A survey on the mechanical design for piezo-actuated compliant micro-positioning stages.

This paper presents a comprehensive review of mechanical design and synthesis methods for piezo-actuated compliant micro-positioning stages, which play an important role in areas where high precision motion is required, including bio-robotics, precision manufacturing, automation, and aerospace. Unlike conventional rigid-link mechanisms, the motion of compliant mechanisms is realized by using flexible elements, whereby deformation requires no lubrication while achieving high movement accuracy without friction. As compliant mechanisms differ significantly from traditional rigid mechanisms, recent research has focused on investigating various technologies and approaches to address challenges in the flexure-based micro-positioning stage in the aspects of synthesis, analysis, material, fabrication, and actuation.

The Navigation of Mobile Robot in the Indoor Dynamic Unknown Environment Based on Decision Tree Algorithm.

This study proposes an optimized algorithm for the navigation of the mobile robot in the indoor and dynamic unknown environment based on the decision tree algorithm. Firstly, the error of the yaw value outputted from IMU sensor fusion module is analyzed in the indoor environment; then, the adaptive FAST SLAM is proposed to optimize the yaw value from the odometer; in the next, a decision tree algorithm is applied which predicts the correct moving direction of the mobile robot through the outputted yaw value from the IMU sensor fusion module and adaptive FAST SLAM of the odometer data in the indoor and dynamic environment; the following is the navigation algorithm proposed for the mobile robot in the dynamic and unknown environment; finally, a real mobile robot is designed to verify the proposed algorithm.The final result shows the proposed algorithms are valid and effective.

Identification of Preisach Model Parameters Based on an Improved Particle Swarm Optimization Method for Piezoelectric Actuators in Micro-Manufacturing Stages.

The Preisach model is a typical scalar mathematical model used to describe the hysteresis phenomena, and it attracts considerable attention. However, parameter identification for the Preisach model remains a challenging issue. In this paper, an improved particle swarm optimization (IPSO) method is proposed to identify Preisach model parameters.

Design and Modeling of a Novel Tripteron-Inspired Triaxial Parallel Compliant Manipulator with Compact Structure.

Compliant mechanisms are popular to the applications of micro/nanoscale manipulations. This paper proposes a novel triaxial parallel-kinematic compliant manipulator inspired by the Tripteron mechanism. Compared to most conventional triaxial compliant mechanisms, the proposed manipulator has the merits of structure compactness and being free of assembly error due to its unique configuration and the utilize of 3D printing technology.

DCPR-GAN: Dental Crown Prosthesis Restoration Using Two-Stage Generative Adversarial Networks.

Restoring the correct masticatory function of broken teeth is the basis of dental crown prosthesis rehabilitation. However, it is a challenging task primarily due to the complex and personalized morphology of the occlusal surface. In this article, we address this problem by designing a new two-stage generative adversarial network (GAN) to reconstruct a dental crown surface in the data-driven perspective.

Development of a 3-DOF Flexible Micro-Motion Platform Based on a New Compound Lever Amplification Mechanism.

In this paper, a flexible micro-operation platform with three degrees of freedom, large stroke, and high precision is designed to meet the higher demands in the fields of biological engineering and medicine. The platform adopts a compound lever mechanism. The theoretical magnification of the mechanism is 9.

miR-140-5p regulates vascular smooth muscle cell viability, migration and apoptosis by targeting ROBO4 gene expression in atherosclerosis.

MicroRNAs (miRs) are essential regulators of atherosclerosis (AS) development; however, the pathogenic roles of miR-140-5p during AS development are not completely understood. The present study investigated the effects of miR‑140-5p on human vascular smooth muscle cells (VSMCs) and its target gene. miR-140-5p and roundabout guidance receptor 4 (ROBO4) mRNA expression levels were determined by performing reverse transcription-quantitative PCR.

An Investigation on a Novel 3-RCU Flexible Micromanipulator.

A novel type of spatial three revolute-cylindrical-universal (3-RCU) flexible micro manipulator is designed based on flexible hinges, and analyzed by finite element analysis (FEA). The piezoelectric actuators are adopted as driving devices in this platform, a new lever amplification mechanism is designed as its micro-displacement amplification mechanism, the workspace of the platform is enlarged, and the theoretical and simulation amplification ratios of the amplification mechanism are 3.056 and 2.

Electromechanical Dynamics Model of Ultrasonic Transducer in Ultrasonic Machining Based on Equivalent Circuit Approach.

Ultrasonic transducer is a piezoelectric actuator that converts AC electrical energy into ultrasonic mechanical vibration to accelerate the material removal rate of workpiece in rotary ultrasonic machining (RUM). In this study, an impedance model of the ultrasonic transducer is established by the electromechanical equivalent approach. The impedance model not only facilitates the structure design of the ultrasonic transducer, but also predicts the effects of different mechanical structural dimensions on the impedance characteristics of the ultrasonic transducer.

Hysteresis Compensation and Sliding Mode Control with Perturbation Estimation for Piezoelectric Actuators.

Based on the background of atomic force microscope (AFM) driven by piezoelectric actuators (PEAs), this paper proposes a sliding mode control coupled with an inverse Bouc⁻Wen (BW) hysteresis compensator to improve the positioning performance of PEAs. The intrinsic hysteresis and creep characteristics degrade the performance of the PEA and cause accuracy loss. Although creep effect can be eliminated by the closed-loop control approach, hysteresis effects need to be compensated and alleviated by hysteresis compensators.

A Memetic Algorithm for Global Optimization of Multimodal Nonseparable Problems.

It is a big challenging issue of avoiding falling into local optimum especially when facing high-dimensional nonseparable problems where the interdependencies among vector elements are unknown. In order to improve the performance of optimization algorithm, a novel memetic algorithm (MA) called cooperative particle swarm optimizer-modified harmony search (CPSO-MHS) is proposed in this paper, where the CPSO is used for local search and the MHS for global search. The CPSO, as a local search method, uses 1-D swarm to search each dimension separately and thus converges fast.

A modified PSO structure resulting in high exploration ability with convergence guaranteed.

Particle swarm optimization (PSO) is a population-based stochastic recursion procedure, which simulates the social behavior of a swarm of ants or a school of fish. Based upon the general representation of individual particles, this paper introduces a decreasing coefficient to the updating principle, so that PSO can be viewed as a regular stochastic approximation algorithm. To improve exploration ability, a random velocity is added to the velocity updating in order to balance exploration behavior and convergence rate with respect to different optimization problems.