Electromechanical actuators are becoming an increasingly popular alternative to traditional hydraulic actuators for ship, aircraft, vehicle suspension, robotic, and other applications. These actuators generally include an electric motor, gear train, bearings, shafts, sensors, seals, and a controller integrated into a single housing. This integration provides the advantages of a single shaft, fewer bearings, and ultimately, reduced weight and volume. Research has shown that the motor and gear train are the most critical, performance-limiting components in an actuator, and balancing the performance parameters (torque, weight, inertia, torque density, and responsiveness) among them is not trivial. The Robotics Research Group currently addresses this task by using intuitive rules of thumb and the designers’ experience, and this often requires multiple design iterations between the motor and gear train. In this regard, this research will provide preliminary guidelines for choosing the gear ratios and relative sizes of the motor and gear train when integrating a switched reluctance motor (SRM) with three different gear trains (hypocyclic gear train (HGT), star gear train coupled with a parallel eccentric gear train (Star+PEGT), and star compound gear train coupled with a parallel eccentric gear train (Star Compound+PEGT)) in the preliminary design stage. Research has also shown that there are cost benefits to developing actuator product families to meet the needs of a particular application domain. In this regard, scaling rules for the SRM, HGT, PEGT, and integrated actuators built from them (with diameters ranging from 6 to 50 inches and gear ratios from 100 to 450) will be developed. These scaling rules describe how the performance parameters vary as the size (diameter and aspect ratio) is varied and are useful for quickly sizing motor, gear train, and actuator designs. These scaling rules are useful for two purposes: 1) learning the relationships between the performance and dominant design parameters and 2) obtaining intermediate sizes not previously considered. The rules will be simple enough for designers to learn and use to make intelligent design parameter choices (purpose 1) but will also have sufficient accuracy for obtaining intermediate designs (purpose 2). The scaling rules are summarized in a series of three-dimensional design maps, with an emphasis on the development of visual decision-making tools. This research also formulates an actuator design procedure that incorporates the two central concepts of this research, balancing parameters and scaling, and this procedure is embedded within computational (MatLab) and solid modeling (SolidWorks) software programs. In addition to developing rules for scaling and balancing parameters, the procedure was also used for the following purposes. First, direct drive and geared actuators were compared in terms of their torque density and responsiveness to determine which alternative is superior for different gear ratio, diameter, and load inertia combinations. Second, alternative minimum sets of actuators were developed for an illustrative application, and the anticipated performance losses due to using common parameters among the sets were quantified. / text

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This thesis concerns the design, construction, control, and testing of soft robotic actuators to be used in a soft robotic exoskeleton; the Boa Exoskeleton could be used for joint rehabilitation including: wrist, elbow and possibly shoulder or any joint that requires a soft body actuator to aid with bending movement. We detail the design, modeling and fabrication of two types of actuators: Fiber-reinforced Actuator and PneuNet Actuator. Fiber-Reinforced actuator was chosen for the exoskeleton due to its higher force. The Fiber-Reinforced actuator molds were 3D printed, four models were made. Two materials were used to fabricate the models: Dragon Skin 30A and Sort-A-Clear 40A. Two number of windings: (n=40) and (n=25), actuators wrapped with carbon fiber. An air tank was used to supply pressure. The actuators were studied at different pressures. Pressure-force relation was studied, and a close to linear relationship was found. Boa Exoskeleton was made for wrist. Electromyography (EMG) was used; Four EMG receptors were put around the arm. EMG was utilized to actuate the Boa Exoskeleton and record the muscle movement. Five tests were done on six human subjects to validate the Boa Exoskeleton. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

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University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

Traditional robots are made from hard materials like hard plastic or metal and consist of regular rigid mechanical parts. Using those parts has some limitations, like limited dexterity and lack of flexibility. Some of these limitations could be avoided through using a compliant material, because it has higher flexibility and dexterity. It is also safer to be in direct contact with humans. This thesis studies soft pneumatic manipulators (SPMs) that move in multi degrees of freedom (MDOF), which makes them able to perform various functions. The study will include designing, fabricating, and testing three different SPMs with different taper angles -- 0^0, 1^0, and 2^0 -- to measure the effect of varying this geometry on the achievable force by the end effector and the range of bending and elongation. Every single SPM consists of three soft pneumatic chambers to reach unlimited points on its workspace through implementing bending and elongating movements. There are a lot of applications for this kind of soft actuators, like rehabilitation, underwater utilizes, and robots for surgery and rescues. Most soft pneumatic actuators provide one kind of movement, for bending, twisting, or elongating. Combining more than one kind of movement in one soft pneumatic actuator provides considerable contributions to the body of research. The SPMs were controlled and tested to evaluate the achieved force and two kinds of movement, bending and elongating range. The results of each module has been compared with the others to determine which actuator has the best performance. Then a force controller was created to maintain the desired force that was achieved by the end effector. The results indicated that the optimal angle of the SPM was 2^0. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

In this research, a novel magnetorheological (MR) fluids based multifunctional actuator for assistive knee braces is designed. To decrease the dimension of the actuation device while enhancing its perfonnances, a motor and MR fluids are integrated into a single device. With MR fluids, the actuator possesses multiple functions as motor, clutch, and brake while meeting the requirement of nonnal human motion as well. In this thesis, design details and operating principle of the actuator are illustrated, and possible configurations of the motor part and clutch/brake part are discussed. Finite element method is utilized to analyze the magnetic circuits, influence of pennanent magnet on MR fluids, and magnetic flux distribution. Different clutch/brake parts with various inner coils are compared and analyzed, followed by a design optimization to improve the output torque. Prototypes of the multifunctional actuator are fabricated and tested, and characteristics of each function are investigated. As the actuator has multiple functions, modeling is developed for different functions, and system identification is carried out to determine the parameters. Adaptive control is utilized to control the actuator for torque and speed tracking. A smart joint using such a multifunctional actuator is designed, and its prototype is fabricated and tested. Power consumptions of knee brace using the smart joint are investigated during normal walking cycle. The results show that the developed actuator and smart joint are promising to be used in assistive knee braces. / Guo, Hongtao. / Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 154-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

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In this thesis, the development of a novel electro-thermally actuated bi-stable out-of-plane two way actuated buckled micro-bridge for a potential application in optical switching is presented. The actuator consists of a bridge supported by 'legs' and springs at its four corners. The springs and the bridge are made of a tri-layer structure comprising of 2.5??m thick low-stress PECVD oxide, 1??m thick high-stress PECVD oxide and 2??m thick heavily phosphorus doped silicon. The legs, on the other hand, are 2??m thick single layer heavily phosphorus doped silicon. Both legs and springs provide elastically constrained boundary conditions at the supporting ends, without of which important features of the micro-bridge actuator could not have been achieved. This microbridge actuator is designed, simulated using ANSYS, fabricated and tested. The results from the testing have shown a good agreement with analytical prediction and ANSYS simulation. The actuator demonstrated bi-stability, two-way actuation and 31??m out-of-plane movement between the two-states using low voltage drive. Buckled shape model, design method for bi-stability and thermo-mechanical model are developed and employed in the design of the micro-bridge. These models are compared with Finite Element (FE) based ANSYS simulation and measurements from the fabricated micro-bridge and have shown a good agreement. In order to demonstrate the potential application of this actuator to optical switching, ANSYS simulation studies have been performed on a micro-mirror integrated with the micro-bridge actuator. From these studies, the optimum micro-mirror size that is appropriate for the integration has been obtained. This optimal mirror size ensures the important features of the actuator. Mirror fabrication experiments in (110) wafer have been carried out to find out the appropriate compensation mask size for a given etch depth and the suitable wafer thickness that can be used to fabricate the integrated system.