This Letter presents a flexible wire-driven linear actuator using a bio-inspired sealing method that allows to replace a rigid rod by a flexible one and reduce the size of a robot link containing ...pneumatic or hydraulic linear actuators. Conventional pneumatic or hydraulic linear actuator sealing hinders the use of flexible wires as actuator rods. In contrast, the proposed tube sealing resembles a long balloon wrapping around the wire and stretching or contracting with the wire rod motion. Therefore, the wire is separated from the chamber and prevents fluid leakage through the flexible wire rod. This sealing method is inspired by earthworm which has slippery skin and stretching or contracting motion. The authors fabricated a prototype wire rod pneumatic linear actuator using the proposed tube seal and conducted leakage tests. In addition, the authors evaluated linearity between the input pressure and output force to determine the linear actuator performance.
Actuation of Mobile Microbots: A Review Hussein, Hussein; Damdam, Asrar; Ren, Liangjie ...
Advanced intelligent systems,
09/2023, Letnik:
5, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Maturation of robotics research and advances in the miniaturization of machines have contributed to the development of microbots and enabled new technological possibilities and applications. ...Microbots have a wide range of applications, including the navigation of confined spaces, environmental monitoring, micro‐assembly and manipulation of small objects, and in vivo micro‐surgeries and drug delivery. Actuators are among the most critical components that define the performance of robots. A comprehensive review of the actuation mechanisms that have been employed in mobile microbots is provided, including piezoelectric, magnetic, electrostatic, thermal, acoustic, biological, chemical, and optical actuation, with a focus on the most recent development and methodologies.
•We introduce the piezoelectric actuators with long working stroke in recent years.•The pros and cons for actuators and the transformation relationships are discussed.•The clamping mechanisms are ...classified into intermittent type and continuous type.
The development of piezoelectric actuation, starting from single-layer materials with the converse piezoelectric effect, then progressing to multilayer piezo-stack actuators, amplified actuators, non-resonant stepping actuators, and resonant ultrasonic actuators, researchers have been developing methodologies to expand the output displacement of the piezoelectric materials. With these developments, the working stroke of the piezoelectric actuators has been increased from the micrometer-scale to the millimeter-scale, then to the centimeter-scale, or even without limit. There are both obvious distinctions and close connections among these approaches. In this paper, we summarize and classify these approaches systematically. Centering around the long working stroke, we not only discuss the pros and cons for each type, but also explore the derivative relations among these principles. Particularly the stepping actuators, by replacing the clamping mechanism, the inchworm actuator, seal actuator and inertial actuator can transform into each other. The structure of this paper aids in understanding the piezoelectric actuators clearly. Moreover, this paper is also beneficial for determining suitable designs, applicable fields and potential directions for future breakthroughs in technology.
Muscles in animals and actuation systems in advanced robots consist not of the actuation component alone; the motive, dissipative, and proprioceptive components exist in a complete set to achieve ...versatile and precise manipulation tasks. We present such a system as a linear electrostatic actuator package incorporated with sensing and braking components. Our modular actuator design is composed of these actuator films and a dielectric fluid, and we examine the performance of the proposed system both theoretically and experimentally. In addition, we introduce a mechanism of optical proprioceptive sensing utilizing the Moiré pattern innately generated on the actuator surface, which allows high-resolution reading of the position of the actuator without noise. The optical sensor is also capable of measuring the force exerted by the actuator. Lastly, we add an electroadhesive brake in the package in parallel with the actuator, introducing a method of mode switching that utilizes all three components and presenting control demonstrations with a robot arm. Our actuation system is compact and flexible and can be easily integrated with various robotic applications.
Reducing moving mass and effective inertia is essential for achieving safe human–robot collaboration. This can be achieved either by employing remote actuation, which moves the mass of actuators away ...from the moving elements of the robot, or by elastic actuation, which decouples the inertia of the actuator from the inertia of the robot’s link. Flexible shafts, being torsionally compliant slender long shafts, offer a combination of remote and series elastic actuation over an obstacle. Modeling such transmission is complicated due to its three-dimensional deformation in torsion, bending, and helical buckling. This paper proposes an algorithm for estimating the polar moment of inertia and stiffness of the flexible shafts using their physical dimensions of length and diameter. Using an inertia-spring–damper model, the stiffness parameters are estimated experimentally for nine flexible shafts with variable diameters and lengths in straight and bent configurations. The proposed algorithm is validated with experimental stiffness values for variable diameters and lengths in straight configuration. For bent configuration, an empirical formulation is provided to incorporate the bending deformation effect till a bending angle of 45∘.
•Flexible shafts act as remote and elastic transmission for robotics.•Algorithm devised to estimate Flexible Shafts’ stiffness and polar moment inertia.•Inertial spring–damper model is used to understand the behavior of flexible shafts.•Stiffness Change by bending flexible shafts is estimated as an empirical formula.
This study proposes a high-speed permanent magnet actuator (HSPMA) for high-voltage vacuum circuit breaker (VCB). The HSPMA comprises mainly of an eddy current repulsion force actuator and a ...permanent magnet (PM) actuator. The structural saliency of HSPMA is described and its control principle is elaborated in details. Finite element method is used and the eddy current is included in the computation of the electro-magnet fields of the HSPMA. The system equations, which couples the magnet field to circuit and mechanical equations, are built in ANSOFT Maxwell and Circuit Editor in this study of the making and breaking procedures of the HSPMA. The simulated characteristics show the design meets the requirement of the high-voltage VCB. The optimal thickness of the eddy current plate is 10 mm. The capacitor also has an economic optimal value of 10,000 µF. The simulated results indicate that the HSPMA has a sound characteristic when compared with circuit breakers with only PM actuator.
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