High-speed closed-loop dual deformable-mirror phase-diversity testbed

2007 ◽  
Author(s):  
James A. Georges III ◽  
Pam Dorrance ◽  
Kurt Gleichman ◽  
Julie Jonik ◽  
Dean Liskow ◽  
...  
Keyword(s):  
High Speed ◽  
Closed Loop ◽  
Deformable Mirror ◽  
Phase Diversity

scholarly journals Redesigned Sensor Holder for an Atomic Force Microscope with an Adjustable Probe Direction

2021 ◽  
Author(s):  
Janik Schaude ◽  
Maxim Fimushkin ◽  
Tino Hausotte
Keyword(s):  
Atomic Force Microscope ◽  
Piezoelectric Actuator ◽  
High Speed ◽  
Closed Loop ◽  
Coefficient Of Thermal Expansion ◽  
Measuring System ◽  
Contact Mode ◽  
Loop Control ◽  
Atomic Force ◽  
Measuring Machine

AbstractThe article presents a redesigned sensor holder for an atomic force microscope (AFM) with an adjustable probe direction, which is integrated into a nano measuring machine (NMM-1). The AFM, consisting of a commercial piezoresistive cantilever operated in closed-loop intermitted contact-mode, is based on two rotational axes, which enable the adjustment of the probe direction to cover a complete hemisphere. The axes greatly enlarge the metrology frame of the measuring system by materials with a comparatively high coefficient of thermal expansion. The AFM is therefore operated within a thermostating housing with a long-term temperature stability of 17 mK. The sensor holder, connecting the rotational axes and the cantilever, inserted one adhesive bond, a soldered connection and a geometrically undefined clamping into the metrology circle, which might also be a source of measurement error. It has therefore been redesigned to a clamped senor holder, which is presented, evaluated and compared to the previous glued sensor holder within this paper. As will be shown, there are no significant differences between the two sensor holders. This leads to the conclusion, that the three aforementioned connections do not deteriorate the measurement precision, significantly. As only a minor portion of the positioning range of the piezoelectric actuator is needed to stimulate the cantilever near its resonance frequency, a high-speed closed-loop control that keeps the cantilever within its operating range using this piezoelectric actuator further on as actuator was implemented and is presented within this article.

High-Performance Motion Control With Slosh: A Constrained Sliding Mode Approach

2008 ◽  
Author(s):  
Hanz Richter ◽  
Kedar B. Karnik
Keyword(s):  
High Speed ◽  
High Performance ◽  
Design Methodology ◽  
Closed Loop ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Rectilinear Motion ◽  
Industrial Setting ◽  
Open Container ◽  
Nominal Performance

The problem of controlling the rectilinear motion of an open container without exceeding a prescribed liquid level and other constraints is considered using a recently-developed constrained sliding mode control design methodology based on invariant cylinders. A conventional sliding mode regulator is designed first to address nominal performance in the sliding mode. Then an robustly-invariant cylinder is constructed and used to describe the set of safe initial conditions from which the closed-loop controller can be operated without constraint violation. Simulations of a typical transfer illustrate the usefulness of the method in an industrial setting. Experimental results corresponding to a high-speed transfer validate the theory.

Control of a lamination process

2005 ◽  
Vol 219 (1) ◽  
pp. 69-81 ◽  
Author(s):  
R Whalley ◽  
M Ebrahimi
Keyword(s):  
High Speed ◽  
Closed Loop ◽  
Cost Effective ◽  
Closed Loop System ◽  
Design Validation ◽  
Control Effort ◽  
Speed Of Response ◽  
Feedback Compensation ◽  
Lamination Process ◽  
Compensation Design

A high-speed laminating machine for a fabric coating and conversion process is considered. Following analysis procedures, state-space and the admittance transfer function descriptions for the system are derived. Regulation of the fabric tension owing to heat shrinkage and environmental and coating variations is necessary. An optimum, minimum control effort strategy is proposed, enabling simple cost effective regulation, without the use of active elements. The speed of response of the system is improved by the use of feedback compensation. Design validation, via simulation, obtaining the open- and closed-loop system responses is employed, demonstrating the achievement of smooth, almost monotonic variations in tension following reference changes, as specified.

scholarly journals The Modelling, Simulation and FPGA-Based Implementation for Stepper Motor Wide Range Speed Closed-Loop Drive System Design

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 56 ◽  
Author(s):  
Chiu-Keng Lai ◽  
Jhang-Shan Ciou ◽  
Chia-Che Tsai
Keyword(s):  
Embedded System ◽  
High Speed ◽  
Closed Loop ◽  
Open Loop ◽  
Drive System ◽  
Stepper Motor ◽  
Motor Drive ◽  
Digital Controllers ◽  
Loop Control ◽  
Wide Range

Owing to the benefits of programmable and parallel processing of field programmable gate arrays (FPGAs), they have been widely used for the realization of digital controllers and motor drive systems. Furthermore, they can be used to integrate several functions as an embedded system. In this paper, based on Matrix Laboratory (Matlab)/Simulink and the FPGA chip, we design and implement a stepper motor drive. Generally, motion control systems driven by a stepper motor can be in open-loop or closed-loop form, and pulse generators are used to generate a series of pulse commands, according to the desired acceleration/run/deceleration, in order to the drive system to rotate the motor. In this paper, the speed and position are designed in closed-loop control, and a vector control strategy is applied to the obtained rotor angle to regulate the phase current of the stepper motor to achieve the performance of operating it in low, medium, and high speed situations. The results of simulations and practical experiments based on the FPGA implemented control system are given to show the performances for wide range speed control.

scholarly journals High Speed, High Temperature, Fault Tolerant Operation of a Combination Magnetic-Hydrostatic Bearing Rotor Support System for Turbomachinery

2004 ◽  
Author(s):  
Mark Jansen ◽  
Gerald Montague ◽  
Andrew Provenza ◽  
Alan Palazzolo
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Closed Loop ◽  
Fault Tolerant ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Displacement Sensors ◽  
Rotor Support ◽  
Active Vibration ◽  
Speed Computer

Closed loop operation of a single, high temperature magnetic radial bearing to 30,000 RPM (2.25 million DN) and 540°C (1,000°F) is discussed. Also, high temperature, fault tolerant operation for the three axis system is examined. A novel, hydrostatic backup bearing system was employed to attain high speed, high temperature, lubrication free support of the entire rotor system. The hydrostatic bearings were made of a high lubricity material and acted as journal-type backup bearings. New, high temperature displacement sensors were successfully employed to monitor shaft position throughout the entire temperature range and are described in this paper. Control of the system was accomplished through a stand alone, high speed computer controller and it was used to run both the fault-tolerant PID and active vibration control algorithms.

scholarly journals High-Temperature Superconducting Non-Insulation Closed-Loop Coils for Electro-Dynamic Suspension System

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1980
Author(s):  
Li Lu ◽  
Wei Wu ◽  
Xin Yu ◽  
Zhijian Jin
Keyword(s):  
High Temperature ◽  
Liquid Helium ◽  
High Speed ◽  
Closed Loop ◽  
Permanent Magnets ◽  
Superconducting Magnets ◽  
Current Mode ◽  
Persistent Current ◽  
Magnetomotive Force ◽  
High Temperature Superconducting

The null-flux electro-dynamic suspension (EDS) system is a feasible high-speed maglev system with speeds of above 600 km/h. Owing to their greater current-carrying capacity, superconducting magnets can provide a super-magnetomotive force that is required for the null-flux EDS system, which cannot be provided by electromagnets and permanent magnets. Relatively mature high-speed maglev technology currently exists using low-temperature superconducting (LTS) magnets as the core, which works in the liquid helium temperature region (T ⩽ 4.2 K). Second-generation (2G) high-temperature superconducting (HTS) magnets wound by REBa2Cu3O7−δ (REBCO, RE = rare earth) tapes work above the 20 K region and do not rely on liquid helium, which is rare on Earth. In this study, the HTS non-insulation closed-loop coils module was designed for an EDS system and excited with a persistent current switch (PCS). The HTS coils module can work in the persistent current mode and exhibit premier thermal quenching self-protection. In addition, a full-size double-pancake (DP) module was designed and manufactured in this study, and it was tested in a liquid nitrogen (LN2) environment. The critical current of the DP module was approximately 54 A, and it could work in the persistent current mode with an average decay rate measured over 12 h of 0.58%/day.

Modeling and Analysis for Thermal Control of Spindles for Reconfigurable Machines

2001 ◽  
Author(s):  
Jeffrey L. Stein ◽  
John E. Harder
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Thermal Control ◽  
Open Loop ◽  
Limiting Factor ◽  
Process Conditions ◽  
Bearing Load ◽  
Bearing Loads

Abstract Control of thermally induced bearing loads remains an important but unsolved problem for precision, high-speed, metal cutting, machining spindles. Spindle dynamic performance, as well as spindle life, depends on bearing loads. Because these loads can change drastically with a change in process conditions, poor spindle dynamic performance, and dramatically reduced bearing life can result. The purpose of this paper is to evaluate the feasibility of controlling bearing loads by controlling the heat generated by a thermal actuator placed around the housing of the spindle. A mathematical model of the open loop response of a laboratory prototype spindle is developed and validated. The model is then used to evaluate the closed loop performance. The results show that closed loop control of the bearing load is achievable in steady state and under bandwidth limited transient conditions. The proposed system has reasonable command authority when additional heat is required, however, it is possible for the system to lose control when the heater is required to “provide” negative heat. This situation can be mitigated by proper choice of initial preload. As expected, measurement noise limits the control gain but is not a limiting factor. More open loop tests are suggested to validate the model under a broader set of conditions. In addition, closed loop validation is suggested. However, based on results obtained it appears bearing load control is achievable by controlling the thermal field around the spindle.

scholarly journals Extended depth-of-field microscopy with a high-speed deformable mirror

2017 ◽  
Vol 42 (5) ◽  
pp. 995 ◽  
Author(s):  
William J. Shain ◽  
Nicholas A. Vickers ◽  
Bennett B. Goldberg ◽  
Thomas Bifano ◽  
Jerome Mertz
Keyword(s):  
High Speed ◽  
Deformable Mirror ◽  
Depth Of Field ◽  
Extended Depth Of Field

The Design of Monitoring System in Large Hydraulic Press Aiming at the Precise Closed-Loop Control

2014 ◽  
Vol 989-994 ◽  
pp. 3062-3069
Author(s):  
Heng Du ◽  
Bin Huang ◽  
Lin Wang ◽  
Shu Mei Chen
Keyword(s):  
Data Acquisition ◽  
Monitoring System ◽  
High Speed ◽  
Closed Loop ◽  
Hydraulic Press ◽  
Signal Acquisition ◽  
Closed Loop Control ◽  
Repeated Testing ◽  
Loop Control ◽  
The Status

In the research and development of the precise closed-loop control system in large hydraulic press, the touch screen and PLC are frequently applied to design, debug and test for the system. Though a better closed-loop control characteristic can be acquired after repeated testing by this way, the comprehensive state data of hydraulic press are unable to get, which leads to a long research cycle and also restricts the maintenance and upgrade with the equipment in the later period. In order to obtain the whole state information of hydraulic press easily and effectively, a monitor system of precise closed-loop control in large hydraulic press is designed. Based on reasonable cooperation of sensors and high-speed data-acquisition card, high-speed and precise signal acquisition is realized. In addition, data-acquisition software program is designed base on LabVIEW, it can achieve the functions of collecting, storing, displaying and analyzing data. Through the real measuring and analyzing on a certain large ceramic hydraulic press, the status of key parameters can be acquired effectively during the whole pressing process. So the monitoring system supplies the significant data basis to the precise closed-loop control, accelerates the design and development of high characteristic precise closed-loop control and also strongly supports to the maintenance and upgrade with the equipments in the later period.

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