A New Approach for Electrical Drives Controllers Tuning Based on Optimal Closed-Loop Bandwidth Detection

2019 ◽  
Author(s):  
Aurelian Sarca
Keyword(s):  
Closed Loop ◽  
New Approach ◽  
Electrical Drives ◽  
Loop Bandwidth

scholarly journals Decision making in reverse logistics using system dynamics

2004 ◽  
Vol 14 (2) ◽  
pp. 259-272 ◽  
Author(s):  
P. Georgiadis ◽  
D. Vlachos
Keyword(s):  
Decision Making ◽  
System Dynamics ◽  
Reverse Logistics ◽  
Closed Loop ◽  
System Modeling ◽  
New Approach ◽  
Helpful Tool ◽  
Starting Point ◽  
Decision Making Tool

Reverse logistics is a modern field of consideration, research and study, providing helpful information on the operation of the closed-loop supply chain. Although the starting point of this field is traced back to the early 90?s, no standard method has been suggested, neither prevailed. The purpose of this paper is to introduce a new approach on the study of reverse logistics. It is actually a review on how System Dynamics (SD) can be a helpful tool when it is used in the reverse logistics field. The paper explains the basic theory of the system modeling and next it utilizes the reverse logistics model. Finally, an illustrative example shows how SD modeling can be used to produce a powerful long-term decision-making tool.

Sliding Mode Output Feedback Control of Vibration in a Flexible Structure

2007 ◽  
Vol 129 (6) ◽  
pp. 851-855 ◽  
Author(s):  
M. C. Pai ◽  
A. Sinha
Keyword(s):  
Output Feedback ◽  
Control Algorithm ◽  
Closed Loop ◽  
Sliding Mode ◽  
Output Feedback Control ◽  
Flexible Structure ◽  
Numerical Verification ◽  
Closed Loop System ◽  
New Approach ◽  
Small Gain

This paper presents a new approach for the robust control of vibration in a flexible structure in the presence of uncertain parameters and residual modes. The technique is based on the sliding mode control algorithm using direct output feedback and assumes that actuators and sensors are not collocated. The uncertainty matrix need not satisfy the invariance or matching conditions. The small gain theorem/μ analysis is applied to analyze the asymptotic behavior of the closed-loop system with parametric uncertainties inside boundary layers. The model of a flexible tetrahedral truss structure is used to conduct numerical verification of the theoretical analysis.

Dynamic Modeling and Simulation of Parallel Mechanisms Using the Virtual Spring Approach

2000 ◽  
Author(s):  
Jiegao Wang ◽  
Clément M. Gosselin ◽  
Li Cheng
Keyword(s):  
Closed Loop ◽  
Differential Algebraic Equations ◽  
Parallel Mechanisms ◽  
Algebraic Equations ◽  
New Approach ◽  
Flexible Links ◽  
Simulation Results ◽  
Loop Constraints ◽  
Virtual Springs ◽  
Good Agreement

Abstract A new approach for the dynamic simulation of parallel mechanisms or mechanical systems is presented in this paper. This approach uses virtual springs and dampers to include the closed-loop constraints thereby avoiding the solution of differential-algebraic equations. Examples illustrating the approach are given and include the four-bar mechanism with both rigid and flexible links as well as the 6-dof Gough-Stewart platform. Simulation results are given for the four-bar linkages and the 6-dof manipulator. The results achieve a good agreement with the results obtained from other conventional approaches.

Characterization and Attenuation of Sandwiched Deadband Problem Using Describing Function Analysis and Its Application to Electro-Hydraulic Systems Controlled by Closed-Center Valves

2004 ◽  
Author(s):  
Song Liu ◽  
Bin Yao
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Function Analysis ◽  
Nonlinear Behavior ◽  
Hydraulic Systems ◽  
Describing Function ◽  
Widespread Application ◽  
Actuator Dynamics ◽  
Loop Bandwidth ◽  
Highly Nonlinear

Sandwiched deadbands can be seen in a wide variety of systems, such as electro-hydraulic systems controlled by closed-center valves. In such a system, the deadband is between the plant and actuator dynamics and therefore can not be compensated directly like an input deadband. Though this sandwiched deadband problem may be attenuated to certain degree through sophisticated advanced control techniques, the increased cost and the necessity of actuator state feedback prohibit their widespread application in the industry. An economical and popular method is to add an inverse deadband function in the controller to cancel or compensate the highly nonlinear behavior of the deadband. However, such a solution requires that the dynamics before the deadband (eg. the valve dynamics) is fast enough to be neglected — a requirement that can not be met in reality unless the closed loop bandwidth of the overall system is limited very low. To raise the achievable closed loop bandwidth for a much improved control performance, it is essential to be able to precisely characterize the effect of this sandwiched deadband on the stability and performance of the overall closed-loop system, which is the main focus of the paper. Specifically, a describing function based nonlinear analysis will be conducted to predict when the instability will occur and how the resulting limit cycle depends on the actuator dynamics and the targeted closed-loop bandwidth. Based on the analysis, the optimal closed-loop bandwidth can be determined to maximize the achievable overall system performance. The technique is applied to an electro-hydraulic system controlled by closed-center valves to optimize the controller design.

scholarly journals Research of the Robust Stability of Control Systems Using a New Approach to the Lyapunov Functions Construction

2015 ◽  
Vol 9 (11) ◽  
pp. 176 ◽  
Author(s):  
Gulzhan Uskenbayeva
Keyword(s):  
Robust Stability ◽  
Lyapunov Functions ◽  
Closed Loop ◽  
Time Derivative ◽  
State Equation ◽  
The State ◽  
New Approach ◽  
Vector Lyapunov Functions ◽  
The Matrix ◽  
The Right

<p class="22">We investigate a new approach to the construction of vector Lyapunov functions. An approach to the construction of Lyapunov functions as vector functions is developed based on a geometrical interpretation of the second method of Lyapunov. The negative of the gradient is determined from the components of the time derivative of the state vector (i.e., the right-hand side of the state equation). The region of stability of a closed-loop linear, stationary system with uncertain parameters is governed by inequalities in the matrix elements of the closed-loop system. This study developed a method for analysing the robust stability of SISO and MIMO linear systems in canonical forms.</p>

Study of Dominant Performance Characteristics in Robot Transmissions

1993 ◽  
Vol 115 (3) ◽  
pp. 472-482 ◽  
Author(s):  
H. Schempf ◽  
D. R. Yoerger
Keyword(s):  
Force Control ◽  
Closed Loop ◽  
Stability Margin ◽  
Viscous Friction ◽  
Open Loop ◽  
Phase Lag ◽  
Stability Margins ◽  
Loop Bandwidth ◽  
Hard Contact ◽  
Following Error

Six different transmission types suitable for robotic manipulators were compared in an experimental and theoretical study. Single-degree-of-freedom mechanisms based on the different transmissions were evaluated in terms of force control performance, achievable bandwidth, and stability properties in hard contact tasks. Transmission types considered were (1) cable reducer, (2) harmonic drive, (3) cycloidal disk reducer, (4) cycloidal cam reducer, (5) ball reducer, and (6) planetary/cycloidal gear head. Open loop torque following error, attenuation and phase lag, and closed loop bandwidth and stability margin were found to be severely dominated by levels of inertia, stiffness distribution and variability, stiction, coulomb and viscous friction, and ripple torque. These aspects were quantified and shown to vary widely among all transmissions tested. The degree of nonlinearity inherent in each transmission affected its open and closed loop behavior directly, and limited the effectiveness of controller compensation schemes. Simple transmission models based on carefully measured transmission characteristics are shown to predict stability margins and achievable force-control bandwidths in hard contact to within a 5 to 15 percent error margin.

Design of a High-Bandwidth XY Nanopositioning Stage for High-Throughput Micro/Nano Manufacturing

2010 ◽  
Author(s):  
Sebastian Polit ◽  
Jingyan Dong
Keyword(s):  
Mechanism Design ◽  
High Throughput ◽  
Closed Loop ◽  
Open Loop ◽  
Dynamic Responses ◽  
Element Analysis ◽  
Loop Bandwidth ◽  
Decoupled Motion ◽  
High Bandwidth ◽  
Critical Requirement

A high natural frequency (open-loop bandwidth) is a critical requirement for nanopositioners in high-throughput nanomanufacturing and nano-metrology applications. This paper presents the design and analysis of a high-bandwidth nanopositioning XY stage. The monolithic stage design has two axes and each axis is comprised of a doubly-clamped beam and a parallelogram hybrid flexure with complaint beams and circular flexure hinges. The doubly-clamped beam that is actuated by a piezoelectric actuator acts as a linear prismatic axis. The parallelogram hybrid flexures are used to decouple the actuation effect from the other axis. The mechanism design decouples the motion in the X and Y directions and restricts parasitic rotations in the XY plane while allowing for an increased bandwidth with linear kinematics in the operating region (or workspace). Kinematic and dynamic analysis shows that the mechanical structure of the stage has decoupled motion in XY direction, while achieving high bandwidth and good linearity. Finite element analysis is adapted to verify the dynamic responses from theoretical analysis. The stage is actuated by piezoelectric stack actuators, and two capacitive gauges were added to the system to build a closed-loop positioning system. The results from frequency test show that the resonation frequencies of the two vibrational modes are over 8K Hz. The stage is capable of about 15 microns of motion along each axis with a resolution of about 1 nanometer. Due to parallel kinematic mechanism design, a uniform performance is achieved across the workspace. A PI controller is implemented for the stage and a high closed-loop bandwidth is obtained.

scholarly journals Research on Spillover Effects for Vibration Control of Piezoelectric Smart Structures by ANSYS

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xingjian Dong ◽  
Zhike Peng ◽  
Wenming Zhang ◽  
HongXing Hua ◽  
Guang Meng
Keyword(s):  
Finite Element ◽  
Closed Loop ◽  
Parametric Design ◽  
Smart Structures ◽  
Element Model ◽  
Spillover Effects ◽  
Smart Structure ◽  
Control Laws ◽  
Actual Structure ◽  
New Approach

To control vibration of a piezoelectric smart structure, a controller is usually designed based on a reduced order model (ROM) of the system. When such a ROM based controller operates in closed loop with the actual structure, spillover phenomenon occurs because the unmodeled dynamics, which are not included in ROM, will be excited. In this paper, a new approach aiming at investigating spillover effects in ANSYS software is presented. By using the ANSYS parametric design language (APDL), the ROM based controller is integrated into finite element model to provide an accurate representation of what will happen when the controller is connected to the real plant. Therefore, the issues of spillover effects can be addressed in the closed loop simulation. Numerical examples are presented for investigating spillover effects of a cantilever piezoelectric plate subjected to various types of loading. The importance of considering spillover effects in closed loop simulation of piezoelectric smart structures is demonstrated. Moreover, the present study may provide an efficient method especially beneficial for preliminary design of piezoelectric smart structure to evaluate the performance of candidate control laws in finite element environment considering spillover effects.

scholarly journals Fundamental Limits in Combine Harvester Header Height Control

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yangmin Xie ◽  
Andrew G. Alleyne ◽  
Ashley Greer ◽  
Dustin Deneault
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
The Other ◽  
Specific System ◽  
Fundamental Limits ◽  
Height Control ◽  
Sensor Actuator ◽  
Loop Transfer Function ◽  
Loop Bandwidth ◽  
Combine Harvester

This paper investigates fundamental performance limitations in the control of a combine harvester's header height control system. There are two primary subsystem characteristics that influence the achievable bandwidth by affecting the open loop transfer function. The first subsystem is the mechanical configuration of the combine and header while the second subsystem is the electrohydraulic actuation for the header. The mechanical combine + header subsystem results in an input–output representation that is underactuated and has a noncollocated sensor/actuator pair. The electrohydraulic subsystem introduces a significant time delay. In combination, they each reinforce the effect of the other thereby exacerbating the overall system limitation of the closed loop bandwidth. Experimental results are provided to validate the model and existence of the closed loop bandwidth limitations that stem from specific system design configurations.

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