Actuators sizing

SN Applied Sciences

An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve. The performance of a valve is largely dependent on its actuator. Three factors are important for engineers to consider when selecting an actuator: frequency of operation, ease of access, and critical functions. Valve actuators should perform several functions including moving the valve closure member to an appropriate position, holding the valve closure member in the desired position, providing enough force or torque for seating the closure member and meeting the required shut down leakage class, providing fully open or fully close or failure mode as is, or providing a certain amount of closure member rotation with the right speed. In general, actuator can be hydraulic, pneumatic or electrical. This paper discusses the mechanism plus advantages and disadvantages of these three types of actuators. Affected parameters for actuator selection include the availability of a power source, torque and size of the valve, failure mode, speed of operation, frequency and ease of operation, control accessories, hazardous area, and cost. This paper presents a case study of breakaway torque (break to open) calculation and actuator sizing for a full-bore ball valve in pressure Class 300 equal to 50 barg nominal pressure and 22Cr duplex body material. The valve is fail close with an emergency shut down function, and a pneumatic actuator was selected for the valve. Fail close means that the valve will close in case of losing the power used as a source of actuator operation. Other four torque values were provided from the valve supplier. The calculated breakaway valve force and torque were used as a basis for actuator air cylinder sizing assuming air pressure of 7 barg and system efficiency of 90%. Force and torque for closing the valve were used to calculate the spring movement as well as spring piston length through Hook's law.

This paper deals with the preliminary design of electromechanical actuators at the architecture stage, aiming at providing means to compare candidate solutions. The preliminary design requires the sizing of various components (e.g. mechanical reducers, brushless motor, speed controller). A power sizing approach based on scaling laws that can be numerically implemented into a simple design model is described. The proposed approach is illustrated through examples of nose landing gear architectures.

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1997

A method is presented for selecting the type of actuator best suited to a given task, in the early stages of engineering design. The selection is based on matching performance characteristics of the actuator, such as force and displacement, to the requirements of the given task. The performance characteristics are estimated from manufacturers' data and from simple models of performance limitation such as heat generation and resonance. Characteristics are presented in a graphical form which allows for a direct and systematic comparison of widely different systems of actuation. The actuators considered include man-made actuators (such as hydraulic, solenoid and shape memory alloy) and naturally occurring actuators (such as the muscles of animals and plants).

Advanced Engineering Materials, 2002

Actuators are controllable work-producing devices. They come in many shapes and forms. A strategy for selecting actuators to meet specified design requirements is described here. A number of considerations enter: the type and characteristics of the actuator, the nature of the power-source (the COMMUNICATIONS

The main engine of the ship is a complex technical object, which provides propulsion of the screw and ensures the safety of a ship at sea. It consists of a number of control systems such as lube oil temperature control, temperature control of the cooling water, fuel viscosity control or adjustable speed control of the main engine. Each of the main propulsion control system affects the safety of the ship. Continuous automation systems are built with standard transducer of measured quantity, the controller and actuator. The actuator is responsible for the direct setting of the size of the control object. The actuator is connected to the control valve and the actuator position change translates into a change in the flow rate of the working medium. Thus, the operating element is required to operate in the linear characteristics of the standard signal range. From the other hand, the control valve provides flow characteristics linear or of equal percentage. This control principle of medium flow is used in various control systems. The actuator of the control valve is always equipped with a positioner, which corrects errors in the position of the valve relative to the input signal. The presented design of the motorized valve is an analog system. Using the technique of converting multiple digital signal causes the system complexity and predisposition to damage. Eliminating the intermediate elements can improve the quality control and system safety. Then it is beneficial to have a design of the operating element based on the direct digital processing unit. The aim of paper has been to present design of the valve actuator, which completely abandons the digital-to-analogue convertor. The new design should increase the level of security of the system and quality control. The design layout is presented in the article. The new actuator is on-off valves, which control, directly from the digital bits, the form of the output signal. The control signal may use the control algorithms to be used or developed individually to the actuator design.

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 2012

This paper presents estimation models for the model-based preliminary design of electro-mechanical actuators. Models are developed to generate all the parameters required by a multi-objective design, from a limited number of input parameters. This is achieved by using scaling laws in order to take advantage of their capability to reflect the physical constraints driving the actuator's component sizing. The proposed approach is illustrated with the major components that are involved in aerospace electromechanical actuator design. The established scaling laws provide the designer with parameters needed for integration into the airframe, power sizing, thermal balance, dynamics and reliability. The resulting estimation models are validated with industrial data.

Advanced Robotics, 2003

This article presents two methods for selecting actuators based on the dynamic loading criteria which yield a manipulator with a desired level of dynamic performance. Here, dynamic performance is measured in terms of a robot's acceleration and force capabilities, which describe its ability to accelerate the end-effector and to apply forces to the environment, given the limitations on its actuator torques. The Dynamic Capability Equations are used to model the relationship between actuator torque capacities and the acceleration and force capabilities, because they treat linear and angular quantities in a consistent and physically meaningful way. This article discusses actuator selection for a single con guration, as well as for multiple con gurations.

Aircraft Engineering and Aerospace Technology, 2015

Purpose -Aerospace actuation systems are currently tending to become more electrical and fluid free. Methodologies and models already exist for designing the mechanical and electrical components but the actuator housing design is still sketchy. This paper proposes preliminary design models of actuator housing that enable various geometries to be compared without requiring detailed knowledge of the actuator components.

a guide to help one in selecting a stepper motor

Ieee Robotics Amp Amp Amp Automation Magazine, 2009

I n the growing fields of wearable robotics, rehabilitation robotics, prosthetics, and walking robots, variable stiffness actuators (VSAs) or adjustable compliant actuators are being designed and implemented because of their ability to minimize large forces due to shocks, to safely interact with the user, and their ability to store and release energy in passive elastic elements. This review article describes the state of the art in the design of actuators with adaptable passive compliance. This new type of actuator is not preferred for classical position-controlled applications such as pick and place operations but is preferred in novel robots where safe humanrobot interaction is required or in applications where energy efficiency must be increased by adapting the actuator's resonance frequency. The working principles of the different existing designs are explained and compared. The designs are divided into four groups: equilibrium-controlled stiffness, antagonistic-controlled stiffness, structure-controlled stiffness (SCS), and mechanically controlled stiffness. In classical robotic applications, actuators are preferred to be as stiff as possible to make precise position movements or trajectory tracking control easier (faster systems with high bandwidth). The biological counterpart is the muscle that has superior functional performance and a neuromechanical control system that is much more advanced at adapting and tuning its parameters. The superior power-to-weight ratio, force-toweight ratio, compliance, and control of muscle, when compared with traditional robotic actuators, are the main barriers for the development of machines that can match the motion, safety, and energy efficiency of human or other animals. One of the key differences of these systems is the compliance or springlike behavior found in biological systems [1]. Although such compliant