HIGH-PERFORMANCE MULTI-BODY COLLISION DETECTION FOR THE REAL-TIME CONTROL OF A CTS SYSTEM

2005 ◽  
Vol 29 (2) ◽  
pp. 163-177
Author(s):  
M. Ahmadi ◽  
M. Jaber ◽  
F.C. Tang

This paper presents a high performance methodology for the real-time implementation of collision detection on a Captive Trajectory Simulation (CTS) system. The CTS system includes a slow-moving redundant robot manipulator operating inside a wind tunnel environment with transonic conditions. Collisions can occur between robot links or the links and other objects present in the environment. A multi-body dynamic pruning method is proposed based on joint velocity bounds, which can significantly reduce the number of required collision checks without compromising the system’s safety due to its conservative assumptions. A balance is achieved between the accuracy and the speed of computations via the convex subhull subdivision of the objects, which reduces the geometrical details to further decrease the load of computations. Combining the above two strategies results in smaller and more consistent sample times allowing the collision detection to run in real-time as an integral part of a robot with a high speed control loop.

Author(s):  
Vladimir V. NEKRASOV

Developing a microcontroller-based system for controlling the flywheel motor of high-dynamics spacecraft using Russian-made parts and components made it possible to make statement of the problem of searching control function for a preset rotation rate of the flywheel rotor. This paper discusses one of the possible options for mathematical study of the stated problem, namely, application of structural analysis based on graph theory. Within the framework of the stated problem a graph was constructed for generating the new required rate, while in order to consider the stochastic case option the incidence and adjacency matrices were constructed. The stated problem was solved using a power matrix which transforms a set of contiguous matrices of the graph of admissible solution edge sequences, the real-time control function was found. Based on the results of this work, operational trials were run for the developed control function of the flywheel motor rotor rotation rate, a math model was constructed for the real-time control function, and conclusions were drawn about the feasibility of implementing the results of this study. Key words: Control function, graph, incidence matrix, adjacency matrix, power matrix, microcontroller control of the flywheel motor, highly dynamic spacecraft.


2017 ◽  
Vol 28 (10) ◽  
pp. 1750126 ◽  
Author(s):  
Yutong Liu ◽  
Chengxuan Cao ◽  
Yaling Zhou ◽  
Ziyan Feng

In this paper, an improved real-time control model based on the discrete-time method is constructed to control and simulate the movement of high-speed trains on large-scale rail network. The constraints of acceleration and deceleration are introduced in this model, and a more reasonable definition of the minimal headway is also presented. Considering the complicated rail traffic environment in practice, we propose a set of sound operational strategies to excellently control traffic flow on rail network under various conditions. Several simulation experiments with different parameter combinations are conducted to verify the effectiveness of the control simulation method. The experimental results are similar to realistic environment and some characteristics of rail traffic flow are also investigated, especially the impact of stochastic disturbances and the minimal headway on the rail traffic flow on large-scale rail network, which can better assist dispatchers in analysis and decision-making. Meanwhile, experimental results also demonstrate that the proposed control simulation method can be in real-time control of traffic flow for high-speed trains not only on the simple rail line, but also on the complicated large-scale network such as China’s high-speed rail network and serve as a tool of simulating the traffic flow on large-scale rail network to study the characteristics of rail traffic flow.


RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86490-86496 ◽  
Author(s):  
Tianqi Ma ◽  
Shaohui Guo ◽  
Zhihui Guo ◽  
Qiushi Zhu ◽  
Jinfu Chen

Indicated high pH benefits the accuracy of real-time control strategy, explained why DO as a control parameter is unreliable.


2000 ◽  
Vol 618 ◽  
Author(s):  
D.A. Gajewski ◽  
J.E. Guyer ◽  
J.J. Kopanski ◽  
J.G. Pellegrino

ABSTRACTWe present the real-time pseudodielectric function <ε(E)> of low-temperature-grown GaAs (LT-GaAs) thin films during the growth as a function of growth temperature Tg and thickness. We obtained accurate measurements of the real-time <εc(E)> by using in situspectroscopic ellipsometry (SE) in conjunction with active feedback control of the substrate temperature using diffuse reflectance spectroscopy. We show that for epitaxial LT-GaAs layers, the peak in the imaginary pseudodielectric function <ε2(E)> decreases in amplitude and sharpness systematically with decreasing Tg. We also revealed an abrupt change in <εc(E)> near the critical epitaxial thickness hepi, the value of which decreases with decreasing Tg. Above hepi, the LT-GaAs grows polycrystalline (amorphous) above (below) Tg ∼ 190°C. We also simultaneously monitored the surface roughness and crystallinity by using real-time reflection high-energy electron diffraction (RHEED). These results represent progress in obtaining real-time control over the composition and morphology of LT-GaAs


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