Wheeled Mobile Robot Research Articles

Distributed Robust Fault Estimation for Multiagent Systems Based on Transition Variable Estimator.

This article investigates the distributed robust fault estimation for a class of multiagent systems with actuator faults and nonlinear uncertainties. To estimate the actuator faults and system states simultaneously, a novel transition variable estimator is constructed. Compared with existing similar results, the fault estimator existing condition is not necessary for designing the transition variable estimator. Furthermore, the bounds of the faults and their derivatives can be unknown in designing the estimator for each agent in the system. The parameters of the estimator are calculated by using Schur decomposition and linear matrix inequality algorithm. Finally, the performance of the proposed method is demonstrated through experiments of wheeled mobile robots.

Event-Based Adaptive Fault Tolerant Control and Collision Avoidance of Wheel Mobile Robots With Communication Limits

Event-Based Adaptive Fault Tolerant Control and Collision Avoidance of Wheel Mobile Robots With Communication Limits

Load Pushing Capacity Analysis of Individual and Multi-Cooperative Mobile Robot through Symbiotic Application

Certain missions require multiple mobile robots working together to accomplish it. There is a need, however, to determine the optimal configuration of modular mobile robots doing cooperative tasks to ensure high utilization and efficiency rate of the individual robot. This study proposed the use of a biosystem-inspired approach in assessing the influence of multiple robots on each other in performing a cooperative pushing task. The kinematics of pushing interaction at a single contact point was first discussed in the study to provide a solid foundation of the mission to be analyzed. Various dimensions in an experimental setup were also covered to better understand how these contribute to planar pushing. Through the resulting symbiotic coefficient, the study was able to determine the optimal configuration among the two, four, and six wheeled mobile robots pushing an object with various loads. While the dominant coefficient for symbiotic relationship was classified as beneficial and only one was neutral, the decline in coefficient values of the 3rd configuration (six wheeled) with respect to the 2nd configuration (4 wheeled) implies possible negative coefficient in the next configuration (8 wheeled). The maximum level of distance at which an object can be pushed was also obtained. This was called the state of plateau wherein adding another module is no longer suggested as it will not improve the pushing capacity any further. Knowing these key points significantly helps in ensuring cost and work efficiency of a given configuration in performing different missions.

Fixed-Time Tracking Control of Wheel Mobile Robot in Slipping and Skidding Conditions

Fixed-Time Tracking Control of Wheel Mobile Robot in Slipping and Skidding Conditions

Tracking control of wheeled mobile robots via intermittent control.

This paper was concerned with the trajectory tracking control of wheeled mobile robots using aperiodic intermittent control. By establishing the corresponding motion model of the wheeled mobile robot, a tracking control strategy was proposed based on the intermittent control approach and backstepping method. Compared to the controllers using continuous state feedback, the proposed control strategy was activated only on separate time intervals, which combined the features of closed- and open-loop control. An example was given to illustrate the effectiveness of the obtained result.

Fixed-Time Formation Control of Multiple Wheeled Mobile Robots for Circumnavigating a Moving Target

Fixed-Time Formation Control of Multiple Wheeled Mobile Robots for Circumnavigating a Moving Target

Reinforcement Learning-Based Tracking Control for a Three Mecanum Wheeled Mobile Robot.

This brief investigates the robust optimal tracking control for a three Mecanum wheeled mobile robot (MWMR) with the external disturbance by the aid of online actor-critic synchronous learning algorithm. The Euler-Lagrange motion equation of MWMR subject to slipping is established by analyzing the structural characteristics of Mecanum wheels. Concatenating the tracking error with the desired trajectory, the tracking control problem is converted into a time-invariant optimal control problem of an augmented system. Then, an approximate optimal tracking controller is obtained by applying online actor-critic synchronous learning algorithm. With the help of Lyapunov-based analysis, the ultimately bounded tracking can be guaranteed. Finally, simulation results show the effectiveness of synchronous learning algorithm and approximate optimal tracking controller.

Adaptive terminal sliding mode control of a non-holonomic wheeled mobile robot

Adaptive terminal sliding mode control of a non-holonomic wheeled mobile robot

Mecanum wheel mobile platform for rapid prototyping of the autonomous control algorithms

This article describes the author’s design of the Mecanum wheel mobile robots (MWR), which can be used as a test platform for experimental research into the development and implementation of autonomous systems. The paper contains a literature review of the subject matter and describes the mechanical actuator subsystem and electronic and information subsystem of the mobile robot solution. The robot was navigated using a minicomputer equipped with a Jetson Nano chip. The robot’s navigation system was implemented using the ROS environment through high-level software. Software modularity is desirable in circuits intended for research and rapid prototyping. This allows for easier modification and maintenance. The microcontroller has been implemented with a DC drive control system and incremental encoder support to estimate robot position using odometry. The project utilizes the Jetson Nano for processing data from distance sensors and monitoring the robot’s performance. The mobile platform is equipped with a RGB-D camera (Microsoft Kinect 360), the robot can use this to perform 3D mapping of the environment. A LiDAR sensor is used to collect data from a two-dimensional space. Laboratory tests were carried out to test the validity of the solutions adopted in the design of the Mecanum-wheeled mobile robot’s navigation system configuration.

InPTC: Integrated Planning and Tube-Following Control for Prescribed-Time Collision-Free Navigation of Wheeled Mobile Robots

InPTC: Integrated Planning and Tube-Following Control for Prescribed-Time Collision-Free Navigation of Wheeled Mobile Robots

Retracted: Distributed Consensus Algorithm for Nonholonomic Wheeled Mobile Robot

Retracted: Distributed Consensus Algorithm for Nonholonomic Wheeled Mobile Robot

Hybrid Approach to implement adaptive Neuro-Fuzzy Inference system for Trajectory Tracking navigation control of a wheeled mobile robot

Hybrid Approach to implement adaptive Neuro-Fuzzy Inference system for Trajectory Tracking navigation control of a wheeled mobile robot

A novel saturated PID‐type observer‐based controller for wheeled mobile robots with a guaranteed performance considering path curvature

AbstractThis article proposes a novel saturated PID‐type formation controller for a class of nonholonomic wheeled mobile robots (WMRs) of type (m, s) with mobility m and steerability s. Since the path curvature causes a severe deviation of the followers from the leaders' trajectory in the corners, a new definition of output equations is suggested to construct the coordinates of a virtual reference point in the front of each follower based on the concept of the extended look‐ahead control that utilizes a corrective angle to compensate the trajectory curvature efficiently. A nonlinear transformation and the robot's kinematic and dynamic equations are heuristically combined to develop a novel second‐order Euler–Lagrange formulation of unconstrained errors from constrained errors. Then, a novel saturated PID‐type controller is proposed for WMRs to build a desirable formation with a prescribed performance. An innovative nonlinear observer is presented to estimate followers' velocities. An efficient mixture of a radial basis function neural network (RBFNN) and an adaptive mechanism is proposed to compensate for model uncertainties, external disturbances, and network approximation errors. Lyapunov's direct method verifies semi‐global uniform ultimate boundedness stability by estimating a gain‐dependent region of attraction. Numerical simulations finally show the efficiency of the proposed controller.

Cooperative game-oriented optimal robust control for an uncertain wheeled mobile robot with position constraints

The trajectory tracking control performance of the wheeled mobile robot (WMR) is subject to position constraints, system uncertainties, and external disturbances. This paper explores the mechanism of the position constraints (equality and inequality) and considers the system uncertainties to be time-varying but bounded with fuzzy prescribed bounds. To solve the position constraints and uncertainties problems, a cooperative game-oriented optimal robust control method is proposed to provide high-precision, fast-response performance and robustness for WMR. First, a creative diffeomorphism transformation is proposed to convert the bounded state variables (subject to inequality constraints) into unbounded state variables. Accordingly, a restructured WMR system with the new state variables is established, which is free from inequality constraints. The uncertainties’ bound is described as a fuzzy number by employing fuzzy set theory, which builds the fuzzy dynamic system of the WMR. Second, the control goal for this study is to drive the WMR to follow the position constraints despite uncertainties. An optimal robust control is developed to guarantee that the tracking errors of the WMR converge to a predefined neighborhood of origin. Using Lyapunov stability analysis, a fuzzy performance index is constructed, including steady-state performance, time performance, and control effort. The fuzzy performance index is employed as the cost function based on the cooperative game theory. The optimal control design is formulated to seek the Pareto-optimal solution of control parameters. Finally, the stability analysis and comparative experiments demonstrate that the proposed control algorithm can ensure the WMR’s superior trajectory tracking convergence performance and strong robustness against uncertainties/disturbances.

Event-Triggered Model-Free Adaptive Control for Wheeled Mobile Robot With Time Delay and External Disturbance Based on Discrete-Time Extended State Observer

Abstract In this paper, an improved model-free adaptive control strategy is proposed for the trajectory tracking problem of the wheeled mobile robot (WMR) with time-delay and bounded disturbance. Firstly, the original nonlinear time delay system is transformed into a data model by applying the full-form dynamic linearization method (FFDL). Secondly, the discrete-time extended state observer (DESO) is applied to estimate the unknown residual nonlinear time-varying term. A full-form dynamic linearization model-free adaptive control scheme based on discrete-time extended state observer (DESO-based FFDL MFAC) is proposed. In addition, a full-form dynamic linearization event-triggered model-free adaptive control based on discrete-time extended state observer (DESO-based FFDL ET-MFAC) is established by designing an event-triggering condition to assure Lyapunov stability. The control input signal is updated only if the system indicator meets the provided event-triggering condition; otherwise, the control input remains unchanged which can address limited communication bandwidth effectively. Finally, the effectiveness of the proposed method is verified by simulation.

Event-Based Wireless Tracking Control for a Wheeled Mobile Robot Against Reactive Jamming Attacks

In this paper, an event-based defense strategy is studied for a wireless remote tracking control system of a wheeled mobile robot suffering from reactive jamming attacks. First, utility functions of both the reactive jammer and control center are established based on the signal to interference plus noise ratio and residual energies. Then, interactions between the reactive jammer and control center are described through a Stackelberg game scheme, for which the existence and uniqueness of the game equilibrium solution are guaranteed. To defend this type of attacks, an event-driven communication scheme is proposed to save transmission energies at the control center. By making full use of the saved energies, a retransmission mechanism is employed to improve the reliability of the communication. Meanwhile, the unavailable data are estimated for both the robot and control center by proposing a model-based estimation method. With the combination of the event-driven communication scheme, the retransmission mechanism and the estimation method, an event-based defense strategy is established. It can be shown that the states of tracking error system under the reactive jamming attacks is guaranteed to be stochastically ultimately bounded (SUB). Finally, the efficiency of the proposed scheme is verified by simulation results.

Tracking controller for uncertain wheel mobile robot: adaptive sliding mode control approach

This paper presents a technique for developing a sliding mode controller (SMC) using the state model of wheel mobile robot (WMR). The control scheme which consists of a controller and a disturbances observer can eliminate system uncertainties, disturbances, and unknown wheel slips. To successfully implement the sliding mode tracking controller algorithm, first, the transformation is utilized to convert the kinematic and dynamic models to an equation of state, and then create a controller based on Lyapunov function. Subsequently, a disturbance observer is formulated based on a stable sliding surface, followed by the development of an adaptive sliding mode control (ASMC) for the system. Moreover, to verify the efficacy of the given strategy, simulations have been performed under the aforementioned disturbance conditions. Finally, the simulation results show that chattering effect is eliminated, and the impact of disturbances is also diminished, thus proving the viability and correctness of the proposed control algorithm.

Hybrid Dynamic Event-Triggered Tracking Control of Wheeled Mobile Robots Against Stochastic DoS Attacks

Hybrid Dynamic Event-Triggered Tracking Control of Wheeled Mobile Robots Against Stochastic DoS Attacks

Concurrent Learning-Based Neuroadaptive Robust Tracking Control of Wheeled Mobile Robot: An Event-Triggered Design

In this paper, an event-based neuro-adaptive robust tracking controller for a perturbed and networked differential drive mobile robot (DMR) is designed with concurrent learning. A radial basis function neural network, which approximates an unknown perturbation, is used to design an adaptive sliding mode controller (SMC). The RBFNN weights and SMC parameters are estimated online using an adaptive tuning law to ensure performance with reduced chattering. To improve the convergence of RBFNN weight estimation error, a concurrent learning-based adaptive law is derived, which uses measured online and recorded data. Further, a suitable triggering condition is designed to achieve a reduced number of control computations while minimizing network resources without sacrificing the stability of the sampled data closed-loop control system. A finite sampling frequency is guaranteed for the designed triggering condition by establishing a positive lower bound on the inter-event execution time which is equivalent to the Zeno-free behaviour of the system. Finally, the proposed event-based neuro-adaptive robust controller is implemented on a practical system (Q-bot 2e) to show the effectiveness of the proposed design.

Formation control of nonholonomic wheeled mobile robots using adaptive distributed fractional order fast terminal sliding mode control

Formation control of nonholonomic wheeled mobile robots using adaptive distributed fractional order fast terminal sliding mode control