6 research outputs found
Linear identification of a servo-pneumatic system
The identification of a nonlinear system is quite challenging for engineers. This paper presents the automatic identification of a servo-pneumatic cylinder based on a framework implemented in MATLAB. The introduced application shortens the process length of identification and gives areference model, important for controlling
Volume 3 – Conference
We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group 8: Pneumatics
Group 9 | 11: Mobile applications
Group 10: Special domains
Group 12: Novel system architectures
Group 13 | 15: Actuators & sensors
Group 14: Safety & reliabilit
Design and control of components-based integrated servo pneumatic drives
On-off traditional pneumatic drives are most widely used in industry offering
low-cost, simple but flexible mechanical operation and relatively high power to
weight ratio. For a period of decade from mid 1980's to 1990's, some initiatives
were made to develop servo pneumatic drives for most sophisticated
applications, employing purpose-designed control valves for pneumatic drives
and low friction cylinders. However, it is found that the high cost and complex
installation have discouraged the manufacturer from applying servo pneumatic
drives to industrial usage, making them less favourable in comparison to their
electric counterpart. This research aims to develop low-cost servo pneumatic
drives which are capable of point-to-point positioning tasks, suitable for
applications requiring intermediate performance characteristics. In achieving
this objective, a strategy that involves the use of traditional on-off valve, simple
control algorithm and distributed field-bus control networks has been adopted,
namely, the design and control of Components-based Integrated Pneumatic
Drives (CIPDs).
Firstly, a new pneumatic actuator servo motion control strategy has been
developed. With the new motion control strategy, the processes of positioning a
payload can be achieved by opening the control valve only once. Hence, lowspeed
on-off pneumatic control valves can be employed in keeping the cost low,
a key attraction for employing pneumatic drives. The new servo motion control
strategy also provides a way of controlling the load motion speed mechanically.
Meanwhile, a new PD-based three-state closed-loop control algorithm also has
been developed for the new control scheme. This control algorithm provides a
way of adapting traditional PID (Proportional Integral Derivative) control
theories for regulating pneumatic drives. Moreover, a deceleration control
strategy has been developed so that both high-speed and accurate positioning
control can be realised with low cost pneumatic drives. Secondly, the effects of system parameters on the transient response are studied. In assisting the analysis, a second order model is developed to encapsulate the velocity response characteristics of pneumatic drives to a step input signal. Stability
analyses for both open loop and closed-loop control have also been carried out
for the CIPDs with the newly developed motion control strategy. Thirdly, a
distributed control strategy employing Lon Works has been devised and
implemented, offering desirable attributes, high re-configurability, low cost and
easy in installation and maintenance, etc to keep with the traditional strength for
using pneumatic drives. By applying this technology, the CIPDs become
standard components in "real" and "virtual" design environments. A remote
service strategy for CIPDs using TCP/IP communication protocol has also been
developed.
Subsequently a range of experimental verifications has been carried out in the
research. The experimental study of high-speed motion control indicates that the
deceleration control strategy developed in the research can be an effective
method in improving the behaviour of high speed CIPDs. The verification of
open loop system behaviour of CIPDs shows that the model derived is largely
indicative of the likely behaviour for the system considered, and the steady state
velocity can be estimated using the Velocity Gain Kv. The evaluation made on a
pneumatically driven pick-and-place machine has also confirmed that the
system setup, including wiring, tuning, and system reconfiguration can be
achieved in relative ease. This pilot study reveals the potential for employing
CIPDs in building highly flexible cost effective manufacturing machines. It can
thus be concluded that this research has developed successfully a new
dimension and knowledge in both theoretical and practical terms in building
low-cost servo pneumatic drives, which are capable of point-to-point
positioning through employing traditional on-off pneumatic valves and
actuators and through their integration with distributed control technology
(LonWorks) by adopting a component-based design paradigm
Development of a 3-DOF motion simulation platform
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The successful development of a three degree of freedom motion simulation platform,
capable of simulating a vessel’s flight deck at sea, is presented. The motion simulation
platform was developed to practically simulate and test an unmanned aerial vehicle’s
capability of landing on a moving vessel, before practically being demonstrated on an
actual vessel. All aspects of the motion simulation platform’s development are considered,
from the conceptual design to its practical implementation.
The mechanical design and construction of a pneumatic motion simulation platform, as
well as the electronics and software to enable the operation of this motion simulation
platform, are presented. Mathematical models of the pneumatic process and platform
orientation are developed. A controller architecture capable of regulating the pneumatic
process, resulted in the successful control of the motion simulation platform.
Practical motion simulation results of one of the South African Navy Patrol Corvettes,
demonstrate the motion simulation platform’s success. The successful development of the
motion simulation platform can largely be attributed to extensive research, planning and
evaluation of the different development phases.AFRIKAANSE OPSOMMING: In hierdie studie word die suksesvolle ontwikkeling van ’n drie-grade-van-vryheid
bewegingsimulasieplatform, wat in staat is daartoe om ’n skip se vliegdek ter see te
simuleer, aangebied. Die bewegingsimulasieplatform is ontwikkel om ’n onbemande
lugvaartuig se vermoë om op ’n bewegende skip te land, te simuleer en te toets, voor dit op
’n werklike skip gedemonstreer word. Alle aspekte van die ontwikkeling van die
bewegingsimulasieplatform word in ag geneem – van die konsepontwerp tot die praktiese
implementering daarvan.
Die meganiese ontwerp en konstruksie van ’n pneumatiese bewegingsimulasieplatform
word bespreek, sowel as die elektronika en programmatuur wat die werking van hierdie
bewegingsimulasieplatform bemoontlik. Wiskundige modelle van die pneumatiese proses
en platformoriëntering word ontwikkel. ’n Beheerderargitektuur wat in staat is daartoe om
die pneumatiese proses te reguleer, lei tot die suksesvolle beheer van die
bewegingsimulasieplatform.
Praktiese resultate van die bewegingsimulering van een van die Suid-Afrikaanse Vloot se
patrolliekorvette wys daarop dat die bewegingsimulasieplatform wel suksesvol is. Die
geslaagde ontwikkeling van die bewegingsimulasieplatform kan grootliks toegeskryf word
aan omvangryke navorsing, beplanning en evaluering van die onderskeie
ontwikkelingsfases
DESIGN, DEVELOPMENT, AND EVALUATION OF A MRI-GUIDED NEUROSURGICAL INTRACRANIAL ROBOT
Brain tumors are among the most feared complications of cancer. Their treatment is challenging because of the lack of good imaging modality and the inability to remove the complete tumor. To overcome this limitation, we propose to develop a Magnetic Resonance Imaging (MRI)-compatible neurosurgical robot. The robot can be operated under continuous MRI, and the Magnetic Resonance (MR) images can be used to supplement physicians' visual capabilities, resulting in precise tumor removal. We have developed two prototypes of the Minimally Invasive Neurosurgical Intracranial Robot (MINIR) using MRI compatible materials and shape memory alloy (SMA) actuators. The major difference between the two robots is that one uses SMA wire actuators and the other uses SMA spring actuators combined with the tendon-sheath mechanism. Due to space limitation inside the robot body and the strong magnetic field in the MRI scanner, most sensors cannot be used inside the robot body. Hence, one possible approach is to rely on image feedback to control the motion of the robot. In this research, as a preliminary approach, we have relied on image feedback from a camera to control the motion of the robot. Since the image tracking algorithm may fail in some situations, we also developed a temperature feedback control scheme which served as a backup controller for the robot. Experimental results demonstrated that both image feedback and temperature feedback can be used reliably to control the joint motion of the robots.
A series of MRI compatibility tests were performed to evaluate the MRI compatibility of the robots and to assess the degradation in image quality. The experimental results demonstrated that the robots are MRI compatible and created no significant image distortion in the MR images during actuation.
The accomplishments presented in this dissertation represent a significant development of using SMA actuators to actuate MRI-compatible robots. It is anticipated that, in the future, continuous MR imaging would be used reliably to control the motion of the robot. It is aspired that the robot design and the control methods of SMA actuators developed in this research can be utilized in practical applications