Motion planning with obstacle avoidance of an UR3 robot using charge system search

Chih-Jer Lin,Ming-Yen Li 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

For a cyber-physical system (CPS) of a future intelligent factory, a robotic manipulator is requested to co-work with human efficiently and safely in an environment with flexible arrangements. Therefore, an autonomous path planning of robotic manipulator is the most necessary issue to be resolved for the factory automation. For the robotic manipulator, optimizations and artificial intelligence (AI) methods are widely used to investigate the autonomous dynamic path-planning tasks with obstacle avoidance. Among these methods, the Rapidly Exploring Random Tree (RRT) algorithm has been widely used in path planning for a complex environment, because the RRT algorithm has the advantages of perfect expansion, probability completeness, and fast exploring speed. However, for some practical cases, the existing RRT algorithm may obtain a discontinuous solution of the angular trajectory. To solve the above problem, we studied a particle swarm optimization with the charge search system (CSS) to find the optimal path planning with obstacle avoidance. The steps of the proposed method are mentioned as follows: (1) establish the configuration space with the obstacle regions, (2) formulate the motion planning with obstacle using the CSS method and (3) use the PSO method to solve the path planning problem. Finally, the simulation of the path-planning task with obstacle avoidance is visually illustrated using the software RoboDK and the proposed method is implemented by the real-time experiments of the UR3 robot.

Vibration control for serviceability enhancement of offshore platforms against environmental loadings

Chih-Shiuan Lin,Feifei Liu,Jigang Zhang,Jer-Fu Wang,Chi-Chang Lin 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.3

Offshore drilling has become a key process for obtaining oil. Offshore platforms have many applications, including oil exploration and production, navigation, ship loading and unloading, and bridge and causeway support. However, vibration problems caused by severe environmental loads, such as ice, wave, wind, and seismic loads, threaten the functionality of platform facilities and the comfort of workers. These concerns may result in piping failures, unsatisfactory equipment reliability, and safety concerns. Therefore, the vibration control of offshore platforms is essential for assuring structural safety, equipment functionality, and human comfort. In this study, an optimal multiple tuned mass damper (MTMD) system was proposed to mitigate the excessive vibration of a three-dimensional offshore platform under ice and earthquake loadings. The MTMD system was designed to control the first few dominant coupled modes. The optimal placement and system parameters of the MTMD are determined based on controlled modal properties. Numerical simulation results show that the proposed MTMD system can effectively reduce the displacement and acceleration responses of the offshore platform, thus improving safety and serviceability. Moreover, this study proposes an optimal design procedure for the MTMD system to determine the optimal location, moving direction, and system parameters of each unit of the tuned mass damper.

Damage identification of isolators in base-isolated torsionally coupled buildings

Jer-Fu Wang,Chi-Chang Lin,Ming-Chih Huang,Tzu-Kang Lin 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.4

This paper deals with the damage assessment for isolators of base-isolated building systems considering the torsion-coupling (TC) effect by establishing damage indices. The damage indices can indicate the reduction in lateral stiffness of the isolator story as explicit formulas in terms of modal parameters. In addition, the damage location, expressed in terms of the estimated damage index and eccentricities before and after damage, is also presented. Numerical analysis shows that the proposed algorithms are applicable for general base-isolated multi-story TC buildings. A procedure from the analysis of seismic response to the implementation of damage indices is demonstrated by using a numerical case. A system identification technique is employed to extract modal parameters from seismic responses of a building. Results show that the proposed indices are capable of detecting the occurrence of damage and preliminarily estimating the location of damaged isolator.

Charge storage characteristics of nonvolatile memories with chemically-synthesized and vacuum-deposited gold nanoparticles

Jer-Chyi Wang,Chin-Hsiang Liao,Chih-Ting Lin,Ruey-Dar Chang,Li-Chun Chang,Chih-I Wu,Jung-Hung Chang 한국물리학회 2015 Current Applied Physics Vol.15 No.4

Carrier injection and charge loss characteristics of nonvolatile memories with chemically-synthesized (CS) and vacuum-deposited (VD) gold nanoparticles (Au-NPs) have been investigated. Compared to CS counterparts, the memories with VD Au-NPs exhibit a higher dot density of 3.77 × 1011 cm-2, leading to a larger memory window. Further, the energy from valence-band edge to vacuum level (EVB_vac) of tunneling oxide for the samples with CS and VD Au-NPs is found to be 9.04 and 9.85 eV respectively. The small EVB_vac value of the memories with CS Au-NPs is resulted from the formation of a thin chemical oxide (SiOx) on thermally-grown SiO2 tunneling layer during the chemically synthesized process, contributing to a slow erasing behavior. Besides, the programming of the memories with VD Au-NPs is saturated at high gate bias, which has been well-explained by the electrons induced potential coupling between Au-NPs. Superior data retention property and high temperature dependence of charge loss are observed for the memories with CS Au-NPs, which can be ascribed to the thick tunneling oxide layer by the additional SiOx film.

Effects of charge storage dielectric thickness on hybrid gadolinium oxide nanocrystal and charge trapping nonvolatile memory

Jer-Chyi Wang,Chih-Ting Lin,Chi-Feng Chang 한국물리학회 2014 Current Applied Physics Vol.14 No.3

The characteristics of hybrid gadolinium oxide nanocrystal (Gd2O3-NC) and gadolinium oxide charge trapping (Gd2O3-CT) memories were investigated with different Gd2O3 film thickness. By performing the rapid thermal annealing on Gd2O3 films with different thickness, the Gd2O3-NCs with the diameter of 6 e9 nm for charge storage, surrounded by the amorphous Gd2O3 (a-Gd2O3) layer, were formed. The a-Gd2O3 layer was considered to be the charge trapping layer, resulting in the large memory window of Gd2O3-NC/CT memories with thick Gd2O3 film. The charge trapping energy level of the Gd2O3-NCs and a-Gd2O3 layer was extracted to be 0.16 and 0.45 eV respectively by using the temperature-dependent retention measurement. Further, after a 106 program/erase cycling operation, the memory with thin Gd2O3 film can be predicted to sustain a 94% memory window of the first cycling one while the memory with thick Gd2O3 film suffered from a 30% charge loss because of the traps within the a-Gd2O3 layer. The Gd2O3 film thickness of 10 nm was optimized to exhibit superior performances of the Gd2O3-NC/CT memory, which can be applied into the nonvolatile memory.

Damage identification of isolators in base-isolated torsionally coupled buildings

Wang, Jer-Fu,Huang, Ming-Chih,Lin, Chi-Chang,Lin, Tzu-Kang Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.11 No.4

This paper deals with the damage assessment for isolators of base-isolated building systems considering the torsion-coupling (TC) effect by establishing damage indices. The damage indices can indicate the reduction in lateral stiffness of the isolator story as explicit formulas in terms of modal parameters. In addition, the damage location, expressed in terms of the estimated damage index and eccentricities before and after damage, is also presented. Numerical analysis shows that the proposed algorithms are applicable for general base-isolated multi-story TC buildings. A procedure from the analysis of seismic response to the implementation of damage indices is demonstrated by using a numerical case. A system identification technique is employed to extract modal parameters from seismic responses of a building. Results show that the proposed indices are capable of detecting the occurrence of damage and preliminarily estimating the location of damaged isolator.

Fuzzy Control with Pole Assignment and Variance Constraints for Continuous-time Perturbed Takagi-Sugeno Fuzzy Models: Application to Ship Steering Systems

Wen-Jer Chang,Yan-Horng Lin,Jialu Du,Chih-Ming Chang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.10

The stability analysis and controller design of stochastic systems have become much more important because the stochastic behaviors usually exist in practical nonlinear systems. In this paper, a robust fuzzy controller design approach is proposed with multiple constraints, including state variance constraints, output variance constraints, and pole placement constraints. At first, nonlinear systems are expressed as the Takagi-Sugeno fuzzy model, and the parallel distributed compensation method is applied to design the robust fuzzy controllers. Next, considering the stability analysis and the performance constraints of perturbed Takagi-Sugeno fuzzy models, Lyapunov conditions are developed based on covariance control theory, pole placement theory and robust control theory. By constructing the stability conditions with multiple constraints, the proposed fuzzy control problem can be effectively transferred into the linear matrix inequality problem. It can be solved by the convex optimal programming algorithm. At last, a nonlinear ship steering system is selected to verify the effectiveness and applicability of the proposed robust fuzzy controller design method.

Optimization of Medium Composition for Improving Biomass Production of Lactobacillus plantarum Pi06 Using the Taguchi Array Design and the Box-Behnken Method

Chin-Fa Hwang,Jen-Han Chang,Jer-Yiing Houng,Cheng-Chih Tsai,Chien-Ku Lin,Hau-Yang Tsen 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

An immune-enhancing strain, Lactobacillus plantarum Pi06, isolated from a healthy infant was used for biomass production following optimization of the medium in shake-flask culture. Preliminary studies showed that commercial MRS medium and cultivation under static conditions generated higher biomass production than four other tested media with or without a shaking condition. The selected medium composition, consisting of glucose,yeast extract, soy peptone, ammonium citrate, and corn steep liquor, was further optimized using a systematic method that integrated the Taguchi array design and the Box–Behnken method. The response effects of these factors were first investigated using Taguchi design under an L16 (45) array. The suggested medium composition,derived from Statistica 7.1 using the Taguchi design, was applied to cultivate cells and a biomass of 7.16 g dry cell weight (DCW)/L was obtained. Response surface methodology based on the Box–Behnken method for the three response variables of glucose, yeast extract, and corn steep liquor was then used to further increase the biomass level to 8.94 g DCW/L. The resulting optimum medium consisted of 35 g/L glucose, 35 g/L yeast extract, and 40 mL/L corn steep liquor. Compared with the initial medium, the biomass yield was improved from 4.31 to 8.94 g DCW/L, an enhancement of approximately 107%.