scholarly journals A Multi-mode Electronic Load Sensing Control Scheme with Power Limitation and Pressure Cut-off for Mobile Machinery

2021 ◽  
Author(s):  
Min Cheng ◽  
Bolin Sun ◽  
Ruqi Ding ◽  
Bing Xu
Keyword(s):  
Pressure Control ◽  
System Level ◽  
Load Sensing ◽  
Stability Performance ◽  
Control Functions ◽  
Control Scheme ◽  
Control Load ◽  
Mobile Machinery ◽  
Electronic Load ◽  
Multi Mode

Abstract In mobile machinery, hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level, but diversified control functions(e. g., power limitation and pressure cut-off) are integrated into the electronic controller only from the pump level, leading to the potential instability of the overall system. To solve this problem, a multi-mode electrohydraulic load sensing (MELS) control scheme is proposed especially considering the switching stability from the system level, which includes four working modes of flow control, load sensing, power limitation, and pressure control. Combined with defined control priority, a switching rule including bilateral and unilateral switching for different modes is then established according to the actual requirements of mobile machinery. A comparative study was carried out based on a test rig with a 2-ton hydraulic excavator. The results show that the MELS controller can achieve the control functions of proper flow supplement, power limitation, and pressure control, which has good stability performance when switching between different control modes.

Modeling and Control of a Teletruck Using Electronic Load Sensing

2010 ◽  
Author(s):  
Rico H. Hansen ◽  
Asger M. Iversen ◽  
Mads S. Jensen ◽  
Torben O. Andersen ◽  
Henrik C. Pedersen
Keyword(s):  
Power System ◽  
Controller Design ◽  
Dynamic Performance ◽  
Pressure Control ◽  
Control Flow ◽  
Fluid Power ◽  
Modeling And Control ◽  
Load Sensing ◽  
Fluid Power System ◽  
Electronic Load

In mobile hydraulic application the actuating fluid power system is most commonly controlled using a hydro-mechanical control scheme called Hydraulic Load Sensing (HLS). However, with the demands for increased efficiency and controllability the HLS solutions are reaching their limits. Motivated by availability of electronic controllable fluid power components and the potential of increased dynamic performance and efficiency, this paper investigates how HLS can be replaced with electronic control, i.e. Electronic Load Sensing (ELS). The investigation is performed by taking a specific application, a teletruck, and replace the HLS control with ELS. To aid the controller design for the ELS system, a complete model of the teletruck’s articulated arm and fluid power system is developed. To show the feasibility, a preliminary control structure for the ELS system is developed. The controller is tested on the machine, validating that features such as pump pressure control, flow sharing and over pressure protection can be implemented using ELS and with improved energy efficiency.

A double variable control load sensing system for electric hydraulic excavator

Energy ◽  
2021 ◽  
Vol 223 ◽  
pp. 119999
Author(s):  
Tianliang Lin ◽  
Yuanzheng Lin ◽  
Haoling Ren ◽  
Haibin Chen ◽  
Zhongshen Li ◽  
...  
Keyword(s):  
Hydraulic Excavator ◽  
Load Sensing ◽  
Sensing System ◽  
Variable Control ◽  
Control Load

Abstract P183: Minimal Impact of JAMA 2014 Guidelines on Blood Pressure Control in a Large Health System

Circulation ◽  
2017 ◽  
Vol 135 (suppl_1) ◽  
Author(s):  
Alex R Chang ◽  
J E Hartle ◽  
Lawrence Appel ◽  
Morgan Grams
Keyword(s):  
Blood Pressure ◽  
Health System ◽  
Blood Pressure Control ◽  
Pressure Control ◽  
Mixed Effects Models ◽  
System Level ◽  
Minimal Impact ◽  
Before And After ◽  
Patients With Diabetes ◽  
Using Data

Background: JAMA 2014 blood pressure (BP) guidelines raised BP goals for adults older than 60 years (from <140/90 to <150/90) and adults with chronic kidney disease (CKD) or diabetes (from < 130/80 to <140/90). It is unknown whether there were changes in BP control at the health system level after guideline publication. Methods: Using data from 288,962 adults receiving primary care in the Geisinger Health System, we compared blood pressure control over 1-year time periods before and after the February 2014 publication of the JAMA 2014 BP guidelines (i.e. Aug 2012-July 2013 vs Aug 2014-July 2015). Mixed effects models were used, allowing intercepts to vary by individual, adjusted for age, gender, and race. Results: Mean age was 49.2 ± 18.3 y, 56.7% were female, and 2.5% were black. Prevalence of diagnoses for hypertension, diabetes, and CKD were 40.0%, 15.1%, and 11.4%, respectively. Overall, distributions of systolic BP were similar before and after JAMA 2014 BP guidelines (Figure). BP control <140/90 was also similar between the two periods for adults 18-59 y (90.9% vs. 90.3%; OR 1.01, 95% CI: 0.99-1.02; p=0.3), adults ≥ 60 y (81.8% vs 82.2%; OR 1.01, 95% CI: 1.00-1.03; p=0.05), and adults with diabetes (83.2% vs. 82.7%; OR 1.00, 95% CI: 0.99-1.02; p=0.7) whereas BP control <140/90 improved slightly for adults with CKD (81.7% vs. 82.1%; OR 1.06, 95% CI: 1.04-1.08; p<0.001). BP control <130/80 was marginally worse after JAMA 2014 BP guidelines in patients with diabetes (53.5% vs. 51.8%; OR 0.98, 95% CI: 0.96-0.99; p=0.01). Trends were similar in analyses only including patients with hypertension diagnoses (overall 78.6% vs. 78.2%, OR 1.00, 95% CI: 0.99-1.02; p=0.5), and when using a goal of < 130/80 for patients with CKD (53.3% vs. 53.5%; OR 1.06, 95% CI: 1.04-1.08; p<0.001). Conclusion: There was little change in blood pressure control in a large integrated health system after publication of the JAMA 2014 BP guidelines. These findings are reassuring given recent findings from the SPRINT trial supporting lower BP goals.

scholarly journals A Control Scheme with the Variable-Speed Pitch System for Wind Turbines during a Zero-Voltage Ride Through

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3344
Author(s):  
Enyu Cai ◽  
Yunqiang Yan ◽  
Lei Dong ◽  
Xiaozhong Liao
Keyword(s):  
Wind Turbines ◽  
Low Voltage ◽  
System Modeling ◽  
Fault Analysis ◽  
System Level ◽  
Level Control ◽  
Control Logic ◽  
Control Scheme ◽  
Pitch System ◽  
Zero Voltage

Zero-voltage ride through (ZVRT) is the extreme case of low-voltage ride through (LVRT), which represents the optimal grid-connection capability of wind turbines (WTs). Enforcing ZVRT will improve the dynamic performance of WTs and therefore significantly enhance the resiliency of renewable-rich grids. A control scheme that includes a pitch system is an essential control aspect of WTs riding through voltage dips; however, the existing control scheme with a pitch system for LVRT cannot distinguish between a ZVRT status and a power-loss condition, and, consequently, does not meet the ZVRT requirements. A system-level control scheme with a pitch system for ZVRT that includes pitch system modeling, control logic, control circuits, and overspeed protection control (OPC) is proposed in this paper for the first time in ZVRT research. Additionally, the field data are shared, a fault analysis of an overspeed accident caused by a voltage dip that describes the operating status at the WT-collapse moment is presented, and some existing WT design flaws are revealed and corrected by the fault analysis. Finally, the pitching performance during a ZVRT, which significantly affects the ZVRT performance of the WT, is obtained from laboratory and field tests. The results validate the effectiveness of the proposed holistic control scheme.

Research on Integrated Control System of the Gas Pressure in Coke Oven

2013 ◽  
Vol 397-400 ◽  
pp. 1214-1219
Author(s):  
Xia Bai ◽  
Da Lu Guan ◽  
Chen Rui
Keyword(s):  
Control System ◽  
Control Strategies ◽  
Integrated Control ◽  
Control Object ◽  
Coke Oven ◽  
Pressure Control ◽  
Expert Control ◽  
Control Scheme ◽  
Hardware Reliability ◽  
Pressure Control System

This paper combines hardware reliability and software mobility with modern intelligent control through the analysis of the control object using intelligent decoupling control scheme to control the pressure control system of the large gas collector in coke oven. By using expert control strategies based on the DCS, the paper develops the system design which is versatile and effective.

scholarly journals Multitechnique Concise Robust Control for the Insulation Containment Space Pressure Control of LNG Carrier

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Zuojing Su ◽  
Xianku Zhang ◽  
Xu Han
Keyword(s):  
Time Delay ◽  
Robust Control ◽  
Energy Saving ◽  
Pressure Control ◽  
Smith Predictor ◽  
Mapping Technique ◽  
Delay Model ◽  
Nonlinear Feedback ◽  
Maintenance System ◽  
Control Scheme

In this note, a novel multitechnique concise robust control scheme, based on the mirror mapping technique (MMT), closed-loop gain shaping algorithm (CGSA), Smith predictor (SP), and nonlinear feedback technique (NFT), is proposed for the pressure control of the liquefied natural gas (LNG) carrier insulation containment space. Firstly, a kind of integral unstable time-delay model is obtained by linearizing the nonlinear model of the pressure maintenance system around its equilibrium. By using the MMT and CGSA, one acquires the corresponding stable mirror mapping model of the unstable linear model and the designed controller. And the SP is introduced to tackle the time-delay problem. In addition, for the purpose of energy saving, the NFT is added into the control scheme. Finally, a set of experiments has been employed to illustrate the control effects, and the results show that it can achieve satisfying performance in aspects of disturbance rejection and energy saving.

scholarly journals Control System Based on Anode Offgas Recycle for Solid Oxide Fuel Cell System

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Shuanghong Li ◽  
Chengjun Zhan ◽  
Yupu Yang
Keyword(s):  
Control System ◽  
Decoupling Control ◽  
System Level ◽  
System Control ◽  
Electrical Characteristics ◽  
Electrical Parameters ◽  
Temperature Controller ◽  
Load Following ◽  
System Level Simulation ◽  
Control Scheme

The conflicting operation objectives between rapid load following and the fuel depletion avoidance as well as the strong interactions between the thermal and electrical parameters make the SOFC system difficult to control. This study focuses on the design of the decoupling control for the thermal and electrical characteristics of the SOFC system through anode offgas recycling (AOR). The decoupling control system can independently manipulate the thermal and electrical parameters, which interact with one another in most cases, such as stack temperatures, burner temperature, system current, and system power. Under the decoupling control scheme, the AOR is taken as a manipulation variable. The burner controller maintains the burner temperature without being affected by abrupt power change. The stack temperature controller properly coordinates with the burner temperature controller to independently modulate the stack thermal parameters. For the electrical problems, the decoupling control scheme shows its superiority over the conventional controller in alleviating rapid load following and fuel depletion avoidance. System-level simulation under a power-changing case is performed to validate the control freedom between the thermal and electrical characteristics as well as the stability, efficiency, and robustness of the novel system control scheme.

Intelligent Environmental Monitoring and Automation System

2013 ◽  
Vol 418 ◽  
pp. 108-111 ◽  
Author(s):  
Jui Ho Chen ◽  
Wen Tsai Sung ◽  
Hsi Chun Wang ◽  
Chun Yen Chung
Keyword(s):  
Automation System ◽  
Signal Acquisition ◽  
Server Side ◽  
Control Functions ◽  
Sensor Module ◽  
Chip Processing ◽  
Control Load ◽  
Acquisition Device ◽  
Sensor Signals ◽  
Environmental Requirements

This study production of smart house to show the entire system, the use of self-sensing module and the 8051 monocrystal chip processing sensor signals, the success achieved with the measurement of temperature, humidity, illumination, carbon monoxide sensor module. The way transmits by wireless (ZigBee chips) and wired (DAQ signal acquisition device) sensor value send to the server-side carries on remote monitoring and record etc. In accordance with environmental requirements set in the server-side sensing value, using the infrared ray way automatic control load. When necessity also can use the available hand-hold remote control, dual control functions to enable the environment to be safer and the comfortable home life.

A Hybrid Displacement/Pressure Control Scheme for an Electrohydraulic Flow Matching System

2015 ◽  
Vol 20 (6) ◽  
pp. 2771-2782 ◽  
Author(s):  
Bing Xu ◽  
Min Cheng ◽  
Huayong Yang ◽  
Junhui Zhang ◽  
Chunshuang Sun
Keyword(s):  
Pressure Control ◽  
Control Scheme
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