The Design And Dynamics Analysis Of Fire-fighting Monitor Based On Parallel Mechanism

As an important tool for remote fire fighting, fire-fighting monitor has been widely usedin large-scale fire control works. However, most of the current fire-fighting monitors adoptseries form to connect bend pipes together, and use the turbine and worm mechanism tochange the spray direction of nozzle. This structure will cause a loss of water pressure in thepipeline and lower firing range, and impact directly on the fire-fighting capability. Parallelmechanisms are being extensively studied by experts and scholars at home and abroad for itshigh stiffness, high load carrying capacity and high precision etc. Based on this background,this paper introduces the parallel mechanism to apply in the fire-fighting monitor systems, inorder to solve the problem of decreased fire-fighting capability of traditional fire-fightingmonitor due to the deficiency of its structure.Firstly, the research status of the parallel mechanism and fire-fighting monitor weredescribed, the problems of the traditional fire-fighting monitor were analyzed, and applyingthe parallel mechanism into the fire-fighting monitor systems was presented. Secondly,according to the needs of movement of the fire-fighting monitor in fire control works, a2-dofdecoupled spherical parallel mechanism with3limbs was proposed on the basis of a2-dofdecoupled spherical parallel mechanism, and its constraints were comprehensively analyzed.This parallel mechanism not only has the characteristics of the movement decoupled, but alsohas higher stiffness and force balance than the original configuration. Thirdly, theintermediate angle of each branched chain was solved on the basis of the kinematics;furthermore, the velocity of each link was obtained including angular velocity, CM velocityand CM angular velocity. The relationship of the basic dimensions of designing the parallelmechanism was given according to the given work space and the motion characteristics.According to the standard size of nozzle, the basic dimensions of the parallel mechanism weredesign. Finally, the dynamics modeling of the parallel mechanism was achieved by using themethod of Kane, and the simulation of kinematics and dynamics of the parallel fire-fightingmonitor has been performed by using ADAMS software.