JP4462175B2 - Transport system - Google Patents

Description

  The present invention relates to a transport system that transports an object to be transported by a plurality of autonomous mobile devices using a rechargeable battery as a drive source.

  2. Description of the Related Art Conventionally, in a factory, for example, there is a conveyor line system for transporting a pallet for transporting a workpiece to be processed using a pallet and collecting and repeatedly using an empty pallet. However, in such a system, the conveyance path is fixed to the line, and it is not possible to flexibly cope with process changes and layout changes. Therefore, an autonomous distributed type transport system using an autonomous mobile device (autonomous mobile robot) has been devised.

In the transport system for the autonomous distributed autonomous mobile device described above, when each autonomous mobile device uses a rechargeable battery as a drive source, charge management is important in order to operate this system smoothly. For this reason, for example, there is a system in which autonomous mobile devices that perform predetermined work respectively at a plurality of work stations are supplied with power from a power supply device and charge a rechargeable battery while the work is stopped at the work station. In this system, when an autonomous mobile device has stopped working for a work station after it has finished work at the work station, it may be necessary for the work station to stop another autonomous mobile device to perform the work. There is. Therefore, the host computer that manages the operation of the autonomous mobile device uses the operation data stored in advance and the data obtained through communication with the autonomous mobile device to make the autonomous mobile device that has completed the work other idle work stations or dedicated for charging. There is known a system in which a charging operation is continued by forcibly moving to a charging station (see, for example, Patent Document 1).
JP 2001-92529 A

  However, in the system as shown in Patent Document 1 described above, it is difficult to say that the operation amount itself or the time transition of the operation amount is not taken into consideration, and the operation is efficient.

  The present invention solves the above-mentioned problems, and a plurality of rechargeable batteries using a rechargeable battery as a drive source can easily realize the operation of the autonomous mobile device at a low cost when it is necessary for the minimum number of autonomous mobile devices for 24 hours. It aims at providing the efficient conveyance system by an autonomous mobile device.

In order to achieve the above-mentioned object, the invention according to claim 1 charges the rechargeable battery with a plurality of autonomous mobile devices that move by a moving means using the rechargeable battery as a drive source and convey the object to be conveyed to the destination. A transport system comprising: a charging device; and a transport control device that controls the autonomous mobile device to transport an object to be transported or charges the rechargeable battery by the charging device, wherein the autonomous mobile device is Position detecting means for acquiring a current position, route generating means for generating a route to a destination, the moving means based on the current position acquired by the position detecting means and the route generated by the route generating means. A movement control unit configured to control and move the autonomous mobile device, and a communication unit for wirelessly exchanging information with the conveyance control device, wherein the conveyance control device stores data on the predicted conveyance amount. A storage unit, causes the transportation operation and the charging operation based on the single transport amount of the predicted carry amount and number and autonomous mobile apparatus rechargeable autonomous mobile apparatus simultaneously by the charging time and the charging device of the rechargeable battery By transferring information wirelessly with each autonomous mobile device via the communication means, a transfer plan generating unit that generates a transfer plan that defines the number of vehicles per fixed time, to the autonomous mobile device based on the transfer plan The difference between calculating the difference between the conveyance amount of the conveyance plan and the actual conveyance amount, and the operation control unit that performs the conveyance operation control and preferentially performs the charging operation control for a low rechargeable battery voltage A transfer unit, and the transfer plan generation unit generates a transfer plan for adjustment in which the transfer amount for the next fixed time is increased or decreased based on the difference when the difference is greater than a predetermined value, The motion controller And it performs operation control of the autonomous mobile apparatus based on the transport plans for the adjustment.

According to the invention of claim 1, according to the transport plan at regular intervals based on the predicted transport amount, the charging time, the maximum number of simultaneously charged autonomous vehicles, that is , the number of autonomous mobile devices that can be charged simultaneously, and the single transport amount of the autonomous mobile device. , Transport operation control, and charging operation control with priority for those with low rechargeable battery voltage, so that the autonomous mobile device can be operated in a chargeable state when it is necessary for 24 hours with the minimum number of autonomous mobile devices Can be operated efficiently.

In addition, since it is possible to control the movement and charging of the autonomous mobile device based on an adjustment transportation plan that increases or decreases the transportation amount for a certain period of time, the actual transportation amount can be flexibly dealt with in the event of sudden transportation problems. It is possible to perform a transport operation in accordance with.

  Hereinafter, a transport system using a plurality of autonomous mobile devices using a rechargeable battery according to an embodiment of the present invention as a drive source will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows the system configuration of the transport system 1 according to the first embodiment, FIG. 2 (a) shows an example of the temporal change in the predicted transport amount referred to in the system 1, and FIG. 2 (b) A procedure for generating a transport plan for the predicted transport amount is shown, and FIGS. 3 and 4 respectively show a processing flow for determining a transport plan and charging operation in the present system. As shown in FIG. 1, the transport system 1 charges a rechargeable battery BT and a plurality of autonomous mobile devices 2 that are moved by a moving unit 11 using the rechargeable battery BT as a drive source and transport a transported object to a destination. A charging device 3 and a transport control device 4 for controlling the autonomous mobile device 2 to transport the object to be transported or charging the rechargeable battery BT by the charging device 3 are provided.

  The autonomous mobile device 2 described above is generated by the position detection unit 12 that acquires the current position, the route generation unit 13 that generates a route to the destination, and the current position acquired by the position detection unit 12 and the route generation unit 13. A movement control unit 14 that moves the autonomous mobile device 2 by controlling the movement unit 11 based on the route that has been made, and a communication unit 15 that exchanges information with the conveyance control device 4 wirelessly are provided.

  Further, the transport control device 4 includes a data storage unit 16 that stores the predicted transport amount, the predicted transport amount, the charging time of the rechargeable battery BT, the maximum number of simultaneous charging by the charging device 3, and the single transport amount of the autonomous mobile device 2. Based on the transfer plan generation unit 17 for generating a transfer plan in which the number of vehicles per fixed time for performing the transfer operation and the charging operation is determined, the communication means 18, and the communication means 15 of the autonomous mobile device 2 using this communication means. By exchanging information with each autonomous mobile device 2 wirelessly via the mobile phone, the autonomous mobile device 2 is controlled to perform the transport operation based on the transport plan, and is given priority to those with a low voltage of the rechargeable battery BT. And an operation control unit 19 that performs charging operation control.

  The above-mentioned moving means 11 includes, for example, left and right independent drive wheels that use the rechargeable battery BT as a drive source, and auxiliary wheels that rotate freely. The vehicle is steered by the difference in the rotational speed between the left and right drive wheels. In addition, encoders can be installed on the left and right drive wheels to read the rotation speed of the drive wheels, and the current position can be known by dead reckoning. Dead reckoning can be used as one of the position detection means 12 described below. The rechargeable battery BT is, for example, a lead storage battery, and can operate for 8 hours in actual operation by charging for 8 hours.

  The position detection unit 12 includes, for example, an environmental information detection device that detects environmental information such as walls and pillars around the movement path, or labels and signs arranged for position detection, and a self-position based on the detected environmental information. And environmental map information to be referred to in order to determine. As the environmental information detection device, for example, a laser radar, a camera, an ultrasonic sensor, or the like is used. The environmental information detection device includes, for example, an image processing device. The environment information detection device is also used as an obstacle detection device.

  Further, an RFID tag and a reader can be used as the other position detecting means 12. For example, an RFID tag is arranged on the movement route surface or the periphery of the route, and the autonomous mobile device 2 is provided with an RFID reader, thereby reading the information on the arrangement position of the RFID tag stored in the RFID tag to obtain the position coordinates. You may do it.

  The route generation unit 13 includes, for example, information on a basic route connecting a predetermined passing point (this is referred to as a node) and a passable node in the above-described environment map information. A travel route to the destination or the shortest node to the destination is determined by connecting basic routes that can be used under the conditions of the shortest distance and the shortest time.

  The movement control unit 14 can be configured as a set of processes or functions on an electronic computer having a general configuration including an MPU, a memory, an external storage device, a display device, an input device, and the like. The above-described environmental map information is stored in the memory of the movement control unit 14, for example. The movement control unit 14 acquires the current position by the position detection unit 12, generates a route by the route generation unit 13, controls the movement unit 11 based on the route, avoids an obstacle, or collides The autonomous mobile device 2 is moved while stopping or detouring for avoidance.

  The data storage unit 16 of the transport control device 4 stores data such as the predicted transport amount, the charging time of the rechargeable battery, the maximum number of simultaneous charging by the charging device 3, and the single transport amount of the autonomous mobile device. For example, the predicted transport amount changes as shown in FIG. The conveyance control device 4 refers to such predicted conveyance amount data and creates a conveyance plan via the conveyance plan generation unit 17. The predicted transport amount to be referred to is obtained by statistically processing the transport amount per unit time per day, and is created by giving a margin to the maximum value in past performance data. In other words, the maximum value is a numerical value that is statistically guaranteed that it usually does not exceed this quantity. In FIG. 2B, the total transport amount is rearranged and displayed. That is, the areas of the portions shown in dotted patterns in FIGS. 2A and 2B indicate the transport amount, and these areas are equal in both drawings.

  Next, generation of a conveyance plan by the conveyance plan generation unit 17 will be described according to the example shown in FIGS. The example shown here is a transportation plan for 24 hours a day, and the day is divided into 24 parts with 1 hour as a unit of a fixed time. This fixed time can be arbitrarily set according to the situation of the conveyance object. Moreover, as a premise, it is assumed that the charging time of the autonomous mobile device 2 is H hours, and the daily operation time is (24-H) hours. Furthermore, the amount that the autonomous mobile device 2 can carry at one time is n (pieces / time), and the time required for one conveyance is t (hour / time). The total number of autonomous mobile devices 2 required to complete the transport of the total transport amount is set to x (times), where N is the total transport amount per day, and x is the number of times each autonomous mobile device 2 can be operated per day. Let y (unit).

  Based on the above premise, as shown in FIG. 3, the transport plan generation unit 17 first obtains the predicted transport amount per unit time (S1), and obtains the total predicted transport amount, that is, N (pieces) ( S2). Next, by dividing this N (pieces) by a single carrying amount n (pieces / time) of one autonomous mobile device 2, a total number of times P (times) necessary for one day is obtained (S3). . That is, P (times) = N (pieces) / n (pieces / time) = N / n (times). The total number of times of conveyance is the number of cells shown in FIG. Furthermore, the number of times x that can be transported by one autonomous mobile device 2 per day using the operating time (24-H) (hours) obtained by subtracting the charging time H (hours) of the rechargeable battery BT from 24 hours per day x (Times) is obtained (S4). That is, x (times) = (24−H) / t (times) is obtained using the time t (hour / time) required for one transfer.

  Next, the total number of times of transportation P (times) required by the autonomous mobile device 2 required in one day is divided by the number of times x (number of times) that can be transported by one autonomous mobile device 2 per day. Thus, the number y (units) of the autonomous mobile devices 2 necessary for one day is obtained (S5). Here, in order to clearly indicate that x (times) is per vehicle, the unit is changed to x (times / unit). The desired number y is y (unit) = P (times) ÷ x (times / unit) = P / x (units). This is also expressed as y (stand) = N / (nx) (base) = N · t / (n · (24−H)) (base). When the number y is a fraction, the number rounded up is the number.

  Furthermore, the number of autonomous mobile devices y (units) necessary for the above-mentioned day is distributed according to the ratio of the predicted transport amount per unit time in the predicted transport amount data, that is, every hour in the present example. Thereby, the number of the autonomous mobile devices 2 in operation per unit time per day is obtained. For example, if the autonomous mobile device 2 requires 7 units (y = 7) per day and the operation time excluding the charging time is 12 hours, 7 (units / day) × 12 (hours) = 84 (units · (Hour / day) is distributed to approximate the ratio of the expected transport amount. Further, the number of autonomous mobile devices necessary for the obtained day is calculated as the number of charging devices necessary to operate continuously every day (S6). It is checked whether this number exceeds the maximum number of simultaneous charging by the charging device 3 (S7).

  If the required number of charging devices 3 exceeds the maximum number of simultaneous chargings by the charging device 3 (No in S7), increase the number of charging devices 3 or decrease the number of autonomous mobile devices operating per unit time. It adjusts so that it can charge continuously, reducing a conveyance amount (S8). This adjustment is determined appropriately by the operator in consideration of the production quantity and the cost of increasing the charging device. However, normally, it is desirable that the number of charging devices 3 has sufficient capacity as compared with the number of autonomous mobile devices 2. Finally, the transportation plan is generated by converting the number of the autonomous mobile devices 2 into a transportable amount (S9).

  The conveyance plan generated as described above is referred to by the operation control unit 19 of the conveyance control device 4, and actual conveyance is performed as shown in FIG. First, the operation control unit 19 acquires the maximum conveyance amount for a certain time at the current time from the conveyance plan (S11). Next, the operation control unit 19 wirelessly exchanges information with each autonomous mobile device 2 via the communication means 15 and 18, thereby acquiring the current actual transport amount (S12).

  Next, the operation control unit 19 compares the conveyance amount of the conveyance plan with the actual conveyance amount. If the current conveyance amount exceeds the planned conveyance amount (Yes in S13), the operation control unit 19 sets the current conveyance amount. The planned transport amount is corrected and consideration is given so as not to exceed the transport capability of the autonomous mobile device 2 (S14). However, since the portion that could not be transported remains, consideration is given so that the remaining transport can be processed in the next fixed time in addition to the actual transport amount in the next fixed time (S15).

  After performing the above-described steps S14 and S15, or when the current transport amount does not exceed the planned transport amount (Yes in S13), the required number of autonomous mobile devices 2 is calculated from the requested transport amount. (S16). Furthermore, the current voltage value of the rechargeable battery BT of each autonomous mobile device 2 is acquired via the communication means 15 and 18 (S17).

Thereafter, the operation control unit 19 charges the autonomous mobile device 2 that needs to be operated from among a large number of autonomous mobile devices 2 (S18), and transports other than the autonomous mobile device 2 to be charged ( S19). In selecting whether to charge or transport, the operation control unit 19 first starts from the autonomous mobile device 2 having the highest voltage value of the rechargeable battery BT of each autonomous mobile device 2 acquired by the wireless communication means 15 and 18. Select to run on. In addition, among the autonomous mobile devices 2 that do not need to remain in operation, the autonomous mobile device 2 with a low voltage of the rechargeable battery BT charges the rechargeable battery BT and suppresses power consumption. Turn off the power except for. In addition, among the autonomous mobile devices 2 that do not need to be transported, the autonomous mobile device 2 that has been charged or has the highest voltage of the rechargeable battery BT is not turned off so that it can be transported immediately. stand by.

  As described above, according to the transport system 1 of the first embodiment, according to the transport plan at regular intervals based on the predicted transport amount, the charging time, the maximum simultaneous charge number, and the single transport amount of the autonomous mobile device, Since the transport operation control and the charge operation control are performed preferentially for those with a low rechargeable battery voltage, the autonomous mobile device can be operated in a chargeable state when necessary for 24 hours with the minimum number of autonomous mobile devices. Operation can be realized. Further, for example, if the charging device is provided without being distributed in many places, the transportation control and charging operation control of the autonomous mobile device can be facilitated, and the transport system can be constructed at low cost.

(Second Embodiment)
FIG. 5 shows a system configuration of the transport system 1 according to the second embodiment. The transfer system 1 is different from the first embodiment described above in that the transfer control device 4 further includes a difference calculation unit 5, and is the same as the first embodiment. The difference calculation unit 5 calculates a difference between the conveyance amount of the conveyance plan generated by the conveyance plan generation unit 17 and the actual conveyance amount. And the conveyance plan production | generation part 17 produces | generates the conveyance plan for adjustment which increased / decreased the conveyance amount of the next fixed time based on a difference, when the difference calculated by the difference calculation part 5 is larger than predetermined value, The operation control unit 19 controls the operation of the autonomous mobile device 2 based on the adjustment transportation plan.

  According to the operation control based on the adjustment conveyance plan in which the conveyance amount for a certain period of time is increased or decreased, the operation control of the autonomous mobile device 2 can be performed, so that it is possible to flexibly cope with a sudden problem in conveyance. In addition, it is possible to perform a transport operation in accordance with an actual transport amount dynamically or in real time.

  The present invention is not limited to the above-described configuration, and various modifications can be made. The procedure and preconditions for generating the transfer plan described above are merely examples, and various modifications can be made. For example, values such as the charging time H, the transport amount n per vehicle, the time t required for one transport, and the like are values common to each autonomous mobile device 2 (these are, for example, an average value, a representative value, The maximum value or the minimum value) is given, but it is changed individually depending on the state of the rechargeable battery BT, the state of each autonomous mobile device 2, the state and type of the transport location and the transported object, etc. Can be given or have multiple values. Further, in the present transport system 1, the target time for transport plan creation is not limited to one day, that is, 24 hours. For example, a transportation plan such as 12 hours or 8 hours can be created in accordance with a time width such as 2 shifts or 3 shifts of the work site.

The system block diagram about the conveyance system which concerns on the 1st Embodiment of this invention. (A) is a graph which shows the example of the time change of the estimated conveyance amount referred by a system same as the above, (b) is a graph explaining the procedure which produces | generates the conveyance plan with respect to the estimated conveyance amount. The flowchart of the conveyance plan determination in a system same as the above. The flowchart of the charging operation in a system same as the above. The system block diagram about the conveyance system which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer system 2 Autonomous mobile device 3 Charging device 4 Transfer control device 5 Difference calculation part 11 Movement means 12 Position detection means 13 Path generation means 14 Movement control part 15 Communication means 16 Data storage part 17 Transfer plan generation part 18 Operation control part 19 Communication means BT Rechargeable battery

Claims (1)

A plurality of autonomous mobile devices that move by a moving means using a rechargeable battery as a drive source to transport a transported object to a destination, a charging device that charges the rechargeable battery, and a transported object that controls the autonomous mobile device Or a transport control device that charges the rechargeable battery with the charging device,
The autonomous mobile device is
Position detection means for acquiring a current position;
Route generation means for generating a route to the destination;
A movement control unit that moves the autonomous mobile device by controlling the moving unit based on the current position acquired by the position detecting unit and the route generated by the route generating unit;
Communication means for exchanging information wirelessly with the transport control device,
The transfer control device
A data storage unit storing the predicted transport amount;
Every predetermined time for carrying and carrying operations based on the estimated carrying amount, the charging time of the rechargeable battery, the number of autonomous mobile devices that can be charged simultaneously by the charging device, and the single carrying amount of the autonomous mobile device. A transport plan generator for generating a transport plan with a fixed number of units;
By exchanging information wirelessly with each autonomous mobile device via the communication means, the transport operation control is performed on the autonomous mobile device based on the transport plan, and the rechargeable battery voltage is low. An operation control unit for performing charge operation control with priority,
A difference calculation unit for calculating a difference between the conveyance amount of the conveyance plan and the actual conveyance amount ,
The transport plan generation unit generates a transport plan for adjustment in which the transport amount for the next fixed time is increased or decreased based on the difference when the difference is greater than a predetermined value,
The said operation control part performs operation control of an autonomous mobile apparatus based on the said conveyance plan for adjustment, The conveyance system characterized by the above-mentioned.

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