Mobile object control system, control method thereof, program, and recording medium

Abstract

To provide a mobile-body control system capable of generating a travel track for a mobile body that has a drive wheel and a driven wheel, while appropriately considering an angle of the driven wheel.SOLUTION: A mobile-body control system for controlling an action of a mobile body that includes a drive wheel and a driven wheel includes: generation means for generating a track for the mobile body on the basis of a track and a target position, which can be generated from a speed and an angular velocity of the mobile body that satisfies a given limiting condition; and control means for controlling travel of the mobile body along the generated track. Further, the given limiting condition includes: a limitation determined from a speed at which the mobile body can travel; a limitation determined from acceleration at which the mobile body can accelerate; and a limitation in accordance with an angle of the driven wheel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mobile object control system, a control method therefor, a program, and a recording medium. [Background technology]

[0002] In recent years, there has been an increasing demand for ultra-compact mobile vehicles (micromobility) to support people's mobility within small areas. Micromobility vehicles include vehicles with a passenger capacity of around one person, and vehicles that travel alongside people, carrying luggage instead of passengers. Micromobility can travel in both areas where cars are used and areas where pedestrians are used, so it requires autonomous driving technology for traveling on roadways as well as autonomous mobility technology for free spaces such as sidewalks. Micromobility vehicles are sometimes configured with a relatively simple drive system, such as a two-wheel differential, to achieve their small size and maneuverability.

[0003] Patent document 1 proposes a technology for an autonomous mobile cart equipped with two drive wheels and casters, in which the rotation angle of the casters relative to the direction of travel is calculated based on the orientation of the casters and a speed command value relative to the direction of travel of the cart, and the speed command value is limited when a predetermined rotation angle is reached. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-136319 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a micromobility vehicle has a drive wheel and a driven wheel that form a two-wheel differential, the angle of the driven wheel can affect the motion of the micromobility, reducing its ability to follow a target trajectory and ride comfort. Therefore, how to take the angle of the driven wheel into account in a control algorithm for driving the micromobility vehicle to a destination position becomes an issue. In this regard, Patent Document 1 only considers limiting the speed command value when the turning angle exceeds a predetermined value.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to realize a technology that can generate a driving trajectory of a mobile body having driving wheels and passive wheels while appropriately taking into account the angle of the driven wheels. [Means for solving the problem]

[0007] According to the present invention, A mobile object control system for controlling the operation of a mobile object having driving wheels and driven wheels, a generation means for generating a trajectory along which the moving body will travel, based on a target position and a trajectory that can be generated from the velocity and angular velocity of the moving body that satisfy predetermined constraints; a control means for controlling the travel of the moving body in accordance with the generated trajectory, The predetermined constraint is determined based on the speed at which the moving object can travel. The velocity and angular velocity of the moving body It is determined from the constraints and the acceleration that the moving body can accelerate. The velocity and angular velocity of the moving body constraints and the angle of the driven wheel The velocity and angular velocity of the moving body A vehicle control system is provided, comprising:

[0008] Further, according to the present invention, A control method for a mobile object control system that controls the operation of a mobile object having driving wheels and driven wheels, comprising: generating a trajectory along which the moving body will travel based on a target position and a trajectory that can be generated from the velocity and angular velocity of the moving body that satisfy predetermined constraints; and controlling the travel of the moving object according to the generated trajectory; A control method for a mobile body control system is provided, characterized in that the predetermined constraint conditions include a constraint determined from the speed at which the mobile body can travel, a constraint determined from the acceleration at which the mobile body can accelerate, and a constraint according to the angle of the driven wheels.

[0009] Further, according to the present invention, A program for causing a computer to function as each means of a mobile object control system for controlling the operation of a mobile object having driving wheels and driven wheels, the mobile object control system comprising: a generation means for generating a trajectory along which the moving body will travel, based on a target position and a trajectory that can be generated from the velocity and angular velocity of the moving body that satisfy predetermined constraints; a control means for controlling the travel of the moving body in accordance with the generated trajectory, The program is characterized in that the predetermined constraint conditions include a constraint determined from the speed at which the mobile body can travel, a constraint determined from the acceleration at which the mobile body can accelerate, and a constraint according to the angle of the driven wheels. [Effects of the Invention]

[0010] According to the present invention, it is possible to generate a travel trajectory for a mobile body having drive wheels and passive wheels while appropriately considering the angle of the driven wheels. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a moving body according to an embodiment of the present invention; [Figure 2] FIG. 1 is a block diagram showing an example of the configuration of a control system of a moving body according to an embodiment; [Figure 3] FIG. 1 is a block diagram showing an example of a functional configuration related to a control unit of a moving body according to an embodiment; [Figure 4] FIG. 1 is a diagram schematically illustrating an example of a grid map according to an embodiment. [Figure 5] FIG. 1 is a diagram schematically illustrating a range (window) that satisfies constraints on the velocity and angular velocity of a moving body according to an embodiment. [Figure 6] FIG. 1 is a diagram illustrating modeling of a moving object according to an embodiment. [Figure 7] FIG. 10 is a diagram showing constraints on driven wheels of a moving body according to an embodiment; [Figure 8] 1 is a flowchart showing a series of operations in a trajectory generation process according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.

[0013] In the following embodiment, an ultra-compact electric vehicle with a passenger capacity of about one person will be described as an example of a mobile body that is micromobility. However, micromobility may also include a vehicle that travels with a person while carrying luggage instead of a person on board. Furthermore, this embodiment is not limited to this example, and can also be applied to mobile bodies other than electric vehicles as long as the mobile body has a driven wheel. Furthermore, the following description will be given using an example in which there is one driven wheel, but the number of driven wheels is not limited to one and may be two or more.

[0014] For mobile vehicles such as the micromobility mentioned above, it would be useful to realize autonomous driving that takes into account the presence of people, the frequent changes in target location, and the lack of high-precision maps. Unlike unmanned delivery robots, when people ride in a mobile vehicle, selecting an unnatural driving trajectory or one that does not take into account the ride comfort could cause discomfort to the passengers. Furthermore, when accepting instructions for a target location from passengers, it is necessary to respond to changes in the target location. Furthermore, since the vehicle does not necessarily travel along a specific, fixed route and can travel in both areas traveled by automobiles and areas traveled by pedestrians, it is necessary to be able to navigate appropriately in areas where high-precision maps are not available.

[0015] The mobile body 100 according to this embodiment autonomously travels toward a target position that may be changed without using a high-precision map. To autonomously travel without using a high-precision map, the area in which the mobile body 100 can travel is identified using information recognized from the output of a detection unit, which will be described later. As will be described later, the mobile body 100 generates a grid map that indicates areas in which the mobile body 100 can travel and areas in which the mobile body 100 cannot travel, and uses this grid map to generate a travel trajectory for the mobile body 100. As will be described later in detail, the mobile body 100 generates a trajectory for the mobile body 100 by taking into account the angle of the driven wheels in a dynamic window approach (DWA).

[0016] <Configuration of moving body> The configuration of the moving body 100 will be described with reference to Fig. 1. Fig. 1(A) shows a side view of the moving body 100 according to this embodiment, and Fig. 1(B) shows the internal configuration of the moving body 100. In the figure, arrow X indicates the front-to-rear direction of the moving body 100, with F indicating the front and R indicating the rear. Arrows Y and Z indicate the width direction (left-to-right direction) and up-down direction of the moving body 100.

[0017] The mobile object 100 is an electric autonomous vehicle equipped with a propulsion unit 112 and using a battery 113 as its main power source. The battery 113 is, for example, a secondary battery such as a lithium-ion battery, and the mobile object 100 is self-propelled by the propulsion unit 112 using power supplied from the battery 113. The propulsion unit 112 is in the form of a tricycle equipped with a pair of left and right driving wheels 120 that are front wheels, and one driven wheel 121 that is a rear wheel. Note that the propulsion unit 112 may be in another form, such as a four-wheeled vehicle. The mobile object 100 is equipped with, for example, a seat 111 for one person.

[0018] The propulsion unit 112 includes a drive mechanism 122. The drive mechanism 122 is a mechanism that uses motors 122a and 122b as drive sources to rotate the corresponding drive wheels 120. The drive mechanism 122 can move the mobile body 100 forward or backward by rotating each of the drive wheels 120. The drive mechanism 122 can also change the direction of travel of the mobile body 100 by generating a rotation difference between the motors 122a and 122b. The propulsion unit 112 includes a driven wheel 121. The driven wheel can rotate around the Z direction as its rotation axis.

[0019] The moving body 100 is equipped with detection units 114 to 116 that detect targets around the moving body 100. The detection units 114 to 116 are a group of external sensors that monitor the periphery of the moving body 100. In the present embodiment, the detection units 114 to 116 are all imaging devices that capture images of the periphery of the moving body 100, and include, for example, an optical system such as a lens and an image sensor. However, instead of or in addition to the imaging devices, radar or lidar (Light Detection and Ranging) may be used.

[0020] The detection units 114 are arranged, for example, in pairs at the front of the moving body 100, spaced apart in the Y direction, and are mainly used to detect targets ahead of the moving body 100. The detection units 115 are arranged on the left and right sides of the moving body 100, respectively, and are mainly used to detect targets on the sides of the moving body 100. The detection unit 116 is arranged at the rear of the moving body 100, and is mainly used to detect targets behind the moving body 100.

[0021] 2 is a block diagram of a control system of the mobile object 100. The mobile object 100 includes a control unit (ECU) 130. The control unit 130 includes one or more processors such as a CPU, a memory device such as a semiconductor memory, an interface with an external device, etc. The memory device stores programs executed by the processor and data used by the processor for processing, etc. Multiple sets of processors, memory devices, and interfaces may be provided for different functions of the mobile object 100 and configured to be able to communicate with each other.

[0022] The control unit 130 acquires the outputs (e.g., image information) of the detection units 114 to 116, input information from the operation unit 131, and audio information input from the audio input device 133, and executes corresponding processing. The control unit 130 controls the motors 122a and 122b (controls the driving of the driving unit 112), controls the display of a display panel included in the operation unit 131, and outputs audio notifications and information to the occupants of the moving object 100. The control unit 130 may execute processing using a machine learning model for image recognition (e.g., a deep neural network) on the outputs from the detection units 114 to 116. The control unit 130 may also execute processing using a machine learning model for voice recognition (e.g., a deep neural network) on the outputs from the audio input device 133.

[0023] The voice input device 133 includes, for example, a microphone, and picks up the voice of the occupant of the mobile object 100. The control unit 130 can recognize the input voice and execute corresponding processing. The GNSS (Global Navigation Satellite system) sensor 34 receives GNSS signals and detects the current position of the mobile object 100.

[0024] The storage device 135 includes a recording medium for storing various data. The storage device 135 may also store programs executed by the processor, data used by the processor for processing, etc. The storage device 135 may also store various parameters of machine learning models for speech recognition and image recognition executed by the control unit 130 (for example, trained parameters and hyperparameters of a deep neural network, etc.).

[0025] The communication device 136 is a communication device that can communicate with an external device (for example, a communication terminal 140 owned by a user) via wireless communication such as Wi-Fi or fifth generation mobile communication.

[0026] Next, an example of the functional configuration of the control unit 130 will be described with reference to Fig. 3. The user instruction acquisition unit 301 acquires a user instruction input via the operation unit 131 or the voice input device 133. The user instruction includes a specification of a final target position where the moving object 100 should arrive. The final target position may be the position of a target designated by a spoken voice among targets recognized in the images output by the detection units 114 to 116. The user instruction may also include an instruction to change the traveling trajectory of the moving object 100, such as turning right or left, while the moving object 100 is traveling.

[0027] The image information processing unit 302 recognizes the position, shape, etc. of the road and obstacles based on the output (e.g., image information) of the detection units 114 to 116. The recognition of the position, shape, etc. of the road and obstacles ahead of the mobile object 100 is performed by, for example, calculating the depth from the mobile object 100 using stereo images obtained from the two detection units 114. To recognize the road and obstacles, a machine learning model for image recognition (e.g., a deep neural network) that has been trained in advance may be used on monocular images or stereo images.

[0028] The grid map generation unit 303 generates a grid map that indicates areas in the vicinity of the mobile object 100 that are drivable and areas that are not drivable for the mobile object 100, based on the positions, shapes, etc. of the travel path and obstacles recognized by the image information processing unit 302. Fig. 4 schematically shows an example of a grid map according to this embodiment. The example shown in Fig. 4 schematically shows how an image of the area ahead of the mobile object 402 is captured by the detection unit 403, and a grid map 400 is generated that indicates an impassable area 401 indicating the presence of an obstacle and other areas (drivable areas).

[0029] The grid map generation unit 303 shifts the grid map 400 as the moving object 100 moves so that the moving object is positioned at the center of the grid map. The grid map generation unit 303 assigns the non-drivable areas 401 to the corresponding grids of the grid map 400 according to the recognition results of the image information processing unit 302. The grid map generation unit 303 generates a grid map by adding the non-drivable areas 401 as the moving object 100 moves.

[0030] The path generation unit 304 executes a path generation process, which will be described later, to generate a path (traveling path) along which the mobile object 100 will travel. The path generation unit 304 uses, for example, a dynamic window approach (DWA) to generate the traveling path. The DWA can generate a path along which the mobile object 100 will travel, taking into account constraints such as kinematics and acceleration. The traveling path generated by the path generation unit 304 of this embodiment may be referred to as a local path in contrast to a global path, which will be described later. The global path is a path toward a target position that is longer than a path generated using DWA (i.e., a local path). The path generation unit 304 can generate a path based on the target position by referring to the global path.

[0031] When DWA is used, for example, the path generation unit 304 determines combinations of the velocities and angular velocities of the moving object that satisfy the constraint conditions described below, and generates a trajectory for each combination. Then, the path generation unit 304 substitutes the generated trajectories into a cost function and selects the trajectory with the lowest cost. Alternatively, the path generation unit 304 may select the trajectory closest to the target position from the generated trajectories.

[0032] FIG. 5 schematically shows ranges (windows) that satisfy constraints on the velocity and angular velocity of a moving object, used by the path generation unit 304 according to this embodiment. The horizontal axis ω of FIG. 5 represents the angular velocity of the moving object, and the vertical axis v of FIG. 5 represents the velocity of the moving object. A moving object 501 is schematically shown at the origin. The obstacle window 502 indicates the range of velocity and angular velocity within which the moving object 100 will not collide with an obstacle. The velocity constraint window 503 indicates the range of velocity of the moving object 100, determined from the speed at which the moving object 100 can travel. The acceleration constraint window 504 indicates the range of velocity and angular velocity of the moving object, determined from the acceleration at which the moving object 100 can accelerate (critical acceleration). In DWA, the combination of velocity and angular velocity included in all of the obstacle window 502, velocity constraint window 503, and acceleration constraint window 504 is the velocity and angular velocity that satisfies all three constraints.

[0033] The path generating unit 304 uses the above constraints as well as constraints on the speed and angular velocity according to the angle of the driven wheels. FIG. 6 shows a diagram modeling a moving object including two driving wheels 120 and one driven wheel 121. In FIG. 6, the speed in the traveling direction is represented by v, the angular velocity by ω, the length from the axle of the driving wheels to the center position of the driven wheel by L, and the radius of curvature by R. The angle between the angle of the driven wheel and the traveling direction of the moving object (also referred to as the angle δ of the driven wheel) can be estimated according to the following equation (1). That is, the path generating unit 304 can estimate the angle of the driven wheel based on the speed of the moving object, the angular velocity of the moving object, and the distance of the driven wheel from the axle of the driving wheels.

[0034]

number

[0035] Furthermore, FIG. 7 shows constraints on the velocity v and angular velocity ω set for the moving body in the moving body model shown in FIG. 6. FIG. 7(a) shows constraints on the angle δ of the driven wheels and the velocity v of the moving body. FIG. 7(b) shows constraints on the angle δ of the driven wheels and the angular velocity ω of the moving body. The constraint taking into account the angle δ of the driven wheels imposes a constraint to reduce the deviation between the direction of the driven wheels and the traveling direction of the moving body. By complying with the constraints shown in FIGS. 7(a) and 7(b), the path generation unit 304 travels at a low speed until the direction of the driven wheels approaches the traveling direction of the moving body 100.

[0036] 7(a), when the absolute value of the angle δ between the angle of the driven wheel and the traveling direction of the moving object is greater than a predetermined value (e.g., π / 4), the velocity of the moving object is restricted to a smaller value as the absolute value of the angle δ approaches vertical. That is, the path generating unit 304 restricts the value of v more as the angle δ approaches π / 2 and -π / 2.

[0037] In the constraint condition 702 in FIG. 7(b), when the angle δ between the angle of the driven wheel and the traveling direction of the moving body is greater than a predetermined value (for example, π / 4), the positive angular velocity of the moving body is limited to a smaller value as the angle approaches 90 degrees. On the other hand, the negative angular velocity of the moving body is not limited. Conversely, the negative angular velocity of the moving body is limited to a smaller value as the angle approaches -90 degrees, and the positive angular velocity is not limited. This means that the path generation unit 304 does not limit the magnitude of the angular velocity as long as the angular velocity is in a direction that reduces the deviation between the angle δ of the driven wheel and the traveling direction.

[0038] The path generation unit 304 determines a combination of velocities and angular velocities that satisfies all of the constraints on the velocity and angular velocity of the moving object (constraints described with reference to FIGS. 5 and 7), and generates a trajectory for each combination. Next, the path generation unit 304 substitutes the generated trajectories into a cost function. The cost function is expressed as in equation (2). Here, C error is the deviation cost from a given global path, C velocity is the cost of tracking the target speed, C obstacle represents the cost of approaching and colliding with an obstacle. The cost of deviation from the global path is configured to decrease as the difference (deviation) between the generated trajectory and the global path decreases. The cost of approaching and colliding with an obstacle is configured, for example, by projecting the trajectory onto a grid map, so that the closer the distance to the non-travelable area (obstacle), the higher the cost. The path generation unit 304 selects the speed v and angular velocity ω that minimize the cost function according to equation (3). In this way, the path generation unit 304 can generate the traveling trajectory of the mobile body 100 while appropriately considering the angle of the driven wheels when generating the traveling trajectory using DWA.

[0039]

number

[0040]

number

[0041] In the above example, a traveling trajectory is generated according to equation (2) by referring to a global trajectory created in advance for the target position. The global trajectory is a trajectory for heading to the target position that is longer than the trajectory (i.e., the local trajectory) generated according to equation (2). By referring to the global trajectory, the trajectory generation unit 304 can realize the generation of a trajectory around the vehicle that avoids obstacles while taking into account vehicle motion (by DWA) while following a roughly determined trajectory to the target position. However, it is not essential to provide a global trajectory, and if the target position can be considered separately, it is possible to use C in equation (2). error It is not necessary to use

[0042] The path generation unit 304 may consider a more optimal driving trajectory for the generated driving trajectory, for example, by using a cost grid. The cost grid may be composed of the same number of grids as the grid map. Each grid in the cost grid is assigned a cost value. Multiple cost grids can be used, and multiple cost grids can be taken into account by, for example, summing the values ​​of corresponding grids. In a cost grid that handles differences from a global path, for example, when a global path is projected onto a grid surface, a lower cost value is assigned to a grid closer to the global path. In addition, in a cost grid that handles the cost of approaching or colliding with an obstacle, a higher cost is assigned to each grid in the cost grid closer to the obstacle. The path generation unit 304 stores the set cost grid in a memory device, and when a candidate trajectory is generated, it projects the driving trajectory onto the cost grid and sums the cost values ​​of the grids that overlap with the driving trajectory. For example, the path generation unit 304 determines an initial trajectory that satisfies the above-mentioned constraints and calculates the cost of the initial trajectory by determining the overlap between the initial trajectory and the cost grid. Next, the path generation unit 304 calculates an updated trajectory that satisfies the constraints and reduces the cost (for example, by using the gradient of the cost grid). The path generation unit 304 projects the updated trajectory onto the cost grid and determines whether it overlaps with the cost grid. By repeating this process, an optimal trajectory can be obtained by a relatively simple calculation of projecting the trajectory onto the cost grid.

[0043] <Series of operations in trajectory generation processing for moving body 100> Next, a series of operations in the trajectory generation process of the moving body 100 will be described with reference to FIG. 8. This process is realized by the control unit 130 loading a program stored in the storage device 135 into the memory device of the control unit 130 and executing it. At the start of this process, it is assumed that a grid map and a global route have been generated by another process and stored in the memory device. The grid map and the global route in the memory device are updated at a predetermined timing by another process executed in parallel. It is also assumed that a final destination position has been set according to a user instruction or the like.

[0044] In S901, the path generation unit 304 of the control unit 130 obtains a global path stored in a memory device. In S902, the path generation unit 304 determines a combination of speed and angular velocity that satisfies the constraints. The constraints include the obstacle window 502, the speed constraint window 503, the acceleration constraint window 504, and the constraints 701 and 702 related to the driven wheels, which have been described with reference to FIGS. 5 and 7.

[0045] In S903, the path generation unit 304 generates a trajectory for each combination of speed and angular velocity. In S904, the path generation unit 304 substitutes the generated trajectory into a cost function. Then, the path generation unit 304 selects the trajectory with the lowest cost of the cost function. The path generation unit 304 calculates the cost of the trajectory using, for example, the above-mentioned equation (2) as the cost function. Furthermore, the path generation unit 304 selects the trajectory with the lowest cost (the speed and angular velocity of the mobile object 100) according to equation (3). The path generation unit 304 may select the trajectory with the lowest cost by optimizing the curvature of, for example, three points on a traveling trajectory that is a combination of multiple arc trajectories. Alternatively, the path generation unit 304 may select the trajectory with the lowest cost by using the above-mentioned cost grid.

[0046] In S905, the traveling control unit 305 controls the traveling of the moving body 100 according to the selected trajectory. In S906, the control unit 130 determines whether the moving body 100 has arrived at the final destination position. The control unit 130 determines whether the moving body 100 has arrived at the final destination position. If the control unit 130 determines that the moving body 100 has arrived at the final destination position, this series of processes ends; if not, the process returns to S901.

[0047] As described above, in the above-described embodiment, a trajectory for a mobile body having drive wheels and driven wheels is generated based on a target position and a trajectory that can be generated from the speed and angular velocity of the mobile body, which satisfies predetermined constraints. In this case, the predetermined constraints include constraints on the speed and angular velocity of the mobile body determined from the speed at which the mobile body can travel, constraints on the speed and angular velocity of the mobile body determined from the acceleration at which the mobile body can accelerate, and constraints on the speed and angular velocity of the mobile body according to the angle of the driven wheels. In this way, a trajectory for a mobile body having drive wheels and driven wheels can be generated while appropriately considering the angle of the driven wheels.

[0048] The configuration of the control unit 130 described above may function in various forms as a mobile object control system. For example, a mobile object control system may be configured in a form in which at least a part of the control unit 130 described above is configured on a device external to the mobile object 100, such as an external server. Alternatively, the mobile object control system may be the mobile object 100. Furthermore, the computer program that operates the mobile object 100 described above may be a computer program that causes one or more computers to function as each means of the mobile object control system. Furthermore, the mobile object control system may be the control unit 130.

[0049] <Summary of the embodiment> 1. The mobile object control system for controlling the operation of the mobile object (e.g., 100) of the above embodiment is A mobile object control system for controlling the operation of a mobile object having a driving wheel (e.g., 120) and a driven wheel (e.g., 121), A generating means (e.g., 304) for generating a trajectory along which the moving body will travel, based on a trajectory that can be generated from the velocity and angular velocity of the moving body that satisfy predetermined constraints and a target position; and a control means (e.g., 305) for controlling the travel of the moving body according to the generated trajectory; The predetermined constraint conditions include a constraint determined from the speed at which the mobile object can travel, a constraint determined from the acceleration at which the mobile object can accelerate, and a constraint according to the angle of the driven wheels.

[0050] According to this embodiment, it is possible to generate a travel trajectory for a mobile body having driving wheels and passive wheels while appropriately considering the angle of the driven wheels.

[0051] 2. In the mobile object control system of the above embodiment, The predetermined constraint is that when the absolute value of the angle between the angle of the driven wheel and the traveling direction of the moving body is greater than a predetermined value, the magnitude of the speed of the moving body is limited to a smaller value as the absolute value of the angle approaches vertical.

[0052] According to this embodiment, it is possible to generate a travel trajectory of a moving body in which an appropriate speed is set according to the angle of the driven wheels.

[0053] 3. In the mobile object control system of the above embodiment, The specified constraint condition is that when the angle between the angle of the driven wheel and the direction of travel of the moving body is greater than a specified value, the positive angular velocity of the moving body is limited to a smaller value as the angle approaches vertical, but the negative angular velocity of the moving body is not limited.

[0054] According to this embodiment, it is possible to generate a travel trajectory of a moving body in which an appropriate angular velocity of the moving body is set according to the angle of the driven wheel.

[0055] 4. In the mobile object control system of the above embodiment, The predetermined constraint conditions further include a constraint for preventing the moving body from colliding with an obstacle.

[0056] According to this embodiment, it is possible to generate a travel trajectory of a moving object that avoids collision with an obstacle.

[0057] 5. In the mobile object control system of the above embodiment, The generating means generates, as a trajectory for the moving body, a trajectory that is closest to the target position from among trajectories that can be generated from the speed and angular velocity of the moving body that satisfy predetermined constraints.

[0058] According to this embodiment, the shortest route to the target position can be generated as the travel trajectory while taking into consideration the angle of the driven wheels.

[0059] 6. In the mobile object control system of the above embodiment, The vehicle further includes an estimation means for estimating the angle of the driven wheel based on the speed of the moving body, the angular velocity of the moving body, and the distance of the driven wheel from the axle of the driving wheel.

[0060] According to this embodiment, the angle of the driven wheel can be obtained without using an additional sensor.

[0061] 7. In the mobile object control system of the above embodiment, The target position is a point on a global path that is acquired in advance and has a longer distance than the trajectory generated by the generating means.

[0062] According to this embodiment, it is possible to generate a path that does not deviate from the global path.

[0063] 8. In the mobile object control system of the above embodiment, The constraint conditions include constraints on the speed and angular velocity of the moving body determined from the speed at which the moving body can travel, constraints on the speed and angular velocity of the moving body determined from the acceleration at which the moving body can accelerate, and constraints on the speed and angular velocity of the moving body according to the angle of the driven wheels.

[0064] According to this embodiment, it is possible to give the moving body a speed and angular velocity appropriate for its travel.

[0065] 9. In the mobile object control system of the above embodiment, The constraints for preventing the moving body from colliding with an obstacle include constraints on the velocity and angular velocity of the moving body for preventing the moving body from colliding with an obstacle.

[0066] According to this embodiment, it is possible to give an appropriate velocity and angular velocity of the moving body taking into account obstacles.

[0067] 10. In the mobile object control system of the above embodiment, The generating means generates, as a trajectory for the moving body to travel, a trajectory that minimizes the cost of a predetermined cost function from among trajectories that can be generated from the speed and angular velocity of the moving body that satisfy predetermined constraints.

[0068] According to this embodiment, it is possible to generate an optimized trajectory that takes into account various constraints from the velocities and angular velocities of the moving body that satisfy the constraint conditions.

[0069] 11. In the mobile object control system of the above embodiment, The predetermined cost function reduces the cost as the difference between the generated trajectory and the global path decreases.

[0070] According to this embodiment, a travel trajectory along a given global route can be generated.

[0071] 12. In the mobile object control system of the above embodiment, The predetermined cost function has a smaller cost as the difference between the trajectory to be generated and the trajectory generated immediately before is smaller.

[0072] According to this embodiment, it is possible to suppress abrupt changes in the orbit.

[0073] 13. In the mobile object control system of the above embodiment, The predetermined cost function has a higher cost the closer the generated trajectory is to an obstacle.

[0074] According to this embodiment, a travel trajectory can be generated that reduces the risk of collision with an obstacle.

[0075] 14. In the mobile object control system of the above embodiment, The vehicle is a micromobility vehicle that can be ridden by people.

[0076] According to this embodiment, in micromobility, it is possible to generate a travel trajectory for a mobile body having driving wheels and passive wheels while appropriately considering the angle of the driven wheels.

[0077] 15. In the mobile object control system of the above embodiment, The mobile object control system is a mobile object having a generating means and a controlling means.

[0078] According to this embodiment, the vehicle control system is provided as a vehicle.

[0079] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0080] 100... Mobile body, 120... Driving wheel, 121... Driven wheel, 130... Control unit, 303... Grid map generating unit, 304... Route generating unit, 305... Travel control unit

Claims

1. A mobile object control system for controlling the operation of a mobile object having driving wheels and driven wheels, a generation means for generating a trajectory along which the moving body will travel, based on a target position and a trajectory that can be generated from the velocity and angular velocity of the moving body that satisfy predetermined constraints; a control means for controlling the travel of the moving body in accordance with the generated trajectory, A mobile body control system characterized in that the predetermined constraint conditions include constraints on the speed and angular velocity of the mobile body determined from the speed at which the mobile body can travel, constraints on the speed and angular velocity of the mobile body determined from the acceleration at which the mobile body can accelerate, and constraints on the speed and angular velocity of the mobile body according to the angle of the driven wheels.

2. 2. The mobile body control system according to claim 1, wherein the predetermined constraint condition is such that, when the absolute value of the angle of the driven wheel is greater than a predetermined value, the magnitude of the velocity of the mobile body is limited to a smaller value as the absolute value of the angle of the driven wheel approaches vertical.

3. 2. The mobile body control system according to claim 1, wherein the predetermined constraint condition is such that, when the angle of the driven wheel is greater than a predetermined value, the positive angular velocity of the mobile body is limited to a smaller value as the angle of the driven wheel approaches vertical, but the negative angular velocity of the mobile body is not limited.

4. 2. The mobile object control system according to claim 1, wherein the predetermined constraint conditions further include constraints on the speed and angular velocity of the mobile object so as to prevent the mobile object from colliding with an obstacle.

5. 2. The mobile body control system according to claim 1, wherein the generation means generates, as a trajectory for the mobile body to travel, a trajectory that is closest to the target position from among trajectories that can be generated from the velocity and angular velocity of the mobile body that satisfy the predetermined constraint conditions.

6. 2. The mobile body control system according to claim 1, further comprising an estimation means for estimating the angle of the driven wheel based on the speed of the mobile body, the angular velocity of the mobile body, and the distance of the driven wheel from the axle of the drive wheel.

7. 2. The mobile object control system according to claim 1, wherein the target position is a point on a global path that is acquired in advance and that has a longer distance than the trajectory generated by the generating means.

8. 8. The mobile body control system according to claim 7, wherein the generation means generates, as a trajectory for the mobile body to travel, a trajectory that minimizes the cost of a predetermined cost function from among trajectories that can be generated from the velocity and angular velocity of the mobile body that satisfy the predetermined constraint conditions.

9. 9. The mobile object control system according to claim 8, wherein the predetermined cost function is such that the cost decreases as the difference between the generated trajectory and the global path decreases.

10. 9. The mobile object control system according to claim 8, wherein the predetermined cost function is such that the cost decreases as the difference between the trajectory to be generated and the trajectory generated immediately before decreases.

11. 9. The mobile object control system according to claim 8, wherein the predetermined cost function is such that the closer the distance between the generated trajectory and an obstacle, the higher the cost.

12. 2. The mobile object control system according to claim 1, wherein the mobile object is a micromobility vehicle that can be ridden by a person.

13. 2. The mobile body control system according to claim 1, wherein the mobile body control system is a mobile body having the generating means and the control means.

14. A control method for a mobile object control system that controls the operation of a mobile object having driving wheels and driven wheels, comprising: generating a trajectory along which the moving body will travel based on a target position and a trajectory that can be generated from the velocity and angular velocity of the moving body that satisfy predetermined constraints; and controlling the travel of the moving object according to the generated trajectory; a control method for a mobile body control system, wherein the predetermined constraint conditions include constraints on the speed and angular velocity of the mobile body determined from the speed at which the mobile body can travel, constraints on the speed and angular velocity of the mobile body determined from the acceleration at which the mobile body can accelerate, and constraints on the speed and angular velocity of the mobile body according to the angle of the driven wheels.

15. A program for causing a computer to function as each of the means of the mobile object control system according to any one of claims 1 to 13.

16. A recording medium storing a program for causing a computer to function as each of the means of the mobile object control system according to any one of claims 1 to 13.

Images