A preset time control method and system for wheeled mobile robots under multiple disturbances

Abstract

The application discloses a preset time control method and system for a wheeled mobile robot under multiple disturbances, and comprises the following steps: establishing a nonlinear motion model of a wheeled mobile robot under matched and unmatched disturbances; designing a preset time adjustment function to regulate and control the dynamic evolution process of system errors; designing a kinematic disturbance observer and a dynamic disturbance observer to online estimate the matched and unmatched disturbances; and constructing a kinematic controller, a filter and a dynamic controller according to the disturbance estimation information, so as to realize robust preset time tracking control of the wheeled mobile robot on a reference trajectory. The method provided by the application can guarantee the convergence of system errors within a preset time without relying on the ideal no-slip assumption, has the advantages of adjustable convergence time, continuous and smooth control input, strong anti-interference ability and high engineering realizability, and improves the anti-interference performance of the robot in a complex dynamic environment and the reliability of a time-sensitive task.

Description

Technical Field

[0001] This invention belongs to the field of wheeled mobile robot control technology, and particularly relates to a preset time control method and system for wheeled mobile robots under multiple disturbances. Background Technology

[0002] In recent years, with the rapid development of autonomous mobile robots and intelligent transportation systems, wheeled mobile robots have been widely used in industrial logistics, intelligent manufacturing, planetary surface exploration, and agricultural automation. When wheeled mobile robots perform autonomous operations in complex environments, their motion control not only requires high-precision trajectory tracking capabilities but also must ensure that tracking errors converge within strict time constraints to meet the needs of task scheduling and collaborative control. In typical application scenarios such as multi-robot formation, collaborative handling, interactive logistics systems with time windows, high-dynamic obstacle avoidance, and task segment switching, whether the control system can enable the robot to reach the target trajectory within a predetermined time directly affects the rhythm of multi-robot collaboration, the connection of the task execution chain, and the timing guarantee of key actions. If the wheeled mobile robot fails to reach the expected state at the designated time, it may lead to loss of coordination, path conflicts, resource scheduling delays, or missed optimal operation time, thereby affecting system stability and operational safety.

[0003] However, the kinematics and dynamics of wheeled mobile robots are characterized by nonholonomic constraints, strong nonlinearity, and susceptibility to multi-source disturbances. Complex operating environments often involve variations in ground friction coefficients, lateral centrifugal forces, and random external force disturbances, posing significant challenges to trajectory tracking control. Particularly in real-world scenarios, the pure rolling assumption commonly used in traditional research often proves untenable. Wheel slippage is unavoidable under conditions of high-speed motion, complex terrain, and abrupt changes, leading to significant modeling errors and a decline in tracking performance. Furthermore, while existing control methods can improve robustness to some extent, most only achieve asymptotic stability, with trajectory errors only approaching zero in infinite time, failing to meet the rigid time requirements of time-sensitive tasks. Finite-time control can achieve convergence within a finite time, but its convergence time depends on initial conditions, making it difficult to obtain a predictable convergence moment during the task planning phase. Fixed-time control, while making the convergence time independent of the initial state, has its upper convergence bound influenced by multiple coupled control parameters, making it difficult to establish a direct correspondence between engineering parameters and convergence time, thus limiting its practical adjustability and usability. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a method and system for preset time control of a wheeled mobile robot under multiple disturbances.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a preset time control method for a wheeled mobile robot under multiple disturbances.

[0007] In one or more embodiments, a method for preset time control of a wheeled mobile robot under multiple perturbations is provided, including:

[0008] Step 1: Considering the effects of multiple sources of interference such as roller skating and random external force disturbances, establish a nonlinear motion mathematical model of the wheeled mobile robot under matched and unmatched interference.

[0009] Step 2: Design a preset time adjustment function To regulate the dynamic evolution of system errors;

[0010] Step 3: Based on the established motion model of the wheeled mobile robot, integrate the designed preset time adjustment function. Kinematic and dynamic disturbance observers were designed to detect mismatched disturbances. and matching interference Online estimation;

[0011] Step 4: Based on interference estimation information and Combined with preset time adjustment function Constructing a kinematic controller ,filter and dynamic controller This enables robust, preset-time tracking control of a wheeled mobile robot for a reference trajectory.

[0012] Furthermore, the nonlinear motion mathematical model of the wheeled mobile robot subjected to matching and mismatch disturbances described in step one is as follows:

[0013]

[0014] In the formula, The position of the robot's center of gravity. Let be the angular velocities of the robot's right and left drive wheels. For the control torque of the robot's right and left wheels, Let be the Jacobian transformation matrix. Here is the robot's mass inertia matrix. For the inertial coupling matrix, and These are the mismatch and match perturbation terms, respectively; for positive constants... and ,exist and .

[0015] Furthermore, the preset time adjustment function mentioned in step two... Designed as follows:

[0016]

[0017] In the formula, To preset the convergence time, It is a constant.

[0018] Furthermore, the kinematic perturbation observer and the dynamic perturbation observer mentioned in step three are designed as follows:

[0019]

[0020] In the formula, , and These are the estimated values ​​for mismatched interference and matched interference, respectively. and These are the observer states, This is the observer gain.

[0021] Furthermore, the kinematic controller in step four ,filter and dynamic controller Designed as follows:

[0022]

[0023] In the formula, For position tracking error, For speed tracking error, For reference trajectory, For the derivative of the reference trajectory, and Design parameters for the filter. For filter control input, To control the gain.

[0024] A second aspect of the present invention provides a preset time control system for a wheeled mobile robot under multiple disturbances, the system comprising:

[0025] The model building module is used to analyze the effects of multi-source disturbances such as roller skating and random external force disturbances, and to establish nonlinear motion mathematical models of wheeled mobile robots subjected to matched and unmatched disturbances.

[0026] The preset time adjustment module is used to design a preset time function to regulate the dynamic evolution of system errors;

[0027] The interference estimation module is used to design an interference observer for online estimation of mismatched and matched interference.

[0028] The tracking control module is used to construct kinematic controllers, filters, and dynamic controllers to achieve robust preset time tracking control of the wheeled mobile robot on the reference trajectory.

[0029] A third aspect of the present invention provides a computer-readable storage medium.

[0030] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the pre-set time control method for a wheeled mobile robot under multiple disturbances as described above.

[0031] A fourth aspect of the present invention provides a computer device.

[0032] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the preset time control method for a wheeled mobile robot under multiple disturbances as described above.

[0033] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0034] First, the present invention can make real-time and accurate estimation and feedforward compensation for matched and unmatched disturbances caused by multiple sources of interference such as wheel slip and random external force disturbances. It breaks the dependence on the ideal physical conditions of "pure rolling and no slip" in traditional control and significantly improves the anti-interference performance and motion robustness of wheeled mobile robots in complex and dynamic environments.

[0035] Secondly, the preset time control method proposed in this invention enables the tracking and observation errors to converge within a desired preset time. Moreover, this convergence time has the advantages of being independent of the initial state of the system and having intuitively adjustable parameters. It effectively solves the problems of unpredictable convergence time or difficult parameter adjustment in traditional asymptotic control, finite time control and fixed time control, and significantly improves the controllability and reliability of wheeled mobile robots in time-sensitive tasks.

[0036] Third, this invention uses a smooth preset time adjustment function to replace the traditional discontinuous control strategy that relies on the sign function. While ensuring the preset convergence performance, it avoids the problems of control singularity, chattering and actuator input saturation, which significantly improves the safety, stability and feasibility of the control algorithm in actual engineering systems. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a flowchart of the preset time control method for a wheeled robot provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the preset time control principle of the wheeled robot provided in the embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of wheeled robot trajectory tracking under different expected convergence times provided in the embodiments of the present invention;

[0041] Figure 4 This is a graph showing the tracking error curves of a wheeled robot under different expected convergence times, provided by an embodiment of the present invention.

[0042] Figure 5 This is a graph showing the kinematic perturbation estimation error of a wheeled robot under different expected convergence times, provided by an embodiment of the present invention.

[0043] Figure 6 This is a graph showing the estimation error of the dynamic perturbation of a wheeled robot under different expected convergence times, provided by an embodiment of the present invention.

[0044] Figure 7 This is a graph showing the control input curves of a wheeled robot under different expected convergence times, provided by an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] To address the problems existing in the prior art, the present invention provides a method and system for preset time control of a wheeled mobile robot under multiple disturbances. The present invention will be described in detail below with reference to the accompanying drawings.

[0047] I. Explanatory and Illustrative Embodiments. To enable those skilled in the art to fully understand how the present invention is specifically implemented, this section provides an explanatory and illustrative description of the embodiments described in the claims.

[0048] like Figure 1 As shown, the preset time control method for a wheeled mobile robot under multiple disturbances provided in this embodiment of the invention includes the following steps:

[0049] S101, Construct a nonlinear motion mathematical model for a wheeled mobile robot affected by matching and mismatch disturbances;

[0050] S102, Design a preset time adjustment function to regulate the dynamic evolution of system error;

[0051] S103, Design a preset time-interference observer to estimate matched and mismatched interference online;

[0052] S104, Design a preset time controller to achieve robust preset time tracking control of wheeled robots.

[0053] Figure 2 This is a schematic diagram of the preset time trajectory tracking control principle of a wheeled mobile robot under multiple disturbances provided in an embodiment of the present invention.

[0054] As a preferred embodiment, combined with Figure 2 The preset time control method for a wheeled mobile robot under multiple disturbances provided in this embodiment of the invention specifically includes the following steps:

[0055] (1) Considering the effects of multiple sources of interference such as roller skating and random external force disturbances, establish a nonlinear motion mathematical model of a wheeled mobile robot subjected to matched and unmatched interference;

[0056] (2) Design a preset time adjustment function To regulate the dynamic evolution of system errors;

[0057] (3) Based on the established motion model of the wheeled mobile robot, the pre-designed time adjustment function is integrated. Kinematic and dynamic disturbance observers were designed to detect mismatched disturbances. and matching interference Online estimation;

[0058] (4) Based on interference estimation information and Combined with preset time adjustment function Constructing a kinematic controller ,filter and dynamic controller This enables robust, preset-time tracking control of a wheeled mobile robot for a reference trajectory.

[0059] In step (1), considering the effects of multiple sources of disturbance such as wheel slip and random external force disturbance, the following nonlinear motion mathematical model of the wheeled mobile robot under matched and unmatched disturbances is established:

[0060] (1)

[0061] In the formula, The position of the robot's center of gravity. Let be the angular velocities of the robot's right and left drive wheels. For the control torque of the robot's right and left wheels, Let be the Jacobian transformation matrix. Here is the robot's mass inertia matrix. For the inertial coupling matrix, and These are the mismatch and match perturbation terms, respectively; for positive constants... and ,exist and .

[0062] In step (2), a preset time adjustment function is used. Designed as follows:

[0063] (2)

[0064] In the formula, To preset the convergence time, It is a constant.

[0065] In step (3), the kinematic disturbance observer and the dynamic disturbance observer are designed as follows:

[0066] (3)

[0067] In the formula, , and These are the estimated values ​​for mismatched interference and matched interference, respectively. and These are the observer states, This is the observer gain.

[0068] In step (3), a kinematic controller is constructed. ,filter and dynamic controller To achieve robust preset time tracking control for wheeled mobile robots, the following are included:

[0069] To ensure that the position surface tracking error converges within a preset time, the kinematic controller... Designed as follows:

[0070] (4)

[0071] In the formula, For position tracking error, For reference trajectory, For the derivative of the reference trajectory, and To control the gain;

[0072] To avoid the computational complexity caused by backstepping control design, a first-order preset time filter is introduced for the kinematic controller. Processing:

[0073] (5)

[0074] In the formula, and Design parameters for the filter; This is the input for filter control;

[0075] To ensure that the velocity surface tracking error converges within a preset time, the dynamic controller... Designed as follows:

[0076] (6)

[0077] In the formula, For speed tracking error, and To control the gain.

[0078] The preset time control system for a wheeled mobile robot under multiple disturbances provided in this embodiment of the invention includes:

[0079] The model building module is used to analyze the effects of multi-source disturbances such as roller skating and random external force disturbances, and to establish nonlinear motion mathematical models of wheeled mobile robots subjected to matched and unmatched disturbances.

[0080] The preset time adjustment module is used to design a preset time function to regulate the dynamic evolution of system errors;

[0081] The interference estimation module is used to design an interference observer for online estimation of mismatched and matched interference.

[0082] The tracking control module is used to construct kinematic controllers, filters, and dynamic controllers to achieve robust preset time tracking control of the wheeled mobile robot on the reference trajectory.

[0083] II. Evidence of the Relevant Effects of the Embodiments. The embodiments of the present invention have achieved some positive effects during research and development or use, and indeed possess significant advantages compared to existing technologies. The following description, in conjunction with data, charts, and other materials from the experimental process, illustrates these advantages.

[0084] Simulation Experiment Verification and Analysis: To verify the performance of the preset time control method for the wheeled mobile robot under multiple perturbations designed in this embodiment of the invention, a simulation model was established using Matlab, with the simulation time set to 60 seconds. The controller and observer parameters were set as follows: , , , , , , , , , , .

[0085] To verify the control performance of the algorithm of the present invention under different preset convergence times, the preset convergence time was set to... Second.

[0086] Figure 3 The actual trajectory and reference trajectory curves of a wheeled mobile robot subjected to matched and unmatched interference under different expected convergence times are shown. Figure 4 The tracking error curves of a wheeled mobile robot subjected to matching and mismatch interference under different expected convergence times are shown. Figure 5 The kinematic perturbation estimation error curves for a wheeled robot under different expected convergence times are shown. Figure 6 These are the dynamic perturbation estimation error curves for a wheeled robot under different expected convergence times. Figure 7 These are the control input curves of a wheeled robot under different expected convergence times. Figure 3 This invention demonstrates that the control method designed in this invention can drive a wheeled mobile robot to quickly and accurately track a reference trajectory under both matched and mismatched interference. Figure 4 This demonstrates that the control method designed in this invention enables the position tracking error of a wheeled mobile robot to converge to a small neighborhood near zero within a preset time. Figure 5 and Figure 6 The perturbation observer designed in this invention ensures that the observation error converges to a small neighborhood near zero within a preset convergence time. Figure 7 This demonstrates that the control method designed in this invention can generate a smooth and bounded control input signal, avoiding the problem of needing to generate excessively large control inputs for rapid error convergence.

[0087] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0088] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method and system for preset time control of a wheeled mobile robot under multiple disturbances, characterized in that, The preset time control method for a wheeled mobile robot under multiple disturbances includes the following steps: Step 1: Considering the effects of multiple sources of interference such as roller skating and random external force disturbances, establish a nonlinear motion mathematical model of the wheeled mobile robot under matched and unmatched interference. Step 2: Design a preset time adjustment function to regulate the dynamic evolution of system error; Step 3: Based on the established motion model of the wheeled mobile robot, and by integrating the designed preset time adjustment function, kinematic disturbance observers and dynamic disturbance observers are designed to estimate mismatched and matched disturbances online. Step four: Based on the disturbance estimation information and combined with the preset time adjustment function, construct a kinematic controller, a filter, and a dynamic controller to realize robust preset time tracking control of the wheeled mobile robot on the reference trajectory.

2. The preset time control method for a wheeled mobile robot under multiple disturbances as described in claim 1, characterized in that, The nonlinear motion mathematical model of the wheeled mobile robot affected by matching and mismatch disturbances in step one is as follows: ； In the formula, The position of the robot's center of gravity. Let be the angular velocities of the robot's right and left drive wheels. For the control torque of the robot's right and left wheels, Let be the Jacobian transformation matrix. Here is the robot's mass inertia matrix. For the inertial coupling matrix, and These are the mismatch and match perturbation terms, respectively; for positive constants... and ,exist and .

3. The preset time control method for a wheeled mobile robot under multiple disturbances as described in claim 1, characterized in that, The preset time adjustment function in step two Designed as follows: ； In the formula, To preset the convergence time, It is a constant.

4. The preset time control method for a wheeled mobile robot under multiple disturbances as described in claim 2, characterized in that, The kinematic perturbation observer and the dynamic perturbation observer in step three are designed as follows: ； In the formula, , and These are the estimated values ​​for mismatched interference and matched interference, respectively. and These are the observer states, This is the observer gain.

5. The preset time control method for a wheeled mobile robot under multiple disturbances as described in claim 2, characterized in that, Kinematic controller in step four ,filter and dynamic controller Designed as follows: ； In the formula, For position tracking error, For speed tracking error, For reference trajectory, For the derivative of the reference trajectory, and Design parameters for the filter. For filter control input, To control the gain.

6. A preset time control system for a wheeled mobile robot under multiple disturbances, applying the preset time control method for a wheeled mobile robot under multiple disturbances as described in any one of claims 1 to 5, characterized in that, The preset time control system for the underwater multi-disturbance wheeled mobile robot includes: The model building module is used to analyze the effects of multi-source disturbances such as roller skating and random external force disturbances, and to establish nonlinear motion mathematical models of wheeled mobile robots subjected to matched and unmatched disturbances. The preset time adjustment module is used to design a preset time function to regulate the dynamic evolution of system errors; The interference estimation module is used to design an interference observer for online estimation of mismatched and matched interference. The tracking control module is used to construct kinematic controllers, filters, and dynamic controllers to achieve robust preset time tracking control of the wheeled mobile robot on the reference trajectory.

7. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor performs the steps of the preset time control method for a wheeled mobile robot under multiple disturbances as described in any one of claims 1 to 5.

8. A computer device, characterized in that, The computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it causes the processor to perform the steps of the preset time control method for a wheeled mobile robot under multiple disturbances as described in any one of claims 1 to 5.

Images