On Time Delay in Noncolocated Control of Flexible Mechanical Systems

A new method is presented for noncolocated control of flexible mechanical systems. The destabilizing effect of noncolocation of sensors and actuators is eliminated through introduction of specific time delay block(s) in the control system. The time delay constants in those blocks depend on the system eigenstructure. For a given flexible mechanical system, if there exists a time delay relation, the system response at one point can be exactly predicted from the vibration measurement at other point(s) of the system. In this case all stabilizing controllers from colocated control can be directly used. The time delay theory is verified by experiments on noncolocated control of a translating string.

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Modal Control of Underactuated Systems

Volume 5: 22nd International Conference on Design Theory and Methodology; Special Conference on Mechanical Vibration and Noise ◽

10.1115/detc2010-28354 ◽

2010 ◽

Author(s):

D. Dane Quinn ◽

Vineel Mallela

Keyword(s):

Control System ◽

Mechanical System ◽

Mechanical Systems ◽

Degree Of Freedom ◽

Feedback Gain ◽

Underactuated Systems ◽

Modal Control ◽

Underactuated Mechanical Systems ◽

Sensors And Actuators ◽

Sensor Actuator

This work addresses the modal control of underactuated mechanical systems, whereby the number of actuators is less than the degree-of-freedom of the underlying mechanical system. The performance of the control system depends on the structure of the feedback gain matrix, that is, the coupling between sensors and actuators. This coupling is often not arbitrary, but the topology of the sensor-actuator network can be a fixed constraint of the control system. This work examines the influence of this structure on the performance of the overlying control system.

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The Control of Vibration Transmissibility Using an Electrodynamic Actuator –Close-Loop Solution

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.436.166 ◽

2013 ◽

Vol 436 ◽

pp. 166-173

Author(s):

A. Mihaela Mîţiu ◽

Daniel Constantin Comeagă ◽

Octavian G. Donţu

Keyword(s):

Mathematical Model ◽

Control System ◽

Mechanical System ◽

Closed Loop ◽

Mechanical Systems ◽

Vibration Transmissibility ◽

Technical Solutions ◽

The Mathematical Model

In this paper are presented some aspects of transmissibility control of mechanical systems with 1 DOF so that the effects of vibration on their action to be minimized. Some technical solutions that can be used for this purpose is analyzed. Starting from the mathematical model of an electro-mechanical system with 1 DOF, are identified the parameters which influence the effectiveness of the transmissibility control system using an electrodynamic actuator who work in "closed loop".

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An Amoeboid Locomotion That Exploits Real-Time Tunable Springs and Law of Conservation of Protoplasmic Mass

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2008.p0449 ◽

2008 ◽

Vol 20 (3) ◽

pp. 449-455

Author(s):

Takuya Umedachi ◽

◽

Taichi Kitamura ◽

Akio Ishiguro

Keyword(s):

Control System ◽

Mechanical System ◽

Real Time ◽

Mechanical Systems ◽

The Body ◽

Amoeboid Locomotion ◽

Central Controller ◽

Tightly Coupled ◽

Computational Offloading ◽

Embodied Agent

The control and mechanical systems of an embodied agent should be tightly coupled so as to emerge useful functionalities such as adaptivity. This indicates that the mechanical system as well as the control system should be responsible for a certain amount of computation for generating the behavior. However, there still leaves much to be understood about how such “computational offloading” from the control system to the mechanical system can be achieved. In order to intensively investigate this, here we particularly focus on the “softness” of the body, and show how the computational offloading derived from this property is exploited to simplify the control system and to increase the degree of adaptivity. To this end, we employ a two-dimensional amoeboid robot as a practical example, consisting of incompressive fluid (i.e. protoplasm) covered with an outer skin composed of a network of real-time tunable springs. Preliminary simulation results show that the exploitation of the “long-distant interaction” stemming from “the law of conservation of protoplasmic mass” allows us to simplify the control mechanism; and that adaptive amoeboid locomotion can be realized without the need of a central controller. The results obtained are expected to shed light on how control and mechanical systems should be coupled, and what the “brain-body-interaction” carefully designed brings to the resulting behavior.

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Noncolocated Control of a Damped String Using Time Delay

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2897752 ◽

1992 ◽

Vol 114 (4) ◽

pp. 736-740 ◽

Cited By ~ 20

Author(s):

B. Yang

Keyword(s):

Control System ◽

Time Delay ◽

Laplace Transform ◽

Feedback Loop ◽

Transform Domain ◽

Flexible Systems ◽

Specific Time ◽

Bode Plot ◽

Control Gain ◽

The Laplace Transform

Recent research studies noncolocated control of flexible mechanical systems using time delay. The developments are limited to undamped flexible systems; damped flexible systems have not been considered. This paper investigates noncolocated vibration control of a viscously damped string using time delay. The control system is formulated in the Laplace transform domain. Based on the understanding of the system eigenstructure, a modified Bode plot of the feedback controller is introduced in a design region. The Bode plot designed, along with a specific time delay in the feedback loop, proper sensor and actuator positions, and proper control gain, guarantees stabilization of vibration of the damped string.

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Study on Integral-Separate PID Improved Predictive Control for Electro-Hydraulic Control System of Strip Steel CPC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.422.250 ◽

2011 ◽

Vol 422 ◽

pp. 250-256 ◽

Cited By ~ 1

Author(s):

Xiao Hua Ye ◽

Yu Wan Cen ◽

Jing Jie Ye

Keyword(s):

Mathematical Model ◽

Control System ◽

Time Delay ◽

Predictive Control ◽

Control Algorithm ◽

Structural Parameters ◽

System Response ◽

Hydraulic Control ◽

Strip Steel ◽

Hydraulic Control System

As electro-hydraulic control system of strip steel CPC has some special characteristics, such as strong nonlinear, changes in structural parameters, serious time-delay and the very difficultly of establishing accurate mathematical model, the integral-separate PID improved predictive control algorithm was proposed on the basis of the new mathematical model. Firstly, the integral-separate PID algorithm was used to make system asymptotic stability and reduce overshoot of system. Secondly, the predictive control algorithm was proposed, error feedback correction model was improved, and predictive control signal was optimized with rolling method. Finally, the system was simulated and analyzed in noise and pulse disturbance. The simulation results show that this algorithm can effectively improved abilities of anti-noise and anti-load disturbance, increases robustness and tracking capability of strip steel CPC system; furthermore, it can improved speed of system response and decrease time-delay and overshoot of system. Therefore, this algorithm can well meet the need of electro-hydraulic control system for strip steel CPC system.

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