Event-triggered adaptive trajectory tracking control method for wheeled mobile robot

Abstract

The invention discloses an event-triggered adaptive trajectory tracking control method for a wheeled mobile robot, belongs to the technical field of robots, and aims to solve the problem that the conventional control method assumes that the wheeled mobile robot periodically transmits a control instruction to an execution mechanism in the trajectory tracking process, so that the trajectory tracking accuracy is poor. In order to solve the problem that the sampling time interval of the wheeled mobile robot is usually set to be smaller so as to obtain higher control precision, but the information transmission burden of the wheeled mobile robot is also greatly increased, the method comprises the following steps of: solving the problem that the information transmission burden of the wheeled mobile robot is greatly increased; according to the event-triggered adaptive trajectory tracking control method for the wheeled mobile robot, a kinematics controller and a dynamics controller are included, the kinematics controller can ensure that the position and posture tracking error of the wheeled mobile robot is gradually converged to zero, and the kinematics controller can ensure that the position and posture tracking error of the wheeled mobile robot is gradually converged to zero; the dynamic controller can ensure that the speed and angular speed tracking errors of the wheeled mobile robot converge to be in a neighborhood of zero within fixed time and effectively avoid the occurrence of a sesame phenomenon.

Description

Technical Field

[0001] The present invention belongs to the technical field of robots, and particularly relates to an event-triggered adaptive trajectory tracking control method for a wheeled mobile robot. Background Art

[0002] Wheeled mobile robots have the advantages of good flexibility, high reliability, strong load capacity, simple structure, etc., and have been widely used in the fields of logistics transportation, power grid inspection, disaster relief, etc. in recent years. However, the dynamic model of a wheeled mobile robot has the characteristics of high nonlinearity, strong coupling, multi-input multi-output, and nonholonomic constraints. In addition, due to the complex working environment, the wheeled mobile robot is inevitably affected by model uncertainties and external disturbances during the task execution process. These factors greatly increase the design difficulty of the control system of the wheeled mobile robot.

[0003] In the process of trajectory tracking by traditional control methods, it is assumed that the wheeled mobile robot periodically transmits control instructions to the actuator. The sampling time interval of the wheeled mobile robot is usually set to be small in order to obtain high control accuracy. However, this also greatly increases the information transmission burden of the wheeled mobile robot. The event-triggered control method well overcomes this shortcoming. The control instruction is updated only when the pre-given event-triggering condition is satisfied, thereby reducing the update frequency of the control instruction and saving the information transmission resources of the wheeled mobile robot. The prior art [1] (see: Liu Benyou, Ai Zidong. Nonholonomic robot trajectory tracking based on adaptive event triggering [J]. Machine Tool & Hydraulics, 2022, 51(15): 15-20.) designed an event-triggered control method for the trajectory tracking problem of a wheeled mobile robot. However, this event-triggered control method only stays at the level of the kinematic controller design and does not further expand to the level of the dynamic controller design. For this reason, we propose an event-triggered adaptive trajectory tracking control method for a wheeled mobile robot. Summary of the Invention

[0004] The technical problem to be solved by the event-triggered adaptive trajectory tracking control method for a wheeled mobile robot disclosed by the present invention is to achieve high-precision trajectory tracking control of the wheeled mobile robot under the consideration of model uncertainties and external disturbances, and has the following advantages:

[0005] (1) The present invention consists of two parts: a kinematic controller and a dynamic controller. The kinematic controller can ensure that the position and attitude tracking errors of the wheeled mobile robot asymptotically converge to zero, and the dynamic controller can ensure that the speed and angular velocity tracking errors of the wheeled mobile robot converge to a neighborhood of zero within a fixed time and effectively avoid the occurrence of the Zeno phenomenon.

[0006] (2) The dynamic controller of the present invention is designed based on the fixed-time adaptive control method. The upper bound of the lumped uncertainties is estimated by using the parameter adaptive technique. The controller has strong robustness against model uncertainties and external disturbances.

[0007] (3) During the design process of the dynamic controller, an event-triggering mechanism is introduced. The control command is updated only when the pre-given event-triggering condition is satisfied, thereby reducing the update frequency of the control command and saving the information transmission resources of the wheeled mobile robot.

[0008] To achieve the above object, the present invention provides the following technical solution: An event-triggered adaptive trajectory tracking control method for a wheeled mobile robot. First, the kinematic and dynamic models of the mobile robot are established; then, based on the kinematic model of the wheeled mobile robot, a kinematic controller is designed; finally, based on the dynamic model of the wheeled mobile robot, a dynamic controller is designed.

[0009] An event-triggered adaptive trajectory tracking control method for a wheeled mobile robot disclosed by the present invention consists of two parts: a kinematic controller and a dynamic controller. The kinematic controller can ensure that the position and attitude tracking errors of the wheeled mobile robot asymptotically converge to zero. The dynamic controller can ensure that the speed and angular velocity tracking errors of the wheeled mobile robot converge to a neighborhood of zero within a fixed time and effectively avoid the occurrence of Zeno phenomenon.

[0010] The dynamic controller is designed based on the fixed-time adaptive control method. The upper bound of the lumped uncertainties is estimated by using the parameter adaptive technique. The controller has strong robustness against model uncertainties and external disturbances. In addition, during the design process of the dynamic controller, an event-triggering mechanism is introduced. The control command is updated only when the pre-given event-triggering condition is satisfied, thereby reducing the update frequency of the control command and saving the information transmission resources of the wheeled mobile robot, with obvious advantages.

[0011] An event-triggered adaptive trajectory tracking control method for a wheeled mobile robot disclosed by the present invention includes the following steps:

[0012] Step 1: Establish the kinematic and dynamic models of the mobile robot.

[0013] The structure of the wheeled mobile robot is as Figure 1 shown. Its front wheels are auxiliary wheels, and the two rear wheels are driving wheels with a driving wheel radius of r. Assume that the center of mass of the wheeled mobile robot coincides with the geometric center, and an inertial coordinate system O r X r Y r and a body coordinate system O b X b Y bDescribe the planar motion of a wheeled mobile robot. The mass and moment of inertia of the wheeled mobile robot are \(m\) and \(I\) respectively, and the distance between the driving wheel and the geometric center is \(l\). Without considering slipping and skidding, the kinematic equation of the wheeled mobile robot is

[0014]

[0015] where \(q = [x, y, \theta]\) T is the position and orientation of the wheeled mobile robot, \(\zeta = [v, \omega]\) T is the velocity and angular velocity of the wheeled mobile robot, \(J(q)\in\) 3×2 is the velocity transformation matrix, and the non - holonomic constraint of the wheeled mobile robot can be described as The dynamic equation of the wheeled mobile robot is

[0016]

[0017] where \(M(q)\in\) 3×3 is the inertia matrix, is the centripetal and Coriolis force matrix, \(G(q)\in\) 3 is the gravity vector, \(B(q)\in\) 3×2 is the input transformation matrix, \(\tau\in\) 2 is the control torque, \(d\in\) 3 is the external disturbance, \(A\) T (q)\in\) 3 is the non - holonomic constraint vector, \(\lambda\) is the Lagrange multiplier, and their specific expressions are respectively G(q)=0 3 ,

[0018] The model uncertainty is considered as \(M(q)=M\) 0 (q)+M Δ (q), where \(M\) 0 (q) and \(M\) Δ (q) represent the nominal part and the uncertain part respectively.

[0019] Taking the derivative of Equation (1) with respect to time, we can get

[0020]

[0021] Substituting Equation (3) into Equation (2) and applying the relation \(J\) T (q)A T (q)=0 2 We can get

[0022]

[0023] where \(H=(J\) T(q)M 0 (q)J(q)) -1 J T (q)B(q), represents the lumped uncertainty term. Assume that the lumped uncertainty term δ is bounded, i.e., there exists an unknown constant B > 0 such that δ i ≤ B, i = 1, 2.

[0024] Step 2: Based on the kinematic model of the wheeled mobile robot, design a kinematic controller.

[0025] First, design a kinematic controller to enable the wheeled mobile robot's position and attitude to track the desired position and attitude. The desired trajectory of the wheeled mobile robot is given as

[0026]

[0027] Define the position and attitude tracking errors of the wheeled mobile robot:

[0028]

[0029] Then the kinematic error equation of the wheeled mobile robot can be expressed as

[0030]

[0031] The kinematic controller of the wheeled mobile robot is designed as

[0032]

[0033] where h 1 > 0, h 2 > 0, h 3 > 0, v c and ω c are the virtual linear velocity and angular velocity.

[0034] Considering the wheeled mobile robot system described by Eqs. (1) and (2), under the action of the kinematic controller (8), the position and attitude tracking errors of the wheeled mobile robot can asymptotically converge to zero.

[0035] Step 3: Based on the dynamic model of the wheeled mobile robot, design a dynamic controller.

[0036] Then, design a dynamic controller to enable the wheeled mobile robot's linear velocity and angular velocity to track the virtual linear velocity and angular velocity. Define the linear velocity and angular velocity tracking errors of the wheeled mobile robot:

[0037]

[0038] Then the dynamic error equation of the wheeled mobile robot can be expressed as

[0039]

[0040] The event-triggered fixed-time adaptive controller is designed as

[0041]

[0042]

[0043]

[0044] where 0 < α < 1, β > 1, k 1 > 0, k 2 > 0, λ 1 > 0, λ 2 > 0, λ = [λ 1 , λ 2 T , ε > 0, E(t) = τ(t) - u(t) represents the control command measurement error, and represent two adjacent control command trigger times, represents the estimated value of B. For a given vector x ∈ n and scalar p ∈, the symbol sig p (·) is defined as sig p (x) = [sig p (x 1 ), sig p (x 2 ), …, sig p (x n )] T , where sig p (x i ) = x i p sgn(x i ), and the symbol tanh(·) is defined as tanh(x) = [tanh(x 1 ), tanh(x 2 ), …, tanh(x n )] T . In addition, the parameter adaptation law is selected as

[0045]

[0046] where η 1 > 0, η 2 > 0, η 3 ​> 0. The event trigger controller (11) updates the control instruction only when the event trigger condition (12) is satisfied, thereby reducing the information transmission between the wheeled mobile robot control system and the actuator and saving more information transmission resources.

[0047] Considering the wheeled mobile robot system described by equations (1) and (2), under the action of the event-triggered fixed-time adaptive controller (11) and the parameter adaptive law (14), the position and attitude tracking errors of the wheeled mobile robot can asymptotically converge to zero and no Zeno phenomenon occurs.

[0048] Compared with the prior art, the wheeled mobile robot event-triggered adaptive trajectory tracking control method provided by the present invention has at least the following beneficial effects:

[0049] (1) A wheeled mobile robot event-triggered adaptive trajectory tracking control method disclosed by the present invention consists of a kinematic controller and a dynamic controller. The kinematic controller can ensure that the position and attitude tracking errors of the wheeled mobile robot asymptotically converge to zero, and the dynamic controller can ensure that the speed and angular velocity tracking errors of the wheeled mobile robot converge to a neighborhood of zero within a fixed time and effectively avoid the occurrence of the Zeno phenomenon;

[0050] (2) A wheeled mobile robot event-triggered adaptive trajectory tracking control method disclosed by the present invention. The dynamic controller is designed based on the fixed-time adaptive control method, and the parameter adaptive technology is used to estimate the upper bound of the lumped uncertain terms. The controller has strong robustness to model uncertainties and external disturbances;

[0051] (3) A wheeled mobile robot event-triggered adaptive trajectory tracking control method disclosed by the present invention. During the design process of the dynamic controller, an event trigger mechanism is introduced. The control instruction is updated only when a pre-given event trigger condition is satisfied, thereby reducing the update frequency of the control instruction and saving the information transmission resources of the wheeled mobile robot;

[0052] (4) A wheeled mobile robot event-triggered adaptive trajectory tracking control method disclosed by the present invention. The controller is easy to implement, consumes few resources, has good tracking performance, is applicable to tasks such as logistics transportation, power grid inspection, and disaster relief, and has a wide application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a schematic structural diagram of the wheeled mobile robot in the embodiment of the present invention;

[0054] Figure 2 is a control block diagram of a wheeled mobile robot event-triggered adaptive trajectory tracking control method in the embodiment of the present invention;

[0055] Figure 3 It is a schematic diagram of the simulation result of the planar trajectory tracking of the wheeled mobile robot in the embodiment of the present invention;

[0056] Figure 4 It is a schematic diagram of the simulation result of the position and attitude tracking error of the wheeled mobile robot in the embodiment of the present invention;

[0057] Figure 5 It is a schematic diagram of the simulation result of the speed and angular velocity tracking error of the wheeled mobile robot in the embodiment of the present invention;

[0058] Figure 6 It is a schematic diagram of the simulation result of the control torque of the wheeled mobile robot in the embodiment of the present invention;

[0059] Figure 7 It is a schematic diagram of the simulation result of the adaptive parameter estimation in the embodiment of the present invention;

[0060] Figure 8 It is a schematic diagram of the simulation result of the time interval of the control signal event trigger in the embodiment of the present invention. Detailed implementation manners

[0061] The following describes in detail a method for event-triggered adaptive trajectory tracking control of a wheeled mobile robot provided by the present invention in combination with the accompanying drawings and specific embodiments. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; moreover, the accompanying drawings are only for more specifically describing the embodiments and are not intended to specifically limit the present invention.

[0062] It should be noted that in the specification, when referring to "an embodiment", "embodiment", "exemplary embodiment", "some embodiments", etc., it indicates that the described embodiment may include specific features, structures or characteristics, but not necessarily every embodiment includes such specific features, structures or characteristics. In addition, when combining embodiments to describe specific features, structures or characteristics, implementing such features, structures or characteristics in combination with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the relevant art.

[0063] Generally, terms can be understood at least in part from their use in context. For example, at least in part depending on the context, the term "one or more" used herein can be used to describe any feature, structure or characteristic in a singular sense, or can be used to describe a combination of features, structures or characteristics in a plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey a set of exclusive factors, but rather can alternatively, at least in part depending on the context, allow for the existence of other factors that may not be explicitly described.

[0064] It is understood that the meanings of "on", "above", and "over" in the present invention should be interpreted in the broadest manner, such that "on" not only means "directly on" something, but also includes the meaning of being "on" something with intervening features or layers therebetween, and "above" or "over" not only means "above" or "over" something, but may also include the meaning of being "above" or "over" something with no intervening features or layers therebetween.

[0065] In addition, spatial relative terms such as "under", "below", "lower", "above", "upper", etc. may be used herein for convenience of description to describe the relationship of one element or feature with another or other elements or features, as shown in the drawings. The spatial relative terms are intended to cover different orientations in the use or operation of the device in addition to the orientation depicted in the drawings. The device may be oriented in other ways, and the spatial relative descriptive words used herein may be similarly interpreted accordingly.

[0066] The following embodiments are used to illustrate the present invention, but cannot be used to limit the protection scope of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention all fall within the scope claimed by the present invention.

[0067] Please refer to Figure 1-8 , the present invention provides a method for event-triggered adaptive trajectory tracking control of a wheeled mobile robot, including the following steps:

[0068] Step 1: Establish the kinematic and dynamic models of the mobile robot.

[0069] The structure of the wheeled mobile robot is as Figure 1 shown. Its front wheels are auxiliary wheels, and two rear wheels are drive wheels with a drive wheel radius of r = 0.05 m. Assuming that the center of mass of the wheeled mobile robot coincides with the geometric center, an inertial coordinate system O r X r Y r and a body coordinate system O b X b Y b are used to describe the planar motion of the wheeled mobile robot. The mass and moment of inertia of the wheeled mobile robot are m = 3 kg and I = 2 kg·m 2 , respectively. The distance between the drive wheels and the geometric center is l = 0.15 m. Without considering slipping and skidding, the kinematic equation of the wheeled mobile robot is

[0070]

[0071] where q = [x, y, θ]T is the position and attitude of the wheeled mobile robot, ζ = [v, ω] T is the speed and angular velocity of the wheeled mobile robot, J(q) ∈ 3×2 is the speed conversion matrix, and the non-holonomic constraint of the wheeled mobile robot can be described as The dynamic equation of the wheeled mobile robot is

[0072]

[0073] where M(q) ∈ 3×3 is the inertia matrix, is the centripetal force and Coriolis force matrix, G(q) ∈ 3 is the gravity vector, B(q) ∈ 3×2 is the input conversion matrix, τ ∈ 2 is the control torque, d = [0.4sin(0.6t), 0.3sin(0.4t), 0.1sin(0.5t)] T is the external disturbance, A T (q) ∈ 3 is the non-holonomic constraint vector, λ is the Lagrange multiplier, and their specific expressions are respectively G(q) = 0 3 ,

[0074] The model uncertainty is considered as M(q) = M 0 (q) + M Δ (q), where M 0 (q) = 0.95M(q) and M Δ (q) = 0.05M(q) represent the nominal part and the uncertain part respectively. Differentiating Equation (1) with respect to time gives

[0075]

[0076] Substituting Equation (3) into Equation (2) and applying the relation J T (q)A T (q) = 0 2 yields

[0077]

[0078] where H = (J T (q)M 0 (q)J(q)) -1 J T (q)B(q), represents the lumped uncertainty term. Assume that the lumped uncertainty term δ is bounded, i.e., there exists an unknown constant B > 0 such that δ i ≤ B, i = 1, 2.

[0079] Step 2: Design a kinematic controller based on the kinematic model of the wheeled mobile robot.

[0080] First, design a kinematic controller to enable the position and attitude of the wheeled mobile robot to track the desired position and attitude. The desired trajectory of the wheeled mobile robot is given as x r = sin(t) m, y r = -cos(t) m, θ r = trad, v r = 1 m / s, ω r = 1 rad / s, satisfying the relationship:

[0081]

[0082] Define the position and attitude tracking errors of the wheeled mobile robot:

[0083]

[0084] Then the kinematic error equation of the wheeled mobile robot can be expressed as

[0085]

[0086] The kinematic controller of the wheeled mobile robot is designed as

[0087]

[0088] where h 1 = 10, h 2 = 10, h 3 = 10, v c and ω c are the virtual linear and angular velocities.

[0089] Considering the wheeled mobile robot system described by equations (1) and (2), under the action of the kinematic controller (8), the position and attitude tracking errors of the wheeled mobile robot can asymptotically converge to zero.

[0090] Step 3: Design a dynamic controller based on the dynamic model of the wheeled mobile robot.

[0091] Then, design a dynamic controller to enable the linear and angular velocities of the wheeled mobile robot to track the virtual linear and angular velocities. Define the linear and angular velocity tracking errors of the wheeled mobile robot:

[0092]

[0093] Then the dynamic error equation of the wheeled mobile robot can be expressed as

[0094]

[0095] The event-triggered fixed-time adaptive controller is designed as

[0096]

[0097]

[0098]

[0099] where α = 911, β = 1311, k 1 = 4, k 2 = 4, λ 1 = 0.1, λ 2 = 0.1, λ = [λ 1 , λ 2 T , ε = 0.1, E(t) = τ(t) - u(t) represents the control command measurement error, and represent two adjacent control command trigger times, represents the estimated value of B. For a given vector x ∈ n and scalar p ∈, the symbol sig p (·) is defined as sig p (x) = [sig p (x 1 ), sig p (x 2 ), …, sig p (x n )] T , where sig p (x i ) = |x i | p sgn(x i ), and the symbol tanh(·) is defined as tanh(x) = [tanh(x 1 ), tanh(x 2 ), …, tanh(x n )] T . In addition, the parameter adaptation law is selected as

[0100]

[0101] where η 1 = 1, η 2 = 1, η 3 ​= 1. The event-triggered controller (11) updates the control instruction only when the event-triggering condition (12) is satisfied, thereby reducing the information transmission between the wheeled mobile robot control system and the actuator, and saving more information transmission resources.

[0102] Considering the wheeled mobile robot system described by equations (1) and (2), under the action of the event-triggered fixed-time adaptive controller (11) and the parameter adaptive law (14), the position and attitude tracking errors of the wheeled mobile robot can asymptotically converge to zero and no Zeno phenomenon occurs. According to the above steps, referring to Figure 2 , a control block diagram of an event-triggered adaptive trajectory tracking control method for a wheeled mobile robot is given.

[0103] The simulation results of the designed event-triggered adaptive trajectory tracking control method for the wheeled mobile robot are as Figures 3 to 8 shown. The total simulation duration is set to 20 s, and the sampling time interval is 0.01 s.

[0104] From Figure 4 and 5 , it can be seen that the proposed event-triggered controller can ensure that the position, attitude, speed, and angular velocity tracking errors of the wheeled mobile robot converge to zero, with high control accuracy and fast convergence speed.

[0105] Figure 6 The schematic diagram of the simulation results of the control torque of the wheeled mobile robot is given. Under the action of the proposed event-triggered controller, the control torque curve shows a quantization characteristic, which is caused by the non-periodic sampling due to the introduction of the event-triggering mechanism.

[0106] Figure 7 The schematic diagram of the simulation results of the adaptive parameter estimation is given. The adaptive parameter changes smoothly with time and can finally converge to a constant value.

[0107] Figure 8 The schematic diagram of the simulation results of the event-triggering time interval of the control signal is given. Using the proposed event-triggered controller, within 20 s, the control torque τ 1 triggers 209 times, and the control torque τ 2 triggers 199 times. While using the time-triggered controller, within 20 s, the control torque τ 1 and τ 2 both trigger 2000 times. Under the action of the proposed event-triggered controller, the information transmission frequency between the wheeled mobile robot control system and the actuator is significantly reduced, avoiding the waste of information transmission resources. The designed controller is easy to implement, consumes less resources, has good tracking performance, and is suitable for tasks such as logistics transportation, power grid inspection, and disaster relief, with a wide application range.

[0108] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The words such as "comprising" or "including" used in the present invention mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words such as "connected" or "coupled" do not limit to physical or mechanical connections, and may also include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", and "right" are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0109] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An event-triggered adaptive trajectory tracking control method for a wheeled mobile robot, characterized in that: The following steps are involved: Step 1: Establish the kinematic and dynamic models of the mobile robot; Step 2: Design a kinematic controller based on the kinematic model of the wheeled mobile robot; Step 3: Design a dynamic controller based on the dynamic model of the wheeled mobile robot.

2. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 1, characterized in that: In step 1, the front wheels of the mobile robot are auxiliary wheels, the two rear wheels are driving wheels, and the radius of the driving wheel is r. Assuming that the center of mass of the wheeled mobile robot coincides with the geometric center, an inertial coordinate system O is established. r X r Y r and the body coordinate system O b X b Y b Describe the planar motion of a wheeled mobile robot. The mass and moment of inertia of the wheeled mobile robot are m and I respectively, and the distance between the driving wheel and the geometric center is l. Ignoring slip and sideslip, the kinematic equation of the wheeled mobile robot is Where q = [x, y, θ] T is the position and posture of the wheeled mobile robot, ζ=[v,ω] T is the speed and angular velocity of the wheeled mobile robot, J(q)∈ 3×2 is the velocity conversion matrix, and the nonholonomic constraints of the wheeled mobile robot can be described as 3. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 2, characterized in that: The dynamic equation of the wheeled mobile robot in step S1 is: Where M(q)∈ 3×3 is the inertia matrix, is the centripetal force and Coriolis force matrix, G(q)∈ 3 is the gravity vector, B(q)∈ 3×2 is the input transformation matrix, τ∈ 2 is the control torque, d∈ 3 is the external disturbance, A T (q)∈ 3 is the nonholonomic constraint vector and λ is the Lagrange multiplier.

4. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 1, characterized in that: In step 2, a kinematic controller is designed so that the position and posture of the wheeled mobile robot can track the desired position and posture. The desired trajectory of the wheeled mobile robot is given as:

5. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 4, characterized in that: The position and posture tracking errors of the wheeled mobile robot are defined in step 2 as follows:

6. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 5, characterized in that: The kinematic error equation of the wheeled mobile robot in step 2 is expressed as:

7. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 6, characterized in that: The kinematic controller of the wheeled mobile robot in step 2 is designed as follows: In the formula, h1>0, h2>0, h3>0, v c and ω c are the virtual speed and angular velocity.

8. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 1, characterized in that: The speed and angular velocity tracking errors of the wheeled mobile robot are defined in step 3 as: The dynamic error equation of the wheeled mobile robot can be expressed as: The event-triggered fixed-time adaptive controller is designed as: In the formula, 0<α<1, β>1, k1>0, k2>0, λ1>0, λ2>0, λ=[λ1,λ2] T , ε>0, E(t)=τ(t)-u(t) represents the control command measurement error, and Indicates the triggering time of two adjacent control instructions. Represents the estimated value of B, for a given vector x∈ n and scalar p∈, symbol sig p (·) is defined as sig p (x) = [sig p (x1),sig p (x2),…,sig p (x n )] T , where sig p (x i )=|x i p sgn(x i ), the symbol tanh(·) is defined as tanh(x)=[tanh(x1),tanh(x2),…,tanh(x n )] T 。 9. The event-triggered adaptive trajectory tracking control method for a wheeled mobile robot according to claim 8, characterized in that: The parameter adaptation law is selected as In the formula, η1>0, η2>0, η3>0.

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