On the Global Behavior of a Geometric PDAV Controller by Means of a Geometrically Exact Linearization

2021 ◽  
Author(s):  
Michalis Ramp ◽  
Evangelos Papadopoulos
Keyword(s):  
Angular Velocity ◽  
Rigid Body ◽  
High Frequency ◽  
Vector Fields ◽  
Closed Loop ◽  
Control Engineer ◽  
Global Behavior ◽  
Exact Linearization ◽  
Complex Motion ◽  
Simulation Techniques

Abstract A complex motion encountered in a number of robotic, industrial and defense applications is the motion of a rigid body when one of its body-fixed axes tracks a desired Pointing Direction while it rotates at high Angular Velocity around the pointing direction (PDAV); during this motion high frequency precession/nutation oscillations arise. This work analyzes the global/local closed-loop behavior induced by a developed geometric, PDAV controller and studies the high frequency precession/nutation oscillations that characterize PDAV motions. This is done via geometrically-exact linearization and via simulation techniques that amount to charting the smooth closed-loop vector fields on the manifold. A method to quickly estimate the frequency of the precession/nutation oscillations is developed and can be used for sizing actuators. A thorough understanding of the behavior of the closed-loop flow induced by the PDAV controller is achieved, allowing the control engineer to anticipate/have a rough estimate of the system closed-loop response.

Stability of a Rigid Body With an Oscillating Particle: An Application of MACSYMA

1985 ◽  
Vol 52 (3) ◽  
pp. 686-692 ◽  
Author(s):  
L. A. Month ◽  
R. H. Rand
Keyword(s):  
Angular Velocity ◽  
Rigid Body ◽  
Classical Problem ◽  
Moment Of Inertia ◽  
Model Parameters ◽  
Stability Chart ◽  
The Stability ◽  
Transition Curves ◽  
Minimum Moment ◽  
Small Angular Velocity

This problem is a generalization of the classical problem of the stability of a spinning rigid body. We obtain the stability chart by using: (i) the computer algebra system MACSYMA in conjunction with a perturbation method, and (ii) numerical integration based on Floquet theory. We show that the form of the stability chart is different for each of the three cases in which the spin axis is the minimum, maximum, or middle principal moment of inertia axis. In particular, a rotation with arbitrarily small angular velocity about the maximum moment of inertia axis can be made unstable by appropriately choosing the model parameters. In contrast, a rotation about the minimum moment of inertia axis is always stable for a sufficiently small angular velocity. The MACSYMA program, which we used to obtain the transition curves, is included in the Appendix.

The Design and Simulation of Three-Phase PWM Converter

2013 ◽  
Vol 321-324 ◽  
pp. 917-920
Author(s):  
Guang Ya Liu ◽  
Xiao Song Li
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Voltage Source ◽  
Pwm Rectifier ◽  
Phase Voltage ◽  
Pwm Converter ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Three Phase ◽  
Loop Control System

Three-phase voltage source PWM rectifier generally adopts double closed loop control system. According to the high frequency characteristic of three-phase voltage source PWM rectifier, this paper put forward the setting method of current inner ring regulator and voltage outer ring regulator PI parameter. Finally, it is verified by simulation.

On the angular velocity of a rigid body: Matrix and vector representations

2014 ◽  
Vol 45 ◽  
pp. 123-132
Author(s):  
J. Jesús Cervantes-Sánchez ◽  
José M. Rico-Martínez ◽  
Victor Hugo Pérez-Muñoz
Keyword(s):  
Angular Velocity ◽  
Rigid Body ◽  
Vector Representations

A High-Frequency Inverter Based on Double Closed-Loop Control

2012 ◽  
Vol 241-244 ◽  
pp. 509-512
Author(s):  
Lin Yang ◽  
Gen Wang Liu
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Control Structure ◽  
Dynamic Performance ◽  
Current Loop ◽  
Closed Loop Control ◽  
Voltage Waveform ◽  
Loop Control ◽  
Static Performance ◽  
Frequency Inverter

In order to improve the dynamic performance of inverter and the output voltage waveform quality, the double-loop control combination with internal current loop and external voltage loop is introduced. The inner loop is used for improving the dynamic performance of the system and rapidly eliminating the effects of load disturbance; the outer loop is used for improving static performance of the system. In the end, MATLAB / Simulink is carried out to build the system model and prove the feasibility of the dual closed-loop control structure in this paper.

scholarly journals Open-closed Iterative Learning Control Algorithm for Exoskeleton Rehabilitation Purposes

2019 ◽  
Vol 292 ◽  
pp. 01010
Author(s):  
Mihailo Lazarević ◽  
Nikola Živković ◽  
Darko Radojević
Keyword(s):  
Iterative Learning Control ◽  
Control Algorithm ◽  
Closed Loop ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Control Law ◽  
Exact Linearization ◽  
Outer Loop ◽  
Control Scheme

The paper designs an appropriate iterative learning control (ILC) algorithm based on the trajectory characteristics of upper exosk el eton robotic system. The procedure of mathematical modelling of an exoskeleton system for rehabilitation is given and synthesis of a control law with two loops. First (inner) loop represents exact linearization of a given system, and the second (outer) loop is synthesis of a iterative learning control law which consists of two loops, open and closed loop. In open loop ILC sgnPDD2 is applied, while in feedback classical PD control law is used. Finally, a simulation example is presented to illustrate the feasibility and effectiveness of the proposed advanced open-closed iterative learning control scheme.

scholarly journals Effect of Closed-Loop Vibration Stimulation on Heart Rhythm during Naps

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4136 ◽  
Author(s):  
Sang Ho Choi ◽  
Heenam Yoon ◽  
Hyung Won Jin ◽  
Hyun Bin Kwon ◽  
Seong Min Oh ◽  
...  
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Low Frequency ◽  
Heart Rhythm ◽  
Quality Of Sleep ◽  
Stimulation Condition ◽  
Term Basis ◽  
Stimulation System

Sleep plays a primary function for health and sustains physical and cognitive performance. Although various stimulation systems for enhancing sleep have been developed, they are difficult to use on a long-term basis. This paper proposes a novel stimulation system and confirms its feasibility for sleep. Specifically, in this study, a closed-loop vibration stimulation system that detects the heart rate (HR) and applies −n% stimulus beats per minute (BPM) computed on the basis of the previous 5 min of HR data was developed. Ten subjects participated in the evaluation experiment, in which they took a nap for approximately 90 min. The experiment comprised one baseline and three stimulation conditions. HR variability analysis showed that the normalized low frequency (LF) and LF/high frequency (HF) parameters significantly decreased compared to the baseline condition, while the normalized HF parameter significantly increased under the −3% stimulation condition. In addition, the HR density around the stimulus BPM significantly increased under the −3% stimulation condition. The results confirm that the proposed stimulation system could influence heart rhythm and stabilize the autonomic nervous system. This study thus provides a new stimulation approach to enhance the quality of sleep and has the potential for enhancing health levels through sleep manipulation.

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