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10/9/2015SME3252: Mechatronics Lecture 4 1 Pneumatic and hydraulic actuation systems Lecture 4.

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Presentation on theme: "10/9/2015SME3252: Mechatronics Lecture 4 1 Pneumatic and hydraulic actuation systems Lecture 4."— Presentation transcript:

1 10/9/2015SME3252: Mechatronics Lecture 4 1 Pneumatic and hydraulic actuation systems Lecture 4

2 10/9/2015SME3252: Mechatronics Lecture 4 2 7.1: Actuation system Transform output of control system (i.e. µprocessor) into action (controlling) on device / machine Examples are: Electrical output from controller to a linear motion to move a load Electrical output from controller to control amount of liquid passing through a pipe ControllerActuator input Electrical signal output motion

3 10/9/2015SME3252: Mechatronics Lecture 3 3 Types Pneumatic and hydraulic actuator (Chapter 7) Mechanical actuator (Chapter 8) Electrical actuator (Chapter 9)

4 10/9/2015SME3252: Mechatronics Lecture 3 4 7.2: Pneumatic and hydraulic systems Pneumatic signals – to control final control elements The electrical signal – actuate large valve and high power control devices Drawbacks – compressibility of air Hydraulic signals – higher power control devices Drawbacks – expensive, hazards due to oil leaks

5 10/9/2015SME3252: Mechatronics Lecture 3 5 PSI (lb/in 2 ) Pounds per Square Inch determines amount of force GPM Gallons per Minute determines speed of action

6 10/9/2015SME3252: Mechatronics Lecture 3 6 PRESSURE = FORCE/AREA Find Pressure, F 2: Pressure = 10 psi 200 lbf

7 10/9/2015SME3252: Mechatronics Lecture 3 7 7.2.1: Hydraulic Actuator Tool or equipment powered by the movement of fluid under pressure. Pressurized hydraulic oil - sump Heavy duty - brakes, jacks & tractor lifts.

8 10/9/2015SME3252: Mechatronics Lecture 3 8 Hydraulic Power Supply Motor Pump Pressure relief valve Non- return valve Accumulator Oil Sump Return

9 10/9/2015SME3252: Mechatronics Lecture 3 9 Figure 7.1 (a) Hydraulic power supply, (b) accumulator

10 10/9/2015SME3252: Mechatronics Lecture 3 10

11 10/9/2015SME3252: Mechatronics Lecture 3 11 Parts of a Hydraulic System Pump - pressurize and move fluid from one part of the system to another Valves Ball Check Solenoid / power transfer Relief Filters –Remove impurities in oil Heat exchangers –Remove heat created by high pressure and moving parts Accumulators

12 10/9/2015SME3252: Mechatronics Lecture 3 12 Hydraulic Pump

13 10/9/2015SME3252: Mechatronics Lecture 3 13 Hydraulic pumps are usually one of four types: a.PISTON b.GEAR c.VANE d.INTERNAL ROTOR

14 10/9/2015SME3252: Mechatronics Lecture 4 14 a.Piston Pumps Work well at PSI’s of 2000 or more Single piston pump used in bottle jacks Require several pistons working together to generate enough volume for tractor applications Necessarily involve many moving parts Refer to Figure 7.2c for radial piston pump and 7.2d for axial piston pump

15 10/9/2015SME3252: Mechatronics Lecture 4 15 b.Gear Pumps Work well at 1500 PSI and below Work with a minimum of moving parts Less expensive to manufacture than piston type pumps Disadv. – leakage occurs

16 10/9/2015SME3252: Mechatronics Lecture 3 16 Gear Pump driven gear idler gear

17 10/9/2015SME3252: Mechatronics Lecture 3 17 c.Vane Pump

18 10/9/2015SME3252: Mechatronics Lecture 3 18 ACCUMULATORS Dampens hydraulic shock Supply of pressure if pump fails Maintain pressure without continuous pump operation Demand changes Make-up Three types –Piston –Bladder –Direct contact -

19 10/9/2015SME3252: Mechatronics Lecture 3 19 Figure 7.2 (a) Gear pump, (b) vane pump, (c) radial piston pump, (d) axial piston pump with swash plate

20 10/9/2015SME3252: Mechatronics Lecture 3 20

21 10/9/2015SME3252: Mechatronics Lecture 3 21

22 10/9/2015SME3252: Mechatronics Lecture 3 22

23 10/9/2015SME3252: Mechatronics Lecture 3 23 Application

24 10/9/2015SME3252: Mechatronics Lecture 3 24 HYDRAULIC SYSTEMS ADVANTAGES –Long distances –Great flexibility (any shape or form) –Variable speed control –Reliability DISADVANTAGES –Need for positive confinement –Oil is flammable –High pressure (typically 3000 psi) –Need for filtration

25 10/9/2015SME3252: Mechatronics Lecture 3 25 Pneumatic Actuator Compressed air Light duty CompressorAir receiver Air regulator Air 6 – 8 bar Store compressed air Set pressure Piston, Valve, switching motion

26 10/9/2015SME3252: Mechatronics Lecture 3 26 Pneumatics – Basic Principles oPneumatics – The study of the mechanical properties of air and other gasses. oA gas under pressure has the ability to exert a force  Pascal’s Law states that a compressed gas will exert pressure equally in all directions  A pressure acting over an area will result in a net force being applied

27 10/9/2015SME3252: Mechatronics Lecture 3 27 Pneumatics – Basic Principles

28 10/9/2015SME3252: Mechatronics Lecture 3 28

29 10/9/2015SME3252: Mechatronics Lecture 3 29

30 10/9/2015SME3252: Mechatronics Lecture 4 30 Pneumatic Power Supply Motor Compressor Silencer Filter Pressure relief valve Cooler Filter and water trap -dry and dust free Air receiver

31 10/9/2015SME3252: Mechatronics Lecture 3 31 Figure 7.3 Pneumatic power supply

32 10/9/2015SME3252: Mechatronics Lecture 3 32

33 10/9/2015SME3252: Mechatronics Lecture 4 33 Compressor To compress air Three types: –Piston –Screw –Diaphragm Air receiver to store compressed air Regulator to regulate the pressure Automatic power cut-off above set pressure Pressure relief valve

34 10/9/2015SME3252: Mechatronics Lecture 4 34 Compressor

35 10/9/2015SME3252: Mechatronics Lecture 3 35 Figure 7.4 (a) Single-acting, single stage, vertical, reciprocating compressor, (b) rotary vane compressor, (c) screw compressor

36 10/9/2015SME3252: Mechatronics Lecture 3 36 Pneumatic Circuit

37 10/9/2015SME3252: Mechatronics Lecture 3 37

38 10/9/2015SME3252: Mechatronics Lecture 4 38 Application – Robotic System

39 10/9/2015SME3252: Mechatronics Lecture 4 39

40 10/9/2015SME3252: Mechatronics Lecture 4 40 Exercises Power supply components for hydraulic system and pneumatic system – explain with diagram and identify difference Examples of application for both system Advantages and disadvantages of each system

41 10/9/2015SME3252: Mechatronics Lecture 4 41 End of Lecture 4


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