There are two problems taking troubles to the rapid advancement of water mist fire suppression technology. One is that the extinguishing
abilities of water mist can not be exerted sufficiently. The other is that people can not establish a scientific standard of water
mist fire suppression systems. This paper is tyring to solve the problems.
In this thesis, a fixed high pressure single-phase water mist fire suppression system is investigated by means of theoretical analysis,
simulations and experiments. A water mist fire suppression system driven by water hydraulic piston pump is developed and the
water hydraulic parts are successfully applied in fire-fighting field. A new two-stage atomizing structure is brought forward and a
new two-stage atomizing water mist spray head is developed. Series of water mist extinguishing tests of pool and wood fires are
carried out while the dimensional temperature fields of the fire enclosure are measured. CFD water mist fire simulations are done and
some results are compared with tests. Furthermore, the effects of room dimensions, locations of spray head and spray parameters on
fire extinguishing time are studied. Suggestions are given about how to determine spry intensity of system design.
In this thesis, a principle design of hydraulic systems for simulator test rig is carried out theoretically with electro-hydraulic proportional
control technique. The control method of both the thrust pressure and the thrust speed is investigated, and the synchronization
control of the hydraulic cylinders is also completed. The simulation and experimental results show that the thrust pressure and
thrust speed can be controlled through the integration of pressure and flow control technique, and the synchronization precision of the
thrust system can be controlled within the range of ±3 mm. On the other hand, the earth pressure balance mechanism is analyzed. The
earth pressure can be controlled within the range of set value by controlling the revolving speed of the screw conveyor according to
the real time feedback of the earth pressure in the working chamber, which can realize the earth pressure balance basically, and the
experimental results show that the earth pressure is generally at 20 kPa in the clayey soil. Moreover, the calculation equations of the
total thrust force and the torque of the cutting wheel are obtained, and the relationships between the working parameters of the shield
and the soils are discussed.
Zhejiang University, Hangzhou, China
Autonomous Cleaning Robot is a kind of intelligent mobile robot, which collects dust while running at home. As home service
robot, it differs greatly from industrial robot. Nowadays, industrial robot has been put in use widely in manufacturing, while it’s just
a start for cleaning robot. Self learning and self operation in the unstructured environment is still a difficulty for the cleaning robot,
which is a research focus for artificial intelligence and robotics. Environment perception and modelling, mobile robot’s selflocalization,
self planning, self protection and self service, robot commercialization are involved. And this kind of cleaning robot is
really needed to ease the tedious everyday cleaning burden off the people. This means broad market demand. So the autonomous
cleaning robot has great research value and application prospect.
The aim of the thesis is to settle the above-mentioned problems and construct a real home service robot, which can do cleaning
work continuously and independently, no harm to environment, users and itself. This thesis concentrates on self learning and self
operation in the unstructured environment. It constructs the framework of the robot system, studies on the basic theory and technology.
The primary work includes obstacle detection system based on infrared sensors, mobile robot’s self-localization based on two
incremental encoders, intelligent planning, self protection and self service, and embedded control system for the robot.
As the research object, a 20-ton class HE driven by double-pump is modeled within Simulink and SimMechanics environment of
MATLAB. Based on the study of energy distribution, the schemes of parallel and series hybrid systems are evaluated, according to
their fuel consumption, equipped power of working components and working parameters. The parallel hybrid system with the capacitor
as energy accumulator and the project of energy regeneration with hydraulic motors are explored in detail, combining theoretical
analysis, computer simulation and experimental research. Finally, a scheme with a series of energy saving methods, such as parallel
hybrid, separately driving, electric motor driving swing and the energy regeneration with hydraulic motor, is presented and synthetically
evaluated.
This doctoral thesis comes from the project “Free Piston Engine Hydraulic Reciprocating Pump” supported by the National High
Technology Research and Development Program (“863” Program, the project serial number is 2001 AA423150) and the project
“Study on the Mechanism of Hydraulic Free Piston Internal Combustion Engine” (the project serial number 50075077) supported by
National Science Foundation of china (NSFC).
A hydraulic free piston engine (abbreviated as HFPE) integrates internal combustion engine and a hydraulic pump into one compact
unit. In practical view, there is only one linearly moving part, i.e. the piston assemble in the HFPE. Comparing with crankshaft
internal combustion engine , the piston assemble within HFPE is not restricted by any mechanical linkages, so its motion between
left and right extremes occurs by means of the fuel energy, simultaneously its hydraulic piston directly produce hydraulic energy.
Comparing with the single piston or opposed piston HFPE, the dual piston HFPE (abbreviated as DHFPE) has its own special
features such as the highest power density, so the aim of this thesis is to study the mechanism of DHFPE and its key component.
In this thesis, application of numerical simulation of the unsteady flow and cavitation in hydraulic valve is reported. The unsteady
flow and the cavitation are basic sound sources in hydraulic valves. Thus there is a variety of factors that influence the final noise.
Elementary research was mainly based on the experiments. Present numerical modelling can be a useful tool in studying and understanding
the physical phenomena. To take these phenomena into account, the whole set of the three-dimensional, time dependent
conservation equations defined for mass, momentum and scalar quantities must be solved. Rapid progress in the field of the flow,
cavitation and their noise modelling is closely connected with the solution of actual technical problems. In this thesis the attention is
focused on the numerical modelling of flow in the hydraulic valve, interpretation the flow fields, identification of the noise sources
and applicability of the used CFD code. The thesis is divided into two parts. The possibilities of the CFD code are tested on simple
valve, and the results of simulations are compared with experimental measurement in the first part. The obtained knowledge is applied
on real hydraulic valve in the second part. The modification effect of the throttling area on generated noise is evaluated.
Nevertheless dominant in the development of software systems, object oriented methodology is also becoming more current in
modelling of complex physical systems. The reason does not only lie in the need of the final model form to be performed on the
computer (simulation), but in the fact that software is becoming the compound unit of projecting and performing of such systems.
The aim is to perform the entire software support, including modelling, simulation, projecting and implementation, by means of
consistent methodology. Main advantages of the objectively oriented approach are namely: flexibility, easier maintenance and larger
possibility of reusing the existing models. In such a way, the process of modelling is performed in more natural way, which is innate
to the projecting of a hardware system.
The subject of this work is defining and developing of concepts which constitute the vocabulary used to describe the behavior of
physical systems in general sense, that is, the behavior of fluid-electrical control components and systems in the concrete sense, all
based on object oriented methodology at conceptual and implementation level.
Fundamental issue to be determining any given methodology is the language which is to be used for system description. Language
selection determines the terms which can be included in the model (vocabulary), together with the way of forming models
(grammar). Due to large conceptual distance of the original and final model domain, there is not a single language which is expressive
enough to describe the system in all modelling phases. Therefore, there comes the need to transform concepts from one abstraction
level to another.
Throughout the paper, behavior modelling of the dynamic system is viewed from the perspective of energetic flows in the system.
In other words, energetic domain is accepted as original domain. For this reason, energetic mechanisms of bond graph methodology
are used for the forming of conceptual model. This methodology, which in its core unites energetically based ontology and the
ontology of concentrated parameters, fundamentally corresponds the structural part of object approach metamodel.
As the ultimate one, domain defined by Unified Modelling Language (UML) metamodel, has been accepted. UML becomes an
industrial standard in modelling a software system. Models of this format are easily translated into the executive code, both independently
or by means of any general use generator code. Beside the possibility of model exchange between different domains, there
is also the possibility of unifying different models of one complex system with an integrated software.
The application of developed concepts (classes) is to be illustrated by means of behavior modelling and simulation of hydraulic
cylinder.