A method, device, and unmanned vehicle control system with speed-limited operation

Abstract

The present application provides a control method, device and unmanned vehicle with limited speed. The method includes: obtaining the current motion information of the unmanned vehicle with limited speed, including the current position and current orientation angle of the unmanned vehicle; setting the switching angle constraint of the unmanned vehicle under the corresponding time optimal motion trajectory configuration according to the motion characteristic information of the unmanned vehicle and the given motion duration; using the pre-constructed time optimal control law under different time optimal motion trajectory configurations and the constraint condition, calculating the target position that the unmanned vehicle can reach from the current position under the current orientation angle under each configuration; taking the set of all target positions as the isochrone of the unmanned vehicle under the time optimal motion condition; and controlling the unmanned vehicle to perform corresponding motion according to the isochrone. The method can obtain the isochrone of the time optimal motion in real time under the condition of limited speed of the unmanned vehicle, thereby providing optimal strategy support for motion control, etc.

Description

Technical Field

[0001] The present application relates to the technical field of unmanned vehicles, and in particular to a control method and device for an unmanned vehicle with limited rotation speed, and an unmanned vehicle. Background Art

[0002] Unmanned vehicles are one of the important representative equipment of robot technology engineering. They have played an active role in logistics distribution, traffic inspection, terrain mapping and other tasks. They are an important means to assist in the liberation of manual operation and can provide feasible technical solutions for the new generation of unmanned driving. The direction-changing drive of unmanned vehicles is generally a motor with saturated electromechanical characteristics. Since the maximum speed of the motor is saturated and limited, the speed of the unmanned vehicle is also saturated and limited. This brings challenges to the research of many aspects such as motion planning, isochrone calculation, tracking control and so on.

[0003] Among them, the isochrone of the unmanned vehicle, that is, the set of all target positions with equal motion duration along the time-optimal motion trajectory starting from the current position of the unmanned vehicle, is a typical digital representation of spatial information, which can provide optimal strategy support for tasks such as intelligent transportation, logistics distribution planning, and dynamic navigation. For the problem of isochrone calculation of unmanned vehicles, the existing technologies are mostly based on the motion model with unlimited speed, or directly discretizing the grid motion space and other methods to solve, and generally cannot provide real-time solutions for isochrones under time-optimal motion conditions. For scenarios that require real-time accessibility analysis, such as real-time traffic inspections, real-time distribution plan planning, real-time terrain mapping, etc., it is very necessary to conduct in-depth research on the problem of isochrone calculation of unmanned vehicles with limited speed under time-optimal motion conditions. Summary of the invention

[0004] In view of this, embodiments of the present application provide a speed-limited unmanned vehicle control method, device, and unmanned vehicle.

[0005] In a first aspect, an embodiment of the present application provides a method for controlling an unmanned vehicle with limited speed, comprising:

[0006] Acquire current motion information of the unmanned vehicle with limited speed, the motion information including the current position and current heading angle of the unmanned vehicle;

[0007] According to the motion characteristic information of the unmanned vehicle and the given motion duration, setting the constraint condition of the switching angle of the unmanned vehicle under the optimal motion trajectory configuration at the corresponding time, wherein the motion characteristic information includes the maximum rotation angular velocity of the unmanned vehicle;

[0008] Using the pre-constructed time-optimal control law and the constraint conditions under different time-optimal motion trajectory configurations, respectively calculate the target position that the unmanned vehicle can reach from the current position under the current orientation state under each configuration;

[0009] The set of all target positions in all configurations is taken as the isochrone of the unmanned vehicle in the case of time-optimal motion;

[0010] The unmanned vehicle is controlled to perform corresponding movement according to the isochrone.

[0011] In some embodiments, the four configurations of the time-optimal motion trajectory of the unmanned vehicle are obtained by predetermination, including:

[0012] Constructing a motion model related to current motion information of the unmanned vehicle;

[0013] Taking the optimal time for the unmanned vehicle to reach the target position from the current position as the goal, selecting the time optimal performance index function that satisfies the maximum rotation angular velocity constraint;

[0014] According to the motion model of the unmanned vehicle and the time-optimal performance index function, a corresponding Hamiltonian equation is constructed, and with the goal of minimizing the Hamiltonian equation, a corresponding motion trajectory expression when the rotation angular velocity takes different extreme values ​​under the time-optimal condition is determined;

[0015] According to different motion trajectory expressions, the configuration composition of the time optimal motion trajectory of the unmanned vehicle with limited speed is determined.

[0016] In one embodiment, the configurations of the time-optimal motion trajectory of the unmanned vehicle include four types: line segment, arc to line segment, arc, and line segment to arc; various configurations and the motion state of the unmanned vehicle satisfy the following relationship:

[0017] When the target position point is located directly in front of the current direction of the unmanned vehicle, the time optimal motion trajectory is a line segment;

[0018] When the target position point is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, or when the target position point is directly behind the current orientation of the unmanned vehicle, the time optimal motion trajectory is an arc turning line segment;

[0019] When the target position point is located on the rotation circle of the unmanned vehicle, the time-optimal motion trajectory is an arc;

[0020] When the target position point is located inside the rotating circle of the unmanned vehicle, the time-optimal motion trajectory is a line segment turning into an arc.

[0021] In some embodiments, the motion feature information further includes the running speed of the unmanned vehicle; the configuration of the time optimal motion trajectory of the unmanned vehicle includes a line segment, an arc to a line segment, an arc, and a line segment to an arc; the construction process of the time optimal control law under each time optimal motion trajectory configuration includes:

[0022] Determine the rotation radius of the unmanned vehicle according to the running speed and the maximum rotation angular velocity, and determine the expression of the rotation center of the unmanned vehicle in combination with the relative relationship between the current posture of the unmanned vehicle and any target position;

[0023] Based on the current position of the unmanned vehicle, the rotation radius and the rotation center, determine an expression for a switching point when the unmanned vehicle reaches any target position from the current position in each configuration, wherein the switching point is defined as a critical point where the time-optimal motion trajectory switches from a line segment to an arc segment or from an arc segment to a line segment;

[0024] Based on the current orientation angle of the unmanned vehicle and the switching point, determine an expression for the switching angle when the unmanned vehicle reaches any target position from the current position in each configuration, wherein the switching angle is defined as the angle between the current orientation angle of the unmanned vehicle and a line connecting the initial point of the arc segment and the terminal point of the arc segment;

[0025] Based on the switching angle and the maximum rotational angular velocity, an optimal control law for the time for the unmanned vehicle to reach the terminal direction from the current position under any conditions in each configuration is constructed with the rotational angular velocity as a variable.

[0026] In some embodiments, the switching point is calculated as follows:

[0027] When the time-optimal motion trajectory is a line segment, the current position of the unmanned vehicle is used as the switching point at this time;

[0028] When the time optimal motion trajectory is an arc turning line segment, when the target position is directly behind the current orientation of the unmanned vehicle, the switching point at this time is calculated according to the first formula; when the target position is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, the switching point at this time is calculated according to the second formula;

[0029] When the time-optimal motion trajectory is an arc, the target position of the unmanned vehicle is used as the switching point at this time;

[0030] When the time-optimal motion trajectory is a line segment turning into an arc, the switching point at this time is calculated according to the third formula based on the current position of the unmanned vehicle and the length of the unmanned vehicle moving in a straight line;

[0031] The first formula, the second formula and the third formula are respectively:

[0032]

[0033]

[0034] x t，3 =x+Le;

[0035] In the formula, x t，1 、x t，2 and x t，3 The switching points calculated using the first formula, the second formula, and the third formula can be represented in sequence; x = [xy] T is the current position of the unmanned vehicle; x f =[x f y f ] T is any target position; d is the distance from the target position to the rotation center x c The distance, x c =[x c y c ] T ;d t is the distance from the target position to the switching point; e is the unit vector of the current orientation of the unmanned vehicle; e f is the unit vector pointing from the current position to the target position; r = v / ω max is the rotation radius of the unmanned vehicle, where ω max is the maximum rotation angular velocity, v is the running speed of the unmanned vehicle; L is the length of the unmanned vehicle moving in a straight line; sign(·) represents the sign function.

[0036] In some embodiments, the switching angle is calculated as follows:

[0037] When the time optimal motion trajectory is a line segment, the switching angle is zero;

[0038] When the time-optimal motion trajectory is an arc or an arc-to-line segment, the switching angle at this time is calculated according to the current position of the unmanned vehicle, the unit vector of the current orientation and the switching point;

[0039] When the time-optimal motion trajectory is a line segment turning into a circular arc, the switching angle at this time is calculated according to the target position of the unmanned vehicle, the unit vector of the current orientation and the switching point.

[0040] In some embodiments, the construction of the time optimal control law of the unmanned vehicle includes:

[0041] When the time-optimal motion trajectory is a line segment, the time-optimal control law is set to zero;

[0042] When the time-optimal motion trajectory is an arc-turned line segment, when the target position is directly behind the current orientation of the unmanned vehicle, the first piecewise function is selected as the time-optimal control law; when the target position is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, the second piecewise function is selected as the time-optimal control law;

[0043] When the time-optimal motion trajectory is an arc, when the target position is located on the right side of the current posture of the unmanned vehicle, the time-optimal control law is set to a negative maximum rotation angular velocity; when the target position is located on the left side of the current posture of the unmanned vehicle, it is set to a positive maximum rotation angular velocity;

[0044] When the time-optimal motion trajectory is a line segment turning into a circular arc, a third piecewise function is selected as the time-optimal control law;

[0045] The first piecewise function, the second piecewise function and the third piecewise function are respectively:

[0046]

[0047]

[0048]

[0049] In the formula, and denote the time optimal control law represented by the first piecewise function, the second piecewise function and the third piecewise function respectively; t∈[t0, t f ] is the time variable of the unmanned vehicle movement, t0 is the initial time point, t f is the time point when the target position is reached; β is the switching angle.

[0050] In a second aspect, an embodiment of the present application provides a speed-limited unmanned vehicle control device, comprising:

[0051] An information acquisition module, used to acquire current motion information of the unmanned vehicle with limited speed, wherein the motion information includes a current position and a current orientation angle of the unmanned vehicle;

[0052] A constraint setting module, used to set the constraint conditions of the switching angle of the unmanned vehicle under the optimal motion trajectory configuration at the corresponding time according to the motion characteristic information of the unmanned vehicle and a given motion duration, wherein the motion characteristic information includes the maximum rotation angular velocity of the unmanned vehicle;

[0053] A calculation module, for calculating the target position that the unmanned vehicle can reach from the current position under the current heading angle in each configuration by using the pre-constructed time-optimal control law and the constraint conditions under different time-optimal motion trajectory configurations, and taking the set of all target positions under all configurations as the isochrone of the unmanned vehicle under the time-optimal motion condition;

[0054] A control module is used to control the unmanned vehicle to move accordingly according to the isochrone.

[0055] In a third aspect, an embodiment of the present application provides an unmanned vehicle, comprising a processor and a memory, wherein the memory stores a computer program, and the processor is used to execute the computer program to implement the above-mentioned speed-limited unmanned vehicle control method.

[0056] In a fourth aspect, an embodiment of the present application provides a readable storage medium storing a computer program, which, when executed on a processor, implements the above-mentioned speed-limited unmanned vehicle control method.

[0057] The embodiments of the present application have the following beneficial effects:

[0058] The control method of the embodiment of the present application is mainly for unmanned vehicles with limited speed. By obtaining the current position and current orientation angle of the unmanned vehicle with limited speed, the current motion information such as the current position and current orientation angle of the unmanned vehicle is obtained; according to the motion characteristic information of the unmanned vehicle and the given motion duration, the switching angle constraint of the unmanned vehicle under the corresponding time optimal motion trajectory configuration is set, and combined with the pre-constructed time optimal control law under different time optimal motion trajectory configurations, the target position that the unmanned vehicle can reach from the current position under the current orientation angle is calculated respectively under each configuration; the set of all target positions under all configurations is used as the isochrone of the unmanned vehicle under the time optimal motion condition; the unmanned vehicle is controlled to perform corresponding motion according to the isochrone. This method can solve the problem of isochrone calculation under the time optimal motion condition for unmanned vehicles with limited speed according to the current posture and motion duration of the unmanned vehicle, and can provide new ideas for the time optimal motion mechanism of unmanned vehicles with limited speed, and can also provide optimal strategies for tasks in various occasions such as motion planning, vehicle scheduling and accessibility analysis of unmanned vehicles. In addition, the method of this embodiment can also be migrated to other types of robots that meet the description of the motion model, and the isochrone information of the robot under the speed limited condition is obtained in real time, so as to facilitate motion control thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 A flow chart showing the configuration determination of the time optimal motion trajectory of an unmanned vehicle with limited speed according to an embodiment of the present application;

[0061] Figure 2 A flow chart showing construction of a time optimal control law for an unmanned vehicle with limited speed according to an embodiment of the present application is shown;

[0062] Figure 3 (a)- Figure 3 (c) are schematic diagrams showing the switching points when the target position in the embodiment of the present application is outside the rotating circle of the unmanned vehicle;

[0063] Figure 4 (a)- Figure 4 (b) schematic diagrams showing the switching points when the target position in the embodiment of the present application is inside the rotating circle of the unmanned vehicle;

[0064] Figure 5 (a)- Figure 5 (d) are schematic diagrams showing several relationships between the change angle of the movement direction of the unmanned vehicle and the switching angle in the embodiments of the present application;

[0065] Figure 6 A schematic diagram of the supremum of the distance that can be translated when the target position in the embodiment of the present application is inside the rotating circle of the unmanned vehicle is shown;

[0066] Figure 7 A flow chart showing a method for controlling an unmanned vehicle with limited speed according to an embodiment of the present application is shown;

[0067] Figure 8 A schematic diagram of isochrones for calculating an unmanned vehicle when a given running time is 5 seconds in an embodiment of the present application is shown;

[0068] Fig. 9 The isochronal diagrams are shown showing the locations that the unmanned vehicle in the embodiment of the present application can reach after moving for 3s, 4s, 5s, 6s, and 7s respectively;

[0069] Fig.10 A schematic structural diagram of a speed-limited unmanned vehicle control device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0071] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0072] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0073] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0074] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0075] The present application proposes a control method for an unmanned vehicle, which is mainly for an unmanned vehicle with limited speed. It uses a pre-determined configuration and a pre-designed time optimal control law to calculate the motion isochrone information of the unmanned vehicle under time optimality, and then uses the isochrone information to perform corresponding motion control of the unmanned vehicle, thereby providing a new idea for the time optimal motion of the unmanned vehicle with limited speed. In order to facilitate the understanding of the control method for an unmanned vehicle with limited speed in this embodiment, the following first describes the pre-determination of the time optimal motion trajectory configuration mentioned in the method, and the design of the time optimal control law of the unmanned vehicle with limited speed by introducing the concepts of switching points and switching angles.

[0076] First, considering the saturation constraint of the unmanned vehicle's direction-changing drive motor speed, in this embodiment, it is necessary to first obtain the motion characteristic information of the unmanned vehicle with limited speed, for example, including but not limited to the running speed, maximum rotation angular velocity, etc. of the unmanned vehicle. Among them, the time optimal motion of the unmanned vehicle in a uniform speed state is mainly considered here.

[0077] Next, in order to obtain the isochronal motion information under the time-optimal motion conditions of the unmanned vehicle, this embodiment will first determine the time-optimal motion trajectory configuration of the unmanned vehicle, wherein the configuration can be understood as the shape of the motion trajectory of the unmanned vehicle. In this embodiment, the configuration of the time-optimal motion trajectory of the unmanned vehicle includes four types, namely, line segment, arc to line segment, arc, and line segment to arc.

[0078] In one embodiment, Figure 1 As shown, the process of determining the time-optimal motion trajectory configuration of the unmanned vehicle may include steps S110 to S140:

[0079] S110, constructing a motion model related to the current motion information of the unmanned vehicle.

[0080] The current motion information of the unmanned vehicle may include, but is not limited to, the location of the unmanned vehicle and the motion direction angle, which may be obtained through a posture sensor installed on the unmanned vehicle. For example, the following motion model may be used:

[0081]

[0082] Where x = [xy] T is the current position of the unmanned vehicle, v is the running speed of the unmanned vehicle, θ is the current orientation angle of the unmanned vehicle, and ω is the rotation angular velocity, which is saturated and limited, that is, |ω|≤ω max .

[0083] S120, taking the optimal time for the unmanned vehicle to reach the target position from the current position as the goal, selecting the time optimal performance indicator function that satisfies the maximum rotation angular velocity constraint.

[0084] Among them, the time optimal performance index function is used to solve the motion control amount in the shortest time when the unmanned vehicle reaches the target position from the current position. It can be constructed using different types of optimization functions. There is no limitation here, as long as an optimization function related to the time variable and the motion control amount of the unmanned vehicle can be constructed.

[0085] For example, in one implementation, for reaching any target location, the following time optimal performance indicator function J may be selected:

[0086]

[0087] In the formula, t0 is the initial time point, t f is the time point when the target location is reached.

[0088] S130, constructing a corresponding Hamiltonian equation based on the motion model of the unmanned vehicle and the time-optimal performance index function, and determining the corresponding motion trajectory expression when the rotation angular velocity takes different extreme values ​​under the time-optimal condition with the goal of minimizing the Hamiltonian equation.

[0089] S140, determining the configuration composition of the time optimal motion trajectory of the unmanned vehicle with limited speed according to different motion trajectory expressions.

[0090] Among them, the Hamiltonian equation is mainly obtained by using the Hamiltonian-Jacobi theory transformation. The Hamiltonian-Jacobi equation (HJE) is a canonical transformation of the classical Hamiltonian. The result obtained by this transformation is a first-order nonlinear partial differential equation. For example, for the above-mentioned time optimal performance index function, the form transformation according to the form of the Hamiltonian equation can be obtained:

[0091]

[0092] Where η represents the current pose vector of the unmanned vehicle, which includes the current position x and the current orientation angle θ.

[0093] Furthermore, according to the motion model of the unmanned vehicle, the Hamiltonian equation can be expressed as follows:

[0094] H(λ, η)=λ1v cosθ+λ2v sinθ+λ3ω;

[0095] The corresponding adjoint equation can be expressed as:

[0096]

[0097] Where λ1 and λ2 are two constant scalars, which can be determined according to the corresponding coefficients in the above motion model, and λ3 is a variable.

[0098] Therefore, in order to minimize the Hamiltonian equation, according to the relationship between λ3 and 0, the rotation angular velocity ω can be expressed as the time optimal control quantity as follows:

[0099]

[0100] If the time variable t c After that, λ3=0 is always maintained, that is, ω * =0, then the corresponding time optimal motion trajectory can be expressed as follows:

[0101]

[0102] It can be seen that the time-optimal motion trajectory in this case is composed of line segments.

[0103] If the time variable t c After that, the sign of λ3 is always kept unchanged, that is, ω * =-ω max sign(λ3), then the corresponding time-optimal motion trajectory can be expressed as follows:

[0104]

[0105] According to the relationship between trigonometric functions, the above trajectory can be transformed into an expression of a circle:

[0106]

[0107] It can be seen that the time-optimal motion trajectory in this case is an arc. According to Dubins theory, under any condition of the terminal orientation, the time-optimal motion trajectory consists of line segments and arcs. Therefore, the configuration of the time-optimal motion trajectory of the unmanned vehicle with limited speed is There are four types:

[0108]

[0109] For example, when the target position point is located directly in front of the current direction of the unmanned vehicle, the time-optimal motion trajectory at this time is a line segment; when the target position point is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, or when the target position point is located directly behind the current direction of the unmanned vehicle, the time-optimal motion trajectory at this time is an arc to a line segment; when the target position point is located on the rotation circle of the unmanned vehicle, the time-optimal motion trajectory at this time is an arc; when the target position point is located inside the rotation circle of the unmanned vehicle, the time-optimal motion trajectory at this time is a line segment to an arc, etc.

[0110] Therefore, after obtaining all configurations of the time-optimal motion trajectory, this embodiment will introduce the concepts of switching points and switching angles, and on this basis design a time-optimal control law for unmanned vehicles with rotational angular velocity as a variable. Among them, the switching point is defined as the critical point where the time-optimal motion trajectory turns from a line segment to an arc or from an arc segment to a line segment. It can be understood that when the time-optimal motion trajectory is only a line segment, the switching point is defined as the current position x of the unmanned vehicle; when the time-optimal motion trajectory is only an arc, the switching point is defined as the target position. The switching angle is defined as the angle between the current orientation of the unmanned vehicle and the line connecting the initial point of the arc segment and the terminal point of the arc segment.

[0111] In one embodiment, Figure 2As shown, the above-mentioned time optimal control law is obtained by pre-construction, which specifically includes steps S210 to S240:

[0112] S210, determining the rotation radius of the unmanned vehicle according to the running speed and the maximum rotation angular velocity, and determining the expression of the rotation center of the unmanned vehicle in combination with the relative relationship between the current posture of the unmanned vehicle and the arbitrary target position.

[0113] In order to characterize the relative relationship between the current position of the unmanned vehicle and the target position, the unit vector of the current orientation of the unmanned vehicle is defined as e, e = [cosθ sinθ] T ; and define the unit vector from the current position of the unmanned vehicle to any target position as e f , e f =(x f -x) / ||x f -x||, where x f =[x f y f ] T is the target position. Therefore, according to the running speed v and the maximum rotation angular velocity ω of the unmanned vehicle max , we can define the rotation radius r of the unmanned vehicle's rotation circle, r = v / ω max .

[0114] Considering the different orientation information of the target position relative to the current position of the unmanned vehicle, if the target position is on the right side of the current position of the unmanned vehicle, that is, e×e f <0, the unmanned vehicle will rotate to the right; conversely, if the target position is to the left of the current position of the unmanned vehicle, that is, e×e f > 0, the unmanned vehicle will turn left. Therefore, when e×e f ≠0, the rotation center x selected by the unmanned vehicle c It can be expressed as:

[0115]

[0116] S220, based on the current position, rotation radius and rotation center of the unmanned vehicle, determine the expression of the switching point when the unmanned vehicle reaches any target position from the current position in each configuration.

[0117] Therefore, according to the above four configurations, the switching points are calculated respectively. Specifically, the calculation method of the switching points is as follows:

[0118] (1) When the time-optimal motion trajectory is a line segment, the relative relationship between the current position of the unmanned vehicle and the target position is e×e f =0,e T e f≥0, that is, the target position is just in front of the current direction of the unmanned vehicle. Therefore, according to the definition of the switching point, in this case the switching point x t It can be expressed as:

[0119] x t =xe×e f =0,e T e f ≥0;

[0120] (2) When the time-optimal motion trajectory is a circular arc turning line segment, there are two cases. The first case is when the target position is not colinear with the current position of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, that is, e×e f ≠0,||x f -x c ||>r; The second is when the target position is exactly behind the current direction of the unmanned vehicle, that is, e×e f =0,e T e f <0, for these two cases, the following calculations will be performed respectively:

[0121] like Figure 3 As shown in (a) and (b), in the first case, since the target position x f In x c is the outside of the rotating circle with the center as the circle, then there are two optional tangent points, denoted by x b，1 and x b，2 , if we define f To the center of rotation x c The distance is d, d = ||x c -x f ||; Define the distance from the target position to the optional tangent point as d t , Therefore, according to the principle of geometric rotation, we can get x b，1 and x b，1 The expression is as follows:

[0122]

[0123] Therefore, in order to reach the target position, when the unmanned vehicle needs to turn left, that is, e×e f > 0, then the tangent point x should be selected b，1 As the switching point x t ; When the unmanned vehicle needs to turn right, that is, e×e f <0, then the tangent point x should be selected b，2 As the switching point x t . At this time, it can be expressed by the following formula:

[0124]

[0125] like Figure 3 As shown in (c), in the second case, the target position is just behind the current direction of the unmanned vehicle. There are two time-optimal motion trajectories, and the shortest time to reach the target position is exactly the same. In order to ensure the uniqueness of the time-optimal motion trajectory, in this case, the unmanned vehicle is defined to rotate left by default. At this time, the tangent point x should be selected. b，1 As the switching point x t Therefore, according to the definition of the switching point, it can be expressed by the following formula:

[0126]

[0127] (3) When the optimal motion trajectory is an arc, the relative relationship between the current position of the unmanned vehicle and the target position is e×e f ≠0,||x f -x c ||=r, that is, the target position is exactly on the rotation circle of the unmanned vehicle. Therefore, according to the definition of the switching point, it can be expressed by the following formula:

[0128] x t =x f e×e f ≠0,||x f -x c ||=r.

[0129] (4) When the optimal time trajectory is a line segment turning into an arc, the relative relationship between the current position of the unmanned vehicle and the target position is e×e f ≠0,||x f -x c ||<r, that is, the unmanned vehicle moves from the current position x to the switching point x through the line segment t Then, from the switching point x t Move to the target position x through the arc segment f ,like Figure 4 As shown in (a) and (b) in . If the length of the unmanned vehicle moving in the straight line segment is defined as L, according to the geometric relationship, the moving length L of the line segment can be expressed as:

[0130]

[0131] Therefore, according to the definition of the switching point, it can be expressed by the following formula:

[0132]

[0133] In summary, the switching point x t It can be expressed as:

[0134]

[0135] S230, based on the current heading angle and the switching point of the unmanned vehicle, determine an expression for the switching angle when the unmanned vehicle reaches any target position from the current position in each configuration.

[0136] After the switching point is calculated, the switching angles in the corresponding cases are calculated according to the above four configurations. Specifically, the calculation method of the switching angle is as follows:

[0137] (1) When the time-optimal motion trajectory is a line segment, that is, e×e f =0,e T e f ≥0, the direction of the unmanned vehicle does not change during this process, that is, the initial point of the arc segment coincides with the terminal point, which is the current position of the unmanned vehicle. Therefore, according to the definition of the switching angle, in this case β can be expressed as:

[0138] β=0 e×e f =0,e T e f ≥0.

[0139] (2) When the optimal time trajectory is a circular arc turning into a line segment, that is, e×e f ≠0,||x f -x c ||>r or e×e f =0,e T e f <0, the unmanned vehicle first rotates from the current position to the switching point, and then moves to the target position through a straight line. The initial point of the arc segment is the current position of the unmanned vehicle, and the terminal point of the arc segment is the switching point. Therefore, according to the definition of the switching angle, in this case β can be expressed as:

[0140] e×e f ≠0,||x f -x c ||>r or e×e f =0,e T e f <0.

[0141] (3) When the time-optimal motion trajectory is a circular arc, that is, e×e f ≠0,||x f -x c ||=r, the unmanned vehicle rotates directly from the current position to the target position x f , the initial point of the arc segment is the current position x of the unmanned vehicle, and the terminal point of the arc segment is the target position x f , which is also the switching point xt Therefore, according to the definition of the switching angle, β in this case can be expressed as:

[0142]

[0143] (4) When the optimal time trajectory is a line segment turning into a circular arc, that is, e×e f ≠0,||x f -x c ||<r, the unmanned vehicle first starts the line segment motion from the current posture to the switching point, and then moves to the target position x by rotation. f The initial point of the arc segment is the switching point x t , the terminal point of the arc segment is the target position x f Therefore, according to the definition of the switching angle, β in this case can be expressed as:

[0144]

[0145] In summary, the switching angle β is expressed as follows:

[0146]

[0147] S240, based on the switching angle and the maximum rotational angular velocity, construct an expression for the optimal control law of the time for the unmanned vehicle to reach the terminal direction under any conditions from the current position in each configuration with the rotational angular velocity as a variable.

[0148] After calculating the switching angle, this embodiment will design a time-optimal control law under any terminal orientation condition based on the switching point and the switching angle, and then use the time-optimal control law to control the rotational angular velocity of the unmanned vehicle so that it reaches the target position with optimal time.

[0149] Similarly, according to the above four configurations, the corresponding time optimal control laws are designed respectively. Specifically, the design method of the time optimal control law is as follows:

[0150] (1) When the time-optimal motion trajectory is a line segment, the current orientation angle θ of the unmanned vehicle remains constant during this process. Therefore, the time-optimal control law ω in this case is * It can be expressed as:

[0151] ω * =0 e×e f =0,e T e f ≥0.

[0152] (2) When the optimal time trajectory is a circular arc to a line segment, the time required for the unmanned vehicle to move in the circular arc segment is the ratio of the movement direction change angle γ to the maximum rotation angular velocity, and then the line segment moves to the target position xf .like Figure 5 As shown in (a) to (d), since the current position x of the unmanned vehicle is different from the switching point x t are two tangent points of a point outside the rotating circle. Therefore, according to the principle of equal base angles of isosceles triangles, when the switching angle When the motion changes towards the angle When switching angle When the motion changes towards the angle Therefore, the unmanned vehicle's motion direction changes in the arc segment by an angle γ = 2β. When the target position is to the right of the unmanned vehicle's current position, the unmanned vehicle rotates to the right in the arc segment, that is, -ω is selected. max ; When the target position is to the left of the current position of the unmanned vehicle, the unmanned vehicle rotates to the left in the arc segment, that is, choose +ω max When the target position is just behind the current direction of the unmanned vehicle, the unmanned vehicle will rotate left by default in the arc segment, that is, choose +ω max Therefore, in this case, the time optimal control law ω * It can be expressed as:

[0153]

[0154]

[0155] (3) When the optimal time trajectory is an arc, when the target position is to the right of the current position of the unmanned vehicle, the unmanned vehicle rotates to the right, that is, -ω is selected max ; When the target position is to the left of the current position of the unmanned vehicle, the unmanned vehicle rotates to the left, i.e., choose +ω max Therefore, in this case, the time optimal control law ω * It can be expressed as:

[0156] ω * =sign(e×e f )ωmax e×e f ≠0,||x f -x c ||=r.

[0157] (4) When the time-optimal motion trajectory is a line segment turning into an arc, the time required for the unmanned vehicle to move in the straight segment is the ratio of the motion length L to the running speed v, and then rotate to the target position x f Similarly, in this case, the time optimal control law ω * It can be expressed as:

[0158]

[0159] In summary, the time optimal control law ω *The representation is as follows:

[0160]

[0161] Therefore, according to the above four configurations and the corresponding designed time optimal control law, all target positions that the unmanned vehicle can reach can be calculated under any given movement duration T.

[0162] (1) When the time-optimal motion trajectory is a line segment, the target position x that the unmanned vehicle can reach is f for:

[0163] x f =x+vTe;

[0164] (2) When the time-optimal motion trajectory is a circular arc turning line segment, the time-optimal control law ω * First, at t0≤t≤t c The time period is set to -ω max or +ω max , then at t c <t≤t f The time period is set to 0, where the switching time t0 is the initial time point when the unmanned vehicle is at its current position, t f is the time point when the target position is reached. At this time, the target position x that the unmanned vehicle can reach f for:

[0165]

[0166] in,

[0167] In the formula, is the rotation matrix with the switching angle as the independent variable.

[0168] Since the angle of motion change in the arc segment is 0<γ<2π, the switching angle should satisfy 0<β<π; at the same time, at a given motion duration T, the switching angle should also satisfy When the arc segment rotates left or right, it is also necessary to satisfy r sinβ+(vT-2βr)cosβ>0. Therefore, the switching angle β should satisfy the following constraints:

[0169]

[0170] (3) When the time-optimal motion trajectory is an arc, the time-optimal control law ω * Always set to -ω max or +ω max At this point, the target position x that the unmanned vehicle can reach is f for:

[0171]

[0172] As above, at this time, the switching angle β should satisfy the following constraints:

[0173]

[0174] (4) When the time-optimal motion trajectory is a line segment turning into a circular arc, the time-optimal control law ω * First, at t0≤t≤t c is set to 0 during the time period, and then at t c <t≤t f The time period is set to -ω max or +ω max , where the switching time At this time, the target position x that the unmanned vehicle can reach f for:

[0175]

[0176] like Figure 4 As shown in (a) and (b) in the figure, since the projection point x′ of the target position on the rotating circle f , is defined along the -e direction, which means that the motion direction of the arc segment changes at an angle π<γ<2π, so the switching angle should satisfy like Figure 6 As shown in the figure, given a certain switching angle β, the upper limit d of the distance that the unmanned vehicle can translate on the straight line segment is c It can be expressed as:

[0177]

[0178] Considering this situation, the running time of the unmanned vehicle in the straight section should meet The switching angle should also meet At this time, the switching angle β should satisfy the following constraints:

[0179]

[0180] Finally, when calculating the isochrone, multiple sets of motion durations T are given at the same time, and the constraints corresponding to the switching angle β under the four time-optimal motion trajectory configurations are calculated respectively, and then all feasible target positions are calculated. Then, all target positions corresponding to the multiple sets of motion durations T are processed as a union to obtain a set, which can be used as the isochrone of the time-optimal motion of the unmanned vehicle.

[0181] Based on the above isochrone calculation method, this embodiment proposes a motion control method for an unmanned vehicle with limited speed. Figure 7 As shown, the unmanned vehicle control method includes steps S310 to S350:

[0182] S310, obtaining current motion information of the unmanned vehicle with limited rotation speed, wherein the motion information includes a current position and a current orientation angle of the unmanned vehicle.

[0183] S320, according to the motion characteristic information of the unmanned vehicle and the given motion duration, setting the constraint conditions of the switching angle of the unmanned vehicle under the optimal motion trajectory configuration at the corresponding time.

[0184] It can be understood that the constraint conditions on the switching angle are related to the given movement duration. For details, please refer to the above description of the constraint conditions on the switching angle under different configurations, which will not be repeated here.

[0185] S330, using the pre-constructed time-optimal control law and the constraints under different time-optimal motion trajectory configurations, respectively calculate the target position that the unmanned vehicle can reach from the current position under the current orientation state under each configuration.

[0186] S340, taking the set of all target positions under all configurations as the isochrone of the unmanned vehicle in the case of time-optimal motion.

[0187] According to the time optimal control law under each configuration designed based on the above method, combined with the constraint condition of the switching angle, the corresponding target position can be calculated. For details, please refer to the calculation formula of the target position mentioned above. Then, all the target positions under all configurations are processed as a union, and the connection line of these target positions is the motion isochrone of the unmanned vehicle under the time optimal condition.

[0188] S350: Control the unmanned vehicle to perform corresponding movement according to the isochrone line.

[0189] Finally, the calculated isochrones are used to perform corresponding motion control such as motion planning and vehicle scheduling to meet the needs of actual application scenarios.

[0190] In order to verify the real-time solution method of isochrones in the above embodiment, a simulation is performed with an unmanned vehicle having a running speed of 1 m / s and a maximum rotation angular velocity of 1 rad / s. Under the condition of a given running time T = 5 s, the isochrones that the unmanned vehicle can reach are calculated according to the above method as follows: Figure 8 Then, multiple groups of running time T = {3s4s 5s 6s 7s} are given respectively, and the current position x = [0 0] T , current heading angle For different exercise durations T i , where i = 1, 2, 3, 4, 5, repeat the above steps of calculating the target position 5 times, Fig. 9 The isochrones that the unmanned vehicle can reach after moving for 3s, 4s, 5s, 6s, and 7s respectively are given.

[0191] The control method for the unmanned vehicle with limited speed of this embodiment can solve the problem of isochrone calculation under the time-optimal motion condition of the unmanned vehicle with limited speed according to the current position and motion duration of the unmanned vehicle, and can provide a new idea for the time-optimal motion mechanism of the unmanned vehicle with limited speed, and can also provide the best strategy for tasks in various occasions such as motion planning, vehicle scheduling and accessibility analysis of the unmanned vehicle. In addition, the control method of this embodiment can also be transferred to other types of robots that meet the description of the motion model, and the isochrone information of the robot under the condition of limited speed can be obtained in real time, so as to facilitate motion control thereof.

[0192] Please refer to Fig.10 Based on the method of the above embodiment, this embodiment proposes a speed-limited unmanned vehicle control device 100. Exemplarily, the speed-limited unmanned vehicle control device 100 includes:

[0193] The information acquisition module 110 is used to obtain the current motion information of the unmanned vehicle with limited speed, and the motion information includes the current position and current heading angle of the unmanned vehicle.

[0194] The constraint setting module 120 is used to set the constraint conditions of the switching angle of the unmanned vehicle under the optimal motion trajectory configuration at the corresponding time according to the motion characteristic information of the unmanned vehicle and the given motion duration.

[0195] The calculation module 130 is used to use the pre-constructed time-optimal control law and the constraints under different time-optimal motion trajectory configurations to calculate the target positions that the unmanned vehicle can reach from the current position under the current heading angle under each configuration, and use the set of all target positions under all configurations as the isochrone of the unmanned vehicle under the time-optimal motion condition.

[0196] The control module 140 is used to control the unmanned vehicle to perform corresponding movements according to the isochrone.

[0197] It can be understood that the device of this embodiment corresponds to the method of the above embodiment, and the options in the above embodiment are also applicable to this embodiment, so they will not be described repeatedly here.

[0198] The present application also provides an unmanned vehicle. Exemplarily, the unmanned vehicle includes a processor and a memory, wherein the memory stores a computer program, and the processor runs the computer program to enable the unmanned vehicle to execute the functions of each module in the above-mentioned unmanned vehicle control method for limited speed or the above-mentioned unmanned vehicle control device for limited speed.

[0199] The present application also provides a readable storage medium for storing the computer program used in the above-mentioned unmanned vehicle.

[0200] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0201] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0202] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0203] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A speed-limited unmanned vehicle control method, characterized in that: include: Acquire current motion information of the unmanned vehicle with limited speed, wherein the current motion information includes a current position and a current heading angle of the unmanned vehicle; According to the motion characteristic information of the unmanned vehicle and the given motion duration, setting the constraint condition of the switching angle of the unmanned vehicle under the optimal motion trajectory configuration at the corresponding time, wherein the motion characteristic information includes the maximum rotation angular velocity and the running speed of the unmanned vehicle; Using the pre-constructed time-optimal control law and the constraint conditions under different time-optimal motion trajectory configurations, respectively calculate the target position that the unmanned vehicle can reach from the current position under the current orientation angle under each configuration; The set of all target positions in all configurations is taken as the isochrone of the unmanned vehicle in the case of time-optimal motion; Controlling the unmanned vehicle to move accordingly according to the isochrone; The configuration of the time-optimal motion trajectory of the unmanned vehicle includes a line segment, an arc to a line segment, an arc, and a line segment to an arc; the construction process of the time-optimal control law under each time-optimal motion trajectory configuration includes: Determine the rotation radius of the unmanned vehicle according to the running speed and the maximum rotation angular velocity, and determine the expression of the rotation center of the unmanned vehicle in combination with the relative relationship between the current posture of the unmanned vehicle and any target position; Based on the current position of the unmanned vehicle, the rotation radius and the rotation center, determine an expression for a switching point when the unmanned vehicle reaches any target position from the current position in each configuration, wherein the switching point is defined as a critical point where the time-optimal motion trajectory switches from a line segment to an arc segment or from an arc segment to a line segment; Based on the current orientation angle of the unmanned vehicle and the switching point, determine an expression for the switching angle when the unmanned vehicle reaches any target position from the current position in each configuration, wherein the switching angle is defined as the angle between the current orientation angle of the unmanned vehicle and a line connecting the initial point of the arc segment and the terminal point of the arc segment; Based on the switching angle and the maximum rotational angular velocity, an optimal control law for the time for the unmanned vehicle to reach the terminal direction from the current position under any conditions in each configuration is constructed with the rotational angular velocity as a variable.

2. The speed-limited unmanned vehicle control method according to claim 1, characterized in that: The four configurations of the time-optimal motion trajectory of the unmanned vehicle are obtained by predetermination, including: Constructing a motion model related to current motion information of the unmanned vehicle; Taking the optimal time for the unmanned vehicle to reach the target position from the current position as the goal, selecting the time optimal performance index function that satisfies the maximum rotation angular velocity constraint; According to the motion model of the unmanned vehicle and the time-optimal performance index function, a corresponding Hamiltonian equation is constructed, and with the goal of minimizing the Hamiltonian equation, a corresponding motion trajectory expression when the rotation angular velocity takes different extreme values ​​under the time-optimal condition is determined; According to different motion trajectory expressions, the configuration composition of the time optimal motion trajectory of the unmanned vehicle with limited speed is determined.

3. The speed-limited unmanned vehicle control method according to claim 1, characterized in that: The configurations of the time-optimal motion trajectory of the unmanned vehicle include four types: line segment, arc to line segment, arc, and line segment to arc. The various configurations and the motion state of the unmanned vehicle satisfy the following relationship: When the target position point is located directly in front of the current direction of the unmanned vehicle, the time optimal motion trajectory is a line segment; When the target position point is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, or when the target position point is directly behind the current orientation of the unmanned vehicle, the time optimal motion trajectory is an arc turning line segment; When the target position point is located on the rotation circle of the unmanned vehicle, the time-optimal motion trajectory is an arc; When the target position point is located inside the rotating circle of the unmanned vehicle, the time-optimal motion trajectory is a line segment turning into an arc.

4. The speed-limited unmanned vehicle control method according to claim 1, characterized in that: The switching point is calculated as follows: When the time-optimal motion trajectory is a line segment, the current position of the unmanned vehicle is used as the switching point at this time; When the time optimal motion trajectory is an arc turning line segment, when the target position is directly behind the current orientation of the unmanned vehicle, the switching point at this time is calculated according to the first formula; when the target position is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, the switching point at this time is calculated according to the second formula; When the time-optimal motion trajectory is an arc, the target position of the unmanned vehicle is used as the switching point at this time; When the time-optimal motion trajectory is a line segment turning into an arc, the switching point at this time is calculated according to the third formula based on the current position of the unmanned vehicle and the length of the unmanned vehicle moving in a straight line; The first formula, the second formula and the third formula are respectively: ； ； ； In the formula, , and The switching points calculated using the first formula, the second formula, and the third formula may be represented in sequence; is the current position of the unmanned vehicle; is any target position; From the target position to the center of the rotation circle The distance ; is the distance from the target position to the switching point; is the unit vector of the current orientation of the unmanned vehicle; is a unit vector pointing from the current position to the target position; is the rotation radius of the unmanned vehicle, where is the maximum rotation angular velocity, is the running speed of the unmanned vehicle; is the length of the unmanned vehicle moving in a straight line; Represents a symbolic function.

5. The speed-limited unmanned vehicle control method according to claim 1, characterized in that: The switching angle is calculated as follows: When the time optimal motion trajectory is a line segment, the switching angle is zero; When the time-optimal motion trajectory is an arc or an arc-to-line segment, the switching angle at this time is calculated according to the current position of the unmanned vehicle, the unit vector of the current orientation and the switching point; When the time-optimal motion trajectory is a line segment turning into a circular arc, the switching angle at this time is calculated according to the target position of the unmanned vehicle, the unit vector of the current orientation and the switching point.

6. The speed-limited unmanned vehicle control method according to claim 4, characterized in that: The construction of the time optimal control law of the unmanned vehicle includes: When the time-optimal motion trajectory is a line segment, the time-optimal control law is set to zero; When the time-optimal motion trajectory is an arc-turned line segment, when the target position is directly behind the current orientation of the unmanned vehicle, the first piecewise function is selected as the time-optimal control law; when the target position is not colinear with the current posture of the unmanned vehicle and is outside the rotation circle of the unmanned vehicle, the second piecewise function is selected as the time-optimal control law; When the time-optimal motion trajectory is an arc, when the target position is located on the right side of the current posture of the unmanned vehicle, the time-optimal control law is set to a negative maximum rotation angular velocity; when the target position is located on the left side of the current posture of the unmanned vehicle, it is set to a positive maximum rotation angular velocity; When the time-optimal motion trajectory is a line segment turning into a circular arc, a third piecewise function is selected as the time-optimal control law; The first piecewise function, the second piecewise function and the third piecewise function are respectively: ； ； ； In the formula, , and denote the time optimal control laws represented by the first piecewise function, the second piecewise function and the third piecewise function respectively; is the time variable of the unmanned vehicle movement, is the initial time point, is the time point of reaching the target location; is the switching angle.

7. A speed-limited unmanned vehicle control device, characterized in that: include: An information acquisition module, used to acquire current motion information of the unmanned vehicle with limited speed, wherein the current motion information includes a current position and a current orientation angle of the unmanned vehicle; A constraint setting module, used to set the constraint conditions of the switching angle of the unmanned vehicle under the optimal motion trajectory configuration at the corresponding time according to the motion characteristic information of the unmanned vehicle and a given motion duration, wherein the motion characteristic information includes the maximum rotation angular velocity and running speed of the unmanned vehicle; A calculation module, for calculating the target position that the unmanned vehicle can reach from the current position in each configuration by using the pre-constructed time-optimal control law and the constraint conditions in different time-optimal motion trajectory configurations, and taking the set of all target positions in all configurations as the isochrone of the unmanned vehicle in the time-optimal motion condition; A control module, used for controlling the unmanned vehicle to move accordingly according to the isochrone; The configuration of the time-optimal motion trajectory of the unmanned vehicle includes a line segment, an arc to a line segment, an arc, and a line segment to an arc; the construction process of the time-optimal control law under each time-optimal motion trajectory configuration includes: Determine the rotation radius of the unmanned vehicle according to the running speed and the maximum rotation angular velocity, and determine the expression of the rotation center of the unmanned vehicle in combination with the relative relationship between the current posture of the unmanned vehicle and any target position; Based on the current position of the unmanned vehicle, the rotation radius and the rotation center, determine an expression for a switching point when the unmanned vehicle reaches any target position from the current position in each configuration, wherein the switching point is defined as a critical point where the time-optimal motion trajectory switches from a line segment to an arc segment or from an arc segment to a line segment; Based on the current orientation angle of the unmanned vehicle and the switching point, determine an expression for the switching angle when the unmanned vehicle reaches any target position from the current position in each configuration, wherein the switching angle is defined as the angle between the current orientation angle of the unmanned vehicle and a line connecting the initial point of the arc segment and the terminal point of the arc segment; Based on the switching angle and the maximum rotational angular velocity, an optimal control law for the time for the unmanned vehicle to reach the terminal direction from the current position under any conditions in each configuration is constructed with the rotational angular velocity as a variable.

8. An unmanned vehicle, characterized in that: The unmanned vehicle comprises a processor and a memory, the memory stores a computer program, and the processor is used to execute the computer program to implement the speed-limited unmanned vehicle control method according to any one of claims 1 to 6.

9. A readable storage medium, characterized in that: The device stores a computer program, which, when executed on a processor, implements the speed-limited unmanned vehicle control method according to any one of claims 1 to 6.

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