Work vehicle, control method, and program

Abstract

To perform position control more accurately.SOLUTION: A working vehicle 10 is a working vehicle whose position is controlled by unwinding wires R1, R2 whose one end is supported by a fixed object, and includes: an unwinding part provided corresponding to the wires R1, R2 and unwinding the wires R1, R2; gas springs 25 for applying tension to wires R1, R2; detection switches 26 for detecting slack of tension in the wires R1, R2 by detecting an expansion / contraction state of the gas springs 25; and a control part 50 for performing control related to the unwinding part. Based on the detection of the slack of tension in the wire R1 or the wire R2 by the detection switch 26, the unwinding part 50 is controlled so as to wind the wire R1 or the wire R2 in which the slack is detected.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] One aspect of the present invention relates to a work vehicle, a control method, and a program. [Background technology]

[0002] There are many small farm fields in mountainous areas, and the accompanying ridges are large, making it an issue to reduce the labor and effort required for ridge maintenance. Ridge maintenance is an important task for maintaining the ridges and preventing weeds and pests from entering the farmland, but it is anticipated that ridge management will become difficult due to a shortage of workers and an aging workforce, making it difficult to continue farming. Ridge maintenance is work that is not directly linked to production, so there is a need to reduce the labor and make the work more efficient.

[0003] Known examples of work vehicles for performing tasks such as mowing in relation to levee management include those described in Patent Documents 1 and 2. Patent Document 1 discloses a work vehicle that uses tension in a rope body, one end of which is supported by a fixed object, to reel in and let out, thereby propelling the vehicle body. Patent Document 2 discloses a vehicle used for mowing on slopes that determines the relative position of a mower from the direction of travel of the mower and the payout angle and payout amount of two rope bodies. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-201560 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-167492 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-described work vehicle, the position of the work vehicle is controlled according to the amount of tension in the rope. In such a work vehicle, if the rope becomes loose, tangled, or breaks, for example, it may not be possible to properly control the position of the work vehicle (stable autonomous control through precise control of the length of the rope). If the rope becomes tangled or breaks, there is a risk that the work vehicle will fall outside the designated area.

[0006] One aspect of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a work vehicle, a control method, and a program that are capable of performing position control more accurately. [Means for solving the problem]

[0007] A work vehicle according to one aspect of the present invention is a work vehicle whose position is controlled by winding a rope body having one end supported by a fixed object, and is equipped with a winding section provided corresponding to the rope body and winding the rope body, a rope side elastic body that applies tension to the rope body, a detection switch that detects slack in tension in the rope body by detecting the expansion / contraction state of the rope side elastic body, and a control section that performs control related to the winding section, and the control section controls the winding section so that the rope body for which slack has been detected is wound up based on the detection switch detecting slack in tension in the rope body.

[0008] In a work vehicle according to one aspect of the present invention, tension is applied to the rope body by the rope-side elastic body, thereby effectively preventing the rope body from loosening (i.e., a deterioration in the accuracy of position control of the work vehicle). Also, in a work vehicle according to one aspect of the present invention, slack in the rope body is detected by detecting the stretched or contracted state of the rope-side elastic body using a detection switch. This makes it possible to properly detect that the rope body is loose. Furthermore, in a work vehicle according to one aspect of the present invention, the control unit controls the winding unit so that the rope body in which slack is detected is wound up, thereby properly eliminating slack in the rope body and improving the accuracy of position control of the work vehicle. As described above, a work vehicle according to one aspect of the present invention can perform position control more accurately.

[0009] The winding / unwinding unit includes a reel that rotates with the rope wound around it to unwind the rope, a motor that is a drive source for rotating the reel, and a motor drive control mechanism that controls the drive of the motor, and the control unit may output a control signal to the motor drive control mechanism so that the rope in which slack has been detected is wound by the reel. By controlling the motor drive control mechanism in this way, slack in the rope can be more reliably eliminated.

[0010] The work vehicle may further include a retainer that retains the rope wound around the reel. This configuration prevents the rope from rising up on the reel, allowing for more accurate position control of the work vehicle.

[0011] The restraining portion may have a roller that holds down the rope body while rotating as the rope body is unwound as the reel rotates, and a roller-side elastic body that applies tension to the roller to press it in the reel direction. In this way, the roller-side elastic body presses the roller in the reel direction, thereby more reliably preventing the rope body from swelling up on the reel.

[0012] The work vehicle may further include an encoder that detects the rotation of the roller, and the control unit may determine the control content based on a control signal output to the motor drive control mechanism and the rotation status of the roller detected by the encoder. By detecting the rotation of the roller, which rotates as the rope body is wound and holds down the rope body, the amount of winding of the rope body can be accurately obtained. Then, by determining the control content taking into consideration the control signal and the actual rotation status of the roller (the amount of winding of the rope body), the control content can be appropriately determined based on the actual amount of winding of the rope body in response to a command.

[0013] The control unit may issue a notification urging repair if looseness is detected in the first state in which the encoder does not detect rotation of the roller despite outputting a control signal to the motor drive control mechanism to rotate the motor. In this way, if the roller is not rotating in a situation in which it is assumed that the roller is rotating and looseness of the rope body is detected, it is necessary to stop processing and repair the malfunction, but by issuing a notification urging repair as described above, repair can be carried out quickly.

[0014] The control unit may determine that normal processing is possible if no slack is detected in the second state in which the winding direction of the rope body corresponding to the rotation direction of the motor instructed by the control signal output to the motor drive control mechanism and the winding direction of the rope body corresponding to the rotation direction of the roller detected by the encoder match. In this way, if the expected and actual winding directions of the rope body match and no slack is detected, it is believed that no abnormality has occurred, and by determining that normal processing is possible, the work vehicle can be smoothly controlled.

[0015] When slack is detected in the second state, the control unit may output a control signal to the motor drive control mechanism so that the rope body in which slack has been detected is wound by the reel, and may determine that the slack has been eliminated and normal processing is now possible when the rotation direction of the roller detected by the encoder is the direction in which the rope body is wound and slack is no longer detected. In this way, even if slack has been detected once, by determining that normal processing is now possible when the slack is eliminated by winding the rope body, normal processing can be smoothly restored after slack detection.

[0016] In a third state in which the winding direction of the rope body corresponding to the rotation direction of the motor instructed by the control signal output to the motor drive control mechanism does not match the winding direction of the rope body corresponding to the rotation direction of the roller detected by the encoder, the control unit outputs a control signal to the motor drive control mechanism so that the rope body is wound by the reel, and if the rotation direction of the roller detected by the encoder is not the direction in which the rope body is wound, a warning may be issued to prompt repair. In this way, when the expected and actual winding directions of the rope body do not match, if the control signal is output so that the rope body is wound, but the rotation direction of the roller is not the direction in which the rope body is wound, it is necessary to stop processing and perform repairs, but by issuing a warning to prompt repairs as described above, the repairs can be performed quickly.

[0017] The control unit may control the corresponding unwinding unit so that the rope body in which slack is detected is wound only when the detection switch detects slack a predetermined number of times or more within a predetermined time. This makes it possible to prevent the rope body from being wound when slack is only detected temporarily by the switch and winding of the rope body is not necessary. In other words, it is possible to stabilize the switch behavior.

[0018] In one aspect of the present invention, a control method for a work vehicle includes a winding unit that winds and unwinds a rope body, one end of which is supported by a fixed object, a rope-side elastic body that applies tension to the rope body, and a detection switch that detects slack in the tension in the rope body by detecting the expansion and contraction state of the rope-side elastic body. A computer that controls the work vehicle controls the corresponding winding unit so that the rope body for which slack is detected is wound up based on the detection switch detecting slack in the tension in the rope body. This control method allows for more accurate position control of the work vehicle.

[0019] A program according to one aspect of the present invention causes a computer that controls a work vehicle equipped with a winding unit that winds and unwinds a rope body one end of which is supported by a fixed object, a rope-side elastic body that applies tension to the rope body, and a detection switch that detects slack in the tension of the rope body by detecting the expansion and contraction state of the rope-side elastic body to control the corresponding winding unit so that the rope body for which slack has been detected is wound up based on the detection switch detecting slack in the tension of the rope body. Such a program enables more accurate position control of the work vehicle. [Effects of the Invention]

[0020] According to one aspect of the present invention, it is possible to provide a work vehicle, a control method, and a program that are capable of performing position control more accurately. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram showing an image of a work performed by a work vehicle according to an embodiment of the present invention; [Figure 2] 1 is a schematic diagram showing an image of a work performed by a work vehicle according to an embodiment of the present invention; [Figure 3] FIG. 1 is a perspective view showing a configuration of a work vehicle. [Figure 4] 10A and 10B are diagrams illustrating tension on a wire. [Figure 5] FIG. 2 is a block diagram showing the functions of a control unit. [Figure 6] FIG. 2 is a block diagram illustrating a hardware configuration of a control unit. [Figure 7] FIG. 1 is a diagram illustrating a position estimation technique. [Figure 8] 10 is a flowchart showing a processing procedure in a work vehicle. [Figure 9] 10 is a flowchart showing a processing procedure in a work vehicle. [Figure 10] 10 is a flowchart showing a processing procedure in a work vehicle. [Figure 11] 10 is a flowchart showing a processing procedure in a work vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of a work vehicle, a work vehicle control method, and a program will be described with reference to the drawings. In the description, identical elements or elements having identical functions are designated by the same reference numerals, and redundant description will be omitted.

[0023] 1 and 2 are schematic diagrams showing an image of a work image of a work vehicle 10 according to this embodiment. FIG. 1 is a perspective view of the work vehicle 10 positioned in a work area W on a slope. FIG. 2 is a side view of the work vehicle 10 positioned in the work area W on a slope. As shown in FIGS. 1 and 2, the work vehicle 10 is a vehicle for mowing the grass in the work area W on a slope while traveling. The slope may be, for example, a ridge in a rice paddy, but is not limited to this and may also be a slope on developed land or a slope on a levee. The work area W is, for example, a steep slope with a maximum gradient of 30 to 50 degrees or more (see FIG. 2), but is not limited to this and may also be a gentler slope.

[0024] The body of the work vehicle 10 is suspended above a working area W on a slope by, for example, two wires R1, R2 supported by fixed objects spaced a predetermined distance apart. The fixed objects are, for example, a pair of piles P1, P2 driven into the ground at a predetermined distance apart at the top or midway of the working area W or a slope near the working area W. In addition to the piles P1, P2, the fixed objects may also be guardrails, trees, or other structures.

[0025] The wires R1 and R2 are ropes, for example, wires made of woven metal wires. The wires R1 and R2 may be metal wires, or may be strings or cords woven from natural materials, synthetic fibers, composite materials, or resin materials, or may be resin-molded ropes. One end of the wire R1 is, for example, loop-shaped and is hooked and supported by a stake P1 fixed to the ground. One end of the wire R2 is, for example, loop-shaped and is hooked and supported by a stake P2 fixed to the ground. A snap hook or other support member for hooking onto the stakes P1 and P2 may be connected to one end of the wires R1 and R2. The other ends of the wires R1 and R2 are connected to reels 22 and 22 (see FIG. 3), which will be described later.

[0026] The piles P1 and P2 are, for example, steel rods made from reinforcing bars or the like. The piles P1 and P2 are, for example, inserted into polyvinyl chloride pipes that have been buried in the ground in advance. The piles P1 and P2 may also be driven directly into the ground. In addition to steel rods, the piles P1 and P2 may be made of any material that can support one end of the wires R1 and R2.

[0027] When the work vehicle 10 begins to be used, the wires R1, R2 are unwound from the reels 22, 22 (see FIG. 3), and one end is hooked to the piles P1, P2. Tension is generated in the wires R1, R2 hooked to the piles P1, P2. With tension generated in the wires R1, R2, the motors 21, 21 (see FIG. 3) are rotated forward or reverse, thereby independently adjusting the amount of winding and unwinding (extension) of the wires R1, R2. As a result, the work vehicle 10 travels along a predetermined travel path in the work area W, using the tension in the wires R1, R2 as a driving source. In other words, the work vehicle 10 is a vehicle whose position is controlled by the winding and unwinding of the wires R1, R2, one end of which is supported by a fixed object. The initial position of the work vehicle 10 is determined based on the lengths of the two wires R1, R2 at the travel start point. In order to measure the initial position of the working vehicle 10, a scale may be marked from one end of the wires R1, R2 up to a predetermined length.

[0028] Control information for the work vehicle 10 is accepted by the operation unit 300. The operation unit 300 accepts operations by the user and transmits control information for driving the work vehicle 10 to the control unit 50 (see FIG. 3) via the communication unit 60 (see FIG. 3). The operation unit 300, for example, communicates wirelessly with the communication unit 60 (see FIG. 3). The operation unit 300 is, for example, a general-purpose mobile terminal device with a communication function, such as a tablet terminal, smartphone, or notebook PC (Personal Computer). Alternatively, the operation unit 300 may be a desktop PC. The operation unit 300 may, for example, be a PC connected to a wired LAN that is connected to the Internet. In this way, the operation unit 300 may be any terminal that is capable of using browser software with a communication function. The operation unit 300 may be configured as a dedicated terminal.

[0029] FIG. 3 is a perspective view showing the configuration of the work vehicle 10. For ease of explanation, the frame portion of the vehicle body provided on the work vehicle 10 is omitted from FIG. 3 and FIG. 4, which will be described later. As shown in FIG. 3, the work vehicle 10 has three wheels T1, T2, and T3 that support the vehicle body for free movement. In the work vehicle 10, for example, one wheel T1 is provided in the center in the width direction on one end side of the wires R1 and R2 (the side closer to the piles P1 and P2), and wheels T2 and T3 are provided at both ends in the width direction on the other end side. In the following description, the wheel T1 side may be referred to as the "front" and the wheels T2 and T3 side may be referred to as the "rear." A mowing blade (not shown) for mowing grass is provided on the underside of the vehicle body. The mowing blade may be, for example, a nylon cord cutter or a metal-free blade.

[0030] As shown in FIG. 3, the work vehicle 10 is equipped with first guide portions 11a, 11b and second guide portions 12a, 12b as components for guiding the wires R1, R2. The first guide portion 11a and the second guide portion 12a are components for guiding the wire R1. The first guide portion 11b and the second guide portion 12b are components for guiding the wire R2. The first guide portion 11a and the second guide portion 12b are provided on one side in the width direction of the work vehicle 10, and the first guide portion 11b and the second guide portion 12a are provided on the other side in the width direction of the work vehicle 10. In the following description, one side in the width direction may be referred to as the "left" and the other side in the width direction as the "right". In the work vehicle 10, the same components are provided on both the left and right sides.

[0031] One end of the wire R1 is hooked onto the stake P1, and the other end is wound around the right reel 22. The wire R1 extends from one end to the other end, passing through the left portion of the first guide portion 11a, the second guide portion 12a, and the right reel 22. The wire R2 has one end hooked onto the stake P2, and the other end is wound around the left reel 22. The wire R2 extends from one end to the other end, passing through the right portion of the first guide portion 11b, the second guide portion 12b, and the left reel 22. The second guide portions 12a and 12b each have a first portion 12x on the front side and a second portion 12y on the rear side. The wire R1 reaches the reel 22 via the right portion of the first portion 12x and the left portion of the second portion 12y of the second guide portion 12a. The wire R2 passes through the left part of the first part 12x and the right part of the second part 12y of the second guide part 12b and reaches the reel 22. Note that the wires R1 and R2 extend while crossing the guiding structure, but this is not limiting and the wires do not have to cross.

[0032] The work vehicle 10 is equipped with two reels 22, 22, two motors 21, 21, and a motor driver 70 (motor drive control mechanism) as a winding section that is provided corresponding to the wires R1, R2 and winds up the wires R1, R2. The right-side reel 22, motor 21, and motor driver 70 are configured to wind up the wire R1. The left-side reel 22, motor 21, and motor driver 70 are configured to wind up the wire R2. The left and right reels 22, 22 and motors 21, 21 have similar functions, so only the left-side reel 22, motor 21, and motor driver 70 (configuration that winds up the wire R2) will be described here.

[0033] The reel 22 rotates with the wire R2 wound around it, thereby unwinding the wire R2. The other end of the wire R2 is wound around the reel 22. The motor 21 is a drive source that rotates the reel 22. The motor driver 70 controls the drive of the motor 21 under the control of the control unit 50, which will be described later. Note that instead of the motor driver 70, a configuration such as a motor controller or a motor control IC (another configuration capable of controlling the drive of the motor 21) may be employed.

[0034] The work vehicle 10 is further equipped with rollers 23 and gas springs 27 (roller-side elastic bodies) as restraining sections that restrain the wires R1 and R2 wound around the reel 22. The right-side roller 23 and gas spring 27 are configured to restrain the wire R1. The left-side roller 23 and gas spring 27 are configured to restrain the wire R2. The left and right rollers 23 and gas springs 27 have similar functions, so only the left-side roller 23 and gas spring 27 (configured to restrain the wire R2) will be described here.

[0035] The roller 23 is configured to rotate and hold down the wire R2 as the wire R2 is unwound as the reel 22 rotates. The provision of the roller 23 prevents the wire R2 from swelling up as it is being unwound. The gas spring 27 is a spring that applies tension to the roller 23, pressing it toward the reel 22. Note that, instead of the gas spring 27, various elastic bodies (other structures that can apply tension to the roller 23, pressing it toward the reel 22) may be used.

[0036] The work vehicle 10 is further equipped with encoders 24, 24 that detect the rotation of the left and right rollers 23, 23, respectively. The encoders 24, 24 may be rotary encoders, for example. The encoders 24, 24 output the detected rotation status of the rollers 23, 23 to the control unit 50.

[0037] The work vehicle 10 is further equipped with gas springs 25, 25 (rope-side elastic bodies) and detection switches 26, 26. The right-side gas spring 25 and detection switch 26 are configured to be associated with wire R1. The left-side gas spring 25 and detection switch 26 are configured to be associated with wire R2. The left and right gas springs 25, 25 and detection switches 26, 26 have similar functions, so only the left-side gas spring 25 and detection switch 26 (configuration associated with wire R2) will be described here.

[0038] The gas spring 25 is a spring that applies tension to the wire R2. FIG. 4 is a diagram illustrating the tension on the wires R1 and R2. FIG. 4(a) shows a state in which tension is applied to the wires R1 and R2. FIG. 4(b) shows a state in which no tension is applied to the wires R1 and R2 and the wires R1 and R2 are loose. As shown in FIG. 4(a), when tension is applied to the wire R2, the gas spring 25 is compressed. On the other hand, as shown in FIG. 4(b), when no tension is applied to the wire R2 and the wire R2 is loose, the gas spring 25 is extended. Note that various elastic bodies (other structures capable of applying tension to the wire R2) may be used instead of the gas spring 25.

[0039] The detection switch 26 is a switch that detects the expansion / contraction state of the gas spring 25, thereby detecting slack in the tension in the wire R2. The detection switch 26 can detect the expansion / contraction state of the gas spring 25 (FIG. 4(b)), thereby detecting slack in the tension in the wire R2. Note that when there is slack, an error occurs in the reading of the encoder 24 described above. The detection switch 26 may be any switch that can detect the expansion / contraction state of the gas spring 25, and may be, for example, a lever switch. The detection switch 26 outputs the detected expansion / contraction state of the gas spring 25 to the control unit 50.

[0040] The work vehicle 10 further includes a control unit 50, a communication unit 60, a drive unit 31, and a power supply unit 40. The communication unit 60 communicates between the control unit 50 and external devices. The communication unit 60 transmits control information from the operation unit 300 to the control unit 50. The drive unit 31 is configured to drive a cutting blade (not shown) for mowing grass in accordance with the control of the control unit 50. The power supply unit 40 is a power source that supplies power to various devices in the work vehicle 10.

[0041] FIG. 5 is a block diagram showing the functions of the control unit 50. The control unit 50 controls the drive unit 31 as part of the mowing control, and also controls the winding unit for the wires R1 and R2. The control unit 50 performs various controls based on control information received from the operation unit 300 via the communication unit 60. The control unit 50 performs detailed control of the winding of the wires R1 and R2. The control unit 50 stores the rotation direction of the motor 21, the winding direction of the wires R1 and R2 on the reel 22, and the rotation direction of the roller 23 detected by the encoder 24 in association with each other. The control unit 50 also stores the rotation amount of the roller 23 detected by the encoder 24 in association with the winding amount of the wires R1 and R1 wound by the reel 22 in association with each other.

[0042] When the detection switch 26 detects slack in the tension of the wire R1 or the wire R2, the control unit 50 may output a control signal to the winding unit, specifically the motor driver 70, so as to wind up the wire R1 or the wire R2 for which slack has been detected. As described above, the rotation direction of the motor 21 and the winding direction of the wires R1 and R2 are associated in advance. Therefore, the control unit 50 can output a control signal to the motor driver 70 so as to wind up the wire R1 or the wire R2 for which slack has been detected. The control signal may include, for example, information indicating the rotation direction of the motor 21 and information specifying the output voltage to the motor 21.

[0043] The control unit 50 may output a control signal to the motor driver 70 so that the wire R1 or wire R2 whose slack has been detected is wound up only when the detection switch 26 detects slack in the wire R1 or wire R2 a predetermined number of times or more within a predetermined time period.

[0044] The control unit 50 estimates the position of the work vehicle 10 based on the rotational state of the roller 23 detected by the encoder 24, and takes the estimation result into consideration and outputs a control signal to the motor driver 70 so that the work vehicle 10 is controlled to a desired position by winding up the wires R1, R2. Such position estimation is realized by associating the amount of rotation of the roller 23 detected by the encoder 24 with the amount of winding up of the wires R1, R1 wound up by the reel 22.

[0045] FIG. 7 is a diagram illustrating a method for estimating the position of the work vehicle 10. FIG. 7(a) shows an example in which the position is estimated appropriately, and FIG. 7(b) shows an example in which the position is not estimated. In FIGS. 7(a) and 7(b), the horizontal axis represents the position L (m) in the width direction of the work area W, and the vertical axis represents the position H (m) in the length direction perpendicular to the width direction of the work area W. Assume now that the initial position of the work vehicle is (L, H) = (0, 0), the initial length of wire R1 is current_a = 0, and the initial length of wire R2 is current_b = 5. When the length of wire R1 is indicated by current_a in FIG. 7(a) and the work vehicle 10 and pile P1 are connected by wire R1, the predicted range of distance is indicated by a dashed circle. When the length of wire R2 is indicated by current_b in FIG. 7(a) and the work vehicle 10 and pile P2 are connected by wire R2, the predicted range of distance is indicated by a solid circle. Now, the intersection of the dashed circle and the solid circle (white circle in FIG. 7( a )) is estimated to be the position of the work vehicle 10 .

[0046] On the other hand, as shown in Figure 7(b), when the dashed circle estimated from the length of wire R1 and the solid circle estimated from the length of wire R2 do not intersect or adjoin (when the point of contact is 0), it is estimated that, for example, wire R1 or wire R2 has broken, and the position of the work vehicle cannot be estimated.

[0047] The control unit 50 may determine the control content based on the control signal output to the motor driver 70 and the rotation state of the roller 23 detected by the encoder 24.

[0048] For example, when the detection switch 26 detects looseness in the wire R1 or R2 in a first state in which the encoder 24 does not detect rotation of the roller 23 despite outputting a control signal to the motor driver 70 to rotate the motor 21 (either forward or reverse), the control unit 50 may determine that the wire R1 or R2 in which looseness is detected may be broken or otherwise damaged, and may issue a notification urging the user to repair the wire. Examples of such a failure include breakage or tangled wires R1 and R2. The control unit 50 may issue the notification to the operation unit 300 via the communication unit 60, for example. In this case, the operator operating the operation unit 300 can be appropriately notified that repair is required.

[0049] The control unit 50 determines that normal processing is possible if no slack is detected by the detection switch 26 in a second state in which the winding direction of the wires R1, R2 corresponding to the rotation direction of the motor 21 instructed by the control signal output to the motor driver 70 and the winding direction of the wires R1, R2 corresponding to the rotation direction of the roller 23 detected by the encoder 24 are the same. Normal processing is processing in which the position of the work vehicle 10 is estimated based on the rotation state of the roller 23 detected by the encoder 24, and a control signal is output to the motor driver 70 taking into account the estimation result so that the work vehicle 10 is controlled to the desired position by winding the wires R1, R2.

[0050] When the detection switch 26 detects slack in the wire R1 or R2 in the second state, the control unit 50 outputs a control signal to the motor driver 70 so that the wire R1 or R2 in which slack has been detected is wound up by the reel 22. Then, when the rotation direction of the roller 23 detected by the encoder 24 is the direction in which the wire R1 or R2 in which slack has been detected is wound up and the slack in the wire R1 or R2 in which slack has been detected is no longer detected, the control unit 50 determines that the slack has been eliminated and that the normal processing is now possible.

[0051] In a third state in which the winding direction of the wires R1 and R2 corresponding to the rotation direction of the motor 21 instructed by the control signal output to the motor driver 70 does not match the winding direction of the wires R1 and R2 corresponding to the rotation direction of the roller 23 detected by the encoder 24, the control unit 50 outputs a control signal to the motor driver 70 so that the corresponding wire R1 or wire R2 is wound. If the rotation direction of the roller 23 detected by the encoder 24 is not the direction in which the corresponding wire R1 or wire R2 is wound, the control unit 50 may determine that repair is necessary and issue a notification urging the user to perform repair. The control unit 50 may issue the notification to the operation unit 300, for example, via the communication unit 60. In this case, the user operating the operation unit 300 can be appropriately notified that repair is necessary.

[0052] Fig. 6 is a block diagram illustrating an example of the hardware configuration of the control unit 50. The control unit 50 is configured with one or more control computers. As shown in Fig. 6, the control unit 50 has a circuit 190. The circuit 190 includes at least one processor 191, a memory 192, a storage 193, an input / output port 194, an input device 195, and a display device 196.

[0053] The storage 193 has a computer-readable storage medium such as a hard disk, etc. The storage 193 stores a program for causing the control unit 50 to execute a method for controlling the work vehicle 10.

[0054] The control method for the work vehicle 10 is, for example, a control method in which the computer (control unit 50) controlling the work vehicle 10 controls the corresponding winding unit so as to wind up the wire R1 or wire R2 in which slack has been detected, based on the detection of slack in tension in the wire R1 or wire R2 by the detection switch 26. The program in this case is a program that causes the computer (control unit 50) controlling the work vehicle 10 to control the corresponding winding unit so as to wind up the wire R1 or wire R2 in which slack has been detected, based on the detection of slack in tension in the wire R1 or wire R2 by the detection switch 26.

[0055] The control method for the work vehicle 10 is, for example, a control method in which the computer (control unit 50) controlling the work vehicle 10 estimates the position of the work vehicle 10 based on the rotational state of the roller 23 detected by the encoder 24, and takes into account the estimation result and outputs a control signal to the motor driver 70 so that the work vehicle 10 is controlled to the desired position by winding up the wires R1 and R2. The program in this case is a program that causes the computer (control unit 50) controlling the work vehicle 10 to estimate the position of the work vehicle 10 based on the rotational state of the roller 23 detected by the encoder 24, and takes into account the estimation result and outputs a control signal to the motor driver 70 so that the work vehicle 10 is controlled to the desired position by winding up the wires R1 and R2.

[0056] The memory 192 temporarily stores the programs loaded from the storage medium of the storage 193 and the results of calculations by the processor 191. The processor 191 configures the above-mentioned functional modules by executing the programs in cooperation with the memory 192. The input / output port 194 inputs and outputs electrical signals between the communication unit 60, the power supply unit 40, the encoder 24, the motor driver 70, the drive unit 31, and the detection switch 26 in response to commands from the processor 191.

[0057] The input device 195 and the display device 196 function as a user interface for the control unit 50. The input device 195 is, for example, a keyboard, and acquires information input by the user. The display device 196 includes, for example, a liquid crystal monitor, and is used to display information to the user. The input device 195 and the display device 196 may be integrated as a so-called touch panel.

[0058] Next, the processing procedures in the work vehicle 10 will be described with reference to Figures 8 to 11. Figure 8 shows the overall processing procedures, Figure 9 shows the fault detection processing procedures in state I (first state), Figure 10 shows the fault detection processing procedures in state II (second state), and Figure 11 shows the fault detection processing procedures in state III (third state).

[0059] 8, when processing of the work vehicle 10 is started, normal processing is first started (step S1). As described above, normal processing is a process in which the position of the work vehicle 10 is estimated based on the rotational state of the roller 23 detected by the encoder 24, and a control signal is output to the motor driver 70 taking into consideration the estimation result so that the work vehicle 10 is controlled to the desired position by winding up the wires R1 and R2.

[0060] Then, various information is acquired in the control unit 50 (step S2). Specifically, the control unit 50 acquires control information received from the operation unit 300 via the communication unit 60, the rotation status of the roller 23 detected by the encoder 24, and information such as slack in the tension of the wires R1 and R2 detected by the detection switch 26.

[0061] Next, the control unit 50 determines whether the current state corresponds to any one of State I (first state), State II (second state), or State III (third state) (step S3). State I (first state) is a state in which the encoder 24 does not detect rotation of the roller 23, even though a control signal for rotating the motor 21 (forward or reverse) is output to the motor driver 70. State II (second state) is a state in which the winding direction of the wires R1 and R2 corresponding to the rotation direction of the motor 21 instructed by the control signal output to the motor driver 70 and the winding direction of the wires R1 and R2 corresponding to the rotation direction of the roller 23 detected by the encoder 24 are identical. State III (third state) is a state in which the winding direction of the wires R1 and R2 corresponding to the rotation direction of the motor 21 instructed by the control signal output to the motor driver 70 and the winding direction of the wires R1 and R2 corresponding to the rotation direction of the roller 23 detected by the encoder 24 are not identical.

[0062] If the state does not fall into any of state I (first state), state II (second state), and state III (third state), the process is repeated from step S1. On the other hand, if the state falls into any of state I (first state), state II (second state), and state III (third state), a fault detection process is performed according to the state (step S4). The fault detection process in each state in step S4 will be described later with reference to FIGS. 9 to 11. After the fault detection process is performed, the value of a counter related to fault detection (described in detail later) is reset (step S5), and the process is repeated from step S1.

[0063] [Fault detection process for State I (first state)] If it is determined in step S3 that the state corresponds to state I (first state), the fault detection process shown in FIG. 9 is carried out in step S4.

[0064] 9, the control unit 50 determines whether loosening of the tension in the wires R1 and R2 is detected by the detection switch 26 (step S121). If loosening is detected in step S121, the control unit 50 notifies the operation unit 300 via, for example, the communication unit 60, urging the operator to repair the malfunction, and the operator repairs the malfunction (step S122).

[0065] On the other hand, if no slack is detected in step S121 (if the roller 23 is not rotating despite the control signal for rotating the motor 21 being output to the motor driver 70 and no slack is detected in the wires R1 and R2), the control unit 50 first stops the rotation of the motor 21 (step S123). The control unit 50 stops the rotation of the motor 21, for example, by ceasing to output the control signal for rotating the motor 21 to the motor driver 70, or by outputting a stop signal for stopping the motor 21 to the motor driver 70. Depending on the type of motor driver 70 and motor 21, stopping the output may cause the motor 21 to become free. If the tension is too strong and the motor 21 rotates and falls, a weaker value in the winding direction that balances the tension may be entered to prevent the motor 21 from falling.

[0066] Next, the control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 in the reverse direction (step S124). Here, reverse rotation means rotation in the opposite direction to the direction in which the motor 21 was rotating before the motor 21 was stopped. The control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 in the reverse direction at a speed slower than normal rotation (for example, slower than the maximum speed during normal rotation) to accommodate failures.

[0067] Next, the control unit 50 determines whether or not the encoder 24 has detected that the roller 23 is rotating in the direction corresponding to the reverse rotation (step S125). If the roller 23 is not rotating in the direction corresponding to the reverse rotation, the control unit 50 notifies the operation unit 300 via, for example, the communication unit 60, to prompt repair of the malfunction, and the malfunction is repaired by an operator (step S122).

[0068] On the other hand, if roller 23 is rotating in a direction corresponding to reverse rotation, control unit 50 outputs a control signal to motor driver 70 to rotate motor 21 in the initial rotation direction (step S126). The initial rotation direction here refers to the direction in which motor 21 was rotating before motor 21 stopped. Control unit 50 outputs a control signal to motor driver 70 to rotate motor 21 in the initial rotation direction at a speed slower than normal rotation to accommodate failures.

[0069] Next, the control unit 50 determines whether or not the encoder 24 has detected that the roller 23 is rotating in a direction corresponding to the initial rotation direction (step S127). If the roller 23 is not rotating in a direction corresponding to the initial rotation direction, the control unit 50 notifies the operation unit 300 via, for example, the communication unit 60, to prompt repair, and the repair is carried out by an operator (step S122).

[0070] On the other hand, if roller 23 is rotating in a direction corresponding to the initial rotation direction, control unit 50 determines that normal processing is possible (step S128).

[0071] [Fault detection process in State II (second state)] If it is determined in step S3 that the state corresponds to state II (second state), the fault detection process shown in FIG. 10 is carried out in step S4.

[0072] 10, the control unit 50 determines whether or not loosening of tension in the wires R1 and R2 has been detected by the detection switch 26 (step S221). If loosening is not detected in step S221, the control unit 50 determines that normal processing is possible (step S230).

[0073] On the other hand, if looseness is detected in step S221, the control unit 50 stops the rotation of the motor 21 (step S222). The control unit 50 stops the rotation of the motor 21, for example, by ceasing to output to the motor driver 70 a control signal that rotates the motor 21, or by outputting to the motor driver 70 a stop signal for stopping the motor 21.

[0074] Next, the control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 in a direction in which the reel 22 winds up the wire R1 or R2 for which slack has been detected (step S223). The control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 at a speed for use in the event of a malfunction, which is slower than normal rotation.

[0075] Next, the control unit 50 determines whether the encoder 24 has detected that the roller 23 is rotating in a direction corresponding to the winding direction (step S224). If the roller 23 is rotating in a direction corresponding to the winding direction, the control unit 50 determines whether the detection switch 26 has detected any slack in the tension of the wires R1 and R2 (step S225). If any slack has been detected, the process is repeated from step S223, and if any slack has not been detected, it is determined that normal processing is possible (the slack has been eliminated) (step S226).

[0076] If roller 23 is not rotating in a direction corresponding to the winding direction, control unit 50 determines, conversely, whether roller 23 is rotating in a direction corresponding to the unwinding direction (step S227). If roller 23 is rotating in a direction corresponding to the unwinding direction, it is determined that the state is State III (third state) in which the unwinding direction corresponding to the rotation direction of motor 21 and the unwinding direction corresponding to the rotation direction of roller 23 do not match each other, and it is determined that the processing of step S321 is to be performed (step S228). If roller 23 is not rotating in either the direction corresponding to the winding direction or the direction corresponding to the unwinding direction (i.e., roller 23 is not rotating), it is determined that the state is State I (first state), and it is determined that the processing of step S121 is to be performed (step S229).

[0077] [Fault detection process for State III (third state)] If it is determined in step S3 that the state corresponds to state III (third state), the fault detection process shown in FIG. 11 is carried out in step S4.

[0078] 11, when the fault detection process for state III (third state) is started, first, the control unit 50 increments the counter value by 1 (step S321). Next, the control unit 50 determines whether the counter value (total value) is equal to or less than a predetermined n (n is a positive integer) (step S322).

[0079] If the counter value is not equal to or less than n, the control unit 50 notifies the operation unit 300 via the communication unit 60, for example, to prompt the operator to repair the fault, and the fault is repaired by the operator (step S327). In this way, by repairing the fault when the counter value is equal to or greater than a predetermined value, an infinite loop of the fault detection process in state III (third state) is avoided.

[0080] On the other hand, if the counter value is equal to or less than n, the control unit 50 stops the rotation of the motor 21 (step S323). The control unit 50 stops the rotation of the motor 21, for example, by stopping the output of a control signal for rotating the motor 21 to the motor driver 70, or by outputting a stop signal for stopping the motor 21 to the motor driver 70.

[0081] Next, the control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 in the direction in which the reel 22 winds the wires R1 and R2 (step S324). The control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 at a speed slower than normal rotation to accommodate failures.

[0082] Next, the control unit 50 determines whether or not the encoder 24 has detected that the roller 23 is rotating in a direction corresponding to the winding direction (step S325). If the roller 23 is rotating in a direction corresponding to the winding direction, it is determined that the state is State II (second state), and the processing of Step S221 is to be performed (step S326). On the other hand, if the roller 23 is not rotating in a direction corresponding to the winding direction, the control unit 50 issues a notification to the operation unit 300, for example, via the communication unit 60, urging the operator to repair the malfunction, and the malfunction is repaired by an operator (step S327).

[0083] Next, the effects of the work vehicle 10 according to this embodiment will be described.

[0084] The work vehicle 10 of this embodiment is a work vehicle whose position is controlled by winding up wires R1, R2, one end of which is supported by a fixed object, and is equipped with a winding up section provided corresponding to the wires R1, R2 and winding up the wires R1, R2, a gas spring 25 that applies tension to the wires R1, R2, a detection switch 26 that detects slack in the tension in the wires R1, R2 by detecting the expansion / contraction state of the gas spring 25, and a control unit 50 that controls the winding up section, and based on the detection switch 26 detecting slack in the tension in the wire R1 or wire R2, the control unit 50 controls the winding up section so that the wire R1 or wire R2 for which slack has been detected is wound up.

[0085] In the work vehicle 10 according to this embodiment, tension is applied to the wires R1 and R2 by the gas spring 25, which effectively prevents the wires R1 and R2 from loosening (i.e., a deterioration in the accuracy of the position control of the work vehicle 10). Furthermore, in the work vehicle 10 according to this embodiment, the detection switch 26 detects the expansion / contraction state of the gas spring 25, thereby detecting looseness in the wires R1 and R2. This makes it possible to properly detect looseness in the wires R1 and R2. Furthermore, in the work vehicle 10, the control unit 50 controls the winding unit to wind up the wires R1 and R2 for which looseness has been detected, thereby properly eliminating looseness in the wires R1 and R2 and improving the accuracy of the position control of the work vehicle 10. As described above, the work vehicle 10 according to this embodiment allows for more accurate position control.

[0086] The winding / unwinding unit includes a reel 22 that rotates with the wires R1, R2 wound around it to unwind the wires R1, R2, a motor 21 that is a drive source for rotating the reel 22, and a motor driver 70 that controls the drive of the motor 21, and the control unit 50 may output a control signal to the motor driver 70 so that the wire R1 or wire R2 for which slack has been detected is wound by the reel 22. By controlling the motor driver 70 in this manner, slack in the wire R1 or wire R2 can be more reliably eliminated.

[0087] The work vehicle 10 may further include a retainer that retains the wires R1, R2 wound around the reel 22. This configuration prevents the wires R1, R2 from swelling up on the reel 22, allowing for more accurate position control of the work vehicle 10.

[0088] The restraining portion may include a roller 23 that rotates as the wires R1, R2 are unwound as the reel 22 rotates and holds down the wires R1, R2, and a gas spring 27 that applies tension to the roller 23, pressing it toward the reel 22. In this way, the gas spring 27 presses the roller 23 toward the reel 22, thereby more reliably preventing the wires R1, R2 from swelling up on the reel 22.

[0089] The work vehicle 10 may further include an encoder 24 that detects the rotation of the roller 23, and the control unit 50 may determine the control content based on the control signal output to the motor driver 70 and the rotational state of the roller 23 detected by the encoder 24. By detecting the rotation of the roller 23, which rotates as the wires R1, R2 are unwound and holds down the wires R1, R2, the amount of unwound wires R1, R2 can be accurately obtained. The control content is determined taking into consideration the control signal and the actual rotational state of the roller 23 (the amount of unwound wires R1, R2), so that the control content can be appropriately determined based on the actual amount of unwound wires R1, R2 in response to a command.

[0090] In the first state in which the control signal for rotating the motor 21 is output to the motor driver 70 but the encoder 24 does not detect rotation of the roller 23, the control unit 50 may issue a notification urging repair if looseness of the wire R1 or the wire R2 is detected. In this way, if the roller 23 is not rotating in a situation in which the roller 23 is expected to be rotating and looseness of the wire R1 or the wire R2 is detected, it is necessary to stop processing and perform repair, but by issuing a notification urging repair as described above, repair can be performed promptly.

[0091] The control unit 50 may determine that normal processing is possible if no slack is detected in the second state in which the winding direction of the wires R1, R2 corresponding to the rotation direction of the motor 21 instructed by the control signal output to the motor driver 70 and the winding direction of the wires R1, R2 corresponding to the rotation direction of the roller 23 detected by the encoder 24 match. In this way, if the expected and actual winding directions of the wires R1, R2 match and no slack is detected, it is believed that no abnormality has occurred, and therefore it is determined that normal processing is possible, allowing smooth control of the work vehicle 10.

[0092] If slack is detected in the second state, the control unit 50 may output a control signal to the motor driver 70 to cause the wire R1 or R2 in which slack has been detected to be wound by the reel 22, and may determine that the slack has been eliminated and normal processing is now possible when the rotation direction of the roller 23 detected by the encoder 24 is the direction in which the wire R1 or R2 is wound and slack is no longer detected. In this way, even if slack has been detected once, it is determined that normal processing is now possible when the slack is eliminated by winding the wire R1 or R2, thereby allowing for a smooth recovery to normal processing after slack detection.

[0093] In a third state in which the winding direction of the wires R1, R2 corresponding to the rotation direction of the motor 21 instructed by the control signal output to the motor driver 70 does not match the winding direction of the wires R1, R2 corresponding to the rotation direction of the roller 23 detected by the encoder 24, the control unit 50 may output a control signal to the motor driver 70 so that the wires R1, R2 are wound by the reel 22, and may issue a notification to prompt repair if the rotation direction of the roller 23 detected by the encoder 24 is not the direction in which the wires R1, R2 are wound. In this way, when the expected winding direction of the wires R1, R2 does not match the actual winding direction of the wires R1, R2, if the control signal is output so that the wires R1, R2 are wound but the rotation direction of the roller 23 is not the direction in which the wires R1, R2 are wound, it is necessary to stop processing and perform repair. However, by issuing the notification to prompt repair as described above, repair can be performed promptly.

[0094] The control unit 50 may control the corresponding unwinding unit so that the wire R1 or R2 in which slack has been detected is wound up only when the detection switch 26 detects slack a predetermined number of times or more within a predetermined time. This makes it possible to prevent the wire R1 or R2 from being wound up in a state in which slack is not required, for example, because the detection switch 26 has only temporarily detected slack. In other words, the switch behavior can be stabilized. [Explanation of symbols]

[0095] 10...Work vehicle, 21...Motor (winding section), 22...Reel (winding section), 23...Roller (holding section), 24...Encoder, 25...Gas spring (rope side elastic body), 26...Detection switch, 27...Gas spring (roller side elastic body, holding section) 50...Control section, 70...Motor driver (motor drive control mechanism, winding section), R1, R1...Wire (rope body).

Claims

1. A work vehicle whose position is controlled by winding up a rope body whose one end is supported by a fixed object, A winding unit provided corresponding to the rope body and winding the rope body; a rope side elastic body that applies tension to the rope body; a detection switch that detects the tension slack in the rope body by detecting the expansion / contraction state of the rope side elastic body; a control unit that performs control related to the winding unit, The control unit A work vehicle that controls the winding unit so that the rope body in which slack is detected is wound up based on the detection switch detecting slack in the tension of the rope body.

2. The winding unit includes a reel that rotates with the rope body wound around it to wind the rope body, a motor that is a drive source that rotates the reel, and a motor drive control mechanism that controls the drive of the motor, The work vehicle according to claim 1 , wherein the control unit outputs a control signal to the motor drive control mechanism so that the rope body in which the slack has been detected is wound by the reel.

3. The work vehicle according to claim 2 , further comprising a holding portion that holds down the rope body wound around the reel.

4. 4. The work vehicle according to claim 3, wherein the holding portion includes a roller that holds down the rope body while rotating in accordance with the winding of the rope body that is wound in accordance with the rotation of the reel, and a roller-side elastic body that applies tension to the roller to press it in the reel direction.

5. further comprising an encoder for detecting rotation of the roller; 5. The work vehicle according to claim 4, wherein the control unit determines control content based on a control signal output to the motor drive control mechanism and a rotation state of the roller detected by the encoder.

6. 6. The work vehicle according to claim 5, wherein the control unit issues a notification urging repair when the loosening is detected in a first state in which rotation of the roller is not detected by the encoder despite outputting a control signal to rotate the motor to the motor drive control mechanism.

7. 6. A work vehicle as described in claim 5, wherein the control unit determines that normal processing is possible if no slack is detected in a second state in which the winding direction of the rope body corresponding to the rotation direction of the motor indicated by the control signal output to the motor drive control mechanism and the winding direction of the rope body corresponding to the rotation direction of the roller detected by the encoder are identical to each other.

8. 8. The work vehicle according to claim 7, wherein, when slack is detected in the second state, the control unit outputs a control signal to the motor drive control mechanism so that the rope body in which slack has been detected is wound by the reel, and when the rotation direction of the roller detected by the encoder is the direction in which the rope body is wound and the slack is no longer detected, the control unit determines that the slack has been eliminated and normal processing is possible.

9. 6. A work vehicle as described in claim 5, wherein in a third state in which the winding direction of the rope body corresponding to the rotation direction of the motor indicated by the control signal output to the motor drive control mechanism and the winding direction of the rope body corresponding to the rotation direction of the roller detected by the encoder do not match, the control unit outputs a control signal to the motor drive control mechanism so that the rope body is wound by the reel, and if the rotation direction of the roller detected by the encoder is not the direction in which the rope body is wound, an alert is issued to prompt repair of the fault.

10. A work vehicle as described in any one of claims 1 to 9, wherein the control unit controls the corresponding winding unit so that winding of the rope body in which slack is detected is carried out only when the slack is detected by the detection switch a predetermined number of times or more within a predetermined time.

11. A computer for controlling a work vehicle includes a winding section for winding and unwinding a rope body having one end supported by a fixed object, a rope side elastic body for applying tension to the rope body, and a detection switch for detecting slack in tension in the rope body by detecting the expansion and contraction state of the rope side elastic body, A control method for a work vehicle, which controls the corresponding winding unit so that winding of the rope body in which slack is detected is carried out based on the detection of slack in the tension of the rope body by the detection switch.

12. A computer for controlling a work vehicle is provided with: a winding section for winding and unwinding a rope body having one end supported by a fixed object; a rope side elastic body for applying tension to the rope body; and a detection switch for detecting slack in tension in the rope body by detecting the expansion and contraction state of the rope side elastic body. A program that controls the corresponding winding unit so that the rope body in which slack is detected is wound up based on the detection of slack in the tension in the rope body by the detection switch.

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