Computationally Efficient Cable Force Calculation Outside the Wrench-Feasible Workspace

Author(s):  
Roland Boumann ◽  
Tobias Bruckmann
2014 ◽  
Vol 587-589 ◽  
pp. 1364-1369
Author(s):  
Cheng Wu ◽  
Jin Yu Liu ◽  
Shui Xing Zhou

Taking the bare arch deformation under gravity as target alignment, the influence matrix that associates the cable forces with segment deformation is obtained via ANSYS program, and the cable force is quickly calculated by MATLAB quadratic programming toolbox. It is illustrated with an example of Guizhou Zong-xi River Bridge, which is a 360-meter concrete filled steel tube bridge in construction, and the calculation process is given. The results show that, this new method has the advantages of high precision and less number of iterations.


2013 ◽  
Vol 859 ◽  
pp. 131-134
Author(s):  
Fu Li Zhao ◽  
Yi Qiang Xiang ◽  
Qiang Qiang Wu

The measurement accuracy of the cable tensions in the hanger rods of concrete filled steel tube arch bridges is important for the correct evaluation of bridges condition. Based on Jinpan Bridge-a half through concrete filled steel tube arch bridge with 80 m span in Tiantai, it was put forward the vibration frequency method for testing and evaluate suspender tensions with the help of analysis vibration characters of the suspender. The precision of cable force calculation formula was verified after comparing the practical tension with the designed tension obtained from tension jack method. Then, according to the test results and values predicted by the presented cable force calculation formula, the cable tensions were adjusted. Cable tension test results in the finished bridge show that this method is feasible.


Robotics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 41 ◽  
Author(s):  
Roland Boumann ◽  
Tobias Bruckmann

Under special circumstances, a cable-driven parallel robot (CDPR) may leave its wrench-feasible-workspace. Standard approaches for the computation of set-point cable forces are likely to fail in this case. The novel nearest corner method for calculating appropriate cable forces when the CDPR is outside of its wrench-feasible-workspace was introduced in former work of the authors. The obtained cable force distributions aim at continuity and generate wrenches close to the desired values. The method employs geometrical operations in the cable force space and promises real-time usability because of its non-iterative structure. In a simplified simulation, a cable break scenario was used to carry out more detailed testing of the method regarding different parameters, a higher number of cables, and the numerical efficiency. A brief discussion about the continuity of the method when entering the wrench-feasible-workspace is presented.


2020 ◽  
Author(s):  
E Bori ◽  
A Navacchia ◽  
L Wang ◽  
L Duxbury ◽  
S McGuan ◽  
...  

Author(s):  
B. Aparna ◽  
S. Madhavi ◽  
G. Mounika ◽  
P. Avinash ◽  
S. Chakravarthi

We propose a new design for large-scale multimedia content protection systems. Our design leverages cloud infrastructures to provide cost efficiency, rapid deployment, scalability, and elasticity to accommodate varying workloads. The proposed system can be used to protect different multimedia content types, including videos, images, audio clips, songs, and music clips. The system can be deployed on private and/or public clouds. Our system has two novel components: (i) method to create signatures of videos, and (ii) distributed matching engine for multimedia objects. The signature method creates robust and representative signatures of videos that capture the depth signals in these videos and it is computationally efficient to compute and compare as well as it requires small storage. The distributed matching engine achieves high scalability and it is designed to support different multimedia objects. We implemented the proposed system and deployed it on two clouds: Amazon cloud and our private cloud. Our experiments with more than 11,000 videos and 1 million images show the high accuracy and scalability of the proposed system. In addition, we compared our system to the protection system used by YouTube and our results show that the YouTube protection system fails to detect most copies of videos, while our system detects more than 98% of them.


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