共查询到20条相似文献,搜索用时 15 毫秒
1.
Xin Yang Keigo Watanabe Kiyotaka Izumi Kazuo Kiguchi 《International journal of control》2013,86(10):949-963
In this paper, we propose a decentralized control system for transporting a single object by multiple non-holonomic mobile robots. Each agent used in the proposed system has two arms, which can steer around a joint offset from the centre point between two driving wheels. One of these mobile robots acts as a leader, who is assumed to be able to plan and to manipulate the omnidirectional motion of the object by using a resolved velocity control. Other robots, referred to as followers, cooperatively transport the object by keeping a constant relative position with the object using a simple PI control. Different from conventional leader–follower type systems that transport an object by multiple robots in coordination, the present followers can plan an action based on their local coordinate and need no absolute positional information. In addition, as a special case, a system consisting of only two robots is introduced, in which the follower robot not only has an arm length controller to follow the leader but also has a fuzzy controller as an avoidance controller to avoid obstacles or a posture controller to keep a desired posture of the object. Simulation results are given to demonstrate the good performance of the proposed systems. 相似文献
2.
Dayal Ramakrushna Parhi Saroj Kumar Pradhan Anup Kumar Panda Rabindra Kumar Behera 《Applied Soft Computing》2009,9(2):477-487
Intelligent path planning of multiple mobile robots has been addressed in this paper. Cooperative behaviour can be achieved using several mobile robots, which require online inter-communication among themselves. In the present investigation rule-based and rule-based-neuro-fuzzy techniques are analyzed for multiple mobile robots navigation in an unknown or partially known environment. The final aims of the robots are to reach some pre-defined goals. Based upon a reference motion, direction; distances between the robots and obstacles; distances between the robots and targets; different types of rules are taken heuristically and refined later to find the steering angle. The control system combines a repelling influence related to the distance between robots and nearby obstacles and with an attracting influence between the robots and targets. Then a hybrid rule-based-neuro-fuzzy technique is analyzed to find the steering angle of the robots. Results show that the proposed rule-based-neuro-fuzzy technique can improve navigation performance in complex and unknown environments compared to this simple rule-based technique. 相似文献
3.
《Advanced Robotics》2013,27(9):1027-1040
The main goal of this paper is to define, study and analyze a remote control architecture for a set of non-holonomic robotic vehicles. This project gathers three laboratories and the French Army Research Office. Each of these laboratories deals with a part of this multidisciplinary project which includes coordinated control, control architecture, control with time delay and monitoring of the wireless network. In this paper, we present the whole goal of this project including the basic experimental setup developed to validate our control algorithm. We also focus on a new decentralized control strategy that uses the Leader–Follower principle. The originality of this paper stems from the use of the signal level of wireless connection as a control vector. Indeed, each vehicle is fitted with two wireless devices. One of them is equipped with a sector antenna fitted on a DC motor to track the direction of best reception. Thus, it allows us to find the relative angular position of the Follower pointing out the Leader. Using wireless technology as a sensor, instead of vision for instance, allows a longer distance of the coordinated control loop between each vehicle (approximately 100 m) even if GPS information is not available. 相似文献
4.
A distributed motion coordination strategy for multiple nonholonomic mobile robots in cooperative hunting operations 总被引:1,自引:0,他引:1
Hiroaki 《Robotics and Autonomous Systems》2003,43(4):257-282
This paper presents a distributed smooth time-varying feedback control law for coordinating motions of multiple nonholonomic mobile robots of the Hilare-type to capture/enclose a target by making troop formations. This motion coordination is a cooperative behavior for security against invaders in surveillance areas. Each robot in this control law has its own coordinate system and it senses a target/invader, other robots and obstacles, to achieve this cooperative behavior without making any collision. Each robot especially has a two-dimensional control input referred to as a “formation vector” and the formation is controllable by the vectors. The validity of this control law is supported by computer simulations. 相似文献
5.
A hybrid navigation strategy is proposed in this paper for solving the navigation problem of multiple mobile robots. The proposed strategy integrates three algorithms that represent three different types of existing methods in a layered system. The bottom-up architecture of this system is the main contribution of this paper. This architecture pursues reliable low-level layers that can independently work in as much cases as possible, and the high-level layer is used only when it is necessary for guaranteeing convergence in complex situations. The simulation results show that the proposed strategy has well combined the algorithms of different types from the perspective of pursuing reactivity in the premise of ensuring convergence. Compared with the traditional top-down hybrid architecture, the bottom-up architecture proposed in this paper is more suitable for multi-robot navigation since it can better utilize the advantages of different algorithms to deal with different situations. The experiments on real robots have further verified the applicability of the proposed strategy. 相似文献
6.
《Robotics and Autonomous Systems》2007,55(7):572-588
This paper describes an adaptive task assignment method for a team of fully distributed mobile robots with initially identical functionalities in unknown task environments. A hierarchical assignment architecture is established for each individual robot. In the higher hierarchy, we employ a simple self-reinforcement learning model inspired by the behavior of social insects to differentiate the initially identical robots into “specialists” of different task types, resulting in stable and flexible division of labor; on the other hand, in dealing with the cooperation problem of the robots engaged in the same type of task, Ant System algorithm is adopted to organize low-level task assignment. To avoid using a centralized component, a “local blackboard” communication mechanism is utilized for knowledge sharing. The proposed method allows the robot team members to adapt themselves to the unknown dynamic environments, respond flexibly to the environmental perturbations and robustly to the modifications in the team arising from mechanical failure. The effectiveness of the presented method is validated in two different task domains: a cooperative concurrent foraging task and a cooperative collection task. 相似文献
7.
Chia-Ju Wu 《Journal of Intelligent and Robotic Systems》1994,11(3):209-221
A sensor-based fuzzy algorithm is proposed to navigate a mobile robot in a 2-dimensional unknown environment filled with stationary polygonal obstacles. When the robot is at the starting point, vertices of the obstacles that are visible from the robot are scanned by the sensors and the one with the highest priority is chosen. Here, priority is an output fuzzy variable whose value is determined by fuzzy rules. The robot is then navigated from the starting point to the chosen vertex along the line segment connecting these two points. Taking the chosen vertex as the new starting point, the next navigation decision is made. The navigation process will be repeated until the goal point is reached.In implementation of fuzzy rules, the ranges of fuzzy variables are parameters to be determined. In order to evaluate the effect of different range parameters on the navigation algorithm, the total traveling distance of the robot is defined as the performance index first. Then a learning mechanism, which is similar to the simulated annealing method in the neural network theory, is presented to find the optimal range parameters which minimize the performance index. Several simulation examples are included for illustration. 相似文献
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9.
In this paper, the problem concerning how to coordinate the contributions from concurrent controllers, when controlling mobile robots, is investigated. It is shown how a behavior based control system for autonomous robots can be modeled as a hybrid automaton, where each node corresponds to a distinct robot behavior. This type of construction gives rise to chattering executions, but it is shown how regularized automata can be used to solve this problem. As an illustration, the obstacle-negotiation problem is solved by using a combination of a robust path-following behavior and a reactive obstacle-avoidance behavior that move the robot around a given obstacle at a predefined safety distance. 相似文献
10.
A new technique for enhancing global path planning for mobile robots working in partially known as indoor environments is presented in this paper. The method is based on a graph approach that adapts the cost of the paths by incorporating travelling time from real experiences. The approach uses periodical measurements of time and position reached by the robot while moving to the goal to modify the costs of the branches. Consequently, the search of a feasible path from a static global map in dynamic environments is more realistic than employing a distance metric. Our approach has been tested in simulation as well on an autonomous robot. Results from both simulation and real experiences are discussed. 相似文献
11.
An approach to mobile software robots for the WWW 总被引:1,自引:0,他引:1
Kato K. Someya Y. Matsubara K. Toumura K. Abe H. 《Knowledge and Data Engineering, IEEE Transactions on》1999,11(4):526-548
This paper describes a framework for developing mobile software robots by using the PLANET mobile object system, which is characterized by a language-neutral layered architecture, the native code execution of mobile objects, and asynchronous object passing. We propose an approach to implementing mobile Web search robots that takes full advantage of these characteristics, and we base our discussion of its effectiveness on experiments conducted in the Internet environment. The results show that the PLANET approach to mobile Web search robots significantly reduces the amount of data transferred via the Internet and that it enables the robots to work more efficiently than the robots in the conventional stationary scheme whenever nontrivial amounts of HTML files are processed 相似文献
12.
Altan Onat 《Advanced Robotics》2013,27(14):913-928
This paper presents an approach for the trajectory tracking control of nonholonomic wheeled mobile robots (WMR) by combining one of the existing adaptive control methods and multiple identification models. The overall system includes two types of controllers in the control scheme. A kinematic controller developed by using kinematic model produces the required linear and angular velocities of the robot for tracking a reference trajectory. These required velocities are used to calculate the torques using an adaptive dynamic controller with multiple models. The proposed method uses the multiple models of the WMR for the identification of the dynamic parameters and performs switching between the given models. The models used in the identification are identical, except for the initial estimates of the parameters. By using an adaptive dynamic controller with multiple models of the WMR, enhancement in transient response is obtained. Stability analysis of the overall system is given, and simulation results are presented to demonstrate the effective performance of the adaptive control by using multiple models approach. 相似文献
13.
Mobile manipulation capabilities are key to many new applications of robotics in space, underwater, construction, and service environments. This article discusses the ongoing effort at Stanford University for the development of multiple mobile manipulation systems and presents the basic models and methodologies for their analysis and control. This work builds on four methodologies we have previously developed for fixed-base manipulation: the Operational Space Formulation for task-oriented robot motion and force control; the Dextrous Dynamic Coordination of Macro/Mini structures for increased mechanical bandwidth of robot systems; the Augmented Object Model for the manipulation of objects in a robot system with multiple arms; and the Virtual Linkage Model for the characterization and control of internal forces in a multi-arm system. We present the extension of these methodologies to mobile manipulation systems and propose a new decentralized control structure for cooperative tasks. The article also discusses experimental results obtained with two holonomic mobile manipulation platforms we have designed and constructed at Stanford University. © 1996 John Wiley & Sons, Inc. 相似文献
14.
Lixia Liu Jinwei Yu Jinchen Ji Zhonghua Miao 《International journal of systems science》2013,44(8):1556-1567
This paper addresses the cooperative adaptive consensus tracking for a group of multiple nonholonomic mobile robots, where the nonholonomic robot model is assumed to be a canonical vehicle having two actuated wheels and one passive wheel. By integrating a kinematic controller and a torque controller for the nonholonomic robotic system, a cooperative adaptive consensus tracking strategy is developed for the uncertain dynamic models using Lyapunov-like analysis in combination with backstepping approach and sliding mode technique. A key feature of the developed adaptive consensus tracking algorithm is the introduction of a directed network topology into the control constraints based on algebraic graph theory to characterise the communication interaction among robots, which plays an important role in realising the cooperative consensus tracking with respect to a specific common reference trajectory. Furthermore, a novel framework is proposed for developing a unified methodology for the convergence analysis of the closed-loop control systems, which can fully ensure the desired adaptive consensus tracking for multiple nonholonomic mobile robots. Subsequently, illustrative examples and numerical simulations are provided to demonstrate and visualise the theoretical results. 相似文献
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16.
J. A. Alvarez Bermejo M. A. Lodroman J. A. Lopez-Ramos 《The Journal of supercomputing》2014,70(2):709-720
In this paper we use the Diffie–Hellman key exchange protocol to introduce a decentralized key agreement protocol based on elliptic curves. We do not use any public key infrastructure, which makes it suitable for light devices with low computational and storage capabilities. Thus mobile devices can directly authorize other mobile devices to exchange keys in order to get access to a service or system, in a secure and efficient manner. 相似文献
17.
Behrokh Khoshnevis Professor George Bekey Professor 《Computers & Industrial Engineering》1998,35(3-4):503-506
We discuss the development ideas and merits of a single centralized station to provide supervision, sensing, control, intelligence and perhaps power to a colony of robots, organized for the performance of specific tasks. The consequence of such an approach is that each robot can be much simpler, smaller and less expensive, since no on-board sensing, control and intelligence are required. The issues to be studied concern tradeoffs in control (bandwidth, accuracy, channel capacity); relations between numbers of controllable robots and task suitability and representation for control. 相似文献
18.
A new motion-generation approach is proposed for wheeled mobile robots described by the unicycle kinematic model. This approach permits the generation of smooth continuous-acceleration controls using a dynamic path-inversion procedure that exploits the concept of G/sup 3/ -paths, i.e., Cartesian paths with third-order geometric continuity (both the curvature function and its derivative, with respect to the arc length, are continuous). The exposed steering method is well suited to be adopted for the robot's iterative steering within a supervisory control architecture for sensor-based autonomous navigation. A worked example illustrates the approach. 相似文献
19.
Robust motion control is fundamental to autonomous mobile robots. In the past few years, reinforcement learning (RL) has attracted considerable attention in the feedback control of wheeled mobile robot. However, it is still difficult for RL to solve problems with large or continuous state spaces, which is common in robotics. To improve the generalization ability of RL, this paper presents a novel hierarchical RL approach for optimal path tracking of wheeled mobile robots. In the proposed approach, a graph Laplacian-based hierarchical approximate policy iteration (GHAPI) algorithm is developed, in which the basis functions are constructed automatically using the graph Laplacian operator. In GHAPI, the state space of an Markov decision process is divided into several subspaces and approximate policy iteration is carried out on each subspace. Then, a near-optimal path-tracking control strategy can be obtained by GHAPI combined with proportional-derivative (PD) control. The performance of the proposed approach is evaluated by using a P3-AT wheeled mobile robot. It is demonstrated that the GHAPI-based PD control can obtain better near-optimal control policies than previous approaches. 相似文献
20.
P. K. C. Wang 《野外机器人技术杂志》1991,8(2):177-195
The problem of deriving navigation strategies for a fleet of autonomous mobile robots moving in formation is considered. Here each robot is represented by a particle with a spherical effective spatial domain and a specified cone of visibility. The global motion of each robot in the world space is described by the equations of motion of the robot's center of mass. First, methods for formation generation are discussed. Then, simple navigation strategies for robots moving in formation are derived. A sufficient condition for the stability of a desired formation pattern for a fleet of robots each equipped with the navigation strategy based on nearest neighbor tracking is developed. The dynamic behavior of robot fleets consisting of three or more robots moving in formation in a plane is studied by means of computer simulation. 相似文献