scholarly journals Identification of Contamination Control Strategy for Fluid Power System Using an Inexact Chance-Constrained Integer Program

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
Y. Q. Huang ◽  
S. L. Nie ◽  
H. Ji
Keyword(s):  
Power System ◽  
Fluid Power ◽  
Mixed Integer ◽  
Chance Constrained Programming ◽  
Constraint Violation ◽  
Contamination Control ◽  
System Cost ◽  
Risk Levels ◽  
Depth Analysis ◽  
Fluid Power System

An inexact chance-constrained integer programming (ICIP) method is developed for planning contamination control of fluid power system (FPS). The ICIP is derived by incorporating chance-constrained programming (CCP) within an interval mixed integer linear programming (IMILP) framework, such that uncertainties presented in terms of probability distributions and discrete intervals can be handled. It can also help examine the reliability of satisfying (or risk of violating) system constraints under uncertainty. The developed method is applied to a case of contamination control planning for one typical FPS. Interval solutions associated with risk levels of constraint violation are obtained. They can be used for generating decision alternatives and thus help designers identify desired strategies under various environmental, economic, and system reliability constraints. Generally, willingness to take a higher risk of constraint violation will guarantee a lower system cost; a strong desire to acquire a lower risk will run into a higher system cost. Thus, the method provides not only decision variable solutions presented as stable intervals but also the associated risk levels in violating the system constraints. It can therefore support an in-depth analysis of the tradeoff between system cost and system-failure risk.

ROBUST INTERVAL-BASED MINIMAX-REGRET ANALYSIS METHOD FOR FILTER MANAGEMENT OF FLUID POWER SYSTEM

2013 ◽  
Vol 30 (06) ◽  
pp. 1350021
Author(s):  
SONGLIN NIE ◽  
HUI JI ◽  
YEQING HUANG ◽  
ZHEN HU ◽  
YONGPING LI
Keyword(s):  
Power System ◽  
Optimal Strategies ◽  
Decision Makers ◽  
Fluid Power ◽  
Maintenance Cost ◽  
Minimax Regret ◽  
Fluid Power System ◽  
System Maintenance ◽  
Management Alternatives

Fluid contamination is one of the main reasons for the wear failure and the related downtime in a hydraulic power system. Filters play an important role in controlling the contamination effectively, increasing the reliability of the system, and maintaining the system economically. Due to the uncertainties of system parameters, the complicated relationship among components, as well as the lack of effective approach, managing filters is becoming one of the biggest challenges for engineers and decision makers. In this study, a robust interval-based minimax-regret analysis (RIMA) method is developed for the filter management in a fluid power system (FPS) under uncertainty. The RIMA method can handle the uncertainties existed in contaminant ingressions of the system and contaminant holding capacity of filters without making assumption on probabilistic distributions for random variables. Through analyzing the system cost of all possible filter management alternatives, an interval element regret matrix can be obtained, which enables decision makers to identify the optimal filter management strategy under uncertainty. The results of a case study indicate that the reasonable solutions generated can help decision makers understand the consequence of short-term and long-term decisions, identify optimal strategies for filter allocation and selection with minimized system-maintenance cost and system-failure risk.

Design Methodology for Fluid Power Systems Using Hypermedia

1999 ◽  
Author(s):  
Edmund J. Hughes ◽  
Thomas G. Richards ◽  
Derek G. Tilley
Keyword(s):  
Power Systems ◽  
Power System ◽  
System Design ◽  
Good Practice ◽  
Practical Experience ◽  
Design Tool ◽  
Fluid Power ◽  
Specific Information ◽  
Fluid Power System ◽  
Fluid Power Systems

Abstract Fluid power system design is a skilful and complex task requiring significant practical experience and heuristic knowledge gained over many years. Industries specifying and/or designing fluid power systems in their products are at risk should they lose key personnel with this knowledge. This problem is compounded by a lack of formal training at the graduate level, creating a shortfall in qualified fluid power designers. Design support tools that assist and guide designers in their work, as part of a Concurrent Engineering approach, should be capable of providing both good practice guidance and a framework into which product specific information can be stored for later reuse. This paper discusses the early development of a fluid power system design tool that seeks to offer this support using a methodology developed in hypermedia.

scholarly journals Single Channel Hybrid FES Gait Assist System

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
A. Kangude ◽  
B. Burgstahler ◽  
J. Katsys ◽  
W. Durfee
Keyword(s):  
Energy Storage ◽  
Power System ◽  
Single Channel ◽  
Human Subjects ◽  
Fluid Power ◽  
Knee Joints ◽  
Transfer Energy ◽  
Thoracic Level ◽  
Cord Injury ◽  
Fluid Power System

Loss of mobility due to lower limb paralysis is common consequence of thoracic level spinal cord injury (SCI). In the US there are approximately 253,000 persons with SCI. The wheelchair is the most common form of mobility for individuals with paraplegia but there remains a need for assistive technology that can enable paraplegics to walk and reach in the periphery of wheelchair. A new concept is presented that combines functional electrical stimulation (FES) with an energy storing orthosis (ESO) that contains a fluid power system to store and transfer energy during the gait cycle. Elastic energy storage elements on the orthosis hip and knee joints hold the leg in a flexed equilibrium position. Stimulation of the quadriceps extends the knee, placing excess energy in both the equilibrium spring and an energy transfer element. The stored energy is transferred to the hip where it is discharged and used to extend the hip against its equilibrium spring which also aids in forward progression. A new step is initiated by releasing the hip and knee joints from the straight leg position to the flexed position. The concept is realized using gas springs and pneumatic cylinders. Gas springs act as flexed energy storage elements. Lower air cylinder and the tubing acts as an accumulator and the upper cylinder acts as hip joint actuator. The system uses 2 way proportional solenoid actuated pneumatic valves for control during extension. The conceptual design of the ESO was completed and implemented in a dynamic simulation model (MSC ADAMS) and in a benchtop prototype for engineering measurements. Of the 14 joules of energy available from quadriceps, 8.9 joules of energy is utilized for doing work against springs and inertial forces; 5.4 joules is stored in pneumatic system; of which 1.4 joules is required for hip extensions and the remaining will be used for forward progression. No studies were conducted with human subjects. A hydraulic fluid power system was investigated for better control and braking possibilities but was not adopted because of difficulities in accumulator design and high fluid friction losses. A Matlab code was used to calculate the torques required at joints to support standing. Commerical braces are being used for improved user comfort. A wrap spring brake is being designed to maintain standing posture without FES or any active energy input. Technical feasibility of the ESO prototype will be evaluated using two subjects with paraplegia.

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.

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