Rotor oscillation and stability in complex motion

1999 ◽  
Vol 35 (7) ◽  
pp. 741-744 ◽  
Author(s):  
P. P. Lizunov ◽  
A. A. Grom ◽  
I. N. Levchenko
Author(s):  
Julie Mapes Lindholm ◽  
Paul A. Wetzel ◽  
Timothy M. Askins

2012 ◽  
Author(s):  
Joshua Haworth ◽  
Nathaniel Hunt ◽  
Yawen Yu ◽  
Nicholas Stergiou

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Liuhao Zhu ◽  
Miaomiao Tang ◽  
Hehe Li ◽  
Yuping Tai ◽  
Xinzhong Li

Abstract Generally, an optical vortex lattice (OVL) is generated via the superposition of two specific vortex beams. Thus far, OVL has been successfully employed to trap atoms via the dark cores. The topological charge (TC) on each optical vortex (OV) in the lattice is only ±1. Consequently, the orbital angular momentum (OAM) on the lattice is ignored. To expand the potential applications, it is necessary to rediscover and exploit OAM. Here we propose a novel high-order OVL (HO-OVL) that combines the phase multiplication and the arbitrary mode-controllable techniques. TC on each OV in the lattice is up to 51, which generates sufficient OAM to manipulate microparticles. Thereafter, the entire lattice can be modulated to desirable arbitrary modes. Finally, yeast cells are trapped and rotated by the proposed HO-OVL. To the best of our knowledge, this is the first realization of the complex motion of microparticles via OVL. Thus, this work successfully exploits OAM on OVL, thereby revealing potential applications in particle manipulation and optical tweezers.


2011 ◽  
Vol 11 (13) ◽  
pp. 10-10 ◽  
Author(s):  
L. Kaunitz ◽  
A. Fracasso ◽  
D. Melcher
Keyword(s):  

Robotica ◽  
2001 ◽  
Vol 19 (1) ◽  
pp. 87-91 ◽  
Author(s):  
M. Guihard ◽  
P. Gorce

The aim of this paper is to propose a bipedal structure able to follow high acceleration movements. The vertical jump of a human has been chosen as input (coming from experiments) to validate the controller design as it is one of the most complex motion. The study concerns the low level of the biped control that is to say the control design of one leg made of three rigid bodies, each of them moved by a pneumatic actuator. An analogy between a pneumatic actuator and a physiological muscle is first proposed. A dynamic model of the leg is then presented decoupling the dynamic effects of the skeletal (as interactions between segments) from the dynamic effects of the muscles involved. The controller is based on the nonlinear theory (taking into account the actuator and the mechanical models), it ensures a dynamic tracking of position and force. Its originality lays in the consideration of impedance behaviour at each joint during free and constrained tasks. It leads to asymptotically stable (Popov criteria) control laws which are continuous between contact and non-contact phases enabling real-time computations. The simulation results clearly show the tracking of position and forces during the whole jump cycle.


2001 ◽  
Author(s):  
Som Chattopadhyay

Abstract Positioning accuracy within the range of nanometers is required for high precision machining applications. The implementation of such a range is difficult through the slides because of (a) irregular nature of friction at the slider-guideway interface, and (b) complex motion characteristic at very low speeds. The complexity arises due to the local deformation at the interface prior to breakaway, which is known as microdynamics. In this work prior experimental results exhibiting microdynamics have been appraised, and mathematical model developed to understand this behavior.


2018 ◽  
Vol 184 ◽  
pp. 01009
Author(s):  
Florina-Carmen Ciornei ◽  
Stelian Alaci ◽  
Sorinel-Toderas Siretean ◽  
Mariana-Catalina Ciornei ◽  
Ioan-Bogdan Dragoi ◽  
...  

The complex motion from a point contact has as consequence the occurrence of a friction torsor within both spinning and rolling friction exist. Additionally, recent researches showed that the two friction moments, spinning and rolling torques, are not proportional to the normal force. Here, the power law dependency is accepted and therefore, besides the coefficients of spinning and rolling friction, the exponents from the relations friction torque-normal force should be first determined. The paper proposes as method for finding the four parameters the use of the inclined plane principle. The acceleration of a revolution body in descending motion on the inclined plane is found for four different values of the tilting angle and a system of four equations is obtained. The detailed procedure of finding the solutions of the system is presented in the present paper.


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