Advanced controllers are an excellent choice for the trajectory tracking problem of Wheeled Mobile Robots (WMRs). However, these controllers pose a challenge to the hardware structure of WMRs due to the controller's complex structure and the large number of calculations needed. In that context, designing a controller with a simple structure and a small number of computations but good real-time performance is necessary in order to improve the tracking accuracy for the WMRs without requiring high hardware architecture. In this work, a neural network controller with a simple structure for the trajectory-tracking of a Mecanum-Wheel Mobile robot (MWMR) based on a reference controller is proposed. A two-layer feedforward neural network is designed as a tracking controller for the robot. The neural network is trained with a sample input-output data set so that the error between the neural network output and the reference control signal of the supervisory controller is minimal. The neural network parameters are trained to update over time. The simulation results verified the effectiveness of the neural network controller, whose parameters are tuned adaptively to ensure a fast convergence to the desired Bézier trajectory.
In this article, the research team systematically developed a method to model the kinematics and dynamics of a 3-wheeled robot subjected to external disturbances and sideways wheel sliding. These models will be used to design control laws that compensate for wheel slippage, model uncertainties, and external disturbances. These control algorithms were developed based on dynamic surface control (DSC). An adaptive trajectory tracking DSC algorithm using a fuzzy logic system (AFDSC) and a radial neural network (RBFNN) with a fuzzy logic system were used to overcome the disadvantages of DSC and expand the application domain for non-holonomic wheeled mobile robots with lateral slip (WMR). However, this adaptive fuzzy neural network dynamic surface control (AFNNDSC) adaptive controller ensures the closed system is stable, follows the preset trajectory in the presence of wheel slippage model uncertainty, and is affected by significant amplitude disturbances. The stability and convergence of the closed-loop system are guaranteed based on the Lyapunov analysis. The AFNNDSC adaptive controller is evaluated by simulation on the Matlab/simulink software R2022b and in a steady state. The maximum position error on the right wheel and left wheel is 0.000572 (m) and 0.000523 (m), and the angular velocity tracking error in the right and left wheels of the control method is 0.000394 (rad/s). The experimental results show the theoretical analysis’ correctness, the proposed controller’s effectiveness, and the possibility of practical applications. Orbits are set as two periodic functions of period T as follows.
2 February 2025 in Engineering, Technology & Applied Science Research
This paper examines adaptive control strategies for stabilizing robots, focusing on Li-Slotine adaptive control and Iterative Learning Control (ILC). Both methods handle uncertainties through learning and compensation, ensuring stability and precision. Li-Slotine control, based on Lyapunov theory, dynamically adjusts parameters for asymptotic stability in uncertain systems. ILC improves performance in repetitive tasks by refining control inputs using tracking errors, making it suitable for robotics and manufacturing. While Li-Slotine excels in real-time adaptation and robustness to disturbances, its computational demands challenge high-degree-of-freedom systems. ILC enhances accuracy through iterative learning but is sensitive to noise and requires careful tuning. MATLAB simulations and experimental results demonstrate the effectiveness of both approaches. Future work will explore hybrid frameworks that combine the adaptability of Li-Slotine with the data-driven refinement of ILC to provide robust solutions for complex, dynamic robotic systems.
1 March 2025 in Journal of Robotics and Control (JRC)
The paper introduces an algorithm application of an adaptive Dynamic Sliding Surface Controller that integrates neural networks and fuzzy logic systems with traction tracking for a Mecanum Wheel Mobile Robot. In this framework, neural networks are employed to approximate the uncertain nonlinear numerical aspects of MWMR, while fuzzy logic systems are utilized to adaptively. The stability of the closed-loop system is investigated using the Lyapunov criterion. The proposed controller is verified by numerical simulation. The simulation results show that the proposed controller performs better than the backstepping sliding controller in the case of uncertain model parameters and when there is an impact disturbance.
In this article, the research team has systematically developed a method to model the kinematics and dynamics of a 3-wheeled robot subjected to external disturbances and sideways wheel sliding. These models will be used to design control laws that compensate for wheel slippage, model uncertainties, and external disturbances. These are control algorithms developed based on Dynamic Surface Control (DSC). Adaptive trajectory tracking DSC algorithm using fuzzy logic system (AFDSC) and radial neural network (RBFNN) with fuzzy logic system to overcome the disadvantages of DSC and expand the application domain for wheeled Mobile Robots (WMR). However, this Adaptive Fuzzy Neural Network Dynamic Surface Control (AFNNDSC) adaptive controller ensures the closed system is stable and follows the preset trajectory in the presence of wheel slippage model uncertainty and is affected by significant amplitude disturbances. The stability and convergence of the closed-loop system are guaranteed based on the Lyapunov analysis. The AFNNDSC adaptive controller is evaluated by simulation on MATLAB/Simulink software and in a steady state. The maximum position error on the right wheel and left wheel is 0.000572 (m) and 0.000523 (m), and the angular velocity tracking error in the right and left wheels of the control method is 0.000394 (rad/s). The experimental results show the correctness of the theoretical analysis, the effectiveness of the proposed controller, and the possibility of practical application.