The T-function of a parametric curve

2021 ◽  
pp. 1-29
Author(s):  
Sonia Pérez-Díaz
Keyword(s):  
Parametric Curve

Synergistic real-time compensation of tracking and contouring errors for precise parametric curved contour following systems

2017 ◽  
Vol 232 (19) ◽  
pp. 3367-3383 ◽  
Author(s):  
De-Ning Song ◽  
Jian-Wei Ma ◽  
Zhen-Yuan Jia ◽  
Feng-Ze Qin ◽  
Xiao-Xuan Zhao
Keyword(s):  
Real Time ◽  
High Precision ◽  
Tracking Error ◽  
Estimation Algorithm ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
System Structure ◽  
Parametric Curve ◽  
Contouring Error ◽  
Contour Following

The tracking and contouring errors are inevitable in real computer numerical control contour following because of the reasons such as servo delay and dynamics mismatch. In order to improve the motion accuracy, this paper proposes a synergistic real-time compensation method of tracking and contouring errors for precise parametric curve following of the computer numerical control systems. The tracking error for each individual axis is first compensated, by using the feed-drive models with the consideration of model uncertainties, to enhance the tracking performances of all axes. Further, the contouring error is estimated and compensated to improve the contour accuracy directly, where a high-precision contouring-error estimation algorithm, based on spatial circular approximation of the desired contour neighboring the actual motion position, is presented. Considering that the system structure is coupled after compensation, the stability of the coupled system is analyzed for design of the synergistic compensator. Innovative contributions of this study are that not only the contouring-error can be estimated with a high precision in real time, but also the tracking and contouring performances can be simultaneously improved although there exist modeling errors and disturbances. Simulation and experimental tests demonstrate the effectiveness and advantages of the proposed method.

Computing Equidistant Curves and Surfaces

1993 ◽  
Author(s):  
R. Sarma ◽  
D. Dutta
Keyword(s):  
Fluid Flow ◽  
Mesh Generation ◽  
Flow Analysis ◽  
Parametric Surface ◽  
Engineering Applications ◽  
Parametric Curve ◽  
Curves And Surfaces ◽  
Fluid Flow Analysis

Abstract The problem of computing equidistant curves and surfaces between a point and (i) a parametric curve and (ii) a parametric surface is considered. This problem is important since it can form a basis for further generalizations of the problem, viz., computing equidistant curves and surfaces between a pair of curves and a pair of surfaces. Engineering applications of such equidistant curves and surfaces include fluid flow analysis, mesh generation and shape interrogation.

scholarly journals Chart for Thermoelectric Systems Operation Based on a Ternary Diagram for Bithermal Systems

Entropy ◽  
2018 ◽  
Vol 20 (9) ◽  
pp. 666
Author(s):  
Julien Ramousse ◽  
Christophe Goupil
Keyword(s):  
Heat Pump ◽  
Heat Engine ◽  
Ternary Diagram ◽  
Operating Conditions ◽  
Thermal Dissipation ◽  
Maximum Efficiency ◽  
Joule Effect ◽  
Parametric Curve ◽  
Thermoelectric Systems ◽  
The Impact

Thermoelectric system’s operation needs careful attention to ensure optimal power conversion depending on the application aims. As a ternary diagram of bithermal systems allows a synthetic graphical analysis of the performance attainable by any work-heat conversion system, thermoelectric systems operation is plotted as a parametric curve function of the operating conditions (electric current and reservoirs’ temperature), based on the standard model of Ioffe. The threshold of each operating mode (heat engine, heat pump, thermal dissipation, and forced thermal transfer), along with the optimal efficiencies and powers of the heat pump and heat engine modes, are characterized graphically and analytically as a function of the material properties and the operating conditions. The sensibility of the performance aims (maximum efficiency vs. maximum power) with the operating conditions is, thus, highlighted. In addition, the specific contributions of each phenomenon involved in the semiconductor (reversible Seebeck effect, irreversible heat leakage by conduction and irreversible thermal dissipation by Joule effect) are discussed in terms of entropy generation. Finally, the impact of the exo-irreversibilities on the performance is analyzed by taking the external thermal resistances into account.

On rational parametric curve approximation

1993 ◽  
Vol 10 (3-4) ◽  
pp. 363-377 ◽  
Author(s):  
M.J. Pratt ◽  
R.J. Goult ◽  
L. Ye
Keyword(s):  
Parametric Curve ◽  
Curve Approximation

Simulation and analysis on the ship energy efficiency operational indicator for bulk carriers by Monte Carlo simulation method

2020 ◽  
Vol 11 (04) ◽  
pp. 2050036
Author(s):  
Tien Anh Tran
Keyword(s):  
Energy Efficiency ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Curve Fitting ◽  
Simulation Method ◽  
Monte Carlo Simulation Method ◽  
Bulk Carrier ◽  
Parametric Curve ◽  
Parametric Curve Fitting ◽  
Operational Data

The ship energy efficiency management is an important topic in the field of the energy management onboard and the exhaust gases emission nowadays. The advanced model plays a vital role to improve the ship energy efficiency management when considering the variable factors. The establishment of the ship energy efficiency model through energy efficiency operational indicator (EEOI) index has been conducted through Monte Carlo simulation method along with using the operation data of a bulk carrier. A bulk carrier is chosen, namely, M/V NSU JUSTICE 250,000 DWT of VINIC Shipping Transportation Company in Vietnam. This research uses the real operational data to perform a statistical methodology which calculates the various factors used to calculate EEOI. This method is supported by Matlab program through the curve fitting tool. The normal distribution estimation and the kernel density estimation method are used for the parametric curve fitting and non-parametric curve fitting, respectively. The average weather condition (wind speed and wave height) and the fouling condition of hull have been investigated and compared with the research results. The validation of the proposed methods has been conducted through the study of the external factors influencing the research results. The research result shows the optimal operational data for the fuel consumption at each certain voyage. This paper is useful for the ship-owners and the ship-operators in the field of the ship energy efficiency management.

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