Synthetic Esters and Dynamics of Pressure Compensated Proportional Directional Control Valves

2018 ◽  
Author(s):  
J. H. Jakobsen ◽  
M. R. Hansen
Keyword(s):  
Closed Loop ◽  
Closed Loop Control ◽  
Third Order ◽  
Loop Control ◽  
Synthetic Ester ◽  
Frequency Responses ◽  
Directional Control ◽  
Test Parameters ◽  
The Difference

The purpose of this paper is to help reduce the uncertainty in behavior introduced when changing hydraulic oil from mineral oil (HLP) to biodegradable oil (synthetic esters - HEES) by comparing the behavior of proportional valves with HLP and with HEES at various temperatures. The focus of this article is on classic proportional valves used in the industry. The study is based on tests and modelling with characterization of dynamic behavior in mind. The characterization is based on tests of two pressure compensated proportional valves, one with closed loop control of the spool position, and one without. The two ester types tested are one based on a saturated, fully synthetic ester and a regular fully synthetic ester. The tests consist of steps and frequency responses. Both valves are tested at oil temperatures 20°C, 40°C and 60°C. The adopted models are based on a third order linear model with parameters identified using frequency responses from actual valve tests. The variation of amplitude and bias has some influence on the resulting frequency response especially at lower temperatures. But the general tendencies are unaffected by amplitude and bias. As expected a clear tendency for both valves of increasing dampening at decreasing temperatures is seen regardless of oil type, but the increase in dampening is similar for all oil types. The saturated ester leads to less bandwidth at lower temperatures for both valves, but the overall variations between all oil types stay within 1.66Hz of each other when tested with the same test parameters. The investigation indicates that the difference in dynamic characteristics at 20°C caused by the different oil types can not be explained with variations in any single one of the classic liquid properties density and viscosity and more investigations are needed to identify the cause.

scholarly journals Experimental characterization of Drobot: Towards closed-loop control

2014 ◽  
Author(s):  
Nathalie Majcherczyk ◽  
Kanty Rabenorosoa ◽  
Cedric Clevy ◽  
Rosica Mincheva ◽  
Jean-Marie Raquez ◽  
...  
Keyword(s):  
Closed Loop ◽  
Closed Loop Control ◽  
Experimental Characterization ◽  
Loop Control

Closed-Loop Control of the Frequency Response of the Virtual Brain Model

2017 ◽  
Author(s):  
Christine Beauchene ◽  
Alexander Leonessa ◽  
Subhradeep Roy ◽  
James Simon ◽  
Nicole Abaid
Keyword(s):  
Large Scale ◽  
Closed Loop ◽  
Brain Connectivity ◽  
Brain Activity ◽  
Closed Loop Control ◽  
Loop Control ◽  
Non Invasive ◽  
Frequency Mismatch ◽  
Stimulation Method ◽  
The Difference

The brain is a highly complex network and analyzing brain connectivity is a nontrivial task. Consequently, the neuroscience community created a large-scale, customizable, mathematical model which simulates brain activity called The Virtual Brain (TVB). Using TVB, we seek to control electroencephalography (EEG) measured brain states using auditory inputs, through TVB. A safe non-invasive brain stimulation method is binaural beats (BB) which arise from the brain’s interpretation of two pure tones, with a small frequency mismatch, delivered independently to each ear. A third phantom BB, whose frequency is equal to the difference of the two presented tones, is produced. This paper details the development and proof-of-concept testing of a simulation environment for an EEG-based closed-loop control of TVB using BB. Results suggest that the connectivity networks, constructed from simulated EEG, may change with certain BB stimulation frequency. In this work, we demonstrate that a linear controller can successfully modulate TVB connectivity.

scholarly journals Improvement of Silicon Nanotweezers Sensitivity for Mechanical Characterization of Biomolecules Using Closed-Loop Control

2015 ◽  
Vol 20 (3) ◽  
pp. 1418-1427 ◽  
Author(s):  
Nicolas Lafitte ◽  
Yassine Haddab ◽  
Yann Le Gorrec ◽  
Herve Guillou ◽  
Momoko Kumemura ◽  
...  
Keyword(s):  
Closed Loop ◽  
Mechanical Characterization ◽  
Closed Loop Control ◽  
Loop Control

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.

Analysis on EPS Machitrical Dual Closed-Loop Control System

2012 ◽  
Vol 241-244 ◽  
pp. 1071-1075
Author(s):  
Wan Ying Wei ◽  
Jin Ying Chen ◽  
Gang Xie
Keyword(s):  
Control System ◽  
Fuzzy Control ◽  
Pid Control ◽  
Closed Loop ◽  
Steering System ◽  
Closed Loop Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
The Difference

The electric power steering system (EPS) is a combination of mechanical and electrical control system. EPS’control strategy used commonly has two kinds: current PID control and fuzzy control .The current PID control based on the difference between target current and feedback current is a curren closed-loop control system and the fuzzy control is a mechanical closed-loop control system based on the difference between forces of the upper part and the lower part of the steering shaft . Taking the margin of the mechanical and electrical closed-loop control system, this paper, a torque feedback loop for the outer ring, a current feedback loop as the inner loop, designed a dual-loop control system, the output of the fuzzy control determined a target current, and then proceed to current PID control, fast-track the target torque. The simulation shows the dual closed-loop fuzzy PID control is superior to two commonly used control strategies so that electric power steering system has a better tracking ability and stability.

scholarly journals SISTEM KONTROL SUHU PADA PENGERING IKAN BERBASIS MIKROKONTROLER ATMEGA 8535

2020 ◽  
Vol 5 (2) ◽  
pp. 87-95
Author(s):  
Fredy M. Baitanu ◽  
Ali Warsito ◽  
Jonshon Tarigan
Keyword(s):  
Closed Loop ◽  
Dry Mass ◽  
Temperature Data ◽  
Closed Loop Control ◽  
Electronic Market ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Measurement Results ◽  
Loop Control System ◽  
The Difference

Abstrak Telah dirancang sebuah sistem kontrol secara loop tertutup pada unit pengeringan ikan menggunakan sensor LM35, mikrokontroler ATmega8535, seven segment serta beberapa komponen elektronika yang tesedia dipasaran. Sistem dikendalikan oleh mikrokontroler ATmega8535 untuk pengambilan data suhu menggunakan sensor LM35 dan menampilkan data suhu melalui seven segment, serta mengontrol pemanas melalui aktuator. Hasil pengukuran nilai suhu akan dibandingkan dengan nilai setpoint, sehingga diperoleh selisih nilai yang akan digunakan sebagai indikator untuk melakukan proses pengontrolan. Hasil pengujian menunjukkan bahwa pengontrolan bekerja dengan baik dalam merespon setiap perubahan suhu udara. Ketika suhu di bawah setpoint 53°C maka aktuator akan berada dalam kondisi on sehingga pemanas aktif, sebaliknya jika suhu berada di atas setpoint 53°C maka aktuator akan berada dalam kondisi off untuk mematikan heater. Hasil pengeringan selama 4 jam menunjukkan bahwa pengeringan ikan pada massabasah ikan 200 gram, yaitu pada keadaan ventilasi atas kotak pengeringan terbukaakan menghasilkan massa kering90 gram. Pengujian selama 4 jam pada keadaan ventilasi kotak pengeringan tertutup akan menghasilkan massa kering 130 gram. Selain itu, pengeringan secara tradisional selama 12 jam dengan massa basah ikan 200-gram akan menghasilkan massa kering 90 gram.Kata Kunci: Suhu, pengeringan ikan; mikrokontroler Atmega8535; seven segment; aktuator Abstract A closed-loop control system of temperatures in fish drying unit using LM35 sensor, ATmega8535 microcontroller, seven segment and also some of the available electronic market components has been designed. The system is controlled by a microcontroller ATmega8535 for temperature data collection using LM35 sensor and temperature data is displayed on seven segments, as well as heating control via actuators. The measurement results will be compared with the value of the temperature set point value in order to obtain the difference in value to be used as an indicator for process control. The results show that the control works well in response to any changes in air temperature. If the setpoint temperature below 53°C, the actuator will in on condition that the heating is on, otherwise if the temperature is above 53°C setpoint then the actuator will on condition to turn the heater off. Drying for 4 hours results show that the drying fish on the fish wet mass of 200 grams, which is the state of the top vents open drying box will produce a dry mass of 90 grams. Testing for 4 hours in a drying box vents closed state will produce 130 grams of dry mass. In addition, traditional drying for 12 hours with 200 grams of fish wet mass will produce 90 grams of dry mass.Keywords: Temperature; drying fish; ATmega8535 microcontroller; seven segments; actuators.

Control of the Fabrication of Long Slender Workpieces of Arbitrary Shape—Part II: Closed-Loop Control of the Multi-Axis Bending Process

1996 ◽  
Vol 118 (3) ◽  
pp. 549-556 ◽  
Author(s):  
J. X. Luo ◽  
D. L. Joynt ◽  
K. A. Stelson
Keyword(s):  
Feedback Control ◽  
Laser Scanning ◽  
Closed Loop ◽  
Transfer Functions ◽  
Shape Representation ◽  
Closed Loop Control ◽  
Loop Control ◽  
Bending Process ◽  
Shape Errors ◽  
The Difference

A feedback control scheme for the multi-axis bending process is presented. The closed-loop control is derived from transfer functions that represent the bending and twisting processes. The dynamics of these processes are due to the convection of shape between the bending dies during deformation. The success of the feedback control also depends on accurate measurement of part shape. A method based on laser scanning has been developed to find the intrinsic shape representation of the measured workpiece. Shape errors are defined as the difference between the intrinsic geometric quantities of the actual and desired part. By applying shape errors to the inverse transfer functions, we can obtain incremental changes in the axis control commands. Experimental results demonstrate that the feedback control causes shape errors to decrease on subsequent iterations.

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