scholarly journals A position control-based approach to haptic rendering of stiff objects using piece-wise linear model

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110648
Author(s):  
Yang Wang ◽  
Lei Feng ◽  
Kjell Andersson
Keyword(s):  
Linear Model ◽  
Position Control ◽  
Interaction Force ◽  
Haptic Rendering ◽  
Performance Comparison ◽  
Parallel Structure ◽  
Comparison Study ◽  
Simulation Based ◽  
Previous Solution ◽  
Linearized Model

In traditional force rendering approaches, it is quite popular to model a virtual stiff wall as a spring-damper system to compute the interaction force, which can easily lead to unstable behavior. In this paper, we present an approach to ensure no penetration into the wall by position control. The approach approximates the nonlinear model of a 6-DOF parallel-structure haptic device by a piece-wise linear model to improve the performance compared with a controller designed from a one-point linearized model in haptic rendering. A simulation-based performance comparison study shows that the new controller can render higher stiffness than the previous solution.

Comparison Study of Membrane Flapping Wing Based on Mooney-Rivlin Model and Linear Model

2013 ◽  
Vol 753-755 ◽  
pp. 1842-1845
Author(s):  
Chun Jin Yu
Keyword(s):  
Linear Model ◽  
Flapping Wing ◽  
Comparison Study ◽  
Maximum Deformation

The maximum deformation and stress are compared based on Mooney-Rivlin Model and Linear Model for flapping wing. One flapping cycle was divided into twelve segments, and maximum deformation and stress were calculated in each segment. The results show that max deformation and stress all occur at the beginning of downstroke, the max deformation adopted Mooney-Rivlin model is 25 percent of the max deformation adopted the linear model, and the max stress adopted Mooney-Rivlin model is only 0.37 percent of the max stress adopted the linear model. Mooney-Rivlin Material is very suitable for the membrane flapping wing.

Study of gyrotron synchronization by an external harmonic signal based on a modified quasi-linear theory

2021 ◽  
Vol 29 (6) ◽  
pp. 905-914
Author(s):  
Nataliia Grigorieva ◽  
Keyword(s):  
Linear Model ◽  
Harmonic Signal ◽  
Rational Functions ◽  
Maximum Efficiency ◽  
External Signal ◽  
Excitation Mode ◽  
Microwave Electronics ◽  
Simulation Based ◽  
Hard Excitation ◽  
Synchronization Pattern

Topic. The paper is devoted to the study of synchronization of a gyrotron by an external harmonic signal. A theoretical study of gyrotron synchronization processes by means of a computational experiment based on certain traditional models of microwave electronics does not provide a complete description of the synchronization pattern. Therefore, the goal of the paper is to develop a modified quasi-linear model based on an approximation of the electron susceptibility by rational functions. Methods. The developed model allows for bifurcation analysis of synchronization processes. On its basis, stationary states are determined and their stability analysis is carried out. The results are in good agreement with numerical simulation based on the non-stationary theory of a gyrotron with a fixed Gaussian high-frequency field structure. Results and discussion. Resonance curves and synchronization bounds are built on the plane of parameters “amplitude – frequency of external signal”. The case where the gyrotron is in the hard excitation mode is considered, since the maximum efficiency is usually achieved in the hard excitation mode. In general, the results are in qualitative agreement with the picture described earlier for a simpler quasi-linear model of a oscillator with hard excitation, in the case of a sufficiently strong phase nonlinearity.

scholarly journals A Joint-space Position Control-based Approach to Haptic Rendering of Stiff Objects using Gain Scheduling

2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Yang Wang ◽  
Lei Feng ◽  
Kjell Andersson
Keyword(s):  
Simulation Model ◽  
Position Control ◽  
Gain Scheduling ◽  
Joint Space ◽  
Haptic Rendering ◽  
Smooth Transition ◽  
Position Controller ◽  
Detailed Simulation ◽  
Stability Issues ◽  
Computing Models

AbstractHaptic rendering often deals with interactions between stiff objects. A traditional way of force computing models the interaction using a spring-damper system, which suffers from stability issues when the desired stiffness is high. Instead of computing a force, this paper continues to explore shifting the focus to rendering an interaction with no penetration, which can be accomplished by using a position controller in the joint space using the encoders as feedback directly. In order to make this approach easily adaptable to any device, an alternative way to model the dynamics of the device is also presented, which is to linearize a detailed simulation model. As a family of linearized models is used to approximate the full dynamic model of the system, it is important to have a smooth transition between multiple sets of controller gains generated based on these models. Gain scheduling is introduced to improve the performance in certain areas and a comparison among three controllers is conducted in a simulation setup.

Electrochemical performance comparison study of ternary RGO/ß-Ni(OH)2-CeO2 nanocomposite prepared from hydrothermal and solid-state methods for supercapacitors

2021 ◽  
Vol 12 (1) ◽  
pp. 015016
Author(s):  
Sreenivasa Kumar Godlaveeti ◽  
Sravani Jangiti ◽  
Debasrita Bharatiya ◽  
Adinarayana Reddy Somala ◽  
Siva Sankar Sana ◽  
...  
Keyword(s):  
Solid State ◽  
Electrochemical Performance ◽  
Performance Comparison ◽  
Comparison Study
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