scholarly journals Steady-state and transient responses of a flexible eccentric spinning shaft

2018 ◽  
Vol 46 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Sovan Dasgupta ◽  
John Rajan
2011 ◽  
Vol 403-408 ◽  
pp. 4880-4887
Author(s):  
Sassan Azadi

This research work was devoted to present a novel adaptive controller which uses two negative stable feedbacks with a positive unstable positive feedback. The positive feedback causes the plant to do the break, therefore reaching the desired trajectory with tiny overshoots. However, the two other negative feedback gains controls the plant in two other sides of positive feedback, making the system to be stable, and controlling the steady-state, and transient responses. This controller was performed for PUMA-560 trajectory planning, and a comparison was made with a fuzzy controller. The fuzzy controller parameters were obtained according to the PSO technique. The simulation results shows that the novel adaptive controller, having just three parameters, can perform well, and can be a good substitute for many other controllers for complex systems such as robotic path planning.


1990 ◽  
Vol 192 ◽  
Author(s):  
David Redfield ◽  
Richard H. Bube

ABSTRACTThe existence of saturation (or steady state) in the density of light-induced defects in amorphous Si:H is shown to have major importance for the interpretation of the nature and origin of these defects. First, a number of characteristics of the steady-state and transient responses to light and temperature are described and contrasted. These lead to the conclusion that the saturation value is the only useful criterion of the number of defects in these materials. We then describe a new atomic model for defects, unifying both dopant-induced and light-induced defects. This model invokes foreign atoms in defects, and saturation reflects the limitation imposed by the numbers of such atoms. Many other observed properties of defects are explained by this model.


Author(s):  
A. K. Samantaray ◽  
S. S. Dasgupta ◽  
R. Bhattacharyya

The rotating internal damping or nonconservative circulatory force in a rotor shaft system causes instability beyond a certain threshold rotor spinning speed. However, if the source loading of the drive is considered, then the rotor spin is entrained at the stability threshold and a stable whirl orbit is observed about the unstable equilibrium. As we move toward the use of more and more lightweight rotor dynamic components such as the shaft and the motor, overlooking this frequency entrainment phenomenon while sizing the actuator in the design stage may lead to undesirable performance. This applies to many emerging areas of strategic importance such as in vivo medical robots where flexible probes are used and space robotics applications involving rotating tools. We analyze this spin entrainment phenomenon in a distributed parameter model of a spinning shaft, which is driven by a nonideal dc motor. A drive whose dynamics is influenced by the dynamics of the driven system is called a nonideal source and the whole system is referred to as a nonideal system. In particular, we show the advantages of representing such nonideal drive-system interactions in a modular manner through bond graph modeling as compared to standard equation models where the energetic couplings between dynamic variables are not explicitly shown. The developed modular bond graph model can be extended to include rotor disks and bearings placed at different locations on the shaft. Moreover, the power conserving property of the junction structure of the bond graph model is exploited to derive the source loading expressions, which are then used to analytically derive the steady-state spinning frequency and whirl orbit amplitude as functions of the drive and the rotor system parameters. We show that the higher transverse modes may become unstable before the lower ones under certain parametric conditions. The shaft spinning speed is entrained at the lowest stability threshold among all transverse modes. The bond graph model is used for numerical simulation of the system to validate the steady-state results obtained from the theoretical study.


1977 ◽  
Vol 99 (4) ◽  
pp. 241-248 ◽  
Author(s):  
R. J. Caudill ◽  
W. L. Garrard

This paper examines the effects of spacing policy and control system nonlinearities on the dynamic response of strings of automated transit vehicles operating under automatic velocity and spacing control. Both steady-state and transient responses are studied. Steady-state response is examined by a modification of the describing function technique and transient response is studied by Liapunov procedures. It is shown that a nonlinearity commonly encountered in automated transit vehicles, a limiter on acceleration and deceleration, can result in string instabilities even though a linearized analysis indicates that the string is stable. Although this paper is specifically focused on automated transit systems, some of the results obtained also appear to be applicable to strings of automobiles on freeways.


2015 ◽  
Vol 781 ◽  
pp. 414-417
Author(s):  
Yutthana Kanthaphayao ◽  
Chalermpol Reaungepattanawiwat

This paper illustrates a fuzzy gain scheduling of PI plus derivative controller. The proposed control technique improves the transient response of a DC/DC converter. The proposed control system is easy to implement based on an STM32F4 microcontroller. The performance evaluation was done by an experiment through a boost DC/DC converter, with a 24W load, a 12V input voltage, and a 24V output voltage, respectively. The system operation achieves tight output voltage regulation, both for the steady-state and transient responses.


1959 ◽  
Vol 37 (12) ◽  
pp. 1384-1396 ◽  
Author(s):  
James R. Wait ◽  
Alyce M. Conda

Starting with the known steady-state solutions for diffraction by a perfectly conducting convex surface, the corresponding transient responses are derived using Fourier–Laplace inversion. Explicit results are given for an incident wave which varies with time as a step function.


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