Methods for path planning of transport vehicles and transport vehicle control system

Abstract

This invention discloses a path planning method and control system for a transport vehicle. The path planning method includes a dynamic cost table reading step, a path planning step, and a dispatching step. The path planning step calculates multiple planned paths based on the dynamic cost table using a path planning algorithm. The dispatching step selects the planned path with the lowest travel time cost as the dispatching path, enabling the transport vehicle to move along the dispatching path to its destination. The path planning method and control system of this invention can plan dispatching paths that allow the transport vehicle to move to its destination with the lowest travel time cost.

Description

Technical Field

[0001] The present invention relates to a path planning method and a control system, in particular to a path planning method and a control system for a transport vehicle. Prior Art

[0002] Common path planning methods for aerial transport vehicles utilize algorithms such as the A-Star algorithm and Dijkstra's algorithm to calculate the shortest path from the vehicle's current location to its destination, allowing the vehicle to move directly along this shortest path. However, in practice, due to the many variables involved in the vehicle's movement on the track, the time taken to reach the destination using the shortest path may not always be the shortest. Summary of the Invention

[0003] The present invention discloses a transport vehicle path planning method and a transport vehicle control system, which are mainly used to improve the shortest path planned by the existing transport vehicle path planning method, which does not necessarily enable the transport vehicle to move to the destination in the relatively shortest time.

[0004] One embodiment of the present invention discloses a path planning method for a transport vehicle, which is suitable for execution by a processing device of a transport vehicle control system. After receiving a transport information, the processing device can execute the path planning method for the transport vehicle to determine a plurality of road sections for controlling a transport vehicle to move from a current position to a destination; the transport information includes a destination data; the path planning method for the transport vehicle includes the following steps: a dynamic cost table reading step: reading a dynamic cost table to obtain an average passing second for each road section; the dynamic cost table includes N passing seconds corresponding to each road section; the average passing second is the total average of the N passing seconds corresponding to the road section in the dynamic cost table; wherein N is a positive integer greater than 2; the dynamic cost table is stored in a memory of the transport vehicle control system; a path A planning step: based on the current position, destination data and dynamic cost table, a path planning algorithm is used to generate multiple planned paths; a dispatching step: transmitting movement information to the transport vehicle to control the transport vehicle to move along a dispatching path from the current position to the destination; the dispatching path is the planned path with the lowest movement time cost; the movement time cost is the sum of the average passing seconds corresponding to all road sections included in the planned path; wherein, when each transport vehicle passes through any road section in a running state, the processing device will replace one of the passing seconds of the corresponding road section in the dynamic cost table with the real-time passing seconds spent by the transport vehicle through the road section; when the transport vehicle passes through the road section in a running state, the transport vehicle does not perform a transport operation or a parking operation in the road section based on any movement information.

[0005] One embodiment of the present invention discloses a transport vehicle control system, which includes: multiple tracks, multiple transport vehicles and a processing device. At least one workstation is set around part of the track; each transport vehicle can move to any workstation along the track to perform a transport operation; the processing device is communicatively connected to each transport vehicle; after receiving a transport information, the processing device can execute a transport vehicle path planning method to determine the road section that one of the transport vehicles travels through from a current position to a destination; the transport information includes a destination data; wherein, the transport vehicle path planning method includes the following steps: a dynamic cost table reading step: reading a dynamic cost table to obtain an average passing second for each road section; the dynamic cost table includes N passing seconds corresponding to each road section, and the average passing second is the total average of the N passing seconds corresponding to the road section in the dynamic cost table; wherein N is a positive integer greater than 2; the dynamic cost table is stored in the transport vehicle control system a storage device of the system; a path planning step: generating a plurality of planned paths by using a path planning algorithm based on the current position, destination data and dynamic cost table; a vehicle dispatching step: transmitting movement information to the transport vehicle to control the transport vehicle to move from the current position to the destination along a dispatching path; the dispatching path is a planned path with the lowest movement time cost; the movement time cost is the sum of the average passing seconds corresponding to all road sections included in the planned path; wherein, when each transport vehicle passes through any road section in a running state, the processing device replaces one of the passing seconds of the corresponding road section in the dynamic cost table with the real-time passing seconds spent by the transport vehicle through the road section; when the transport vehicle passes through the road section in a running state, the transport vehicle does not perform a transport operation or a parking operation in the road section based on any transport information.

[0006] In summary, the path planning method and control system of the transport vehicle of the present invention, through the design of the dynamic cost table reading step, the path planning step and the vehicle dispatching step, the second judgment step and the updating step can allow the processing device to plan the vehicle dispatching path with the lowest moving time cost.

[0007] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, such description and drawings are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. Simple diagram description

[0008] FIG1 is a schematic diagram of a transport vehicle control system according to the present invention.

[0009] FIG2 is a block diagram of a transport vehicle control system of the transport vehicle.

[0010] FIG3 is a flow chart of a path planning method for a transport vehicle.

[0011] FIG4 is a partial flow chart of a method for path planning of a transport vehicle.

[0012] FIG. 5 is a flow chart showing a checking procedure of the path planning method for a transport vehicle according to the present invention.

[0013] FIG6 is a schematic diagram of another embodiment of a transport vehicle control system according to the present invention. Implementation Method

[0014] In the following description, if it is indicated to refer to a specific figure or as shown in a specific figure, it is only used to emphasize that most of the relevant content described in the subsequent description appears in the specific figure, but it does not limit the subsequent description to only referring to the specific figure.

[0015] Please refer to Figures 1 to 3 together. Figure 1 is a schematic diagram of the transport vehicle control system of the present invention, Figure 2 is a block diagram of the transport vehicle control system of the transport vehicle, and Figure 3 is a flow diagram of the path planning method of the transport vehicle.

[0016] The transport vehicle control system 100 of the present invention comprises multiple tracks, a processing device 1, multiple transport vehicles 2, and a storage container 3. At least one workstation is located around a portion of the tracks. For ease of explanation, Figure 1 shows only a single transport vehicle 2 and two workstations, X1 and X2. Each of the sections R01-R20 shown in Figure 1 is comprised of at least one track.

[0017] Each transport vehicle 2 receives movement information 11 transmitted by the processing device 1 and moves along the track to any workstation to perform a transport operation. Each transport vehicle 2 is, for example, an overhead hoist transfer (HOT) vehicle. The number and type of tracks included in the transport vehicle control system 100 are not limited. For example, some tracks may be straight, some may be curved, and at least some of the tracks may be interconnected to form a closed path.

[0018] The processing device 1 is communicatively connected to each transport vehicle 2. The processing device 1 is electrically connected to a storage device 3. The storage device 3 may be a hard drive, memory, or the like, without limitation. In one embodiment, the processing device 1 and storage device 3 may be integrated. In one embodiment, the processing device 1 may be a computer, and the storage device 3 may be a hard drive.

[0019] After receiving transport information 201, the processing device 1 can execute the transport vehicle path planning method of the present invention to determine the route that one of the transport vehicles 2 will take to move from a current location to a destination. The current location refers to the current location of the transport vehicle 2. The transport information 201 includes destination information. In practice, the processing device 1 receives the transport information 201 transmitted by a material control system 200 (MCS), for example.

[0020] The path planning method for the transport vehicle includes the following steps:

[0021] A dynamic cost table reading step S11: reading a dynamic cost table 31 to obtain an average passing time for each road segment; the dynamic cost table 31 includes N passing times corresponding to each road segment, and the average passing time is the total average of the N passing times corresponding to the road segment in the dynamic cost table 31; N is a positive integer greater than 2; the dynamic cost table 31 is stored in the memory 3;

[0022] A path planning step S12: Based on the current location, destination data and dynamic cost table, a path planning algorithm is used to generate multiple planned paths;

[0023] A vehicle dispatching step S13: transmitting movement information 11 to the transport vehicle 2 to control the transport vehicle 2 to move from the current position to the destination along a dispatching route; the dispatching route is a planned route with the lowest travel time cost; the travel time cost is the sum of the average travel time seconds corresponding to all road segments included in the planned route.

[0024] When each transport vehicle 2 passes through any road segment in an operational state, the processing device 1 replaces the corresponding road segment's transit seconds in the dynamic cost table 31 with the real-time transit seconds spent by the transport vehicle 2 through the road segment. While the transport vehicle 2 passes through the road segment in an operational state, the transport vehicle 2 does not perform any transporting operation or parking operation in the road segment based on any movement information 11.

[0025] The path planning algorithm may be a conventional cost-based path planning algorithm such as the A-Star algorithm or Dijkstra's algorithm, but is not limited to this. In the path planning step S12, the average travel time for each road segment, as contained in the dynamic cost table 31, and the unique identification data corresponding to each road segment are input into the path planning algorithm. This allows the path planning algorithm to use the average travel time for each road segment as a cost to plan a low-cost path from the current location to the destination.

[0026] In practical applications, the transport vehicle 2 includes a processor 21, at least one sensor 22, and at least one reader 23. As the transport vehicle 2 moves along the track, the processor 21 of the transport vehicle 2 simultaneously receives sensing signals generated by multiple sensors 22 and controls the drive module of the transport vehicle 2 to accelerate or decelerate accordingly.

[0027] Each track may be surrounded by multiple marking units (e.g., various barcodes), each of which stores unique location data 231. Each transport vehicle's reader 23 reads the location data 231 stored in the marking unit and transmits this location data 231 back to the processing device 1. The processing device 1 can then determine the current location of the transport vehicle 2 based on this location data 231.

[0028] The processor 21 of each transport vehicle 2 may store multiple endpoint data 211. When the reader 23 of the transport vehicle 2 reads the location data 231 of the marking unit, the processor 21 of the transport vehicle 2 may compare the location data 231 with the endpoint data 211. If the processor 21 determines that the location data 231 and the endpoint data 211 are the same, the processor 21 will determine that the transport vehicle 2 has just entered a road section. At this time, the processor 21 will start counting until the processor 21 determines that the location data 231 read by the reader 23 is the same as the other endpoint data 211 (indicating that the transport vehicle 2 has passed the other endpoint of the road section). The processor 21 will then stop counting and transmit the recorded total time (i.e., the aforementioned instantaneous passing seconds) to the processing device 1.

[0029] When processor 21 determines that truck 2 has just entered a road section, processor 21 may transmit status information 212 to processing device 1. Status information 212 includes location data 231 (or endpoint data 211). Processing device 1 can thus determine that truck 2 has entered a road section through status information 212. Similarly, when processor 21 determines that truck 2 has left a road section, processor 21 may again transmit status information 212 to processing device 1. This status information 212 may also include the total time truck 2 has spent traversing the road section (i.e., the real-time transit seconds). This allows processing device 1 to determine that truck 2 has left the road section. Because truck 2 transmits status information 212 to processing device 1 both upon entering and upon leaving a road section, processing device 1 can also calculate the real-time transit seconds for truck 2 to have passed through a road section based on the time between two successive transmissions of status information 212 from the same truck 2.

[0030] In practical applications, the endpoints of each section can be: the position along the track where the transport vehicle 2 is preparing to enter a curve, exit a curve, enter a divergence, exit a divergence, or a workstation. The divergence position refers to the point before two tracks intersect. In practice, transport vehicles 2 manufactured by different manufacturers may utilize different methods to smoothly navigate along curves or diverging tracks. Therefore, the preparation time required for different transport vehicles 2 before entering a curve may not be the same. Therefore, the actual endpoints of each section can be set based on actual needs.

[0031] In actual applications, when the sensor 22 of the transporter 2 senses an obstacle in the direction of travel of the transporter 2, the transporter 2 can transmit status information 212 to the processing device 1, and the status information 212 also includes obstacle data 2121; when the processor 21 of the transporter 2 determines that an abnormality has occurred in the transporter 2 (for example, the transporter 2 cannot move, etc.), it can transmit the status information 212 to the processing device 1, and the status information 212 also includes fault data 2122. In this way, the processing device 1 can know the position and status of each transporter 2 (for example, encountering an obstacle or having a fault) through the status information 212 transmitted by each transporter 2.

[0032] As described above, the transporter route planning method of the present invention, through the dynamic cost table reading step S11, route planning step S12, and vehicle dispatching step S13, allows transporter 2 to move from its current location to its destination along the dispatched route with the lowest travel time cost. Because the processing device 1 continuously updates the real-time transit time for each road segment in the dynamic cost table 31, the average transit time corresponding to each road segment in the dynamic cost table 31 effectively reflects the real-time situation of each transporter 2 as it passes through each road segment. This ensures that the ultimately planned dispatched route is one of the routes that will allow transporter 2 to reach its destination the fastest.

[0033] Common existing route planning methods often use the current location and destination of the transport vehicle 2 to plan the shortest path. This planning approach only considers the shortest path and does not take into account the current status of each path. Therefore, in practice, the transport vehicle 2 may not reach its destination in the shortest time. For example, suppose that path A is the shortest path and path B is not the shortest path. However, due to various factors, a certain section of path A causes the transport vehicle 2 to autonomously reduce its speed when passing through it. In this scenario, the transport vehicle 2 will actually reach its destination faster by following path B. For example, path A may include multiple curves, requiring the transport vehicle to reduce its speed each time it passes through a curve. Alternatively, path A may contain multiple diverging points, requiring the transport vehicle's processor to frequently control the transport vehicle's switching mechanism (commonly known as a handover mechanism) to ensure smooth movement along one of the tracks. This may also lead to traffic congestion on path A (described in detail later). On the other hand, in the path planning method for the transport vehicle of the present invention, when the above situation exists on path A, the average travel time corresponding to the road section in the dynamic cost table will be updated and increased. In the path planning step S12, the travel time cost of path A will not be the lowest. Therefore, the final dispatch path will not be path A.

[0034] In practical applications, the dynamic cost table can include the names of all road segments and at least two corresponding transit time and average transit time for each segment. For example, as shown in Table 1 below, which shows a portion of a dynamic cost table, two trucks 2 successively passed through segment R01, taking 3 seconds and 2.6 seconds, respectively; two trucks 2 successively passed through segment R02, taking 1.5 seconds and 1.3 seconds, respectively; and two trucks 2 successively passed through segment R03, taking 1 second and 1.2 seconds, respectively. In this example, in the dynamic cost table reading step S11, after the processing device reads the dynamic cost table (Table 1), it can find that the average transit times corresponding to segments R01, R02, and R03 are 2.8 seconds, 1.4 seconds, and 1.1 seconds, respectively. It should be noted that Table 1 only shows that the dynamic cost table records the first two passing seconds of each road section, that is, N=2, but N can also be a positive integer greater than 3. The specific number of N can be designed according to actual needs.

[0035] Table 1: Road section name The number of seconds it took to pass the previous time The number of seconds it took to pass the first two times Real-time average seconds R01 3 2.6 2.8 R02 1.5 1.3 1.4 R03 1 1.2 1.1

[0036] As shown in Table 1 above, assuming that a transport vehicle 2 has just been in operation and takes 2.8 seconds to pass through the road section named R01, the processing device will update Table 1 above, and the dynamic cost table will be updated from Table 1 above to the state of Table 2 below.

[0037] Table 2: Road section name The number of seconds it took to pass the previous time The number of seconds it took to pass the first two times Real-time average seconds R01 2.8 3 2.9 R02 1.5 1.3 1.4 R03 1 1.2 1.1

[0038] As shown in FIG1 , assuming that the dynamic cost table is Table 3 below, and the processing device receives the transport information 201 and controls the transport vehicle 2 to move from its current position (i.e., road section R01) to the workstation X2 for transporting operations, the processing device will obtain two planned paths P1 and P2 after executing the path planning step S12. The planned path P1 includes a total of 10 road sections, which are, in order, road sections R02, R03, R11, R12, R13, R14, R15, R16, R17, and R18. The planned path P2 includes a total of 14 road sections, which are, in order, road sections R02, R03, R04, R05, R06, R07, R08, R09, R10, R14, R15, R16, R17, and R18.

[0039] Table 3: Road section name The number of seconds it took to pass the previous time The number of seconds it took to pass the first two times Real-time average seconds R01 3.0 3.2 3.1 R02 2 1.8 1.9 R03 3.2 3.0 3.1 R04 2.2 2.2 2.2 R05 3.2 3.2 3.2 R06 2.2 2.4 2.3 R07 2.8 2.6 2.7 R08 1.9 2.1 2.0 R09 2.9 2.9 2.9 R10 2.0 2.2 2.2 R11 2.5 2.5 2.5 R12 18 16 17 R13 2.5 2.5 2.5 R14 3.2 3.1 3.2 R15 2.1 2.1 2.1 R16 3.0 3.0 3.0 R17 2.2 2.4 2.3 R18 6.2 6.1 6.2

[0040] As shown in Table 3 and FIG1 , assuming that when transport vehicle 2 moves from road section R03 to road section R04, the processor 21 of transport vehicle 2 does not need to control the conversion mechanism (i.e., commonly known as a handover mechanism in the industry), and transport vehicle 2 can move directly from road section R03 to road section R04. Furthermore, when transport vehicle 2 moves from road section R10 to road section R14, the processor 21 of transport vehicle 2 does not need to control the conversion mechanism, and transport vehicle 2 can move directly from road section R10 to road section R14. Specifically, when the transport vehicle 2 is at the intersection of road section R03, road section R04, and road section R11 (i.e., the divergence point), the processor 21 of the transport vehicle 2 will decide whether to control the conversion mechanism based on the road section that the transport vehicle 2 will subsequently travel. If the transport vehicle 2 is to move along road section R04, the processor 21 does not need to control the conversion mechanism, and the processor 21 will control the transport vehicle 2 to move directly forward. Conversely, when the processor 21 determines that the transport vehicle 2 is to move along road section R11, the processor 21 will first control the conversion mechanism and wait for the conversion mechanism to complete the conversion before controlling the transport vehicle 2 to move forward.

[0041] As described above, the time required for the transport vehicle 2 to pass through the road section R04 is less than the time required for the transport vehicle 2 to pass through the road section R11, and the time required for the transport vehicle 2 to pass through the road section R10 is less than the time required for the transport vehicle 2 to pass through the road section R13.

[0042] In the above example, after the processing device 1 executes the path planning step S12, it will calculate the movement time costs of the planned paths P1 and P2, which are 43.8 seconds and 39.3 seconds, respectively. The processing device 1 will use the planned path P2 as the dispatch path for the transport vehicle 2B. Then, after the transport vehicle 2B receives the movement information 11 transmitted by the processing device 1, it will move from its current location to the workstation X2 along the planned path P2 based on the movement information.

[0043] Continuing with the above example, assuming that the total length of planned path P1 shown in FIG1 is shorter than the total length of planned path P2, then in conventional technology, after the processing device obtains planned paths P1 and P2, it will directly move the transport vehicle 2 along the planned path P1 with the shortest total length to workstation X2. As can be seen from the above description, the time required for the transport vehicle to move along path P1 is 43.8 seconds, which is longer than the time required to move along path P2 (39.3 seconds). Therefore, moving the transport vehicle along path P1 planned by conventional technology will take a longer time, resulting in the transport vehicle not being able to move in the most efficient manner.

[0044] As described above, the transport vehicle control system 100 and the transport vehicle path planning method of the present invention, through the design of the dynamic cost table reading step S11, the path planning step S12, and the vehicle dispatching step S13, allow the processing device to plan a vehicle dispatching path with a low time cost, so that the transport vehicle 2 can move from the current position to the designated position relatively quickly.

[0045] Furthermore, it's important to note that because transporter 2 must reduce its speed when traveling along curved tracks to avoid accidents like rollovers, the more curves a route contains, the longer it will take. Therefore, directly planning a route using the shortest path may result in a route with multiple curves, ultimately preventing transporter 2 from reaching its destination in the shortest possible time. In contrast, the transporter route planning method of the present invention calculates the travel time cost of each planned path and directs transporter 2 to the destination following the planned path with the lowest travel time cost, ensuring that transporter 2 can reach its destination relatively quickly.

[0046] As shown in Figure 2, in actual applications, the memory 3 may also store a static cost table 32. Static cost table 32 stores the minimum transit time corresponding to each road segment. The minimum transit time for each road segment refers to the shortest number of seconds it takes for a transport vehicle 2 to transit that road segment in operation. The method for establishing the minimum transit time for each road segment in static cost table 32 is not limited. For example, it may be pre-entered by relevant personnel, or the processing device 1 may collect the transit time of each transport vehicle 2 passing through each road segment and extract the minimum transit time for each road segment.

[0047] In a preferred embodiment, the processing device 1 may perform the following steps at every predetermined time interval:

[0048] A judgment step: judging whether there is at least one transport vehicle on each of the road sections;

[0049] If it is determined that there is no transport vehicle on at least one road section, the following steps are performed:

[0050] An automatic dynamic cost table updating step is performed: using the shortest transit seconds corresponding to the road segments without a transporter in a static cost table 32, all transit seconds for the road segments without a transporter in the dynamic cost table 31 are updated. This allows the average transit seconds corresponding to the road segments without a transporter in the dynamic cost table 31 to be updated with the shortest transit seconds corresponding to the road segments without a transporter in the static cost table 32. For example, Tables 4 and 5 below represent a portion of the dynamic cost table and a portion of the static cost table, respectively, before the automatic dynamic cost table updating step. Table 4 shows that the most recent time transporter 2 passed through road segment R01 was 2.8 seconds, while the previous time it took 3 seconds. The shortest transit seconds for road segment R01 was 2.5 seconds.

[0051] Table 4: Road section name The number of seconds it took to pass the previous time The number of seconds it took to pass the first two times Real-time average seconds R01 2.8 3 2.9 R02 1.5 1.3 1.4

[0052] Table 5: Road section name Minimum passing seconds R01 2.5 R02 1.0

[0053] Continuing from the above, assuming that when the processing device executes the above judgment step, it determines that there is no transport vehicle on section R01, the processing device will execute the automatic dynamic cost table update step, and then the dynamic cost table shown in Table 4 will be updated to the following Table 6, that is, the two passing seconds and real-time average seconds corresponding to section R01 in the dynamic cost table (Table 6) will be updated to 2.5 seconds (that is, the shortest passing seconds for section R01 in the static cost table).

[0054] Table 6: Road section name The number of seconds it took to pass the previous time The number of seconds it took to pass the first two times Real-time average seconds R01 2.5 2.5 2.5 R02 1.5 1.3 1.4

[0055] In one specific example, the dynamic cost table 31 may also store a last update time for each road segment. The processing device may read the last update time corresponding to each road segment at a predetermined interval. If the difference between the last update time and the current time exceeds the predetermined time, the processing device will execute the automatic dynamic cost table update step. This design allows the processing device to determine whether fewer than a predetermined number of transport vehicles 2 have passed through any road segment within the predetermined time. Of course, the processing device may also use different methods to make this determination.

[0056] Please refer to Figure 4, which shows a partial flowchart of the path planning method for a transport vehicle according to the present invention. In the embodiment where a static cost table 32 is stored in the memory, after any transport vehicle 2 passes through any road section in the operating state, the processing device may also perform the following steps:

[0057] A minimum number of seconds determination step S51: determining whether the instantaneous number of seconds taken by the transport vehicle 2 to pass through the road segment is less than the minimum number of seconds corresponding to the road segment in the static cost table 32;

[0058] If the processing device determines that the immediate passing seconds are greater than or equal to the shortest passing seconds, the minimum passing seconds determination step S51 is ended.

[0059] If the processing device determines that the instantaneous passing seconds are less than the shortest passing seconds, a static cost table updating step S52 is executed: the shortest passing seconds corresponding to the road section in the static cost table 32 is updated to the instantaneous passing seconds.

[0060] For example, when the track or the transport vehicle 2 in the factory has just completed maintenance, the speed of the transport vehicle 2 passing through each section may increase. By designing the above-mentioned minimum second determination step S51 and the static cost table update step S52, the shortest passing seconds for each section in the static cost table 32 can be kept in the latest state.

[0061] In practical applications, in the minimum seconds determination step S51, it is further determined whether the instantaneous passing seconds are greater than a preset minimum passing seconds. If the instantaneous passing seconds are greater than the preset minimum passing seconds, and less than the corresponding minimum passing seconds, the static cost table update step S52 is executed. The preset minimum passing seconds refers to the fastest possible number of seconds for the transport vehicle 2 to pass the road section in operation. If the instantaneous passing seconds are less than the preset minimum passing seconds, the instantaneous passing seconds are considered incorrect and should not be updated in the static cost table 32.

[0062] Please refer to FIG. 2 and FIG. 5 , which is a flow chart showing the inspection process of the path planning method for the transport vehicle of the present invention.

[0063] In actual applications, while transport vehicle 2 is traveling along the track, it may become blocked and stop at a certain road section for various reasons, i.e., transport vehicle 2 may become stuck in traffic on that road section. In this scenario, in the above embodiment, if transport vehicle 2 does not leave that road section, processing device 1 will not update the average transit seconds corresponding to that road section in dynamic cost table 31. Therefore, while transport vehicle 2 is stuck in traffic on a certain road section, processing device 1 may continuously plan dispatch routes for other transport vehicles 2 that include the congested road section, causing other transport vehicles 2 to also be stuck in the same congested road section.

[0064] The method by which processing device 1 determines whether transport vehicle 2 is stuck on a particular road section can be designed based on actual needs and is not limited herein. For example, processing device 1 may determine whether transport vehicle 2 is stuck based on its current speed, the total time that transport vehicle 2 has been at zero speed, and its current mission status (e.g., scheduled parking, scheduled transport, etc.).

[0065] It should be noted that, in practice, unless a transport vehicle 2 breaks down on a road section, even if the processing device 1 does not address the aforementioned traffic jam, the transport vehicle 2 can still successfully complete the transport operation; however, the transport vehicle 2 may take longer to complete the transport operation. In a typical transport vehicle 2 system, when any transport vehicle 2 breaks down, the processor 21 of that transport vehicle 2 will send fault information to the processing device 1. Therefore, when a transport vehicle 2 stops on a road section due to a fault, the processing device 1 will receive the fault information and issue an alert to the relevant personnel, prompting them to repair or remove the transport vehicle 2.

[0066] As shown in FIG6 , in one of the preferred embodiments of the present invention, the processing device 1 may execute a check procedure at a predetermined interval (e.g., 1 second, 0.5 seconds, etc.). The check procedure includes the following steps:

[0067] A transport vehicle state determination step S61: determining whether any transport vehicle 2 is in at least one preset state;

[0068] If it is determined that no transport vehicle 2 is in any of the preset states, the inspection procedure is terminated.

[0069] If it is determined that there are N transport vehicles 2 in at least one preset state, a weighted judgment procedure is executed one by one for the N transport vehicles 2. In other words, the processing device will execute the weighted judgment procedure N times.

[0070] The weighted judgment procedure comprises the following steps:

[0071] A calculation step S62: calculating a predicted number of seconds for the transport vehicle 2; the predicted number of seconds is the time it has taken for the transport vehicle 2 to enter the current section of the road, multiplied by a preset weighting value; the preset weighting value is greater than 0;

[0072] A second determination step S63: determining whether the predicted number of seconds is greater than the shortest passing time in a static cost table for the current road segment;

[0073] If the judgment is not greater than the shortest passing seconds, the weighted judgment procedure ends.

[0074] If it is determined to be greater than the minimum passing seconds, perform the following steps:

[0075] An updating step S64: updating the dynamic cost table to replace one of the passing seconds of the road segment in the dynamic cost table with the predicted seconds, and updating the average passing seconds of the road segment in the dynamic cost table accordingly.

[0076] One of the preset conditions is that when the transport vehicle 2 is not performing a transport operation or parking operation, the speed of the transport vehicle 2 is reduced to zero. Another of the preset conditions is that when the transport vehicle 2 is not performing a transport operation or parking operation, the sensor 22 of the transport vehicle 2 detects an obstacle in the direction of travel. Another of the preset conditions is that when the transport vehicle 2 is not performing a transport operation or parking operation, the processor 21 of the transport vehicle 2 issues a fault notification to the processing device.

[0077] For example, assuming that in the static cost table, the shortest passing seconds for section A is 20 seconds, the preset weight value is 8, the processing device executes the above-mentioned inspection procedure once per second, and the dynamic cost table contains 5 real-time passing seconds and average passing seconds corresponding to each section. Assume that the real-time passing seconds and average passing seconds corresponding to section A in the dynamic cost table are shown in Table 7 below.

[0078] Table 7: The latest instant passing seconds The number of seconds of the last instant pass The number of seconds for the first two instant passes The number of seconds for the first three instant passes The number of seconds for the first 4 instant passes Average passing seconds twenty one twenty two twenty two twenty three twenty three 22.2

[0079] If, three seconds after truck A enters road section A, its sensor 22 detects an obstacle in front of it (e.g., a stopped truck 2 or other object blocking its progress), and truck A's speed has dropped to zero, then truck A is stuck in traffic on road section A. After processing device 1 performs a check procedure, it determines that truck A meets two of the pre-determined conditions. Processing device 1 then performs a weighted judgment procedure. In calculation step S62, processing device 1 calculates a predicted transit time of 24 seconds. In second determination step S63, because the predicted transit time (24 seconds) is greater than the minimum transit time (20 seconds) for road section A, the processing device proceeds to update step S64. Ultimately, the instant transit time corresponding to road section A in the dynamic cost table is updated to 24 seconds, and the average transit time is updated to increase. That is to say, the value corresponding to Section A in the dynamic cost table will be updated as shown in Table 8 below. It can be clearly seen from Table 8 below that the average passing seconds of Section A will be updated from 22.2 seconds in Table 1 to 22.8 seconds. Therefore, before the transport truck A leaves Section A, it has already exceeded the average passing seconds in the dynamic cost table, reflecting the traffic congestion situation of Section A.

[0080] Table 8: The latest instant passing seconds The number of seconds of the last instant pass The number of seconds for the first two instant passes The number of seconds for the first three instant passes The number of seconds for the first 4 instant passes Average passing seconds twenty four twenty two twenty two twenty three twenty three 22.8

[0081] Because the processing device performs a check every second, if truck A's speed is still zero in the next second (i.e., four seconds after truck A enters road section A), the processing device will calculate a predicted speed of 32 seconds in step S63, and the dynamic cost table will be updated as shown in Table 9 below. As can be clearly seen in Table 9, the average transit time for road section A will be updated from 22.8 seconds in Table 2 to 24.6 seconds. In other words, truck A only stayed in road section A for one extra second, and the average transit time for road section A in the dynamic cost table has been updated from 22.8 seconds to 24.6 seconds.

[0082] Table 9: The latest instant passing seconds The number of seconds of the last instant pass The number of seconds for the first two instant passes The number of seconds for the first three instant passes The number of seconds for the first 4 instant passes Average passing seconds 32 twenty four twenty two twenty two twenty three 24.6

[0083] As mentioned above, 4 seconds after truck A enters section A, the average passing seconds corresponding to section A in the dynamic cost table will be updated from 22.2 seconds when truck A just enters section A to 24.6 seconds. As truck A stays on section A for longer, the average passing seconds corresponding to section A in the dynamic cost table will continue to rise.

[0084] In summary, by designing the processing device 1 to execute a check program once every preset time interval, the dynamic cost table can more quickly reflect any road section where traffic congestion occurs. In this way, when the processing device 1 executes the path planning step, it can correctly plan a planned path with the lowest or relatively low travel time cost.

[0085] Please refer to Figures 1 and 6 . Figure 6 shows a schematic diagram of another embodiment of a transport vehicle control system according to the present invention. After processing device 1 transmits movement information 11 to transport vehicle 2, if processing device 1 determines, based on the position data transmitted back by transport vehicle 2, that transport vehicle 2 is at a predetermined position (e.g., a fork position), processing device 1 will re-execute the transport vehicle path planning method. The predetermined position refers to the position immediately before at least two tracks intersect. After transport vehicle 2 passes the predetermined position, it can proceed along one of the tracks.

[0086] As shown in Figure 1, assume that processing device 1, in the scenario shown in Figure 1, determines that the time cost of moving along path P1 is higher than the time cost of moving along path P2. Therefore, processing device 1 controls transport vehicle 2B to move along planned path P2 to workstation X2. During the process of transport vehicle 2 moving based on the aforementioned movement information, if processing device 1 determines that transport vehicle 2B is at the preset position shown in Figure 6, processing device 1 will re-execute the transport vehicle path planning method to re-plan a path for transport vehicle 2 to move from its current position to workstation X2. In other words, in the scenario shown in Figure 6, if processing device 1 determines that the time cost of continuing to move the transport vehicle along road segments R11, R12-R18 is lower after re-execution of the transport vehicle path planning method, processing device 1 will control transport vehicle 2 to move along path P3, which includes road segments R11, R12-R18.

[0087] It should be noted that, in practice, the processing device 1 may determine whether it is necessary to re-perform the path planning method for any transport vehicle at a preset time interval, that is, based on the position and status of each transport vehicle.

[0088] As described above, by allowing the processing device to re-plan the path of the transport vehicle when it is determined that the transport vehicle is at a preset position, the transport vehicle 2 can basically move along the path that takes the least time before moving to the destination.

[0089] In summary, the path planning method and control system of the transport vehicle of the present invention, through the design of dynamic cost table reading steps, path planning steps and vehicle dispatching steps, can plan a vehicle dispatching path with the lowest moving time cost, so that the transport can spend the least time and move to the destination.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Therefore, all equivalent technical changes made using the description and drawings of the present invention are included in the protection scope of the present invention.

[0091] 100: Truck control system 1: Processing device 11: Mobile Information 2: Truck 21: Processor 211: Endpoint Information 212: Status Information 2121: Obstacle Information 2122: Fault information 22: Sensor 23: Reader 231: Location information 2A: Truck 2B: Truck 3: Storage 31: Dynamic Cost Table 32: Static Cost Table X1: Workstation X2: Workstation P1: Planning the path P2: Planning Path P3: Planning Path R01, R02, R03, R04, R05, R06, R07, R08, R09, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21: road sections 200:Material handling control system 201: Transport Information S11: Dynamic cost table reading step S12: Path planning step S13: Vehicle dispatching steps S51: Minimum seconds judgment step S52: Static cost table update step S61: Truck status determination step S62: Calculation steps S63: Seconds judgment step S64: Update Steps

Claims

1. A path planning method for a transport vehicle, suitable for execution by a processing device of a transport vehicle control system, wherein the processing device, after receiving transport information, can execute the path planning method to determine multiple road segments traversed by controlling the transport vehicle to move from a current position to a destination; the transport information includes destination data; the path planning method for the transport vehicle includes the following steps: a dynamic cost table reading step: reading a dynamic cost table to obtain an average transit time for each road segment; the dynamic cost table contains N transit times corresponding to each road segment; the average transit time is the total average of the N transit times corresponding to the road segment in the dynamic cost table; wherein, N is a positive integer greater than 2; the dynamic cost table is stored in a memory of the transport vehicle control system; A path planning step: Based on the current location, destination information, and dynamic cost table, a path planning algorithm is used to generate multiple planned paths; A dispatching step: Mobility information is transmitted to the transport vehicle to control it to move from the current location to the destination along a dispatching path; the dispatching path is the planned path with the lowest mobility time cost; the mobility time cost is the sum of the average transit times corresponding to all road segments included in the planned path; wherein, when each transport vehicle passes through any road segment in a running state, the processing device replaces one of the corresponding transit times in the dynamic cost table with the instantaneous transit times spent by the transport vehicle through the road segment; when the transport vehicle passes through the road segment in the running state, the transport vehicle does not perform a transport operation or a parking operation in the road segment based on any mobility information; wherein, the processing device executes the following steps once every preset time interval: A transport vehicle status determination step: Determine whether any of the transport vehicles is in at least one preset state; if it is determined that a transport vehicle is in at least one preset state, then perform the following steps one by one for all transport vehicles in the preset states: A calculation step: Calculate a predicted number of seconds for the transport vehicle; the predicted number of seconds is the time already spent by the transport vehicle entering the current road segment, multiplied by a preset weighting value; the preset weighting value is greater than 0; A number of seconds determination step: Determine whether the predicted number of seconds is greater than a minimum transit time for the current road segment in a static cost table; if it is determined that it is greater than the minimum transit time, then perform the following steps: An update step: Update the dynamic cost table to replace one of the transit times for the road segment in the dynamic cost table with the predicted number of seconds, and update the average transit time for the road segment in the dynamic cost table accordingly.

2. The path planning method for the transport vehicle as described in claim 1, wherein, One of the preset states is: when the transport vehicle is not performing the transport operation or the parking operation, the speed of the transport vehicle is reduced to 0.

3. The path planning method for the transport vehicle as described in claim 1, wherein, One of the preset states is: when the transport vehicle is not performing the transport operation or the parking operation, a sensor of the transport vehicle detects an obstacle in the direction of travel.

4. The path planning method for the transport vehicle as described in claim 1, wherein, One of the preset states is: when the transport vehicle is not performing the transport operation or the parking operation, a processor of the transport vehicle sends a fault notification to the processing device.

5. The path planning method for the transport vehicle as described in claim 1, wherein, If less than a preset number of transport vehicles pass through any given road segment within the preset time, the processing device will execute an automatic dynamic cost table update step: using the shortest passing time corresponding to the road segment in the static cost table, update all the passing time counts for the road segment in the dynamic cost table; wherein, the shortest passing time count corresponding to each road segment in the static cost table refers to the shortest number of seconds taken by the transport vehicle to pass through the road segment in the operating state; the static cost table is stored in the storage.

6. The path planning method for the transport vehicle as described in claim 5, wherein, When any of the transport vehicles passes through any of the road segments in the operating state, the processing device will perform a minimum time determination step: determine whether the instantaneous passage time spent by the transport vehicle to pass through the road segment is less than the shortest passage time corresponding to the road segment in the static cost table; if it is determined that the instantaneous passage time is less than the shortest passage time, then perform a static cost table update step: update the shortest passage time corresponding to the road segment in the static cost table to the instantaneous passage time.

7. The path planning method for the transport vehicle as described in claim 6, wherein, In the minimum number of seconds determination step, it is also determined whether the instantaneous passing time is greater than a preset minimum limit number of seconds; if the instantaneous passing time is greater than the preset minimum limit number of seconds and the instantaneous passing time is less than the corresponding shortest passing time, then the static cost table update step is executed.

8. The path planning method for the transport vehicle as described in claim 1, wherein, Multiple marker units are arranged around each track of the transport vehicle system. A reader on each transport vehicle can read position data from the marker units, and the transport vehicle can transmit the position data back to the processing device. After the processing device transmits the movement information to the transport vehicle, when the processing device determines that the transport vehicle is located at a fork in the road based on the position data transmitted back by the transport vehicle, the processing device will execute the path planning method of the transport vehicle again. The fork in the road refers to the position in the direction of travel of the transport vehicle before at least two tracks intersect. When the transport vehicle passes through the fork in the road, it can move along one of the tracks.

9. A transport vehicle control system, comprising: a plurality of tracks, with at least one workstation arranged around a portion of the tracks; a plurality of transport vehicles, each of the transport vehicles capable of moving along the tracks to any one of the workstations to perform a transport operation; a processing device communicatively connected to each of the transport vehicles; the processing device, upon receiving transport information, executing a path planning method for a transport vehicle to determine the route through which one of the transport vehicles will move from a current position to a destination; the transport information includes destination data; wherein... The path planning method for the transport vehicle includes the following steps: A dynamic cost table reading step: reading a dynamic cost table to obtain an average transit time for each road segment; the dynamic cost table contains N transit times corresponding to each road segment, and the average transit time is the total average of the N transit times corresponding to the road segment in the dynamic cost table; where N is a positive integer greater than 2; the dynamic cost table is stored in a memory of the transport vehicle control system; A path planning step: generating multiple planned paths using a path planning algorithm based on the current location, the destination information, and the dynamic cost table; A dispatching step: transmitting movement information to the transport vehicle to control the transport vehicle to move from the current location to the destination along a dispatching path; the dispatching path is the planned path with the lowest movement time cost; the movement time cost is the sum of the average transit times corresponding to all road segments included in the planned path; In this process, when each of the transport vehicles passes through any of the road segments in an operational state, the processing device replaces one of the corresponding passage time entries for that road segment in the dynamic cost table with the instantaneous passage time spent by the transport vehicle through the road segment. When the transport vehicle passes through the road segment in the operational state, it does not perform a transport operation or a parking operation in the road segment based on any transport information. The processing device executes the following steps at preset time intervals: A transport vehicle status determination step: determining whether any of the transport vehicles is in at least one preset state; If it is determined that a transport vehicle is in at least one preset state, then for each transport vehicle in the preset state, the following steps are executed sequentially: A calculation step: calculating a predicted number of seconds for the transport vehicle; the predicted number of seconds is the time already spent by the transport vehicle entering the current road segment multiplied by a preset weighting value; the preset weighting value is greater than 0; A second count determination step: determining whether the predicted number of seconds is greater than the shortest passage time for the current road segment in a static cost table. If the value is greater than the minimum transit time, the following steps are performed:

1. Update step: Update the dynamic cost table to replace the transit time of the road segment in one of the entries in the dynamic cost table with the predicted transit time.

10. The transport vehicle control system as described in claim 9, wherein, One of the preset states is: when the transport vehicle is not performing the transport operation or the parking operation, the speed of the transport vehicle is reduced to 0.

11. The transport vehicle control system as described in claim 9, wherein, One of the preset states is: when the transport vehicle is not performing the transport operation or the parking operation, a sensor of the transport vehicle detects an obstacle in the direction of travel.

12. The transport vehicle control system as described in claim 9, wherein, One of the preset states is: when the transport vehicle is not performing the transport operation or the parking operation, a processor of the transport vehicle sends a fault notification to the processing device.

13. The transport vehicle control system as described in claim 9, wherein, The processing device will perform the following steps at preset intervals: a segment vehicle judgment step: determining whether there is at least one transport vehicle in each segment; if it is determined that there is no transport vehicle in at least one segment, then the following steps will be performed: an automatic dynamic cost table update step: using the shortest passage time corresponding to the segment without the transport vehicle in the static cost table, updating all passage time values ​​of the segment in the dynamic cost table; wherein, the shortest passage time value corresponding to each segment in the static cost table refers to the shortest number of seconds taken by the transport vehicle to pass through the segment in the operating state; the static cost table is stored in the storage.

14. The transport vehicle control system as described in claim 13, wherein, When any of the transport vehicles passes through any of the road segments in the operating state, the processing device will perform a minimum time determination step: determine whether the instantaneous passage time spent by the transport vehicle to pass through the road segment is less than the shortest passage time corresponding to the road segment in the static cost table; if it is determined that the instantaneous passage time is less than the shortest passage time, then perform a static cost table update step: update the shortest passage time corresponding to the road segment in the static cost table to the instantaneous passage time.

15. The transport vehicle control system as described in claim 14, wherein, In the minimum number of seconds determination step, it is also determined whether the instantaneous passing time is greater than a preset minimum limit number of seconds; if the instantaneous passing time is greater than the preset minimum limit number of seconds and the instantaneous passing time is less than the corresponding shortest passing time, then the static cost table update step is executed.

16. The transport vehicle control system as described in claim 9, wherein, Each track is surrounded by multiple marker units. Each transport vehicle has a reader that can read position data from the marker units, and the transport vehicle can transmit the position data back to the processing device. After the processing device transmits the movement information to the transport vehicle, when the processing device determines that the transport vehicle is located at a preset position based on the position data transmitted back by the transport vehicle, the processing device will execute the path planning method of the transport vehicle again. The preset position refers to the position before at least two tracks intersect, and when the transport vehicle passes the preset position, the transport vehicle can move along one of the tracks.

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