 working as assistant professor in Department of Mechanical Engineering, Walshian Institute of Technology, Solapur. Today, we are going to learn about actuators. What is actuator and what are different types of actuators? Let's start learning outcome. At the end of this session, learner will be able to identify various types of actuators. So these are the content which we are going to study today. That is what is actuator, types of actuators, features of actuators, hydraulic actuators, pneumatic actuators, electric actuators, thermal and magnetic actuators, and lastly, mechanical actuators. So what is actuator? Let us see what is actuator. An actuator is a component of a machine or a system that moves or controls the mechanism or a system. An actuator is something that converts energy into motion. An actuator is a mechanism by which a control system acts upon an environment. An actuator requires a control signal and a source of energy. A control system can be mechanical or electronic system, software-based, human or a robot. So these are the examples of actuators. They are solenoids, electric motors, hydraulic and pneumatic cylinders and motors. So we have seen what is an actuator here. So let's now think. I just want you to pause the video for a few seconds and just list down the various actuators that you come across in your day-to-day life, different types of actuators that is pneumatic, electrical, hydraulic, mechanical, thermal or magnetic. So I want you to list down the actuators that you come across in your day-to-day life. So let's see. So the first type of actuators are nothing but electrical actuators. In electrical actuators, there are subtypes that is first is DC motors, AC motors, stepper motors, solenoids, relays. And the second is hydraulic actuators. They use hydraulic fuel as a driving force and the third is pneumatic actuators. They use compressed air as a driving force. So these are the actuators that we come across in our day-to-day life. We are going to learn about these actuators in detail further. So before knowing about the actuators, so let's see the function of actuators. The first function of actuators is to provide thrust and positioning in machines used for production or testing. The second one is to control flow rate or to control flow rate of a fluid by positioning the control valves. The third function is to provide support for valve accessories, example, limit switches or solenoid valves. So first is let's see the hydraulic actuators. Hydraulic actuators consist of a cylinder or fluid, motor that uses hydraulic power to facilitate mechanical operation. The mechanical motion is converted to linear rotary or oscillatory motion. Figure shows the schematic diagram of hydraulic actuators. You can see the fluid is placed over here, piston is used to compress the fluid and in this way the actuation occurs. Second one is pneumatic actuators. As we have seen, pneumatic actuators used compressed air as a driving force. Pneumatic means air-based. A pneumatic actuator basically converts the energy formed by vacuum or compressed air at high pressure into either linear or rotary motion. The pneumatic actuators are used for valve controls of water pipes. Pneumatic energy quickly responds to starting and stopping signals. In pneumatic actuators, they produce large forces by relatively small pressure change. For example, the pneumatic brakes can be very responsive to small changes in pressure that are applied by the driver. The figure shows the pneumatic actuator in which the air is used as a driving force or pneumatic that is air-based actuator, compressed air is used as a driving force. Next one is electric actuator. Electric actuators is generally powered by a motor that converts electrical energy into mechanical torque. The electrical energy is used to actuate the equipment such as the solenoid valve which controls the flow of water in the pipes in response to electric signals. Here the figure shows the electric actuator that is various types of actuators, electric actuators you can see here in the figure. The next type of actuator is nothing but thermal actuator. Thermal or magnetic actuator can be actuated by applying thermal or magnetic energy. They are very compact, lightweight, economical and with high power density. These actuators use shape memory materials that is SMMS or shape memory alloys that is SMAS or magnetic shape memory alloys. So here the figure shows this figure shows thermal actuators, various thermal actuators placed over here and this figure shows the magnetic actuator that is micro-motion magnetic actuators or nano-magnetic actuators shown over here. So the next type of actuator is mechanical actuators. The name itself indicates the activation purpose. The mechanical force is required to set the system into the motion. Mechanical actuators converts rotary motion into linear motion. Mechanical actuators involves pinions, gears, rails, pulleys, chains and other devices to operate. Rack and pinion is an example of mechanical actuator. Cranche shaft is another example of mechanical actuator. So these are the example of mechanical that is just we have seen. Rack and pinion is an example of mechanical actuator. So this is the mechanical actuator. Here the rotary motion is converted into linear motion and this figure also shows the mechanical actuators. Here the mechanical equipments are involved to produce the mechanical activation process. Let's see the electric motors. Electric motors usually have a small rating from few horsepower. They are used in small appliances, battery operated vehicles and for medical purpose. Electric motors are also used in toys and in automobiles as auxiliary motors for the purpose of seat adjustment, power windows, sunroof mirror adjustments, blower motors and engine cooling fans. So let's see the DC motors. In DC motors the stator is a set of fixed permanent magnets creating fixed magnetic field while the rotor carries a current. Through brushes and commutators the direction of current is changed continuously causing the rotor to rotate continuously. Let's see the AC motors. These are similar to DC motors except that the rotor is permanent magnet, stator houses, the windings and all the commutators and brushes are eliminated. So this figure shows the DC motor whereas this is the AC motor. In this set of permanent magnets and fixed magnetic field and the rotor carries a current whereas in this the rotor is permanent magnet. So these are the references W Bolton book Shetty and Colt mechatronic system design and a book principle concepts and applications by Tata McGraw-Hills. Thank you.