Carrier vehicle

Abstract

To provide a carrier vehicle capable of preventing unintentional stopping of the carrier vehicle.SOLUTION: A carrier vehicle 1 comprises: a protection area setting unit 11 for setting a protection area around a vehicle body; an OR operation unit 13 which outputs a result of an OR operation of a first signal which is in an ON state when no object is detected within the protection area, and a second signal that is in an ON state when an instruction is given to disable a function of the protection area, as a third signal which is in an ON state when the vehicle body is allowed to travel; and an abnormality detection unit 14 that detects an abnormality in a path which transmits the second signal to the OR operation unit based on the first signal, the second signal, and the third signal.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an autonomously driven guided vehicle. [Background technology]

[0002] Patent Document 1 below discloses an automatic guided vehicle (AGV) that travels autonomously on a floor surface. This automatic guided vehicle has laser scanners arranged on the front, back, left and right sides, and each laser scanner provides a rectangular sensing area on the front, back, left and right sides of the automatic guided vehicle. Each sensing area includes a protection area provided on the inside of the area and a warning area provided on the outside of the protection area. When a worker enters the warning area, the automatic guided vehicle decelerates, and when the worker enters the protection area, the automatic guided vehicle stops. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7137609 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when an automated guided vehicle with protective areas on the front, back, left and right sides approaches an object, for example by entering a narrow space, the automated guided vehicle will stop. Therefore, it would be convenient if the function of the protective area could be disabled when the automated guided vehicle enters a narrow space. However, if the signal line that disables the function of the protective area is disconnected, the function of the protective area will not be disabled, and the automated guided vehicle will stop when it enters the narrow space.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a transport vehicle that can be prevented from stopping unintentionally. [Means for solving the problem]

[0006] A transport vehicle according to one embodiment of the present invention includes a protection area setting unit that sets a protection area around a vehicle body, a logical OR operation unit that outputs the result of a logical OR operation of a first signal that is in an on state when no object is detected within the protection area and a second signal that is in an on state when an instruction to disable the function of the protection area has been received, as a third signal that is in an on state when the vehicle body is able to travel, and an abnormality detection unit that detects an abnormality in the path for transmitting the second signal to the logical OR operation unit based on the first signal, the second signal, and the third signal.

[0007] According to this aspect, by using a first signal that is turned on when no object is detected within the protection area, a second signal that is turned on when the function of the protection area is disabled, and a third signal that is the result of a logical OR operation of the first and second signals and is turned on when the vehicle body is able to travel, if it is found that a result that is inconsistent with the result of the logical OR operation when the function of the protection area is set to disabled is obtained, it is possible to detect that there is an abnormality in the path for sending the second signal for disabling the function of the protection area to the logical OR operation unit.

[0008] In the above aspect, the abnormality detection unit may detect that there is an abnormality in the path for transmitting the second signal to the logical OR calculation unit if the second signal set by the operator is in an on state indicating that an instruction has been given to disable the function of the protection area, the first signal is in an off state indicating that an object has been detected within the protection area, and the third signal is in an off state.

[0009] According to this aspect, if an operator disables the function of the protection area but an object is detected within the protection area and a result is output indicating that travel is impossible, it is possible to detect that there is an abnormality in the path for transmitting the second signal for disabling the function of the protection area to the logical OR calculation unit.

[0010] In the above aspect, when the path for transmitting the second signal to the logical sum calculation unit is normal, if the second signal set by the operator is in an on state indicating that an instruction has been given to disable the function of the protected area, the third signal may be in an on state.

[0011] According to this aspect, when the path for transmitting the second signal to the logical sum calculation unit is normal, if an operator disables the function of the protective area, the transport vehicle can continue to travel even if it enters a narrow space.

[0012] In the above aspect, when the path for transmitting the second signal to the logical sum calculation unit is normal, the first signal and the third signal may match if the second signal set by the operator is in an off state indicating that no instruction has been given to disable the function of the protected area.

[0013] According to this aspect, when the path for transmitting the second signal to the logical sum calculation unit is normal, if an operator activates the function of the protection area, it becomes possible to allow the vehicle body to run when no object is detected and to stop the vehicle body when an object is detected.

[0014] In the above aspect, the vehicle may further include a stop control unit that stops the vehicle body when the third signal is in an off state.

[0015] According to this aspect, when the first signal and the second signal are in the OFF state, that is, when an object is detected and the function of the protection area is active, it is possible to stop the vehicle body.

[0016] In the above aspect, the function of the protection area may be a function of stopping the vehicle body when an object is detected within the range of the protection area.

[0017] According to this aspect, when the protection area function is enabled, the vehicle body can be stopped when an object is detected within the protection area, whereas when the protection area function is disabled, it is possible to continue driving even if an object is detected within the protection area. Effect of the Invention

[0018] According to the present invention, it is possible to provide a transport vehicle that can be prevented from stopping unintentionally. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of a transport vehicle according to an embodiment, viewed from directly above; [Diagram 2] FIG. 1 is a schematic diagram showing a transport vehicle provided with a virtual bumper as viewed from directly above. [Diagram 3] FIG. 2 is a block diagram illustrating a physical configuration of a transportation vehicle. [Figure 4] FIG. 2 is a block diagram illustrating a functional configuration of a transportation vehicle. [Diagram 5] 11 is a diagram for explaining the content of a logical sum operation performed by a logical sum operation unit; FIG. [Figure 6] 10 is a flowchart for explaining an example of an operation of a transportation vehicle according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to the accompanying drawings, in which like reference numerals denote like or similar structures.

[0021] 1 is a schematic diagram of a transport vehicle 1 according to an embodiment, viewed from directly above. The transport vehicle 1 is an autonomously travelling device, and may be, for example, a transport platform vehicle that transports luggage or the like placed on the vehicle body, or a transport robot that transports luggage or the like. In this embodiment, a case where the transport vehicle 1 is a transport platform vehicle will be described as an example. The transport vehicle 1 can move in all directions 360 degrees automatically or manually.

[0022] The transport vehicle 1 is equipped with two sensors 2a and 2b. The sensors 2a and 2b are sensors that measure the distance to an object, and are, for example, a laser scanner, a Time Of Flight (TOF) sensor, a Light Detection and Ranging (LiDAR) sensor, etc. In this embodiment, a case will be described in which the sensors 2a and 2b are laser scanners that can scan a range of 270 degrees with laser light.

[0023] The scanning range Ra of the sensor 2a and the scanning range Rb of the sensor 2b partially overlap each other, and by combining the two scanning ranges, it is possible to scan the entire periphery of the transport vehicle 1. This makes it possible to detect objects that may be present around the transport vehicle 1 (in all directions).

[0024] The number of sensors mounted on the transport vehicle 1 is not limited to two, and may be one, or three or more. It is sufficient that the mounted sensor can detect objects present in all directions in which the transport vehicle 1 can move. Objects include, for example, passage walls, shelves and pipes arranged in the passage, other transport vehicles and people present in the passage, etc.

[0025] As shown in FIG. 2, the transport vehicle 1 is provided with a virtual bumper B around the vehicle body. The virtual bumper B is a virtual area formed within the scanning ranges Ra, Rb of the two sensors 2a, 2b, and is a protective area to prevent collision with objects. When an object is detected within the range of the virtual bumper B, the transport vehicle 1 stops. In other words, when an object detected by the sensors 2a, 2b is present within the range of the virtual bumper B, the transport vehicle 1 stops. By forming the virtual bumper B within the scanning ranges Ra, Rb of the sensors 2a, 2b, an object present within the range of the virtual bumper B can be detected using the measurement results of the sensors 2a, 2b.

[0026] It is preferable that the width W by which the virtual bumper B projects from the periphery of the vehicle body (hereinafter also referred to as the "virtual bumper width") be set to a length that ensures a distance that allows the vehicle body to stop without colliding with an object detected within the range of the virtual bumper B. This makes it possible to reliably stop the vehicle body without colliding with an object detected within the range of the virtual bumper B.

[0027] The physical configuration of the transport vehicle 1 will be described with reference to Fig. 3. As shown in the figure, the transport vehicle 1 includes, as its physical configuration, for example, two sensors 2a and 2b, a safety PLC (Programmable Logic Controller) 3, a PLC 4, a servo driver 5, four servo motors 6a, 6b, 6c, and 6d, and an input device 7.

[0028] Each of the sensors 2a and 2b is a distance measuring sensor that measures the distance to an object existing around the transport vehicle 1. The safety PLC 3 and PLC 4 are control devices that control each part of the transport vehicle 1. The safety PLC 3 and PLC 4 may be integrated into one PLC, or may be divided into three or more depending on their roles. The servo driver 5 supplies a drive voltage to the motor so that the motor follows a target value such as a speed command output from a controller such as the safety PLC 3 or PLC 4, and controls the position, speed, output torque, etc. of the motor.

[0029] Each of the servo motors 6a, 6b, 6c, and 6d includes a motor that drives a wheel and an encoder that detects the operation status of the motor. The wheel is a wheel that can move in all directions, and for example, an omniwheel can be used. The encoder feeds back the detected operation status of the motor to the servo driver 5.

[0030] The input device 7 functions as an input unit capable of transmitting various signals to the PLC 4 according to an operation instruction of an operator. The various signals include, for example, a mute signal, which will be described later. The input device 7 may be a terminal device that can be connected to the transport vehicle 1 via a network.

[0031] The functional configuration of the transport vehicle 1 will be described with reference to Fig. 4. As shown in the figure, the transport vehicle 1 includes, as its functional configuration, for example, a protection area setting unit 11, an object detection unit 12, a logical sum calculation unit 13, an abnormality detection unit 14, and a stop control unit 15.

[0032] The protection area setting unit 11 provides a virtual bumper B around the vehicle body in accordance with, for example, an operational instruction from an operator. The virtual bumper B is a virtual area, and has a function of stopping the vehicle body when an object is detected within this area.

[0033] The object detection unit 12 detects the presence of an object within the virtual bumper B based on the distance to the object measured by the sensors 2a and 2b.

[0034] Specifically, when the distance to the object exceeds the range of virtual bumper B, object detection unit 12 does not detect the presence of an object within virtual bumper B. In this case, object detection unit 12 outputs an object not detected signal in an ON state to logical sum operation unit 13. The object not detected signal will be described in detail later.

[0035] On the other hand, when the distance to the object falls within the range of virtual bumper B, object detection unit 12 detects that an object is present within virtual bumper B. In this case, object detection unit 12 outputs an object not detected signal in the OFF state to logical OR operation unit 13.

[0036] The logical sum operation unit 13 is physically a logic circuit (OR circuit) 3a, which outputs "1" if the input signal is in the on state and "0" if the input signal is in the off state, and outputs "1" if at least one of the inputs is "1", and outputs "0" if all of the inputs are "0".

[0037] The logical sum operation unit 13 in this embodiment receives as input an object not detected signal (first signal) that is in the ON state when no object is detected within the virtual bumper B, and a mute signal (second signal) that is in the ON state when an instruction is given to mute (disable) the function of the virtual bumper B, and outputs the result of the logical sum operation of the two input signals as a driving OK signal (third signal). The object not detected signal, the mute signal, and the driving OK signal will be described below.

[0038] The object non-detection signal is in an ON state when no object is detected within the range of the imaginary bumper B, and is in an OFF state when an object is detected within the range of the imaginary bumper B.

[0039] The mute signal is in the ON state when an instruction is given to mute the function of virtual bumper B, and is in the OFF state when an instruction is not given to mute the function of virtual bumper B. The function of virtual bumper B is to stop the vehicle body when an object is detected within the range of virtual bumper B.

[0040] The mute signal is set to either an ON state (disabling the function of virtual bumper B) or an OFF state (enabling the function of virtual bumper B), for example, by an operator operating the input device 7. In this embodiment, for example, the mute signal set to the ON state or the OFF state by the input device 7 is transmitted to the safety PLC 3 via the PLC 4 and input to the logic circuit 3a (logical OR operation unit 13) in the safety PLC 3.

[0041] The driving enable signal is a signal output as a result of a logical sum operation from the logical sum operation unit 13, and indicates that the vehicle body can be driven when it is in an on state corresponding to "1," and indicates that the vehicle body cannot be driven when it is in an off state corresponding to "0." Therefore, when the driving enable signal is in an off state, the vehicle body is stopped.

[0042] The travel-ready signal output from the OR operation unit 13 is transmitted from the safety PLC 3 to the PLC 4 and is used for abnormality detection in the abnormality detection unit 14, which will be described later.

[0043] With reference to FIG. 5, the relationship between the object undetected signal and the mute signal input to the logical sum operation unit 13 and the travel enable signal output from the logical sum operation unit 13 will be described.

[0044] (1) When an object not detected signal in the ON state and a mute signal in the ON state are input to the logical sum calculation unit 13, the logical sum calculation unit 13 outputs a driving enable signal in the ON state. This indicates that when no object is detected within the imaginary bumper B and the function of the imaginary bumper B is in the mute state, the vehicle body is in a state where it can drive.

[0045] (2) When an ON-state object no detection signal and an OFF-state mute signal are input to the logical sum calculation unit 13, the logical sum calculation unit 13 outputs an ON-state driving enable signal. This indicates that the vehicle body is ready to drive when no object is detected within the imaginary bumper B and the function of the imaginary bumper B is enabled.

[0046] (3) When an object not detected signal in the OFF state and a mute signal in the ON state are input to the logical sum calculation unit 13, the logical sum calculation unit 13 outputs a driving enable signal in the ON state. This indicates that when an object is detected within the imaginary bumper B and the function of the imaginary bumper B is in the mute state, the vehicle body is in a state where it can drive.

[0047] (4) When the OFF-state object not detected signal and the OFF-state mute signal are input to the OR operation unit 13, the OR operation unit 13 outputs an OFF-state driving enable signal. This indicates that when an object is detected within the imaginary bumper B and the function of the imaginary bumper B is enabled, the vehicle body cannot drive, i.e., the vehicle body is in a state to be stopped.

[0048] Here, when the path for transmitting the mute signal to the logical sum calculation unit 13 is normal, if the mute signal is in the on state, the driving permission signal will also be in the on state, whereas if the mute signal is in the off state, the object not detected signal and the driving permission signal will match.

[0049] In this embodiment, the path for transmitting the mute signal to the logical OR calculation unit 13 (hereinafter also referred to as the "mute signal transmission path") corresponds to the path connecting the PLC 4 and the logic circuit 3a (logical OR calculation unit 13) included in the safety PLC 3.

[0050] Returning to the description of Fig. 4, the abnormality detection unit 14 detects that an abnormality has occurred in the mute signal transmission path, based on the object undetected signal, the mute signal, and the travel OK signal.

[0051] Specifically, when the mute signal set by the input device 7 is in the on state, the object not detected signal is in the off state, and the driving permitted signal is in the off state, the abnormality detection unit 14 detects that there is an abnormality in the mute signal transmission path.

[0052] Furthermore, when the abnormality detection unit 14 detects that there is an abnormality, it may notify an operator of the abnormality by, for example, sounding an alarm or turning on a warning light.

[0053] When the travel enable signal output by the OR operation unit 13 is in the OFF state, the stop control unit 15 stops driving the motor to stop the vehicle body.

[0054] Next, an example of the operation of the transport vehicle 1 according to the embodiment will be described with reference to FIG.

[0055] First, the protection area setting unit 11 of the transportation vehicle 1 sets up a virtual bumper B around the vehicle body (step S101).

[0056] Next, the logical sum calculation unit 13 of the transport vehicle 1 calculates the logical sum of an object not detected signal, which is turned on when no object is detected within virtual bumper B, and a mute signal, which is turned on when an instruction has been given to mute the function of virtual bumper B (step S102).

[0057] Next, the stop control unit 15 of the transportation vehicle 1 judges whether the travel enable signal corresponding to the result of the logical sum calculated in the above step S102 is in the ON state (step S103). If this judgment is YES (step S103; YES), the process returns to the above step S102.

[0058] If it is determined in step S103 that the travel enable signal is not on (step S103; NO), the stop control unit 15 of the transport vehicle 1 stops driving the motor to stop the vehicle body (step S104).

[0059] Next, the abnormality detection unit 14 of the transportation vehicle 1 judges whether the mute signal set by the input device 7 is in the ON state (step S105). If this judgment is NO (step S105; NO), this operation ends.

[0060] If it is determined in step S105 that the mute signal set by the input device 7 is in the ON state (step S105; YES), the abnormality detection unit 14 of the transportation vehicle 1 detects that there is an abnormality in the mute signal transmission path (step S106). Then, this operation ends.

[0061] As described above, with the transport vehicle 1 of the embodiment, it is possible to detect an abnormality in the mute signal transmission path when it is found that a result that contradicts the result of the logical OR operation when the function of virtual bumper B is set to the mute state is obtained using the object not detected signal that is turned on when no object is detected within the range of virtual bumper B, the mute signal that is turned on when the function of virtual bumper B is set to the mute state, and the driving enable signal that is the result of the logical OR operation of the object not detected signal and the mute signal that is turned on when the vehicle body is able to drive.

[0062] Specifically, when an operator mutes the function of virtual bumper B, but an object is detected within the range of virtual bumper B and a result is output indicating that driving is impossible, it is possible to detect an abnormality in the path for transmitting a mute signal to the logical sum calculation unit 13 to mute the function of virtual bumper B, and to notify the operator of the abnormality.

[0063] Therefore, according to the guided vehicle 1 according to the embodiment, it is possible to prevent unintentional stopping.

[0064] In addition, according to the transport vehicle 1 of the embodiment, when the function of virtual bumper B is enabled, the vehicle body can be stopped when an object is detected within the range of virtual bumper B, whereas when the function of virtual bumper B is muted, the vehicle body can continue to run even if an object is detected within the range of virtual bumper B.

[0065] The above-described embodiment is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The elements of the embodiment, as well as their arrangement, shape, and size, are not limited to those shown in the examples, and can be changed as appropriate. Furthermore, the order of the above-described processing steps can be arbitrarily changed or executed in parallel as long as no inconsistency occurs in the processing content. [Explanation of symbols]

[0066] 1...transport vehicle, 2a, 2b...sensor, 3...safety PLC, 3a...logic circuit, 4...PLC, 5...servo driver, 6a, 6b, 6c, 6d...servo motor, 7...input device, 11...protection area setting unit, 12...object detection unit, 13...logical OR operation unit, 14...abnormality detection unit, 15...stop control unit, B...virtual bumper, Ra, Rb...scanning range

Claims

1. a protection area setting unit that sets a protection area around the vehicle body; a logical sum calculation unit that outputs a result of a logical sum calculation of a first signal indicating that an object has not been detected within the protection area and a second signal indicating that an instruction to disable the protection area has been issued as a third signal indicating that the vehicle body is allowed to travel; and an abnormality detection unit that detects, based on the first signal, the second signal, and the third signal, that an abnormality exists in a path for transmitting the second signal to the logical sum operation unit; A transport vehicle equipped with the above.

2. the abnormality detection unit detects that there is an abnormality in a path for transmitting the second signal to the logical sum operation unit if the second signal set by an operator is in an ON state indicating that an instruction has been given to disable the function of the protection area, the first signal is in an OFF state indicating that an object has been detected within the protection area, and the third signal is in an OFF state; The transport vehicle according to claim 1.

3. When a path for transmitting the second signal to the logical sum calculation unit is normal, if the second signal set by an operator is in an ON state indicating that an instruction has been given to disable the function of the protection area, the third signal is turned on. The transport vehicle according to claim 1.

4. When a path for transmitting the second signal to the logical sum calculation unit is normal, if the second signal set by an operator is in an off state indicating that an instruction to disable the function of the protection area has not been given, the first signal and the third signal match. The transport vehicle according to claim 1.

5. A stop control unit that stops the vehicle body when the third signal is in an off state. The transport vehicle according to claim 1.

6. The function of the protection area is to stop the vehicle body when an object is detected within the protection area. The transport vehicle according to claim 1.

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