Development of a Spherical Linkage Mechanism with the Aid of the Dynamic Spatial Geometry Program “GECKO”

2008 ◽  
pp. 125-132
Author(s):  
G. Lonij ◽  
Mathias Husing ◽  
S.W. Choi ◽  
Burkhard Corves
Keyword(s):  
Linkage Mechanism ◽  
Spatial Geometry

scholarly journals A Piezoelectric Wave-Energy Converter Equipped with a Geared-Linkage-Based Frequency Up-Conversion Mechanism

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 204
Author(s):  
Shao-En Chen ◽  
Ray-Yeng Yang ◽  
Guang-Kai Wu ◽  
Chia-Che Wu
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Wave Motion ◽  
Wave Energy Converter ◽  
Gear Train ◽  
Piezoelectric Composite ◽  
Maximum Height ◽  
Resistive Load ◽  
Linkage Mechanism ◽  
Energy Converter

In this paper, a piezoelectric wave-energy converter (PWEC), consisting of a buoy, a frequency up-conversion mechanism, and a piezoelectric power-generator component, is developed. The frequency up-conversion mechanism consists of a gear train and geared-linkage mechanism, which converted lower frequencies of wave motion into higher frequencies of mechanical motion. The slider had a six-period displacement compared to the wave motion and was used to excite the piezoelectric power-generation component. Therefore, the operating frequency of the piezoelectric power-generation component was six times the frequency of the wave motion. The developed, flexible piezoelectric composite films of the generator component were used to generate electrical voltage. The piezoelectric film was composed of a copper/nickel foil as the substrate, lead–zirconium–titanium (PZT) material as the piezoelectric layer, and silver material as an upper-electrode layer. The sol-gel process was used to fabricate the PZT layer. The developed PWEC was tested in the wave flume at the Tainan Hydraulics Laboratory, Taiwan (THL). The maximum height and the minimum period were set to 100 mm and 1 s, respectively. The maximum voltage of the measured value was 2.8 V. The root-mean-square (RMS) voltage was 824 mV, which was measured through connection to an external 495 kΩ resistive load. The average electric power was 1.37 μW.

scholarly journals Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

2021 ◽  
Vol 9 (3) ◽  
pp. 256
Author(s):  
Wei Liu ◽  
Hao Tang ◽  
Xinxing You ◽  
Shuchuang Dong ◽  
Liuxiong Xu ◽  
...  
Keyword(s):  
Drag Force ◽  
Mesh Size ◽  
Current Speed ◽  
Midwater Trawl ◽  
Minimum Drag ◽  
Fish Catch ◽  
Spatial Geometry ◽  
By Catch ◽  
Trawl Fisheries ◽  
Crucial Part

The codend of a trawl net is the rearmost and crucial part of the net for selective fish catch and juvenile escape. To ensure efficient and sustainable midwater trawl fisheries, it is essential to better understand the drag characteristics and fluttering motions of a midwater trawl codend. These are generally affected by catch, cutting ratio, mesh size, and twine diameter. In this study, six nylon codend models with different cutting ratios (no cutting, 6:1, 5:1, 4:1, 7:2, and 3:1) were designed and tested in a professional flume tank under two conditions (empty codends and codends with catch) and five current speeds to obtain the drag force, spatial geometry, and movement trend. As the cutting ratio of empty codends decreased, the drag force decreased, and the drag coefficient increased. The unfolding degree of codend netting and the height of empty codends were found to be directly proportional to the current speed and inversely proportional to the cutting ratio. The positional amplitude of codend with cutting ratio 4:1 was the smallest for catch. The drag force of codends with catch increased as the current speed increased, and first decreased and then increased as the cutting ratio decreased. To ensure the best stability and minimum drag force of the codend, it is recommended to use the 4:1 cutting ratio codend.

scholarly journals Scalable six bar linkage mechanism for re-orienting and aligning objects: Design methodology

Procedia CIRP ◽  
2021 ◽  
Vol 97 ◽  
pp. 66-70
Author(s):  
Emanuela Elisa Cepolina ◽  
Isiah Zaplana ◽  
MariaPaola D’Imperio ◽  
Roberto Gagliardi ◽  
Khelifa Baizid ◽  
...  
Keyword(s):  
Design Methodology ◽  
Linkage Mechanism

scholarly journals The Effectiveness of the Ecological Forest Rangers Policy in Southwest China

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 746
Author(s):  
Yifan Wang ◽  
Dengju Wang ◽  
Rong Zhao
Keyword(s):  
Poverty Alleviation ◽  
Southwest China ◽  
Rural Poverty ◽  
Ecological Effect ◽  
Income Growth ◽  
Future Research ◽  
Linkage Mechanism ◽  
Short Term ◽  
Forest Protection

To achieve the dual goal of poverty alleviation and ecological restoration, the policy of ecological forest rangers (EFRs) was implemented in rural poverty-stricken areas in China, where local residents commonly depend on nearby forest resources for livelihoods. This study aimed to analyze the short-term and long-term effectiveness of the EFRs policy in China mainly in poverty alleviation and income growth, with a brief discussion on the ecological effect of the policy. A questionnaire survey was conducted in four counties in the Karst rocky desertification region in southwest China. By combing through the early literature on REDD+, community forestry, leasehold forestry, etc., this paper summarizes the experience and lessons of similar community forest management models, aiming to explain the unsustainability of EFRs policy from the perspective of forest tenure and governance. The findings of the effectiveness analysis of EFRs policy in the four poverty-stricken counties reflect different degrees of effect in rural households with different income levels. We believe that the EFRs policy has played important roles in short-term regional poverty alleviation while its potential for long-term income growth has not been stimulated. For the amendment of EFRs policy, we put forward the following points: (1) It is necessary to redesign the selection and recruitment mechanism, as well as the exit mechanism of EFRs adapting to the local conditions. (2) It is advisable to further improve the local assessment and monitoring system of forest protection quality of EFRs and optimize the establishment of benefit linkage mechanism between protection effectiveness and EFRs remuneration. (3) The EFRs remuneration standards should be dynamically raised to assure the active participation of EFRs in forest protection. Furthermore, there is a need for one more effective integration model of forest protection and rural livelihoods improvement, which is considered as a potential future research direction.

scholarly journals Dynamic multistep uncertainty prediction in spatial geometry

Procedia CIRP ◽  
2021 ◽  
Vol 96 ◽  
pp. 74-79
Author(s):  
Alex Grenyer ◽  
Oliver Schwabe ◽  
John A. Erkoyuncu ◽  
Yifan Zhao
Keyword(s):  
Uncertainty Prediction ◽  
Spatial Geometry

Structural design and gait research of a new bionic quadruped robot

2021 ◽  
pp. 095440542199566
Author(s):  
Jiu-Peng Chen ◽  
Hong-Jun San ◽  
Xing Wu ◽  
Bin-Zhou Xiong
Keyword(s):  
Stability Margin ◽  
Static Stability ◽  
Quadruped Robot ◽  
Superior Performance ◽  
Linkage Mechanism ◽  
Wide Range ◽  
Planning Algorithm ◽  
Planning Experiment ◽  
Strength And Stiffness ◽  
Foot Trajectory

Quadruped bionic robot has a strong adaptability to the environment, compared with wheeled and tracked robots, it has superior motion performance, and has a wide range of application prospects in rescue and disaster relief, ground mine clearance, mountain transportation, so it has become a research hotspot all over the world. Leg structure is an important embodiment of the superior performance of quadruped robot, and it is also the key and difficult point of design. This article proposes a novel quadruped robot with waist structure, which can complete a variety of gait forms. Based on the theory of linkage mechanism, a novel leg structure is designed with anti-parallelogram mechanism, which improves the strength and stiffness of the robot. Using D-H description method, the kinematics analysis of this quadruped robot single leg is carried out. On this basis, in order to ensure the foot contact with the ground and achieve zero impact, polynomial programming is used to plan the foot trajectory of swing phase and support phase. Based on the static stability margin, the optimal static gait of the quadruped robot is planned. A co-simulation study has been carried out to investigate further the validity and effectiveness of the quadruped robot on gait. The simulation results clearly show the robot can walk steadily and its input and output meet the expected requirements. The solid prototype platform is built, and the trajectory planning experiment of single leg is carried out, and the foot trajectory of single leg is obtained by using laser tracker. The gait planning algorithm is applied to the whole robot, and the results show that the robot can walk according to the scheduled gait, which proves the effectiveness of the proposed algorithm.

ON THE HYBRID-DRIVEN LINKAGE MECHANISM WITH ONE INPUT CYCLE CORRESPONDING TO TWO OUTPUT CYCLES

2015 ◽  
Vol 39 (3) ◽  
pp. 637-646
Author(s):  
Ren-Chung Soong
Keyword(s):  
Kinematic Analysis ◽  
Angular Speed ◽  
Motion Trajectory ◽  
Dimensional Synthesis ◽  
Reciprocating Motion ◽  
Linkage Mechanism ◽  
Output Link ◽  
Input And Output ◽  
Single Input ◽  
Selection Of

A hybrid-driven five-bar linkage mechanism with one input cycle corresponding to two output cycles is presented. The proposed linkage mechanism is driven by a constant-speed motor and a linear motor, respectively. The output link can generate two same required output cycles during a single input cycle, while the rotational input link rotates with a constant angular speed, and the linear input link follows a reciprocating motion along a specified linear guide fixed on the rotational input link. The configuration, displacement relationship between the input and output links, and conditions of mobility of this proposed mechanism were studied, and a kinematic analysis was performed. The selection of the instantaneous motion trajectory of the linear input link and an optimal dimensional synthesis are also described. An example is provided to verify the feasibility and effectiveness of this methodology.

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