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Reconfigurable Parallel Kinematic Manipulator for Flexible Manufacturing

IFAC Proceedings Volumes 2009年第4期42卷 145-150页

作者： Mathias Haage Isolde Dressler Anders Robertsson Klas Nilsson Torgny Brogårdh Rolf Johansson Dept. Computer Science LTH Lund University Lund Sweden Dept. Automatic Control LTH Lund University Lund Sweden ABB Robotics SE-72168 Västerås Sweden

Flexible manufacturing puts high demands on industrial automation in terms of affordable and competitive solutions and is of key importance for short-lot production typically found in small and medium sized enterprises, situations where today manual labour is extensively used despite e.g. , environmental issues and harsh working conditions. Key factors in the successful introduction of new robot automation concepts are that they provide both the desired performance and quality (technical capability), but also that they enable fast deployment and extend available task repertoire. The Gantry-Tau manipulator is a new robot concept which in contrast to other high-performance parallel kinematic manipulators (PKM), has a large, open working range. Its high stiffness makes it ideal for a wide range of tasks such as grinding, deburring, and cutting. An additional aspect of such a PKM is the modularity, which in this work has been studied in terms of possibilities for assembly and mechanical reconfiguration at the end-user site, integration of such a kinematically different robot with a standard industrial controller, and new needs for methods/tools to support simple (re)configuration. A range of software tools and methods were found to be useful and necessary for efficient engineering and integration of the concept in typical SME manufacturing scenarios. For experimental evaluation, two full-scale prototype robots were designed and built, the kinematic software was developed and integrated into a couple of different robot control systems, robot CAD software was adapted to the configuration needs, and both simulations and physical experiments were carried out. Our findings make us believe that enhanced software tools should be integrated on a higher symbolic (or meta-) level to better support transformation of data and code generation, but also that the Gantry-Tau type of robot (with adequate software support) will bring a new dimension of flexibility into SME manufacturing.

关键词： parallel kinematic robots modularity kinematics force control calibration

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The design and application of DWT-domain optimum decoders

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1st International Workshop on Digital Watermarking, IWDW 2002

作者： Hu, Yongjian Kwong, Sam Chan, Y.K. Dept. of Computer Science City University of Hong Kong Kowloon Hong Kong Dept. of Automatic Control Engg South China University of Tech Guangzhou510641 China School of Info. Sci. and Tech Sun Yat-Sen University Guangzhou510275 China

ISBN: (纸本)3540012176

Based on Bayes theory of hypothesis testing, a new DWTdomain decoder structure for image watermarking has been proposed in this work. The statistical distribution of wavelet coefficients is deliberately described with the Laplacian model so that the decoding algorithm could couple effectiveness and simplicity. Under the Neyman-Pearson criterion, the decision rule is optimized by minimizing the probability of missing the watermark for a given false detection rate. Compared with other domain decoders, the proposed DWT-domain decoder has more flexibility in constructing new watermarking algorithms by using visual models that have varying spatial support. © Springer-Verlag Berlin Heidelberg 2003.

关键词： Decoding

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Prediction in iterative learning control schemes versus learning along the trials 15th

Prediction in iterative learning control schemes versus lear...

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15th World Congress of the International Federation of automatic control, 2002

作者： Rzewuski, M. Rogers, E. Owens, D.H. Dept. of Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom Department of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom

ISBN: (纸本)9783902661746

Recent years has seen much progress in the theory and application of iterative learning control schemes for both linear and (classes of) nonlinear dynamics. In the case of the former, many algorithms based on minimizing a suitable cost function have been reported. Here the interest is in the so-called norm optimal approach where the basic philosophy is to compute the control input on the current trial such that the tracking error is reduced in an optimal way without too much deviation from the control input used on the previous trial. This paper compares the performance of a range of controllers arising from use of the norm optimal approach - both stand alone and against alternatives. Copyright © 2002 IFAC.

关键词： Iterative methods

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Trust Region Policy Optimization with Optimal Transport Discrepancies: Duality and Algorithm for Continuous Actions

arXiv

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arXiv 2022年

作者： Terpin, Antonio Lanzetti, Nicolas Yardim, Batuhan Dörfler, Florian Ramponi, Giorgia Automatic Control Laboratory ETH Zürich Switzerland Dept. of Computer Science ETH Zürich Switzerland Dept. of Computer Science ETH AI Center Switzerland

Policy Optimization (PO) algorithms have been proven particularly suited to handle the high-dimensionality of real-world continuous control tasks. In this context, Trust Region Policy Optimization methods represent a popular approach to stabilize the policy updates. These usually rely on the Kullback-Leibler (KL) divergence to limit the change in the policy. The Wasserstein distance represents a natural alternative, in place of the KL divergence, to define trust regions or to regularize the objective function. However, state-of-the-art works either resort to its approximations or do not provide an algorithm for continuous state-action spaces, reducing the applicability of the method. In this paper, we explore optimal transport discrepancies (which include the Wasserstein distance) to define trust regions, and we propose a novel algorithm – Optimal Transport Trust Region Policy Optimization (OT-TRPO) – for continuous state-action spaces. We circumvent the infinite-dimensional optimization problem for PO by providing a one-dimensional dual reformulation for which strong duality holds. We then analytically derive the optimal policy update given the solution of the dual problem. This way, we bypass the computation of optimal transport costs and of optimal transport maps, which we implicitly characterize by solving the dual formulation. Finally, we provide an experimental evaluation of our approach across various control tasks. Our results show that optimal transport discrepancies can offer an advantage over state-of-the-art approaches. Copyright © 2022, The Authors. All rights reserved.

关键词： Approximation algorithms

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An adaptive dynamic inversion-extremum seeking control approach for constrained robotic motion tasks

An adaptive dynamic inversion-extremum seeking control appro...

引用

European control Conference

作者： Vasiliki Koropouli Azwirman Gusrialdi Dongheui Lee Automatic Control Engineering Technische Universitat Munchen Dept. of Electrical Engineering and Computer Science University of Central Florida

ISBN: (纸本)9781467371605

In this paper, an adaptive control approach is proposed for performance of constrained robot end-effector movements in presence of uncertainty. In real-world scenarios, complex physical phenomena occuring at the place of interaction may introduce nonlinearities in the system dynamics, which have to be taken into account for proper system control. We currently propose an Extremum Seeking (ES) Model Reference Adaptive control (MRAC) approach for state tracking of multiple-input multiple-output systems which enclose nonlinearities in their dynamics and involve parametric uncertainty by employing Adaptive Dynamic Inversion (ADI). According to ADI, system nonlinearities are assumed known and are taken into account in the design of the system control law. The proposed scheme is based on MRAC and ADI while the unknown controller parameters are adapted by ES control. The system is shown to achieve global and asymptotic reference state tracking under the proposed control law by performing Lyapunov and averaging analysis. The approach is evaluated in simulation and in an experimental robot task.

关键词： MIMO Adaptation models Robots Tracking Dynamics Adaptive control Nonlinear dynamical systems

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Kalman filtering of distributed time series

arXiv

引用

arXiv 2017年

作者： Stefanoiu, Dan Culita, Janetta "Politehnica" University of Bucharest Dept. of Automatic Control and Computer Science 313 Splaiul Independentei Bucharest060032 Romania

This paper aims to introduce an application to Kalman Filtering Theory, which is rather unconventional. Recent experiments have shown that many natural phenomena, especially from ecology or meteorology, could be monitored and predicted more accurately when accounting their evolution over some geographical area. Thus, the signals they provide are gathered together into a collection of distributed time series. Despite the common sense, such time series are more or less correlated each other. Instead of processing each time series independently, their collection can constitute the set of measurable states provided by some open system. Modeling and predicting the system states can take benefit from the family of Kalman filtering algorithms. The article describes an adaptation of basic Kalman filter to the context of distributed signals collections and completes with an application coming from Meteorology. Copyright © 2017, The Authors. All rights reserved.

关键词： Kalman filters

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Robust fault detection using interval models

Robust fault detection using interval models

引用

European control Conference (ECC)

作者： S. Tornil T. Escobet L. Travé-Massuyès Automatic Control Dept. Technical University of Catalonia Terrassa Spain Laborarory for Analysis and Architecture of Systems Toulouse Cedex 4 France

The problem of model-based fault detection in the presence of both parametric uncertainty and noise is addressed in this paper. Intervals are used to represent the uncertainty in the system parameters and interval extensions of parity equations are used as adaptive threshold selectors. A proper combination in time of different (interval) parity equations, together with a robust indicator, is used to maintain a good sensitivity to faults whilst avoiding the effect of noise. The results in the application to the detection of different faults in a DC motor are used to show the good properties of the proposed method.

关键词： Mathematical model Robustness Noise Fault detection Uncertainty Adaptation models Wrapping

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Tuning the feedback controller gains is a simple way to improve autonomous driving performance

arXiv

引用

arXiv 2024年

作者： Liang, Wenyu Baldivieso, Pablo R. Drummond, Ross Shin, Donghwan Dept. of Automatic Control and Systems Engineering University of Sheffield Sheffield United Kingdom Dept. of Computer Science University of Sheffield Sheffield United Kingdom

Typical autonomous driving systems are a combination of machine learning algorithms (often involving neural networks) and classical feedback controllers. Whilst significant progress has been made in recent years on the neural network side of these systems, only limited progress has been made on the feedback controller side. Often, the feedback control gains are simply passed from paper to paper with little re-tuning taking place, even though the changes to the neural networks can alter the vehicle’s closed loop dynamics. The aim of this paper is to highlight the limitations of this approach;it is shown that retuning the feedback controller can be a simple way to improve autonomous driving performance. To demonstrate this, the PID gains of the longitudinal controller in the TCP autonomous vehicle algorithm are tuned. This causes the driving score in CARLA to increase from 73.21 to 77.38, with the results averaged over 16 driving scenarios. Moreover, it was observed that the performance benefits were most apparent during challenging driving scenarios, such as during rain or night time, as the tuned controller led to a more assertive driving style. These results demonstrate the value of developing both the neural network and feedback control policies of autonomous driving systems simultaneously, as this can be a simple and methodical way to improve autonomous driving system performance and robustness. © 2024, CC BY.

关键词： Feedback control

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Stochastic circulatory lymphocyte models

Lecture Notes in Control and Information Sciences

引用

Lecture Notes in control and Information Sciences 2006年 106卷 130-145页

作者： Farooqi, Z.H. Mohler, R.R. Dept. of Electrical and Computer Engineering Oregon State University Corvallis OR 97331 United States Institute of Automatic Control Technical University of Warsaw Poland

No abstract available

ISBN: (纸本)9783540188612

No abstract available

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Image Processing Techniques in Vision-Based Robot Navigation

Image Processing Techniques in Vision-Based Robot Navigation

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International Conference on control, Artificial Intelligence, Robotics & Optimization (ICCAIRO)

作者： Rodrigo Munguia Yolanda Bolea Antoni Grau Dept. of Computer Science CUCEI University of Guadalajara Guadalajara México Automatic Control Dept. Technical University of Catalonia UPC Barcelona Spain

ISBN: (纸本)9781538695777;9781538695760

Motivated by the problems of vision-based mobile robot map building and localization, we present a comparative study of statistical methods for matching image features in a wide base line between learning and recognition phases. A general methodology called feature-class method for the problem of fast matching image features in a wide base line is described in the context of mobile robots. The objective of this work is to discuss and to show the performance of such methods in an example of visual SLAM, with experiments done with real data.

关键词： Robots Image processing Navigation Principal component analysis Conferences Artificial intelligence Optimization

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