scholarly journals Kinematic Design of a Seven-Bar Linkage with Optimized Centrodes for Pure-Rolling Cutting

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Biao Liu ◽  
Yali Ma ◽  
Delun Wang ◽  
Shaoping Bai ◽  
Yangyang Li ◽  
...  

A novel method for designing a seven-bar linkage based on the optimization of centrodes is presented in this paper. The proposed method is applied to the design of a pure-rolling cutting mechanism, wherein close interrelation between the contacting lines and centrodes of two pure-rolling bodies is formulated and the genetic optimization algorithm is adopted for the dimensional synthesis of the mechanism. The optimization is conducted to minimize the error between mechanism centrodes and the expected trajectories, subject to the design requirements of the opening distance, the maximum amount of overlap error, and peak value of shearing force. An optimal solution is obtained and the analysis results show that the horizontal slipping and standard deviation of the lowest moving points of the upper shear blade have been reduced by 78.0% and 80.1% and the peak value of shear stress decreases by 29%, which indicate better cutting performance and long service life.

2013 ◽  
Vol 22 (08) ◽  
pp. 1350067 ◽  
Author(s):  
SEYYED AMIR ASGHARI ◽  
ATENA ABDI ◽  
OKYAY KAYNAK ◽  
HASSAN TAHERI ◽  
HOSSEIN PEDRAM

Electronic equipment used in harsh environments such as space has to cope with many threats. One major threat is the intensive radiation which gives rise to Single Event Upsets (SEU) that lead to control flow errors and data errors. In the design of embedded systems to be used in space, the use of radiation tolerant equipment may therefore be a necessity. However, even if the higher cost of such a choice is not a problem, the efficiency of such equipment is lower than the COTS equipment. Therefore, the use of COTS with appropriate measures to handle the threats may be the optimal solution, in which a simultaneous optimization is carried out for power, performance, reliability and cost. In this paper, a novel method is presented for control flow error detection in multitask environments with less memory and performance overheads as compared to other methods seen in the literature.


Robotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Raffaele Di Gregorio

A dimensional synthesis of parallel manipulators (PMs) consists of determining the values of the geometric parameters that affect the platform motion so that a useful workspace with assigned sizes can be suitably located in a free-from-singularity region of its operational space. The main goal of this preliminary dimensioning is to keep the PM far enough from singularities to avoid high internal loads in the links and guarantee a good positioning precision (i.e., for getting good kinematic performances). This paper presents a novel method for the dimensional synthesis of translational PMs (TPMs) and applies it to a TPM previously proposed by the author. The proposed method, which is based on Jacobians’ properties, exploits the fact that TPM parallel Jacobians are block diagonal matrices to overcome typical drawbacks of indices based on Jacobian properties. The proposed method can be also applied to all the lower-mobility PMs with block diagonal Jacobians that separate platform rotations from platform translations (e.g., parallel wrists).


2020 ◽  
Author(s):  
Chen-Yang Ji ◽  
Jin-Guo Liu ◽  
Chen-Chen Wu ◽  
Peng-Yuan Zhao ◽  
Ke-Li Chen

Abstract The Telescopic Tubular Mast (TTM) has excellent performance and is widely used in aerospace. Reasonable parameter design and optimization can shorten development cycle and improve performance for TTM. This paper designed a TTM driven by the bistable carbon reeled composite boom. The equivalent model of the TTM is established and simulated, which can be used as ex-tending structure for the solar sail. The work flow of the solar sail with the TTM is introduced. The natural frequency of the equivalent model and the segmented model is solved respectively using ABAQUS. The TTM under six different load conditions is analyzed. The influence of different factors on the vibration characteristics of the TTM is analyzed and the sensitivity analysis is carried out. Parameters including stiffness, natural frequency, mass and extension ratio are optimized using the multi-objective genetic optimization algorithm. According to the optimization results, the prototype was processed, and the experiment was completed with the equivalent load of solar sail. It provides a reference for the parametric design of the TTM.


2016 ◽  
Vol 30 (3) ◽  
pp. 1405-1412 ◽  
Author(s):  
Ardeshir Moftakhari ◽  
Cyrus Aghanajafi ◽  
Ardalan Moftakhari Chaei Ghazvin

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