599 research outputs found
A survey on gain-scheduled control and filtering for parameter-varying systems
Copyright © 2014 Guoliang Wei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This paper presents an overview of the recent developments in the gain-scheduled control and filtering problems for the parameter-varying systems. First of all, we recall several important algorithms suitable for gain-scheduling method including gain-scheduled proportional-integral derivative (PID) control, H 2, H ∞ and mixed H 2 / H ∞ gain-scheduling methods as well as fuzzy gain-scheduling techniques. Secondly, various important parameter-varying system models are reviewed, for which gain-scheduled control and filtering issues are usually dealt with. In particular, in view of the randomly occurring phenomena with time-varying probability distributions, some results of our recent work based on the probability-dependent gain-scheduling methods are reviewed. Furthermore, some latest progress in this area is discussed. Finally, conclusions are drawn and several potential future research directions are outlined.The National Natural Science Foundation of China under Grants 61074016, 61374039, 61304010, and 61329301; the Natural Science Foundation of Jiangsu Province of China under Grant BK20130766; the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning; the Program for New Century Excellent Talents in University under Grant NCET-11-1051, the Leverhulme Trust of the U.K., the Alexander von Humboldt Foundation of Germany
ADAPTIVE GRAVITY BALANCING ARM SYSTEMS
Upadhyay, Harshal. M.S.M.E., Purdue University, May 2016. Adaptive Gravity-Balancing Arm Systems. Major Professor: Justin Seipel, School of Mechanical Engineering
Variable stiffness control for oscillation damping
In this paper a model-free approach for damping control of Variable Stiffness Actuators is proposed. The idea is to take advantage of the possibility to change the stiffness of the actuators in controlling the damping. The problem of minimizing the terminal energy for a one degree of freedom spring-mass model with controlled stiffness is first considered. The optimal bang-bang control law uses a maximum stiffness when the link gets away from the desired position, i.e. the link velocity is decreasing, and a minimum one when the link is going towards it, i.e. the link velocity is increasing. Based on Lyapunov stability theorems the obtained law has been proved to be stable for a multi-DoF system. Finally, the proposed control law has been tested and validated through experimental tests
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Test act system description
The engineering and fabrication of the test ACT system, produced in the third program element of the IAAC Project is documented. The system incorporates pitch-augmented stability and wing-load alleviation, plus full authority fly-by-wire control of the elevators. The pitch-augmented stability is designed to have reliability sufficient to allow flight with neutral or negative inherent longitudinal stability
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Development of adaptive transducer based on biological sensory mechanism
textAn adaptive sensor concept and prototype has been developed based on a
sensing element which is analogous to and inspired by the arrangement of outer hair
cells and inner hair cells between the basilar membrane and tectorial membrane
which form the organ of corti in mammalian cochlea. The bio-inspired design was
supported by development of a bond graph model of the electromotility (active response)
of outer hair cells. Outer hair cells perform like actuators and simulation
results using this model are compared with physiological data found in the literature
to verify its characteristic response. Insight gained from the model is used to
develop a sensor structure analogous to the organ of corti and designed to measure
acceleration. A piezoelectric bimorph was selected as the transducer basis, and a
bond graph model of the bimorph in an accelerometer configuration was formulated
to aid control design and simulation.
There is no published data regarding the type of information transmitted
among the inner hair cells, outer hair cells, and brain. Consequently, a controller
intended to adjust the adaptation process similar to what might exist in the cochlear
system has been developed for the sensor and based on a model referenced adaptive
control algorithm. Simulations verify that the algorithm can successfully control
and enhance performance of the sensor.
Practicability of the design is evaluated by a series of experiments on a
prototype. This study focused on using a controller structure that was programmed,
implemented, and tested using programmable logic based on FPGA technology.
The experiments evaluated how well the adaptive sensor could meet a specified
performance requirement. Implementation issues that arise, such as the need for
differentiators in the adaptive controller or internal propagation of vibration within
the sensor structure, hinder the tuning ability. Nevertheless, the trends indicate
that the algorithm can meet the desired performance if certain limitations can be
overcome. Finally, recommendations have been made for expansion of the research
in such fields as an alternative structure for tuning, sensor networking, and reference
sensor configuration.Mechanical Engineerin
The programmable spring: towards physical emulators of mechanical systems
The way motion is generated and controlled in robotics has traditionally been based on a philosophy of rigidity, where movements are tightly controlled and external influences are
ironed out. More recent research into autonomous robots, biological actuation and human machine interaction has uncovered the value of compliant mechanisms in both aiding the production of effective, adaptive and efficient behaviour, and increasing the margins for safety in machines that operate alongside people. Various actuation methods have previously been proposed that allow robotic systems to exploit rather than avoid the influences of external perturbations, but many of these devices can be complex and costly to engineer, and are often task specific.
This thesis documents the development of a general purpose modular actuator that can emulate the behaviour of various spring damping systems. It builds on some of the work done to produce reliable force controlled electronic actuators by developing a low cost implementation of an existing force actuator, and combining it with a novel high level control structure running in software on an embedded microcontroller. The actuator hardware with its embedded software results in a compact modular device capable of approximating the behaviour of various mechanical systems and actuation devices. Specifying these behaviours is achieved with an intuitive user interface and a control system based on a concept called profile groups. Profile group configurations that specify complex mechanical behaviours can be rapidly designed and the resulting configurations downloaded for a device to emulate.
The novel control system and intuitive user interface developed to facilitate the rapid prototyping of mechanical behaviours are explained in detail. Two prototype devices are demonstrated emulating a number of mechanical systems and the results are compared to mechanical counterparts. Performance issues are discussed and some solutions proposed alongside general improvements to the control system. The applications beyond robotics are also explored
Pneumatic motion control systems for modular robots
This thesis describes a research study in the design,
implementation, evaluation and commercialisation of
pneumatic motion control systems for modular robots. The
research programme was conducted as part of a collaborative
study, sponsored by the Science and Engineering Research
Council, between Loughborough University and Martonair (UK)
Limited.
Microprocessor based motion control strategies have been
used to produce low cost pneumatic servo-drives which can be
used for 'point-to-point' positioning of payloads. Software
based realtime control strategies have evolved which
accomplish servo-controlled positioning while compensating
for drive system non-linearities and time delays. The
application of novel compensation techniques has resulted in
a significant improvement in both the static and dynamic
performance of the drive.
A theoretical foundation is presented based on a
linearised model of a pneumatic actuator, servo-valve, and
load system. The thesis describes the design and evolution
of microprocessor based hardware and software for motion
control of pneumatic drives. A British Standards based
test-facility has allowed control strategies to be evaluated
with reference to standard performance criteria.
It is demonstrated in this research study that the dynamic
and static performance characteristics of a pneumatic motion
control system can be dramatically improved by applying
appropriate software based realtime control strategies. This
makes the application of computer controlled pneumatic
servos in manufacturing very attractive with cost
performance ratios which match or better alternative drive
technologies.
The research study has led to commercial products
(marketed by Martonair Ltd), in which realtime control
algorithms implementing these control strategy designs are
executed within a microprocessor based motion controller
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