Experiments on Point-to-Point Control of a Flexible Beam Using Laplace Transform Technique: Part II—Closed-Loop

1991 ◽  
Vol 113 (3) ◽  
pp. 438-443 ◽  
Author(s):  
S. P. Bhat ◽  
D. K. Miu
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Open Loop ◽  
Flexible Beam ◽  
Laplace Domain ◽  
Loop Control ◽  
Feed Forward Control ◽  
Laplace Transform Technique ◽  
Point Control ◽  
Point To Point

Using the Laplace domain synthesis technique documented in earlier publications, experiments on the closed-loop point-to-point position control of a flexible beam are presented. Two different approaches are described, a feed-forward control and an iterative open-loop control. Solution to the robustness problems encountered during actual implementation is also demonstrated.

Experiments on Point-to-Point Position Control of a Flexible Beam Using Laplace Transform Technique: Part I—Open-Loop

1991 ◽  
Vol 113 (3) ◽  
pp. 432-437 ◽  
Author(s):  
S. P. Bhat ◽  
M. Tanaka ◽  
D. K. Miu
Keyword(s):  
Position Control ◽  
Flexible Structures ◽  
Open Loop ◽  
Engineering Problem ◽  
Flexible Beam ◽  
Loop Control ◽  
Point Position ◽  
Control Functions ◽  
Laplace Transform Technique ◽  
Point To Point

When lightly damped flexible structures are used in high bandwidth applications, the elimination of residual vibration during point-to-point positioning is an important engineering problem. Using the Laplace domain synthesis technique introduced in earlier publications, experiments on the precise point-to-point position control of a flexible beam have been performed. In Part I of this two-part paper, results related to open-loop control are presented. A variety of candidate control functions are evaluated and performance issues related to robustness and sensitivity are investigated.

Design and Modelling of a Novel Servovalve Actuated by a Piezoelectric Ring Bender

2015 ◽  
Author(s):  
L. Johan Persson ◽  
Andrew R. Plummer ◽  
Christopher R. Bowen ◽  
Ian Brooks
Keyword(s):  
Mathematical Model ◽  
Closed Loop ◽  
Position Control ◽  
Open Loop ◽  
Closed Loop Control ◽  
Hydraulic Fluid ◽  
Loop Control ◽  
Frequency Responses ◽  
Spool Valve ◽  
The Mathematical Model

This paper describes the design, simulation and testing of a piezoelectric spool valve. An actuator has been connected to the valve and tested under closed loop control. A mathematical model of the valve was produced and a prototype of the valve was tested. The mathematical model is validated against the experimental data. Step and frequency responses for both the valve and actuator are presented. It was found that displacement of the hydraulic fluid by the ring bender had an impact on the valve performance. To reduce the effect of the piezoelectric hysteresis, closed loop spool position control was evaluated. A noticeable difference can be observed between open loop and closed loop performance.

Solutions to Point-to-Point Control Problems Using Laplace Transform Technique

1991 ◽  
Vol 113 (3) ◽  
pp. 425-431 ◽  
Author(s):  
S. P. Bhat ◽  
D. K. Miu
Keyword(s):  
Laplace Transform ◽  
Linear Time ◽  
Open Loop ◽  
Control Problems ◽  
Algebraic Equations ◽  
Programming Technique ◽  
Linear Algebraic Equations ◽  
Laplace Transform Technique ◽  
Point Control ◽  
Point To Point

Using finite-time Laplace transform, the governing differential equations of linear, time invariant point-to-point control problems are converted into an equivalent set of linear algebraic equations embedded with the desired boundary conditions, characterizing the entire set of optimal and sub-optimal solutions. A linear programming technique for synthesizing the control inputs using selected sets of basis functions is presented. A new concept of feedback control which involves a recursive evaluation of the open-loop input is also developed.

Experimental Study of Laser Interferometry Based Motion Tracking of a Flexure-Based Mechanism

2013 ◽  
pp. 165-178
Author(s):  
Umesh Bhagat ◽  
Bijan Shirinzadeh ◽  
Yanling Tian
Keyword(s):  
Experimental Study ◽  
Motion Tracking ◽  
Closed Loop ◽  
Position Control ◽  
Laser Interferometry ◽  
Open Loop ◽  
Closed Loop Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Model Based

This paper presents an experimental study of laser interferometry-based closed-loop motion tracking for flexure-based four-bar micro/nano manipulator. To enhance the accuracy of micro/nano manipulation, laser interferometry-based motion tracking control is established with experimental facility. The authors present and discuss open-loop control, model-based closed-loop control, and robust motion tracking closed-loop control for flexure-based mechanism. A comparative error analysis for closed-loop control with capacitive position sensor and laser interferometry feedback is discussed and presented. Model-based closed-loop control shows improvement in position and motion tracking over open-loop control. Robust control demonstrates high precise and accurate motion tracking of flexure-based mechanism compared to the model-based control. With this experimental study, this paper offers evidence that the laser interferometry-based closed-loop control can minimize positioning and tracking errors during dynamic motion, hence realizing high precision motion tracking and accurate position control.

Experimental Study of Laser Interferometry Based Motion Tracking of a Flexure-Based Mechanism

2011 ◽  
Vol 1 (3) ◽  
pp. 31-45 ◽  
Author(s):  
Bijan Shirinzadeh ◽  
Umesh Bhagat ◽  
Yanling Tian
Keyword(s):  
Experimental Study ◽  
Motion Tracking ◽  
Closed Loop ◽  
Position Control ◽  
Laser Interferometry ◽  
Open Loop ◽  
Closed Loop Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Model Based

This paper presents an experimental study of laser interferometry-based closed-loop motion tracking for flexure-based four-bar micro/nano manipulator. To enhance the accuracy of micro/nano manipulation, laser interferometry-based motion tracking control is established with experimental facility. The authors present and discuss open-loop control, model-based closed-loop control, and robust motion tracking closed-loop control for flexure-based mechanism. A comparative error analysis for closed-loop control with capacitive position sensor and laser interferometry feedback is discussed and presented. Model-based closed-loop control shows improvement in position and motion tracking over open-loop control. Robust control demonstrates high precise and accurate motion tracking of flexure-based mechanism compared to the model-based control. With this experimental study, this paper offers evidence that the laser interferometry-based closed-loop control can minimize positioning and tracking errors during dynamic motion, hence realizing high precision motion tracking and accurate position control.

scholarly journals The Admissible Control Correction Method in a Nonlinear Terminal Perturbed Problem

2021 ◽  
Vol 11 (12) ◽  
pp. 5560
Author(s):  
Yuliya Belinskaya ◽  
Mikhail Dmitriev ◽  
Dmitry Makarov
Keyword(s):  
Admissible Control ◽  
Perturbation Parameter ◽  
Correction Method ◽  
Limit Problem ◽  
Open Loop ◽  
Unperturbed System ◽  
Problem Solution ◽  
Loop Control ◽  
Point Control ◽  
Point To Point

A solution of a nonlinear perturbed unconstrained point-to-point control problem, in which the unperturbed system is differentially flat, is considered in the paper. An admissible open-loop control in it is constructed using the covering method. The main part of the obtained admissible control correction in the limit problem is found by expanding the perturbed problem solution in series by the perturbation parameter. The first term of the expansion is determined by A.N. Tikhonov’s regularization of the Fredholm integral equation of the first kind. As shown by numerical experiments, the found structure of an admissible control allows one to find the final form of high precision point-to-point control based on the solution of an auxiliary variational problem in its neighborhood.

Active Control of Combustion Instability Using Symmetric and Asymmetric Premix Fuel Modulation

2007 ◽  
Author(s):  
Daniel Guyot ◽  
Christian Oliver Paschereit
Keyword(s):  
Heat Release ◽  
Closed Loop ◽  
Modulation Frequency ◽  
Combustion Instability ◽  
Open Loop ◽  
Closed Loop Control ◽  
Nox Emissions ◽  
Loop Control ◽  
Asymmetric Modulation ◽  
Control Schemes

Active instability control was applied to an atmospheric swirl-stabilized premixed combustor using open loop and closed loop control schemes. Actuation was realised by two on-off valves allowing for symmetric and asymmetric modulation of the premix fuel flow while maintaining constant time averaged overall fuel mass flow. Pressure and heat release fluctuations in the combustor as well as NOx, CO and CO2 emissions in the exhaust were recorded. In the open loop circuit the heat release response of the flame was first investigated during stable combustion. For symmetric fuel modulation the dominant frequency in the heat release response was the modulation frequency, while for asymmetric modulation it was its first harmonic. In stable open loop control a reduction of NOx emissions due to fuel modulation of up to 19% was recorded. In the closed loop mode phase-shift control was applied while triggering the valves at the dominant oscillation frequency as well as at its second subharmonic. Both, open and closed loop control schemes were able to successfully control a low-frequency combustion instability, while showing only a small increase in NOx emissions compared to, for example, secondary fuel modulation. Using premixed open loop fuel modulation, attenuation was best when modulating the fuel at frequencies different from the dominant instability frequency and its subharmonic. The performance of asymmetric fuel modulation was generally slightly better than for symmetric modulation in terms of suppression levels as well as emissions. Suppression of the instability’s pressure rms level of up to 15.7 dB was recorded.

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