Actuator
An actuator is a device that converts energy into motion. It is commonly used in various engineering applications to control or move mechanical systems, such as valves, pumps, and motors. Actuators can be powered by electric, hydraulic, pneumatic, or mechanical means, and they play a crucial role in enabling automated and controlled movements in technology and engineering systems.
7 Key excerpts on "Actuator"
- Ian C. Turner(Author)
- 2020(Publication Date)
- Routledge(Publisher)
...Chapter 8 Actuators Aims At the end of this chapter you should be able to: Appreciate the distinction between linear and rotary motion Actuators. Understand the principle of operation of various linear motion Actuator devices. Recognise the various graphical symbols used for linear motion Actuators. Understand the principle of operation of various rotary motion Actuator devices. Recognise the various graphical symbols used for rotary motion Actuators. Be aware of the various methods of visual indication of actuation. 8.1 Types of Actuators An Actuator is an output device for the conversion of supply energy into useful work. The output signal is controlled by the control system, and the Actuator responds to the control signals via the final control element. There are, of course other types of output device whose function is to indicate the status of control systems or actuation. The fluid power Actuator can be described under two groups: linear or rotary: linear motion single-acting cylinders double-acting cylinders rotary motion air motor and hydraulic motor rotary Actuator. 8.2 Single-acting cylinder With single-acting cylinders, fluid is applied on only one side of the piston face. The other side is open to atmosphere. The cylinder can produce work in only one direction. The return movement of the piston is effected by a built-in spring or by the application of an external force. The spring force of the built-in spring is designed to return the piston to its start position with a reasonably high speed under no load conditions. The single-acting cylinder (Figure 8.1) has a single piston seal which is fitted to the fluid power supply side. The exhaust air on the piston rod side of the cylinder is vented to atmosphere through an exhaust port. If this port is not protected by a gauze cover or filter, then it is possible that the entry of dirt particles may damage internal seals...
eBook - ePubActuators and Their Applications
Fundamentals, Principles, Materials, and Emerging Technologies
- Rajender Boddula, Abdullah M. Asiri, Rajender Boddula, Abdullah M. Asiri(Authors)
- 2020(Publication Date)
- Wiley-Scrivener(Publisher)
...The mechanical motion gives an output in terms of linear, rotary, or oscillatory motion. Hydraulic actuating system consists of sensors, controller, and actuating components [ 8 ]. This system can handle heavy load with less input. The main parts of the hydraulic Actuator include: Control device (controls whole actuating system by providing signals), Valve (regulates direction, fluid flow rate, and pressure), Pump (pressurizes fluid to required level), Sensors (supplies feedback signal), reservoir, Pipes, filter and accumulator. Figure 3.5 Pneumatic actuation: (a) Pneumatic Cylinder; (b) A pick-and-place pneumatic system [ 6 ]. Electromechanical Actuators: they change electrical into mechanical energy. It possesses high response speed, can be maintained and controlled easily, low cost, and a clean energy source though it is susceptible to mechanical failure due to moving parts. A very good example of this type of Actuators is electric motor (which can be DC motors, AC motors, and stepper motors). Mechanical Actuators: this kind of Actuator aids the transformation of motion into other forms using pulleys, belts, gears, chains, or rigid links. Belts and chains transmit torque from one pulley to another pulley at a specific distance; gears are used to transform rotary motion to another where torque variation is required. They are difficult to implement in complex motion condition. 3.5 Actuator Components Actuator components can be grouped into three headings, namely, hydraulics, pneumatics, and electric motors. 3.5.1 Hydraulics and Pneumatics The two have similar components only that hydraulic Actuators use liquid as driving force while pneumatic Actuators make use of air as driving force. They are otherwise known as mechanical Actuators. The most important components include regulators, Actuator cylinder, speed valves, solenoid valve, reservoir, and hand valve. They are discussed below. Regulators Regulators are devices used to control circuit pressure...
eBook - ePub- Maksym Spiryagin, Stefano Bruni, Christopher Bosomworth, Peter Wolfs, Colin Cole(Authors)
- 2021(Publication Date)
- CRC Press(Publisher)
...5 Actuators DOI: 10.1201/9781003028994-5 5.1 INTRODUCTION Actuators and sensors are a fundamental component of mechatronic systems. Actuators are used to drive the mechatronic system according to a control action elaborated by the controller which can be either a specified movement (position control, speed control) or a force or torque (force control). Sensors instead provide the controller with measured signals describing the state of the system being controlled (the plant), enabling the implementation of feedback control strategies, see Chapter 4. It should be noted that Actuators themselves are feedback-controlled systems, so in a mechatronic railway vehicle there are usually multiple feedback control loops nested one into another. Actuators are typically complex devices involving the use of power made available in some form (e.g., electrical power from batteries, fluid power from pressurized air or oil) which is transformed to mechanical power and used to apply the control action to the plant. Therefore, the use of Actuators involves significant additional complexity in a railway vehicle, although it is recognized that active control may result in substantial simplifications of the vehicle's mechanical structure [1]. Different types of Actuators are suitable for mechatronic railway vehicles and the choice of the principle of actuation impacts significantly on the overall design of the vehicle. It is one main aim of this chapter to present the different principles of actuation that can be used in mechatronic railway vehicles, outlining their advantages and drawbacks. For instance, electro-mechanical Actuators are fast, relatively compact, and do not require the use of fluid, but some of their failure modes, particularly jamming due to a failure in the mechanical transmission, may lead to safety issues...
eBook - ePubHydraulics and Pneumatics
A Technician's and Engineer's Guide
- Andrew Parr(Author)
- 2011(Publication Date)
- Butterworth-Heinemann(Publisher)
...Chapter | five. Actuators A hydraulic or pneumatic system is generally concerned with moving, gripping or applying force to an object. Devices which actually achieve this objective are called Actuators, and can be split into three basic types. Linear Actuators, as the name implies, are used to move an object or apply a force in a straight line. Rotary Actuators are the hydraulic and pneumatic equivalent of an electric motor. This chapter discusses linear and rotary Actuators. The third type of Actuator is used to operate flow control valves for process control of gases, liquids or steam. These Actuators are generally pneumatically operated and are discussed with process control pneumatics in Chapter 7. Linear Actuators The basic linear Actuator is the cylinder, or ram, shown in schematic form in Figure 5.1. Practical constructional details are discussed later. The cylinder in Figure 5.1 consists of a piston, radius R, moving in a bore. The piston is connected to a rod of radius r which drives the load. Obviously if pressure is applied to port X (with port Y venting) the piston extends. Similarly, if pressure is applied to port Y (with port X venting), the piston retracts. Figure 5.1 A simple cylinder The force applied by a piston depends on both the area and the applied pressure. For the extend stroke, area A is given by πR 2. For a pressure P applied to port X, the extend force available is: (5.1) The units of expression 5.1 depend on the system being used. If SI units are used, the force is in newtons. Expression 5.1 gives the maximum achievable force obtained with the cylinder in a stalled condition. One example of this occurs where an object is to be gripped or shaped. In Figure 5.2 an object of mass M is lifted at constant speed. Because the object is not accelerating, the upward force is equal to Mg newtons (in SI units), which from expression 5.1 gives the pressure in the cylinder...
eBook - ePubMechatronics
An Introduction
- Robert H. Bishop, Robert H. Bishop(Authors)
- 2017(Publication Date)
- CRC Press(Publisher)
...Use of sinusoidal inputs is the most simple and reliable way of dynamic calibration. However, if generating sinusoidal input becomes impractical (for example, temperature signals) then a step input can substitute for the sinusoidal signal. The transient behavior of step response should yield sufficient information about the dynamic response of the sensor. 9.2 Actuators Actuators are basically the muscle behind a mechatronics system that accepts a control command (mostly in the form of an electrical signal) and produces a change in the physical system by generating force, motion, heat, flow, etc. Normally, the Actuators are used in conjunction with the power supply and a coupling mechanism as shown in Figure 9.7. The power unit provides either AC or DC power at the rated voltage and current. The coupling mechanism acts as the interface between the Actuator and the physical system. Typical mechanisms include rack and pinion, gear drive, belt drive, lead screw and nut, piston, and linkages. Classification Actuators can be classified based on the type of energy as listed in Table 9.2. The table, although not exhaustive, lists all the basic types. They are essentially of electrical, electromechanical, electromagnetic, hydraulic, or pneumatic type. The new generations of Actuators include smart material Actuators, micro- Actuators, and NanoActuators. Actuators can also be classified as binary and continuous based on the number of stable-state outputs. A relay with two stable states is a good example of a binary Actuator. Similarly, a stepper motor is a good example of continuous Actuator. When used for a position control, the stepper motor can provide stable outputs with very small incremental motion. Principle of Operation Electrical Actuators Electrical switches are the choice of Actuators for most of the on-off type control action...
eBook - ePub- Alan Hendrickson(Author)
- 2012(Publication Date)
- Routledge(Publisher)
...14 Actuators DOI: 10.4324/9780080557540-14 Electric, Hydraulic or Pneumatic Mechanical effects may be powered by one of several types of Actuators. The vast majority of machines use either electric motors or fluid power cylinders (either hydraulic or pneumatic), and so these two basic types will be the primary focus of this chapter. The selection process involves first choosing whether a motor or cylinder is most appropriate for the given application and then determining the sizing and configuration of the individual Actuator. The advantages of each will be covered in the sections which follow, as well as the process used to select the appropriate Actuator. Powering the Actuator All Actuators require an external power input. Electric motors require a motor starter to control them, or if variable speed is required, an appropriate motor drive is necessary to provide speed control and full torque throughout the speed range. Hydraulic Actuators need a hydraulic power unit to provide the required pressure and flow, and valves to control the speed and direction of the oil. Pneumatic Actuators require a compressor (generally already present in any shop likely to attempt to build stage machinery, but not necessarily available on stage) and valving to control the flow of air. Since discussions of these motor drives and hydraulic or pneumatic controls are beyond the scope of this text, suggested sources for more information are listed at the end of this chapter. Section I: Electric Power Electric Motors Electric motors are the most commonly used power source in theatrical mechanical design, generally being the first choice for deck winches, turntable drives and motorized rigging systems...
eBook - ePubControl of Mechatronic Systems
Model-Driven Design and Implementation Guidelines
- Patrick O. J. Kaltjob(Author)
- 2020(Publication Date)
- Wiley(Publisher)
...Finally, the sensing and operating principles of dynamic sensors such as the dynamics model, time domain, and frequency response characteristics are developed. 8.2 Actuators in Mechatronics Electric Actuators can generate either a binary output signal (i.e. contact relay) or continuous signal (stepper motor). Such electrical-driven actuating systems can be classified based on their electrostatic or electromagnetic – and even electrothermal – design principles. Their coupled transmission elements generate force to motion, pressure to flow, heat, and so on. Recent advances in nanotechnologies have led to the development of low-scale Actuators (nano or micro). Electromechanical Actuators usually operate based on the electrostatic (electrostatic Actuators) or the electromagnetic (electromagnetic Actuators) principle. Electrostatic Actuators use charged particle motion within the induced field to generate adequate force, vibration, pressure, and temperature variation displacement of a membrane or beam. They include piezo-electric Actuators, which deliver strain-based actuation from piezo-materials by generating a voltage proportional to the applied mechanical deformation. Such piezo-materials use either ceramics (i.e. lead-zirconate-titanate) or polymers (i.e. polyvinylidene fluoride). Surrounded by electrodes or attached to them they allow strain-based actuation of up to a few kilovolts per millimeter...
