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Article
Publication date: 4 November 2014

Mohammad Mehdi Fateh and Ali Asghar Arab

The uncertainty and nonlinearity are the challenging problems for the control of a nonholonomic wheeled mobile robot. To overcome these problems, many valuable methods…

Abstract

Purpose

The uncertainty and nonlinearity are the challenging problems for the control of a nonholonomic wheeled mobile robot. To overcome these problems, many valuable methods have been proposed by using two control loops namely the kinematic control and the torque control so far. In majority of the proposed approaches the dynamics of actuators is omitted for simplicity in the control design. This drawback degrades the control performance in high-velocity tracking control. On the other hand, to guarantee stability and overcome uncertainties, the control methods become computationally extensive and may be impractical due to using all states. The purpose of this paper is to design a simple controller with guaranteed stability for overcoming the nonlinearity, uncertainty and actuator dynamics.

Design/methodology/approach

The control design includes two control loops, the kinematic control loop and the novel dynamic control loop. The dynamic control loop uses the voltage control strategy instead of the torque control strategy. Feedbacks of the robot orientation, robot position, robot linear and angular velocity, and motor currents are given to the control system.

Findings

To improve the precision, the dynamics of motors are taken into account. The most important advantages of the proposed control law is that it is free from the robot dynamics, thereby the controller is simple, fast response and robust with ignorable tracking error. The control approach is verified by stability analysis. Simulation results show the effectiveness of the proposed control applied on an uncertain nonholonomic wheeled mobile robot driven by permanent magnet dc motors. A comparison with an adaptive sliding-mode dynamic control approach confirms the superiority of the proposed approach in terms of precision, simplicity of design and computations.

Originality/value

The originality of the paper is to present a new control design for an uncertain nonholonomic wheeled mobile robot by using voltage control strategy in replace of the torque control strategy. In addition, a novel state-space model of electrically driven nonholonomic wheeled mobile robot in the workspace is presented.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 7 no. 4
Type: Research Article
ISSN: 1756-378X

Keywords

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Article
Publication date: 13 December 2017

Ali Alouache and Qinghe Wu

The aim of this paper is to propose a robust robot fuzzy logic proportional-derivative (PD) controller for trajectory tracking of autonomous nonholonomic differential…

Abstract

Purpose

The aim of this paper is to propose a robust robot fuzzy logic proportional-derivative (PD) controller for trajectory tracking of autonomous nonholonomic differential drive wheeled mobile robot (WMR) of the type Quanser Qbot.

Design/methodology/approach

Fuzzy robot control approach is used for developing a robust fuzzy PD controller for trajectory tracking of a nonholonomic differential drive WMR. The linear/angular velocity of the differential drive mobile robot are formulated such that the tracking errors between the robot’s trajectory and the reference path converge asymptotically to zero. Here, a new controller zero-order Takagy–Sugeno trajectory tracking (ZTS-TT) controller is deduced for robot’s speed regulation based on the fuzzy PD controller. The WMR used for the experimental implementation is Quanser Qbot which has two differential drive wheels; therefore, the right/left wheel velocity of the differential wheels of the robot are worked out using inverse kinematics model. The controller is implemented using MATLAB Simulink with QUARC framework, downloaded and compiled into executable (.exe) on the robot based on the WIFI TCP/IP connection.

Findings

Compared to other fuzzy proportional-integral-derivative (PID) controllers, the proposed fuzzy PD controller was found to be robust, stable and consuming less resources on the robot. The comparative results of the proposed ZTS-TT controller and the conventional PD controller demonstrated clearly that the proposed ZTS-TT controller provides better tracking performances, flexibility, robustness and stability for the WMR.

Practical implications

The proposed fuzzy PD controller can be improved using hybrid techniques. The proposed approach can be developed for obstacle detection and collision avoidance in combination with trajectory tracking for use in environments with obstacles.

Originality/value

A robust fuzzy logic PD is developed and its performances are compared to the existing fuzzy PID controller. A ZTS-TT controller is deduced for trajectory tracking of an autonomous nonholonomic differential drive mobile robot (i.e. Quanser Qbot).

Details

Industrial Robot: An International Journal, vol. 45 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 10 May 2018

Guo Yi, Jianxu Mao, Yaonan Wang, Hui Zhang and Zhiqiang Miao

The purpose of this paper is to consider the leader-following formation control problem for nonholonomic vehicles based on a novel biologically inspired neurodynamics approach.

Abstract

Purpose

The purpose of this paper is to consider the leader-following formation control problem for nonholonomic vehicles based on a novel biologically inspired neurodynamics approach.

Design/methodology/approach

The interactions among the networked multi-vehicle system is modeled by an undirected graph. First, a distributed estimation law is proposed for each follower vehicle to estimate the state including the position, orientation and linear velocity of the leader. Then, a distributed formation tracking control law is designed based on the estimated state of the leader, where a bio-inspired neural dynamic is introduced to solve the impractical velocity jumps problem. Explicit stability and convergence analyses are presented using Lyapunov tools.

Findings

The effectiveness and efficiency of the proposed control law are demonstrated by numerical simulations and physical vehicle experiments. Consequently, the proposed protocol can successfully achieve the desired formation under connected topologies while tracking the trajectory generated by the leader.

Originality/value

This paper proposes a neurodynamics-based leader–follower formation tracking algorithm for multiple nonholonomic vehicles.

Details

Assembly Automation, vol. 38 no. 5
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 14 August 2018

Hua Chen, Lei Chen, Qian Zhang and Fei Tong

The finite-time visual servoing control problem is considered for dynamic wheeled mobile robots (WMRs) with unknown control direction and external disturbance.

Abstract

Purpose

The finite-time visual servoing control problem is considered for dynamic wheeled mobile robots (WMRs) with unknown control direction and external disturbance.

Design/methodology/approach

By using finite-time control method and switching design technique.

Findings

First, the visual servoing kinematic WMR model is developed, which can be converted to the dynamic chained-form systems by using a state and input feedback transformation. Then, for two decoupled subsystems of the chained-form systems, according to the finite-time stability control theory, a discontinuous three-step switching control strategy is proposed in the presence of uncertain control coefficients and external disturbance.

Originality/value

A class of discontinuous anti-interference control method has been presented for the dynamic nonholonomic systems.

Details

Assembly Automation, vol. 38 no. 5
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 4 March 2019

Yu Qiu, Baoquan Li, Wuxi Shi and Yimei Chen

The purpose of this paper is to present a visual servo tracking strategy for the wheeled mobile robot, where the unknown feature depth information can be identified…

Abstract

Purpose

The purpose of this paper is to present a visual servo tracking strategy for the wheeled mobile robot, where the unknown feature depth information can be identified simultaneously in the visual servoing process.

Design/methodology/approach

By using reference, desired and current images, system errors are constructed by measurable signals that are obtained by decomposing Euclidean homographies. Subsequently, by taking the advantage of the concurrent learning framework, both historical and current system data are used to construct an adaptive updating mechanism for recovering the unknown feature depth. Then, the kinematic controller is designed for the mobile robot to achieve the visual servo trajectory tracking task. Lyapunov techniques and LaSalle’s invariance principle are used to prove that system errors and the depth estimation error converge to zero synchronously.

Findings

The concurrent learning-based visual servo tracking and identification technology is found to be reliable, accurate and efficient with both simulation and comparative experimental results. Both trajectory tracking and depth estimation errors converge to zero successfully.

Originality/value

On the basis of the concurrent learning framework, an adaptive control strategy is developed for the mobile robot to successfully identify the unknown scene depth while accomplishing the visual servo trajectory tracking task.

Details

Assembly Automation, vol. 39 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 27 April 2012

Yu Yu Lwin and Yoshio Yamamoto

The purpose of this paper is to design a mobile robot controller which is able to pursue a given goal with obstacle‐avoiding capability in which the two tasks, i.e. aiming…

Abstract

Purpose

The purpose of this paper is to design a mobile robot controller which is able to pursue a given goal with obstacle‐avoiding capability in which the two tasks, i.e. aiming at the goal and avoiding obstacles, are fused together in a coherent framework of look‐ahead control method.

Design/methodology/approach

Navigation toward a goal is typically executed based on global information obtained from GPS. Obstacle avoidance, however, is local in nature, and a higher priority temporarily should be placed on avoiding a collision with the obstacle than taking the shortest path toward the goal. The former is handled by the goal‐aiming mode while the latter is dealt with by the obstacle‐avoiding mode. These two tasks with different natures are treated under so‐called “look‐ahead control” by simply changing coordinate frames and associated elements within the same controller. Therefore, continuity and smoothness of the resulting motion and trajectory is maintained throughout its mission.

Findings

Two different tasks, goal aiming and collision avoiding, can smoothly be switched back and forth within the same controller by replacing its coordinate frame, decoupling matrix and corresponding reference signals to follow. It is found through simulation and real experiments that the proposed scheme can graciously handle obstacles, static or dynamic, regardless of the number of obstacles. Also, the look‐ahead control guarantees smoothness of resulting trajectories.

Originality/value

Mobile robot autonomous navigation in outdoor obstructed areas offers challenging study for robot researchers. The vital aspect is to smartly control the mobile robot to move to the desired location autonomously, without colliding with any obstacles. The proposed method provides a stable and robust navigation framework for any kind of mobile robot, especially for outdoor use.

Details

Industrial Robot: An International Journal, vol. 39 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 7 July 2020

Jiehao Li, Junzheng Wang, Shoukun Wang, Hui Peng, Bomeng Wang, Wen Qi, Longbin Zhang and Hang Su

This paper aims on the trajectory tracking of the developed six wheel-legged robot with heavy load conditions under uncertain physical interaction. The accuracy of…

Abstract

Purpose

This paper aims on the trajectory tracking of the developed six wheel-legged robot with heavy load conditions under uncertain physical interaction. The accuracy of trajectory tracking and stable operation with heavy load are the main challenges of parallel mechanism for wheel-legged robots, especially in complex road conditions. To guarantee the tracking performance in an uncertain environment, the disturbances, including the internal friction, external environment interaction, should be considered in the practical robot system.

Design/methodology/approach

In this paper, a fuzzy approximation-based model predictive tracking scheme (FMPC) for reliable tracking control is developed to the six wheel-legged robot, in which the fuzzy logic approximation is applied to estimate the uncertain physical interaction and external dynamics of the robot system. Meanwhile, the advanced parallel mechanism of the electric six wheel-legged robot (BIT-NAZA) is presented.

Findings

Co-simulation and comparative experimental results using the BIT-NAZA robot derived from the developed hybrid control scheme indicate that the methodology can achieve satisfactory tracking performance in terms of accuracy and stability.

Originality/value

This research can provide theoretical and engineering guidance for lateral stability of intelligent robots under unknown disturbances and uncertain nonlinearities and facilitate the control performance of the mobile robots in a practical system.

Details

Assembly Automation, vol. 40 no. 5
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 27 April 2012

Yaonan Wang and Xiru Wu

The purpose of this paper is to present the radial basis function (RBF) networks‐based adaptive robust control for an omni‐directional wheeled mobile manipulator in the…

Abstract

Purpose

The purpose of this paper is to present the radial basis function (RBF) networks‐based adaptive robust control for an omni‐directional wheeled mobile manipulator in the presence of uncertainties and disturbances.

Design/methodology/approach

First, a dynamic model is obtained based on the practical omni‐directional wheeled mobile manipulator system. Second, the RBF neural network is used to identify the unstructured system dynamics directly due to its ability to approximate a nonlinear continuous function to arbitrary accuracy. Using the learning ability of neural networks, RBFNARC can co‐ordinately control the omni‐directional mobile platform and the mounted manipulator with different dynamics efficiently. The implementation of the control algorithm is dependent on the sliding mode control.

Findings

Based on the Lyapunov stability theory, the stability of the whole control system, the boundedness of the neural networks weight estimation errors, and the uniformly ultimate boundedness of the tracking error are all strictly guaranteed.

Originality/value

In this paper, an adaptive robust control scheme using neural networks combined with sliding mode control is proposed for crawler‐type mobile manipulators in the presence of uncertainties and disturbances. RBF neural networks approximate the system dynamics directly and overcome the structured uncertainty by learning. Based on the Lyapunov stability theory, the stability of the whole control system, the boundedness of the neural networks weight estimation errors, and the uniformly ultimate boundedness of the tracking error are all strictly guaranteed.

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Article
Publication date: 13 May 2014

Qing Tang

The purpose of this paper is to design the localization and tracking algorithms for our mobile welding robot to carry out the large steel structure welding operations in…

Abstract

Purpose

The purpose of this paper is to design the localization and tracking algorithms for our mobile welding robot to carry out the large steel structure welding operations in industrial environment.

Design/methodology/approach

Extended Kalman filter, considering the bicycle-modeled robot, is adopted in the localization algorithm. The position and orientation of our mobile welding robot is estimated using the feedback of the laser sensor and the robot motion commands history. A backstepping variable is involved in the tracking algorithm. By introducing a specifically selected Lyapunov function, we proved the tracking algorithm using Barbalat Lemma, which leads the errors of estimated robot states to converge to zero.

Findings

The experiments show that the proposed localization method is fast and accurate and the tracking algorithm is robust to track straight lines, circles and other typical industrial curve shapes. The proposed localization and tracking algorithm could be used, but not limited to the mobile welding.

Originality/value

Localization problem which is neglected in previous research is very important in mobile welding. The proposed localization algorithm could estimate the robot states timely and accurately, and no additional sensors are needed. Furthermore, using the estimated robot states, we proposed and proved a tracking algorithm for bicycle-modeled mobile robots which could be used in welding as well as other industrial operation scenarios.

Details

Industrial Robot: An International Journal, vol. 41 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 17 September 2019

Pouya Panahandeh, Khalil Alipour, Bahram Tarvirdizadeh and Alireza Hadi

Trajectory tracking is a common problem in the field of mobile robots which has attracted a lot of attention in the past two decades. Therefore, besides the search for new…

Abstract

Purpose

Trajectory tracking is a common problem in the field of mobile robots which has attracted a lot of attention in the past two decades. Therefore, besides the search for new controllers to achieve a better performance, improvement and optimization of existing control rules are necessary. Trajectory tracking control laws usually contain constant gains which affect greatly the robot’s performance.

Design/methodology/approach

In this paper, a method based on neural networks is introduced to automatically upgrade the gains of a well-known trajectory tracking controller of wheeled mobile robots. The suggested method speeds up the convergence rate of the main controller.

Findings

Simulations and experiments are performed to assess the ability of the suggested scheme. The obtained results show the effectiveness of the proposed method.

Originality/value

In this paper, a method based on neural networks is introduced to automatically upgrade the gains of a well-known trajectory tracking controller of wheeled mobile robots. The suggested method speeds up the convergence rate of the main controller.

Details

Industrial Robot: the international journal of robotics research and application, vol. 46 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

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