Wheeled Mobile Robot

In this study, the method of direct-motion parallel parking is introduced both in theory and in simulations for the vehicle with and without a trailer. The results show that not only a vehicle with a trailer park in parallel using direct motion, but also a vehicle with a trailer park in parallel in direct motion after the final value of the orientation angle is satisfied. Simulation results are given to verify the effectiveness of the proposed method.

Paper videos can be reached from this URL: http://www.youtube.com/playlist?list=PLENSkat0854vszuVfu9mnrEvHsVQGBBgB

In this study, a Best First Search (BFS) Based Intelligent PID Tuning Method is proposed for a mobile robot path tracking problem. BFS is an informed search strategy in Artificial Intelligence (AI). It has been used in many areas of intelligent systems. Here, it is used to search values of both ultimate period and ultimate gain of Ziegler-Nichols (ZN) PID Tuning Method. So, using these ultimate period and gain, PID parameters can be c from tables of ZN method. The performance measure in this problem is described as minimizing total error during any specified trajectory tracking. Thus the proposed method does not depend on the system model. It only needs error information during the tracking control. So, this method can be used to tune PID parameters of any tracking controller for a system with unknown system dynamics. The proposed method is tested with simulations in MATLAB during trajectory tracking of a mobile robot. In addition, it is compared with classical PID and conventional PID tuning methods including Ziegler-Nichols method, Tyreus-Luyben method, and Shinskey method.

Keywords: Intelligent PID tuning, best first search, autonomous mobile robot, mobile robot path tracking problem, computed torque PID control, dynamic model, Ziegler-Nichols, Tyreus-Luyben, Shinskey.

Purpose-The purpose of this paper is to provide a comprehensive and unified presentation of recent developments in skid-steer wheeled mobile robots (SSWMR) with regard to its control, guidance and navigation for the researchers who wish to study in this field. Design/methodology/approach-Most of the contemporary unmanned ground robot's locomotion is based upon the wheels. For wheeled mobile robots (WMRs), one of the prominent and widely used driving schemes is skid steering. Because of mechanical simplicity and high maneuverability particularly in outdoor applications, SSWMR has an advantage over its counterparts. Different prospects of SSWMR have been discussed including its design, application, locomotion, control, navigation and guidance. The challenges pertaining to SSWMR have been pointed out in detail, which will seek the attention of the readers, who are interested to explore this area. Findings-Relying on the recent literature on SSWMR, research gaps are identified that should be analyzed for the development of autonomous skid-steer wheeled robots. Originality/value-An attempt to present a comprehensive review of recent advancements in the field of WMRs and providing references to the most intriguing studies.

In this paper an observer based adaptive control algorithm is built for wheel mobile robot (WMR) with considering the system uncertainties, input disturbances, and wheel slips. Firstly, the model of the kinematic and dynamic loops is shown with presence of the disturbances and system uncertainties. Next, the adaptive controller for nonlinear mismatched disturbance systems based on the disturbances observer is presented in detail. The controller includes two parts, the first one is for the stability purpose and the later is for the disturbances compensation. After that this control scheme is applied for both two loops of the system. In this paper, the stability of the closed system which consists of two control loops and the convergence of the observers is mathematically analysed based on the Lyapunov theory. Moreover, the proposed model does not require the complex calculation so it is easy for the implementation. Finally, the simulation model is built for presented method and the existed one to verify the correctness and the effectiveness of the proposed scheme. The simulation results show that the introduced controller gives the good performances even that the desired trajectory is complicated and the working condition is hard.

In this paper, we present the modeling and validation of a new family of climbing robots that are capable of adhering to vertical surfaces through permanent magnetic elements. The robotic system is composed of two modules, the master and the follower carts, which are arranged in a sandwich configuration, with the surface to climb interposed between them. Thanks to this configuration, the mobile robot can climb even nonferromagnetic and curved surfaces; moreover, the master cart is capable of freely moving on the floor by detaching from the follower. In this paper, we propose the mathematical modeling, simulation, and experimental validation of this kind of robots, with particular focus on the transitions between floor and climbing motion.

This article presents a summary of applications of chaos and fractals in robotics. Firstly, basic concepts of determin‐ istic chaos and fractals are discussed. Then, fundamental tools of chaos theory used for identifying and quantifying chaotic dynamics will be shared. Principal applications of chaos and fractal structures in robotics research, such as chaotic mobile robots, chaotic behaviour exhibited by mobile robots interacting with the environment, chaotic optimization algorithms, chaotic dynamics in bipedal locomotion and fractal mechanisms in modular robots will be presented. A brief survey is reported and an analysis of the reviewed publications is also presented.

In this study, the method of direct-motion diagonal and perpendicular parking is introduced both in theo-ry and in simulations for the vehicle with and without a trailer. The results show that not only a vehicle with a trailer park in diagonal or perpendicular using direct motion, but also a vehicle with a trailer park in diagonal and perpendicular in direct motion after the final value of the orientation angle is satisfied. Simulation results are given to verify the effec-tiveness of the proposed method.

Keywords: diagonal, perpendicular, direct motion, parking, trailer, car-like vehicle

Paper videos can be reached from this URL: http://www.youtube.com/playlist?list=PLENSkat0854vGceT1fX4Yr6Yw0UqqW_vl

The article addresses a robust control strategy for efficient path tracking of nonholonomic wheeled mobile robot (WMR) based on time delay approach. Depending on the application requirements, nonholonomic WMR system might be subjected to various payloads, which affects the overall system mass, inertia, position of center of mass and other hardware parameters statically or dynamically. Under such circumstances, accurate modeling of nonholonomic robots is difficult and challenging. The proposed controller negotiates uncertainties caused due to payload variations as well as associated disturbances and reduces modeling effort through approximation of the overall uncertainties with a composite function. It has been shown that the controller does not require any bounds on the uncertainties, thus providing unconstrained working paradigm. The controller is proposed for a nonholonomic WMR and its effectiveness is verified through simulation and experimentally while WMR is commanded to track various paths. The superior performance is also noted against adaptive sliding mode control law

... Full paper Variable structure control for a wheeled mobile robot M. BELHOCINE¤, M. HAMERLAIN and F. MERAOUBI Laboratoire de Robotique et d'Intelligence Arti cielle, CDTA, Cité 20 août 1956, BP 17, Baba-Hassen, Alger, Algérie ... Page 2. 910 M. Belhocine et al. ...

ABSTRACT In this paper a fuzzy control and an obstacle avoidance system, together with a distributed system of embedded microcontrollers, are presented. In the real-time control, a wheeled mobile robot (WMR), PeopleBot from Mobile Robots, has been used. The solution adopted can be easily ported for the implementation of an intelligent wheelchair, capable either to carry an elderly or disabled person, or to move independently in a smart environment, as a sensorial extension of the assisted individual. A number of control modules are located on the mobile robot, while others are deployed in an intelligent environment. This solution can significantly reduce the cost of developing a robotic assistant for the elderly and disabled. The structure of the real-time setup is described in detail, as well as the main algorithms used for each individual task: path following, obstacle avoidance, data acquisition. Also, an obstacle avoidance system, based on ricochet method, named “the bubble rebound method”, is presented.

Abstract: Through two di erent approaches, this report proposes two gen-eral controllers for unicycle-type and two-steering-wheels mobile robots. For both systems, conditions for asymptotical convergence to a prede ned path are established and simulation results are presented. ...

In this paper we address the problem of synthesizing simple rules and local interactions at the individual level so that pre-specified complex behavior emerges at the group level of a collection of autonomous mobile agents. Usually, the emergent collective behavior is used to perform certain spatial group-tasks. Specifically, we consider self-assembling of a group of mobile robots into grid, line, and wedge patterns. We introduce the notion of local-templates in which each mobile agent – capable of simple forward/backward movements and a clock-wise/counter clock-wise spin – actively encodes distinctive information into multiple non-overlapping sectorial regions of the surrounding environment in order to form pose-specific virtual links with similar minimalist agents in a local neighborhood. The resulting local patterns around each agent lead to the desired global formation. In order to take mobile robots closer to their biological counterparts, there is a need to further simplify the manner in which they currently perceive their surroundings, communicate with their neighbors, and compute their actions. We have built a robotic platform consisting of four wheeled-mobile robots that are christened as Kinbots. They are similar in principle to Braitenberg Vehicles and use simple perception/interaction/actuation techniques to achieve individual vehicle complexity and produce effective group behavior through cooperation. To validate the proposed approach, we demonstrate a column-formation task in computer simulations and physical experiments. We illustrate an experiment which is representative of various prominent stages in a group-formation task such as formation-achievement, maintenance, and response of formation movement to the presence of obstacles.

Numerical simulation analysis of the motion of wheeled mobile robots is significant for both their R&D and control phases, especially due to the recent increase in the number of planetary exploration missions. Using the position/orientation of the rover body and all the joint angles as generalized coordinates, the Jacobian matrices and recursive dynamic models are derived. Terramechanics models for calculating the forces and moments that act on the wheel-as a result of the deformable soil-are introduced in consideration of the effect of normal force. A rough terrain modeling method is developed for estimating the wheel-soil interaction area, wheel sinkage, and the terminal coordinate. A simulation program that includes the above techniques is developed using Matlab and SpaceDyn Toolbox. Experimental results from a 4-wheeled mobile robot moving on Toyoura soft sand are used to verify the fidelity of the simulation. A simulation example of a robot moving on a random rough terrain is also presented.

In this paper, the tracking control problem
of a class of uncertain Euler–Lagrange systems subjected
to time-varying input delay and bounded disturbances
is addressed. To this front, a novel delay dependent
control law referred as adaptive robust
outer loop control (AROLC) is proposed. Compared to
the conventional predictor-based approaches, the proposed
controller is capable of negotiating any input
delay, within a stipulated range, without knowing the
delay variation. The maximum allowable input delay
is computed through Razumikhin-type stability analysis.
AROLC also provides robustness against the disturbances
due to the input delay, parametric variations
and unmodelled dynamics through switching control
law. The novel adaptive law allows the switching gain
to modify itself online in accordance with the tracking
error without any prerequisite of the uncertainties.
The uncertain system, employing AROLC, is shown to
be uniformly ultimately bounded. As a proof of concept,
experimentation is carried out on a nonholonomic
wheeled mobile robot with various time varying as well
as fixed input delay, and better tracking accuracy of
the proposed controller is noted compared to predictor based
methodology.

In this paper, we present the modeling and validation of a new family of climbing robots that are capable of adhering to vertical surfaces through permanent magnetic elements. The robotic system is composed of two modules, the master and the follower carts, which are arranged in a sandwich configuration, with the surface to climb interposed between them. Thanks to this configuration, the mobile robot can climb even nonferromagnetic and curved surfaces; moreover, the master cart is capable of freely moving on the floor by detaching from the follower. In this paper, we propose the mathematical modeling, simulation, and experimental validation of this kind of robots, with particular focus on the transitions between floor and climbing motion.

This paper proposes an intelligent controller for motion control of robotic systems to obtain high precision tracking without the need for a real-time trial and error method. In addition, a new self-tuning algorithm has been developed based on both the ant colony algorithm and a fuzzy system for real-time tuning of controller parameters. Simulations and experiments using a real robot have been addressed to demonstrate the success of the proposed controller and validate the theoretical analysis. Obtained results confirm that the proposed controller ensures robust performance in the presence of disturbances and parametric uncertainties without the need for adjustment of control law parameters by a trial and error method.