Linear Actuator Research Articles

Experimental Verification of Linear Oscillatory Actuator with Switchable Degree-of-Freedom Using Electropermanent Magnet

Experimental Verification of Linear Oscillatory Actuator with Switchable Degree-of-Freedom Using Electropermanent Magnet

A study of fine-needle aspiration cytology consisting of a vibrating linear resonant actuator in cases of thyroid nodules

A study of fine-needle aspiration cytology consisting of a vibrating linear resonant actuator in cases of thyroid nodules

A Driving–Clamping Integrated Inchworm Linear Piezoelectric Actuator With Miniaturization and High Thrust Density

A Driving–Clamping Integrated Inchworm Linear Piezoelectric Actuator With Miniaturization and High Thrust Density

Comparing the Perceived Intensity of Vibrotacitle Cues Scaled Based on Inherent Dynamic Range.

Wearable devices increasingly incorporate vibrotactile feedback notifications to users, which are limited by the frequency-dependent response characteristics of the low-cost actuators that they employ. To increase the range and type of information that can be conveyed to users via vibration feedback, it is crucial to understand user perception of vibration cue intensity across the narrow range of frequencies that these actuators operate. In this paper, we quantify user perception of vibration cues conveyed via a linear resonant actuator embedded in a bracelet interface using two psychophysical experiments. We also experimentally determine the frequency response characteristics of the wearable device. We then compare user perceived intensity of vibration cues delivered by the bracelet when the cues undergo frequency-specific amplitude modulation based on user perception compared to modulation based on the experimental or manufacturer-reported characterization of the actuator dynamic response. For applications in which designers rely on user perception of cue amplitudes across frequencies to be equivalent, it is recommended that a perceptual calibration experiment be conducted to determine appropriate modulation factors. For applications in which only relative perceived amplitudes are important, basing amplitude modulation factors on manufacturer data or experimentally determined dynamic response characteristics of the wearable device should be sufficient.

Development of Cylindrical Linear Actuator for Vertical Transfer: Fundamental Consideration of Effect of Shape on Thrust Characteristics

Development of Cylindrical Linear Actuator for Vertical Transfer: Fundamental Consideration of Effect of Shape on Thrust Characteristics

Frequency-Convertible Driving Principle of Low-Frequency Linear Actuation With Double Orthogonal Wafer Oscillators

Frequency-Convertible Driving Principle of Low-Frequency Linear Actuation With Double Orthogonal Wafer Oscillators

Design, Modeling, and Simulation of a Novel Electromagnetic Linear Actuator for Linear Motion

Design, Modeling, and Simulation of a Novel Electromagnetic Linear Actuator for Linear Motion

Design and Characterization of an Efficient Multistable Push-Pull Linear Actuator Using Magnetic Shape Memory Alloys

Design and Characterization of an Efficient Multistable Push-Pull Linear Actuator Using Magnetic Shape Memory Alloys

Linear Actuators for High-Speed Reciprocating Motion with Dual Halbach Arrays (Fundamental Consideration of the Effect of Magnet Arrangement on Thrust Characteristics)

Linear Actuators for High-Speed Reciprocating Motion with Dual Halbach Arrays (Fundamental Consideration of the Effect of Magnet Arrangement on Thrust Characteristics)

Multiscale Topology Optimization for Lightweight Porous Linear Actuation Micro Mechanisms with Enhanced Heat Dissipation Under Laser Activation

Multiscale Topology Optimization for Lightweight Porous Linear Actuation Micro Mechanisms with Enhanced Heat Dissipation Under Laser Activation

An interface design for comparison of energy consumption of penumatic and ball screw-driven linear actuators

Today, engineers use many computer programs and applications to model and analyze engineering problems. However, the demand for user-friendly interfaces and web-based applications is increasing daily to select the appropriate system components according to different working conditions and to evaluate the results comparatively. Also, most of these interfaces calculate the actuators' size and are mostly developed by foreign manufacturers. Nowadays, with the increase in energy costs, the demand for the use of energy-saving products is also increasing. Therefore, examining and comparing the energy consumption of the actuator elements used in the systems depending on the work done is necessary.
 In this study, the authors discussed the issue of developing an interface that can define the appropriate size of actuators for the different operating conditions, such as different loads, slopes, friction, opposite load, and speed, and enable comparative energy consumption according to these elements for electro-pneumatic and servo motor driven ball screw shaft driven actuator types.

Consequent pole flux modulated linear actuator under winding chang and field oriented control driving conditions for long track and multi-track agricultural robot

The electromagnetic performance improvement of a double saliency (DS) flux modulated (FM)- permanent magnet linear synchronous motors (PMLSM) for agricultural robots is proposed in this work by minimizing the effect of cross-coupling. To understand the effect of the cross-coupling on the electromagnetic performance, a dq axes model of the DS FM-PMLSM is developed and analyzed under different driving conditions. Based on the result obtained, winding modification schemes are proposed to minimize the thrust ripple and improve the zero torque control. The modified models are studied using finite element analysis (FEA) and the model with the best performance is selected for prototyping. The prototype is then tested and the results are validated against the electromagnetic performance obtained using the FEA. This research targeted the development of a low-cost linear actuator for a sapling grower gantry robot that can be used by farmers around the world.

Design and development of robotic collaborative system for automated construction of reciprocal frame structures

AbstractRobotic technologies have shown their potential to improve efficiency, precision, and safety for construction tasks. In this paper, the concept of design for robotic construction (DfRC) is introduced, and robotic collaborative systems are developed for the construction of load‐carrying structures. An automated structural assembly was achieved and demonstrated through robotics with a preference for reciprocal frame (RF) structures. Key innovations include the use of magnetic temporary connections to minimize offsets of mobile robots and linear actuators as temporary supports during construction. Furthermore, specific procedures are formulated to navigate the robots and to target and install the components using a fiducial marker system and simultaneous localization and mapping packages, with consideration of structural deformation during construction due to self‐weight. The successful assembly of a 4.5‐m span RF structure demonstrates the potential of DfRC and the proposed robotic collaborative system in the automated construction of load‐carrying structures.

A novel Schönflies-motion generator parallel manipulator with decoupled rotational freedom

This paper introduces a four-legged decoupled Schönflies-motion generator parallel manipulator, free of passive limbs, provided with three linear actuators and one rotary actuator. The displacement analysis problem leads to closed-form solutions, thus avoiding the application of numerical methods for their solution, an unusual feature for most parallel manipulators. Subsequently, the theory of screws allows for solving the velocity, acceleration, and jerk analyses. Canceling the passive joint rates of the limbs is an indisputable advantage of the reciprocal-screw algebra. Moreover, upon the velocity analysis, the singularity analysis of the parallel manipulator is carried out by investigating the nature of the Jacobian matrices of the parallel manipulator. Then, we conclude that the robot at hand is free of type I and III singularities. Numerical examples enhance the correctness of the kinematic analysis method employed in the contribution. As far as the authors are aware, the topology of the parallel manipulator investigated here is original.

Electrochemically Activated Multifunctional Carbon Fibre Composites

A multifunctional lightweight material combines several functions in a single material entity able to simultaneously bear mechanical loads by acting as a carbon fibre composite component while providing one or more other functionalities at the same time, e.g. storing energy. Carbon fibres are particularly attractive as they can be used both as a high-performance structural material and as an active electrochemical material. Carbon fibres allow for ion insertion into their microstructure with capacities comparable to graphite and hard carbon used in state-of-the-art lithium-ion and other alkali-ion batteries [1]. Carbon fibres are electrically conductive and can therefore replace the conventional metallic current collector. Carbon fibres are thus in this context a truly multifunctional material. A piezo-electrochemical transducer effect (PECT) [2], has also been discovered in ion inserted carbon fibres. The PECT-effect, that mechanical load changes the electrochemical potential of ion-inserted materials, could be used for sensing, where a voltage change is related to the mechanical strain in the material. When carbon fibres are inserted with alkali ions, they expand in the axial direction [3]. This expansion could be used for making linear actuators with high forces or even to create shape-morphing materials [4]. Combing the PECT effect with the expansions allow for using carbon fibres in an electrochemical cell to harvest energy [5],[6]. Such functionalities could be combined with an inherent electrochemical energy storage (battery function) capability. Imagine a solid-state high-performance structural material that senses its own state, can change shape and harvest energy – that is stored in the material itself!In this work, we will show functionalities coming from alkali ion insertion in carbon fibres that goes beyond the battery function, and how these functions can be combined in a single device. The starting point for these concepts are so called structural batteries, which are hybrid and multifunctional composite materials able to carry load while storing electrical energy like lithium-ion batteries. In such a battery, carbon fibres are used as the load carrying material thanks to their excellent strength and stiffness properties, but also as the active negative electrode. They also include a multifunctional matrix system – a structural battery electrolyte (SBE), the material holding the fibres together to make a solid-state load carrying material, but which at the same time is ionically conductive and chemically stable in the voltage window used. It also includes a multifunctional positive electrode – a composite electrode based on conventional ion inserting materials like lithium iron phosphate (LFP) supported by electrochemically active carbon fibres for load carrying and electrical conduction. This can then also be used for inherent strain sensing in the material without any added mass or wiring. The material can also be made to shape-morph with electrical control at low voltages and harvesting energy by converting mechanical strain to electrical power.

Development of Mobility Type Upper Limb Power Assist System —Mechanism and Design of Power Assist Device—

In fruit cultivation, viticulture requires the longest working hours in extended arm postures, much of which is carried out in standing postures to accumulate fatigue on arms, shoulders, and legs: a tough working environment. In this study, we propose a power assist system to assist its users in their extended arm work while they move in vineyards. The proposed system largely consists of a mobile robot, a power assist device for work, and a control system. The mobile robot is structured with a tracked vehicle for rough terrain arranged on its left and right sides so that the users can sit between the two vehicles and be assisted by the power assist device for work installed on it. The power assist device for work with a single linear actuator utilizing a linkage mechanism has the function to retain users’ hand attitude angles while assisting the flexion and extension movements of their shoulder, elbow, and carpometacarpal joints. Then, we verify by simulations the effects that the arrangement and lengths of links will have on the carpometacarpal joints’ trajectories as well as on the hand attitude angles. Finally, in order to check the effectiveness of the proposed power assist device for work, we conducted the evaluation experiments for assumed grape-harvesting work and gibberellin treatments. As a result, we proved its work assisting effects from the muscle activity states as well as its applicability to other kinds of work by altering its linkage structure and hand support part.

Research on variable stiffness asymmetrical resonant linear piezoelectric actuator based on multi-modal drive

In this paper, a linear piezoelectric motor with variable stiffness and asymmetric resonance is proposed, which is driven by a single harmonic signal. Working in the resonant state improve the output performance of the motor. Motor control is relatively simple and can realize reverse movement under the driving of second-order single harmonic signal. At the same time, the new motor can obtain different operating speed and step distance by changing the clamping position in front and back to meet the requirements of different loads and different working conditions and has strong applicability. By experiment, the first-order optimal operating frequency of the motor prototype at three different stiffness adjustment positions is 88 Hz, 90 Hz and 92 Hz respectively. Under the excitation of 240 Vp–p first-order resonance signal, the corresponding output speed of the motor prototype is 16.116 mm s−1, 20.457 mm s−1 and 25.015 mm s−1 respectively, and the corresponding displacement resolution is 0.18 mm, 0.22 mm and 0.27 mm respectively. When the stiffness adjustment positions is 2 mm, the maximum load of the motor prototype reaches 450 g. The second-order optimal operating frequency at the stiffness adjustment positions 1 mm is 601 Hz. Under the excitation of a 240 Vp–p second-order resonant signal, the reverse output speed of the motor prototype is 13.126 mm s−1, and the corresponding displacement resolution is 0.02 mm.

Laser-Powered Vibrotactile Rendering

We investigate the feasibility of a vibrotactile device that is both battery-free and electronic-free. Our approach leverages lasers as a wireless power transfer and haptic control mechanism, which can drive small actuators commonly used in AR/VR and mobile applications with DC or AC signals. To validate the feasibility of our method, we developed a proof-of-concept prototype that includes low-cost eccentric rotating mass (ERM) motors and linear resonant actuators (LRAs) connected to photovoltaic (PV) cells. This prototype enabled us to capture laser energy from any distance across a room and analyze the impact of critical parameters on the effectiveness of our approach. Through a user study, testing 16 different vibration patterns rendered using either a single motor or two motors, we demonstrate the effectiveness of our approach in generating vibration patterns of comparable quality to a baseline, which rendered the patterns using a signal generator.

Magnetothermal soft actuators from recycled face mask materials

Polymeric soft actuators offer numerous advantages such as lightweight, compactness, safety and versatility, making them suitable for applications requiring delicate manipulation and adaptability. However, their susceptibility to wear and degradation results in a shorter service life compared to conventional metallic actuators, leading to increased waste generation. To address this issue, this paper presents a sustainable approach to utilising waste materials, specifically repurposing stretchable strings from used disposable facemasks, to create magnetic nanoparticles infused yarn actuators. An innovative infusion technique is presented to aid in the scalable manufacturing of high-volume magnetic yarn actuators. The developed actuators demonstrate magnetothermally induced linear actuation comparable to their virgin counterparts. The actuators are fabricated in different structures, including braided-straight, braided-twisted and braided-coiled, with the coiled configuration showing the highest actuation strain and straight yarn generating maximum stress. The technology also proves to be energy-efficient compared to the prior art, making it suitable for various applications including soft robotics, compliant exoskeletons, smart prostheses and e-textiles. Repurposing abundant waste materials into soft actuators offers a promising solution for managing waste generated from end-of-service soft devices.

The Delta-Motor: A multi-modal, high-speed, flexure-based piezoelectric motor

Here we present a new type of piezoelectric motor that uses flexures and a variable-transmission crank-shaft to produce both full rotary and linear actuation in the same device, at the same frequency as the input (piezoelectric drive) frequency. This multi-modal design weighs only 130 mg and has achieved rotational rates up to 30,000 RPM (orders of magnitude higher than typical piezoelectric motors) and a peak torque of 2.5 μNm. In the linear mode, it has demonstrated a blocked force of ±100 mN and a free displacement of ±0.6 mm up to at least 500 Hz in output frequency. The rotary and linear modes of operation can be activated independently (e.g., to switch gears) or simultaneously (to produce complex output motions).