Actuators in Mechatronic Systems

Course Information

• Course title: Interfacing for Mechatronic Systems
• Course code: WSC353
• Lecturers: Dr Gianfranco Claudio & Dr Tim Harrison
• University: Loughborough University

Lecture Plan

• Sensors (1): October 31st, 14:00
• Sensors (2): November 7th, 14:00
• Strain Gauges, Charge Amplifiers, Sensor Networks & Relays: November 14th, 14:00
• Actuators (1): November 21st, 14:00
• Actuators (2): November 28th, 14:00
• Thermal and Noise considerations: December 5th, 14:00
• Some practical examples: December 12th, 14:00

###Learning Outcomes

• Understand the different types of actuators.
• Understand how actuators work.
• Understand how to interface with actuators.
• Understand the advantages and limitations of actuators.

Overview (Diagram)

• Diagram of actuation process involving microcontroller, analogue conversion, filtering, gliching, amplifier, actuator, linkage, and environment.

Why Study Actuators?

• Actuators are equally important as sensors.
• Many techniques and information apply to actuators as they do sensors.
• Understanding voltage vs. current sensor/actuator networks.
• Understanding DAC/ADC.
• Recognizing noise aspects.

Overview (Actuation System)

• Shows a simple block diagram of an actuator system.
• Includes energy source, power supply, power amplifier, actuator, and to physical system connections.
• Different components of a mechanical system

Types of Actuator Systems

• Shape Memory Alloys (SMAs): metal alloys that revert to their original shape. Nickel-Titanium (Ni-Ti) is a common type with high force-to-weight ratio but low efficiency.
• Rheological Fluids: materials that change their properties with an external field (e.g. electric, magnetic). Electro-Rheological (ER) fluids: use electric fields and can be very fast acting and direct. A polymer suspended in a silicone fluid. High electric fields required. Magnet-Rheological (MR) fluids: use magnetic fields and are heavy, and easily degraded.
• Electro-active polymers (EAPs): are modified by voltage; 2 types (dielectric and ionic).
• Piezoelectric: voltage creates a mechanical effect; materials and actuators widely available (square, rectangular, ring shape).
• Solenoids: Actuate linearly; Simple and robust, large variation of size/force; Not fully variable.
• Fluid Systems: Hydraulics and pneumatics. Often used for situations with large power requirements.

Fluid Systems - Advantages and Disadvantages

• Advantages: High power density, safety in explosive environments, Less susceptible to electrical interference, useful when electrical supply is not available.
• Disadvantages: Leaks, loss of efficiency, not as quick as electric systems.

Working Fluids

• Water is rarely used today but was historically important.
• Oil is generally preferred for hydraulics and can be used at high pressures and has a good temperature range, but needs to be non-toxic.
• Air has numerous applications in pneumatics and easier to store and maintain.

Fluid Systems (Components)

• Diagram of systems showing components like pump, valve, cylinder, and reservoir.
• Various types of pumps, valves, and cylinders are illustrated, with specifics like piston pumps, gear pumps, swashplate pumps, and different valves based on action methods (poppet or spool). Pneumatic and hydraulic systems.

This quiz focuses on understanding different types of actuators, their workings, and interfacing techniques in mechatronic systems. Participants will explore practical examples and gain insights into the advantages and limitations of actuators. Ideal for students of Interfacing for Mechatronic Systems.