JP7810424B2 - Work vehicle, control method, and program - Google Patents

Description

One aspect of the present invention relates to a work vehicle, a control method, and a program.

Mountainous areas are home to many small farm fields, each with large ridges and lands, making it an important task to reduce the labor and effort required for ridge maintenance. Ridge maintenance is an important task for maintaining ridges and preventing weeds from invading farmland and pests and diseases, but with a shortage of workers and an aging workforce, ridge maintenance may become difficult, 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 required and streamline the work.

Work vehicles for performing tasks such as mowing in relation to levee management are known, such as those described in Patent Documents 1 and 2. Patent Document 1 discloses a work vehicle that uses the tension in a rope body, one end of which is supported by a fixed object, to reel in and unreel the rope body, 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 amount of two rope bodies.

Japanese Patent Application Laid-Open No. 2019-201560 JP 2015-167492 A

In the work vehicle described above, 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 also a risk that the work vehicle will fall outside the designated area.

One aspect of the present invention was made in consideration of the above-mentioned circumstances, and aims to provide a work vehicle, control method, and program that can perform more accurate position control.

A work vehicle according to one aspect of the present invention is a work vehicle whose position is controlled by winding a rope body, one end of which is supported by a fixed object. It includes: a reel that is provided in correspondence with the rope body and rotates while the rope body is wound around it to wind the rope body; a motor that serves as a drive source for rotating the reel; a motor drive control mechanism that controls the drive of the motor; a roller that holds the rope body while rotating as the rope body is wound and wound with the rotation of the reel; an encoder that detects the rotation of the roller; and a control unit that estimates the position of the work vehicle based on the rotational status of the roller detected by the encoder, and outputs a control signal to the motor drive control mechanism taking into account the estimation result so that the work vehicle is controlled to the desired position by winding the rope body.

In a work vehicle according to one aspect of the present invention, the amount of rope extension can be accurately obtained by detecting the rotation of a roller that rotates and holds down the rope as it is extended. The position of the work vehicle is then estimated based on the obtained rotational status of the roller (i.e., the amount of rope extension obtained with high accuracy), and position control of the work vehicle is carried out, allowing for accurate position control of the work vehicle. Furthermore, the roller prevents the rope from swelling up on the reel, allowing for more accurate position control of the work vehicle according to the amount of rope extension.

The work vehicle may further include a roller-side elastic body that applies tension to the roller, pressing it in the reel direction. In this way, the roller-side elastic body presses the roller in the reel direction, more reliably preventing the rope body from swelling up on the reel.

The work vehicle may further include a rope-side elastic body that applies tension to the rope body, and a detection switch that detects slack in the rope body by detecting the expansion/contraction state of the rope-side elastic body. The control unit may output a control signal to the motor drive control mechanism when the detection switch detects slack in the rope body, so as to rewind the rope body for which slack is detected. Applying tension to the rope body by the rope-side elastic body effectively prevents the rope body from slackening (i.e., a deterioration in the accuracy of position control of the work vehicle). Furthermore, the detection switch detects the expansion/contraction state of the rope-side elastic body, so that slack in the rope body can be properly detected. In a work vehicle according to one aspect of the present invention, the control unit controls the reeling unit to rewind the rope body for which slack is detected, thereby properly eliminating slack in the rope body and improving the accuracy of position control of the work vehicle.

The control unit may determine the control content based on the control signal output to the motor drive control mechanism and the roller rotation status detected by the encoder. By determining the control content taking into account the control signal and the actual roller rotation status (amount of rope winding), the control content can be appropriately determined based on the actual amount of rope winding in response to the command.

In the first state, in which the encoder does not detect roller rotation despite outputting a control signal to the motor drive control mechanism to rotate the motor, the control unit may issue a notification urging repair if slack is detected. In this way, if the roller is not rotating in a situation where it is expected to be rotating and slack in the rope body is detected, processing would need to be stopped and repairs performed. However, by issuing a notification urging repair as described above, repairs can be performed promptly.

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 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 the same. In this way, if the expected and actual winding directions of the rope body are the same and no slack is detected, it is assumed that no abnormality has occurred, and therefore it is determined that normal processing is possible, allowing for smooth control of the work vehicle.

If 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 reeled in 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 reeled in and slack is no longer detected. In this way, even if slack has been detected once, it can be determined that normal processing is now possible when the slack is eliminated by reeling in the rope body, allowing for a smooth return to normal processing after slack detection.

In a third state in which the winding direction of the rope body corresponding to the motor rotation direction indicated by the control signal output to the motor drive control mechanism does not match the winding direction of the rope body corresponding to the roller rotation direction 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 roller rotation direction detected by the encoder is not the direction in which the rope body is wound, an alert may be issued to prompt repair. In this way, when the expected and actual winding directions of the rope body do not match, if a control signal is output to wind the rope body but the roller rotation direction is not the direction in which the rope body is wound, processing must be stopped and repairs performed. However, by issuing an alert to prompt repair as described above, repairs can be performed promptly.

The control unit may control the corresponding unwinding unit so that the rope body in which slack has been detected is wound up only if 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 up when, for example, slack has only been detected temporarily by the switch and winding up of the rope body is not necessary. In other words, it is possible to stabilize the switch behavior.

In one aspect of the present invention, a work vehicle control method includes a reel provided for each rope body, one end of which is supported by a fixed object, and which rotates with the rope body wound around it to unwind the rope body; a motor that serves as a drive source for rotating the reel; a motor drive control mechanism that controls the motor; a roller that rotates as the reel rotates to hold down the rope body wound around the reel; and an encoder that detects the rotation of the roller. A computer controls the work vehicle, estimating the position of the work vehicle based on the rotational state of the roller detected by the encoder, and, taking the estimation result into consideration, outputs a control signal to the motor drive control mechanism so that the work vehicle is controlled to the desired position by unwinding the rope body. This control method enables more accurate position control of the work vehicle.

One aspect of the present invention is a program that causes a computer controlling a work vehicle equipped with reels provided in correspondence with rope bodies, one end of which is supported on a fixed object, that rotate with the rope body wound around them to unwind the rope body, a motor that serves as a drive source for rotating the reel, a motor drive control mechanism that controls the motor, a roller that rotates in conjunction with the rotation of the reel to hold down the rope body wound around the reel, and an encoder that detects the rotation of the roller to estimate the position of the work vehicle based on the rotational status of the roller detected by the encoder, and, taking into account the estimation result, output a control signal to the motor drive control mechanism so that the work vehicle is controlled to the desired position by unwinding the rope body. Such a program enables more accurate position control of the work vehicle.

One aspect of the present invention provides a work vehicle, control method, and program that can perform more accurate position control.

1 is a schematic diagram showing an image of a work performed by a work vehicle according to an embodiment of the present invention; 1 is a schematic diagram showing an image of a work performed by a work vehicle according to an embodiment of the present invention; FIG. 1 is a perspective view showing a configuration of a work vehicle. 10A and 10B are diagrams illustrating tension on a wire. FIG. 2 is a block diagram showing the functions of a control unit. FIG. 2 is a block diagram illustrating a hardware configuration of a control unit. FIG. 1 is a diagram illustrating a position estimation technique. 10 is a flowchart showing a processing procedure in a work vehicle. 10 is a flowchart showing a processing procedure in a work vehicle. 10 is a flowchart showing a processing procedure in a work vehicle. 10 is a flowchart showing a processing procedure in a work vehicle.

Embodiments of a work vehicle, a work vehicle control method, and a program will be described below with reference to the drawings. In the description, identical elements or elements with identical functions will be designated by the same reference numerals, and duplicate descriptions will be omitted.

1 and 2 are schematic diagrams showing an image of the work 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 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 the slope of a developed land or the slope of 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.

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

The wires R1 and R2 are ropes, such as wires made of woven metal wires. In addition to metal wires, the wires R1 and R2 may also be cords or ropes made of woven natural materials, synthetic fibers, composite materials, or resin materials, or ropes molded from resin. One end of the wire R1 is, for example, loop-shaped and is supported by being hooked onto a stake P1 fixed to the ground. One end of the wire R2 is, for example, loop-shaped and is supported by being hooked onto 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 Figure 3), which will be described later.

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

When the work vehicle 10 begins to be used, the wires R1 and R2 are unwound from the reels 22 and 22 (see Figure 3), and one end is hooked to the stakes P1 and P2. Tension is generated in the wires R1 and R2 hooked to the stakes P1 and P2. With tension generated in the wires R1 and R2, the motors 21 and 21 (see Figure 3) are rotated forward or backward, independently adjusting the amount of winding and unwinding (stretching) of the wires R1 and 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 and 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 and R2, one end of which is supported by a fixed object. The initial position of the work vehicle 10 is determined based on the length of the two wires R1 and R2 at the start of travel. In addition, scales may be marked from one end of the wires R1 and R2 up to a predetermined length in order to measure the initial position of the work vehicle 10.

Control information for the work vehicle 10 is received by the operation unit 300. The operation unit 300 receives user operations 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 communication capabilities, 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 connects to the Internet. In this way, the operation unit 300 may be any terminal that can use browser software with communication capabilities. The operation unit 300 may also be configured as a dedicated terminal.

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

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." The work vehicle 10 has the same components on both the left and right sides.

One end of the wire R1 is hooked onto the stake P1, and the other end is wound around the right-side reel 22. The wire R1 extends from one end to the other, passing through the left side of the first guide portion 11a, the second guide portion 12a, and the right-side reel 22. The wire R2 is hooked onto the stake P2, and the other end is wound around the left-side reel 22. The wire R2 extends from one end to the other, passing through the right side of the first guide portion 11b, the second guide portion 12b, and the left-side 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 side of the first portion 12x and the left side of the second portion 12y of the second guide portion 12a. The wire R2 passes through the left side of the first portion 12x and the right side of the second portion 12y of the second guide portion 12b before reaching the reel 22. Note that the wires R1 and R2 extend while crossing the guiding structure, but this is not limited to this and they do not have to cross.

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 corresponds to the wires R1, R2 and winds the wires R1, R2. The right-side reel 22, motor 21, and motor driver 70 are configured to wind the wire R1. The left-side reel 22, motor 21, and motor driver 70 are configured to wind the wire R2. Because the left and right reels 22, 22 and motors 21, 21 have similar functions, only the left-side reel 22, motor 21, and motor driver 70 (configuration that winds the wire R2) will be described here.

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 in accordance with the control of the control unit 50, which will be described later. Note that instead of the motor driver 70, a motor controller, a motor control IC, or other configuration (other configuration capable of controlling the drive of the motor 21) may be used.

The work vehicle 10 further includes rollers 23 and gas springs 27 (roller-side elastic bodies) as restraining sections for restraining 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.

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 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.

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.

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 connected to wire R1. The left-side gas spring 25 and detection switch 26 are configured to be connected to 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 connected to wire R2) will be described here.

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

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 slack in the tension in the wire R2 by detecting the expanded state of the gas spring 25 (Figure 4(b)). Note that when there is slack, an error will be introduced into 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, such as a lever switch. The detection switch 26 outputs the detected expansion/contraction state of the gas spring 25 to the control unit 50.

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 mowing 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.

Figure 5 is a block diagram showing the functions of the control unit 50. The control unit 50 controls the drive unit 31 for 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 for winding the wires R1 and R2 is described in detail below. 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, all associated with each other. The control unit 50 also stores the amount of rotation of the roller 23 detected by the encoder 24 and the amount of winding of the wires R1 and R1 wound by the reel 22, all associated with each other.

When the detection switch 26 detects a slack in the tension of the wire R1 or wire R2, the control unit 50 may output a control signal to the winding unit, specifically the motor driver 70, so that the wire R1 or wire R2 for which the slack has been detected is wound up. 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 that the wire R1 or wire R2 for which the slack has been detected is wound up. 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.

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

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, taking the estimation result into consideration, outputs a control signal to the motor driver 70 so that the work vehicle 10 is controlled to the desired position by winding the wires R1 and R2. This position estimation is achieved by correlating the amount of rotation of the roller 23 detected by the encoder 24 with the amount of winding of the wires R1 and R1 wound by the reel 22.

Figure 7 is a diagram explaining a method for estimating the position of the work vehicle 10. Figure 7(a) shows an example in which the position is estimated appropriately, and Figure 7(b) shows an example in which the position is not estimated. In Figures 7(a) and (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. Now, assume 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 Figure 7(a) and the work vehicle 10 and pile P1 are connected by wire R1, the predicted range of distance is shown by a dashed circle. Furthermore, the length of wire R2 is shown as current_b in Figure 7(a), and when the work vehicle 10 and pile P2 are connected by wire R2, the predicted distance range is shown by a solid circle. The intersection of the dashed circle and the solid circle (white circle in Figure 7(a)) is now estimated to be the position of the work vehicle 10.

On the other hand, as shown in Figure 7(b), if 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 (if the number of tangency points 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.

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

For example, if 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 warning to prompt repair. Examples of such a warning include breakage or tangled wires R1, R2. The control unit 50 may issue the warning 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 informed of the need for repair.

In the second 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 the same, if no slack is detected by the detection switch 26, the control unit 50 determines that normal processing is possible. Normal processing is a process in which the position of the work vehicle 10 is estimated based on the rotation status 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 and R2.

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. The control unit 50 then determines 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 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.

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

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

Storage 193 has a computer-readable storage medium, such as a hard disk. Storage 193 stores a program that causes control unit 50 to execute a control method for work vehicle 10.

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 that the wire R1 or wire R2 in which slack is detected is wound up based on the detection switch 26 detecting slack in the tension in the wire R1 or wire R2. 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 that the wire R1 or wire R2 in which slack is detected is wound up based on the detection switch 26 detecting slack in the tension in the wire R1 or wire R2.

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 the estimation result into account 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 the estimation result into account 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.

Memory 192 temporarily stores programs loaded from the storage medium of storage 193 and the results of calculations performed by processor 191. Processor 191 executes the programs in cooperation with memory 192 to configure the functional modules described above. Input/output port 194 inputs and outputs electrical signals between communication unit 60, power supply unit 40, encoder 24, motor driver 70, drive unit 31, and detection switch 26 in response to commands from processor 191.

The input device 195 and 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, an LCD monitor, and is used to display information to the user. The input device 195 and display device 196 may be integrated as a so-called touch panel.

Next, the processing procedures in the work vehicle 10 will be explained 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).

As shown in Figure 8, when processing of the work vehicle 10 begins, normal processing begins first (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 account the estimation result so that the work vehicle 10 is controlled to the desired position by winding up the wires R1 and R2.

Then, the control unit 50 acquires various information (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.

Next, the control unit 50 determines whether the current state is 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 (either 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.

If the current state is not State I (first state), State II (second state), or State III (third state), processing begins again from step S1. On the other hand, if the current state is State I (first state), State II (second state), or State III (third state), fault detection processing is performed according to the current state (step S4). The fault detection processing for each state in step S4 will be described later with reference to Figures 9 to 11. After the fault detection processing is performed, the value of the fault detection counter (described in detail below) is reset (step S5), and processing begins again from step S1.

[Fault detection process in 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.

As shown in FIG. 9, the control unit 50 determines whether the detection switch 26 has detected loose tension in the wires R1 and R2 (step S121). If looseness is detected in step S121, the control unit 50 notifies the operation unit 300, for example via the communication unit 60, to prompt repair, and the worker then repairs the malfunction (step S122).

On the other hand, if no slack is detected in step S121 (a control signal to rotate the motor 21 is output to the motor driver 70, but the roller 23 is not rotating, 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 to rotate the motor 21 to the motor driver 70, or by outputting a stop signal to stop 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 motor 21 rotates and falls when tension is too strong, a weaker value in the winding direction that balances the tension may be entered to prevent it from falling.

Next, the control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 in reverse (step S124). In this case, reverse rotation refers to rotation in the opposite direction to the direction in which the motor 21 was rotating before it was stopped. The control unit 50 outputs a control signal to the motor driver 70 to rotate the motor 21 in reverse at a speed that is slower than normal rotation (for example, slower than the maximum speed during normal rotation) to accommodate failures.

The control unit 50 then determines whether the encoder 24 detects 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, for example via the communication unit 60, to prompt repair, and the worker then repairs the malfunction (step S122).

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

The control unit 50 then determines whether the encoder 24 detects 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, for example via the communication unit 60, to prompt repair, and the worker then repairs the malfunction (step S122).

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

[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.

As shown in FIG. 10, the control unit 50 determines whether the detection switch 26 has detected loose tension in the wires R1 and R2 (step S221). If looseness is not detected in step S221, the control unit 50 determines that normal processing is possible (step S230).

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 that stops the motor 21.

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 up the wire R1 or wire 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 slower than normal rotation to accommodate a malfunction.

Next, the control unit 50 determines whether the encoder 24 detects 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 detects any slack in the tension of the wires R1 and R2 (step S225). If slack is detected, the process is repeated from step S223; if no slack is detected, it is determined that normal processing is possible (the slack has been eliminated) (step S226).

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

[Fault detection process in 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.

As shown in FIG. 11, when the fault detection process for State III (third state) is initiated, the control unit 50 first 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 value n (n is a positive integer) (step S322).

If the counter value is not equal to or less than n, 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 fault, and the fault is repaired by the operator (step S327). In this way, by performing repairs 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.

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 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 that stops the motor 21.

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 a failure.

The control unit 50 then determines whether 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 determines that the state is State II (second state) and determines that 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 notifies the operation unit 300, for example via the communication unit 60, to prompt repair, and the repair is then performed by an operator (step S327).

Next, we will explain the effects of the work vehicle 10 according to this embodiment.

The work vehicle 10 according to this embodiment is a work vehicle whose position is controlled by winding wires R1, R2, one end of which is supported by a fixed object. It is equipped with a winding unit provided corresponding to the wires R1, R2 and winding 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 unit. When the detection switch 26 detects slack in the tension in the wire R1 or wire R2, the control unit 50 controls the winding unit to wind up the wire R1 or wire R2 for which slack has been detected.

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 allows for appropriate detection of 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 appropriately 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 enables more accurate position control.

The winding/unwinding unit includes a reel 22 that rotates with the wires R1 and R2 wound around it to unwind the wires R1 and R2, a motor 21 that is the drive source for rotating the reel 22, and a motor driver 70 that controls the drive of the motor 21. The control unit 50 may output a control signal to the motor driver 70 so that the wire R1 or wire R2 in 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.

The work vehicle 10 may further include a retaining portion 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.

The holding down portion may include a roller 23 that rotates as the wires R1, R2 are unwound as the reel 22 rotates, while holding 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.

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 rotation status 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 wound and holds them down, the amount of winding of the wires R1, R2 can be accurately obtained. The control content is then determined taking into consideration the control signal and the actual rotation status of the roller 23 (the amount of winding of the wires R1, R2), so that the control content can be appropriately determined based on the actual amount of winding of the wires R1, R2 in response to the command.

In the 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, the control unit 50 may issue a notification urging repair if loose wire R1 or R2 is detected. In this way, if the roller 23 is not rotating in a situation in which it is assumed that the roller 23 is rotating, and loose wire R1 or R2 is detected, it would be necessary to stop processing and perform repairs. However, by issuing a notification urging repairs as described above, repairs can be performed promptly.

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 assumed that no abnormality has occurred, and therefore it is determined that normal processing is possible, allowing smooth control of the work vehicle 10.

If slack is detected in the second state, the control unit 50 may output a control signal to the motor driver 70 so that the wire R1 or wire R2 in which slack has been detected is 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 wire R2 is wound and slack is no longer detected. In this way, even if slack has been detected once, it can be determined that normal processing is now possible when the slack is eliminated by winding the wire R1 or wire R2, allowing for a smooth return to normal processing after slack detection.

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

The control unit 50 may control the corresponding unwinding unit so that the wire R1 or R2 in which slack is detected is wound up only if the detection switch 26 detects slack a predetermined number of times or more within a predetermined time. This makes it possible to prevent the winding of the wire R1 or R2 from being performed when, for example, slack is only temporarily detected by the detection switch 26 and winding of the wire R1 or R2 is not necessary. In other words, the switch behavior can be stabilized.

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

Claims (11)

A work vehicle whose position is controlled by winding up a rope body whose one end is supported by a fixed object,
a reel provided corresponding to the rope body, which rotates with the rope body wound around it to unwind the rope body;
a motor that is a drive source for rotating the reel;
a motor drive control mechanism for controlling the drive of the motor;
a roller that rotates and holds down the rope body as the rope body is unwound with the rotation of the reel;
an encoder for detecting rotation of the roller;
a control unit that estimates the position of the work vehicle based on the rotational status of the roller detected by the encoder, and that outputs a control signal to the motor drive control mechanism taking into account the estimation result so that the work vehicle is controlled to the desired position by winding up the rope body. The work vehicle of claim 1, further comprising a roller-side elastic body that applies tension to the roller in the reel direction. a rope side elastic body that applies tension to the rope body;
Further provided is a detection switch that detects the tension slack in the rope body by detecting the expansion and contraction state of the rope side elastic body,
2. The work vehicle according to claim 1, wherein the control unit outputs a control signal to the motor drive control mechanism when the detection switch detects slack in tension in the rope body so that the rope body in which the slack is detected is wound up. A work vehicle as described in claim 3, wherein the control unit determines the control content based on the control signal output to the motor drive control mechanism and the rotation status of the roller detected by the encoder. A work vehicle as described in claim 4, wherein the control unit issues a notification urging repair when 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. A work vehicle as described in claim 4, 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. A work vehicle as described in claim 6, 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 is 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. A work vehicle as described in claim 4, 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 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 issues a notification urging repair if the rotation direction of the roller detected by the encoder is not the direction in which the rope body is wound. A work vehicle as described in claim 3, 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 up only if the detection switch detects the slack a predetermined number of times or more within a predetermined time. A computer for controlling a work vehicle includes: a reel provided in correspondence with each rope body, one end of which is supported by a fixed object, and which rotates with the rope body wound around it to unwind the rope body; a motor which is a drive source for rotating the reel; a motor drive control mechanism which controls the motor; a roller which rotates in accordance with the rotation of the reel to hold down the rope body wound around the reel; and an encoder which detects the rotation of the roller;
A method for controlling a work vehicle, which estimates the position of the work vehicle based on the rotational status of the roller detected by the encoder, and taking into account the estimation result, outputs a control signal to the motor drive control mechanism so that the work vehicle is controlled to the desired position by winding up the rope body. A computer for controlling a work vehicle includes: a reel provided in correspondence with each rope body, one end of which is supported by a fixed object, and which rotates with the rope body wound around it to unwind the rope body; a motor which is a drive source for rotating the reel; a motor drive control mechanism which controls the motor; a roller which rotates in accordance with the rotation of the reel to hold down the rope body wound around the reel; and an encoder which detects the rotation of the roller.
A program that executes the following steps: estimating the position of the work vehicle based on the rotational status of the roller detected by the encoder; and, taking into account the estimation result, outputting a control signal to the motor drive control mechanism so that the work vehicle is controlled to the desired position by winding up the rope body.