| Along with the development of society and advances of science and technology, the paceof Chinese urbanization gradually speeds up, modernization factories and Residentialbuildings are built, and the population is highly concentrated. However, extremely heavylosses will be caused if we fail to fight the fire quickly and accurately once the fire happensbecause the fire risk and danger is much bigger, and the rescue work is much harder thanbefore. In order to improve the efficiency of the available automatic fire-fighting monitor andappeal to the trend of high demands about the location accuracy of the automatic fire-fightingmonitor, based on the kinematics and error analysis of the spherical five-bar mechanism, aspecial kind of spherical five-bar mechanisms known as2-DOF spherical parallel mechanismis used as the swing mechanism of the automatic fire-fighting monitor in this work. It changedthe hanging stick structure of the available fire-fighting monitor to make its volume reduced,center of gravity lowered, stiffness enhanced, and influence of recoil force when spurtingliquid to put out the fire decreased. In this way, the kinematical capability, location accuracyand stability of the general fire-fighting monitor are promoted, the accumulation andamplification of inertia and error are avoided, and it’s much easier for the fire-fightingmonitor to aim at the fire to improve its performance and efficiency. The main contents in thiswork include the following aspects:(1) Kinematics analysis based on screw theory. Build the kinematics model to deduce theexpression of position, velocity and acceleration of2-DOF Spherical parallel five-barmechanism. Get the position coordinates curves variation with time about thex， y， zdirections of reference point R with the numeric simulations, and the validity of themotion model is demonstrated.(2) Analysis the error of2-DOF Spherical parallel five-bar mechanism with matrixmethod For the purpose of studying the impact of dimension error to the end-actuatormechanism of intelligent fire-fighting monitor, obtain the Vector Model of output positionerror w,velocity error w, acceleration error w with consideration about the structuralerrors without randomness, and the derivate equation of mean value Wand standarddeviation2Wof output displacement. The mean value and standard deviation curves ofposition of point R variation with time on the directions of x， y， z are accomplished withthe numeric simulations as well as the3curves of mechanism precision, meanwhile; thevalidity of the error model is demonstrated.(3) Design the intelligent fire-fighting monitor with2-DOF spherical parallel swingmechanism. Two specific design schemes and their three-dimensional models are proposed inthis article based on the kinematics analysis and error analysis. One of them is used to connect to the urban infrastructure or the firefighting hose, and the fire extinguishing agent get outthrough the swing mechanism while the other join the end-actuator mechanism directly.(4) On the basis of the structure design and kinematics analysis above, design theperipheral hardware circuit including fire detection, communication Interface, main controlchips circuit which contains peripheral control circuit, ups, program download circuit, andexternal power detection circuit, and motor drive circuit of the control system. Moreover,flow chart of the control system is also proposed in this work.In this article, theoretical basis for the2-DOF spherical parallel mechanism applicationsis presented, application field of spherical five-bar mechanism is broadened, and an effectivemethod to improve the efficiency and precision of automatic fire-fighting monitor is proposedbased on kinematics and error analysis of spherical five-bar mechanism, and the study of itsuse in the automatic fire-fighting monitor. |
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