This paper is about the interface between continuous and discrete robot control. We advocate encapsulating continuous actions and their related sensing strategies into behaviors called situation specific activities, w...
详细信息
ISBN:
(纸本)0819407488
This paper is about the interface between continuous and discrete robot control. We advocate encapsulating continuous actions and their related sensing strategies into behaviors called situation specific activities, which can be constructed by a symbolic reactive planner. Task- specific, real-time perception is a fundamental part of these activities. While researchers have successfully used primitive touch and sonar sensors in such situations, it is more problematic to achieve reasonable performance with complex signals such as those from a video camera. Active vision routines are suggested as a means of incorporating visual data into real time control and as one mechanism for designating aspects of the world in an indexical-functional manner. Active vision routines are a particularly flexible sensing methodology because different routines extract different functional attributes from the world using the same sensor. In fact, there will often be different active vision routines for extracting the same functional attribute using different processing techniques. This allows an agent substantial leeway to instantiate its activities in different ways under different circumstances using different active vision routines. We demonstrate the utility of this architecture with an object tracking example. A control system is presented that can be reconfigured by a reactive planner to achieve different tasks. We show how this system allows us to build interchangeable tracking activities that use either color histogram or motion based active vision routines.
control of multiple robots has attracted researchers' interests for many years. Problems arise when uncertainty or coordinated motions are involved. This paper investigates several issues related to control of rob...
详细信息
ISBN:
(纸本)0819407488
control of multiple robots has attracted researchers' interests for many years. Problems arise when uncertainty or coordinated motions are involved. This paper investigates several issues related to control of robot systems with multiple arms. We present a systematic control strategy for the coordination of robot motions during homogeneous manipulations. A hybrid force and position control law is used to determine the force and position targets of the object being manipulated. The frictional equilibrium and stability principles are employed in computing the optimal force distribution among the robots. The position targets for the end effector of individual robots are calculated using appropriate transformations which take into account the coordinating constraints. A generalized control algorithm is developed using this strategy and the manipulation can be achieved by specifying a number of external quantities, which describe the nature of the tasks to be performed, as the inputs to the control algorithm. This control strategy is adopted in developing control algorithms for heterogeneous manipulation tasks such as tasks that require robot interchange during the manipulation. In such as task, it is necessary to coordinate the motions between the coordinating robots and a free robot. A hierarchical control mechanism is used in achieving this coordination. The control primitives developed for controlling robots in the homogeneous manipulation can be used in this hierarchical control. The control algorithms have been successfully implemented on a robot system to perform various tasks with good results.
We discuss how explicit knowledge of the characteristic errors of a sensor can be made use of in parametric object recovery. In doing so we present a view of object recovery using minimization of error which separates...
详细信息
ISBN:
(纸本)0819407488
We discuss how explicit knowledge of the characteristic errors of a sensor can be made use of in parametric object recovery. In doing so we present a view of object recovery using minimization of error which separates its tools and techniques into three distinct components: parametric object model, error-of-fit model, and sensor model. This distinction allows for the development of each component in isolation from the others and the clarification of their interactions. The parametric object model serves to represent the target object we wish to recover. In the minimization of error paradigm an initial guess at the target object is postulated. The parametric object model is then adjusted to minimize some measurement of the distance between the it and the datapoints. This measurement is the error-of-fit model. The sensor model makes explicit the contributions of a sensor. It is used to express in a convenient form the confidence we have in the values reported by the sensor. And, allows a certainty measure to be assigned to the conjecture that some given point 'could' have been reported by the sensor. Given this knowledge we can better know what information to incorporate into the error-of-fit model. We present an algorithm for object recovery which exploits sensor models.
A class of image sequences can be characterized as being spatially invariant and linearly additive based on their image formation processes. In these kinds of sequences, all features are positionally invariant in each...
详细信息
ISBN:
(纸本)0819407488
A class of image sequences can be characterized as being spatially invariant and linearly additive based on their image formation processes. In these kinds of sequences, all features are positionally invariant in each image of a given sequence but have varying gray-scale properties. The various features of the scene contribute additively to each image of the sequence but the image-formation processes associated with given features have characteristic signatures describing the manner in which they vary over the image sequence. Examples of appropriate image sequences include multispectral image sequences, certain temporal image sequences, and NMR image sequences generated by modification of the excitation parameters. Note that image sequences can be formed using a variety of imaging modalities as long as the linearly additive and spatially invariant requirements are not violated. Features associated with different image-formation processes generally will have unique signatures that can be used to generate linear filters for isolating selected image-formation processes or for performing data compression. Starting with an explicit mathematical model, techniques are presented for generating optimal filters using simultaneous diagonalization for enhancement of desired image-formation processes and data compression with this class of image sequences. A unique property of this approach is that even if several image-formation processes occupy a given pixel, they can still be isolated.
Shape sensing based on optical fiber-Bragg-grating technology is an important field of research that promises to bring a solution for the observation and tracking of flexible tubes. Currently for shape sensing, an opt...
详细信息
ISBN:
(纸本)9780996452748
Shape sensing based on optical fiber-Bragg-grating technology is an important field of research that promises to bring a solution for the observation and tracking of flexible tubes. Currently for shape sensing, an optical fiber with integrated Bragg-gratings is attached to a flexible material, to measure the material strain caused by bending. In this paper, a new approach for shape sensing is presented. For the first time, the Bragg-grating structures and the optical waveguides are directly inscribed in planar cyclo-olefin copolymers that can perform characteristic deformation itself. This new method solves many present problems in shape sensing. These problems are e.g. that the placement of the fibers along the carrier material is difficult to realize in practice. Also the fiber does not always connect properly to the carrier material. Thus, the material deformation can not be sufficiently applied to the fiber. The general idea of optical shape sensing and the advantages of the new concept are explained in section I and II. Further on, the manufacturing process of a prototype is described in section II-A. To use the presented 1-component sensor for shape sensing, a geometrical model is defined and assumptions regarding the behavior of the measured values are made in section II-B. The prototype is tested and the measurement data is compared to the defined model. The obtained results are shown in section III. Finally, in section iv, a conclusion of the work is given.
Civil and military structures are susceptible and vulnerable to damage due to the environmental and operational conditions. Therefore, the implementation of technology to provide robust solutions in damage identificat...
详细信息
Civil and military structures are susceptible and vulnerable to damage due to the environmental and operational conditions. Therefore, the implementation of technology to provide robust solutions in damage identification (by using signals acquired directly from the structure) is a requirement to reduce operational and maintenance costs. In this sense, the use of sensors permanently attached to the structures has demonstrated a great versatility and benefit since the inspection system can be automated. This automation is carried out with signal processing tasks with the aim of a pattern recognition analysis. This work presents the detailed description of a structural health monitoring (SHM) system based on the use of a piezoelectric (PZT) active system. The SHM system includes: (i) the use of a piezoelectric sensor network to excite the structure and collect the measured dynamic response, in several actuation phases;(ii) data organization;(iii) advanced signal processing techniques to define the feature vectors;and finally;(iv) the nearest neighbor algorithm as a machine learning approach to classify different kinds of damage. A description of the experimental setup, the experimental validation and a discussion of the results from two different structures are included and analyzed.
Shape sensing based on optical fiber-Bragg-grating technology is an important field of research that promises to bring a solution for the observation and tracking of flexible tubes. Currently for shape sensing, an opt...
详细信息
ISBN:
(纸本)9781509020126
Shape sensing based on optical fiber-Bragg-grating technology is an important field of research that promises to bring a solution for the observation and tracking of flexible tubes. Currently for shape sensing, an optical fiber with integrated Bragg-gratings is attached to a flexible material, to measure the material strain caused by bending. In this paper, a new approach for shape sensing is presented. For the first time, the Bragg-grating structures and the optical waveguides are directly inscribed in planar cyclo-olefin copolymers that can perform characteristic deformation itself. This new method solves many present problems in shape sensing. These problems are e.g. that the placement of the fibers along the carrier material is difficult to realize in practice. Also the fiber does not always connect properly to the carrier material. Thus, the material deformation can not be sufficiently applied to the fiber. The general idea of optical shape sensing and the advantages of the new concept are explained in section I and II. Further on, the manufacturing process of a prototype is described in section II-A. To use the presented 1-component sensor for shape sensing, a geometrical model is defined and assumptions regarding the behavior of the measured values are made in section II-B. The prototype is tested and the measurement data is compared to the defined model. The obtained results are shown in section III. Finally, in section iv, a conclusion of the work is given.
暂无评论