Fabrication of a piezoelectrically driven micropositioning 3-DOF stage with elastic body using a multi-material 3D printer

2020 ◽  
Vol 26 (9) ◽  
pp. 1579-1591
Author(s):  
Sang-Woo Baek ◽  
Nahm-Gyoo Cho ◽  
Dong-Hyeok Lee
Keyword(s):  
Elastic Body ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Experimental Results ◽  
Analysis Model ◽  
Content Type ◽  
Vision Measurement ◽  
Conventional Material ◽  
Single Material

Purpose This paper aims to propose a method for manufacturing multi-material monolithic structures with flexible materials to construct the elastic body by using a dual-nozzle three-dimensional printer to develop a piezoelectric (PZT)-driven micropositioning stage with three degrees of freedom (3-DOF) and flexure hinges. Design/methodology/approach Polylactic acid (PLA) and nylon were used for the lever structure’s frame and flexure hinge, respectively. Additionally, the stage consisted of three PZT actuators for fine movement in the nanometer scale in 3-DOF (x, y and θ-directions). For the design of the stage, the kinematic analysis model and the finite element method (FEM) analysis was undertaken for comparing between PLA with nylon (multi-material), PLA (single material) and aluminum (conventional-material). In addition, two verification experiments were implemented for the fabricated prototype stage. First, to evaluate various assessments (lever ratio, hysteresis, coupling error and resolution), a measurement is carried out using the three capacitive sensors. Then, a two-camera-vision measurement experiment was performed to verify the displacement and lever ratio over the full-scale working range of the fabricated positioning stage, and the results from the experimentation and the FEM analysis were compared. Findings The authors confirmed enhancements in the properties of the lever structure frame, which requires stiffness and of the hinge, which requires flexibility for elastic deformation. Comparing FEM analysis and experimental results, although the performance as shown by experimental results was lower: the maximum difference being 3.4% within the end-point working range; this difference was sufficient to be a plausible alternative for the aluminum-based stage. Originality/value Multi-material monolithic-structure fabrication has an effective advantage in improving the performance of the stage, by using a combination of materials capable of reinforcing the desired characteristics in the necessary parts. It was verified that the fabricated stage can substitute the aluminum-based stage and can achieve a higher performance than single-material stages. Thus, precise-positioning stages can be manufactured in many kinds of structures with various properties and contribute to weight reduction and low costs for application equipment.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Experimental System and Creation of Virtual Guiding Surfaces)

2013 ◽  
Vol 25 (2) ◽  
pp. 285-293 ◽  
Author(s):  
Mineo Higuchi ◽  
◽  
Tsukasa Ogasawara ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Experimental System ◽  
Major Axis ◽  
Experimental Results ◽  
Physical Interaction ◽  
Assist Device ◽  
Two Degrees Of Freedom ◽  
Direct Physical Interaction ◽  
Continuously Variable Transmissions

We describe a new robotic assist device: the passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator. PASArms are physically passive. The force to manipulate the arm end must be provided by the operator. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces that constrain and guide the motion of the operator. PAS-Arms have three joints and a three dimensional workspace, but possess only two degrees of freedom due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. In this paper, we first discuss the manipulability ellipsoid for the PAS-Arm. The major axis of the ellipsoid is the direction in which the arm end may be easily manipulated, and vice versa. We have developed an experimental system for the PAS-Arm. The CVTs of the experimental system may not adjust the transmission ratio to zero. Second, we describe an algorithm to address that problem. Finally, we present initial experiments that verify the PAS-Arm mechanism. The experimental results successfully produced virtual guiding surfaces.1 1. This paper is the full translation from the transactions of JSME, Series C, Vol.76, No.763, pp. 611-618, 2010.

A personalized mandibular implant with supporting and porous structures designed with topology optimization – a case study of canine

2019 ◽  
Vol 25 (2) ◽  
pp. 417-426 ◽  
Author(s):  
Kangjie Cheng ◽  
Yunfeng Liu ◽  
Chunyan Yao ◽  
Wenquan Zhao ◽  
Xu Xu
Keyword(s):  
Topology Optimization ◽  
Optimal Design ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Von Mises Stress ◽  
Content Type ◽  
Optimized Model ◽  
Supporting Structures ◽  
External Shape

Purpose The purpose of this study is to obtain a titanium mandibular implant that possesses a personalized external shape for appearance recovery, a supporting structure for physiological loading and numerous micro-pores for accelerating osseointegration. Design/methodology/approach A three-dimensional intact mandibular model of a beagle dog was created from cone-beam computerized tomography scans. A segment of the lower jaw bone was resected and replaced by a personalized implant with comprehensive structures including a customized external shape, supporting structures and micro-pores, which were designed by topology optimization. Then with FEM analysis, the stress, displacement distribution and compliance of the designed implant were compared with the non-optimized model. The weight of the optimized implant that was fabricated by SLM with titanium alloy powder was measured and contrasted with the predicted non-optimized model for evaluating the viability of the design. Findings The FEM results showed the peaks of von Mises stress and displacement on the optimized implant were much lower than those of the implant without optimization. With topology optimization, the compliance of the implant decreased significantly by 53.3 per cent, and a weight reduction of 37.2 per cent could be noticed. Originality/value A design strategy for personalized implant, with comprehensive structures and SLM as the fabrication method, has been developed and validated by taking a canine mandible as the case study. With comprehensive structures, the implant presented good biomechanical behaviors thanks to the most appropriate supporting structures obtained by optimal design. The topological optimal design combined with SLM printing proved to be an effective method for the design and fabrication of personalized implant with complex structures.

Equivalence relationship between a three-axis centrifugal test load and flight load

2018 ◽  
Vol 07 (01n02) ◽  
pp. 1850011
Author(s):  
Gege Liu ◽  
Yahong Zhang ◽  
Xinong Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Equivalence Relations ◽  
Analysis Model ◽  
High Acceleration ◽  
Energy Equivalence ◽  
Acceleration Analysis ◽  
Equivalence Relationship ◽  
Centrifugal Test

For aircraft flying with high accelerations and high acceleration change rates in three-dimensional space, load simulation tests are usually carried out in a three-axis centrifuge with three degrees of freedom. A triaxial centrifugal test that simulates the actual flight environment must reflect the real effect of the flight load on the structure. An acceleration analysis model of a three-axis centrifuge in body coordinates is established to meet this requirement. The spatial distribution of the acceleration and the effects of kinematic parameters on acceleration are analyzed. Using the acceleration analysis model, the displacement equivalence and strain energy equivalence relations of a beam in a centrifugal environment and actual flight environment are studied. Moreover, equivalence relationships meeting requirements are proposed and validated for a specific example. The distribution of the acceleration and the equivalence relations of the two environments are the basis for the ground simulation of flight loads.

scholarly journals 3D textile reconstruction based on KinectFusion and synthesized texture

2017 ◽  
Vol 29 (6) ◽  
pp. 793-806 ◽  
Author(s):  
PengPeng Hu ◽  
Taku Komura ◽  
Duan Li ◽  
Ge Wu ◽  
Yueqi Zhong
Keyword(s):  
Artificial Intelligence ◽  
Design Methodology ◽  
3D Model ◽  
Three Dimensional ◽  
Experimental Results ◽  
High Quality ◽  
Content Type

Purpose The purpose of this paper is to present a novel framework of reconstructing the 3D textile model with synthesized texture. Design/methodology/approach First, a pipeline of 3D textile reconstruction based on KinectFusion is proposed to obtain a better 3D model. Second, “DeepTextures” method is applied to generate new textures for various three-dimensional textile models. Findings Experimental results show that the proposed method can conveniently reconstruct a three-dimensional textile model with synthesized texture. Originality/value A novel pipeline is designed to obtain 3D high-quality textile models based on KinectFusion. The accuracy and robustness of KinectFusion are improved via a turntable. To the best of the authors’ knowledge, this is the first paper to explore the synthesized textile texture for the 3D textile model. This is not only simply mapping the texture onto the 3D model, but also exploring the application of artificial intelligence in the field of textile.

Kinematics-searched framework for quadruped traversal in a parallel robot

2019 ◽  
Vol 47 (2) ◽  
pp. 267-279 ◽  
Author(s):  
Fei Guo ◽  
Shoukun Wang ◽  
Junzheng Wang ◽  
Huan Yu
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Parallel Robot ◽  
Whole Body ◽  
Search Region ◽  
Receding Horizon ◽  
Content Type ◽  
Foot Placement ◽  
Quadruped Locomotion ◽  
Computation Efficiency

Purpose In this research, the authors established a hierarchical motion planner for quadruped locomotion, which enables a parallel wheel-quadruped robot, the “BIT-NAZA” robot, to traverse rough three-dimensional (3-D) terrain. Design/methodology/approach Presented is a novel wheel-quadruped mobile robot with parallel driving mechanisms and based on the Stewart six degrees of freedom (6-DOF) platform. The task for traversing rough terrain is decomposed into two prospects: one is the configuration selection in terms of a local foothold cost map, in which the kinematic feasibility of parallel mechanism and terrain features are satisfied in heuristic search planning, and the other one is a whole-body controller to complete smooth and continuous motion transitions. Findings A fan-shaped foot search region focuses on footholds with a strong possibility of becoming foot placement, simplifying computation complexity. A receding horizon avoids kinematic deadlock during the search process and improves robot adaptation. Research limitations/implications Both simulation and experimental results validated the proposed scenario available and appropriate for quadruped locomotion to traverse challenging 3-D terrains. Originality/value This paper analyzes kinematic workspace for a parallel robot with 6-DOF Stewart mechanism on both body and foot. A fan-shaped foot search region enhances computation efficiency. Receding horizon broadens the preview search to decrease the possibility of deadlock minima resulting from terrain variation.

Numerical simulation of keyhole behaviors and droplet transfer in laser-MIG hybrid welding of Invar alloy

2018 ◽  
Vol 28 (9) ◽  
pp. 1974-1993 ◽  
Author(s):  
Dan Zhang ◽  
Yanhong Wei ◽  
Xiaohong Zhan ◽  
Jie Chen ◽  
Hao Li ◽  
...  
Keyword(s):  
Heat Source ◽  
Three Dimensional ◽  
Welding Process ◽  
Source Model ◽  
Experimental Results ◽  
Invar Alloy ◽  
Hybrid Welding ◽  
Droplet Transfer ◽  
Heat Source Model ◽  
Content Type

Purpose This paper aims to describe a three-dimensional mathematical and numerical model based on finite volume method to simulate the fluid dynamics in weld pool, droplet transfer and keyhole behaviors in the laser-MIG hybrid welding process of Fe36Ni Invar alloy. Design/methodology/approach Double-ellipsoidal heat source model and adaptive Gauss rotary body heat source model were used to describe electric arc and laser beam heat source, respectively. Besides, recoil pressure, electromagnetic force, Marangoni force, buoyancy as well as liquid material flow through a porous medium and the heat, mass, momentum transfer because of droplets were taken into consideration in the computational model. Findings The results of computer simulation, including temperature field in welded plate and velocity field in the fusion zone were presented in this article on the basis of the solution of mass, momentum and energy conservation equations. The correctness of elaborated models was validated by experimental results and this proposed model exhibited close correspondence with the experimental results with respect to weld geometry. Originality/value It lays foundation for understanding the physical phenomena accompanying hybrid welding and optimizing the process parameters for laser-MIG hybrid welding of Invar alloy.

Resiliency cube

2018 ◽  
Vol 9 (4/5) ◽  
pp. 317-332 ◽  
Author(s):  
Amirpurya Chavoshy ◽  
Kambod Amini Hosseini ◽  
Mahmood Hosseini
Keyword(s):  
Three Dimensional ◽  
Road Networks ◽  
Decision Support Tool ◽  
Analysis Model ◽  
Content Type ◽  
Support Tool ◽  
Earthquake Scenarios ◽  
Urban Road ◽  
Emergency Situations ◽  
Graphical Modelling

Purpose This study aims to provide resiliency against earthquakes to the framework of an urban road network and to construct a comprehensive model with sufficient computational detail to assist metropolitan managers as a decision support tool in emergency situations via parametric analysis (model behaviour analysis with parameter changes) to quantify the consequences of decisions. Design/methodology/approach Performed stages are: developing existing resilience assessment frameworks for use against earthquakes in urban road networks, identifying earthquake scenarios and estimating the weight of components using AHP, including an example modelling of Tehran; and developing modelling software (using Matlab®). Findings This study produced a software that performs three-dimensional (3D) graphical modelling, resiliency index measurements and its parametric analyses for the road networks against earthquakes. Based on this model, a prioritized list of upgrades is also introduced. The developed tool also addresses issues regarding the allocation of limited resources between the network components. Research limitations/implications Because of the novelty of the study, there is limited literature on this topic. Practical implications The developed model provides urban managers with a comprehensive list of upgrades and empowering them to graphically and numerically evaluate the resiliency changes as they alter the parameters of these measures and balance their decisions based on available funding. Originality/value In contrast to previous studies, this study has focused on all of these three keywords: resiliency, earthquake and road networks, and not only two of them.

Evaluation of influence of target location on robot repeatability

Robotica ◽  
2000 ◽  
Vol 18 (4) ◽  
pp. 443-449 ◽  
Author(s):  
Raziel Riemer ◽  
Yael Edan
Keyword(s):  
Error Analysis ◽  
Target Location ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Experimental Results ◽  
Target Point ◽  
Analysis Model ◽  
Significant Statistical Difference ◽  
Optimal Target ◽  
Set Up

This paper evaluates the influence of target location on robot repeatability. An experiment was set up to analyze the effect of the three-dimensional target location on robot repeatability. An error-analysis model to determine repeatability based on the robot's kinematic model and known robot parameters was developed. Experimental results indicated that there was a significant statistical difference between repeatability at different locations in the workspace and that the height of the target point influenced repeatability. Experimental results tended to those derived from the error-analysis kinematic model. Hence, to determine the optimal target location, there is no need for extensive experimentation; instead, only a few target points can be sampled and compared to an error-analysis model.

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