System Identification and Multivariate Controller Design for a Satellite Ultraquiet Isolation Technology Experiment (SUITE)

2002 ◽  
Author(s):  
Alok A. Joshi ◽  
Won-jong Kim
Keyword(s):  
Vibration Isolation ◽  
Transfer Functions ◽  
Controller Design ◽  
Input Output ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Single Input Single Output ◽  
Single Output ◽  
Single Input ◽  
Six Degree Of Freedom

A mathematical model of a six-degree-of-freedom hexapod system for vibration isolation was derived in the discrete-time domain on the basis of the experimental data obtained from a satellite. Using Box-Jenkins model structure, the transfer functions between six piezoelectric actuator input voltages and six geophone sensor output voltages are identified empirically. The 6×6 transfer function matrix is symmetric, and its off-diagonal terms indicate the coupling among different input/output channels. Though the coupling was observed among various input/output channels up to 10 Hz, the single-input single-output (SISO) controllers were designed neglecting the effect of coupling. The SISO controllers demonstrated limited performance in vibration attenuation. Using multi-input multi-output (MIMO) control techniques such as Linear Quadratic Gaussian (LQG) and H∞, high-order controllers were developed. The simulation results using these controllers obtain 33 dB, and 12 dB attenuation at 5, and 25 Hz corner frequencies, respectively.

Modeling and Multivariable Control Design Methodologies for Hexapod-Based Satellite Vibration Isolation

2004 ◽  
Vol 127 (4) ◽  
pp. 700-704 ◽  
Author(s):  
Alok Joshi ◽  
Won-jong Kim
Keyword(s):  
Vibration Isolation ◽  
Transfer Functions ◽  
Multivariable Control ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Control Techniques ◽  
Vibration Attenuation ◽  
Active Vibration ◽  
Six Degree Of Freedom ◽  
Function Matrix

A mathematical model of a six-degree-of-freedom (6-DOF) hexapod system for vibration isolation was derived in the discrete-time domain on the basis of the experimental data obtained from a satellite. Using a Box–Jenkins model structure, the transfer functions between six piezoelectric actuator input voltages and six geophone sensor output voltages were identified empirically. The 6×6 transfer function matrix is symmetric, and its off-diagonal terms indicate the coupling among different input/output channels. Various multi-input multi-output (MIMO) control techniques such as Linear Quadratic Gaussian and H∞ were proposed for active vibration isolation in the broadband up to 100 Hz. The simulation results using these controllers obtain 13 and 8 dB vibration attenuation at 25 and 35 Hz, respectively.

Active Vibration Isolation of Metrology Frames; A Modal Decoupled Control Design

2005 ◽  
Vol 127 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Marcel Heertjes ◽  
Koen de Graaff ◽  
Jan-Gerard van der Toorn
Keyword(s):  
Vibration Isolation ◽  
Isolation System ◽  
Single Input Single Output ◽  
Single Output ◽  
System A ◽  
Active Vibration ◽  
Single Input ◽  
And Performance ◽  
Six Degree Of Freedom ◽  
Active Vibration Isolation

For a six degree-of-freedom active vibration isolation system, a control strategy based on modal decoupling is proposed. This has the advantage of controlling the modal directions on a centralized single-input single-output basis. As a consequence, stability and performance can be imposed in each of the modal directions separately. An experimental demonstration is given using a dummy metrology frame. That is, a 1600 kg payload mass supported by three combined pneumatic and Lorentz controlled isolators. With this setup, two unstable modal directions resulting from a high center of gravity are stabilized without compromising performance in any of the remaining directions. In fact, performance in the remaining directions is enhanced using manual loop shaping.

Describing Functions for Scalar Information Channels Subject to Quantization and Packet Loss

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Eric Gilbertson ◽  
Franz Hover
Keyword(s):  
Packet Loss ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Single Input Single Output ◽  
Describing Functions ◽  
Single Output ◽  
Single Input ◽  
Key Steps ◽  
Binary Erasure Channel ◽  
Siso System

Many of today's robot applications depend on wireless communications, whose performance can impact the whole system. To support analysis of feedback control through limited channels, we develop describing functions (DFs) for three variations on the series interconnection of a quantizer, a binary erasure channel, and decoder for a single input single output (SISO) system. The key steps in our derivation hold when the decoder is a linear-quadratic-Gaussian (LQG)-type control, a zero-output decoder, or a hold-output decoder. We confirm the accuracy of the new formulas and provide an example showing limit cycle behavior.

Control of Exoskeletons Inspired by Fictitious Variable Gain in Human

2008 ◽  
Author(s):  
Kyoungchul Kong ◽  
Masayoshi Tomizuka
Keyword(s):  
Control System ◽  
Control Algorithm ◽  
Controller Design ◽  
Assistive Device ◽  
Single Input Single Output ◽  
Variable Gain ◽  
Single Output ◽  
Single Input ◽  
Parallel Control ◽  
The Brain

A human wearing an exoskeleton-type assistive device results in a parallel control system that includes two controllers: the human brain and a digital exoskeleton controller. Unknown and complicated characteristics of the brain dynamically interact with the exoskeleton controller which makes the controller design challenging. In this paper, the motion control system of a human is regarded as a feedback control loop that consists of a brain, muscles and the dynamics of the extended human body. The brain is modeled as a control algorithm amplified by a fictitious variable gain. The variable gain compensates for characteristic changes in the muscle and dynamics. If a human is physically impaired or subjected to demanding work, the exoskeleton should generate proper assistive forces, which is equivalent to increasing the variable gain. In this paper, a control algorithm that realizes the fictitious variable gain is designed and its performance and robustness are discussed for single-input single-output cases. The control algorithm is then verified by simulation results.

scholarly journals Design of Self-Tuning Minimum Effort Active Noise Control with Feedback Inclusion Architecture

2009 ◽  
Vol 28 (3) ◽  
pp. 205-215 ◽  
Author(s):  
R. K. Raja Ahmad ◽  
M. O. Tokhi
Keyword(s):  
Noise Control ◽  
Transfer Functions ◽  
Controller Design ◽  
Active Noise Control ◽  
The Self ◽  
Recursive Least Squares ◽  
Single Input Single Output ◽  
Single Output ◽  
Active Noise ◽  
Self Tuning

This paper presents the development of a self-tuning controller design of minimum effort active noise control (ANC) for feedforward single-input single-output (SISO) architecture which includes the feedback acoustic path in the controller formulation. The controller design law is derived for suitable self-tuning implementation and the self-tuning controller is evaluated in a realistically constructed ANC simulation environment. The self-tuning controller design involves a two-stage identification process where the controller is replaced by a switch. This switch is closed and opened in sequence generating two transfer functions which are then used in constructing the controller specified by a minimum effort control law. The implementation requires an estimate of the secondary path transfer function which can be identified either online or offline. The controller design and implementation are evaluated in terms of the level of cancellation at the observer through simulation studies for various values of modified effort weighting parameter in the range 0 ≤ γ ≤ 1. It was found that the optimal controller designed using this technique which is constrained only by the accuracy of the two models identified using recursive least squares algorithm, yields good cancellation level.

Series-Parallel and Parallel Identification Schemes for a Class of Continuous Nonlinear Systems

1977 ◽  
Vol 99 (2) ◽  
pp. 137-140
Author(s):  
Masayoshi Tomizuka
Keyword(s):  
Identification Algorithm ◽  
Input Output ◽  
Single Input Single Output ◽  
Identification Schemes ◽  
Linear Dynamic ◽  
Single Output ◽  
Single Input ◽  
Static Part ◽  
Nonlinear Static ◽  
The Stability

This technical brief deals with the identification of a single-input, single-output nonlinear system which is composed of a nonlinear static part and a linear dynamic part. A series-parallel identification algorithm and a parallel identification algorithm are presented; they require the input, output, and the order of the linear dynamic portion of the system. The stability of the algorithms is assured by Popov’s hyperstability theorem. The effectiveness of the identification schemes developed is demonstrated by computer simulation.

Assessment of a Robust Algorithm for the Detection and Diagnosis of Additive Faults

2006 ◽  
Author(s):  
Vasilis K. Dertimanis ◽  
Dimitris V. Koulocheris ◽  
Constantinos N. Spentzas
Keyword(s):  
System Identification ◽  
Input Output ◽  
Detection Problem ◽  
Identification Procedure ◽  
Single Input Single Output ◽  
Single Output ◽  
Robustness To Noise ◽  
Single Input ◽  
Detection And Diagnosis ◽  
Identification Techniques

This paper addresses the problem of additive faults (such as input/output sensor and actuator) in a dynamic system, from the view of system identification techniques. The relation between the residuals of the model–based fault diagnosis and the innovations of the system identification procedure is implemented and corresponding algorithms are extracted for the tracking of additive faults, while robustness to noise and disturbances is issued. The study is initiated using single input-single output models and extended to multiple inputs-multiple outputs structures. Furthermore, the detection problem of additive faults for systems with unobservable excitation is examined.

Sign in / Sign up

Export Citation Format

Share Document