A Simplified Method for Discrete-Time Repetitive Control Using Model-Less Finite Impulse Response Filter Inversion

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Yik R. Teo ◽  
Andrew J. Fleming ◽  
Arnfinn A. Eielsen ◽  
J. Tommy Gravdahl
Keyword(s):  
Discrete Time ◽  
Best Practice ◽  
Finite Impulse Response ◽  
Repetitive Control ◽  
Periodic Signal ◽  
Signal Model ◽  
Consistent Manner ◽  
Practice Methods ◽  
Impulse Response Filter ◽  
Selection Of

Repetitive control (RC) achieves tracking and rejection of periodic exogenous signals by incorporating a model of a periodic signal in the feedback path. To improve the performance, an inverse plant response filter (IPRF) is used. To improve robustness, the periodic signal model is bandwidth-limited. This limitation is largely dependent on the accuracy of the IPRF. A new method is presented for synthesizing the IPRF for discrete-time RC. The method produces filters in a simpler and more consistent manner than existing best-practice methods available in the literature, as the only variable involved is the selection of a windowing function. It is also more efficient in terms of memory and computational complexity than existing methods. Experimental results for a nanopositioning stage show that the proposed method yields the same or better tracking performance compared to existing methods.

scholarly journals The Structure of Autocovariance Matrix of Discrete Time Subfractional Brownian Motion

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Guo Jiang
Keyword(s):  
Brownian Motion ◽  
Discrete Time ◽  
Approximation Theorem ◽  
Finite Impulse Response ◽  
Structure Theorem ◽  
Stationary Processes ◽  
Time Varying ◽  
Subfractional Brownian Motion ◽  
Autocovariance Matrix ◽  
Impulse Response Filter

This article explores the structure of autocovariance matrix of discrete time subfractional Brownian motion and obtains an approximation theorem and a structure theorem to the autocovariance matrix of this stochastic process. Moreover, we give an expression to the unique time varying eigenvalue of the autocovariance matrix in asymptotic means and prove that the increments of subfractional Brownian motion are asymptotic stationary processes. At last, we illustrate these results with numerical experiments and give some probable applications in finite impulse response filter.

scholarly journals Artistic Freedom or Animal Cruelty? Contemporary Visual Art Practice That Involves Live and Deceased Animals

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 812
Author(s):  
Ellie Coleman ◽  
Rebecca Scollen ◽  
Beata Batorowicz ◽  
David Akenson
Keyword(s):  
Best Practice ◽  
Animal Cruelty ◽  
Art Practice ◽  
Animal Protection ◽  
Ethical Implications ◽  
High Profile ◽  
Unethical Practices ◽  
Artistic Freedom ◽  
Legal Guidelines ◽  
Selection Of

This paper examines a selection of 21st-century international examples of exhibited visual artworks involving live or deceased animals. It seeks to reveal the risks and benefits of unique encounters with animals through art and to consider the ethical implications of artwork deploying animals. Australian and international animal protection laws are not explicit when it comes to the sourcing of animals for art nor for the direct inclusion of animals in artworks. This lack leads to a variety of artistic practices, some considered ethical while others are viewed as controversial, bordering on animal cruelty. Artwork selection is determined by a focus on high-profile artists who intentionally use animals in their practice and whose reputation has been fostered by this intention. The study provides insight into how the intentional use of ethically sourced animals within art practice can be a method of addressing hierarchal human–animal imbalances. Further, this study identifies unethical practices that may be best avoided regardless of the pro-animal political statements the artists put forward. Recommendations of how to better determine what is an acceptable use of animals in art with a view to informing legal guidelines and artistic best practice are presented.

scholarly journals Zero-Width Quasi-Sliding Mode Band in the Presence of Non-Matched Uncertainties

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3011
Author(s):  
Paweł Latosiński ◽  
Andrzej Bartoszewicz
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
Control Strategies ◽  
Relative Degree ◽  
Band Width ◽  
Representative Point ◽  
Mode Control ◽  
Sliding Motion ◽  
Selection Of

Sliding mode control strategies are well known for ensuring robustness of the system with respect to disturbance and model uncertainties. For continuous-time plants, they achieve this property by confining the system state to a particular hyperplane in the state space. Contrary to this, discrete-time sliding mode control (DSMC) strategies only drive the system representative point to a certain vicinity of that hyperplane. In established literature on DSMC, the width of this vicinity has always been strictly greater than zero in the presence of uncertainties. Thus, ideal sliding motion was considered impossible for discrete-time systems. In this paper, a new approach to DSMC design is presented with the aim of driving the system representative point exactly onto the sliding hyperplane even in the presence of uncertainties. As a result, the quasi-sliding mode band width is effectively reduced to zero and ideal discrete-time sliding motion is ensured. This is achieved with the proper selection of the sliding hyperplane, using the unique properties of relative degree two sliding variables. It is further demonstrated that, even in cases where selection of a relative degree two sliding variable is impossible, one can use the proposed technique to significantly reduce the quasi-sliding mode band width.

scholarly journals Consensus for the General Use of Equine Water Treadmills for Healthy Horses

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 305
Author(s):  
Kathryn Nankervis ◽  
Carolyne Tranquille ◽  
Persephone McCrae ◽  
Jessica York ◽  
Morgan Lashley ◽  
...  
Keyword(s):  
Working Group ◽  
Best Practice ◽  
Treadmill Exercise ◽  
Good Practice ◽  
Belt Speed ◽  
Research Programmes ◽  
Potential Benefits ◽  
Water Treadmill ◽  
Selection Of

Water treadmill exercise has become popular in recent years for the training and rehabilitation of equine athletes. In 2019, an equine hydrotherapy working group was formed to establish what was commonly considered to be best practice in the use of the modality. This article describes the process by which general guidelines for the application of water treadmill exercise in training and rehabilitation programmes were produced by the working group. The guidelines describe the consensus reached to date on (1) the potential benefits of water treadmill exercise, (2) general good practice in water treadmill exercise, (3) introduction of horses to the exercise, (4) factors influencing selection of belt speed, water depth and duration of exercise, and (5) monitoring movement on the water treadmill. The long-term goal is to reach a consensus on the optimal use of the modality within a training or rehabilitation programme. Collaboration between clinicians, researchers and experienced users is needed to develop research programmes and further guidelines regarding the most appropriate application of the modality for specific veterinary conditions.

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