​are obtained for the respective operating states of the work motor, but battery voltage values ​​are not obtained for the respective operating states of the motion motor. Therefore, the configuration described above can reduce the processing load on the control unit and can also accurately determine the time to return the work robot to the charging station.

[0031] In one or more embodiments, the working mechanism may include a cutting blade configured to mow a lawn. The working robot may function as an autonomously movable robotic mower.

[0032] The configuration described above allows the robotic lawnmower to return to the charging station at the appropriate time. First embodiment

[0033] As in Fig. 1, a working robot according to one embodiment is, for example, a robotic lawnmower 2, which is used within a property 100 on which grass grows. Within the property 100 there is, for example, a house 102, a pond 104, a path 106 and a fence 108. Also located within the property 100 (on the property 100) are a charging station 110 connected to an external power source (e.g., a mains power source), and a wire 112 defining a working area WA for the robotic lawnmower 2. The working area WA here is an area (region) surrounded by the wire 112. The working area WA for the robotic lawnmower 2 is divided into a main area MA, which has the charging station 110, and a secondary area SA, which does not have the charging station 110. The robotic lawnmower 2 can detect the position of the wire 112 and move autonomously in such a way that it leaves the working area WA in which the robotic lawnmower 2 is present (in the example of Fig. 1 does not leave the main area MA). Thus, the robotic lawnmower 2 can mow the lawn while moving across the lawn and avoiding (bypassing, evading) the house 102, the pond 104, the path 106, and the fence 108.

[0034] As in Fig. 2, Fig. 3 and Fig. As shown in Figure 4, the robotic lawnmower 2 includes a robot body 4, a power supply unit 6, a control unit 8, an operating unit 10, a movement unit 12, a working unit 14, and a detection unit 16. The power supply unit 6, the control unit 8, the operating unit 10, the movement unit 12, the working unit 14, and the detection unit 16 are each supported by the robot body 4.

[0035] The power supply unit 6, which is Fig. 4, is configured to supply electrical power to each unit of the robotic lawnmower 2 via a power supply circuit 26 of the control unit 8. The power supply unit 6 comprises a rechargeable battery 18, such as a lithium-ion battery, and a charging interface 20 electrically connected to the battery 18. The nominal capacity of the battery 18 is, for example, 5.0 Ah. The nominal voltage of the battery 18 is, for example, 18 V. The robotic lawnmower 2 is configured to be connected to the charging station 110 (see Fig. 1) via the charging interface 20. When the robotic lawnmower 2 is docked to the charging station 110, the battery 18 is recharged with electrical power supplied from the charging station 110. The method for charging the battery 18 can be a wired charging method. In particular, a terminal of the charging station 110 and a terminal of the charging interface 20 can be connected to each other to charge the battery 18. Alternatively, the method for charging the battery 18 can be a wireless charging method. In particular, a transmitting coil of the charging station 110 can generate an induced electromagnetic force in a receiving coil of the charging interface 20 to charge the battery 18.

[0036] The control unit 8 comprises a processor 22, a memory 24, and the power supply circuit 26. The memory 24 comprises a ROM, a RAM, etc. A program for autonomously controlling the robotic lawnmower 2 is stored in the memory 24. The processor 22 is configured to autonomously control the robotic lawnmower 2 according to the program in the memory 24. Specifications regarding the robotic lawnmower 2 (e.g., a height of the lawn after mowing) are also stored in the memory 24. The specifications regarding the robotic lawnmower 2 include a specification regarding an operating mode of the robotic lawnmower 2. The operating mode of the robotic lawnmower 2 is selectively set to one of several modes, including a main area mode for the main area MA (see Fig. 1) and a secondary area mode for the secondary area SA (see Fig. 1).

[0037] The actuating unit 10 is located, for example, on an outer surface of the robot body 4 (see Fig. 2) and includes a switch configured to be (manually) operated by a user, etc. The user can perform various operations on the robotic lawnmower 2 via the operation unit 10. The various operations include, for example, turning the main power of the robotic lawnmower 2 on / off, inputting commands to the robotic lawnmower 2, changing a setting related to the robotic lawnmower 2, etc.

[0038] The movement unit 12 includes a pair of left and right rollers 28L, 28R, a pair of left and right drive wheels 30L, 30R, and a pair of left and right movement motors 32L, 32R. The movement motors 32L, 32R are, for example, brushless DC motors. The drive wheels 30L, 30R are respectively coupled to the output shafts of the movement motors 32L, 32R. As shown in Fig. 2 and Fig. 3, the robotic lawnmower 2 is placed on a ground G, with the rollers 28L, 28R and the drive wheels 30L, 30R touching the ground G. By the movement motors 32L, 32R (see Fig. 4) the drive wheels 30L, 30R rotate, the movement unit 12 can move the robot body 4 forward, move the robot body 4 backward and rotate the robot body 4.

[0039] As in Fig. As shown in Figure 2, the working unit 14 includes a blade (cutting blade) 34 and a working motor 36. The blade 34 is a substantially disc-shaped rotating blade. The working motor 36 is, for example, a brushless DC motor. The working motor 36 is supported by the robot body 4 such that the upper end of its output shaft is located in front of the lower end thereof. The blade 34 is coupled to the output shaft of the working motor 36. The working unit 14 can mow the lawn by driving the working motor 36 to rotate the blade 34.

[0040] As in Fig. 4, the detection unit 16 includes a wire detection sensor 38, a motor current detection circuit 40, and a battery voltage detection circuit 42.

[0041] The wire detection sensor 38 is a sensor for detecting the wire 112 (see Fig. 1). The wire detection sensor 38 is, for example, a magnetic sensor. In this embodiment, the charging station 110 (see Fig. 1) applies a predetermined electrical signal to the wire 112, thereby generating a magnetic signal corresponding to the predetermined electrical signal around the wire 112. The wire detection sensor 38 is configured to detect this magnetic signal and output it to the processor 22. Based on the signal pattern and / or the signal strength of the magnetic signal detected by the wire detection sensor 38, the processor 22 can determine whether the robotic lawnmower 2 is approaching the wire 112, whether the robotic lawnmower 2 is on the wire 112, etc.

[0042] The motor current detection circuit 40 is configured to detect current values ​​supplied to the movement motors 32L, 32R and the working motor 36 and output them to the processor 22.

[0043] The battery voltage detection circuit 42 is configured to detect a voltage value of the battery 18 and output it to the processor 22. The processor 22 can thus obtain the voltage value of the battery 18.

[0044] The following describes operations and / or processes performed by the control unit 8 (in particular the processor 22). Mowing process

[0045] A mowing operation is the main operation (main working process) of the robotic lawnmower 2 (see Fig. 1). The mowing process is started, for example, when the robotic lawnmower 2 is switched on and a command to start the mowing process is sent via the operating unit 10 (see Fig. 4). When the mowing process is started, the control unit 8 confirms that the robotic lawnmower 2 has no abnormalities and then causes the robotic lawnmower 2 to start mowing. This means that the control unit 8 activates the blade 34 (see Fig. 2) by the working motor 36 and activates the drive wheels 30L, 30R (see Fig. 2) by the movement motors 32L, 32R (see Fig. 4) to cause the robotic lawnmower 2 to mow. During the mowing process, the control unit 8 can cause the robotic lawnmower 2 to pause or stop mowing, depending on the circumstances and due to other actions. The control unit 8 stops the mowing process when a predetermined operation termination condition (operation termination condition) is met. The operation termination condition herein includes, for example, a period of time from the start of the mowing process reaching a period of time specified by the user. Battery voltage management process; FIGS. 5 and 6

[0046] A battery voltage management process is repeated while the mowing process described above is carried out by the robotic lawnmower 2 (see Fig. 2) is executed in the main area mode. The battery voltage management process is a process for returning the robotic lawnmower 2 to the charging station 110 (see Fig. 1) to charge the battery 18 (see Fig. 4) when the voltage value of the battery 18 is (becomes) low. A voltage value of the battery 18 required to return the robotic lawnmower 2 to the charging station 110 (return threshold value Vre) is stored in advance in the memory 24 (see Fig. 4). In this embodiment, the return threshold Vre is set to 17.5 V. The battery voltage management process mainly includes a process for correcting the return threshold Vre and a process for returning the robotic lawnmower 2 to the charging station 110 based on the corrected return threshold Vre'.

[0047] As in Fig. As shown in Figure 5, the control unit 8 determines whether a correction flag is on (set) in S2. The correction flag is a status register contained in the memory 24. If the corrected feedback threshold value Vre' has not yet been obtained, the correction flag is off. If the correction flag is off (NO in S2), the process proceeds to S4.

[0048] In S4, the control unit 8 determines whether the movement motors 32L, 32R (see Fig. 4) are not in operation. The motion motors 32L, 32R are generally in operation while the robotic lawnmower 2 is mowing. However, the motion motors 32L, 32R can stop, for example, when the robotic lawnmower 2 is turning. If the motion motors 32L, 32R are in operation (NO in S4), the process continues with S6.

[0049] In S6, the control unit 8 determines whether the operating time of the movement motors 32L, 32R is equal to or greater than a first upper limit duration (e.g., two minutes). The operating time of the movement motors 32L, 32R herein means a time elapsed since the start of the last operation of the movement motors 32L, 32R. If the operating time of the movement motors 32L, 32R is less than the first upper limit duration (NO in S6), the process returns to S2. If the operating time of the movement motors 32L, 32R is equal to or greater than the first upper limit duration (YES in S6), the process proceeds to S8.

[0050] In S8, the control unit 8 stops the movement motors 32L, 32R.

[0051] If it is determined that the movement motors 32L, 32R are not operating in S4 (YES in S4) or after S8, the process proceeds to S10. In S10, the control unit 8 receives a value determined by the battery voltage detection circuit 42 (see Fig. 4) as a determination voltage value, and determines whether the obtained determination voltage value is equal to or less than the feedback threshold Vre. While the robotic lawnmower 2 is moving, the working motor 36 stops (see Fig. 4) is fundamentally not possible. Therefore, the determination voltage value obtained in S10 is a voltage value of the battery 18 while the working motor 36 is operating and the moving motors 32L, 32R are not operating. If the determination voltage value is greater than the feedback threshold Vre (NO in S10), the process returns to S2. In a case of NO in S10, after the moving motors 32L, 32R are stopped in S8, the control unit 8 restarts the moving motors 32L, 32R. If the determination voltage value is equal to or greater than the feedback threshold Vre (YES in S10), the process proceeds to S12.

[0052] In S12, the control unit 8 obtains a value detected by the battery voltage detection circuit 42 as a first-stage voltage value V1. The first-stage voltage value V1 obtained in S12 is a voltage value of the battery 18 while the working motor 36 is operating and the moving motors 32L, 32R are not operating. After S12, the process proceeds to S14.

[0053] In S14, the control unit 8 stops the working motor 36. That is, the control unit 8 causes the robotic lawnmower 2 to pause mowing. The control unit 8 then waits for a predetermined period of time (e.g., 2 seconds) after the working motor 36 stops. Consequently, the voltage value of the battery 18 recovers by an amount of voltage drop in the working motor 36 due to its internal resistance, compared to the voltage value of the battery 18 immediately before the mowing operation was suspended (interrupted). After S14, the process continues with S16.

[0054] In S16, the control unit 8 obtains a value detected by the battery voltage detection circuit 42 as a second-stage voltage value V2 while mowing by the robotic lawnmower 2 is suspended (interrupted). The second-stage voltage value V2 obtained in S16 is a voltage value of the battery 18 while the working motor 36 and the moving motors 32L, 32R are not operating. After obtaining the second-stage voltage value V2, the control unit 8 restarts the moving motors 32L, 32R and the working motor 36 to resume mowing by the robotic lawnmower 2. After S16, the process proceeds to S18.

[0055] In S18, the control unit 8 calculates a recovery voltage value Vdiff by subtracting the first-stage voltage value V1 from the second-stage voltage value V2. That is, the recovery voltage value Vdiff = V2 - V1. After S18, the process continues with S20.

[0056] In S20, the control unit 8 determines whether the recovery voltage value Vdiff calculated in S18 is equal to or less than a predetermined lower limit (e.g., 0.1 V). If the recovery voltage value Vdiff is equal to or less than the lower limit (YES in S20), the process proceeds to S22.

[0057] In S22, the control unit 8 sets the recovery voltage value Vdiff to 0 V.

[0058] If it is determined that the recovery voltage value Vdiff is greater than the lower limit value in S20 (NO in S20), the process proceeds to S24. In S24, the control unit 8 determines whether the recovery voltage value Vdiff calculated in S18 is equal to or greater than a predetermined upper limit value (e.g., 0.5 V). If the recovery voltage value Vdiff is equal to or greater than the upper limit value (YES in S24), the process proceeds to S26.

[0059] In S26, the control unit 8 sets the recovery voltage value Vdiff to a value equal to the upper limit used for the determination in S24 (e.g., 0.5 V).

[0060] If it is determined that the recovery voltage value Vdiff is less than the upper limit value in S24 (NO in S24), after S22 or after S26, the process proceeds to S28. In S28, the control unit 8 corrects the feedback threshold Vre by subtracting the recovery voltage value Vdiff from the feedback threshold Vre. That is, the corrected feedback threshold Vre' = Vre - Vdiff. Further, the control unit 8 stores the corrected feedback threshold Vre' in the memory 24 and changes the correction flag to on. After S28, the process returns to S2.

[0061] If it is determined that the correction flag is on in S2 (YES in S2), the process continues with S30 which is in Fig. 6. In S30, the control unit 8 determines whether the movement motors 32L, 32R are not operating. If the movement motors 32L, 32R are operating (NO in S30), the process proceeds to S32.

[0062] In S32, the control unit 8 determines whether the operating time of the movement motors 32L, 32R is equal to or greater than a second upper limit time (e.g., one (1) minute). If the operating time of the movement motors 32L, 32R is less than the second upper limit time (NO in S32), the process returns to S2 (see Fig. 5). If the operating time of the motion motors 32L, 32R is equal to or greater than the second upper limit time (YES in S32), the process proceeds to S34.

[0063] In S34, the control unit 8 stops the movement motors 32L, 32R.

[0064] If it is determined that the movement motors 32L, 32R are not operating in S30 (YES in S30), or after S34, the process proceeds to S36. In S36, the control unit 8 obtains a value detected by the battery voltage detection circuit 42 as a determination voltage value and determines whether the obtained determination voltage value is equal to or less than the corrected feedback threshold value Vre'. The determination threshold value obtained in S36 is a voltage value of the battery 18 while the working motor 36 is operating and the movement motors 32L, 32R are not operating. If the determination voltage value is greater than the corrected feedback threshold value Vre' (NO in S36), the process returns to S2 (see Fig. 5). If NO in S36, after the movement motors 32L, 32R are stopped in S34, the control unit 8 restarts the movement motors 32L, 32R. If the determination voltage value is equal to or less than the corrected feedback threshold value Vre' (YES in S36), the process proceeds to S38.

[0065] In S38, the control unit 8 causes the robotic lawnmower 2 to stop mowing and returns the robotic lawnmower 2 to the charging station 110. Specifically, the control unit 8 stops the working motor 36 and controls the movement motors 32L, 32R to guide the robotic lawnmower 2 along the wire 112 to the charging station 110. After S38, the process continues with S40.

[0066] In S40, the control unit 8 causes the robotic lawnmower 2 to dock at the charging station 110 to start charging the battery 18. Further, in response to the robotic lawnmower 2 docking at the charging station 110, the control unit 8 deletes the corrected feedback threshold Vre' from the memory 24 and changes the correction flag to off. Note that the correct feedback threshold Vre' stored in the memory 24 is deleted from the memory 24 even if the robotic lawnmower 2 docks at the charging station 110 regardless of S40 of the battery voltage control process. Note that the correction flag is changed to off even if the robotic lawnmower 2 docks at the charging station 110 regardless of S40 of the battery voltage control process. After S40, the process continues with S42.

[0067] In S42, the control unit 8 determines whether a predetermined normal resumption condition is met. The normal resumption condition includes, for example, that the voltage value of the battery 18, detected by the battery voltage detection circuit 42, is equal to or greater than a predetermined value (e.g., 20 V). If the normal resumption condition is not met (NO in S42), S42 is repeated. If the normal resumption condition is met (YES in S42), the process proceeds to S44.

[0068] In S44, the control unit 8 stops charging the battery 18, uncouples the robotic lawnmower 2 from the charging station 110, and restarts the movement motors 32L, 32R and the working motor 36. This means that the control unit 8 causes the robotic lawnmower 2 to resume mowing. After S44, the battery voltage control process ends, which is carried out in Fig. 5 and Fig. 6 is shown. Advantages of the battery voltage control process

[0069] The robotic lawnmower 2 stops driving the working motor 36 (see Fig. 4) upright while mowing, whereas it keeps the working motor 36 stationary while returning to the charging station 110 (see Fig. 1) stops. This means that when the robotic lawnmower 2 stops mowing and starts returning, the voltage value of the battery 18 recovers (see Fig. 4) by an amount of voltage drop in the working motor 36 caused by its internal resistance. When the robotic lawnmower 2 starts returning at the time when the voltage value of the battery 18 becomes equal to the return threshold value Vre during mowing by the robotic lawnmower 2, the voltage value of the battery 18 soon recovers and significantly exceeds the return threshold value Vre, as shown in Fig. 7. That is, the robotic lawnmower 2 returns to the charging station 110 even though the battery 18 still has sufficient power to allow the robotic lawnmower 2 to continue mowing. Since the robotic lawnmower 2 must frequently return to the charging station 110, the proportion of time during which the robotic lawnmower 2 is not mowing (e.g., the time during which the robotic lawnmower 2 returns (is returned) to the charging station 110, the time during which the battery 18 is charged, etc.) is relatively large compared to the proportion of time during which the robotic lawnmower 2 is mowing. Therefore, the working efficiency of the robotic lawnmower 2 may be reduced.

[0070] As in Fig. As shown in Figure 8, in the battery voltage management process, the voltage drop at the working motor 36 caused by its internal resistance is determined as the recovery voltage value Vdiff. Then, the return threshold Vre' is obtained by subtracting the recovery voltage value Vdiff from the (pre)set return threshold Vre. The robotic lawnmower 2 starts returning at the time when the voltage value of the battery 18 becomes equal to the return threshold Vre' during mowing by the robotic lawnmower 2. Immediately after the robotic lawnmower 2 starts returning, the voltage value of the battery 18 recovers (increases) to a value around the return threshold Vre. Thus, the robotic lawnmower 2 starts returning to the charging station 110 at the time when the voltage of the battery 18 is so low that the robotic lawnmower 2 can no longer continue mowing.This allows the robotic lawnmower 2 to be returned to the charging station 110 as infrequently as possible, and thus the proportion of time during which the robotic lawnmower 2 is not mowing can be relatively small compared to the proportion of time during which the robotic lawnmower 2 is mowing. Therefore, the working efficiency of the robotic lawnmower 2 can be improved. Engine burnout prevention process: FIG. 9

[0071] An engine burnout prevention process is carried out during the mowing process described above, regardless of the operating mode of the robotic lawnmower 2 (see Fig. 1) is repeated. Note that the motor burnout prevention process is also executed during the confirmation that the robotic lawnmower 2 has no abnormality, which occurs before the robotic lawnmower 2 starts mowing.

[0072] In S52, the control unit 8 determines whether the working motor 36 (see Fig. 2) is overheated. Here, “the working motor is overheated” means that the working motor 36 is at an excessively high temperature (e.g., over 150°C), that the working motor 36 is at a temperature that could cause the working motor 36 to burn out (cause a short circuit by melting the coating of a wire), or that the working motor 36 is at a temperature that could affect the service life of the working motor 36. For example, when a value detected by the motor current detection circuit 40 (see Fig. 4) is detected (i.e., the current supplied to the working motor 36), a first current value (e.g., 5 A) or greater remains for a first period of time (e.g., 55 minutes or longer), the control unit 8 assumes that the working motor 36 is at an excessively high temperature and thus determines that the working motor 36 is overheated. Likewise, if a value detected by the motor current detection circuit 40, a second current value (e.g., 6 A) or greater, which is higher than the first current value, remains for a second period of time (e.g., 22 minutes) or longer, which is shorter than the first period of time, the control unit 8 determines that the working motor 36 is overheated. Furthermore, if a value detected by the motor current detection circuit 40, a third current value (e.g., 7 A), which is higher than the second current value, remains for a third period of time (e.g.,If the working motor 36 remains in the working state for a time (e.g., 10 minutes) or longer, which is shorter than the second time period, the control unit 8 determines that the working motor 36 is overheated. If the working motor 36 is overheated (YES in S52), the process proceeds to S54.

[0073] In S54, the control unit 8 determines whether the robotic lawnmower 2 is within the main area MA (see Fig. 1). If the operating mode of the robotic lawnmower 2 is the main area mode, the control unit 8 determines that the robotic lawnmower 2 is within the main area MA (YES in S54). If the operating mode of the robotic lawnmower 2 is different from the main area mode, the control unit 8 determines that the robotic lawnmower 2 is not within the main area MA (NO in S54). If the robotic lawnmower 2 is within the main area MA (YES in S54), the process proceeds to S56.

[0074] In S56, the control unit 8 guides the robotic lawnmower 2 to the charging station 110 (see Fig. 1). In particular, the control unit 8 controls the movement motors 32L, 32R (see Fig. 4) to move the robotic lawnmower 2 along the wire 112 to the charging station 110 while the working motor 36 is not running. Furthermore, the control unit 8 actuates a lighting device and / or a buzzer (not shown) located in / on the robot body 4 to inform, via a sound and / or light, that the abnormality has occurred. After S56, the process continues with S58.

[0075] In S58, the control unit 8 causes the robotic lawnmower 2 to connect to the charging station 110 to start charging the battery 18 (see Fig. 4). Even after charging of the battery 18 has started, the control unit 8 continues to inform about the occurrence of the abnormality. After S58, the process continues with S60.

[0076] In S60, the control unit 8 determines whether a predetermined first abnormal resumption condition is met. In this embodiment, the first abnormal resumption condition includes a condition that the temperature of the working motor 36 is expected to be a normal temperature (e.g., 40 degrees or lower). For example, the first abnormal resumption condition includes a condition that the voltage value of the battery 18 detected by the battery voltage detection circuit 42 (see Fig. 4) is detected reaches a predetermined value (e.g., 20 V) or greater. This is because it is assumed that the temperature of the working motor 36 drops to the normal temperature while the battery 18 is being charged for a certain period of time. Furthermore, the first abnormal resumption condition includes that a period of time elapsed since the determination in the last S52 that the working motor 36 is overheated reaches a predetermined period of time (e.g., 20 minutes). If the first abnormal resumption condition is not satisfied (NO in S60), S60 is repeated. If the first abnormal resumption condition is satisfied (YES in S60), the process proceeds to S62.

[0077] In S62, the control unit 8 stops charging the battery 18, disconnects the robotic lawnmower 2 from the charging station 110, and restarts the movement motors 32L, 32R and the working motor 36. That is, the control unit 8 causes the robotic lawnmower 2 to resume mowing. Furthermore, the control unit 8 stops the operation of the lighting device and / or the buzzer (not shown) to stop the abnormality notification.

[0078] If it is determined in S54 that the robotic lawnmower 2 is not within the main area MA (NO in S54), the process proceeds to S64. In S64, the control unit 8 stops the working motor 36 and the movement motors 32L, 32R to cause the robotic lawnmower 2 to stop (stand still) in place. Furthermore, the control unit 8 actuates the lighting device and / or buzzer (not shown) located in / on the robot body 4 to inform via a sound and / or light that the abnormality has occurred. After S64, the process proceeds to S66.

[0079] In S66, the control unit 8 determines whether a second abnormal resumption condition is met. In this embodiment, the second abnormal resumption condition includes conditions that the temperature of the working motor 36 is expected to be the normal temperature (e.g., 40 degrees or lower). For example, the second abnormal resumption condition includes that a period of time elapsed since the determination in the last S52 that the working motor 36 is overheated reaches a predetermined period of time (e.g., 20 minutes). If the second abnormal resumption condition is not met (NO in S66), S66 is repeated. Thus, if the second abnormal resumption condition is not met, the robotic lawnmower 2 stops in place. If the second abnormal resumption condition is met (YES in S66), the process proceeds to S68.

[0080] In S68, the control unit 8 starts the movement motors 32L, 32R, and the working motor 36 to stop the robotic lawnmower 2 from stopping. That is, the control unit 8 causes the robotic lawnmower 2 to resume mowing. Furthermore, the control unit 8 stops the operation of the lighting device and / or the buzzer (not shown) to stop the abnormality notification.

[0081] If it is determined that the working motor 36 is not overheated in S52 (NO in S52), after S62 or after S68, the motor burnout prevention process executed in Fig. 9 is shown. Second embodiment

[0082] As in Fig. As shown in Figure 10, a robotic lawnmower 202 according to this embodiment has predominantly the same components as those of the robotic lawnmower 2 according to the first embodiment. The common components between the robotic lawnmower 2 and the robotic lawnmower 202 are denoted by the same reference numerals, and a description thereof will be omitted.

[0083] The robotic lawnmower 202 has a detection unit 204 instead of the detection unit 16 (see Fig. 4) of the first embodiment. The detection unit 204 differs from the detection unit 16 in that the former includes a motor temperature sensor 206. The motor temperature sensor 206 is configured to detect a temperature of the working motor 36 and output it to the processor 22 of the control unit 8. Here, the temperature of the working motor 36 includes, for example, a temperature of the stator of the working motor 36, a temperature of a Hall sensor in the working motor 36, and a temperature of a motor drive substrate that controls the rotation of the working motor 36.

[0084] In this embodiment, the control unit 8 determines in S52 of the engine burnout prevention process executed in Fig. As shown in Figure 9, the working motor 36 is overheated when the temperature of the working motor 36 detected by the motor temperature sensor 206 is extremely high (e.g., 150 degrees or higher). Likewise, the first abnormal resumption condition used in S60 of the motor burnout prevention process further includes that the temperature of the working motor 36 detected by the motor temperature sensor 206 is the normal temperature (e.g., 40 degrees or lower). Furthermore, the second abnormal resumption condition used in S66 of the motor burnout prevention process further includes that the temperature of the working motor 36 detected by the motor temperature sensor 206 is the normal temperature (e.g., 40 degrees or lower). Variations

[0085] The working robot may be a different robot than the mowing robots 2, 202. For example, the working robot may be a cleaning robot having a brush for collecting dirt, such as dust, and / or a suction mechanism. In this case, the working motor 36 may be used as a motor for driving the brush and / or the suction mechanism. Alternatively, the working robot may be a rebar tying robot having a rebar tying mechanism configured to tie a plurality of rebars at their intersection points. In this case, the working motor 36 may be used as a motor for driving the rebar tying mechanism.

[0086] At least one of the working motor 36 and the moving motors 32L, 32R may be a motor other than a brushless DC motor (e.g., a brushed DC motor).

[0087] The moving unit 12 may include a pair of left and right crawlers instead of the track rollers 28L, 28R and the drive wheels 30L, 30R. The moving motors 32L, 32R may be used as the motors for driving the pair of left and right crawlers.

[0088] Battery 18 may be a rechargeable battery other than a lithium-ion battery (e.g., a nickel-metal hydride battery, a nickel-cadmium battery). The nominal capacity and voltage of battery 18 may be varied as necessary. The nominal capacity of battery 18 may be, for example, 3.0 Ah. The nominal voltage of battery 18 may be, for example, 36 V.

[0089] The settings for the feedback threshold Vre can be varied as necessary. The settings for the feedback threshold Vre can be changeable or non-changeable by the user via the operating unit 10.

[0090] In the battery voltage control process, which is Fig. 5 and Fig. 6, the control unit 8 may skip S10 to S8 and then execute S12. That is, the control unit 8 may be configured to execute the sequence from S12 to S8, regardless of how much power is still present (remaining) in the battery 18.

[0091] In the determination of S10 in the battery voltage control process, the control unit 8 may use a threshold value Vth (e.g., Vth = 17.6 V) that is different from the feedback threshold value Vre. That is, in S10, the control unit 8 obtains a value detected by the battery voltage detection circuit 42 as the determination voltage value, and may determine whether the obtained determination voltage value is equal to or less than the threshold value Vth. In this example, as shown in Fig. 11, the voltage drop in the working motor 36 caused by its internal resistance is also determined as the recovery voltage value Vdiff. Since the recovery threshold Vre' is determined in almost the same manner as in the embodiment, the voltage value of the battery 18 recovers (increases) to a value close to the recovery threshold Vre immediately after the robotic lawnmowers 2, 202 start returning. Therefore, the robotic lawnmowers 2, 202 can start returning to the charging station 110 with a moderate amount of remaining power in the battery 18.

[0092] In the battery voltage control process, which is Fig. 5 and Fig. 6, the control unit 8 may skip S24 after a NO in S20 and then execute S28. Consequently, the recovery voltage value Vdiff may exceed the upper limit value. Alternatively, the control unit 8 may skip S20 to S18 and then execute S24. Consequently, the recovery voltage value Vdiff may be equal to or less than the lower limit value (which is greater than zero). Alternatively, the control unit 8 may skip S20, S22, S24, S26 to S18 and then execute S28. Consequently, the recovery voltage value Vdiff may exceed the upper limit value and may also be equal to or less than the lower limit value (which is greater than zero).

[0093] In S28 of the battery voltage control process, the control unit 8 can obtain the recovery threshold Vre by subtracting a value obtained by multiplying the recovery voltage value Vdiff by a predetermined coefficient k (e.g., k = 0.8) from the recovery threshold Vre. Thus, Vre' can be represented as Vre' = Vre - k × Vdiff.

[0094] In the battery voltage management process, the control unit 8 may determine whether the robotic lawnmower 2 should be returned to the charging station 110 without calculating the recovery voltage value Vdiff or correcting the return threshold value Vre. For example, after obtaining the first-stage voltage value V1 in S12 and the second-stage voltage value V2 in S16, the control unit 8 may determine whether a value detected by the battery voltage detection circuit 42 (determination voltage value) is equal to or less than a value obtained by 2 × V1 - V2. If the determination voltage value is equal to or less than the value obtained by 2 × V1 - V2 (in the case of YES), the control unit 8 may execute the sequence from S38 onward.If the determination voltage value exceeds the value obtained by 2 × V1 - V2 (in the case of NO), the control unit 8 can restart the battery voltage management process. In this example, the correction flag can always be on.

[0095] In the battery voltage management process, the control unit 8 can skip S4, S6, S8 after a NO in S2 and then execute S10. In this case, the sequence from S10 onward with the motion motors 32L, 32R cannot be stopped (i.e., while the motion motors 32L, 32R are operating). However, it is preferable that the operating state of the motion motors 32L, 32R (operating / not operating) is not changed while S10, S12, S14, S16 are being executed.

[0096] In the battery voltage management process, the control unit 8 can skip S30, S32, S34 after a YES in S2 and then execute S36. In this case, the sequence from S36 onward with the motion motors 32L, 32R cannot be stopped (i.e., while the motion motors 32L, 32R are operating).

[0097] In the first and second embodiments, in S12, S14, S16 of the battery voltage management process, the control unit 8 stops the working motor 36 and observes changes in the voltage value of the battery 18. That is, the working motor 36 corresponds to the target motor in the claims, and the moving motors 32L, 32R correspond to the non-target motors in the claims. In another embodiment, in S12, S14, S16, the control unit 8 may stop the working motor 36 and the moving motors 32L, 32R and observe changes in the voltage value of the battery 18. That is, each (all) of the working motor 36 and the moving motors 32L, 32R may be non-target motors. In yet another embodiment, in S12, S14, S16, the control unit 8 may stop the moving motors 32L, 32R and observe changes in the voltage value of the battery 18.That is, the movement motors 32L, 32R may be the target motors, and the working motor 36 may be the non-target motor.

[0098] After starting the charging of the battery 18 in S58 of the engine burnout prevention process, which is Fig. As shown in Figure 9, the control unit 8 may terminate the motor burnout prevention process and terminate the subsequent mowing instead of executing the sequence from S60. After that, the control unit 8 may terminate charging of the battery 18, for example, when the battery 18 is fully charged, and keep the robotic lawnmowers 2, 202 in the charging station 110. That is, the control unit 8 does not need to cause the robotic lawnmowers 2, 202 to resume mowing after the abnormality (overheating of the working motor 36) has occurred in the robotic lawnmowers 2, 202.

[0099] Abnormalities detected by the detection units 16, 204 are not limited to overheating of the working motor 36 and may include various abnormalities related to the working unit 14. Here, abnormalities related to the working unit 14 include, for example, excessive load on the working motor 36, wear of the blade 34 so severe that the blade 34 needs to be replaced, etc. When an abnormality related to the working unit 14 is detected by the detection unit 16, 204, the control unit 8 may execute the sequence from S54 onward in the motor burnout prevention process. Thus, when an abnormality related to the working unit 14 occurs, the user may be notified of the abnormality, the robotic lawnmowers 2, 202 may be returned to the charging station 110, or the robotic lawnmowers 2, 202 may stop in place.

[0100] The first abnormal resumption condition (or the second abnormal resumption condition) may include a condition that a value detected by the motor current detection circuit 40 (ie, current supplied to the working motor 36) remains equal to or less than a predetermined value for a predetermined period of time or longer.

[0101] The operating mode of the robotic lawnmowers 2, 202 can be automatically changed independently of user operation. For example, the control unit 8 can use GPS to specify the working area WA in which the robotic lawnmowers 2, 202 mow, and change the operating mode of the robotic lawnmowers 2, 202 to a mode corresponding to the specific working area WA. Alternatively, the control unit 8 can store map information of the working area WA in advance and specify the working area WA in which the robotic lawnmowers 2, 202 mow based on the map information.

[0102] The detection units 16, 204 can detect various abnormalities other than those mentioned above. For example, the detection units 16, 204 can detect that the robot body 4 has rolled over (tipped over) and / or that the robot body 4 has been lifted by someone. When these abnormalities are detected by the detection units 16, 204, the control unit 8 can notify the user of the occurrence of the abnormalities using the buzzer (not shown) located in / on the robot body 4. Features of embodiments

[0103] In one or more embodiments, the robotic mowers 2, 202 (examples of a working robot) can move and work autonomously. The robotic lawnmowers 2, 202 include the blade 34 (an example of a working mechanism) configured to work, the drive wheels 30L, 30R (an example of a moving mechanism) configured to move the robotic lawnmowers 2, 202, the working motor 36 configured to drive the blade 34, the moving motors 32L, 32R configured to drive the drive wheels 30L, 30R, the battery 18 that is rechargeable and configured to supply power to the working motor 36 and the moving motors 32L, 32R, the battery voltage detection circuit 42 (an example of a voltage detection unit) configured to detect a voltage value of the battery 18, and the control unit 8.The control unit 8 is configured to perform a two-stage detection process (see S12, S14, S16 in . Fig. 5), in which the control unit 8 obtains a detection value detected by the battery voltage detection circuit 42 while the working motor 36 (an example of a target motor) is operating as the first-stage voltage value V1, and then the control unit 8 stops the working motor 36 and obtains a detection value detected by the battery voltage detection circuit 42 while the working motor 36 is not operating as the second-stage voltage value V2. The control unit 8 is configured to further perform the feedback determination process (see S36 in Fig. 6), in which the control unit 8 determines whether the robotic lawnmowers 2, 202 are to be returned to the charging station 110 or not based on the first-stage voltage value and the second-stage voltage value.

[0104] While the working motor 36 is operating, the voltage value of the battery 18 decreases due to the internal resistance of the working motor 36, compared to when the working motor 36 is not operating. Thus, in order to specify the correct timing for returning the robotic lawnmowers 2, 202, it is desirable to obtain detection values ​​from the battery voltage detection circuit 42 for the respective operating states of the working motor 36. According to the above-described configuration, the control unit 8 of the robotic lawnmowers 2, 202 can obtain detection values ​​from the battery voltage detection circuit 42 for the respective operating states of the working motor 36 and can thus specify the correct timing for returning the robotic lawnmowers 2, 202. That is, the above-described configuration prevents the timing for returning the robotic lawnmowers 2, 202 from being too late or too early.Thus, the configuration described above can prevent the battery 18 from running out when the robotic lawnmowers 2, 202 are on their return path and prevent the work of the robotic lawnmowers 2, 202 from being frequently interrupted. Therefore, the work of the robotic lawnmowers 2, 202 can continue smoothly.

[0105] In one or more embodiments, the control unit 8 may be configured to receive a detection value detected by the battery voltage detection circuit 42 as a (first) determination voltage value. The control unit 8 is configured to execute the two-stage detection process when the (first) determination voltage value is less than or equal to the feedback threshold Vre (or the threshold Vth) (an example of a predetermined value). The control unit 8 is configured not to execute the two-stage detection process when the (first) determination voltage value is above the feedback threshold Vre (or the threshold Vth).

[0106] When a value detected by the battery voltage detection circuit 42 is high to a certain degree, it is obvious that there is no need to return the robotic lawnmowers 2, 202 without executing the two-stage detection process. If the two-stage detection process is executed when the voltage value of the battery 18 is high to a certain degree, the working motor 36 is temporarily stopped unnecessarily, thereby hindering the smooth progress of the work by the robotic lawnmowers 2, 202. According to the above-described configuration, the control unit 8 is configured not to execute the two-stage detection process when the voltage value of the battery 18 is high to a certain degree. Therefore, the above-described configuration can prevent the working motor 36 from being stopped unnecessarily, thus enabling the work by the robotic lawnmowers 2, 202 to progress smoothly.

[0107] In one or more embodiments, the control unit 8 stores the predetermined feedback threshold Vre. The control unit 8 is configured to further execute the threshold correction process (see S18 to S28 in Fig. 5), in which the control unit 8 corrects the feedback threshold value Vre based on the first-stage voltage value V1 and the second-stage voltage value V2. The feedback determination process instructs the process (see S36 in Fig. 6), in which the control unit 8 receives a value detected by the battery voltage detection circuit 42 as a (second) determination voltage value, and determines whether or not the robotic lawnmowers 2, 202 are to be returned to the charging station 110 depending on whether the (second) determination voltage value is less than or equal to the corrected return threshold value Vre'.

[0108] According to the configuration described above, the control unit 8 determines whether or not to return the robotic lawnmowers 2, 202 to the charging station 110 based not only on the first-stage voltage value V1 and the second-stage voltage value V2, but also on the predetermined return threshold value Vre. Thus, the timing for returning the robotic lawnmowers 2, 202 to the charging station 110 can be determined more accurately.

[0109] In one or more embodiments, the control unit 8 is configured to receive a value detected by the battery voltage detection circuit 42 as a (third) determination voltage value. The control unit 8 is configured to execute the two-stage detection process when the (third) determination voltage value is less than or equal to the feedback threshold Vre. The control unit 8 is configured not to execute the two-stage detection process when the (third) determination voltage value is above the feedback threshold Vre.

[0110] When a value detected by the battery voltage detection circuit 42 is high to a certain degree, it is obvious that there is no need to return the robotic lawnmowers 2, 202 without executing the two-stage detection process. If the two-stage detection process is executed when the voltage value of the battery 18 is high to a certain degree, the working motor 36 is temporarily stopped unnecessarily, thereby hindering the smooth progress of the work by the robotic lawnmowers 2, 202. According to the above-described configuration, the control unit 8 is configured not to execute the two-stage detection process when the voltage value of the battery 18 is high to a certain degree. Therefore, the above-described configuration can prevent the working motor 36 from being stopped unnecessarily, thus allowing the work by the robotic lawnmowers 2, 202 to continue smoothly.

[0111] In one or more embodiments, in the threshold correction process, the control unit 8 corrects the feedback threshold Vre based on the recovery voltage value Vdiff obtained by subtracting the first-stage voltage value V1 from the second-stage voltage value V2.

[0112] The configuration described above allows the feedback threshold Vre to be corrected using a simple configuration.

[0113] In one or more embodiments, in the threshold correction process, the control unit 8 corrects the feedback threshold Vre by subtracting the recovery voltage value Vdiff from the feedback threshold Vre.

[0114] The working motor 36 can be configured to operate while the robotic lawnmowers 2, 202 are operating and to stop while the robotic lawnmowers 2, 202 are on the return path to the charging station 110. In this case, when the robotic lawnmowers 2, 202 start returning after work, the voltage value of the battery 18 is expected to recover by an amount equal to the recovery voltage value Vdiff. Therefore, when determining whether or not to return the robotic lawnmowers 2, 202, it is desirable to consider the recovery (recovery) of the voltage value of the battery 18 by the recovery voltage value Vdiff. The configuration described above considers the recovery (recovery) of the battery voltage value by the recovery voltage value Vdiff when determining whether or not to return the robotic lawnmowers 2, 202.Thus, the time for returning the robotic lawnmowers 2, 202 to the charging station 110 can be determined more accurately.

[0115] In one or more embodiments, in the threshold correction process, when the recovery voltage value Vdiff is greater than or equal to the predetermined upper limit value (e.g., 0.5 V), the control unit 8 subtracts the upper limit value from the feedback threshold value Vre instead of subtracting the recovery voltage value Vdiff from the feedback threshold value Vre.

[0116] If the recovery voltage value Vdiff calculated in the threshold correction process is large, a recovery amount (recovery amount) of the battery voltage value at the time when the robotic lawnmowers 2, 202 start returning after work may be smaller than the calculated recovery voltage value Vdiff. In this case, if the correction is performed by subtracting the large recovery voltage value Vdiff from the return threshold value Vre, the battery voltage value at the time when the robotic lawnmowers 2, 202 start returning will be smaller than expected. Therefore, the battery 18 may become depleted while the robotic lawnmowers 2, 202 are on the return path (return path).According to the configuration described above, when the recovery voltage value Vdiff calculated in the threshold correction process is greater than or equal to the upper limit value, a value obtained by subtracting the upper limit value from the return threshold value Vre is used as the corrected return threshold value Vre', instead of a value obtained by subtracting the recovery voltage value Vdiff from the return threshold value Vre. This prevents the battery voltage value at the time when the robotic lawnmowers 2, 202 start returning from being lower than expected. This configuration can prevent the battery 18 from becoming depleted while the robotic lawnmowers 2, 202 are on the return path.

[0117] In one or more embodiments, in the threshold correction process, when the recovery voltage value Vdiff is less than or equal to the predetermined lower limit value (e.g., 0.1 V), the control unit 8 determines the feedback threshold value Vre before the correction as the corrected feedback threshold value Vre'.

[0118] If the two-stage sensing process and the threshold correction process are performed when the battery voltage value has decreased to approximately the return threshold Vre, the resulting recovery voltage value Vdiff may be small. In this case, even if the working motor 36, which was stopped during the two-stage sensing process, is restarted for the robotic lawnmowers 2, 202 to resume work, the robotic lawnmowers 2, 202 must start returning shortly thereafter. That is, actions performed by the robotic lawnmowers 2, 202 from restarting work to starting return do not greatly affect the work progress and thus may be unnecessary. The work efficiency of the robotic lawnmowers 2, 202 may decrease if the robotic lawnmowers 2, 202 perform unnecessary actions for a long time.According to the configuration described above, when the recovery voltage value Vdiff calculated in the threshold correction process is small, the corrected return threshold Vre' is equal to the return threshold Vre before correction. That is, the corrected return threshold Vre' is greater than a value obtained by subtracting the recovery voltage value Vdiff from the return threshold Vre. Therefore, the robotic lawnmowers 2, 202 start returning sooner, and thus the robotic lawnmowers 2, 202 perform unnecessary actions only for a short time. This improves the working efficiency of the robotic lawnmowers 2, 202.

[0119] In one or more embodiments, the control unit 8 is configured to perform the two-stage sensing process while the motion motors 32L, 32R (examples of a non-target motor) are not operating.

[0120] The two-stage sensing process is a process for observing changes in the battery voltage value caused by changes in the operating state of the working motor 36. However, the battery voltage may also change due to the operating state of the moving motors 32L, 32R. Therefore, if the operating state of the moving motors 32L, 32R changes during the two-stage sensing process, changes in the battery voltage value caused by changes in the operating state of the working motor 36 cannot be accurately observed. With the configuration described above, the operating state of the moving motors 32L, 32R does not change during the two-stage sensing process, and thus changes in the battery voltage value caused by changes in the operating state of the working motor 36 can be accurately observed.

[0121] In one or more embodiments, the control unit 8 is configured to perform the feedback determination process while the movement motors 32L, 32R are not operating.

[0122] If the operating state of the movement motors 32L, 32R in the two-stage detection process is different from that in the return determination process, the timing for returning the robotic lawnmowers 2, 202 to the charging station 110 cannot be accurately determined. With the configuration described above, the operating state of the movement motors 32L, 32R is the same as in the two-stage detection process and the return determination process, and thus the timing for returning the robotic lawnmowers 2, 202 to the charging station 110 can be accurately determined.

[0123] In one or more embodiments, the control unit 8 is configured to stop the movement motors 32L, 32R at or after the time when the operating time of the movement motors 32L, 32R reaches a predetermined duration (e.g., two seconds).

[0124] It is desirable that the two-stage detection process (or the return determination process) be repeated at appropriate time intervals until the time to return the robotic lawnmowers 2, 202 is determined. However, in the configuration in which the two-stage detection process (or the return determination process) is executed while the movement motors 32L, 32R are not operating, the two-stage detection process (or the return determination process) cannot be executed while the movement motors 32L, 32R are operating. According to the above-described configuration, the movement motors 32L, 32R are forcibly (mandatorily) stopped at or after the time when the operation time of the movement motors 32L, 32R reaches the predetermined time. Therefore, the two-stage detection process (or determination detection process) can be repeated at appropriate time intervals.

[0125] In one or more embodiments, the working motor 36 is the target motor. The movement motors 32L, 32R are the non-target motors.

[0126] It is expected that the working motor 36 will be operating (in operation) while the robotic lawnmowers 2, 202 are operating, and that it will not be operating while the robotic lawnmowers 2, 202 are on the return path to the charging station 110. Therefore, it is essential to obtain battery voltage values ​​for the respective operating states of the working motor 36 in order to determine the time to return the robotic lawnmowers 2, 202. Conversely, it is expected that the movement motors 32L, 32R will generally continue to run (operate) while the robotic lawnmowers 2, 202 are operating and also while the robotic lawnmowers 2, 202 are on the return path to the charging station 110. Therefore, it is less necessary to obtain battery voltage values ​​for the respective operating states of the movement motors 32L, 32R in order to determine the time to return the robotic lawnmowers 2, 202.However, if battery voltage values ​​are obtained for the respective operating states of the movement motors 32L, 32R, the processing load on the control unit 8 is unnecessarily increased. According to the configuration described above, battery voltage values ​​are obtained for the respective operating states of the working motor 36, but battery voltage values ​​are not obtained for the respective operating states of the movement motors 32L, 32R. Therefore, the configuration described above can reduce the processing load on the control unit 8 and also accurately determine the time to return the robotic lawnmowers 2, 202 to the charging station 110.

[0127] In one or more embodiments, the working mechanism includes the blade 34 configured to mow the lawn. The working robot functions as the autonomously movable robotic mower 2, 202.

[0128] The configuration described above makes it possible to return the robotic lawnmowers 2, 202 to the charging station 110 at the appropriate time. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2016-10 382 A

[0002]

Claims

[1] Work robot (2) configured to move and work autonomously, with a working mechanism (34) configured to work, a movement mechanism (30L, 30R) configured to move the working robot (2), a working motor (36) configured to drive the working mechanism (34), a movement motor (32L, 32R) configured to drive the movement mechanism (30L, 30R), a battery (18) which is rechargeable and is configured to supply power to the working motor (36) and the movement motor (32L, 32R), a voltage detection unit (42) configured to detect a voltage value of the battery (18), and a control unit (8), in which the control unit (8) is configured to a two-stage detection process (S12, S14, S16) in which the control unit (8) obtains a detection value detected by the voltage detection unit (42) while a target motor (36) is in operation as a first-stage voltage value (V1), and then the control unit (8) stops the target motor (36) and obtains a detection value detected by the voltage detection unit (42) while the target motor (36) is not in operation as a second-stage voltage value (V2), in which the target motor (36) is at least one of the working motor (36) and the moving motor (32L, 32R), and to execute a return determination process (S36) in which the control unit (8) determines whether or not the work robot (2) is to be returned to a charging station (110) based on the first-stage voltage value (V1) and the second-stage voltage value (V2). [2] Working robot (2) according to claim 1, in which the control unit (8) is configured to receive a detection value detected by the voltage detection unit (42) as a first determination voltage value, the control unit (8) is configured to execute the two-stage detection process (S12, S14, S16) when the first determination voltage value is less than or equal to a predetermined value (Vre, Vth), and the control unit (8) is configured not to execute the two-stage detection process (S12, S14, S16) when the first determination voltage value is above the predetermined value (Vre, Vth). [3] Working robot (2) according to claim 1, in which the control unit (8) stores a predetermined feedback threshold value (Vre), the control unit (8) is configured to further execute a threshold correction process (S18, S20, S22, S24, S26, S28) in which the control unit (8) corrects the feedback threshold (Vre) based on the first-stage voltage value (V1) and the second-stage voltage value (V2), and the return determination process (S36) includes a process in which the control unit (8) obtains a detection value detected by the voltage detection device (42) as a second determination voltage value, and determines whether or not the work robot (2) is to be returned to the charging station (110) depending on whether the second determination voltage value is less than or equal to a corrected return threshold value (Vre'). [4] Working robot (2) according to claim 3, in which the control unit (8) is configured to receive a detection value detected by the voltage detection unit (42) as a third determination voltage value, the control unit (8) is configured to execute the two-stage detection process (S12, S14, S16) when the third determination voltage value is less than or equal to the feedback threshold value (Vre), and the control unit (8) is configured not to execute the two-stage detection process (S12, S14, S16) if the third determination voltage value is above the feedback threshold (Vre). [5] The working robot (2) according to claim 3 or 4, wherein in the threshold correction process (S18, S20, S22, S24, S26, S28), the control unit (8) corrects the feedback threshold (Vre) based on a recovery voltage value (Vdiff) obtained by subtracting the first-stage voltage value (V1) from the second-stage voltage value (V2). [6] The working robot (2) according to claim 5, wherein in the threshold correction process (S18, S20, S22, S24, S26, S28), the control unit (8) corrects the feedback threshold (Vre) by subtracting the recovery voltage value (Vdiff) from the feedback threshold (Vre). [7] The working robot (2) according to claim 6, wherein, in the threshold correction process (S18, S20, S22, S24, S26, S28), when the recovery voltage value (Vdiff) is greater than or equal to a predetermined upper limit value, the control unit (8) subtracts the upper limit value from the feedback threshold value (Vre) instead of subtracting the recovery voltage value (Vdiff) from the feedback threshold value (Vre). [8] A working robot (2) according to any one of claims 5 to 7, wherein in the threshold correction process (S18, S20, S22, S24, S26, S28), when the recovery voltage value (Vdiff) is less than or equal to a predetermined lower limit value, the control unit (8) determines the feedback threshold value (Vre) before correction as the corrected feedback threshold value (Vre'). [9] Working robot (2) according to one of claims 1 to 8, in which one of the working motor (36) and the movement motor (32L, 32R) is the target motor (36), the other of the working motor (36) and the moving motor (32L, 32R) is a non-target motor (32L, 32R) which is not the target motor (36), and the control unit (8) is configured to execute the two-stage detection process (S12, S14, S16) while the non-target motor (32L, 32R) is not in operation. [10] The work robot (2) according to claim 9, wherein the control unit (8) is configured to execute the feedback determination process (S36) while the non-target motor (32L, 32R) is not operating. [11] The working robot (2) according to claim 9 or 10, wherein the control unit (8) is configured to stop the non-target motor (32L, 32R) at or after a time when an operation time of the non-target motor (32L, 32R) reaches a predetermined time. [12] A working robot (2) according to any one of claims 9 to 11, wherein the working motor (36) is the target motor (36), and the moving motor (32L, 32R) is the non-target motor (32L, 32R). [13] Working robot (2) according to one of claims 1 to 12, in which the working mechanism (34) has a blade (34) configured to mow a lawn, and the working robot (2) functions as an autonomously movable mowing robot.

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