Upload
chester-harvey
View
216
Download
0
Embed Size (px)
DESCRIPTION
Introduction Research into Electrical, Hydraulic power as separate power sources Research into Electrical, Hydraulic power as separate power sources Little specifically comparing their advantages/disadvantages Little specifically comparing their advantages/disadvantages Doesn’t appear to be any formalized method for making the choice between them Doesn’t appear to be any formalized method for making the choice between them
Citation preview
Hydraulic and Electrical Power Design Decision
Cynthia PerreiraCynthia PerreiraIMDL and SRLIMDL and SRL
Dr. Book and Dr. ParedisDr. Book and Dr. ParedisFebruary 21, 2003February 21, 2003
Introduction Two major power sources for mechanical devicesTwo major power sources for mechanical devices
Electrical Electrical HydraulicHydraulic
Decision not always made in best, most informed Decision not always made in best, most informed mannermanner
Decision is often made too early in the design Decision is often made too early in the design processprocess
Develop method of dealing with this type of Develop method of dealing with this type of decisiondecision
Introduction
Research into Electrical, Hydraulic power Research into Electrical, Hydraulic power as separate power sourcesas separate power sources
Little specifically comparing their Little specifically comparing their advantages/disadvantagesadvantages/disadvantages
Doesn’t appear to be any formalized Doesn’t appear to be any formalized method for making the choice between method for making the choice between themthem
Approach1.1. Develop a method for choosing between two familiesDevelop a method for choosing between two families
• Multiple Levels of choices/modelingMultiple Levels of choices/modeling• Performance MeasurementsPerformance Measurements• Develop systematic methodDevelop systematic method
2.2. Examine an example and apply the methodExamine an example and apply the method• Understand current technology choicesUnderstand current technology choices• Add to proposed methodAdd to proposed method• Apply proposed methodApply proposed method• Examine resultsExamine results
Power Tree Inside each family of power there are many Inside each family of power there are many
difference optionsdifference options
Composition
Selection
Electric Hydraulic Pneumatic
Drive System
OROR
linkagecylinder
ValvesActuator Pump
Rotational Translational Rotational Translational
OR OR
AND AND
AND
Multiple Levels of Modeling Selection between two Selection between two
families of solutionsfamilies of solutions Best family = family Best family = family
containing the best containing the best instanceinstance
Requires design Requires design knowledgeknowledge
Models at different levels Models at different levels of abstractionof abstraction
Hydraulic
Electrical
Performance
H
E
Levels of Modeling Simple modelsSimple models
F=maF=ma P=TvP=Tv
Rules of thumbRules of thumb Known values for groups of componentsKnown values for groups of components SimulationSimulation
MatlabMatlab ModelicaModelica
Performance Measurements Power outputPower output Velocity, TorqueVelocity, Torque Geometry, space requiredGeometry, space required WeightWeight EfficiencyEfficiency CostCost NoiseNoise Other application specific factorsOther application specific factors
Applications of Fluid Power AutomotiveAutomotive
DriveDrive BrakesBrakes Power SteeringPower Steering
Manufacturing machineryManufacturing machinery Construction equipmentConstruction equipment
LoadersLoaders CranesCranes BulldozersBulldozers
RobotsRobots ElevatorsElevators
Power Steering Example Technology that lends Technology that lends
itself well to the use itself well to the use of either hydraulic or of either hydraulic or electrical powerelectrical power
Currently dominated Currently dominated by hydraulicsby hydraulics
Electro-hydraulic Electro-hydraulic systemssystems
Electrical recently Electrical recently implemented in some implemented in some new small carsnew small cars
***Contacts with NSK, Ford, Siemens
Hydraulic Power Steering
Electro-hydraulic Systems
Electric motor to power steering pumpElectric motor to power steering pump Speed of motor can be varied or turned offSpeed of motor can be varied or turned off Can be used for large and small vehiclesCan be used for large and small vehicles AdvantagesAdvantages
Better fuel efficiencyBetter fuel efficiency Motor can turn off when not in useMotor can turn off when not in use Less energy consumptionLess energy consumption
Electrical Power Steering
Electrical Power Steering AdvantagesAdvantages
EnvironmentEnvironment Off when not turningOff when not turning Lower weight and sizeLower weight and size Energy consumption as little as 1/20 of hydraulicEnergy consumption as little as 1/20 of hydraulic Can reduce fuel consumption by 3-5%Can reduce fuel consumption by 3-5% Contains no oilContains no oil
Better feel when drivingBetter feel when driving Reduced rattling noiseReduced rattling noise
DisadvantagesDisadvantages CostCost Low force output – only currently suitable for small carsLow force output – only currently suitable for small cars
42V may allow the system to be used in heavier vehicles with larger tire contact 42V may allow the system to be used in heavier vehicles with larger tire contact patches patches
Now present in 2002 Saturn Vue, Honda Civic SI, Honda InsightNow present in 2002 Saturn Vue, Honda Civic SI, Honda Insight
Future Work
Further develop systematic methodFurther develop systematic method Determine levels of modeling and Determine levels of modeling and
information needed at eachinformation needed at each Relate measures of performance to Relate measures of performance to
customer’s wishescustomer’s wishes Continue with power steering exampleContinue with power steering example Continue contacts with Ford, NSKContinue contacts with Ford, NSK
Questions?