A Coupled Two Degree of Freedom Model for Nano/Micromirrors Under van der Waals Force

2012 ◽  
Author(s):  
Hamid Moeenfard ◽  
Ali Darvishian ◽  
Mohammad Taghi Ahmadian
Keyword(s):  
Coupled Model ◽  
Bending Stiffness ◽  
Degree Of Freedom ◽  
Instability Mode ◽  
Equilibrium Equations ◽  
Bending Mode ◽  
Minimum Potential ◽  
Vdw Force ◽  
Torsion Stiffness ◽  
Two Degree Of Freedom

The current paper presents a two degree of freedom model for the problem of nano/micromirrors under the effect of vdW force. Energy method, the principal of minimum potential energy is employed for finding the equilibrium equations governing the deflection and the rotation of the nano/micromirror. Then using the implicit function theorem, a coupled bending-torsion model is presented for the pull-in characteristics of nano/micromirrors under vdW force and the concept of instability mode is introduced. It is observed that with increasing the ratio of the bending stiffness to the torsion stiffness, the dominant instability mode changes from bending mode to the torsion mode. It is shown that when the bending stiffness of the system is relatively low, the equilibrium point of a one degree of freedom torsion model considerably deviates from that of coupled model. The presented model in this paper can be used for safe and stable design of nano/micromirrors under vdW force.

Coupling Effects Between Torsion and Bending in Torsional Micromirrors Under Capillary Forces

2011 ◽  
Author(s):  
Ali Darvishian ◽  
Hamid Moeenfard ◽  
Mohammad Taghi Ahmadian
Keyword(s):  
Coupling Effect ◽  
Coupled Model ◽  
Capillary Forces ◽  
Bending Stiffness ◽  
Minimum Potential Energy ◽  
Implicit Functions ◽  
Bending Effect ◽  
Bending Mode ◽  
Minimum Potential ◽  
Torsion Stiffness

In the current paper, a general theoretical model for the problem of micromirrors under the effect of capillary forces is presented. The presented model considers the coupling effect between torsion and bending of the torsion beams supporting the micromirror. First, the energy method, the principal of minimum potential energy is utilized for finding the equations governing the micromirror rotation and its deflection. Then using the implicit functions theorem, the equations governing the pull-in angle and pull-in displacement of the micromirror is derived. The results, shows that ignoring the bending effect in micromirrors under the effect of capillary forces, can cause a significant (up to several hundred percents) underestimation of the pull-in angle. It is observed that with increasing the ratio of the bending stiffness to the torsion stiffness, the dominant instability mode changes from bending mode to the torsion mode. It is shown that when the bending stiffness of the system is relatively low, the equilibrium point of a one degree of freedom torsion model considerably deviates from that of coupled model. The presented model in this paper can be used for safe and stable design of micromirrors under capillary force.

Intuitive Physical Human-Robot Interaction using an Underactuated Redundant Manipulator with Complete Spatial Rotational Capabilities

2021 ◽  
pp. 1-15
Author(s):  
Julien-Mathieu Audet ◽  
Clement Gosselin
Keyword(s):  
Human Robot Interaction ◽  
Degree Of Freedom ◽  
Static Equilibrium ◽  
Rotational Axis ◽  
Redundant Manipulator ◽  
Equilibrium Equations ◽  
Robot Interaction ◽  
Experimental Validations ◽  
Spatial Rotations ◽  
Two Degree Of Freedom

Abstract In this paper, the concept of underactuated redundancy is presented using a novel spatial two-degree-of-freedom (2-DoF) gravity balanced rotational manipulator, composed of movable counterweights. The proposed kinematic arrangement makes it possible to intuitively manipulate a payload undergoing 3-DoF spatial rotations by adding a third rotational axis oriented in the direction of gravity. The static equilibrium equations of the 2-DoF architecture are first described in order to provide the required configuration of the counterweights for a statically balanced mechanism. A method for calibrating the mechanism, which establishes the coefficients of the static equilibrium equations, is also presented. In order to both translate and rotate the payload during manipulation, the rotational manipulator is mounted on an existing translational manipulator. Experimental validations of both systems are presented to demonstrate the intuitive and responsive behaviour of the manipulators during physical human-robot interactions.

Sign in / Sign up

Export Citation Format

Share Document