scholarly journals Human-in-the-Loop Systems with Inner and Outer Feedback Control Loops: Adaptation, Stability Conditions, and Performance Constraints

2019 ◽  
Author(s):  
Ehsan Arabi ◽  
Tansel Yucelen ◽  
Rifat Sipahi ◽  
Yildiray Yildiz
Keyword(s):  
Feedback Control ◽  
Stability Conditions ◽  
Control Loops ◽  
Performance Constraints ◽  
Human In The Loop ◽  
And Performance

scholarly journals Reliable CPS Design for Unreliable Hardware Platforms

2020 ◽  
pp. 545-563
Author(s):  
Wanli Chang ◽  
Swaminathan Narayanaswamy ◽  
Alma Pröbstl ◽  
Samarjit Chakraborty
Keyword(s):  
Feedback Control ◽  
Controller Design ◽  
The Other ◽  
Aging Effects ◽  
Control Loops ◽  
And Performance ◽  
Domestic Robots ◽  
Hardware Platforms ◽  
Semiconductor Aging ◽  
Over Time

AbstractToday, many battery-operated cyber-physical systems (CPS) ranging from domestic robots, to drones, and electric vehicles are highly software-intensive. The software in such systems involves multiple feedback control loops that implement different functionality. How these control loops are designed is closely related to both the semiconductor aging of the processors on which the software is run and also the aging of the batteries in these systems. For example, sudden acceleration in an electric vehicle can negatively impact the health of the vehicle’s battery. On the other hand, processors age over time and stress, impacting the execution of control algorithms and thus the control performance. With increasing semiconductor scaling, and our increasing reliance on battery-operated devices, these aging effects are of concern for the lifetime of these devices. Traditionally, the design of the control loops focused only on control-theoretic metrics, related to stability and performance (such as peak overshoot or settling time). In this chapter we show that such controller design techniques that are oblivious of the characteristics of the hardware implementation platform dramatically worsen the battery behaviour and violate the safety requirement with processor aging. However, with proper controller design these effects can be mitigated—thereby improving the lifetime of the devices.

Passthrough+

2020 ◽  
Vol 3 (1) ◽  
pp. 1-17
Author(s):  
Gaurav Chaurasia ◽  
Arthur Nieuwoudt ◽  
Alexandru-Eugen Ichim ◽  
Richard Szeliski ◽  
Alexander Sorkine-Hornung
Keyword(s):  
Real Time ◽  
Video Encoding ◽  
View Synthesis ◽  
Performance Constraints ◽  
Trade Offs ◽  
Stereoscopic View ◽  
Target User ◽  
Spatio Temporal ◽  
And Performance ◽  
3D Scene

We present an end-to-end system for real-time environment capture, 3D reconstruction, and stereoscopic view synthesis on a mobile VR headset. Our solution allows the user to use the cameras on their VR headset as their eyes to see and interact with the real world while still wearing their headset, a feature often referred to as Passthrough. The central challenge when building such a system is the choice and implementation of algorithms under the strict compute, power, and performance constraints imposed by the target user experience and mobile platform. A key contribution of this paper is a complete description of a corresponding system that performs temporally stable passthrough rendering at 72 Hz with only 200 mW power consumption on a mobile Snapdragon 835 platform. Our algorithmic contributions for enabling this performance include the computation of a coarse 3D scene proxy on the embedded video encoding hardware, followed by a depth densification and filtering step, and finally stereoscopic texturing and spatio-temporal up-sampling. We provide a detailed discussion and evaluation of the challenges we encountered, as well as algorithm and performance trade-offs in terms of compute and resulting passthrough quality.;AB@The described system is available to users as the Passthrough+ feature on Oculus Quest. We believe that by publishing the underlying system and methods, we provide valuable insights to the community on how to design and implement real-time environment sensing and rendering on heavily resource constrained hardware.

scholarly journals Estimating the optimum size of a tidal array at a multi-inlet system considering environmental and performance constraints

2018 ◽  
Vol 232 ◽  
pp. 292-311 ◽  
Author(s):  
Eduardo González-Gorbeña ◽  
André Pacheco ◽  
Theocharis A. Plomaritis ◽  
Óscar Ferreira ◽  
Cláudia Sequeira
Keyword(s):  
Optimum Size ◽  
Inlet System ◽  
Performance Constraints ◽  
And Performance

Drawing with Performance Prediction

1995 ◽  
Author(s):  
Peter Schwenn ◽  
George Hazen
Keyword(s):  
Design Optimization ◽  
Performance Prediction ◽  
Fold Increase ◽  
Building Blocks ◽  
Programming Environment ◽  
Immediate Feedback ◽  
Surface Stability ◽  
Performance Constraints ◽  
And Performance ◽  
The One

We describe some advances in Performance Prediction Programs - "PPP"1 for sailing yachts2 - primarily integrating PPP analysis into drawing and providing new sculpting operations in which fairness and desired hydrostatic and on her performance determining characteristics are maintained - the shape remains a boat or a ship of the desired kind during reshaping. Our building blocks for such an integration are: a thousand-fold increase in PPP speed3, new editing tools which maintain Boatness4 , and an accessible modularization of the engineering physics of the PPP within a new programming environment which allows immediate changes by designers. Specifically, these new functions are introduced at the boundary of Drawing and the PPP: - A live knotmeter is displayed with each design variant on the drawing boar, - alongside it's antagonist - Rating. - Continuously updated hydrotatics (including the speed determining factors LSM, wetted surface, stability, prismatics, .. ) are displayed with the knotometer, with the 'positive' factors (like length) graphically opposing the 'negative' (like wetted surface.) Dimensions for PPP use are calculated automatically from the shape at hand - in particular: appendage dimensions, hydrostatics, and so forth. - Bounding limits are set for a design optimization by drawing two or more outlier yacht forms. The space in between can be explored by hand or automatically. - Local optimums of Speed against rating are provided as a 'Snap' function. This is the one dimensional version of automatic exploration for optima. - Intermediate shapes are also controlled during design optimization to maintain realism and performance constraints on type, fairness, 'look', speed producing shape measures like prismatic and displacement etc., and even handicap. - Immediate feedback is available if one chooses to exploit the new programming environment to make aero hydro model changes or extensions to the internal PPP mechanisms while drawing and exploring.

Dynamic Analysis and Stability Improvement Concerning the Integration of Wind Farms Kurdistan Electric Network Case Study

2011 ◽  
pp. 198-219 ◽  
Author(s):  
Mohammad Saleh ◽  
Hassan Bevrani
Keyword(s):  
Wind Power ◽  
Dynamic Models ◽  
Wind Farms ◽  
Integrated System ◽  
Electric Network ◽  
Control Approach ◽  
Control Loops ◽  
And Performance ◽  
The Stability

This chapter presents an overview of key issues and technical challenges in a regional electric network, following the integration of a considerable amount of wind power. A brief survey on wind power system, the present status of wind energy worldwide, common dynamic models, and control loops for wind turbines are given. In this chapter, the Kurdistan electric network in the Northwest part of Iran is introduced as a case study system, and an analytical approach is conducted to evaluate the potential of wind power installation, overall capacity estimation, and economic issues, based on the practical data. Then, the impact of high penetration wind power on the system dynamic and performance for various wind turbine technologies is presented. The stability of integrated system is analyzed, and the need for revising of conventional controls and performance standards is emphasized. Finally, a STATCOM-based control approach is addressed to improve the system stability.

Towards a Conceptual Design Explorer Using Metamodeling Approaches and Constraint Programming

2003 ◽  
Author(s):  
Bernard Yannou ◽  
Timothy W. Simpson ◽  
Russell R. Barton
Keyword(s):  
Conceptual Design ◽  
Constraint Programming ◽  
Degrees Of Freedom ◽  
Practical Interest ◽  
Preference Aggregation ◽  
Surface Model ◽  
Performance Variables ◽  
Performance Constraints ◽  
And Performance ◽  
Mechanical Performances

Constraint Programming (CP) is a promising technique for managing uncertainty in conceptual design. It provides efficient algorithms for reducing, as quickly as possible, the domains of the design and performance variables while complying to the engineering and performance constraints linking them. In addition, CP techniques are suitable to graphically represent 3D projections of the complete design space. This is a useful capability for a better understanding of the product concept’s degrees of freedom and a valuable alternative to optimization based upon the construction of an arbitrary preference aggregation function. Unfortunately, one of the main impediments for using Constraint Programming on industrial problems of practical interest is that constraints must be represented by analytical equations, which is not the case of hard mechanical performances — such as meshing and finite element computations — that are usually obtained after lengthy simulations. We propose to use metamodeling techniques (MM) to generate approximated mathematical models of these analyses which can be employed directly within a CP environment, expanding the scope of CP to applications that previously could not be solved by CP due to the unavailability of analytical equations. We show that there is a tradeoff between the metamodel fidelity and the resulting CP constraint tractability. A strategy to find this compromise is presented. The case study of a combustion chamber design shows amazingly that the compromise is to favor the simplest and the coarsest first-order response surface model.

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