Approximate Optimal Trajectories for Flexible-Link Manipulator Slewing Using Recursive Quadratic Programming

1993 ◽  
Vol 115 (3) ◽  
pp. 405-410 ◽  
Author(s):  
G. R. Eisler ◽  
R. D. Robinett ◽  
D. J. Segalman ◽  
J. D. Feddema
Keyword(s):  
Quadratic Programming ◽  
Horizontal Plane ◽  
Tracking Error ◽  
Flexible Manipulator ◽  
Joint System ◽  
Recursive Quadratic Programming ◽  
Straight Line ◽  
Tip Position ◽  
The Impact ◽  
Structural Mode

The method of recursive quadratic programming, coupled with a homotopy method, has been used to generate approximate minimum-time and minimum tracking-error tip trajectories for two-link flexible manipulator movements in the horizontal plane. The manipulator is modeled with an efficient finite-element scheme for a multi-link, multi-joint system with bending only in the horizontal-plane. Constraints on the trajectory include boundary conditions on link tip position, final joint velocities, accelerations and torque inputs to complete a rest-to-rest maneuver, straight-line tip tracking between boundary positions, and motor torque limits. Trajectory comparisons demonstrate the impact of torque input smoothness on structural mode excitation. Applied torques retain much of the qualitative character of rigid-body slewing motion with alterations for energy dissipation.

Optimization With Discrete Variables Via Recursive Quadratic Programming: Part 2—Algorithm and Results

1989 ◽  
Vol 111 (1) ◽  
pp. 130-136 ◽  
Author(s):  
J. Z. Cha ◽  
R. W. Mayne
Keyword(s):  
Quadratic Programming ◽  
Performance Comparison ◽  
Programming Algorithm ◽  
Discrete Variables ◽  
Contour Analysis ◽  
Recursive Quadratic Programming ◽  
Analysis Technique ◽  
Rank One ◽  
Symmetric Rank One ◽  
Monotonicity Analysis

A discrete recursive quadratic programming algorithm is developed for a class of mixed discrete constrained nonlinear programming (MDCNP) problems. The symmetric rank one (SR1) Hessian update formula is used to generate second order information. Also, strategies, such as the watchdog technique (WT), the monotonicity analysis technique (MA), the contour analysis technique (CA), and the restoration of feasibility have been considered. Heuristic aspects of handling discrete variables are treated via the concepts and convergence discussions of Part I. This paper summarizes the details of the algorithm and its implementation. Test results for 25 different problems are presented to allow evaluation of the approach and provide a basis for performance comparison. The results show that the suggested method is a promising one, efficient and robust for the MDCNP problem.

scholarly journals Rebalancing of exchange traded funds in stock market using option trading strategies

2021 ◽  
Vol 20 (3) ◽  
pp. 513-527
Author(s):  
Vinaykumar Elegeti
Keyword(s):  
Stock Market ◽  
Stock Markets ◽  
Tracking Error ◽  
Threshold Value ◽  
Trading Strategies ◽  
Exchange Traded Funds ◽  
Dynamic Features ◽  
Financial Industry ◽  
Option Trading ◽  
The Impact

Motivation: The finance and academic industries are highly discussed in the stock market trading domain. The increase in economic globalization shows the connection among stock markets in different countries, which produces the effect of risk conduction in the market. Forecasting the direction of every day’s stock market return is important and challenging. The growing complexity and dynamic features in stock markets are difficult in the financial industry. The inflexible trading method developed by financial practitioners utilized a larger amount of stock market features and is failed to achieve a satisfactory result in every condition of the market. Further, the existing data mining approaches are incomplete and inefficient. Aim: To overcome the issues in stock and problem of existing methods, proposed option trading strategies for rebalancing Exchange Traded Fund (ETF) in the stock market. Rebalancing-ETF measure the volatility of the stock to track the error of model and rebalance the threshold quality to improve the trade. The proposed method increases the order of threshold quantity to rebalance the trade. Results: The result showed that the minimum orders increases in rebalancing trade, which reduces the impact of price formations in market. The tracking error occurs when the larger quantity of threshold value reduces the quantity. Then, the markets are changed significantly when the Net Asset Values (NAV) of rebalancing ETF increases.

The Different Impacts on the Long-Term Survival of Tunneled Internal Jugular Hemodialysis Catheters Based on Tip Position and Laterality

2017 ◽  
Vol 43 (4) ◽  
pp. 315-320 ◽  
Author(s):  
Vedran Premuzic ◽  
Drazen Perkov ◽  
Ranko Smiljanic ◽  
Bruna Brunetta Gavranic ◽  
Bojan Jelakovic
Keyword(s):  
Superior Vena ◽  
Vena Cava ◽  
The Body ◽  
Term Survival ◽  
Catheter Tip ◽  
Tip Position ◽  
The Impact

Background/Aims: The aim of this study was to examine the impact of different catheter tip positions on the life of the catheter, dysfunction, infection, and quality of hemodialysis and possible differences between the access site laterality in jugular-tunneled hemodialysis catheters. Methods: Catheters were evaluated for the following parameters: place of insertion, time of insertion, duration of use, and reason for removal. In all patients, the catheter tip position was checked using an X-ray. Results: The mean duration of implanted catheters with the tip placed in the cavo-atrial junction and right atrium was significantly longer. There were no differences in catheter functionality at follow-up or complications based on catheter laterality for each catheter tip position. Conclusion: According to our results, the localization of the catheter tip in superior vena cava still remains the least preferable method. Our results showed that the main factor responsible for better catheter functionality was not laterality but the depth to which the catheter tip is inserted into the body.

On Viscoelastic Compliant Contact-Impact Models

2004 ◽  
Vol 71 (1) ◽  
pp. 134-138 ◽  
Author(s):  
T. M. Atanackovic ◽  
D. T. Spasic
Keyword(s):  
Deformable Body ◽  
Viscoelastic Body ◽  
Rigid Wall ◽  
Straight Line ◽  
The Laplace Transform ◽  
Contact Impact ◽  
The Impact ◽  
Derivatives Of ◽  
Impact Models ◽  
Straight Rod

We study dynamics of a mass, moving on a straight line, and impacting against the rigid wall through a deformable body, that we model as a straight rod of negligible mass. The chosen constitutive model of the viscoelastic body comprises fractional derivatives of stress and strain and the restrictions on the coefficients that follow from Clausius Duhem inequality. We show that the dynamics of the problem is governed by a single differential equation of real order. The obtained equation was solved numerically. The comparison is made to the solution obtained by the Laplace transform and Post’s inversion formula. The predictions of the model concerning the duration of the impact, maximal values of the impacting force and deformation as well as the restitution coefficient are determined for several values of system parameters.

Towards rational use of baffle arrays on sloped and horizontal terrain for filtering boulders

2020 ◽  
Author(s):  
George Robert Goodwin ◽  
Clarence E. Choi ◽  
Chan-Young Yune
Keyword(s):  
Horizontal Plane ◽  
Impact Load ◽  
Granular Flows ◽  
Rigid Barrier ◽  
Optimum Configuration ◽  
Granular Assembly ◽  
Sloping Terrain ◽  
The Impact ◽  
Current Guidelines ◽  
Array Of Baffles

Baffle arrays are used to filter boulders from granular flows, such that the impact load exerted on barriers is reduced. However, current guidelines provide limited recommendations on baffle design. In this study, a calibrated Discrete Element Method modelled boulders entrained in a bulk granular assembly interacting with baffles and a terminal rigid barrier. Different baffle spacings relative to the boulder diameter (1 < s/δ < 4) were considered. A ratio of s/δ=1 is recommended for reducing the impact load by up to 80%, whilst s/δ = 4 renders an array of baffles inadequate for filtration. The optimum configuration is a staggered array with three rows of baffles on a horizontal plane in front of a barrier. This layout reduces the peak discharge by up to four times more than a similar array on sloping terrain, compared to channels without baffles. Furthermore, the transition from sloping terrain to a horizontal plane works together with the array of baffles to dissipate flow kinetic energy. On the horizontal plane, baffles attenuate the flow velocity more as the Froude number Fr increases, implying that baffles should be used if high Fr are anticipated. Finally, guidance is provided on estimating load attenuation from boulder filtration.

Inertial Surveying Systems — Experience and Prognosis

1980 ◽  
Vol 34 (1) ◽  
pp. 41-53 ◽  
Author(s):  
K. P. Schwarz
Keyword(s):  
Gravity Field ◽  
Error Propagation ◽  
State Of The Art ◽  
Simulation Software ◽  
Propagation Process ◽  
Straight Line ◽  
Imperfect Knowledge ◽  
Quantitative Manner ◽  
Anomalous Gravity ◽  
The Impact

Initially, the principle of inertial positioning is introduced and extensive new data from the Ottawa test net are used to discuss the state of the art. Two major problems presently limit the accuracy of the systems used in production work: heading sensitivity and the imperfect knowledge of the anomalous gravity field. An initial analysis of the new data indicates that the first is a software problem rather than a hardware problem. It appears that positioning of points along an L-shaped traverse can be done with the same accuracy as along a straight line. The second problem is assessed in a quantitative manner using simulation software. The impact of future hardware improvements on the accuracy of positioning is studied by simulating the error propagation process.

scholarly journals Separate motor memories are formed when controlling different implicitly specified locations on a tool

2019 ◽  
Vol 121 (4) ◽  
pp. 1342-1351 ◽  
Author(s):  
Keaton Proud ◽  
James B. Heald ◽  
James N. Ingram ◽  
Jason P. Gallivan ◽  
Daniel M. Wolpert ◽  
...  
Keyword(s):  
Horizontal Plane ◽  
Applied Force ◽  
Control Points ◽  
Contextual Cues ◽  
Task Context ◽  
Object A ◽  
Task Goal ◽  
Straight Line ◽  
Left And Right ◽  
Straight Ahead

Skillful manipulation requires forming and recalling memories of the dynamics of objects linking applied force to motion. It has been assumed that such memories are associated with entire objects. However, we often control different locations on an object, and these locations may be associated with different dynamics. We have previously demonstrated that multiple memories can be formed when participants are explicitly instructed to control different visual points marked on an object. A key question is whether this novel finding generalizes to more natural situations in which control points are implicitly defined by the task. To answer this question, we used objects with no explicit control points and tasks designed to encourage the use of distinct implicit control points. Participants moved a handle, attached to a robotic interface, to control the position of a rectangular object (“eraser”) in the horizontal plane. Participants were required to move the eraser straight ahead to wipe away a column of dots (“dust”), located to either the left or right. We found that participants adapted to opposing dynamics when linked to the left and right dust locations, even though the movements required for these two contexts were the same. Control conditions showed this learning could not be accounted for by contextual cues or the fact that the task goal required moving in a straight line. These results suggest that people naturally control different locations on manipulated objects depending on the task context and that doing so affords the formation of separate motor memories. NEW & NOTEWORTHY Skilled manipulation requires forming motor memories of object dynamics, which have been assumed to be associated with entire objects. However, we recently demonstrated that people can form multiple memories when explicitly instructed to control different visual points on an object. In this article we show that this novel finding generalizes to more natural situations in which control points are implicitly defined by the task.

scholarly journals KiwiSaver fund performance and asset allocation policy

2019 ◽  
Vol 31 (2) ◽  
pp. 232-257
Author(s):  
Huong Dieu Dang
Keyword(s):  
Asset Allocation ◽  
Tracking Error ◽  
Excess Return ◽  
Superior Performance ◽  
Data Set ◽  
Content Type ◽  
Allocation Policy ◽  
Holding Period ◽  
Management Fees ◽  
The Impact

Purpose This paper aims to examine the performance and benchmark asset allocation policy of 70 KiwiSaver funds catergorised as growth, balanced or conservative over the period October 2007-June 2016. The study focuses on the sources for returns variability across time and returns variation among funds. Design/methodology/approach Each fund is benchmarked against a portfolio of eight indices representing eight invested asset classes. Three measures were used to examine the after-fee benchmark-adjusted performance of each fund: excess return, cumulative abnormal return and holding period returns difference. Tracking error and active share were used to capture manager’s benchmark deviation. Findings On average, funds underperform their respective benchmarks, with the mean quarterly excess return (after management fees) of −0.15 per cent (growth), −0.63 per cent (balanced) and −0.83 per cent (conservative). Benchmark returns variability, on average, explains 43-78 per cent of fund’s across-time returns variability, and this is primarily driven by fund’s exposures to global capital markets. Differences in benchmark policies, on average, account for 18.8-39.3 per cent of among-fund returns variation, while differences in fees and security selection may explain the rest. About 61 per cent of balanced and 47 per cent of Growth funds’ managers make selection bets against their benchmarks. There is no consistent evidence that more actively managed funds deliver higher after-fee risk-adjusted performance. Superior performance is often due to randomness. Originality/value This study makes use of a unique data set gathered directly from KiwiSaver managers and captures the long-term strategic asset allocation target which underlines the investment management process in reality. The study represents the first attempt to examine the impact of benchmark asset allocation policy on KiwiSaver fund’s returns variability across time and returns variation among funds.

scholarly journals Evolutionary computing approaches to optimum design of fuzzy logic controller for a flexible robot system

2013 ◽  
Vol 23 (4) ◽  
pp. 395-412 ◽  
Author(s):  
Bidyadhar Subudhi ◽  
Subhakanta Ranasingh
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Position Control ◽  
Fitness Function ◽  
Flexible Manipulator ◽  
Position Tracking ◽  
Flexible Robot ◽  
Robot System ◽  
Single Link ◽  
Tip Position

Abstract This paper presents the design of a Fuzzy Logic Controller (FLC) whose parameters are optimized by using Genetic Algorithm (GA) and Bacteria Foraging Optimization (BFO) for tip position control of a single link flexible manipulator. The proposed FLC is designed by minimizing the fitness function, which is defined as a function of tip position error, through GA and BFO optimization algorithms achieving perfect tip position tracking of the single link flexible manipulator. Then the tip position responses obtained by using both the above controllers are compared to suggest the best controller for the tip position tracking.

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