This paper presents an analysis of a decentralized coordination strategy for organizing and controlling a team of mobile robots performing collective search. The alpha-beta coordination strategy is a family of collect...
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This paper presents an analysis of a decentralized coordination strategy for organizing and controlling a team of mobile robots performing collective search. The alpha-beta coordination strategy is a family of collective search algorithms that allow teams of communicating robots to implicitly coordinate their search activities through a division of labor based on self-selected roles. In an alpha-beta team, alpha agents are motivated to improve their status by exploring new regions of the search space. Beta agents are conservative, and rely on the alpha agents to provide advanced information on favorable regions of the search space. An agent selects its current role dynamically based on its current status value relative to the current status values of the other team members. Status is determined by some function of the agent's sensor readings, and is generally a measurement of source intensity at the agent's current location. Variations on the decision rules determining alpha and beta behavior produce different versions of the algorithm that lead to different global properties. The alpha-beta strategy is based on a simple finite-state machine that implements a form of Variable Structure control (VSC). The VSC system changes the dynamics of the collective system by abruptly switching at defined states to alternative control laws. In VSC, Lyapunov's direct method is often used to design control surfaces which guide the system to a given goal. We introduce the alpha-beta algorithm and present an analysis of the equilibrium point and the global stability of the alpha-beta algorithm based on Lyapunov's method.
This paper investigates how the psychological notion of comfort can be useful in the design of roboticsystems. A review of the existing study of human comfort, especially regarding its presence in infants, is conduct...
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ISBN:
(纸本)0819438618
This paper investigates how the psychological notion of comfort can be useful in the design of roboticsystems. A review of the existing study of human comfort, especially regarding its presence in infants, is conducted with the goal being to determine the relevant characteristics for mapping it onto the robotics domain. Focus is placed on the identification of the salient features in the environment that affect the comfort level. Factors involved include current state familiarity, working conditions, the amount and location of available resources, etc. As part of our newly developed comfort function theory, the notion of an object as a psychological attachment for a robot is also introduced, as espoused in Bowlby's theory of attachment. The output space of the comfort function and its dependency on the comfort level are analyzed. The results of the derivation of this comfort function are then presented in terms of the impact they have on robotic behavior. Justification for the use of the comfort function in the domain of robotics is presented with relevance for real-world operations. Also, a transformation of the theoretical discussion into a mathematical framework suitable for implementation within a behavior-based control system is presented. The paper concludes with results of simulation studies and real robot experiments using the derived comfort function.
This paper describes the development of advanced rover navigation and manipulation techniques for use by NASA's Sample Return Rover. These techniques include an algorithm for estimating the change in the rover'...
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ISBN:
(纸本)0819429848
This paper describes the development of advanced rover navigation and manipulation techniques for use by NASA's Sample Return Rover. These techniques include an algorithm for estimating the change in the rover's position aid orientation ky registering successive range maps from the rover's hazard avoidance stereo camera pair and the fusion of this information with the rover's wheel odometry. This map registration technique is also extended to register range maps to an a priori model-based range map for relative rover position and orientation determination. Finally, a technique for the robust and precise positioning of a rover-mounted manipulator using visual feedback from the rover's stereo pair is presented. Experimental results for each of these techniques is documented in this paper.
When autonomous systems with multiple agents are considered, conventional control- and supervision technologies are often inadequate because the amount of information available is often presented in a way that the use...
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ISBN:
(纸本)0819429848
When autonomous systems with multiple agents are considered, conventional control- and supervision technologies are often inadequate because the amount of information available is often presented in a way that the user is effectively overwhelmed by the displayed data. New virtual reality (VR) techniques can help to cope with this problem, because VR offers the chance to convey information in a intuitive manner and can combine supervision capabilities and new, intuitive approaches to the control of autonomous systems. In the approach taken, control and supervision issues were equally stressed and finally led to the new ideas and the general framework for Projective Virtual Reality. The key idea of this new approach for an intuitively operable man machine interface for decentrally controlled multi-agent systems is to let the user act in the virtual world, detect the changes and have an action planning component automatically generate task descriptions for the agents involved to project actions that have been carried out by users in the virtual world into the physical world, e.g. with the help of robots. Thus the Projective Virtual Reality approach is to split the job between the task deduction in the VR and the task "projection" onto the physical automation components by the automatic action planning component. Besides describing the realized projective virtual reality system, the paper will also describe in detail the metaphors and visualization aids used to present different types of (e.g. sensor-) information in an intuitively comprehensible manner.
Generally, there are multiple sensor suites on existing rover platforms such as NASA's Sample Return Rover (SRR) and the Field Integrated Design and Operations (FIDO) rover at JPL. Traditionally, these sensor suit...
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ISBN:
(纸本)0819434329
Generally, there are multiple sensor suites on existing rover platforms such as NASA's Sample Return Rover (SRR) and the Field Integrated Design and Operations (FIDO) rover at JPL. Traditionally, these sensor suites have been used in isolation for such tasks as planetary surface traversal. For example, although distant obstacle information is known from the narrow FOV navigation camera (NAVCAM) suite on SRR or FIDO, it is not explicitly used at this time for augmentation of the wide FOV hazard camera (HAZCAM) information for obstacle avoidance. This paper describes the development of advanced rover navigation techniques. These techniques include an algorithm for the generation of range maps using the fusion of information from the NAVCAMs and HAZCAMs, and an algorithm for registering range maps to an a priori model-based range map for relative rover position and orientation determination. Experimental results for each of these techniques are documented in this paper.
A manned Mars habitat will require a significant amount of infrastructure that can be deployed using robotic precursor missions. This infrastructure deployment will probably include the use of multiple, heterogeneous,...
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ISBN:
(纸本)0819438618
A manned Mars habitat will require a significant amount of infrastructure that can be deployed using robotic precursor missions. This infrastructure deployment will probably include the use of multiple, heterogeneous, mobile robotic platforms. Delays due to the long communication path to Mars limit the amount of teleoperation that is possible. A control architecture called CAMPOUT (control Architecture for Multirobot Planetary Outposts) is currently under development at the Jet Propulsion Lab in Pasadena, CA. It is a three layer behavior-based system that incorporates the low level control routines currently used on the JPL SRR/FIDO/LEMUR revers. The middle behavior layer uses either the BISMARC (Biologically Inspired System for Map based Autonomous Rover control) or MOBC (Multi-Objective Behavior control) action selection mechanisms. CAMPOUT includes the necessary group behaviors and communication mechanisms for coordinated/cooperative control of heterogeneous robotic platforms. We report the results of some ongoing work at the Jet Propulsion Lab in Pasadena, CA on the transport phase of a photovoltaic (PV) tent deployment mission.
We report on the development of cooperating multiple robots. This work builds from our earlier research on autonomous planetary revers and robot arms. Here, we seek to closely coordinate the mobility and manipulation ...
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ISBN:
(纸本)0819438618
We report on the development of cooperating multiple robots. This work builds from our earlier research on autonomous planetary revers and robot arms. Here, we seek to closely coordinate the mobility and manipulation of multiple robots to perform site construction operations-as an example, the autonomous deployment of a planetary power station-a task viewed as essential to a sustained robotic presence and human habitation on Mars. There are numerous technical challenges;these include the mobile handling of extended objects, as well as cooperative transport/navigation of such objects over natural, unpredictable terrain. We describe an extensible system concept, related simulations, a hardware implementation, and preliminary experimental results. In support of this work we have developed an enabling hybrid control architecture wherein multi-robot mobility and sensor-based controls are derived as group compositions and coordination of more basic behaviors under a task-level multi-agent planner. We summarize this control Architecture for Multi-robot Planetary Outposts (CAMPOUT), and its application to physical experiments where two revers carry an extended payload over natural terrain.
In this manuscript, we discuss new solutions for mechanical design and motion planning for a class of three-dimensional modular self-reconfigurable robotic system, namely I-Cubes. This system is a bipartite collection...
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ISBN:
(纸本)0819438618
In this manuscript, we discuss new solutions for mechanical design and motion planning for a class of three-dimensional modular self-reconfigurable robotic system, namely I-Cubes. This system is a bipartite collection of active links that provide motions for self-reconfiguration, and cubes acting as connection points. The links are three degree of freedom manipulators that can attach to and detach from the cube faces. The cubes can be positioned and oriented using the links. These capabilities enable the system to change its shape and perform locomotion tasks over difficult terrain. This paper describes the scaled down version of the system previously described in [1] and details the new design and manufacturing approaches. Initially designed algorithms for motion planning of I-Cubes are improved to provide better results. Results of our tests are given and issues related to motion planning are discussed. The user interfaces designed for the control of the system and algorithm evaluation is also described.
We investigate teams of complete autonomous agents that can collaborate towards achieving precise objectives in an adversarial dynamic environment. We have pursued this work in the context of robotic soccer both in si...
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ISBN:
(纸本)0819434329
We investigate teams of complete autonomous agents that can collaborate towards achieving precise objectives in an adversarial dynamic environment. We have pursued this work in the context of robotic soccer both in simulation and with real physical robots. We briefly present these two frameworks emphasizing their different technical challenges. Creating effective members of a team is a challenging research problem. We first address this issue by introducing a team architecture organization which allows for a rich task decomposition between team members. The main contribution of this paper is our introduction of an action-selection algorithm that allows for a teammate to anticipate the needs of other teammates. Anticipation is critical for maximizing the probability of successful collaboration in teams of agents. We show how our contribution applies to the two concrete robotic soccer frameworks and present controlled empirical results run in simulation. Anticipation was successfully used by both our CMUnited-98 simulator and CMUnited-98 small-robot teams in the RoboCup98 competition. The two teams are RoboCup-98 world champions each in its own league.
Emergence of stable gaits in locomotion robots is studied in this paper. A classifier system, implementing an instance-based reinforcement learning scheme, is used for sensory-motor control of an eight-legged mobile r...
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ISBN:
(纸本)0819434329
Emergence of stable gaits in locomotion robots is studied in this paper. A classifier system, implementing an instance-based reinforcement learning scheme, is used for sensory-motor control of an eight-legged mobile robot. Important feature of the classifier system is its ability to work with the continuous sensor space. The robot does not have a priori knowledge of the environment, its own internal model, and the goal coordinates. It is only assumed that the robot can acquire stable gaits by learning how to reach a light source. During the learning process the control system is self-organized by reinforcement signals. Reaching the light source defines a global reward. Forward motion gets a local reward, while stepping back and falling down get a local punishment. Feasibility of the proposed self-organized system is tested under simulation and experiment. The control actions are specified at the leg level. It is shown that, as learning progresses, the number of the action rules in the classifier systems is stabilized to a certain level, corresponding to the acquired gait patterns.
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