Work robot

Abstract

To provide a technique capable of smoothly advancing work by a work robot.SOLUTION: A work robot executes work while autonomously moving. The work robot includes: a robot main body that includes a base and a bumper supported by the base; a work unit that is supported by the base; a moving mechanism that moves the base; a movement motor that drives the moving mechanism; a first detecting unit that detects force received by the bumper or the displacement of the bumper relative to the base; a second detecting unit that detects an angular speed of the base or a state of the movement motor; and a control unit. The control unit is configured to be able to determine whether or not the movement of the work robot is interrupted by an obstacle based on a detection result of the first detecting unit and a detection result of the second detecting unit.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a working robot. [Background technology]

[0002] Patent Document 1 discloses a work robot that performs work while moving autonomously. The work robot includes a robot body including a base and a bumper supported by the base, a working unit supported by the base, a movement mechanism that moves the base, a movement motor that drives the movement mechanism, a first detection unit that detects the force received by the bumper or the displacement of the bumper relative to the base, and a control unit. The control unit is configured to be able to determine whether or not the movement of the work robot is being hindered by the obstacle based on the detection result of the first detection unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-325812 Summary of the Invention [Problem to be solved by the invention]

[0004] The control unit of the work robot may cause the work robot to perform an avoidance operation to move around the obstacle in response to determining that the movement of the work robot is hindered by an obstacle. In this case, if the accuracy of determining whether the movement of the work robot is hindered by an obstacle is poor, it may be difficult for the work robot to avoid the obstacle. For example, it may take time for the work robot to avoid the obstacle. As a result, the work by the work robot may not proceed smoothly. This specification provides a technology that allows the work by the work robot to proceed smoothly. [Means for solving the problem]

[0005] The working robot disclosed in this specification performs work while moving autonomously. The working robot includes a robot body including a base and a bumper supported by the base, a working unit supported by the base, a movement mechanism for moving the base, a movement motor for driving the movement mechanism, a first detection unit for detecting a force applied to the bumper or a displacement of the bumper relative to the base, a second detection unit for detecting an angular velocity of the base or a state of the movement motor, and a control unit. The control unit is configured to be able to determine whether or not movement of the working robot is being hindered by the obstacle based on the detection results of the first detection unit and the second detection unit.

[0006] With the above configuration, the control unit of the work robot can determine whether or not the movement of the work robot is being hindered by an obstacle based not only on the force received by the bumper or the displacement of the bumper relative to the base, but also on the angular velocity of the base or the state of the movement motor. This improves the accuracy of determining whether or not the movement of the work robot is being hindered by an obstacle, allowing the work robot to easily avoid the obstacle. Therefore, the above configuration allows the work by the work robot to proceed smoothly. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of use of the robot lawnmower 2 according to the first embodiment. FIG. [Diagram 2] FIG. 2 is a left side view of the robotic lawnmower 2 according to the first embodiment. [Diagram 3] FIG. 2 is a rear view of the robotic lawnmower 2 according to the first embodiment. [Figure 4] 1 is a schematic configuration diagram of a robotic lawnmower 2 according to a first embodiment. [Diagram 5] 2 is a diagram showing a schematic configuration of the vicinity of a collision detection sensor 66 of the robot lawnmower 2 according to the first embodiment. FIG. [Figure 6] 2 is a diagram showing a schematic configuration of the vicinity of a lifting detection sensor 68 of the robotic lawnmower 2 according to the first embodiment. FIG. [Figure 7]10 is a flowchart of autonomous driving executed by a control unit 8 of the robotic lawnmower 2 according to the first embodiment when an automatic height adjustment function is on. [Figure 8] 3 is a diagram showing a schematic diagram of a threshold value table TT stored in a memory 36 of a control unit 8 of the robotic lawnmower 2 according to the first embodiment. FIG. [Figure 9] 10 is a flowchart of autonomous driving executed by the control unit 8 of the robotic lawnmower 2 according to the first embodiment when the automatic height adjustment function is turned off. [Figure 10] 4 is a flowchart of a process executed by a control unit 8 while the robotic lawnmower 2 according to the first embodiment is operating autonomously. [Figure 11] 10 is a flowchart of a process executed by a control unit 8 while a robotic lawnmower 202 according to a second embodiment is operating autonomously. [Figure 12] 10 is a flowchart of a process executed by a control unit 8 while a robotic lawnmower 302 according to a third embodiment is operating autonomously. [Figure 13] 13 is a flowchart of autonomous driving executed by a control unit 8 of a robotic lawnmower 402 according to Example 4 when an automatic height adjustment function is on. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Representative and non-limiting examples of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing the preferred examples of the present invention, and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide further improved work robots.

[0009] In addition, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, but are specifically described only to illustrate representative embodiments of the present invention. Furthermore, the various features of the following representative embodiments and the various features described in the claims do not have to be combined in the exact manner of the embodiments described herein or in the order listed in order to provide additional and useful embodiments of the present invention.

[0010] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, the control unit may be configured to execute a first obstruction judgment process that determines whether or not movement of the work robot is obstructed by the obstacle based on at least a detection result of the first detection unit; an avoidance process that operates the movement motor so that the work robot performs an avoidance operation to move around the obstacle after it is determined in the first obstruction judgment process that movement of the work robot is obstructed by the obstacle; and a second obstruction judgment process that determines whether or not movement of the work robot is obstructed by the obstacle based on at least a detection result of the second detection unit while the work robot is performing the avoidance operation.

[0012] In the above configuration, when the work robot (specifically, the bumper) interferes with an obstacle, the control unit determines that the movement of the work robot is hindered by the obstacle and causes the work robot to perform an avoidance operation. However, as the work robot performs an avoidance operation, a part of the work robot other than the bumper may interfere with the obstacle, causing the movement of the work robot to be hindered by the obstacle. In this case, the detection result of the first detection unit (the force received by the bumper or the displacement of the bumper relative to the base) does not show any particular sign that the movement of the work robot is hindered by an obstacle. Therefore, if the control unit determines whether the movement of the work robot is hindered by an obstacle based only on the first detection unit while the work robot is performing an avoidance operation, there is a risk that the determination result will be erroneous. In contrast, according to the above configuration, while the work robot is performing an avoidance operation, the control unit determines whether the movement of the work robot is hindered by an obstacle based on at least the second detection unit. This makes it possible to suppress an erroneous determination result regarding whether the movement of the work robot is hindered by an obstacle. Therefore, with the above configuration, it is possible to accurately determine whether or not the movement of the work robot is being hindered by an obstacle.

[0013] In one or more embodiments, the avoidance movement may include a turning movement in which the work robot turns.

[0014] According to the above configuration, the avoidance operation can be made relatively complicated.

[0015] In one or more embodiments, the avoidance movement may include a straight movement movement in which the work robot moves in a straight line.

[0016] If the avoidance operation were to consist only of a turning motion, there is a possibility that the work robot would not move away from the obstacle after coming into contact with it. In this case, it would take time for the work robot to avoid the obstacle, and there is a risk that the work performed by the work robot would not proceed smoothly. With the above configuration, the avoidance operation includes a straight movement motion, so that the work robot is more likely to move away from the obstacle after coming into contact with it. This reduces the time required for the work robot to avoid the obstacle, allowing the work performed by the work robot to proceed smoothly.

[0017] In one or more embodiments, the state of the movement motor may include a current flowing through the movement motor. The second detection unit may include a motor current detection unit that detects a current flowing through the movement motor.

[0018] If the movement motor is operated while the movement of the work robot is hindered by an obstacle, the obstacle acts as resistance and a larger load than usual is applied to the movement motor. In this case, it is expected that the current flowing through the movement motor will be larger than usual. With the above configuration, while the movement motor is being operated, the control unit can estimate the load on the movement motor from the current flowing through the movement motor and determine whether the movement of the work robot is being hindered by an obstacle.

[0019] In one or more embodiments, the control unit may determine that movement of the work robot is being obstructed by the obstacle when a situation in which the detection value of the motor current detection unit is equal to or greater than a predetermined current value continues for a predetermined period of time or longer.

[0020] The control unit may cause the work robot to perform an avoidance operation to move around the obstacle in response to determining that the movement of the work robot is hindered by an obstacle. In this configuration, if it is determined that the movement of the work robot is hindered by an obstacle at the timing when the detection value of the motor current detection unit becomes equal to or greater than a predetermined current value, the avoidance operation may be performed unnecessarily. This is because the obstacle may be avoided by normal operation of the work robot without performing the avoidance operation. According to the above configuration, it is determined that the movement of the work robot is hindered by an obstacle when the situation in which the detection value of the motor current detection unit becomes equal to or greater than the predetermined current value continues for a predetermined time or more. Therefore, the avoidance operation is performed only when the state in which the movement of the work robot is hindered by the obstacle continues to a certain extent. This makes it possible to suppress the unnecessary performance of the avoidance operation. As a result, the work by the work robot can proceed smoothly.

[0021] In one or more embodiments, the working unit may include a blade for cutting grass. The working robot may function as a robotic lawnmower.

[0022] According to the above configuration, work by the robotic lawnmower can proceed smoothly.

[0023] (Example 1: Robotic lawnmower 2) As shown in FIG. 1, the working robot of this embodiment is, for example, a robotic lawnmower 2 used within a site 100 where a lawn is laid. The site 100 is provided with, for example, a house 102, a pond 104, and a road 106. Also provided within the site 100 are a charging station 110 connected to an external power source (for example, a commercial power source) and a wire 112 that defines a working area WA of the robotic lawnmower 2. The "working area WA" here is the area surrounded by the wire 112. The robotic lawnmower 2 can detect the position of the wire 112 and move autonomously so as not to deviate from the working area WA in which the robotic lawnmower 2 is located. This allows the robotic lawnmower 2 to perform lawnmowing work while moving over the lawn so as to avoid the house 102, the pond 104, and the road 106.

[0024] 2, 3, and 4, the robotic lawnmower 2 includes a robot body 4, a power supply unit 6, a control unit 8, an input operation unit 10, a communication unit 12, a display unit 14, an alarm unit 16, a moving unit 18, a working unit 20, a height adjustment unit 22, and a detection unit 24. The power supply unit 6, the control unit 8, the input operation unit 10, the communication unit 12, the display unit 14, the alarm unit 16, the moving unit 18, the working unit 20, the height adjustment unit 22, and the detection unit 24 are each supported by the robot body 4.

[0025] As shown in Fig. 2, the robot main body 4 includes a base frame 26 and a body 28 supported by the base frame 26. The body 28 is provided so as to cover the base frame 26 from above. The body 28 is supported so as to be movable in all directions relative to the base frame 26. Normally, the body 28 is held in the position shown in Fig. 2 by a spring or the like.

[0026] The power supply unit 6 shown in FIG. 4 is capable of supplying power to each unit of the robotic lawnmower 2 via a power supply circuit 38 of the control unit 8. The power supply unit 6 includes a rechargeable battery 30, such as a lithium-ion battery, and a charging interface 32 that electrically connects to the battery 30. The nominal capacity of the battery 30 is, for example, 5.0 Ah. The nominal voltage of the battery 30 is, for example, 18 V. The robotic lawnmower 2 can be docked to a charging station 110 (see FIG. 1) via the charging interface 32. When the robotic lawnmower 2 is docked to the charging station 110, the battery 30 can be charged by power supplied from the charging station 110. The charging method for the battery 30 may be wired charging. Specifically, the battery 30 may be charged in a state in which a terminal provided on the charging station 110 and a terminal provided on the charging interface 32 are connected to each other. Alternatively, the charging method for the battery 30 may be wireless charging. Specifically, the battery 30 may be charged by causing a power transmitting coil provided in the charging station 110 to generate an induced electromotive force in a power receiving coil provided in the charging interface 32.

[0027] The control unit 8 includes a processor 34, a memory 36, and a power supply circuit 38. The memory 36 includes a ROM, a RAM, and the like. The ROM stores a program for autonomously controlling the robotic lawnmower 2. The RAM temporarily stores various signals input to the control unit 8 and various data (e.g., flags) generated in the process of the processor 34 executing processing. The processor 34 is configured to control the robotic lawnmower 2 by executing processing based on the information stored in the memory 36. The memory 36 also stores settings related to the robotic lawnmower 2. The settings related to the robotic lawnmower 2 include, for example, settings related to the working time zone of the robotic lawnmower 2. The "working time zone" here refers to a time zone during which the robotic lawnmower 2 can perform work. By setting the working time zone, it is possible to prevent work from being performed during a time zone not intended by the user (e.g., at night). The settings related to the robotic lawnmower 2 also include settings related to the height adjustment of the cutting blade 46. The settings related to the height adjustment of the cutting blade 46 include an on / off setting of an automatic height adjustment function for automatically adjusting the height h (see FIG. 2) of the cutting blade 46 during autonomous driving, which will be described later. The settings related to the height adjustment of the cutting blade 46 further include settings of the initial height of the cutting blade 46, the target height of the cutting blade 46, and the area of ​​the working area WA (see FIG. 1), which are required when the automatic height adjustment function is turned on, as well as a setting of a fixed height of the cutting blade 46, which is required when the automatic height adjustment function is turned off.

[0028] The input operation unit 10 is provided on the outer surface of the body 28 (see FIG. 2), and includes switches and the like that can be operated by the user. The user can perform various input operations related to the robotic lawnmower 2 via the input operation unit 10. The "input operations" referred to here include, for example, operations for switching the main power supply of the robotic lawnmower 2 on / off, operations for issuing instructions to the robotic lawnmower 2, and operations for changing settings related to the robotic lawnmower 2.

[0029] The communication unit 12 is an interface for connecting to the Internet, for example, via a base station (not shown) for mobile communications (3G, 4G, 5G, etc.) or a router (not shown) installed in the house 102. The control unit 8 can perform wireless communication with a communication terminal (e.g., a smartphone) owned by the user via the communication unit 12. This allows the control unit 8 to notify the communication terminal owned by the user that an abnormality has occurred in the robotic lawnmower 2, for example. The user can also perform various input operations related to the robotic lawnmower 2 via the communication terminal, in the same way as with the input operation unit 10.

[0030] The display unit 14 is provided on the outer surface of the body 28 (see FIG. 2). The display unit 14 includes, for example, a display (not shown) that displays characters and images, and a light source device that displays the status of the robotic lawnmower 2 by the chromaticity and blinking pattern of light. The "status of the robotic lawnmower 2" here includes, for example, a state in which the battery 30 is charging, or a state in which an abnormality has occurred in the robotic lawnmower 2.

[0031] The warning sound unit 16 includes, for example, a buzzer (not shown). The warning sound unit 16 can notify the user that an abnormality has occurred in the robotic lawnmower 2 by emitting a sound.

[0032] The moving unit 18 includes a pair of casters 40L, 40R, a pair of drive wheels 42L, 42R, and a pair of moving motors 44L, 44R. The moving motors 44L, 44R are, for example, brushless DC motors. The drive wheels 42L, 42R are connected to the output shafts (not shown) of the moving motors 44L, 44R, respectively. As shown in FIG. 2 and FIG. 3, the robotic lawnmower 2 is placed on the ground G with the casters 40L, 40R and the drive wheels 42L, 42R in contact with the ground G. The moving unit 18 can move the robotic lawnmower 2 forward, backward, and turn by operating the moving motors 44L, 44R (see FIG. 4) to rotate the drive wheels 42L, 42R. In this embodiment, the direction perpendicular to the ground G, that is, the direction from the ground G toward the robot body 4 is the upward direction, and the direction from the robot body 4 toward the ground G is the downward direction. The direction perpendicular to the up-down direction, from drive wheel 42R to drive wheel 42L, is defined as the left direction, and the direction from drive wheel 42L to drive wheel 42R is defined as the right direction. The direction perpendicular to the up-down direction and the left-right direction, from drive wheels 42L, 42R to casters 40L, 40R is defined as the front direction, and the direction from casters 40L, 40R to drive wheels 42L, 42R is defined as the rear direction.

[0033] As shown in FIG. 2, the working unit 20 includes a cutting blade 46 and a work motor 48. The cutting blade 46 is a rotary blade formed in a substantially circular disk shape. The work motor 48 is, for example, a brushless DC motor. The work motor 48 is disposed in a state in which an output shaft 50 is inclined from front to rear as it goes from top to bottom. The cutting blade 46 is connected to the output shaft 50 of the work motor 48. The working unit 20 can cut the grass by operating the work motor 48 to rotate the cutting blade 46.

[0034] The height adjustment unit 22 includes a height adjustment mechanism 52 and a height adjustment motor 54. The height adjustment mechanism 52 includes an outer cylinder 58 having a female thread 56 and an inner cylinder 62 having a male thread 60. The male thread 60 of the inner cylinder 62 is screwed into the female thread 56 of the outer cylinder 58. The outer cylinder 58 is supported so as to be immovable in the vertical direction relative to the base frame 26 and rotatable about an axis along the vertical direction relative to the base frame 26. The inner cylinder 62 is supported so as to be movable in the vertical direction relative to the base frame 26 and to be imrotatable relative to the base frame 26. The working unit 20 is fixed to the inner cylinder 62. The height adjustment motor 54 is, for example, a brushless DC motor. An output shaft (not shown) of the height adjustment motor 54 is connected to the outer cylinder 58 via a gear or the like. The height adjustment unit 22 can change the vertical position of the inner cylinder 62 by operating the height adjustment motor 54 to rotate the outer cylinder 58. This allows the height adjustment unit 22 to change the height h of the cutting blade 46. In this embodiment, the height h of the cutting blade 46 is represented by the distance between the lower end of the cutting blade 46 and the ground G. The height h of the cutting blade 46 is within a range of 10 mm to 80 mm, for example, and can be changed within a range of 20 mm to 60 mm in this embodiment.

[0035] As shown in FIG. 4, the detection unit 24 includes a wire detection sensor 64, a collision detection sensor 66, a lifting detection sensor 68, an angular velocity detection sensor 70, a motor current detection circuit 72, and a battery voltage detection circuit 74.

[0036] The wire detection sensor 64 is a sensor for detecting the wire 112 (see FIG. 1). The wire detection sensor 64 is, for example, a Hall sensor. In this embodiment, a predetermined electric signal is applied to the wire 112 from the charging station 110 (see FIG. 1). As a result, a magnetic signal corresponding to the predetermined electric signal is generated around the wire 112. The wire detection sensor 64 is configured to detect this magnetic signal and output it to the control unit 8. Based on the signal pattern and signal strength of the magnetic signal detected by the wire detection sensor 64, the control unit 8 can determine whether the robotic lawnmower 2 is approaching the wire 112, whether the robotic lawnmower 2 is located above the wire 112, etc.

[0037] The collision detection sensor 66 is a sensor for detecting when the robot lawnmower 2 collides with an obstacle. The collision detection sensor 66 is, for example, a Hall sensor. As shown in FIG. 5, the collision detection sensor 66 is provided on the base frame 26. A magnet 76 is provided on the body 28 at a location facing the collision detection sensor 66 in the up-down direction. The collision detection sensor 66 detects the strength of the magnetic field generated by the magnet 76 provided on the body 28. If the strength of the detected magnetic field is large, the collision detection sensor 66 outputs an H signal to the control unit 8 (see FIG. 4), and if the strength of the detected magnetic field is small, the collision detection sensor 66 outputs an L signal to the control unit 8. When the body 28 is in the position shown in FIG. 2, the position of the collision detection sensor 66 in the horizontal direction and the position of the magnet 76 in the horizontal direction overlap each other. Therefore, the strength of the magnetic field detected by the collision detection sensor 66 is large, and the collision detection sensor 66 outputs an H signal to the control unit 8. 2, the position of the collision detection sensor 66 in the horizontal direction and the position of the magnet 76 in the horizontal direction are offset from each other. As a result, the strength of the magnetic field detected by the collision detection sensor 66 decreases, and an L signal is output from the collision detection sensor 66 to the control unit 8.

[0038] The lifting detection sensor 68 is a sensor for detecting that the robotic lawnmower 2 has been lifted from the ground G. The lifting detection sensor 68 is, for example, an inductive sensor. As shown in FIG. 6, the lifting detection sensor 68 is provided on the base frame 26. A metal plate 78 is provided on the body 28 at a location facing the lifting detection sensor 68 in the up-down direction. The lifting detection sensor 68 detects whether the metal plate 78 provided on the body 28 is nearby. If the metal plate 78 is nearby, the lifting detection sensor 68 outputs an H signal to the control unit 8 (see FIG. 4), and if the metal plate 78 is not nearby, the lifting detection sensor 68 outputs an L signal to the control unit 8. When the body 28 is in the position shown in FIG. 2, the metal plate 78 is near the lifting detection sensor 68, so that the lifting detection sensor 68 outputs an H signal to the control unit 8. When the body 28 moves upward from the position shown in FIG. 2, the metal plate 78 moves away from the lifting detection sensor 68, so that the lifting detection sensor 68 outputs an L signal to the control unit 8.

[0039] 4 is provided on the base frame 26 (see FIG. 2). The angular velocity detection sensor 70 detects the angular velocity of the base frame 26, and outputs the detected angular velocity to the control unit 8.

[0040] The battery voltage detection circuit 74 detects the voltage value of the battery 30 (that is, the remaining charge of the battery 30), and outputs the detected voltage value to the control unit 8.

[0041] The motor current detection circuit 72 detects the value of the current supplied to each of the moving motors 44L, 44R and the working motor 48, and outputs the detected current values ​​to the control unit 8.

[0042] (Autonomous Driving) The following describes the autonomous driving executed by the control unit 8 (specifically, the processor 34). The autonomous driving in this embodiment differs in operation content depending on whether the automatic height adjustment function is on or off.

[0043] (Autonomous operation when automatic height adjustment function is on) When the automatic height adjustment function is on, the robotic lawnmower 2 changes the height h of the cutting blade 46 (see FIG. 2) in stages from the initial height to the target height. In this embodiment, the initial height is set to a value greater than the target height. For example, the initial height is set to 50 mm, and the target height is set to 30 mm. Therefore, the robotic lawnmower 2 lowers the height h of the cutting blade 46 in stages from the initial height to the target height. Below, referring to FIG. 7, the autonomous operation when the automatic height adjustment function is on will be described in detail.

[0044] The process shown in FIG. 7 is started when an instruction to start autonomous driving is given via the input operation unit 10 (see FIG. 4) or a user's communication terminal while the automatic height adjustment function is on.

[0045] In S2, the control unit 8 operates the height adjustment motor 54 (see FIG. 2) to adjust the height h of the cutting blade 46 to an initial height previously set by the user. After S2, the process proceeds to S4.

[0046] In S4, the control unit 8 determines whether or not the current time is within a work time zone. If the current time is not within a work time zone (NO), the process proceeds to S6.

[0047] In S6, the control unit 8 causes the robotic lawnmower 2 to wait at the charging station 110 (see FIG. 1). If the robotic lawnmower 2 is not at the charging station 110 when S6 begins, the control unit 8 causes the robotic lawnmower 2 to return to the charging station 110. Specifically, with the work motor 48 (see FIG. 4) stopped, the control unit 8 operates the movement motors 44L, 44R (see FIG. 4) so ​​that the robotic lawnmower 2 follows the wire 112 to the charging station 110. After that, with the work motor 48 and the movement motors 44L, 44R stopped, the control unit 8 causes the robotic lawnmower 2 to wait at the charging station 110. After S6, the process returns to S4.

[0048] If the current time is within the work time zone in S4 (YES), the process proceeds to S8. In S8, the control unit 8 starts mowing work with the robotic lawnmower 2. Specifically, the control unit 8 operates the movement motors 44L, 44R to move the robot body 4, while operating the work motor 48 to mow the grass with the cutting blade 46. This causes the height of the grass to be aligned to the height h of the cutting blade 46. After S8, the process proceeds to S10.

[0049] In S10, the control unit 8 judges whether a predetermined grass height uniformity condition is satisfied. The grass height uniformity condition is, for example, a condition under which the height of the grass in the working area WA (see FIG. 1) is estimated to be uniform across the board at the height h of the cutting blade 46. The grass height uniformity condition includes a first grass height uniformity condition in which the cumulative value of the mowing operation time in a state where the height h of the cutting blade 46 does not change exceeds a first operation time threshold. The "mowing operation time" here means the time elapsed from the start to the end of the mowing operation, excluding the time elapsed while the mowing operation is interrupted. The mowing operation time is, for example, the time during which the working motor 48 is operated while the mowing operation is being performed. The "cumulative value of the mowing operation time" is the sum of the mowing operation times for each mowing operation when the mowing operation is performed multiple times in a state where the height h of the cutting blade 46 does not change. The "first operation time threshold" is a time threshold determined based on the area of ​​the working area WA. A threshold table TT as shown in FIG. 8 is stored in the memory 36 of the control unit 8. The threshold table TT describes the first work time threshold to be determined in association with the area of ​​the work area WA. Therefore, the control unit 8 can determine the first work time threshold corresponding to the area of ​​the work area WA previously set by the user. In the threshold table TT, one first work time threshold is assigned to each of a plurality of area ranges. The grass height uniformity condition further includes a second grass height uniformity condition that the cumulative value of the grass mowing work time in a state where the battery 30 (see FIG. 4) is not charged exceeds a predetermined second work time threshold. The second work time threshold is, for example, 2.0 hours or more, and is 2.5 hours in this embodiment. Normally, when the height of the grass is aligned to the height h of the cutting blade 46, the load on the working motor 48 that drives the cutting blade 46 is reduced, so that the remaining charge of the battery 30 lasts longer. If the remaining charge of the battery 30 lasts longer, the cumulative value of the grass mowing work time in a state where the battery 30 is not charged also becomes longer accordingly. For this reason, if the cumulative time spent mowing without charging the battery 30 is long, it can be assumed that the height of the grass within the work area WA has become uniform across the board at the height h of the cutting blade 46. If any one of the above conditions is met, the control unit 8 determines that the uniform grass height condition is met (YES).If the uniform grass height condition is met (YES), the process proceeds to S12.

[0050] In S12, the control unit 8 turns on the uniform grass height flag, in other words, the control unit 8 stores in the memory 36 information indicating that the uniform grass height condition is met in S10.

[0051] If the grass height uniformity condition is not met in S10 (if NO), or after S12, the process proceeds to S14. In S14, the control unit 8 determines whether or not a predetermined feedback condition is met. The feedback condition includes a first feedback condition that the remaining charge of the battery 30 is low. Specifically, the first feedback condition is a condition that the voltage value of the battery 30 detected by the battery voltage detection circuit 74 (see FIG. 4) is equal to or lower than a predetermined voltage value (for example, 17.5 V). The feedback condition further includes a second feedback condition that the grass height uniformity flag is on. If any one of the above conditions is met, the control unit 8 determines that the feedback condition is met (YES). If the feedback condition is not met (if NO), the process returns to S10. If the feedback condition is met (if YES), the process proceeds to S16.

[0052] In S16, the control unit 8 ends the mowing operation started in S8 and returns the robotic lawnmower 2 to the charging station 110. Specifically, with the work motor 48 stopped, the control unit 8 operates the transport motors 44L, 44R so that the robotic lawnmower 2 follows the wire 112 to the charging station 110. After S16, the process proceeds to S18.

[0053] In S18, the control unit 8 docks the robotic lawnmower 2 to the charging station 110 and starts charging the battery 30. The control unit 8 then continues charging the battery 30 until a predetermined charging end condition is met. The charging end condition is, for example, that the voltage value of the battery 30 detected by the battery voltage detection circuit 74 is equal to or higher than a predetermined value (e.g., 20 V). When charging of the battery 30 ends in S18, the process proceeds to S20.

[0054] In S20, the control unit 8 determines whether the uniform grass height flag is on. If the uniform grass height flag is off (NO), the process returns to S4. If the uniform grass height flag is on (YES), the process proceeds to S22.

[0055] In S22, the control unit 8 determines whether the current height h of the blade 46 has reached the target height preset by the user. If the height h of the blade 46 has not reached the target height (i.e., the height h of the blade 46 is higher than the target height) (NO), the process proceeds to S24.

[0056] In S24, the control unit 8 operates the height adjustment motor 54 (see FIG. 2) to lower the height h of the cutting blade 46 by a predetermined amount (for example, 5 mm). Note that when S24 is executed, the robotic lawnmower 2 is at the charging station 110. This allows the height h of the cutting blade 46 to be lowered in a relatively safe location. In addition, the control unit 8 turns off the grass height uniformity flag in response to lowering the height h of the cutting blade 46. After S24, the process returns to S4.

[0057] If in S22 the height h of the cutting blade 46 has reached the target height (YES), the process proceeds to S26. In S26, the control unit 8 notifies the user that the height of the grass in the work area WA has been generally aligned to the target height. For example, the control unit 8 communicates with the user's communication terminal via the communication unit 12 (see FIG. 4) and causes the communication terminal to notify that the height of the grass in the work area WA has been generally aligned to the target height. After S26, the process shown in FIG. 7 ends.

[0058] The process shown in Fig. 7 also ends when an instruction to end autonomous driving is given via the input operation unit 10 or a user's communication terminal. The process shown in Fig. 7 also ends when the main power supply of the robotic lawnmower 2 is switched off via the input operation unit 10 or a user's communication terminal.

[0059] (Autonomous operation when automatic height adjustment function is turned off) When the automatic height adjustment function is turned off, the robotic lawnmower 2 continues to maintain the height h of the cutting blade 46 (see FIG. 2) at a fixed height preset by the user. Autonomous operation when the automatic height adjustment function is turned off will be described in detail below with reference to FIG.

[0060] The process shown in FIG. 9 is started when an instruction to start autonomous driving is given via the input operation unit 10 (see FIG. 4) or a user's communication terminal while the automatic height adjustment function is turned off.

[0061] In S32, the control unit 8 operates the height adjustment motor 54 (see FIG. 2) to adjust the height h of the cutting blade 46 to the fixed height. After S32, the process proceeds to S34.

[0062] In S34, the control unit 8 determines whether or not the current time is within the work time zone. If the current time is not within the work time zone (NO), the process proceeds to S36.

[0063] In S36, the control unit 8 causes the robotic lawnmower 2 to wait at the charging station 110 (see FIG. 1). If the robotic lawnmower 2 is not at the charging station 110 when S36 is started, the control unit 8 causes the robotic lawnmower 2 to return to the charging station 110. Specifically, with the working motor 48 (see FIG. 4) stopped, the control unit 8 operates the movement motors 44L, 44R (see FIG. 4) so ​​that the robotic lawnmower 2 follows the wire 112 to the charging station 110. After that, with the working motor 48 and the movement motors 44L, 44R stopped, the control unit 8 causes the robotic lawnmower 2 to wait at the charging station 110. After S36, the process returns to S34.

[0064] If the current time is within the work time zone in S34 (YES), the process proceeds to S38. In S38, the control unit 8 starts mowing work with the robotic lawnmower 2. Specifically, the control unit 8 operates the movement motors 44L, 44R to move the robot body 4, while operating the work motor 48 to mow the grass with the cutting blade 46. After S38, the process proceeds to S40.

[0065] In S40, the control unit 8 judges whether or not a predetermined feedback condition is satisfied. For example, this feedback condition is that the voltage value of the battery 30 detected by the battery voltage detection circuit 74 (see FIG. 4) is equal to or lower than a predetermined voltage value (for example, 17.5 V). If the feedback condition is not satisfied (NO), the process repeats S40. If the feedback condition is satisfied (YES), the process proceeds to S42.

[0066] In S42, the control unit 8 ends the mowing operation started in S38 and returns the robotic lawnmower 2 to the charging station 110. Specifically, with the work motor 48 stopped, the control unit 8 operates the transport motors 44L, 44R so that the robotic lawnmower 2 follows the wire 112 to the charging station 110. After S42, the process proceeds to S44.

[0067] In S44, the control unit 8 docks the robotic lawnmower 2 to the charging station 110 and starts charging the battery 30. The control unit 8 then continues charging the battery 30 until a predetermined charging end condition is met. This charging end condition is, for example, that the voltage value of the battery 30 detected by the battery voltage detection circuit 74 is equal to or higher than a predetermined value (e.g., 20 V). When charging of the battery 30 ends in S44, the process returns to S34.

[0068] The process shown in Fig. 9 ends when an instruction to end autonomous driving is given via the input operation unit 10 or a user's communication terminal. The process shown in Fig. 9 also ends when the main power supply of the robotic lawnmower 2 is switched off via the input operation unit 10 or a user's communication terminal.

[0069] (Operation of the robot lawnmower 2 when it encounters an obstacle) Regardless of whether the automatic height adjustment function is on or off, the control unit 8 repeatedly executes the process shown in FIG. 10 during the execution of autonomous driving.

[0070] In S52, the control unit 8 determines whether or not movement of the body 28 (see FIG. 2) relative to the base frame 26 (see FIG. 2) has been detected. Specifically, the control unit 8 determines whether or not an L signal has been output from at least one of the collision detection sensor 66 (see FIG. 4) and the lifting detection sensor 68 (see FIG. 4). If movement of the body 28 relative to the base frame 26 has not been detected (NO), the process proceeds to S54.

[0071] In S54, the control unit 8 determines that the movement of the robotic lawnmower 2 is not being impeded. After S54, the process returns to S52.

[0072] If movement of the body 28 relative to the base frame 26 is detected in S52 (YES), processing proceeds to S56. In S56, the control unit 8 determines that movement of the robotic lawnmower 2 has been impeded by an obstacle. The control unit 8 then stops the movement motors 44L, 44R (see FIG. 4) and the work motor 48 (see FIG. 4) to interrupt normal operation. Normal operation here refers to the mowing work and return operation performed by the robotic lawnmower 2 during autonomous driving. After S56, processing proceeds to S58.

[0073] In S58, the control unit 8 operates the movement motors 44L and 44R to cause the robotic lawnmower 2 to start an avoidance operation. The "avoidance operation" here refers to, for example, any of the following operations: a forward movement in which the robotic lawnmower 2 moves forward, a backward movement in which the robotic lawnmower 2 moves backward, a left turning movement in which the robotic lawnmower 2 turns left, and a right turning movement in which the robotic lawnmower 2 turns right. The "turning operation" here includes not only an operation in which the robotic lawnmower 2 turns on the spot, but also an operation in which the robotic lawnmower 2 turns while moving forward or backward. In this embodiment, the control unit 8 specifies the moving direction of the robotic lawnmower 2 before the normal operation was interrupted in S56. The control unit 8 then determines the avoidance operation to be started in S58 as an operation in which the robotic lawnmower 2 moves in the opposite direction to the moving direction before the normal operation was interrupted in S56. For example, if the robotic lawnmower 2 was moving forward before normal operation was interrupted in S56, the avoidance operation started in S58 will be moving backward. If the robotic lawnmower 2 was turning left before normal operation was interrupted in S56, the avoidance operation started in S58 will be turning right. After S58, processing proceeds to S60.

[0074] In S60, the control unit 8 judges whether or not movement of the body 28 relative to the base frame 26 is detected during the execution of the avoidance operation started immediately before (in S58 or S62). Specifically, the control unit 8 judges whether or not the signal output from at least one of the collision detection sensor 66 and the lifting detection sensor 68 is switched from an H signal to an L signal during the execution of the avoidance operation. Even if there is a sensor that continues to output an L signal from the start of the avoidance operation, the L signal output from the sensor is not switched from an H signal to an L signal during the execution of the avoidance operation. For this reason, in S60, the sensor does not judge YES. Please note that the YES / NO judgment in S60 differs from the YES / NO judgment in S52 in this respect. If movement of the body 28 relative to the base frame 26 is detected during the execution of the avoidance operation (if YES), the process proceeds to S62.

[0075] In S62, the control unit 8 causes the robotic lawnmower 2 to start an avoidance operation different from the previous avoidance operation. For example, if the previous avoidance operation was a forward movement, the control unit 8 causes the robotic lawnmower 2 to start a backward movement, a left turn movement, or a right turn movement. After S62, the process returns to S60.

[0076] If no movement of the body 28 relative to the base frame 26 is detected during the avoidance operation in S60 (if NO), the process proceeds to S64. In S64, the control unit 8 determines whether or not an overload on the movement motors 44L, 44R is detected during the avoidance operation that was started immediately before the determination of NO in S60. Specifically, the control unit 8 determines whether or not a situation in which the current value flowing through the movement motors 44L, 44R detected by the motor current detection circuit 72 (see FIG. 4) is equal to or greater than a predetermined current value (e.g., 3.0 A) continues for a predetermined time (e.g., 0.1 seconds) or more. If an overload on the movement motors 44L, 44R is detected during the avoidance operation (if YES), the process proceeds to S66.

[0077] In S66, the control unit 8 determines that the movement of the robotic lawnmower 2 (specifically, the avoidance operation) has been impeded by an obstacle. For example, if a portion of the robotic lawnmower 2 other than the body 28 (for example, the drive wheels 42L, 42R) is interfering with an obstacle, the movement of the robotic lawnmower 2 is impeded by the obstacle even though the movement of the body 28 is not detected (NO in S60). However, in this case, it is expected that the obstacle will act as a resistance and a larger load than usual will be applied to the movement motors 44L, 44R. Therefore, when the robotic lawnmower 2 of this embodiment detects an overload on the movement motors 44L, 44R (YES in S64), it determines that the movement of the robotic lawnmower 2 has been impeded by an obstacle. Also, in S66, the control unit 8 increments the number of times that it has determined that the movement of the robotic lawnmower 2 has been impeded by an obstacle by +1. This count number is reset to zero when the processing shown in Fig. 10 ends, and is therefore zero when the processing shown in Fig. 10 starts. After S66, the process proceeds to S68.

[0078] In S68, the control unit 8 determines whether the count number is equal to or greater than a predetermined number (e.g., 2 times). If the count number is less than the predetermined number (NO), the process proceeds to S62. If the count number is equal to or greater than the predetermined number (YES), the process proceeds to S70.

[0079] In S70, the control unit 8 determines that an abnormality has occurred in the robotic lawnmower 2, and stops the robotic lawnmower 2. Specifically, the control unit 8 stops the travel motors 44L, 44R and the work motor 48, and causes the robotic lawnmower 2 to wait in place. The control unit 8 also operates the display unit 14 (see FIG. 4) and the alarm unit 16 (see FIG. 4) to notify the user of the abnormality by sound or light. Alternatively, the control unit 8 communicates with a communication terminal (e.g., a smartphone) owned by the user via the communication unit 12 (see FIG. 4), and causes the communication terminal to notify the user of the abnormality. After S70, the process shown in FIG. 10 ends.

[0080] If no overload on the moving motors 44L and 44R is detected during the avoidance operation in S64 (if NO), the process proceeds to S72. In S72, the control unit 8 determines whether the avoidance operation started in S58 or S62 has ended. In this embodiment, the control unit 8 determines in advance how much to rotate each output shaft of the moving motors 44L and 44R when executing the avoidance operation. The control unit 8 monitors the amount of rotation of each output shaft of the moving motors 44L and 44R using a rotation detection sensor (resolver, etc.) provided on the moving motors 44L and 44R. For this reason, the control unit 8 determines that the avoidance operation has ended (YES) when, for example, the amount of rotation of each output shaft of the moving motors 44L and 44R after the robotic lawnmower 2 starts the avoidance operation reaches a predetermined amount of rotation. If the avoidance operation has not ended (if NO), the process returns to S60. If the avoidance operation has ended (if YES), the process proceeds to S74.

[0081] In S74, the control unit 8 determines that the movement of the robotic lawnmower 2 (specifically, the avoidance operation) is not being impeded. This is because no overload on the movement motors 44L, 44R is detected, and therefore it is presumed that the movement of the robotic lawnmower 2 has been completed without any problems. The control unit 8 then resumes the normal operation (lawnmowing or return operation) that was interrupted in S56. After S74, the processing shown in FIG. 10 ends.

[0082] (Example 2: Robotic lawnmower 202) The robotic lawnmower 202 has a configuration substantially similar to that of the robotic lawnmower 2 of the first embodiment (see Figs. 1 to 10). The robotic lawnmower 202 differs from the robotic lawnmower 2 of the first embodiment only in that the control unit 8 (see Fig. 4) executes the process shown in Fig. 11 instead of the process shown in Fig. 10. Therefore, only the process shown in Fig. 11 will be described below, and other descriptions will be omitted.

[0083] In S102, the control unit 8 determines whether or not movement of the body 28 (see FIG. 2) relative to the base frame 26 (see FIG. 2) has been detected. Specifically, the control unit 8 determines whether or not an L signal has been output from at least one of the collision detection sensor 66 (see FIG. 4) and the lifting detection sensor 68 (see FIG. 4). If movement of the body 28 relative to the base frame 26 has not been detected (NO), the process proceeds to S104.

[0084] In S104, the control unit 8 determines that there is no obstruction to the movement of the robotic lawnmower 202. After S104, the process returns to S102.

[0085] If movement of the body 28 relative to the base frame 26 is detected in S102 (YES), the process proceeds to S106. In S106, the control unit 8 determines that the movement of the robotic lawnmower 202 has been impeded by an obstacle. The control unit 8 then stops the movement motors 44L, 44R (see FIG. 4) and the work motor 48 (see FIG. 4) and interrupts normal operation (lawnmowing or returning). After S106, the process proceeds to S108.

[0086] In S108, the control unit 8 operates the travel motors 44L, 44R to cause the robotic lawnmower 202 to perform a straight movement operation (i.e., forward movement or backward movement). In this embodiment, the control unit 8 determines whether the traveling direction of the robotic lawnmower 202 was forward or backward before the normal operation was interrupted in S106. The control unit 8 then determines the straight movement operation to be performed in S108 as an operation in which the robotic lawnmower 202 moves in the opposite direction to the traveling direction before the normal operation was interrupted in S106. For example, if the robotic lawnmower 202 was performing a forward movement operation before the normal operation was interrupted in S106, the straight movement operation to be performed in S108 is a backward movement operation. When the straight movement operation ends, the process proceeds to S110.

[0087] In S110, the control unit 8 operates the travel motors 44L, 44R to cause the robotic lawnmower 202 to start a turning operation (i.e., a left turning operation or a right turning operation). At this time, the control unit 8 randomly determines the turning direction and target turning angle of the robotic lawnmower 202. The target turning angle is determined to be an angle within a range of, for example, 10 degrees to 180 degrees. The control unit 8 controls the travel motors 44L, 44R so as to turn the robotic lawnmower 202 by the determined target turning angle in the determined turning direction. After S110, the process proceeds to S112.

[0088] In S112, the control unit 8 determines whether the turning angle of the robotic lawnmower 202 since it started its turning operation has reached the target turning angle. The control unit 8 is configured to measure the turning angle of the robotic lawnmower 202 since it started its turning operation using an angular velocity detection sensor 70 (see FIG. 4) provided on the base frame 26. If the turning angle of the robotic lawnmower 202 since it started its turning operation has not reached the target turning angle (NO), the process proceeds to S114.

[0089] In S114, the control unit 8 determines whether the time that has elapsed since the robotic lawnmower 202 started turning in S110 is equal to or greater than a predetermined time (e.g., 6.0 seconds). If the time that has elapsed is less than the predetermined time (NO), the process returns to S112. If the time that has elapsed is equal to or greater than the predetermined time (YES), the process proceeds to S116.

[0090] In S116, the control unit 8 determines that the movement (specifically, the turning operation) of the robotic lawnmower 202 is impeded by an obstacle. For example, if a portion of the robotic lawnmower 202 other than the body 28 (for example, the drive wheels 42L, 42R) is interfering with an obstacle, the movement of the robotic lawnmower 202 is impeded by the obstacle even though the movement of the body 28 is not detected (NO in S60). In this case, it is expected that the obstacle will act as a resistance and the turning angle of the robotic lawnmower 202 will not change at all even though the moving motors 44L, 44R are operating. Therefore, in this embodiment, the robotic lawnmower 202 determines that the movement of the robotic lawnmower 202 is impeded by an obstacle if the situation in which the turning angle of the robotic lawnmower 202 does not reach the target turning angle continues (YES in S114). Also, in S116, the control unit 8 increments the number of times it has determined that the movement of the robotic lawnmower 202 has been impeded by an obstacle by +1. This count is reset to zero when the processing shown in Fig. 11 ends, so it is zero when the processing shown in Fig. 11 starts. After S116, the processing proceeds to S118.

[0091] In S118, the control unit 8 determines whether the count number is equal to or greater than a predetermined number (for example, 2 times). If the count number is less than the predetermined number (NO), the process proceeds to S120.

[0092] In S120, the control unit 8 causes the robotic lawnmower 202 to start a turning operation in the opposite direction to the previous turning operation. For example, if the previous turning operation was a left turning operation, the control unit 8 causes the robotic lawnmower 202 to start a right turning operation. After S120, the process returns to S112.

[0093] If the count number is equal to or greater than the predetermined number in S118 (YES), the process proceeds to S122. In S122, the control unit 8 determines that an abnormality has occurred in the robotic lawnmower 202 and stops the robotic lawnmower 202. Specifically, the control unit 8 stops the travel motors 44L, 44R and the work motor 48, and causes the robotic lawnmower 202 to wait in place. The control unit 8 also operates the display unit 14 (see FIG. 4) and the alarm unit 16 (see FIG. 4) to notify the user of the occurrence of an abnormality by sound or light. Alternatively, the control unit 8 communicates with a communication terminal (e.g., a smartphone) owned by the user via the communication unit 12 (see FIG. 4) and causes the communication terminal to notify the user of the occurrence of an abnormality. After S122, the process shown in FIG. 11 ends.

[0094] In S112, if the turning angle of the robotic lawnmower 202 since the robotic lawnmower 202 started its turning operation has reached the target turning angle (YES), the process proceeds to S124.

[0095] In S124, the control unit 8 determines that the movement (specifically, the turning operation) of the robotic lawnmower 202 is not hindered by an obstacle. This is because the turning angle of the robotic lawnmower 202 has reached the target turning angle, and therefore it is presumed that the movement of the robotic lawnmower 202 has ended smoothly. The control unit 8 also resumes the normal operation (lawnmowing work or return operation) that was interrupted in S106. After S124, the processing shown in FIG. 11 ends.

[0096] (Example 3: Robotic lawnmower 302) The robotic lawnmower 302 has a configuration similar to that of the robotic lawnmower 2 of the first embodiment (see Figs. 1-10). The robotic lawnmower 302 differs from the robotic lawnmower 2 of the first embodiment only in that the control unit 8 (see Fig. 4) executes the process shown in Fig. 12 instead of the process shown in Fig. 10. The process shown in Fig. 12 reuses the process shown in Fig. 10, with S60 and S64 replaced by S160 and S164. Therefore, in the following, only S160 and S164 of the process shown in Fig. 12 will be described, and the rest of the description will be omitted.

[0097] S160 is executed after S58 or after S62. In S160, the control unit 8 judges whether or not movement of the body 28 relative to the base frame 26 is detected during the execution of the avoidance operation started immediately before (S58 or S62). Specifically, the control unit 8 judges whether or not a signal output from at least one of the collision detection sensor 66 (see FIG. 4) and the lifting detection sensor 68 (see FIG. 4) is switched from an H signal to an L signal during the execution of the avoidance operation. Note that even if there is a sensor that continues to output an L signal from the start of the avoidance operation, the L signal output from the sensor is not switched from an H signal to an L signal during the execution of the avoidance operation. For this reason, in S160, the sensor will not judge YES. Please note that the YES / NO judgment in S160 is different from the YES / NO judgment in S52 in this respect. If movement of the body 28 relative to the base frame 26 is not detected during the execution of the avoidance operation (in the case of NO), the process proceeds to S72. If movement of the body 28 relative to the base frame 26 is detected during the execution of the avoidance operation (YES), the process proceeds to S164.

[0098] In S164, the control unit 8 judges whether or not an overload on the movement motors 44L, 44R is detected during the execution of the avoidance operation started immediately before the judgment in S160 is NO. Specifically, the control unit 8 judges whether or not a situation in which the current value flowing through the movement motors 44L, 44R detected by the motor current detection circuit 72 (see FIG. 4) is equal to or greater than a predetermined current value (e.g., 3.0 A) continues for a predetermined time (e.g., 0.1 seconds) or more. If an overload on the movement motors 44L, 44R is not detected during the execution of the avoidance operation (if NO), the process proceeds to S62. If an overload on the movement motors 44L, 44R is detected during the execution of the avoidance operation (if YES), the process proceeds to S66.

[0099] Even if the movement of the body 28 is detected (YES in S160), if an overload on the travel motors 44L, 44R is not detected (NO in S164), it is possible, but not certain, that the movement of the robotic lawnmower 302 is hindered by an obstacle. In this case, the robotic lawnmower 302 of this embodiment postpones the determination of whether the movement of the robotic lawnmower 302 is hindered by an obstacle and performs a different avoidance operation. Then, if the movement of the body 28 is detected (YES in S160) and an overload on the travel motors 44L, 44R is detected (YES in S164), it determines that the movement of the robotic lawnmower 302 is hindered by an obstacle. This makes it possible to prevent the control unit 8 from making an erroneous determination (determining that the movement of the robotic lawnmower 302 is hindered by an obstacle when in fact the movement of the robotic lawnmower 302 is not hindered by an obstacle).

[0100] (Example 4: Robotic lawnmower 402) The robotic lawnmower 402 has a configuration substantially similar to that of the robotic lawnmower 2 of the first embodiment (see Figs. 1-10). The robotic lawnmower 402 differs from the robotic lawnmower 2 of the first embodiment only in that the control unit 8 (see Fig. 4) executes the process shown in Fig. 13 instead of the process shown in Fig. 7. Therefore, only the process shown in Fig. 13 will be described below, and other descriptions will be omitted.

[0101] In S202, the control unit 8 operates the height adjustment motor 54 (see FIG. 2) to adjust the height h of the cutting blade 46 (see FIG. 2) to the initial height previously set by the user. After S202, the process proceeds to S204.

[0102] In S204, the control unit 8 determines whether or not the current time is within the work time zone. If the current time is not within the work time zone (NO), the process proceeds to S206.

[0103] In S206, the control unit 8 causes the robotic lawnmower 402 to wait at the charging station 110 (see FIG. 1). If the robotic lawnmower 402 is not at the charging station 110 when S206 is started, the control unit 8 causes the robotic lawnmower 402 to return to the charging station 110. Specifically, with the working motor 48 (see FIG. 4) stopped, the control unit 8 operates the movement motors 44L, 44R (see FIG. 4) so ​​that the robotic lawnmower 402 follows the wire 112 to the charging station 110. After that, with the working motor 48 and the movement motors 44L, 44R stopped, the control unit 8 causes the robotic lawnmower 402 to wait at the charging station 110. After S206, the process returns to S204.

[0104] If the current time is within the work time zone in S204 (YES), the process proceeds to S208. In S208, the control unit 8 starts mowing work with the robotic lawnmower 402. Specifically, the control unit 8 operates the movement motors 44L, 44R to move the robot body 4, while operating the work motor 48 to cut the grass with the cutting blade 46 (see FIG. 2). This causes the height of the grass to be aligned to the height h of the cutting blade 46. After S208, the process proceeds to S210.

[0105] In S210, the control unit 8 determines whether a predetermined grass height uniformity condition is met. The grass height uniformity condition here is substantially the same as that described in the first embodiment, and therefore will not be described here. If the grass height uniformity condition is met (YES), the process proceeds to S212.

[0106] In S212, the control unit 8 determines whether the current height h of the blade 46 has reached the target height preset by the user. If the height h of the blade 46 has not reached the target height (i.e., the height h of the blade 46 is higher than the target height) (NO), the process proceeds to S214.

[0107] In S214, the control unit 8 operates the height adjustment motor 54 to lower the height h of the cutting blade 46 by a predetermined amount (for example, 5 mm).

[0108] If the height h of the cutting blade 46 has reached the target height in S212 (YES), the process proceeds to S216. In S216, the control unit 8 turns on a target height reached flag, which indicates that the height of the grass in the work area WA has been set to the target height overall.

[0109] If the uniform grass height condition is not met in S210 (if NO), after S214 or after S216, processing proceeds to S218. In S218, the control unit 8 determines whether or not a predetermined return condition is met. The return condition here is substantially the same as that described in the first embodiment, and therefore description thereof will be omitted. If the return condition is not met (if NO), processing returns to S210. If the return condition is met (if YES), processing proceeds to S220.

[0110] In S220, the control unit 8 ends the mowing operation started in S208 and returns the robotic lawnmower 402 to the charging station 110. Specifically, with the work motor 48 stopped, the control unit 8 operates the travel motors 44L, 44R so that the robotic lawnmower 402 follows the wire 112 to the charging station 110. After S220, the process proceeds to S222.

[0111] In S222, the control unit 8 docks the robotic lawnmower 402 to the charging station 110 and starts charging the battery 30 (see FIG. 4). The control unit 8 then continues charging the battery 30 until a predetermined charging end condition is met. The charging end condition is, for example, that the voltage value of the battery 30 detected by the battery voltage detection circuit 74 (see FIG. 4) is equal to or higher than a predetermined value (e.g., 20 V). When charging of the battery 30 ends in S222, the process proceeds to S224.

[0112] In S224, the control unit 8 determines whether the target height reach flag is on. If the target height reach flag is off (if NO), the process returns to S204. If the target height reach flag is on (if YES), the process proceeds to S226.

[0113] In S226, the control unit 8 notifies the user that the height of the grass in the work area WA has been generally aligned to the target height. The control unit 8 communicates with the user's communication terminal via the communication unit 12 (see FIG. 4), for example, and causes the communication terminal to notify the user that the height of the grass in the work area WA has been generally aligned to the target height. After S226, the process shown in FIG. 13 ends.

[0114] (Modification) The working robot may be a robot other than the robotic lawnmower 2, 202, 302, 402. For example, the working robot may be a robot vacuum cleaner equipped with a brush and / or a suction mechanism for collecting debris such as dust. In this case, the work motor 48 may be used as a motor for driving the brush and / or the suction mechanism. The working robot may also be a rebar binding robot equipped with a rebar binding mechanism for binding the intersections of multiple rebars. In this case, the work motor 48 may be used as a motor for driving the rebar binding mechanism.

[0115] A power cord connected to an external power source (e.g., a commercial power source) may be attached to the robotic lawnmower 2, 202, 302, 402. In this case, the robotic lawnmower 2, 202, 302, 402 may be configured to operate using power supplied from the external power source via the power cord.

[0116] The robotic lawnmower 2, 202, 302, 402 may not be equipped with the battery 30. Instead, a rechargeable battery pack such as a lithium-ion battery may be detachably attached to the robot body 4. In this case, the robotic lawnmower 2, 202, 302, 402 may be configured to operate using power supplied from the battery pack.

[0117] The moving unit 18 may be equipped with other moving mechanisms (e.g., crawlers, side steppers) instead of the casters 40L, 40R and the drive wheels 42L, 42R. The side stepper here is a mechanism for moving the robot body 4 in the left-right direction. When the moving unit 18 is equipped with a side stepper, the avoidance operation may be an operation for moving the robot body 4 in the left or right direction by the side stepper.

[0118] The feedback condition used in S14 of Fig. 7 does not have to include the second feedback condition. Instead, the feedback condition used in S14 of Fig. 7 may include a third feedback condition in which the uniform grass height flag is on and the remaining charge of the battery 30 is relatively high (for example, the voltage value of the battery 30 is 19 V or higher).

[0119] The amount of descent of the height h of the cutting blade 46 in S24 of FIG. 7 (or S214 of FIG. 13) does not have to be a predetermined amount. For example, the control unit 8 may randomly determine the amount of descent of the height h of the cutting blade 46. Alternatively, the control unit 8 may reduce the amount of descent of the height h of the cutting blade 46 the next time S24 (or S214) is executed compared to the amount of descent of the height h of the cutting blade 46 the first time S24 (or S214) is executed during autonomous driving. Alternatively, the amount of descent of the height h of the cutting blade 46 may be changeable by the user via the input operation unit 10 or a communication terminal.

[0120] The robotic lawnmower 2, 202, 302, 402 may have a mapping function for constructing map information of the working area WA. For example, the control unit 8 may construct the map information by acquiring the movement history of the robotic lawnmower 2, 202, 302, 402 using a GPS. The map information of the working area WA may include the area of ​​the working area WA. This allows the control unit 8 to acquire the area of ​​the working area WA even if the user does not set the area of ​​the working area WA.

[0121] 10, after S58 or after S62, the process may skip S60 and proceed to S64. In other words, while the robotic lawnmower 2 is performing an avoidance operation, the control unit 8 may determine whether or not the movement of the robotic lawnmower 2 is being impeded by an obstacle based only on the detection result of the motor current detection circuit 72, without based on the detection results of the collision detection sensor 66 and the lifting detection sensor 68.

[0122] 10, if movement of the body 28 relative to the base frame 26 is detected while an avoidance operation is being performed (YES), the process may proceed to S66. That is, the control unit 8 may determine that the movement of the robotic lawnmower 2 has been impeded by an obstacle even if movement of the body 28 is detected while an avoidance operation is being performed.

[0123] 10 (or S160 in FIG. 12), the control unit 8 may determine whether or not an L signal is being output from at least one of the collision detection sensor 66 and the lifting detection sensor 68, instead of determining whether or not the signal output from at least one of the collision detection sensor 66 and the lifting detection sensor 68 has switched from an H signal to an L signal during execution of the avoidance operation. That is, the control unit 8 may determine YES if the L signal is simply being output, even if there is no switch from an H signal to an L signal.

[0124] 10 (or S164 in FIG. 12), the control unit 8 may determine whether the current value flowing through the travel motors 44L, 44R detected by the motor current detection circuit 72 has reached or exceeded a predetermined current value, instead of determining whether the state in which the current value flowing through the travel motors 44L, 44R detected by the motor current detection circuit 72 has remained at or above a predetermined current value for or longer than a predetermined time. That is, the control unit 8 may determine YES at the timing when the current value flowing through the travel motors 44L, 44R detected by the motor current detection circuit 72 has reached or exceeded a predetermined current value.

[0125] The robotic lawnmower 2, 202, 302, 402 may further include an inclination angle detection sensor (e.g., a gyro sensor) that detects the inclination angle of the base frame 26 with respect to the horizontal direction. In this case, in S52 and S60 of Fig. 10 (or S102 of Fig. 11, and S52 and S160 of Fig. 12), the control unit 8 may determine whether the inclination angle of the base frame 26 detected by the inclination angle detection sensor exceeds a predetermined angle threshold (e.g., 90 degrees). Alternatively, the control unit 8 may determine whether an L signal is output from at least one of the collision detection sensor 66 (see Fig. 4) and the lifting detection sensor 68 (see Fig. 4) and whether the inclination angle of the base frame 26 detected by the inclination angle detection sensor exceeds a predetermined angle threshold. 10 (or S164 in FIG. 12), the control unit 8 may determine whether the tilt angle of the base frame 26 detected by the tilt angle detection sensor exceeds a predetermined angle threshold (e.g., 90 degrees). Alternatively, the control unit 8 may determine whether an overload on the travel motors 44L, 44R is detected and the tilt angle of the base frame 26 detected by the tilt angle detection sensor exceeds a predetermined angle threshold. In this way, the control unit 8 may determine that the movement of the robotic lawnmower 2, 202, 302, 402 is hindered by an obstacle even when the tilt angle of the base frame 26 is an excessively large value.

[0126] (Features of the embodiment) As described above, in one or more embodiments, the robot lawnmower 2, 202, 302, 402 (an example of a working robot) performs work while moving autonomously. The robot lawnmower 2, 202, 302, 402 includes the robot body 4 including the base frame 26 (an example of a base) and the body 28 (an example of a bumper) supported by the base frame 26, the working unit 20 supported by the base frame 26, the drive wheels 42L, 42R (an example of a moving mechanism) that move the base frame 26, the moving motors 44L, 44R that drive the drive wheels 42L, 42R, the collision detection sensor 66 and / or the lifting detection sensor 68 (an example of a first detection unit) that detects the force applied to the body 28 or the displacement of the body 28 relative to the base frame 26, the motor current detection circuit 72 (or the angular velocity detection sensor 70 that detects the angular velocity of the base frame 26) (an example of a second detection unit) that detects the state of the moving motors 44L, 44R, and the control unit 8. The control unit 8 is configured to be able to determine whether or not the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by an obstacle based on the detection results of the collision detection sensor 66 and / or lifting detection sensor 68 and the detection results of the motor current detection circuit 72 (or the angular velocity detection sensor 70).

[0127] According to the above configuration, the control unit 8 of the robotic lawnmower 2, 202, 302, 402 can determine whether the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by an obstacle not only based on the force applied to the body 28 or the displacement of the body 28 relative to the base frame 26, but also based on the state of the travel motors 44L, 44R (or the angular velocity of the base frame 26). This improves the accuracy of determining whether the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by an obstacle, allowing the robotic lawnmower 2, 202, 302, 402 to easily avoid the obstacle. Therefore, according to the above configuration, the work of the robotic lawnmower 2, 202, 302, 402 can proceed smoothly.

[0128] In one or more embodiments, the control unit 8 performs a first obstruction determination process (S52, S54, S56 in FIG. 10) (or S102, S104, S106 in FIG. 11) (or S52, S54, S56 in FIG. 12) to determine whether the movement of the robotic lawnmower 2, 202, 302, 402 is obstructed by an obstacle based on at least the detection results of the collision detection sensor 66 and / or the lifting detection sensor 68, and controls the movement motors 44L, 44R so that the robotic lawnmower 2, 202, 302, 402 performs an avoidance operation to move around the obstacle after it is determined in the first obstruction determination process that the movement of the robotic lawnmower 2, 202, 302, 402 is obstructed by an obstacle. and a second obstruction determination process (S60, S64, S66, S72, S74 in FIG. 10) (or S112, S112, S114, S116, S124 in FIG. 11) (or S160, S164, S66, S72, S74 in FIG. 12) that determines whether the movement of the robotic lawnmower 2, 202, 302, 402 is being obstructed by an obstacle based on at least the detection result of the motor current detection circuit 72 (or the angular velocity detection sensor 70) while the robotic lawnmower 2, 202, 302, 402 is performing an avoidance operation.

[0129] In the above configuration, when the robotic lawnmower 2, 202, 302, 402 (specifically the body 28) comes into contact with an obstacle, the control unit 8 determines that the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by the obstacle, and causes the robotic lawnmower 2, 202, 302, 402 to perform an avoidance operation. However, as the robotic lawnmower 2, 202, 302, 402 performs an avoidance operation, a part of the robotic lawnmower 2, 202, 302, 402 other than the body 28 may come into contact with the obstacle, causing the movement of the robotic lawnmower 2, 202, 302, 402 to be hindered by the obstacle. In this case, the detection results of the collision detection sensor 66 and / or the lifting detection sensor 68 (the force received by the body 28 or the displacement of the body 28 relative to the base frame 26) do not show any particular indication that the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by an obstacle. For this reason, if the control unit 8 determines whether the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by an obstacle based only on the collision detection sensor 66 and / or the lifting detection sensor 68 while the robotic lawnmower 2, 202, 302, 402 is performing an avoidance operation, the determination result may be erroneous. In contrast, according to the above configuration, while the robotic lawnmower 2, 202, 302, 402 is performing an avoidance operation, the control unit 8 determines whether the movement of the robotic lawnmower 2, 202, 302, 402 is being hindered by an obstacle based at least on the motor current detection circuit 72 (or the angular velocity detection sensor 70). This makes it possible to prevent erroneous determination results as to whether or not an obstacle is obstructing the movement of the robotic lawnmower 2, 202, 302, 402. Therefore, with the above configuration, it is possible to accurately determine whether or not an obstacle is obstructing the movement of the robotic lawnmower 2, 202, 302, 402.

[0130] In one or more embodiments, the avoidance maneuver includes a turning maneuver in which the robotic lawnmower 2, 202, 302, 402 turns.

[0131] According to the above configuration, the avoidance operation can be made relatively complicated.

[0132] In one or more embodiments, the avoidance maneuver includes a straight ahead movement in which the robotic lawnmower 2, 202, 302, 402 moves in a straight line.

[0133] If the avoidance operation were to consist only of a turning operation, there is a possibility that the robotic lawnmower 2, 202, 302, 402 would not move away from the obstacle after coming into contact with it. In this case, the robotic lawnmower 2, 202, 302, 402 would take time to avoid the obstacle, and the robotic lawnmower 2, 202, 302, 402 may not be able to perform its work smoothly. According to the above configuration, the avoidance operation includes a straight movement operation, so that the robotic lawnmower 2, 202, 302, 402 is more likely to move away from the obstacle after coming into contact with it. This reduces the time required for the robotic lawnmower 2, 202, 302, 402 to avoid the obstacle, and the robotic lawnmower 2, 202, 302, 402 can perform its work smoothly.

[0134] In one or more embodiments, the state of the movement motors 44L, 44R includes a current flowing through the movement motors 44L, 44R. The second detection unit includes a motor current detection circuit 72 (an example of a motor current detection unit) that detects a current flowing through the movement motors 44L, 44R.

[0135] If the movement motors 44L, 44R are operated while the movement of the robotic lawnmower 2, 302, 402 is hindered by an obstacle, the obstacle acts as resistance, and a larger load than normal is applied to the movement motors 44L, 44R. In this case, it is expected that the current flowing through the movement motors 44L, 44R will be larger than normal. With the above configuration, while the movement motors 44L, 44R are being operated, the control unit 8 can estimate the load applied to the movement motors 44L, 44R from the current flowing through the movement motors 44L, 44R, and determine whether the movement of the robotic lawnmower 2, 302, 402 is being hindered by an obstacle.

[0136] In one or more embodiments, the control unit 8 determines that the movement of the robotic lawnmower 2, 302, 402 is being obstructed by an obstacle when the detection value of the motor current detection circuit 72 remains above a predetermined current value for a predetermined period of time or longer.

[0137] In response to determining that the movement of the robotic lawnmower 2, 302, 402 is hindered by an obstacle, the control unit 8 may cause the robotic lawnmower 2, 302, 402 to perform an avoidance operation to move around the obstacle. In this configuration, if it is determined that the movement of the robotic lawnmower 2, 302, 402 is hindered by an obstacle at the timing when the detection value of the motor current detection circuit 72 becomes equal to or greater than a predetermined current value, there is a risk that an avoidance operation will be performed unnecessarily. This is because the robotic lawnmower 2, 302, 402 may be able to avoid the obstacle by normal operation without performing an avoidance operation. According to the above configuration, if the detection value of the motor current detection circuit 72 remains equal to or greater than the predetermined current value for a predetermined period of time or more, it is determined that the movement of the robotic lawnmower 2, 302, 402 is hindered by an obstacle. Therefore, an avoidance operation is performed only if the state in which the movement of the robotic lawnmower 2, 302, 402 is hindered by an obstacle continues for a certain period of time. This makes it possible to prevent unnecessary avoidance operations, thereby allowing the robotic lawnmower 2, 302, 402 to carry out its work smoothly.

[0138] In one or more embodiments, the working unit 20 includes a cutting blade 46 for cutting the grass. The working robot functions as a robotic lawnmower 2, 202, 302, 402.

[0139] According to the above configuration, the robotic lawnmower 2, 202, 302, 402 can smoothly carry out its work. [Explanation of symbols]

[0140] 2: robot lawnmower, 4: robot body, 6: power supply unit, 8: control unit, 10: input operation unit, 12: communication unit, 14: display unit, 16: alarm unit, 18: moving unit, 20: working unit, 22: height adjustment unit, 24: detection unit, 26: base frame, 28: body, 30: battery, 32: charging interface, 34: processor, 36: memory, 38: power supply circuit, 40L: caster, 40R: caster, 42L: drive wheel, 42R: drive wheel, 44L: moving motor, 44R: moving motor, 46: cutting blade, 48: working motor, 50: output shaft, 52: height adjustment Mechanism, 54: Height adjustment motor, 56: Female thread, 58: Outer cylinder, 60: Male thread, 62: Inner cylinder, 64: Wire detection sensor, 66: Collision detection sensor, 68: Lifting detection sensor, 70: Angular velocity detection sensor, 72: Motor current detection circuit, 74: Battery voltage detection circuit, 76: Magnet, 78: Metal plate, 100: Site, 102: House, 104: Pond, 106: Road, 110: Charging station, 112: Wire, 202: Robotic lawnmower, 302: Robotic lawnmower, 402: Robotic lawnmower, G: Ground, TT: Threshold table, WA: Working area

Claims

1. A working robot that performs work while moving autonomously, a robot body including a base and a bumper supported by the base; A working unit supported by the base; A moving mechanism that moves the base; A movement motor that drives the movement mechanism; a first detection unit that detects a force applied to the bumper or a displacement of the bumper relative to the base; a second detection unit that detects an angular velocity of the base or a state of the movement motor; A control unit, A working robot, wherein the control unit is configured to be able to determine whether or not movement of the working robot is being obstructed by an obstacle based on the detection result of the first detection unit and the detection result of the second detection unit.

2. The control unit is a first obstruction determination process for determining whether or not movement of the work robot is being obstructed by the obstacle based on at least a detection result of the first detection unit; an avoidance process of operating the movement motor so that the work robot performs an avoidance operation for moving while avoiding the obstacle after it is determined in the first obstruction determination process that movement of the work robot is obstructed by the obstacle; 2. The working robot of claim 1, further comprising: a second obstruction determination process for determining whether or not movement of the working robot is being obstructed by the obstacle based on at least a detection result of the second detection unit while the working robot is performing the avoidance operation.

3. The working robot of claim 2 , wherein the avoidance operation includes a turning operation in which the working robot turns.

4. The working robot according to claim 2 or 3, wherein the avoidance movement includes a straight movement movement in which the working robot moves straight.

5. the state of the movement motor includes a current flowing through the movement motor; The working robot according to claim 1 , wherein the second detection unit includes a motor current detection unit that detects a current flowing through the movement motor.

6. 6. The working robot of claim 5, wherein the control unit determines that movement of the working robot is being impeded by the obstacle when a state in which the detection value of the motor current detection unit is equal to or greater than a predetermined current value continues for a predetermined period of time or longer.

7. The working unit is provided with a cutting blade for cutting grass, The working robot of claim 1 , which functions as a robotic lawnmower.

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