Class 12 - Mathematical Modeling Of Hydraulic System

System Modeling Coursework

Class 12: Modeling of Hydraulic systems

P.R. VENKATESWARAN Faculty, Instrumentation and Control Engineering, Manipal Institute of Technology, Manipal Karnataka 576 104 INDIA Ph: 0820 2925154, 2925152 Fax: 0820 2571071 Email: [email protected], [email protected] Web address: http://www.esnips.com/web/SystemModelingClassNotes

WARNING! • I claim no originality in all these notes. These are the compilation from various sources for the purpose of delivering lectures. I humbly acknowledge the wonderful help provided by the original sources in this compilation. • For best results, it is always suggested you read the source material. • Of late, this has becoming supplement to what is taught in the class. So BEWARE! You are on two tracks!

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Contents • Description of a hydraulic system • Model of the hydraulic system • Some questions.

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Hydraulic devices • They are used in hydraulic feedback systems and in combined electro-mechanical-hydraulic systems. • In hydraulic devices, power is transmitted through the action of fluid flow under pressure and the fluid is incompressible. • The fluid used are petroleum based oils and non – inflammable synthetic oils.

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Classification of hydraulic devices • Hydraulic devices used in control systems are generally classified as hydraulic motors and hydraulic linear actuators. • The output of a hydraulic motor is rotary motion and that of linear actuator is translational. The hydraulic motor is physically smaller in size than an electric motor for the same output. • Applications are power steering and brakes in automobiles, steering mechanisms in large ships, control of machine tools etc. July – December 2008

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Advantages of hydraulic devices • Hydraulic fluid acts as a lubricant and coolant • Comparatively small sized hydraulic actuators can develop large forces or torques • Hydraulic actuators can be operated under continuous, intermittent reversing and stalled conditions without damage • Hydraulic actuators have a higher speed of response. They offer fast starts, stops and speed reversals. July – December 2008

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Advantages of Hydraulic devices • With availability of both linear and rotary actuators, the design has become more flexible. • Because of low leakages in hydraulic actuators, when loads are applied the drop in speed will be small. • Hydraulic components are more rugged than their counterparts

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Disadvantages of hydraulic devices • Hydraulic power is not readily available compared to electric power • Inherent problems of leaks and sealing them against foreign particles • Operating noise • Costs more compared to electrical system • Fire and explosion hazards exist • Hydraulic lines are not flexible as electric cables • Highly non linear response July – December 2008

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Find the transfer function of this system

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Description of the system

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Try the rest!

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References 1. Advanced Control Systems Engineering, Ronald Burns 2. Modern Control Engineering, Ogata 3. Control Systems, Nagoor Kani …amongst others

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And, before we break… • Life is ten percent what you make it and ninety percent how to take it

Thanks for listening…

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