scholarly journals Dynamic Modelling and Identification of a Waterjet Cutting System

2003 ◽  
Author(s):  
Brian C. Fabien ◽  
M. Ramulu
Keyword(s):  
Dynamic Model ◽  
High Pressures ◽  
Dynamic Modelling ◽  
Check Valve ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Unknown Parameters ◽  
Actual System ◽  
Waterjet Cutting ◽  
Cutting System

This paper describes a new dynamic model for a waterjet cutting system that includes a double-acting reciprocating intensifier pump. Since the system operates at high pressures the fluid flow is assumed to be compressible. The dynamic model includes the characteristics of the intensifier pump, the check valves, the accumulator, the system piping and compressible jet flow through the nozzle. The system model is presented as a set of differential-algebraic equations. Experimental results for an actual system are used to identify the discharge coefficient of the nozzle, certain unknown parameters associated with the check valve, and to determine the velocity profile of the piston in the intensifier pump. The identification is accomplished by formulating and solving a parameter optimization problem. The paper also includes numerical simulation results that validate the dynamic model.

Dynamic Modeling and Grasp Characteristics Analysis of an Underactuated Prosthetic Finger

2014 ◽  
Vol 513-517 ◽  
pp. 3446-3452 ◽  
Author(s):  
Li Chu ◽  
Yi Zhang ◽  
Hua Deng
Keyword(s):  
Dynamic Model ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Constraint Force ◽  
Characteristic Index ◽  
Grasp Stability ◽  
Adaptive Capability ◽  
Prosthetic Finger ◽  
Underactuated Finger ◽  
Self Adaptive

A dynamic model was established using the virtual spring approach for the underactuated prosthetic finger containing the closed kinematic chains and holonomic constraints. The dynamic model was verified by grasp simulation. The virtual spring is used to approximate the constraint force and differential algebraic equations are converted into ordinary differential equations which are ideal for simulation and real-time control. The grasp characteristics of the underactuated finger were studied based on the model with the stiffness of the linear springs as variables. By properly increasing the stiffness of springs, the grasp stability of underactuated finger could be improved and ejection phenomenon would be reduced. However, self-adaptive capability would be reduced with large stiffness. A characteristic index was used for estimating grasp stability and self-adaptive capability. The simulation results show that setting the stiffness of the linear springs between 1N/mm and 2N/mm is the best choice for the underactuated finger.

The Practical Stability Analysis of a Type of Electricity Market Model

2013 ◽  
Vol 278-280 ◽  
pp. 2160-2162 ◽  
Author(s):  
Zhan Hui Lu ◽  
Xin Wu
Keyword(s):  
Stability Analysis ◽  
Dynamic Model ◽  
Electricity Markets ◽  
Electricity Market ◽  
Differential Algebraic Equations ◽  
Market Model ◽  
Practical Stability ◽  
Algebraic Equations

The theory of practical stability is used to study the electricity market model which has the three supplier and two consumers. Based on the dynamic model of electricity market proposed by Alvarado, uses differential-algebraic equations and eigenvalue techniques from the theoretical to study the practical stability of the electricity markets.

scholarly journals A Dynamic Optimization Strategy for the Operation of Large Scale Seawater Reverses Osmosis System

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Aipeng Jiang ◽  
Jian Wang ◽  
Wen Cheng ◽  
Changxin Xing ◽  
Shu Jiangzhou
Keyword(s):  
Finite Element ◽  
Dynamic Model ◽  
Large Scale ◽  
Optimal Solution ◽  
Differential Algebraic Equations ◽  
Optimal Operation ◽  
Algebraic Equations ◽  
Optimization Strategy ◽  
Storage Tanks

In this work, an efficient strategy was proposed for efficient solution of the dynamic model of SWRO system. Since the dynamic model is formulated by a set of differential-algebraic equations, simultaneous strategies based on collocations on finite element were used to transform the DAOP into large scale nonlinear programming problem named Opt2. Then, simulation of RO process and storage tanks was carried element by element and step by step with fixed control variables. All the obtained values of these variables then were used as the initial value for the optimal solution of SWRO system. Finally, in order to accelerate the computing efficiency and at the same time to keep enough accuracy for the solution of Opt2, a simple but efficient finite element refinement rule was used to reduce the scale of Opt2. The proposed strategy was applied to a large scale SWRO system with 8 RO plants and 4 storage tanks as case study. Computing result shows that the proposed strategy is quite effective for optimal operation of the large scale SWRO system; the optimal problem can be successfully solved within decades of iterations and several minutes when load and other operating parameters fluctuate.

UNDERACTUATED HAND DYNAMIC MODELING, ITS REAL-TIME SIMULATION, AND CONTROL

2010 ◽  
Vol 07 (04) ◽  
pp. 609-634 ◽  
Author(s):  
HAI HUANG ◽  
YONG-JIE PANG ◽  
JIANG LI ◽  
SHAO-WEI FAN ◽  
XIN-QING WANG ◽  
...  
Keyword(s):  
Real Time ◽  
Dynamic Model ◽  
Dynamic Models ◽  
Impedance Control ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Inverse Dynamic ◽  
Time Dynamic ◽  
Simulation And Control ◽  
And Control

The forward and inverse dynamic models of the underactuated 2-DOF finger have been established in this article based on virtual spring approach. This approach not only avoids the solution of differential-algebraic equations but also leads to a completely decoupled dynamic model that is ideal for directly inverse dynamic analysis, real-time dynamic simulation and control. To verify this approach, an underactuated 3-joint finger has been brought forward. Simulation results from Matlab/Simulink are consistent with those obtained from ADAMS grasp simulations. For the hand real-time dynamic control, the velocity observer has been established based on the dynamic model, the adaptive curve fitting with the observer has obtained precise velocity signals, made up the uncertain parameters such as torsion spring, inertial, damps, etc. and achieved ideal results. By applying dynamics model and observer, the force-based impedance control can realize more accurate and stable force control during grasp.

Markov Jump Linear System Analysis of a Microgrid Operating in Islanded and Grid Tied Modes

2020 ◽  
Author(s):  
Gilles Mpembele ◽  
Jonathan Kimball
Keyword(s):  
Monte Carlo ◽  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Markov Jump ◽  
Numerical Application ◽  
Conditional Moments ◽  
Markov Jump Linear Systems

<div>The analysis of power system dynamics is usually conducted using traditional models based on the standard nonlinear differential algebraic equations (DAEs). In general, solutions to these equations can be obtained using numerical methods such as the Monte Carlo simulations. The use of methods based on the Stochastic Hybrid System (SHS) framework for power systems subject to stochastic behavior is relatively new. These methods have been successfully applied to power systems subjected to</div><div>stochastic inputs. This study discusses a class of SHSs referred to as Markov Jump Linear Systems (MJLSs), in which the entire dynamic system is jumping between distinct operating points, with different local small-signal dynamics. The numerical application is based on the analysis of the IEEE 37-bus power system switching between grid-tied and standalone operating modes. The Ordinary Differential Equations (ODEs) representing the evolution of the conditional moments are derived and a matrix representation of the system is developed. Results are compared to the averaged Monte Carlo simulation. The MJLS approach was found to have a key advantage of being far less computational expensive.</div>

scholarly journals Differential-algebraic systems are generically controllable and stabilizable

2021 ◽  
Author(s):  
Achim Ilchmann ◽  
Jonas Kirchhoff
Keyword(s):  
Algebraic Geometry ◽  
Linear Time ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Algebraic Systems ◽  
Linear Time Invariant ◽  
Survey Article ◽  
Link Type ◽  
Invariant Differential ◽  
Time Invariant

AbstractWe investigate genericity of various controllability and stabilizability concepts of linear, time-invariant differential-algebraic systems. Based on well-known algebraic characterizations of these concepts (see the survey article by Berger and Reis (in: Ilchmann A, Reis T (eds) Surveys in differential-algebraic equations I, Differential-Algebraic Equations Forum, Springer, Berlin, pp 1–61. 10.1007/978-3-642-34928-7_1)), we use tools from algebraic geometry to characterize genericity of controllability and stabilizability in terms of matrix formats.

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