Transport vehicle

Abstract

To detect an overspeed of a conveyance vehicle with a simple configuration.SOLUTION: A conveyance vehicle 100 travels with wheels 120 mounted to a body 110. The conveyance vehicle 100 includes: a body to be detected 130 mounted so as to rotate together with rotation of the wheels 120 and having a first part 131 longer than a half circumference and a second part 132 being the other part around a rotation axis 125; a first sensor 141 and a second sensor 142 arranged at an inversion position with the rotation shaft 125 as reference to be able to detect the first part 131 and the second part 132; and a determination device 150 having a speed determination part 151 for determining an overspeed on the basis of the fact that a time from a change in a detection result by the first sensor 141 to a change in a detection result of the second sensor 142 is a time threshold or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a transport vehicle for transporting luggage. [Background technology]

[0002] In transport vehicles that carry cargo and travel on a floor, the speed of the transport vehicle may be monitored using a speed monitoring unit separate from the sensor equipped on the drive source in order to prevent runaway caused by a malfunction of the encoder of the motor that drives the transport vehicle.

[0003] For example, Patent Document 1 describes a technology that accurately detects the speed state by providing a roller that rotates in contact with the track on which the transport vehicle travels, and using a sensor to detect the rotation of a shielding plate that rotates together with the roller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-277416 Summary of the Invention [Problem to be solved by the invention]

[0005] However, providing rollers that contact the travel path complicates the structure of the transport vehicle. Furthermore, when detecting the speed of the transport vehicle using a shielding plate with multiple through-holes circumferentially centered on the roller's rotation axis, even a slight vibration of the stopped transport vehicle can generate pulses that alternate between blocking and passing light. In this case, the transport vehicle may malfunction, forcing it to shut down due to a false detection of abnormal operation even when the transport vehicle is stopped normally.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a transport vehicle that can detect excessive speed of the transport vehicle with a simple structure without using rollers or the like to detect the speed state, and that can suppress the occurrence of false detection even if the transport vehicle vibrates while stopped. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, one aspect of the present invention is a transport vehicle that runs on wheels attached to a main body, and is equipped with a detectable object having a first part and a second part that rotate together with the rotation of the wheels, a first sensor and a second sensor that are attached to the main body so that there is a timing when the rotating parts can be detected simultaneously but the second part cannot be detected simultaneously, and a judgment device that has a speed judgment unit that judges that the speed is exceeded based on the time from when the detection result by the first sensor changes to when the detection result by the second sensor changes being less than a time threshold. [Effects of the Invention]

[0008] According to the present invention, it is possible to detect excessive speed of a transport vehicle with a simple structure, and to suppress erroneous detection of speed due to vibration of the transport vehicle when stopped. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing the inside of the transport vehicle in a see-through state. [Figure 2] FIG. 2 is a perspective view showing the vicinity of the object to be detected. [Figure 3] FIG. [Figure 4] FIG. 2 is a block diagram showing a functional configuration of a determination device. [Figure 5] 10 is a timing chart showing a state of speeding determination. [Figure 6] 10 is a timing chart showing a state of determining a sensor abnormality. [Figure 7] FIG. 10 is a perspective view showing another example 1 of a detection object and a sensor. [Figure 8] FIG. 10 is a perspective view showing another example 2 of the detection object and the sensor. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a transport vehicle according to the present invention will be described with reference to the drawings. Note that the following embodiments are presented as examples to explain the present invention and are not intended to limit the present invention. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, mathematical formulas, the content of each step in a method, and the order of each step shown in the following embodiments are merely examples and may include content not described below. Furthermore, while geometric expressions such as parallel and orthogonal may be used, these expressions do not indicate mathematical precision and include substantially acceptable errors, deviations, and the like. Furthermore, expressions such as simultaneous and identical also include substantially acceptable ranges.

[0011] Furthermore, the drawings are schematic diagrams in which emphasis, omission, or adjustment of proportions is appropriately made in order to explain the present invention, and the shapes, positional relationships, and proportions may differ from the actual shapes, positional relationships, and proportions.

[0012] In addition, in the following, multiple inventions may be collectively described as one embodiment, and some of the contents described below may be described as optional components related to the present invention.

[0013] 1 is a perspective view showing the interior of a transport vehicle 100 in a see-through state. As shown in the figure, the transport vehicle 100 is a traveling vehicle that can hold a load on a main body 110 and can travel using wheels 120 attached to the main body 110, and is equipped with a detectable object 130, a first sensor 141, a second sensor 142, and a determination device 150.

[0014] In this embodiment, the transport vehicle 100 is equipped with two wheels 120 that can be rotated independently and auxiliary wheels 121 such as casters. Each wheel 120 is connected to a drive unit 122 including a reducer and the like via a motor and an axle 123. The rotation speed and rotation direction of each wheel 120 are independently controlled by a control unit 124 equipped in the transport vehicle 100, thereby enabling the transport vehicle 100 to move forward, backward, curve, pivot, and so on. Note that the type of transport vehicle 100 is not limited to the above, and it may be equipped with four wheels 120, for example. Furthermore, the transport vehicle 100 may be a tracked vehicle as well as a non-tracked vehicle.

[0015] Fig. 2 is a perspective view showing the vicinity of the detection object 130. Fig. 3 is a front view showing the vicinity of the detection object 130. As shown in these figures, the detection object 130 is attached so as to rotate together with the rotation of the wheel 120, and has a first portion 131 that is longer than half the circumference of a predetermined circle around the rotation axis 125 of the wheel 120, and a second portion 132 that is the portion of the predetermined circle other than the first portion 131. In the case of this embodiment, the detection object 130 has a cylindrical attachment portion 133 for fixing to the pierced axle 123.

[0016] First part 131 is a part that is detected by first sensor 141 and second sensor 142 (hereinafter, first sensor 141 and second sensor 142 may be collectively referred to as sensors in some cases), as distinguished from second part 132. The shape of first part 131 is not particularly limited as long as it is longer than half the circumference around rotation axis 125. In the present embodiment, first part 131 has a cylindrical shape that is arranged coaxially with rotation axis 125, and is the remaining part with a portion shorter than half the circumference around rotation axis 125 cut out. In other words, when detection object 130 is rotated once around rotation axis 125, first part 131 is a part that continues to be detected by first sensor 141 and second sensor 142 for longer than half the circumference.

[0017] The length of first portion 131 is not particularly limited as long as it is longer than half the circumference around rotation axis 125. For example, when wheel 120 is stopped, that is, when control device 124 controls wheel 120 to stop, and both first sensor 141 and second sensor 142 simultaneously detect first portion 131 as shown in FIG. 3 , a length sufficient to prevent the state in which only one of first sensor 141 and second sensor 142 detects first portion 131 from changing even when wheel 120 vibrates due to vibrations applied to transport vehicle 100 from an external source. For example, the length of first portion 131 is set taking into consideration the oscillation of wheel 120 due to backlash of a gear coupled to wheel 120. Specifically, first portion 131 preferably occupies an angle range selected from 190 degrees or more and 200 degrees or less around rotation axis 125.

[0018] Second portion 132 is a portion that is detected by the sensor as distinct from first portion 131. The shape of second portion 132 is not particularly limited as long as it traces the same circular path as first portion 131 and is shorter than half the circumference around rotation axis 125. In the present embodiment, second portion 132 is a cut-out remaining portion of a cylinder that includes first portion 131 and is disposed coaxially with rotation axis 125. In other words, second portion 132 is a space, and when detectable object 130 is rotated once around rotation axis 125, second portion 132 is a space (portion) that is detected by first sensor 141 and second sensor 142 as being shorter than half the circumference, and first sensor 141 and second sensor 142 detect second portion 132 by detecting that nothing is present.

[0019] The length of second portion 132 is not particularly limited as long as it is shorter than half the circumference around rotation axis 125. Specifically, the length is such that only one of first sensor 141 and second sensor 142 can detect second portion 132. Specifically, second portion 132 preferably occupies an angular range of less than 170 degrees around rotation axis 125. Furthermore, first portion 131 and second portion 132 are arranged on the same circumference.

[0020] The first sensor 141 and the second sensor 142 may be disposed at a timing when they can simultaneously detect the first part 131 and at a position where they cannot simultaneously detect the second part 132. In this embodiment, the first sensor 141 and the second sensor 142 are attached to the main body 110 at inverted positions with respect to the rotation axis 125 of the wheel 120, i.e., at a 180-degree positional relationship centered on the rotation axis 125, and are sensors that can alternately detect the rotating first part 131 and second part 132. The type of sensor is not particularly limited as long as it can distinguishably detect the first part 131 and the second part 132 of the detectable object 130, and is selected corresponding to the type of the detectable object 130. Note that the type of the detectable object 130 may also be selected corresponding to the type of sensor. Examples of sensors include a transmission-type photoelectric sensor, a reflective-type photoelectric sensor, a magnetic sensor, and a proximity sensor.

[0021] In this embodiment, the sensor is a transmission-type photoelectric sensor, and the light-emitting section and the light-receiving section are arranged across the passage area of ​​first section 131, which rotates around rotation axis 125. The sensors are also arranged so that the optical axis of first sensor 141 and the optical axis of second sensor 142 are on a straight line passing through rotation axis 125. The sensor outputs a signal indicating that first section 131 is being detected when no light reaches the light-receiving section, and outputs a signal indicating that second section 132 is being detected when the light-receiving section reacts to the light that has reached it.

[0022] 4 is a block diagram showing the functional configuration of the determination device 150. The determination device 150 is a device that determines whether the vehicle is speeding based on the detection results of the object 130 by the first sensor 141 and the second sensor 142. The determination device 150 includes a processor, and includes a speed determination unit 151 as a processing unit that is realized by causing the processor to execute a program. In this embodiment, the determination device 150 includes an abnormality determination unit 152, a change detection unit 153, and an off-delay unit 154.

[0023] The type of the determination device 150 is not particularly limited, but in this embodiment, a PLC (Programmable Logic Controller) is used as the determination device 150. The determination device 150 determines whether the vehicle is speeding or not, whether there are abnormalities in the first sensor 141 and the second sensor 142, whether to make an emergency stop of the transported vehicle 100 based on a signal from a safety button, and whether the transported vehicle 100 should take evasive action or stop based on a signal from an obstacle sensor.

[0024] The speed determination unit 151 determines that the vehicle is speeding when the time from the change in the detection result by the first sensor 141 to the change in the detection result by the second sensor 142 is equal to or less than a time threshold. The change in the detection result means the point in time when the sensor changes from detecting the first part 131 to detecting the second part 132, or the point in time when the sensor changes from detecting the second part 132 to detecting the first part 131.

[0025] In this embodiment, if the time from the point in time when first sensor 141 changes from detecting second portion 132 to detecting first portion 131 to the point in time when second sensor 142 changes from detecting second portion 132 to detecting first portion 131 is equal to or less than the time threshold, speed determination unit 151 determines that speeding is occurring, and outputs an overspeeding signal indicating speeding to control device 124. Speed ​​determination unit 151 also determines that speeding is occurring if the time from the point in time when second sensor 142 changes from detecting second portion 132 to detecting first portion 131 to the point in time when first sensor 141 changes from detecting second portion 132 to detecting first portion 131 is equal to or less than the time threshold, and outputs an overspeeding signal indicating speeding to control device 124. This allows speed determination to be performed twice per rotation of wheel 120, making it possible to determine speeding early. Although speeding is determined based on the time point at which the detection of the second part 132 changes to the detection of the first part 131, speeding may also be determined based on the time point at which the detection of the first part 131 changes to the detection of the second part 132.

[0026] In this embodiment, the change detection unit 153 detects a change from detecting the second portion 132 of the sensor to detecting the first portion 131 (or vice versa). Specifically, as shown in the timing chart of FIG. 5, when the first sensor 141 changes from detecting the second portion 132 to detecting the first portion 131, the change detection unit 153 outputs a first change pulse corresponding to the first sensor 141 (stage (b) of FIG. 5). Furthermore, when the second sensor 142 changes from detecting the second portion 132 to detecting the first portion 131, the change detection unit 153 outputs a second change pulse corresponding to the second sensor 142 (stage (b) of FIG. 5).

[0027] Speed ​​determination unit 151 determines whether or not the speed is excessive based on whether the time from the change in the detection result by first sensor 141 to the change in the detection result by second sensor 142 is equal to or less than a time threshold, but the method for measuring time is not limited thereto. For example, a timer may be started from the time when the detection result by first sensor 141 changes, and the time until the change in the detection result by second sensor 142 is acquired by the timer and compared with the time threshold. In this embodiment, off-delay unit 154 time-extends the pulse generated by change detection unit 153 in accordance with the time threshold (see row (c) in FIG. 5). If a change detection pulse from one sensor is generated while the off-delay signal corresponding to the other sensor is on, speed determination unit 151 outputs an overspeed signal (row (d) in FIG. 5).

[0028] The abnormality determination unit 152 determines a sensor abnormality based on the detection of the second part 132 of the detection target 130 by both the first sensor 141 and the second sensor 142. Specifically, as shown in Fig. 6, when the abnormality determination unit 152 receives a signal indicating that the first sensor 141 is detecting the second part 132 and then receives a signal indicating that the second sensor 142 is detecting the second part 132, the abnormality determination unit 152 outputs an abnormality signal indicating that an abnormality such as a breakdown or disconnection has occurred in at least one of the first sensor 141 and the second sensor 142.

[0029] According to the transport vehicle 100 of the above embodiment, it is possible to detect excessive rotational speed of the wheels 120 with a simple configuration. Based on this, excessive speed of the transport vehicle 100 and abnormal operation of the transport vehicle 100 can be detected.

[0030] Furthermore, by making the length occupied by the first portion 131 longer than the length occupied by the second portion 132 in the circumferential direction around the rotation axis 125, it is possible to suppress erroneous detection of excessive speed even when the wheel 120 is swaying due to an external disturbance despite being under stop control. Furthermore, by arranging the first sensor 141 and the second sensor 142 in inverted positions so that they do not simultaneously detect the second portion 132, it becomes possible to determine an abnormality in the sensors when the determination device 150 acquires signals that simultaneously detect the second portion 132.

[0031] The present invention is not limited to the above-described embodiments. For example, the present invention may be embodied in another embodiment by arbitrarily combining the components described in this specification or by excluding some of the components. Furthermore, the present invention also includes various modifications that would occur to a person skilled in the art without departing from the spirit of the present invention, i.e., the meaning of the wording of the claims.

[0032] For example, as shown in FIG. 7, the object to be detected 130 may be a circular plate arranged perpendicular to the rotation axis 125, and may have a first portion 131 which is the peripheral edge of the circular plate, and a second portion 132 which is a slit-shaped notch.

[0033] 8, the object to be detected 130 may be provided on the surface of the axle 123 or the like. For example, the sensor may be a reflective photoelectric sensor, with the first portion 131 having a highly reflective surface and the second portion 132 having a relatively low reflective surface. The location where the object to be detected 130 is provided is not limited to the axle 123, and the object to be detected 130 may be provided on the wheel 120 or the like.

[0034] In addition, the transport vehicle 100 has a high-speed mode that is adopted when the vehicle is empty and a low-speed mode that is adopted when the vehicle is loaded, and the speed determination unit 151 may determine whether the vehicle is exceeding the speed limit using a first time threshold as the time threshold in the low-speed mode, and may determine whether the vehicle is exceeding the speed limit using a second time threshold that is shorter than the first time threshold as the time threshold in the high-speed mode.

[0035] Furthermore, although the above description deals with the case where excessive speed and sensor abnormality are detected by the detectable object 130 that rotates corresponding to the wheel 120 on one side (X+ side in the figure), in this embodiment, the transported vehicle 100 also detects changes between the first part 131 and the second part 132 of the detectable object 130 that rotates corresponding to the wheel 120 on the opposite side (X- side in the figure) using two sensors arranged at inverted positions. This allows redundancy in the determination of excessive speed of the transported vehicle 100. In other words, if excessive speed is detected in either one of the wheels 120 or the other wheel 120, the determination device 150 may output an excessive speed signal.

[0036] Alternatively, the object to be detected may be attached to the outside of wheel 120, and first sensor 141 and second sensor 142 may be disposed on a bracket connected to main body 110.

[0037] Furthermore, the object to be detected 130 may be a member in which two arc-shaped first and second portions 131 and 132 with different radii are arranged coaxially. A sensor may be arranged in each of the first and second portions 131 and 132, which are made of different materials. In this case, the first and second portions 131 and 132 are positioned or angled so that both sensors do not fail detection. This allows the object to be detected 130 to be shorter than half its circumference and to be located at a position other than the inversion position based on the rotation axis. [Industrial Applicability]

[0038] The present invention can be used in transport vehicles such as stacker cranes and unmanned trolleys that travel while holding loads. [Explanation of symbols]

[0039] 100 transport vehicles 110 Main Unit 120 wheels 121 Training wheels 122 Drive unit 123 axles 124 Control Device 125 Rotational Axis 130 Object to be detected 131 Part 1 132 Part 2 133 Mounting part 141 First Sensor 142 Second Sensor 150 Judgment device 151 Speed ​​judgment section 152 Abnormality determination section 153 Change detection unit 154 Off-Delay Section

Claims

1. A transport vehicle that travels by wheels attached to a body, a cylindrical detection object having a first portion and a second portion that rotate together with the rotation of the wheel, and that is disposed coaxially with the rotation axis of the wheel; a first sensor and a second sensor attached to the main body so that there is a timing when the first part can be simultaneously detected while the second part cannot be simultaneously detected; a determination device having a speed determination unit that determines that the vehicle is speeding based on whether a time from a change in the detection result by the first sensor to a change in the detection result by the second sensor is equal to or shorter than a time threshold; Equipped with The said part longer than half the circumference of the object to be detected, protruding in a direction along the rotation axis, The second part comprises: a cut-out portion other than the part in the detection object, The first sensor and the second sensor are The rotation axis is positioned at an inverted position. Transport vehicle.

2. A transport vehicle that travels by wheels attached to a body, a disc-shaped detection object having a first part and a second part that rotate together with the rotation of the wheel, the rotation axis of the wheel passing perpendicularly through the center; a first sensor and a second sensor attached to the main body so that there is a timing when the first part can be simultaneously detected while the second part cannot be simultaneously detected; a determination device having a speed determination unit that determines that the vehicle is speeding based on whether a time from a change in the detection result by the first sensor to a change in the detection result by the second sensor is equal to or shorter than a time threshold; Equipped with The said part longer than half the circumference of the object to be detected, protruding in a radial direction around the rotation axis, The second part comprises: a cut-out portion other than the part in the detection object, The first sensor and the second sensor are The rotation axis is positioned at an inverted position. Transport vehicle.

3. The transport vehicle is At least two of said wheels; At least two of the detection objects rotate together with the rotation of each of the wheels; At least two first sensors and at least two second sensors each detecting the object to be detected. The transport vehicle according to claim 1 or 2.

4. The determination device an abnormality determination unit that determines a sensor abnormality based on the detection of the second portion of the object to be detected by both the first sensor and the second sensor; The transport vehicle according to any one of claims 1 to 3.

5. a change detection unit that generates a first change pulse based on a change in the detection result of the first sensor; an off-delay unit that executes an off-delay according to the time threshold based on the first changing pulse, The speed determination unit When the off-delay by the off-delay unit is on and a change in the detection result of the second sensor occurs, it is determined that the vehicle is speeding. A transport vehicle according to any one of claims 1 to 4.

6. The speed determination unit In the low speed mode, a first time threshold is used as the time threshold to determine whether the vehicle is exceeding the speed limit; In the high-speed mode, a second time threshold that is shorter than the first time threshold is used as the time threshold to determine whether the vehicle is speeding. A transport vehicle according to any one of claims 1 to 5.

7. The speed determination unit The time from when the detection result of the second sensor changes to when the detection result of the first sensor changes is equal to or less than the time threshold, the speed is determined to be excessive. A transport vehicle according to any one of claims 1 to 6.

8. When the wheel is stopped and the first sensor and the second sensor are detecting the portion of the object to be detected, the length of the portion in the circumferential direction is long enough that both the first sensor and the second sensor can stably detect the portion even if the wheel vibrates. A transport vehicle according to any one of claims 1 to 7.

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