Autonomous vehicle, speed determination system, and speed determination method

Abstract

The present invention provides an autonomous vehicle, a speed determination system, and a speed determination method that reduce memory usage when determining driving speed or acceleration, and improve the accuracy of values ​​representing driving speed or acceleration while reducing the amount of computation. [Solution] The forklift 1, which is an autonomous driving vehicle, is equipped with a memory 16 which is a storage unit, and an ECU 17 which also serves as a speed range determination unit, a speed determination unit, and a driving control unit. The memory 16 stores speed constraint information and acceleration constraint information. Based on the speed constraint information, acceleration constraint information and information on the final speed, the ECU 17 sequentially determines the upper limit of the speed range at each of the multiple discrete points from the final point side, and based on the information on the starting speed and the upper limit of the speed range at each of the multiple discrete points, it sequentially determines the driving speed at each of the multiple discrete points from the starting point side, and controls the driving of the vehicle body 1A based on the speed information related to the determined driving speed.

Description

[Technical Field]

[0001] The present invention relates to an autonomous vehicle that travels along a predetermined route, as well as a speed determination system and a speed determination method for determining the vehicle's travel speed or acceleration. [Background technology]

[0002] Automated guided vehicles (AGVs) and unmanned forklifts are known as autonomous vehicles that perform cargo handling, such as transporting goods, and travel along predetermined or dynamically generated predetermined routes in a specific environment (e.g., inside a warehouse or factory). To improve the efficiency of cargo handling operations, it is desirable to shorten the travel time of autonomous vehicles, and it is necessary to determine the travel speed of the autonomous vehicle that minimizes travel time before starting travel. One known method for determining the travel speed is dynamic programming, which divides the problem into multiple subproblems, memoizes the solutions of the subproblems, and solves the problem using the memoized solutions.

[0003] Patent Document 1 describes an information processing device that applies dynamic programming based on a discretized travel path of a moving object to its destination and performs the task of minimizing the time it takes to reach the destination. This information processing device comprises a generation unit that generates the state of the moving object at the next position from the state of the moving object at each position obtained by discretizing the travel path of the moving object, and an optimization unit that optimizes the usage state of the drive means of the moving object based on the state of the moving object at each position generated by the generation unit. The generation unit generates the state of the moving object as, for example, the time, the speed of the moving object, and the remaining battery level, under the constraints of each position. The optimization unit selects, for example, the state that minimizes the time it takes to reach the destination from among the multiple states of the moving object at the destination generated by the generation unit as the optimal state, and identifies the usage state of the drive means corresponding to the state at each position leading to the selected state as the optimal usage state.

[0004] Furthermore, the information processing device described in Patent Document 1 identifies the optimal driving method for each position by applying a dynamic programming method that generates and optimizes the possible states of the moving body at each discretized position of the movement path. Specifically, if the generation unit determines that one of the multiple states of the moving body at the next position is equal to or inferior to any of the other states in terms of a predetermined set of parameters (elements), it prunes (thins out) that state. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6324157 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in configurations that optimize driving speed using dynamic programming, the solution to a subproblem is memoized, which leads to a problem where memory usage increases as the number of states increases. Although the number of states can be reduced by pruning, as described in Patent Document 1, this may not sufficiently reduce memory usage. Furthermore, there was a need to improve the accuracy of the value representing the driving speed while reducing the computational complexity.

[0007] The present invention has been made in view of the above circumstances, and aims to provide an autonomous vehicle, a speed determination system, and a speed determination method that can reduce the amount of memory used when determining the driving speed or acceleration, and improve the accuracy of the value representing the driving speed or acceleration while reducing the amount of computation. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides an autonomous driving vehicle that travels along a predetermined path from a starting point to an ending point located on the path, and is characterized by comprising: a storage unit that stores speed constraint information relating to speed constraints when passing through a plurality of discrete points located on the path from the starting point to the ending point, and acceleration constraint information relating to acceleration constraints at the plurality of discrete points; a speed range determination unit that determines the upper limit of the speed range at each of the plurality of discrete points in order from the ending point side based on the speed constraint information, the acceleration constraint information, and information relating to the ending speed which is the driving speed at the ending point; a speed determination unit that determines the driving speed or acceleration at each of the plurality of discrete points in order from the starting point side based on the acceleration constraint information, information relating to the starting speed which is the driving speed at the starting point, and the upper limit of the speed range at each of the plurality of discrete points determined by the speed range determination unit; and a driving control unit that controls driving based on the speed information relating to the driving speed or acceleration determined by the speed determination unit.

[0009] Furthermore, it is preferable that the speed range determination unit calculates an upper limit of the first speed range based on the acceleration constraint information, the information regarding the endpoint speed, and the information regarding the intervals between the plurality of discrete points, and then determines the smaller of the upper limit of the first speed range and the upper limit of the second speed range obtained from the speed constraint information as the upper limit of the speed range.

[0010] Furthermore, it is preferable that the speed determination unit calculates the upper limit of the first acceleration range based on the information regarding the starting speed, the information regarding the intervals between the plurality of discrete points, and the upper limit of the speed range at each of the plurality of discrete points determined by the speed range determination unit, and determines the smaller of the upper limit of the first acceleration range and the upper limit of the second acceleration range obtained from the acceleration constraint information as the upper limit of the acceleration range, and calculates and determines the travel speed when passing through each of the plurality of discrete points based on the upper limit of the acceleration range, the information regarding the starting speed, and the information regarding the intervals between the plurality of discrete points.

[0011] Furthermore, in order to solve the above problems, the speed determination system of the present invention is a speed determination system for determining the driving speed or acceleration of an automated driving vehicle that travels along a predetermined path from a starting point to an ending point located on the path, and is characterized by comprising: a storage unit that stores speed constraint information relating to speed constraints when passing through a plurality of discrete points located on the path from the starting point to the ending point, and acceleration constraint information relating to acceleration constraints at the plurality of discrete points; a speed range determination unit that determines the upper limit of the speed range at each of the plurality of discrete points in order from the ending point side based on the speed constraint information, the acceleration constraint information, and information relating to the ending speed which is the driving speed at the ending point; and a speed determination unit that determines the driving speed or acceleration at each of the plurality of discrete points in order from the starting point side based on the acceleration constraint information, information relating to the starting speed which is the driving speed at the starting point, and the upper limit of the speed range at each of the plurality of discrete points determined by the speed range determination unit.

[0012] Furthermore, in order to solve the above problems, the present invention provides a speed determination method for determining the driving speed or acceleration of an automated driving vehicle traveling along a predetermined path from a starting point to an ending point located on the path, characterized by comprising: an information acquisition step of acquiring speed constraint information relating to speed constraints when passing through a plurality of discrete points located on the path from the starting point to the ending point, and acceleration constraint information relating to acceleration constraints at the plurality of discrete points; a speed range determination step of determining the upper limit of the speed range at each of the plurality of discrete points in order from the ending point side, based on the speed constraint information, the acceleration constraint information, and information relating to the ending speed, which is the driving speed at the ending point; and a speed determination step of determining the driving speed or acceleration at each of the plurality of discrete points in order from the starting point side, based on the acceleration constraint information, information relating to the starting speed, which is the driving speed at the starting point, and the upper limit of the speed range at each of the plurality of discrete points determined in the speed range determination step. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an autonomous vehicle, a speed determination system, and a speed determination method that can reduce the amount of memory used when determining the driving speed or acceleration, and improve the accuracy of the value representing the driving speed or acceleration while reducing the amount of computation. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of an autonomous vehicle relating to one embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating the information used in the speed determination method according to the same embodiment. [Figure 3] This flowchart shows the flow of the speed determination process according to the same embodiment. [Figure 4] This flowchart shows the flow of the speed determination process according to the same embodiment. [Figure 5] This is a schematic diagram of the speed determination system related to a modified example. [Modes for carrying out the invention]

[0015] An autonomous vehicle according to one embodiment of the present invention will be described with reference to the drawings. In this specification, the subscript "N" and the "N" contained in parentheses represent, for example, any natural number greater than or equal to 6.

[0016] As shown in Figure 1, the autonomous vehicle according to this embodiment is a forklift 1, which is an AGF (Automated Guided Forklift) that transports cargo without a driver. The forklift 1 of this embodiment is equipped with a speed determination system consisting of a memory 16 and an ECU 17, which will be described later.

[0017] Forklift 1 travels along a predetermined path p (see Figure 2) from a discrete point S1 (see Figure 2), which is the starting point, located on path p, to a discrete point S, which is the ending point. NIt travels to (see Figure 2). The forklift 1 consists of a vehicle body 1A that can travel straight in the forward / backward direction X, and a cargo handling device 1B that performs cargo handling.

[0018] The forklift 1 comprises a vehicle body 1A consisting of wheels 11, a drive unit 12, a steering unit 13, a laser scanner 14, an estimation device 15, a memory 16, and an ECU (Electronic Control Unit) 17.

[0019] Wheel 11 is a drive wheel that transmits power from the drive unit 12 to the road surface, and is also a steering wheel whose steering angle (direction) can be changed. In other words, wheel 11 serves as both a steering wheel and a drive wheel.

[0020] The drive unit 12 is a drive device that drives the wheels 11. The drive unit 12 consists of a travel motor, which is an electric motor that transmits power to the wheels 11, and a drive circuit for driving the travel motor.

[0021] The steering unit 13 is a steering device that controls the steering angle of the wheels 11. The steering unit 13 consists of a support mechanism that supports the wheels 11, a steering motor which is an electric motor that transmits power to the support mechanism, and a drive circuit for driving the steering motor.

[0022] The laser scanner 14 and estimation device 15 are position detection units for detecting the position of the forklift 1 (i.e., the vehicle itself). The laser scanner 14 is a LiDAR (Light Detection And Ranging) sensor that projects laser light around the forklift 1 and receives the reflected light to acquire environmental information around the forklift 1.

[0023] The estimation device 15 is a device that estimates the position of the forklift 1 based on environmental information acquired by the laser scanner 14. The estimation device 15 performs SLAM (Simultaneous Localization And Mapping) processing, which simultaneously creates an environmental map of the area around the forklift 1 and estimates the position of the forklift 1 on the environmental map.

[0024] Memory 16 is a memory unit that stores the program executed by ECU 17 and information necessary for the execution of that program. Specifically, memory 16 pre-stores discrete point interval information, speed constraint information, acceleration constraint information, and specified speed information so that ECU 17 can perform the speed determination process described later. Memory 16 also stores the speed information generated in the speed determination process described later.

[0025] The ECU 17 functions as a speed range determination unit and a speed determination unit by performing the speed determination process described later. Furthermore, the ECU 17 functions as a driving control unit by controlling the drive unit 12.

[0026] Specifically, ECU17 handles velocity constraint information, acceleration constraint information, and endpoint (discrete point S). N Based on information regarding the final speed, which is the speed at which the vehicle travels, multiple discrete points S1~S N (See Figure 2) The upper and lower limits of the speed range at each point are determined sequentially from the endpoint. In this way, the ECU 17 functions as a speed range determination unit that determines a speed range that satisfies predetermined constraints regarding speed and acceleration.

[0027] Furthermore, the ECU17 receives acceleration constraint information, information on the starting point speed which is the speed at the starting point (discrete point S1), and a speed range determination unit which determines multiple discrete points S1~S N Based on the upper limit of the velocity range in each of the multiple discrete points S1~S N-1 Acceleration at each of the multiple discrete points S1~S NThe traveling speed at each of these is determined in order from the starting point side. Thus, the ECU 17 functions as a speed determination unit that determines the traveling speed and acceleration that minimize the traveling time.

[0028] When determining the speed range and traveling speed, the ECU 17 uses the following mathematical formula (1) showing the relationship between the traveling speeds V(i) and V(i + 1) when passing through adjacent discrete points S i , S i+1 . In the following mathematical formula (1), the value of the working variable i described later is substituted for the subscript and the "i" included in the parentheses. The mathematical formula (1) is obtained by solving the initial value problem of an ordinary differential equation assuming that the control input to the drive unit 12 is constant when the forklift 1 travels from the discrete point S i to the discrete point S i+1 . In the mathematical formula (1), "a(i)" represents the acceleration at the discrete point S i , and "δ i " represents the interval between the discrete points S i , S i+1 .

Number

[0029] Further, the ECU 17 controls the drive unit 12 so that the vehicle body 1A travels at the determined traveling speed or acceleration based on the traveling speed information regarding the traveling speed or acceleration determined as the speed determination unit. Thus, the ECU 17 functions as a traveling control unit that controls the traveling of the vehicle body 1A. Also, the ECU 17 controls the steering unit 13 so that the vehicle body 1A travels along the path p.

[0030] Further, as a configuration of the cargo handling device 1B, the forklift F includes a fork 18 constituted by a pair of left and right claws 18A and 18B, and a lift device 19 that raises and lowers (moves in the vertical direction) the fork 18.

[0031] Referring to FIG. 2, the discrete point interval information, speed constraint information, acceleration constraint information, and designated speed information used in the speed determination process will be described.

[0032] In this embodiment, the forklift 1 starts traveling from the starting point (discrete point S1) to discrete points S2~S N-1 Passing through to the endpoint (discrete point S) N The system is configured to stop at ), and the discrete point interval information is a set of discrete points S1~S located on the path p from the starting point to the ending point. N interval δ1~δ N-1 This is information regarding [the topic].

[0033] Velocity constraint information is distributed between discrete points S1 and S N This information concerns the speed constraints when passing through the discrete points S1 to S. Specifically, the speed constraint information includes the speed constraints when forklift 1 passes through the discrete points S1 to S. N Upper limit of speed when passing through max (1) ~v max Information regarding (N), and forklift 1 at discrete points S1~S N Lower limit of velocity v when passing through min (1) ~v min This contains information about (N).

[0034] Acceleration constraint information is available at discrete points S1~S N This is information regarding the acceleration constraints at the following location. Specifically, the acceleration constraint information includes the following: Forklift 1 moves between discrete points S1 and S N Upper limit of acceleration a when passing through max (1) ~a max Information regarding (N), and forklift 1 at discrete points S1~S N Lower limit of acceleration a when passing through min (1) ~a min This contains information about (N).

[0035] The specified speed information is the starting speed v, which is the speed at the discrete point S1, which is the starting point. start Information regarding the endpoint, and the discrete point S. N The final speed v is the speed at which the train travels. end This includes information regarding the following. In this embodiment, the forklift 1 starts traveling from discrete point S1 to discrete point SN To stop the vehicle, the starting speed v start and final speed v end It is 0.

[0036] The flow of the speed determination process by the ECU 17 will be explained with reference to Figures 3 and 4. In this embodiment, the speed determination process is performed before the forklift 1 starts moving. First, the ECU 17 obtains discrete point interval information, velocity constraint information, acceleration constraint information, and specified velocity information from the memory 16 (information acquisition step S1).

[0037] Next, the ECU17 performs an initialization process (initialization step S2) in order to perform steps S3 to S8 described later. Specifically, in step S2, the ECU17 performs an initialization process (initialization step S2) to obtain the final speed v in step S1. end At discrete point S N Upper limit W of the velocity range W(N) max (N) and lower limit W min Set as (N), and then substitute (N-1) into the working variable i. In this embodiment, the final velocity v end Since it is 0, the upper limit W of the speed range (N) max (N) and lower limit W min (N) is set to 0.

[0038] Next, ECU17 will determine the discrete point S i+1 Upper limit W of the velocity range W(i+1) max (i+1) and discrete point S obtained in step S1. i Lower limit of acceleration a min (i) and discrete point S obtained in step S1 i ,S i+1 interval δ i Based on this, discrete point S i Upper limit of the speed range V max (i) is calculated (first speed range upper limit calculation step S3). Specifically, in step S3, the ECU17 calculates the upper limit V according to the following formula (2). max (i) is calculated. Below, the upper limit V is calculated in step S3. max(i) "Upper limit V in the first speed range" max (i)"

number

[0039] Furthermore, ECU17 is a discrete point S i+1 Lower limit W of velocity range W(i+1) min (i+1) and discrete point S obtained in step S1. i Upper limit of acceleration a max (i) and discrete point S obtained in step S1 i ,S i+1 interval δ i Based on this, discrete point S i Lower limit of the velocity range V min (i) is calculated (first speed range lower limit calculation step S4). Specifically, in step S4, the ECU17 calculates the lower limit V according to the following formula (3). min (i) is calculated. Note that "(W min (i+1)) 2 -2 × a max (i) × δ i When " is less than 0, the lower bound V min (i) is set to 0. The lower limit V is calculated in step S4 below. min (i) “Lower limit V in the first speed range” min (i)"

number

[0040] Next, ECU17 retrieves the discrete point S obtained in step S1. i Upper limit of speed v max (i) “Upper limit of the second speed range v max (i) The upper limit V of the first speed range calculated in step S3 max (i) and the upper limit of the second speed range v max (i) Based on the above, the upper limit W of the velocity range W(i) max (i) is determined (speed range upper limit determination step S5). Specifically, in step S5, the ECU 17 determines the upper limit V of the first speed range.max (i) and the upper limit v of the second speed range max Select the smaller of (i) as the upper limit W of the speed range W(i). max That is, the upper limit W of the speed range W(i) max (i) is defined by the following formula (4).

Equation

[0041] Also, the ECU 17 uses the lower limit v of the speed at the discrete point S obtained in step S1 i (i) as the "lower limit v of the second speed range min (i)", and based on the lower limit V of the first speed range calculated in step S4 min (i) and the lower limit v of the second speed range min (i), determine the lower limit W of the speed range W(i) (speed range lower limit determination step S6). Specifically, in step S6, the ECU 17 uses the larger of the lower limit V of the first speed range min (i) and the lower limit v of the second speed range min (i) as the lower limit W of the speed range W(i). min (i) and the lower limit v of the second speed range min (i) as the lower limit W of the speed range W(i). That is, the lower limit W of the speed range W(i) min (i) is determined as follows. min (i) is defined by the following formula (5). Note that the lower limit W of the speed range W(i) min (i) can be used to confirm that the acceleration range A(i - 1) described later is not an empty set (that is, when accelerating at the upper limit A of the acceleration range A(i - 1) at the discrete point S i-1 (i - 1), the traveling speed at the discrete point S max (i - 1) is not less than the lower limit W of the speed range W(i) i (i)). min (i)

Equation

[0042] Next, the ECU 17 subtracts 1 from the working variable i (decrement step S7) and determines whether the working variable i is 1 or greater (loop termination determination step S8). If the working variable i is 1 or greater (step S8: YES), the ECU 17 repeats steps S3 onwards. In this way, steps S3 to S6 are repeated, and the upper limit W of the speed range W(N-1) to W(1) is set. max (N-1)~W max (1) and lower limit W min (N-1)~W min (1) is determined.

[0043] As described above, steps S2 to S6 involve speed constraint information, acceleration constraint information, and endpoint velocity v end Based on the information, the upper limit W of the speed range W(1)~W(N) max (1) ~ W max (N) and lower limit W min (1) ~ W min This constitutes a speed range determination step in which (N) is determined sequentially from the terminal side.

[0044] If the working variable i becomes less than 1 (step S8: NO), the ECU17 performs initialization processing in order to perform steps S10 to S14 described later (initialization step S9). Specifically, in step S9, the ECU17 uses the starting velocity v obtained in step S1. start This is set as the travel speed V(1) at discrete point S1, and then 1 is substituted for the working variable i. In this embodiment, the starting point speed v start Since it is 0, the travel speed V(1) is set to 0.

[0045] Next, ECU17 will determine the discrete point S i The driving speed V(i) at the point and the discrete point S obtained in step S1. i ,S i+1 interval δ i And the discrete point S determined in step S5 i+1 Upper limit W of the velocity range W(i+1) max Based on (i+1), discrete point S i Upper limit α of acceleration in max(i) is calculated (first acceleration range upper limit calculation step S10). Specifically, in step S10, the ECU17 calculates the upper limit α according to the following formula (6). max (i) is calculated. The upper limit α is calculated in step S10 below. max (i) "Upper limit α of the first acceleration range" max (i)"

number

[0046] Next, ECU17 retrieves the discrete point S obtained in step S1. i Upper limit of acceleration a max (i) "Upper limit of the second acceleration range a max (i) The upper limit α of the first acceleration range calculated in step S10 max (i) and the upper limit a of the second acceleration range max (i) Based on this, the upper limit A of acceleration range A(i) max (i) is determined (acceleration range upper limit determination step S11). Specifically, in step S11, the ECU 17 determines the upper limit α of the first acceleration range. max (i) and upper limit a of the second acceleration range max The smaller of (i) is the upper limit A of acceleration range A(i). max (i) is determined as follows: That is, the upper limit A of the acceleration range A(i) max (i) is defined by the following formula (7).

number

[0047] Next, the ECU17 determines the upper limit A of the acceleration range A(i) determined in step S11. max (i) and discrete point S i The driving speed V(i) at the point and the discrete point S obtained in step S1. i ,S i+1 interval δ i Based on this, discrete point S i+1The driving speed V(i+1) at the discrete point S is calculated and determined (driving speed calculation step S12). Specifically, in step S12, the ECU17 calculates the driving speed V(i+1) at the discrete point S according to the following formula (8). i+1 Calculate the travel speed V(i+1) when passing through [the specified point].

number

[0048] Next, ECU17 increments the working variable i by 1 (increment step S13) and determines whether the working variable i is less than or equal to (N-1) (loop termination determination step S14). If the working variable i is less than or equal to (N-1) (step S14: YES), ECU17 repeats steps S10 onwards. In this way, steps S10 to S12 are repeated, and discrete points S1 to S N-1 The upper limit A of the acceleration range A(1) to A(N-1) is the acceleration in this region. max (1)~A max (N-1) is determined, and discrete points S2~S N The travel speeds V(2) to V(N) are determined.

[0049] As described above, steps S9 to S12 involve acceleration constraint information and starting velocity v start Information regarding and multiple discrete points S1-S determined in the velocity range determination step (steps S2-S6) N Upper limit W of the velocity range W(1)~W(N) in each of these max (1) ~ W max Based on (N), multiple discrete points S1~S N-1 Acceleration at each of the multiple discrete points S2~S N This constitutes a speed determination step in which the travel speeds V(2) to V(N) at each of these points are determined sequentially from the starting point.

[0050] Furthermore, when the working variable i is N-1, in step S12, instead of calculating the travel speed V(N) according to formula (8), the final speed v obtained in step S1 is used. end at discrete point S NThe driving speed V(N) may be set as the driving speed in this case.

[0051] If the working variable i exceeds (N-1) (step S14: NO), the ECU 17 terminates the speed determination process. In this way, the speed determination process generates speed information related to the travel speeds V(1) to V(N), and after the speed determination process, the speed information is stored in memory 16. Based on the speed information, the ECU 17 determines the travel speed of the vehicle body 1A (i.e., the travel speed of the forklift 1) between discrete points S1 and S N The movement of the vehicle body 1A is controlled so that the travel speed is V(1) to V(N) in each of these cases.

[0052] In this embodiment, the following effects can be obtained. (1) The forklift 1 (autonomous vehicle) is equipped with a memory 16 (storage unit) and an ECU 17 (speed range determination unit, speed determination unit, driving control unit), and the ECU 17 controls discrete points S1~S N Upper limit W of the velocity range W(1)~W(N) in each of these max (1) ~ W max (N) and lower limit W min (1) ~ W min (N) to the endpoint (discrete point S) N The upper limit of the speed range W(1) to W(N) is determined in order from the ) side. max (1) ~ W max Based on (N), etc., discrete points S1~S N-1 Acceleration and discrete points S1~S at each of these points NThe travel speeds V(1) to V(N) at each point are determined sequentially from the starting point (discrete point S1). That is, the speed ranges W(N) to W(1) are determined sequentially from the endpoint based on the conditions related to travel speed, and the acceleration and travel speeds V(1) to V(N) are determined sequentially from the starting point based on the conditions related to travel speed that include the speed ranges W(1) to W(N). With this configuration, it is possible to reduce the amount of memory used (computational resources) to determine the travel speeds V(1) to V(N) and acceleration compared to a configuration that optimizes travel speed using dynamic programming with memoization. In addition, since it is not necessary to discretize the travel speed and acceleration, it is possible to improve the accuracy of the values ​​representing the travel speeds V(1) to V(N) and acceleration while reducing the amount of computation.

[0053] (2) ECU17 sets the upper limit V of the first speed range calculated according to formulas (2) and (3). max (i) and lower limit V min (i) and the upper limit of the second speed range obtained from the speed constraint information v max (i) and lower bound v min (i) Based on the above, the upper limit W of the velocity range W(i) max (i) and lower limit W min (i) is determined. According to this configuration, acceleration constraint information and endpoint velocity v end Information regarding discrete point intervals (multiple discrete points S1~S N interval δ1~δ N-1 Using information about speed constraints, the upper limit W of the speed range W(1) to W(N) is determined. max (1) ~ W max (N) and lower limit W min (1) ~ W min (N) can be determined sequentially starting from the endpoint.

[0054] (3) ECU17 is the upper limit α of the first acceleration range calculated according to formula (6). max (i) and the upper limit a of the second acceleration range obtained from the acceleration constraint information. max (i) Based on this, the upper limit A of acceleration range A(i) max (i) is determined, and this upper limit A maxBased on (i), etc., multiple discrete points S1~S according to formula (8) N The travel speeds V(1) to V(N) as the vehicle passes through each of these points are calculated and determined. According to this configuration, the starting speed v start Information regarding discrete point intervals and the upper limit W of the velocity range W(1)~W(N) max (1) ~ W max Using (N) and acceleration constraint information, discrete points S1~S N The travel speeds V(1) to V(N) as the device passes through each of these points can be determined sequentially from the starting point.

[0055] (4) The speed determination method for determining the travel speeds V(1) to V(N) of forklift 1 comprises steps S1 (information acquisition step) for acquiring speed constraint information and acceleration constraint information, steps S2 to S6 (speed range determination steps), and steps S9 to S12 (speed determination steps). In steps S2 to S6, discrete points S1 to S N Upper limit W of the velocity range W(1)~W(N) in each of these max (1) ~ W max (N) and lower limit W min (1) ~ W min (N) is determined sequentially from the endpoint side, and in steps S9 to S12, the upper limit W of the speed range W(1) to W(N) is determined. max (1) ~ W max Based on (N), etc., discrete points S1~S N-1 Acceleration and discrete points S1~S at each of these points N The travel speeds V(1) to V(N) at each of these points are determined sequentially from the starting point. With this configuration, the effects described in (1) above can be obtained.

[0056] The present invention is not limited to the embodiments described above, and the above configuration can be modified. For example, it can be implemented with the following modifications, or a combination of the following modifications can be used.

[0057] The speed planning system does not necessarily have to be installed on the forklift 1. For example, the travel speed planning system may be installed on a control device 2 (see Figure 5) that is configured to communicate with the forklift 1.

[0058] Referring to Figure 5, a modified speed planning system will be described. Note that the same configuration as in the above embodiment will be omitted from the description. As shown in Figure 5, the speed planning system according to this modified example consists of a memory 21 and a CPU (Central Processing Unit) 22 provided in a management device 2 configured to communicate with the forklift 1.

[0059] Memory 21 functions as a storage unit that stores discrete point interval information, velocity constraint information, acceleration constraint information, and specified velocity information.

[0060] The CPU 22 functions as a speed range determination unit and a speed determination unit as described in the above embodiment. That is, the CPU 22 receives speed constraint information, acceleration constraint information, and endpoint speed v end Based on the information, the upper limit W of the speed range W(1)~W(N) max (1) ~ W max (N) and lower limit W min (1) ~ W min (N) is determined sequentially from the endpoint side. Furthermore, the CPU22 uses acceleration constraint information and the starting velocity v start Information regarding the upper limit W of the speed range W(1)~W(N) max (1) ~ W max Based on (N), discrete points S1~S N-1 Acceleration and discrete points S1~S at each of these points N The travel speeds V(1) to V(N) at each point are determined sequentially from the starting point.

[0061] The speed information regarding the travel speed V(1) to V(N) determined by the CPU 22 is transmitted from the management device 2 to the forklift 1 and stored in the forklift 1's memory 16. Then, the forklift 1's ECU 17 controls the drive unit 12 so that the vehicle body 1A travels at the travel speed V(1) to V(N) or acceleration determined by the CPU 22, based on the speed information stored in the memory 16.

[0062] The velocity determination unit determines multiple discrete points S1~S N Without determining the travel speed V(1)~V(N) at each of the multiple discrete points S1~S N-1 Only the acceleration at each of the multiple discrete points may be determined. That is, the velocity determination unit only needs to determine the running speed or acceleration at each of the multiple discrete points, and the velocity information only needs to include information about the determined running speed or acceleration. In addition, in a configuration where the velocity determination unit determines the running speed and acceleration at each of the multiple discrete points, the velocity information may include information about both the determined running speed and acceleration.

[0063] Starting velocity v start and final speed v end This value may be anything other than 0. Furthermore, while an automated vehicle is traveling along a predetermined path from a starting point to an ending point, the speed determination unit may determine the travel speed or acceleration required to travel from the new starting point to the new ending point, using the ending point as a new starting point.

[0064] • Forklift 1 may be an AGF other than a laser guidance system. That is, the autonomous vehicle may be an autonomous vehicle using a gyro guidance system equipped with a gyro sensor, or an autonomous vehicle using a magnetic guidance system equipped with a magnetic sensor.

[0065] • Forklift 1 is not limited to a reach forklift, but may also be a counterbalanced forklift. Furthermore, the present invention may be applied to autonomous vehicles other than forklift 1 (e.g., automated guided vehicles). [Explanation of Symbols]

[0066] 1. Forklift (autonomous vehicle) 2 Management device 16. Memory (storage unit) 17. ECU (Speed ​​Range Determination Unit, Speed ​​Determination Unit, Driving Control Unit) 21. Memory (storage unit) 22 CPU (speed range determination section, speed determination section)

Claims

1. In an automated vehicle that travels along a predetermined route from a starting point to an ending point located along that route, A storage unit that stores speed constraint information relating to speed constraints when passing through a plurality of discrete points located on the path from the starting point to the ending point, and acceleration constraint information relating to acceleration constraints at the plurality of discrete points, A speed range determination unit that determines the upper limit of the speed range at each of the plurality of discrete points in order from the endpoint side, based on the speed constraint information, the acceleration constraint information, and information regarding the endpoint speed, which is the speed at the endpoint. A speed determination unit that determines the running speed or acceleration at each of the plurality of discrete points in order from the starting point side, based on the acceleration constraint information, information on the starting point speed which is the running speed at the starting point, and the upper limit of the speed range at each of the plurality of discrete points determined by the speed range determination unit, The system includes a driving control unit that controls the vehicle's movement based on speed information relating to the driving speed or acceleration determined by the speed determination unit. An autonomous vehicle characterized by the following features.

2. The speed range determination unit, Based on the acceleration constraint information, the information regarding the endpoint velocity, and the information regarding the intervals between the plurality of discrete points, the upper limit of the first velocity range is calculated. Based on the upper limit of the first speed range and the upper limit of the second speed range obtained from the speed constraint information, the smaller of the upper limit of the first speed range and the upper limit of the second speed range is determined as the upper limit of the speed range. The autonomous vehicle according to feature 1.

3. The speed determination unit, Based on the information regarding the starting point velocity, the information regarding the intervals between the plurality of discrete points, and the upper limit of the velocity range at each of the plurality of discrete points determined by the velocity range determination unit, the upper limit of the first acceleration range is calculated. Based on the upper limit of the first acceleration range and the upper limit of the second acceleration range obtained from the acceleration constraint information, the smaller of the upper limit of the first acceleration range and the upper limit of the second acceleration range is determined as the upper limit of the acceleration range. Based on the upper limit of the acceleration range, the information regarding the starting point velocity, and the information regarding the intervals between the plurality of discrete points, the travel speed when passing through each of the plurality of discrete points is calculated and determined. The autonomous vehicle according to feature 2.

4. In a speed determination system that determines the driving speed or acceleration of an automated vehicle traveling along a predetermined route from a starting point to an ending point located along that route, A storage unit that stores speed constraint information relating to speed constraints when passing through a plurality of discrete points located on the path from the starting point to the ending point, and acceleration constraint information relating to acceleration constraints at the plurality of discrete points, A speed range determination unit that determines the upper limit of the speed range at each of the plurality of discrete points in order from the endpoint side, based on the speed constraint information, the acceleration constraint information, and information regarding the endpoint speed, which is the speed at the endpoint. The system includes a speed determination unit that determines the running speed or acceleration at each of the plurality of discrete points in order from the starting point side, based on the acceleration constraint information, information on the starting point speed which is the running speed at the starting point, and the upper limit of the speed range at each of the plurality of discrete points determined by the speed range determination unit. A speed determination system characterized by the following features.

5. A method for determining the speed or acceleration of an automated vehicle traveling along a predetermined route from a starting point to an ending point located along that route, An information acquisition step of acquiring speed constraint information relating to speed constraints when passing through a plurality of discrete points located on the path from the starting point to the ending point, and acceleration constraint information relating to acceleration constraints at the plurality of discrete points, A speed range determination step in which, based on the speed constraint information, the acceleration constraint information, and information regarding the endpoint speed which is the speed at the endpoint, the upper limit of the speed range at each of the plurality of discrete points is determined sequentially from the endpoint side, The system includes a speed determination step which determines the running speed or acceleration at each of the plurality of discrete points in order from the starting point side, based on the acceleration constraint information, information on the starting point speed which is the running speed at the starting point, and the upper limit of the speed range at each of the plurality of discrete points determined in the speed range determination step. A method for determining speed characterized by the following features.

Images