Nonlinear modeling for a class of nano-robotic systems using piezoelectric stick-slip actuators

Author(s):  
Tianming Lu ◽  
Mokrane Boudaoud ◽  
David Heriban ◽  
Stephane Regnier
1994 ◽  
Vol 47 (7) ◽  
pp. 227-253 ◽  
Author(s):  
R. A. Ibrahim

This part provides a comprehensive account of the main theorems and mechanisms developed in the literature concerning friction-induced noise and vibration. Some of these mechanisms are based on experimental investigations for classical models. Bilinear and nonlinear dynamical models have been considered to explain such friction phenomena as stick-slip, chatter, squeal, and chaos. Nonlinear modeling includes two types of nonlinearities which differ from those encountered in structural dynamics. These nonlinearities, in addition to the observed uncertainty of friction between sliding surfaces, form a formidable difficulty in developing accurate and reliable modeling. They include the inherent nonlinearity of contact forces (eg, Hertzian contact), and the nonlinear relationship between friction and sliding relative velocity. Research activities in this area are a mixture of theoretical, numerical, and experimental investigations. Theoretical investigations are prevailed by deterministic analysis with few attempts of stochastic treatment. The models include classical and practical engineering models such as the mass-spring model sliding on a running belt or on a surface with Hertzian contact, a pin sliding on a rotating disk, beams with friction boundaries, turbine blades, water-lubricated bearings, wheel-rail systems, disc brake systems and machine cutting tools. There is a strong need for further research to promote our understanding of the various friction mechanisms and to provide designers of sliding components with better guidelines to minimize the deteriorating effects of friction.


Robotica ◽  
2009 ◽  
Vol 28 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Nidal Farhat ◽  
Vicente Mata ◽  
Álvaro Page ◽  
Miguel Díaz-Rodríguez

SUMMARYDynamic simulation in robotic systems can be considered as a useful tool not only for the design of both mechanical and control systems, but also for planning the tasks of robotic systems. Usually, the dynamic model suffers from discontinuities in some parts of it, such as the use of Coulomb friction model and the contact problem. These discontinuities could lead to stiff differential equations in the simulation process. In this paper, we present an algorithm that solves the discontinuity problem of the Coulomb friction model without applying any normalization. It consists of the application of an external switch that divides the integration interval into subintervals, the calculation of the friction force in the stick phase, and further improvements that enhance its stability. This algorithm can be implemented directly in the available commercial integration routines with event-detecting capability. Results are shown by a simulation process of a simple 1-DoF oscillator and a 3-DoF parallel robot prototype considering Coulomb friction in its joints. Both simulations show that the stiffness problem has been solved. This algorithm is presented in the form of a flowchart that can be extended to solve other types of discontinuity.


Author(s):  
Geoffrey W Rodgers ◽  
Oliver Mesnil ◽  
Jose Chanchi ◽  
Gregory A. MacRae ◽  
Charles Clifton ◽  
...  

The Sliding Hinge Joint (SHJ) is an Asymmetric Friction Connection (AFC) developed to create a repeatable, efficient means of dissipating seismic response energy and reducing structural damage without yielding of the structural frame elements. Testing has demonstrated stable efficient hysteretic behaviour. However, it is necessary to fully characterise their dynamic behaviour including any less stable aspects observed in the response of these devices for selected materials. This observed behaviour may reduce device force and energy dissipation, creating an influence on the overall structure that should be fully understood and accounted for in design. This research models the hysteretic behaviour of a SHJ with a zinc anti-corrosion coating that demonstrates less than fully stable experimental dynamic behaviour in contrast to many other SHJ material choices. The model developed uses a stick-slip mechanism based on a variable friction coefficient to capture the observed dynamics with an overall Menegotto-Pinto dynamic hysteretic model. The overall results show how the model may be realistically extended to a more general model that captures observed non-linear dynamics in these and similar friction devices, and yield new insight and design tools for use with these devices.


2019 ◽  
Vol 285 ◽  
pp. 258-268 ◽  
Author(s):  
R. Oubellil ◽  
A. Voda ◽  
M. Boudaoud ◽  
S. Régnier

ISRN Robotics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Nadya Ghrab ◽  
Hichem Kallel

A comparative study between static and dynamic neural networks for robotic systems control is considered. So, two approaches of neural robot control were selected, exposed, and compared. One uses a static neural network; the other uses a dynamic neural network. Both compensate the nonlinear modeling and uncertainties of robotic systems. The first approach is direct; it approximates the nonlinearities and uncertainties by a static neural network. The second approach is indirect; it uses a dynamic neural network for the identification of the robot state. The neural network weight tuning algorithms, for the two approaches, are developed based on Lyapunov theory. Simulation results show that the system response, equipped by dynamic neural network controller, has better tracking performance, has faster response time, and is more reliable to face disturbances and robotic uncertainties.


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