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Prototyping of automated systems
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
An actuator is a device that performs a mechanical action in response to an input signal. There are three general types of actuators to choose from when creating an automated process: electric, hydraulic, and pneumatic. A major advantage of using these types of actuators is that they are used so much that they are considered reliable in creating an automated process. Each type of actuator has its advantages and disadvantages for each possible application. The key to properly selecting an actuator is to understand the advantages and limitations of each class, and within that class, the subclasses of actuators. For example, when a motor is required to rotate a mechanism, at an accuracy of 0.28, it would allow the use of several different types of motors. An added requirement to this operation that the motor be able to rotate at 2,000 rpm eliminates the selection of the stepper motor subclass. The need to index with precision eliminates the standard electric motor. The subclass of servomotors would be best suited to this operation. The specific motor that is chosen would be dependent on loads, acceleration rates, torque requirements, etc. Such restrictions and selections exist for all major and minor classes of actuators, and being able to select the appropriate actuator requires the understanding of these traits and characteristics.
Adjustment Mechanisms
Published in Anees Ahmad, Handbook of Optomechanical Engineering, 2018
The choice of a suitable actuator for a linear mechanism depends on travel speed, range, resolution, and frequency of adjustment, and cost, size, and weight requirements for the adjustment mechanism. For example, the motorized actuators are generally used for making frequent adjustments in real time. These include DC, linear, and stepper motors and piezoelectric devices. The main advantages of such actuators are long travel range, high resolution and velocity, and position readout capability. These actuators usually come with built-in position encoders and can be used in a closed loop control system. Therefore, the position of an optical component can be monitored, and the drifts due to environmental effects can be corrected in real time. The principle disadvantages of motorized actuators are their high cost and weight and large size.
Hardware Components for Automation and Process Control
Published in Stamatios Manesis, George Nikolakopoulos, Introduction to Industrial Automation, 2018
Stamatios Manesis, George Nikolakopoulos
An actuator is a device that uses some type of energy and produces the required force, either providing motion to an object or actuating something. Actuators (independently of their shape, form, and size) produce the mechanical movements required in any physical process in a factory. It should be highlighted that in any industrial production line, if the actuators are removed, what will remain are only the “passive” metallic and plastic components, while the whole automation will lose its ability to alter or produce something meaningful. All actuators are controllable devices for performing the desired manufacturing operations, in order to have a well-controlled and automated production process. In general, there are various kinds of actuators that can be categorized based on the operation principle, such as thermal, electric, hydraulic, pneumatic, and micro-electro-mechanical (MEMS) ones. Figure 2.1 illustrates a number of different types of actuators.
Technologies used in responsive facade systems: a comparative study
Published in Intelligent Buildings International, 2022
Negar Heidari Matin, Ali Eydgahi
An actuator is a device that converts input energy in the form of a signal into a mechanical or chemical action (Addington and Schodek 2004). Actuators provide motion in facade system with changes in the facade physical properties, directions, magnitude, and application point of forces (Decker 2013; Moloney, Globa, and Wang 2017; Decker and Zarzycki 2013). Actuators utilize external forces to make translational, rotational or combined movements in facade mechanisms (Schumacher, Schaeffer, and Vogt 2010). Translational mechanism performs a bi-dimensional change of shape known as linear motion while rotational mechanism performs a tri-dimensional change of shape that performs swivel motion both in the same axis and/or around a different axis (Al Dakheel and Tabet Aoul 2017). These mechanisms present retracting, folding, expanding (inflating and deflating), sliding, and transforming motions in responsive facades (Sharaidin; Moloney 2009). Different mechanisms can be utilized to provide specific types of motions for an actuator. Actuators can be integrated with specific types of materials and structures in facade systems.
Using conductive fabrics as inflation sensors for pneumatic artificial muscles
Published in Advanced Robotics, 2021
Arne Hitzmann, Yanlin Wang, Tyler Kessler, Koh Hosoda
In this paper, we showed a novel design of an inflation sensor for PAMs. Throughout this paper, we showed that using off-the-shelf components can be used to create a responsive soft sensor. This soft nature is also its most significant disadvantage, as it is hard to generate absolute feedback for the current length of the actuator. As a result, we see the applications of this type of sensor in the area of soft robotics, where precision can be substituted by adaptability. In this area, musculoskeletal robots utilizing PAMs can benefit from our design. Firstly, it is easy to recreate and can also be retrofitted to existing PAMs, due to its external deployment. Secondly, its small size and low footprint on the PAM allow it to be placed in complex musculoskeletal systems, in which actuators can be routed in close proximity. Our evaluations demonstrate that our design provides repeatable results while being simple in design. Compared to earlier solutions, which we listed in the introduction, our design is smaller in dimension than previous external sensors. With this design, we hope to foster the research in musculoskeletal systems by offering an easy entry-point for non-pressure-based control attempts.
Temperature dependence on ferroelectric properties and strain performance of PLZT ceramics containing 9 mol% La
Published in Phase Transitions, 2020
Narit Funsueb, Apichart Limpichaipanit, Athipong Ngamjarurojana
The factors used to determine the performance of actuators are materials, electromechanical coupling (k33), fatigue resistance, operation temperature range and piezoelectric coefficient (d33). The S-E curves are related to maximum strain (Smax) and maximum electric field (Emax) where piezoelectric constant (d*33) is a ratio of maximum strain to maximum electric field (Smax/Emax) [3, 6]. Efficiency of total strain as a ratio of Smax at room temperature and Smax at various temperatures. Squareness of hysteresis (Rsq) is calculated by where Pr is remnant polarization, Ps is saturate polarization and P1.1EC is polarization at 1.1EC [6]. In this part, strain performance and polarization will be explained by S-E, P-E and d*33 at various temperatures divided in five ranges according to the composition.