Research On Signal System And Signal Processing Of Friction Hoists

Friction hoists, kernel component of mining engineering, are complicatedhydromechatronics heavy equipments.Including the basic theory and circuitsexperiments, this article will detail all details of the signal system and signalprocessing of the friction hoists.The key components of velocity/position system are sensors mounted on therotation spindle end and the depth indicator. By acquiring the frequency informationdelivered by pulse encoders, the speed of hoists can be calculated under the specialalgorithm architecture. Besides the location of hoists tanks will be presented by depthindicator. If the tanks over speed or over position, central control units would get thefaults information delivered by signal system and then identify the faults types.According the faults types, CPU commands the corresponding components to work.All of can be the guarantee of safety of the hoists.The reason square wave pulses can’t keep a high fidelity is sensors working in acomplicated electromagnetic environment. To conquer that, a new efficient circuitssystem be designed to transmit the pulses. That is the quite original work of thisarticle.Pulses signal can be switched into voltage by using a Frequency—VoltageConverter (FVC), the frequency of input and the voltage of output will demonstrate alinear positive correlation. In normal case, because of location of sensors, pulsesgenerated by encoders have different frequency. Thus, the output voltage of FVC existdifference. To fit for the subsequent processing, the voltage values need to adjust tomake it equal under a normal state. The voltage can’t keep equal when the hoist wiressliding or depth indicator broking, then the fault messages of system can be acquiredfrom the state of unequal. Next, the differences of different voltages will be sent in thecomparators and compared with the benchmark then output voltage signals mappingwith all kinds fault types. The fault indicator will get voltage signals delivered by anadder and will fall into different threshold ranges according to the signal values. In addition, the same fault message be posted to the CPU, due to the vibration and shockand the plastic deformation, hoist can’t immediately take safety measures. There is adelay in the program, if the fault signal duration would exceed the set time, CPU willsend safety instruction to system to protect. Besides, by adjusting the benchmark ofcomparator, the sensitivity of the faults can be regulated.