A trajectory tracking method, device and mobile robot based on voltage control

Abstract

The present application relates to a trajectory tracking method, device and mobile robot based on voltage control. The method establishes a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and lateral slip; establishes a second dynamic model of the drive motor; obtains an overall dynamic model based on the first dynamic model and the second dynamic model; obtains an outer-loop control loop based on the kinematic model and the kinematic control module; realizes the posture tracking of the mobile robot based on the outer-loop control loop; obtains an inner-loop control loop with voltage as the control input of the overall dynamic model based on the dynamic control module and the overall dynamic model; uses a linear extended state observer based on the inner-loop control loop to estimate and compensate for the introduced lumped disturbance, and designs an anti-disturbance rejection controller to make the current speed of the mobile robot converge to the expected speed generated by the kinematic control module, so as to realize accurate trajectory tracking of the mobile robot and improve the motion control performance of the mobile robot.

Description

Technical Field

[0001] The present application relates to the technical field of mobile robots, and in particular to a trajectory tracking method, device and mobile robot based on voltage control. Background Art

[0002] Mobile robots with autonomous mobility, such as sweepers, mops, and service robots, are typical nonholonomic systems. Their motion control is a key and challenging area of ​​current research. Current research on mobile robot motion control schemes is largely based on the ideal constraint of "pure rolling without slipping." However, in actual operation, longitudinal or lateral wheel slippage (slipping) is common due to factors such as tire deformation, wet or icy roads, and rapid cornering. These conditions violate the nonholonomic constraints of the system, complicating the design of the mobile robot's motion control and potentially leading to loss of control.

[0003] During the implementation process, the inventors found that there are at least the following problems in traditional technologies: the control schemes all assume that the torque command is used as the input of the robot system. However, in practice, the robot is driven by a motor with a voltage input, and the impact of longitudinal and lateral slip disturbances on the motion control of the mobile robot is not comprehensively considered, which reduces the motion control performance of the mobile robot in high-speed tracking control. Summary of the Invention

[0004] Based on this, it is necessary to provide a trajectory tracking method, device and mobile robot based on voltage control to address the problem of reduced trajectory tracking control performance of a mobile robot caused by longitudinal and side slip disturbances.

[0005] To achieve the above object, an embodiment of the present invention provides a trajectory tracking method based on voltage control, comprising the following steps:

[0006] Establish the kinematic model and the first dynamic model of the mobile robot under unknown longitudinal and lateral sliding;

[0007] Establishing a second dynamic model of the mobile robot driving motor; obtaining an overall dynamic model based on the first dynamic model and the second dynamic model;

[0008] An outer control loop is obtained according to the kinematic model and a pre-established kinematic control module; and the position tracking of the mobile robot is realized based on the outer control loop;

[0009] According to the pre-established dynamic control module and overall dynamic model, an inner control loop with voltage as the input of the overall dynamic model is obtained; based on the inner control loop, a linear extended state observer is used to estimate and compensate for the introduced lumped disturbance, and an auto-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module, so as to achieve trajectory tracking of the mobile robot.

[0010] In one embodiment, the steps of estimating and compensating the introduced lumped disturbance based on the inner control loop and using a voltage control method include:

[0011] A linear extended state observer is designed to estimate and compensate for the lumped disturbance introduced into the overall dynamic model. The lumped disturbance includes any one or any combination of the following information: unknown longitudinal and lateral slip disturbance information of the mobile robot, modeling uncertainty, and unknown input disturbance information.

[0012] In one embodiment, the linear extended state observer is obtained by the following function:

[0013]

[0014] in, are the estimated values ​​of the state vectors x1, x2, and x3, respectively, x1=z, x3=d s , z is the actual speed of the mobile robot, is the system lumped disturbance, and ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、Ra 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, N is the mechanical gear reduction ratio; β1, β2, β3 are the first gain, second gain and third gain of the linear extended state observer respectively, and their values ​​are: ω o >0 is the observer bandwidth;

[0015] u a =[u ar u al ] T Indicates the control voltage of the right and left driving wheels of the mobile robot.

[0016] In one embodiment, the step of causing the current speed of the mobile robot to converge to the desired speed generated by the kinematic control module includes:

[0017] An active disturbance rejection controller is designed to control the current speed of the mobile robot so that the current speed of the mobile robot converges to the desired speed generated by the kinematic control module.

[0018] In one embodiment, the active disturbance rejection controller is obtained by the following function:

[0019]

[0020] in, are the estimated values ​​of the state vectors x1, x2, and x3, respectively, x1=z, x3=d s , z is the actual speed of the mobile robot, is the system lumped disturbance, and ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, N is the mechanical gear reduction ratio, z c is the auxiliary speed of the mobile robot, is the controller gain, ω c >0 is the controller bandwidth,

[0021] In one embodiment, the overall kinetic model is obtained by the following function:

[0022]

[0023] Among them, u a =[u ar u al ] T Indicates the control voltage of the right and left driving wheels of the mobile robot.

[0024]

[0025] ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ rare the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, and N is the mechanical gear reduction ratio.

[0026] In one embodiment, the pre-built kinematic control module includes an auxiliary kinematic controller designed by backstepping.

[0027] In one embodiment, the auxiliary kinematic controller is obtained by the following function:

[0028]

[0029] where v c 、ω c are the auxiliary linear velocity and auxiliary angular velocity of the designed mobile robot, v r 、ω r are the reference linear velocity and reference angular velocity of the mobile robot respectively, k1, k2, k3 are the control parameters of the auxiliary kinematic controller, and they are all positive numbers, e x is the longitudinal error of the mobile robot, e y is the lateral error of the mobile robot, e θ is the direction error of the mobile robot.

[0030] On the other hand, an embodiment of the present invention further provides a trajectory tracking device based on voltage control, comprising:

[0031] A first model building unit is used to build a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and side slip;

[0032] The second model building unit is used to build a second dynamic model of the driving motor of the mobile robot; and obtain an overall dynamic model based on the first dynamic model and the second dynamic model;

[0033] A posture tracking unit is used to obtain an outer control loop based on a kinematic model and a pre-established kinematic control module; and to implement posture tracking of the mobile robot based on the outer control loop;

[0034] The trajectory tracking unit is used to obtain an inner control loop with voltage as the input of the overall dynamic model based on the pre-established dynamic control module and overall dynamic model; based on the inner control loop, a linear extended state observer is used to estimate and compensate for the introduced lumped disturbance, and an auto-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module, so as to achieve trajectory tracking of the mobile robot.

[0035] On the other hand, an embodiment of the present invention further provides a mobile robot, comprising a mobile robot body and a controller arranged on the mobile robot body; the controller is used to execute any one of the above-mentioned trajectory tracking methods based on voltage control.

[0036] The above technical solution has the following advantages and beneficial effects:

[0037] In each embodiment of the above-mentioned voltage-controlled trajectory tracking method, a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and lateral slip are established; a second dynamic model of the driving motor of the mobile robot is established; an overall dynamic model is obtained based on the first dynamic model and the second dynamic model; an outer-loop control loop is obtained based on the kinematic model and a pre-established kinematic control module; based on the outer-loop control loop, the posture tracking of the mobile robot is realized; based on the pre-established dynamic control module and the overall dynamic model, an inner-loop control loop with voltage as the input of the overall dynamic model is obtained; based on the inner-loop control loop, a linear extended state observer is used to estimate and compensate for the introduced lumped disturbance, and an anti-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the expected speed generated by the kinematic control module to realize the trajectory tracking of the mobile robot, thereby overcoming the problem of reduced trajectory tracking control performance of the mobile robot caused by longitudinal slip and lateral slip disturbances, and improving the motion control performance of the mobile robot in high-speed tracking control. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of an application environment of a trajectory tracking method based on voltage control in one embodiment;

[0039] Figure 2 1 is a schematic diagram of a first flow chart of a trajectory tracking method based on voltage control in one embodiment;

[0040] Figure 3 1 is a second flow chart of a trajectory tracking method based on voltage control in one embodiment;

[0041] Figure 4 1 is a schematic diagram of a third flow chart of a trajectory tracking method based on voltage control in one embodiment;

[0042] Figure 51 is a schematic diagram of a control structure of a trajectory tracking method based on voltage control in one embodiment;

[0043] Figure 6 Schematic diagram of a trajectory tracking effect curve of a straight motion trajectory in one embodiment;

[0044] Figure 7 Schematic diagram of the tracking effect curve of each direction of the straight motion trajectory in one embodiment;

[0045] Figure 8 Schematic diagram of a posture tracking error curve of a straight motion trajectory in one embodiment;

[0046] Figure 9 Schematic diagram of the actual speed curve of the robot in a straight motion trajectory in one embodiment;

[0047] Figure 10 Schematic diagram of various disturbances and estimated value curves of a straight motion trajectory in one embodiment;

[0048] Figure 11 A schematic diagram of a control voltage input curve including a drive motor model for a straight motion trajectory in one embodiment;

[0049] Figure 12 A schematic diagram of a control torque input curve of a non-driven motor model for a straight motion trajectory in one embodiment;

[0050] Figure 13 Schematic diagram of a trajectory tracking effect curve of an arc motion trajectory in one embodiment;

[0051] Figure 14 Schematic diagram of the tracking effect curve of the arc motion trajectory in each direction in one embodiment;

[0052] Figure 15 Schematic diagram of a posture tracking error curve of a circular motion trajectory in one embodiment;

[0053] Figure 16 Schematic diagram of the actual speed curve of the robot with circular motion trajectory in one embodiment;

[0054] Figure 17 Schematic diagram of various disturbances of the arc motion trajectory and their estimated value curves in one embodiment;

[0055] Figure 18 A schematic diagram of a control voltage input curve including a drive motor model for an arc motion trajectory in one embodiment;

[0056] Figure 19 A schematic diagram of a control torque input curve of a non-driven motor model with a circular motion trajectory in one embodiment;

[0057] Figure 20 Schematic diagram of trajectory tracking characteristic curves in various directions of an in-situ rotation motion trajectory in one embodiment;

[0058] Figure 21 Schematic diagram of a posture tracking error curve of an in-situ rotation motion trajectory in one embodiment;

[0059] Figure 22 Schematic diagram of the inner ring speed tracking curve of the in-situ rotation motion trajectory in one embodiment;

[0060] Figure 23 Schematic diagram of various disturbances and estimated value curves of the in-situ rotation trajectory in one embodiment;

[0061] Figure 24 A schematic diagram of a control voltage input curve including a driving motor model for an in-situ rotation motion trajectory in one embodiment;

[0062] Figure 25 A schematic diagram of a control torque input curve of a non-driven motor model with an in-situ rotation motion trajectory in one embodiment;

[0063] Figure 26 FIG. 4 is a block diagram of a trajectory tracking device based on voltage control in one embodiment. DETAILED DESCRIPTION

[0064] To help those skilled in the art better understand the present invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. It is clear that the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0065] It should be noted that the terms "first," "second," and the like in the specification and claims of the present application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this manner are interchangeable where appropriate for the embodiments of the present application described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or apparatus.

[0066] In addition, the term "plurality" shall mean two or more.

[0067] The voltage-controlled trajectory tracking method provided in this application can be applied to Figure 1 The mobile robot includes a controller 104 and a mobile robot body 102. The controller 104 is connected to the mobile robot body 102 and can be used to establish a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal and lateral slip conditions; establish a second dynamic model of the mobile robot's drive motor; obtain an overall dynamic model based on the first dynamic model and the second dynamic model; obtain an outer control loop based on the kinematic model and a pre-established kinematic control module; achieve posture tracking of the mobile robot based on the outer control loop; obtain an inner control loop with voltage as input to the overall dynamic model based on the pre-established dynamic control module and the overall dynamic model; use a linear extended state observer based on the inner control loop to estimate and compensate for introduced lumped disturbances, and design an auto-disturbance rejection controller to converge the current velocity of the mobile robot to the desired velocity generated by the kinematic control module, thereby achieving trajectory tracking of the mobile robot.

[0068] In order to solve the problem of reduced trajectory tracking control performance of the mobile robot caused by longitudinal and side slip disturbances, in one embodiment, as Figure 2 As shown in FIG, a trajectory tracking method based on voltage control is provided. Figure 1 The controller 104 in FIG. 1 is used as an example to illustrate the invention, including:

[0069] Step S210 , establishing a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and lateral slip conditions.

[0070] The mobile robot may be, but is not limited to, a robot with self-propelled functions, such as a sweeping robot, a mopping robot, and a service robot. The first dynamics model refers to the first dynamics model that does not include a drive motor module.

[0071] For example, the mobile robot posture can be defined as (x, y) represents the position of the geometric center of the mobile robot in the global coordinate system, and θ represents the orientation angle of the mobile robot. In the presence of longitudinal and side slip disturbances, the kinematic model of the mobile robot can be expressed as (the first formula):

[0072]

[0073] where z = [vω] T , v and ω are the linear velocity and angular velocity of the mobile robot respectively; η=[η v η ω ] T , η v =r(ξ r +ξ l) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot; is the mismatched disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot; S(q) has the following form:

[0074]

[0075] Step S220 , establishing a second dynamic model of the driving motor of the mobile robot; and obtaining an overall dynamic model based on the first dynamic model and the second dynamic model.

[0076] The second dynamic model is the one that takes the drive motor model into account. Because unmodeled high-frequency disturbances also exist in the motor dynamics, the influence of motor dynamics must be considered in the control design to improve system control accuracy. This leads to the establishment of a second dynamic model for the mobile robot's drive motor. The overall dynamic model is derived from the first and second dynamic models.

[0077] Step S230: obtaining an outer control loop according to the kinematic model and a pre-established kinematic control module; and realizing posture tracking of the mobile robot based on the outer control loop.

[0078] The kinematic control module can be obtained according to system presets, and the controller can be based on a dual closed-loop control method, in which the kinematic control module is an outer loop control. The kinematic control module can be designed based on backstepping. The outer loop control loop formed tracks the position data of the mobile robot and drives the mobile robot so that its position error data converges to a first threshold. For example, the first threshold can be set to 0, so that the position tracking error of the mobile robot tends to zero.

[0079] In step S240, an inner control loop is obtained based on the pre-established dynamic control module and the overall dynamic model. Based on the inner control loop, a linear extended state observer is used to estimate and compensate for the introduced lumped disturbance, and an anti-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module, so as to achieve trajectory tracking of the mobile robot.

[0080] Among them, the dynamic control module can be obtained according to the system preset, and the controller can be based on a double closed-loop control method, in which the dynamic control module is an inner loop control.

[0081] Specifically, the controller can adopt voltage control instead of torque control based on the inner-loop control loop, use the linear extended state observer to estimate and compensate the lumped disturbance introduced into the overall dynamic model, and drive the current speed of the mobile robot to converge to the desired speed generated by the kinematic control module according to the compensation result, thereby realizing the inner-loop speed tracking of the mobile robot and further realizing the trajectory tracking of the mobile robot.

[0082] It should be noted that the lumped disturbance may include any one or any combination of the following information: unknown longitudinal slip and sideslip disturbance information of the mobile robot, modeling uncertainty and unknown input disturbance information.

[0083] In the above embodiment, the controller establishes a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and lateral slip; establishes a second dynamic model of the mobile robot's drive motor; obtains an overall dynamic model based on the first dynamic model and the second dynamic model; obtains an outer-loop control loop based on the kinematic model and a pre-established kinematic control module; realizes the posture tracking of the mobile robot based on the outer-loop control loop; obtains an inner-loop control loop with voltage as the control input of the overall dynamic model based on the pre-established dynamic control module and the overall dynamic model; uses a linear extended state observer based on the inner-loop control loop to estimate and compensate for the introduced lumped disturbance, and designs an anti-disturbance rejection controller to make the current speed of the mobile robot converge to the expected speed generated by the kinematic control module to realize the trajectory tracking of the mobile robot, thereby overcoming the problem of reduced trajectory tracking control performance of the mobile robot caused by longitudinal slip and lateral slip disturbances, and improving the motion control performance of the mobile robot in high-speed tracking control.

[0084] In one embodiment, the overall kinetic model is obtained by the following function:

[0085]

[0086] Among them, u a =[u ar u al ] T Indicates the control voltage of the right and left driving wheels of the mobile robot.

[0087]

[0088] ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, and N is the mechanical gear reduction ratio.

[0089] For example, in the ideal case of pure rolling without sliding, the dynamic model of the mobile robot can be described as (the second formula):

[0090] in is the positive definite symmetric inertia matrix of the system, m and J are the mass and moment of inertia of the mobile robot respectively; is the centrifugal force and Coriolis force matrix of the system. Since the center of mass of the mobile robot coincides with the geometric center, this item is an all-zero matrix; is the gravity vector of the system, which is a zero vector for a mobile robot moving in a plane; is the system input transformation matrix, θ is the direction angle of the mobile robot, and b is half of the distance between the two driving wheels; τ r , τ l is the input torque of the right and left driving wheels of the system; is the nonholonomic constraint matrix of the system, and is the system constraint term, and (x, y) is the position of the geometric center of the mobile robot in the global coordinate system.

[0091] Combining the first and second formulas, we can get the third formula:

[0092]

[0093] In the formula is the non-matching disturbance vector caused by the sideslip of the mobile robot, and μ is the sideslip speed of the mobile robot.

[0094] Considering the uncertainty of the dynamic model parameters and the unknown dynamic input interference, the third formula can be rewritten as (the fourth formula):

[0095] where ΔM s M s The amount of change, is an unknown bounded differentiable torque disturbance.

[0096] definition Then the fourth formula can be further expressed as (fifth formula):

[0097]

[0098] Since there are also unmodeled high-frequency disturbances in the motor dynamics, in order to improve the system control accuracy, the influence of motor dynamics must be considered in the control design. Assume that the mobile robot is driven by two identical brushed DC motors. The dynamic equations of the left and right wheel drive motors are (Formula 6):

[0099] Among them, L a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, N is the mechanical gear reduction ratio, τ=[τ r τ l ] T represents the input torque of the right and left driving wheels of the mobile robot, u a =[u ar u al ] T ,I a =[I ar I al ] T are the control voltage and armature current of the driving motor respectively. The subscripts l and r represent the left and right driving wheels of the mobile robot respectively. w is the angular velocity of the driving motor, and (Formula 7):

[0100]

[0101] Combining the fifth, sixth, and seventh formulas, we can obtain the eighth formula:

[0102]

[0103] In the formula

[0104] From the eighth formula we can get (the ninth formula):

[0105] In the formula

[0106] So far, the control task is to design the drive motor input voltage u for a mobile robot system with longitudinal and lateral slip disturbances, model uncertainty, and unknown external disturbances. a , which enables the mobile robot to accurately achieve trajectory tracking control in slipping conditions.

[0107] In one embodiment, the pre-built kinematic control module includes an auxiliary kinematic controller designed by backstepping.

[0108] In one embodiment, the auxiliary kinematic controller is obtained by the following function:

[0109]

[0110] where v c 、ω c are the auxiliary linear velocity and auxiliary angular velocity of the designed mobile robot, v r 、ω r are the reference linear velocity and reference angular velocity of the mobile robot respectively, k1, k2, k3 are the control parameters of the auxiliary kinematic controller, and they are all positive numbers, e x is the longitudinal error of the mobile robot, e y is the lateral error of the mobile robot, e θ is the direction error of the mobile robot.

[0111] For example, for the trajectory tracking control of a mobile robot considering motor dynamics under unknown longitudinal and lateral slip disturbances, modeling uncertainty and unknown input disturbances, a backstepping auto-disturbance rejection double closed-loop control strategy is adopted. The control structure is as follows: Figure 5 shown.

[0112] The outer loop is a kinematic controller. It uses the error between the mobile robot's reference and actual poses as input and uses backstepping to design an auxiliary kinematic controller. This controller generates auxiliary linear and angular velocities, ensuring that the pose error converges asymptotically to zero. The inner loop is a dynamic controller. The error between the auxiliary velocity and the actual velocity is used as input for an active disturbance rejection dynamics controller. The linear extended state observer (LESO) is used to estimate and compensate for the dynamic lumped disturbance in real time, ensuring that the actual motion velocity of the mobile robot converges asymptotically to the auxiliary motion velocity, achieving trajectory tracking control.

[0113] The design process of the pre-established kinematic control module is as follows: define the desired posture of the mobile robot as The following kinematic equation is satisfied (the tenth formula):

[0114] Where z r =[v r ω r ] T , v r is the reference linear velocity of the mobile robot, ω r is the reference angular velocity of the mobile robot body around its geometric center.

[0115] The tracking error of the mobile robot posture is defined as (Formula 11):

[0116] The differential equation of the posture tracking error can be obtained by derivation (Formula 12):

[0117] The backstepping method is used to design the assisted kinematic control law of the mobile robot, and the following Lyapunov function (Formula 13) is selected:

[0118] Where k2 is a positive constant. Taking the derivative with respect to V1 and substituting the twelfth formula into it, we can get the fourteenth formula:

[0119]

[0120] Design of assisted kinematic control input z for mobile robots c is (the fifteenth formula):

[0121]

[0122] Where v c 、ω c are the auxiliary linear velocity and angular velocity of the designed mobile robot respectively, k1, k2, k3 are the control parameters of the auxiliary kinematics control law and are all positive numbers.

[0123] Substituting the fifteenth formula into the fourteenth formula, we can get the sixteenth formula:

[0124]

[0125] It can be seen from this that in the auxiliary kinematic control input z c Under the action of q Tends to zero.

[0126] The control parameters k1, k2, and k3 in the auxiliary kinematic controller are tuned online using the pole placement method. Let ξ∈(0,1) be the system damping ratio, ω n>0 is the natural angular frequency of the system, and the desired pole of the mobile robot controlled system is selected as s1=-2ξω n , Its expected closed-loop characteristic polynomial can be expressed as (Formula 17):

[0127] Substituting the auxiliary kinematic control input formula (15) into the system error differential equation formula (12) and expanding it with the first-order Taylor formula in the neighborhood of the equilibrium point, we can obtain (formula (18)):

[0128]

[0129] System matrix A q The characteristic polynomial of is (Formula 19):

[0130]

[0131] Comparing the seventeenth formula with the nineteenth formula, we can get (the twentieth formula): k1+k3=4ξω n ,

[0132] From this we can get (Formula 21): k1=2ξω n , k3=2ξω n .

[0133] When v r →0, k2→∞, to avoid this situation, choose γ>0 is a positive constant, and the control parameter in the auxiliary kinematic control law is (Formula 22):

[0134] In one embodiment, Figure 3 As shown, the inner loop speed tracking processing steps include:

[0135] Step 310 : obtaining an inner control loop based on the pre-established dynamic control module and the overall dynamic model.

[0136] Step 320: Design a linear extended state observer to estimate and compensate for the lumped disturbance introduced into the overall dynamics model through the linear extended state observer, and design an auto-disturbance rejection controller to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module to achieve trajectory tracking of the mobile robot.

[0137] Specifically, the controller can accurately estimate the interference of longitudinal slip and sideslip, dynamic uncertainty, unknown external disturbances and drive motor dynamics on the mobile robot based on the linear extended state observer (LESO). The lumped disturbance introduced into the overall dynamic model can be observed and compensated by the linear extended state observer. Then, the inner-loop velocity tracking of the mobile robot can be performed through the anti-disturbance control controller, so that the current velocity of the mobile robot converges to the desired velocity generated by the kinematic control module, thereby realizing the trajectory tracking of the mobile robot.

[0138] For example, the design process of the linear extended state observer is as follows: define the state vector x1=z, x3=d s , then the ninth formula can be described as the state space form (the twenty-third formula):

[0139]

[0140] The linear extended state observer designed for the 23rd formula is (the 24th formula):

[0141]

[0142] in, are the estimated values ​​of the state vectors x1, x2, and x3 respectively, and β1, β2, and β3 are the gains of the extended state observer, which are: ω o >0 is the observer bandwidth. Define the observation error of the extended state observer By designing an appropriate observer bandwidth, the observation error of the extended state observer can be converged to a bounded range.

[0143] In one embodiment, Figure 4 As shown, the inner loop speed tracking processing steps also include:

[0144] Step 410 : Obtain an inner control loop based on the pre-established dynamic control module and the overall dynamic model.

[0145] Step 420 : Design a linear extended state observer to estimate and compensate for the lumped disturbance introduced into the overall dynamics model through the linear extended state observer.

[0146] Step 430 , designing an ADRC to track the current speed of the mobile robot through the ADRC so that the current speed of the mobile robot converges to the desired speed generated by the kinematic control module, thereby achieving trajectory tracking of the mobile robot.

[0147] Among them, the active disturbance rejection controller can be used to track the inner loop speed of the mobile robot and thus achieve trajectory tracking.

[0148] For example, the design process of the ADRC is as follows: Based on the dynamic model of the mobile robot, the ADRC is designed to assist the speed z c is the input and the actual speed z is the output. Based on the ADRC method, if the actual speed of the mobile robot converges to the auxiliary speed, the speed tracking error tends to zero. The speed tracking error is defined as (Formula 25): z =z c -z.

[0149] From the twenty-third formula we can get (the twenty-sixth formula):

[0150] Based on the 26th formula, the active disturbance rejection controller is designed as follows (the 27th formula):

[0151]

[0152] in, is the controller gain, ω c >0 is the controller bandwidth.

[0153] It should be understood that although Figures 2 to 4 The steps in the flowchart are shown in the order indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps and they can be executed in other orders. In addition, Figures 2 to 4 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The order of execution of these sub-steps or stages is not necessarily one by one, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0154] Mobile robots, such as sweeping robots, mopping robots, and service robots, are capable of autonomous locomotion. This embodiment uses a sweeping robot as an example to verify the effectiveness of the designed control algorithm. Simulation tests were conducted on the sweeping robot's trajectory tracking control under unknown longitudinal and lateral slip disturbances, unknown dynamic input disturbances, and model parameter uncertainty. Because mopping robots and service robots share certain similarities in their movement, this method is also applicable to mobile robots such as mopping robots and service robots.

[0155] Set the physical parameters and related parameters of the drive motor as follows:

[0156] m=2.7kg,J=0.033kg·m 2 ,r=0.034m,b=0.11m,

[0157] La =0.02H,R a =13.5Ω,k b =0.0239V / rad·s -1 ,

[0158] k t =0.0239(N·m) / A,N=54.5

[0159] The initial value of the reference trajectory of the sweeping robot is set to q r (0) = [0 0 0] T , the initial pose is set to q(0) = [0 0 0] T , the parameters of the kinematic control module are set to γ=50、ξ=0.707, and the parameters of the linear extended state observer are set to ω o =100, the parameters of the active disturbance rejection control module are set to ω c =20.

[0160] In order to further study the robustness of the proposed control module, it is assumed that the unknown dynamic input disturbance of the sweeping robot obeys the normal distribution function:

[0161] The uncertainty of the system is set as ΔM s =0.15M s In order to test the control effect of the designed control module on disturbances with different frequencies and amplitudes, this experiment gives longitudinal slip and side slip disturbances in the form of decaying sine, where the longitudinal slip angular velocity disturbances of the left and right driving wheels are:

[0162]

[0163] Side slip linear velocity disturbance: where t s is the starting time of the disturbance.

[0164] To verify the impact of the drive motor model on the control performance of the sweeping robot, the designed algorithm was simulated and compared with the backstepping active disturbance rejection control algorithm (NoActuator BCADRC) that does not consider the drive motor model. At the same time, to verify the control performance of the designed control algorithm, it was compared with the traditional double-closed-loop PID algorithm (DCLPID). The parameters of the DCLPID outer loop controller are set as:

[0165] k px =1000,k ix =0,k dx =4,k py =1000,k iy =0,k dy =5,kpθ =1000,k iθ =0,k dθ =4,

[0166] The inner loop controller parameters are:

[0167] k p =diag([64,64]),k i =diag([1,1]),k d =diag([16,16]).

[0168] The dynamic controller parameters of the BCADRC algorithm without considering the drive motor model are selected as: c =8,ω o =40, The kinematic controller parameters are the same as those of the proposed BCADRC kinematic controller.

[0169] In actual operating conditions, the trajectory of a sweeping robot can be divided into three categories: straight line, circular arc, and rotation. The following comparative analysis shows the control effects of different controllers under these three operating conditions.

[0170] Straight motion trajectory: According to the actual working conditions, the straight motion of the sweeping robot can be divided into two situations: no obstacles and obstacles. When there are no obstacles, the sweeping robot moves at a speed of v r =0.28m / s constant speed operation, at this time ω r = 0 rad / s. After detecting an obstacle, the linear velocity is reduced by half every second. Once the linear velocity decreases to within 0.02 m / s, the robot vacuum is considered to have stopped. Calculations show that after detecting an obstacle, the robot vacuum stops within 4 seconds, with a total displacement of 0.525 m during the deceleration process.

[0171] The simulation settings are as follows: simulation time 30s, sampling frequency 100Hz, the sweeping robot is in 0~20s with v r = 0.28m / s constant speed operation, of which longitudinal slip occurs from 5 to 8 seconds, lateral slip occurs from 10 to 13 seconds, and lumped disturbance is added from 15 to 18 seconds, that is, longitudinal slip and lateral slip occur simultaneously and modeling uncertainty and unknown input disturbance are considered. At 20 seconds, the sweeping robot detects an obstacle and its speed decreases. Lumped disturbance is added during the speed decrease process (21 to 23 seconds). The simulation results are shown as follows Figures 6-12 shown.

[0172] Specifically, Figure 6The figure shows the trajectory tracking task effect of the sweeping robot under lumped disturbances under the action of the auxiliary kinematic controller, linear extended state observer and active disturbance rejection controller. It can be seen that under longitudinal slip, side slip and lumped disturbances, the sweeping robot can still stably track the straight line reference trajectory, and the active disturbance rejection controller has better tracking effect and smaller tracking error than the other two control modules. Figure 7 and Figure 8 Figures 2 and 3 show the tracking performance and pose errors of the sweeping robot in various directions. Both the DCLPID and BCADRC algorithms, which do not consider the drive motor model, have large initial errors during robot startup. During constant speed operation, the DCLPID algorithm exhibits steady-state errors in the x-direction. Considering the drive motor model improves system control accuracy under longitudinal slip, side slip, and lumped disturbances. Compared to DCLPID control, the designed BCADRC algorithm achieves smaller pose errors and better performance. After the disturbance disappears, the designed BCADRC algorithm quickly adjusts to allow the robot to converge to the desired trajectory. Figure 9 The actual speed of the sweeping robot is shown in the figure. The BCADRC algorithm considering the drive motor model has smaller speed fluctuation and is more stable under disturbance. Figure 10 This is the observation effect of the linear extended state observer on the lumped disturbance. Analysis shows that the linear extended state observer has a good observation effect on the lumped disturbances of different frequencies and amplitudes, with small convergence error and high observation accuracy. Figure 11 In order to control the voltage change curve over time, when there is a disturbance, the control module makes real-time adjustments to suppress the impact of the disturbance on the system. Figure 12 The control torque change designed by the BCADRC algorithm does not consider the drive motor model. The control torque is adjusted in real time to compensate for the interference to achieve accurate trajectory tracking control.

[0173] Arc motion trajectory: Assume that the reference trajectory of the sweeping robot is a circular trajectory, and the reference speed is set to v r =0.28m / s,ω r =1rad / s, the robot's initial speed is set to v=0m / s, ω=0rad / s, and the other parameters are the same as the straight motion trajectory. When t=5~8s, the load of the sweeping robot changes slowly, and the change ΔM s =0.15M s , the robot experienced longitudinal slip at 10-13s, side slip at 15-18s, and lumped disturbance at 20-23s. The simulation results are as follows Figures 13-19 shown.

[0174] Depend on Figures 13-15It can be seen that under lumped disturbances, the robot vacuum can accurately track the reference trajectory using all three controllers. However, the DCLPID controller exhibits a certain steady-state error and requires a long period of adjustment during the startup phase before tracking the desired trajectory. For active disturbance rejection control, the BCADRC algorithm, which considers the drive motor model, can improve system control performance and reduce posture errors. Figure 16 The actual speed and angular velocity changes of the sweeping robot under three control algorithms are shown. The active disturbance rejection control considering the drive motor model quickly overcomes the disturbance interference with small overshoot and oscillation, making the linear velocity and angular velocity quickly converge to the auxiliary linear velocity and angular velocity. The control performance is much better than the DCLPID and BCADRC algorithms that do not consider the drive motor model. Figure 17 The linear extended state observer estimates the lumped disturbance with a small error, which can realize real-time and accurate estimation of the lumped disturbance. Figure 18 The curve of control voltage changing with time is given. Figure 19 The control torque change designed for the BCADRC algorithm does not consider the drive motor model. Trajectory tracking control is achieved under slip conditions through real-time adjustment of the control torque.

[0175] Rotation trajectory: In actual working conditions, the robot vacuum cleaner may rotate in place. A simulation is conducted to verify this situation. The reference speed of the robot vacuum cleaner in the simulation is set to v r =0m / s,ω r =1.22rad / s, and the rest of the parameters refer to the above embodiment. At t=5s, the load of the sweeping robot changes slowly, that is, ΔM s =0.15M s , the robot experienced longitudinal slip at 10-13s, side slip at 15-18s, and lumped disturbance at 20-23s. The simulation results are as follows Figures 20-25 shown.

[0176] Depend on Figure 20 and Figure 21 It can be seen that under lumped disturbances, DCLPID will have a large posture error. For active disturbance rejection control, considering the drive motor model can improve the control accuracy of the system. Figure 22 The figure shows the actual speed changes of the sweeping robot under the three control algorithms. It can be seen that the ADRC has small overshoot and oscillation. Figure 23 It is shown that the linear extended state observer can estimate the lumped disturbance accurately in real time. Figure 24 To drive the motor input voltage change curve, since the robot rotates in place, the input voltages of the left and right wheels are equal in magnitude and opposite in direction. When there is a disturbance, the designed controller adjusts the control voltage to suppress the influence of the disturbance on motion control. Figure 25The control torque change designed for the BCADRC algorithm does not consider the drive model. As the disturbance occurs, the control torque changes accordingly to suppress the influence of the disturbance.

[0177] In the above-mentioned embodiment, the robot vacuum's motion is affected by unknown longitudinal and lateral slip disturbances, model uncertainty, unknown input disturbances, and the dynamic characteristics of the drive motor. An auxiliary kinematic controller and an active disturbance rejection controller are designed based on a dual closed-loop control strategy. A linear extended state observer is used to estimate and compensate for disturbances in real time, enabling precise trajectory tracking control. Simulations demonstrate that incorporating the drive motor model into the controller design improves the robot vacuum's motion control performance. Active disturbance rejection control allows for real-time disturbance estimation and compensation, minimizes overshoot and oscillation, and exhibits enhanced robustness.

[0178] In one embodiment, Figure 26 As shown, a trajectory tracking device based on voltage control is also provided, comprising:

[0179] The first model building unit 210 is used to build a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and lateral slip conditions.

[0180] The second model building unit 220 is used to build a second dynamic model of the driving motor of the mobile robot; and obtain an overall dynamic model according to the first dynamic model and the second dynamic model.

[0181] The posture tracking unit 230 is used to obtain an outer control loop according to the kinematic model and a pre-established kinematic control module; and realize the posture tracking of the mobile robot based on the outer control loop.

[0182] The trajectory tracking unit 240 obtains an inner control loop with voltage as the input of the overall dynamic model based on the pre-established dynamic control module and the overall dynamic model; based on the inner control loop, a linear extended state observer is used to estimate and compensate for the introduced lumped disturbance, and an anti-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module, so as to realize the trajectory tracking of the mobile robot.

[0183] The specific definition of the voltage-controlled trajectory tracking device can be found in the definition of the voltage-controlled trajectory tracking method above, and will not be repeated here. Each module in the above-mentioned voltage-controlled trajectory tracking device can be implemented in whole or in part through software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the controller of the mobile robot in hardware form, or can be stored in the memory of the mobile robot in software form, so that the controller can call and execute the corresponding operations of each of the above modules.

[0184] In one embodiment, a mobile robot is further provided, comprising a mobile robot body and a controller arranged on the mobile robot; the controller is used to execute any one of the above-mentioned trajectory tracking methods based on voltage control.

[0185] The controller is used to perform the following steps of the trajectory tracking method based on voltage control:

[0186] Establish a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and sideslip; establish a second dynamic model of the mobile robot's drive motor; obtain the overall dynamic model based on the first dynamic model and the second dynamic model; obtain an outer control loop based on the kinematic model and a pre-established kinematic control module; based on the outer control loop, realize the posture tracking of the mobile robot; based on the pre-established dynamic control module and the overall dynamic model, obtain an inner control loop with voltage as the control input of the overall dynamic model; based on the inner control loop, use a linear extended state observer to estimate and compensate for the introduced lumped disturbance, and design an anti-disturbance rejection controller to make the current speed of the mobile robot converge to the expected speed generated by the kinematic control module to realize the trajectory tracking of the mobile robot.

[0187] In the above embodiment, a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and lateral slip are established; a second dynamic model of the mobile robot drive motor is established; an overall dynamic model is obtained based on the first dynamic model and the second dynamic model; an outer loop control loop is obtained based on the kinematic model and a pre-established kinematic control module; the posture tracking of the mobile robot is realized based on the outer loop control loop; an inner loop control loop with voltage as the input of the overall dynamic model is obtained based on the pre-established dynamic control module and the overall dynamic model; a linear extended state observer is used based on the inner loop control loop to estimate and compensate for the introduced lumped disturbance, and an anti-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the expected speed generated by the kinematic control module to realize the trajectory tracking of the mobile robot, thereby overcoming the problem of reduced trajectory tracking control performance of the mobile robot caused by longitudinal slip and lateral slip disturbances, and improving the motion control performance of the mobile robot in high-speed tracking control.

[0188] In one embodiment, a computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above-mentioned voltage-controlled trajectory tracking methods are implemented.

[0189] In one example, the computer program, when executed by a processor, implements the following steps:

[0190] Establish a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and sideslip; establish a second dynamic model of the mobile robot drive motor; obtain the overall dynamic model based on the first dynamic model and the second dynamic model; obtain an outer-loop control loop based on the kinematic model, the overall dynamic model, the pre-established kinematic control module and the pre-established dynamic control module; based on the outer-loop control loop, realize the posture tracking of the mobile robot; based on the pre-established dynamic control module and the overall dynamic model, obtain an inner-loop control loop with voltage as the input of the overall dynamic model; based on the inner-loop control loop, use a linear extended state observer to estimate and compensate for the introduced lumped disturbance, and design an anti-disturbance rejection controller to make the current speed of the mobile robot converge to the expected speed generated by the kinematic control module to realize the trajectory tracking of the mobile robot.

[0191] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by hardware related to computer program instructions. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0192] The various technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0193] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A trajectory tracking method based on voltage control, characterized in that: The steps include: Establish the kinematic model and the first dynamic model of the mobile robot under unknown longitudinal and lateral sliding; Establishing a second dynamic model of the mobile robot drive motor; obtaining an overall dynamic model based on the first dynamic model and the second dynamic model; Obtaining an outer control loop according to the kinematic model and a pre-established kinematic control module; and achieving posture tracking of the mobile robot based on the outer control loop; Based on the pre-established dynamic control module and the overall dynamic model, an inner control loop is obtained, which uses voltage as a control input of the overall dynamic model; a linear extended state observer is used based on the inner control loop to estimate and compensate for the introduced lumped disturbance, and an auto-disturbance rejection controller is designed to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module, so as to achieve trajectory tracking of the mobile robot; The step of estimating and compensating the introduced lumped disturbance based on the inner control loop and using a voltage control method includes: A linear extended state observer is designed to estimate and compensate for a lumped disturbance introduced into the overall dynamic model, wherein the lumped disturbance includes any one or any combination of the following information: unknown longitudinal and lateral slip disturbance information of the mobile robot, modeling uncertainty, and unknown input disturbance information; The linear extended state observer is obtained by the following function: in, are the estimated values ​​of the state vectors x1, x2, and x3, respectively, x1 = z, x3=d s , z is the actual speed of the mobile robot, is the system lumped disturbance, and ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, and N is the mechanical gear reduction ratio; β1, β2, and β3 are the first gain, second gain, and third gain of the linear extended state observer respectively, and their values ​​are: ω o >0 is the observer bandwidth; u a =[u ar u al ] T Indicates the control voltage of the right and left driving wheels of the mobile robot; The step of causing the current speed of the mobile robot to converge to the desired speed generated by the kinematic control module comprises: Designing an active disturbance rejection controller to control the current speed of the mobile robot by the active disturbance rejection controller so that the current speed of the mobile robot converges to the desired speed generated by the kinematic control module; The active disturbance rejection controller is obtained by the following function: in, are the estimated values ​​of the state vectors x1, x2, and x3, respectively, x1 = z, x3=d s , z is the actual speed of the mobile robot, is the system lumped disturbance, and ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, and N is the mechanical gear reduction ratio; c is the auxiliary speed of the mobile robot, is the controller gain, ω c >0 is the controller bandwidth; The overall kinetic model is obtained by the following function: Among them, u a =[u ar u al ] T Indicates the control voltage of the right and left driving wheels of the mobile robot. ΔM s M s The change in τ d is an unknown bounded differentiable torque disturbance, is the non-matching disturbance vector caused by the sideslip of the mobile robot, μ is the sideslip speed of the mobile robot, θ is the direction angle of the mobile robot, η=[η v η ω ] T , η v =r(ξ r +ξ l ) / 2 is the longitudinal sliding speed, η ω =r(ξ r -ξ l ) / (2b) is the yaw rate disturbance caused by longitudinal slip, r is the radius of the driving wheel of the mobile robot, 2b is the distance between the two driving wheels, ξ l ,ξ r are the interference angular velocities caused by the longitudinal slip of the left and right driving wheels of the mobile robot, m and J are the mass and moment of inertia of the mobile robot, respectively. a 、R a 、k t 、k b are the armature inductance, armature resistance, torque constant and back electromotive force constant of the drive motor respectively, and N is the mechanical gear reduction ratio.

2. The trajectory tracking method based on voltage control according to claim 1, characterized in that: The pre-established kinematic control module includes an auxiliary kinematic controller designed by backstepping method.

3. The trajectory tracking method based on voltage control according to claim 2, characterized in that: The auxiliary kinematic controller is obtained by the following function: where v c 、ω c are the auxiliary linear velocity and auxiliary angular velocity of the designed mobile robot, v r 、ω r are the reference linear velocity and reference angular velocity of the mobile robot respectively, k1, k2, k3 are the control parameters of the auxiliary kinematic controller, and they are all positive numbers, e x is the longitudinal error of the mobile robot, e y is the lateral error of the mobile robot, e θ is the direction error of the mobile robot.

4. A trajectory tracking device based on voltage control, used to implement the trajectory tracking method based on voltage control according to any one of claims 1 to 3, characterized in that: include: A first model building unit is used to build a kinematic model and a first dynamic model of the mobile robot under unknown longitudinal slip and side slip; A second model building unit is configured to build a second dynamic model of the mobile robot drive motor; and obtain an overall dynamic model based on the first dynamic model and the second dynamic model; A posture tracking unit is configured to obtain an outer control loop based on the kinematic model and a pre-established kinematic control module; and implement posture tracking of the mobile robot based on the outer control loop; The trajectory tracking unit is used to obtain an inner-loop control loop with voltage as the control input of the overall dynamic model based on the pre-established dynamic control module and the overall dynamic model; use a linear extended state observer based on the inner-loop control loop to estimate and compensate for the introduced lumped disturbance, and design an auto-disturbance rejection controller to make the current speed of the mobile robot converge to the desired speed generated by the kinematic control module, so as to achieve trajectory tracking of the mobile robot.

5. A mobile robot, characterized in that: It comprises a mobile robot body and a controller arranged on the mobile robot body; the controller is used to execute the trajectory tracking method based on voltage control as described in any one of claims 1 to 3.

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