The Control And Detection System's Design And Research Of Frictional Testing Machine

Friction material is one of the most important parts in the car's brake system, it effects the car's maneuverability, reliability and comfortability directly. Friction material also effects the car's safety. Inertia dynamometer test is typical testing method in the friction and wear test of friction material. Inertia dynamometer test is the most authoritative test in evaluating thefriction behavior of brake linings since the real braking process can be simulated on it. In order to simulate this process, Inertia dynamometer is often designed as an integrated system involving central measuring and control system, mechanical system, hydraulic and pneumatic system plus cooling and cleaning system, since too many test items are involved while there is no uniform test standard. However, domestic inertia dynamometer as a whole stands in a low control level, which depresses the authenticity of brake performance evaluation. On the meantime, imported machines are extremely expensive, the price of which are several times as expensive. It is urgent to develop high performance inertia dynamometer with independent property right.In this paper, a practical inertia dynamometer measurement and control system is developed, aiming at making up the weak point of domestic control system. The overall system uses industrial computer(SHUOHUA IPC610)as upper computer to control overall system'signal process. The lower computer uses programmable con(SIMATIC S7-200)to progress control system and actuator switching value's control. A full digital DC speeder controller(SIMATIC 6RA70 ) is employed as the center of speed-current dual loop speed control system. Adoptting radio emission take(frequency modulation electropult MEC002, frequency modulation reception module TDA7088T) to measure the temperature of the rotating brake drum. Adoptting high frequency proximitiy switch proceed breaking length'smeasure and feedback. Hydraulic servo control subsystem gives a best solution for tube pressure control as well as constant torque control. This measurement and control system gives an optimistic performance when employed in JF122 frictional testingmachine.In the wholl friction testing machine' date control aspect,the most concernning part is the realise instance of contant moment and contant rotation rate in the friction experiment. Hydraulic servo control subsystem is the primary contiol part of contant moment and contant rotation rate. I get the wholl electro-hydraulic servomechanism's mathematics of control model through the medium of analyses hydraulic servo control subsystem. The thereof steady-state error expression is: Through the medium of versus thereof parametric in reason predigestion,we get the thereof close expression fairing is:Through the expression,I analyses the impacting realize constant setting value's major factor is command signal amplitude size and outer loading focr diturb.In order to argue precision of analysis,I adopt a comparison test parting versus both side factor versus constant realize to know clearly experimental analysis .The experimental data argue my versus which impact system stability's mostly two-sided analyses.In the last,in order to let experimental data with curvilinear mode be symptomatic of came,I use vb6.0 proceduce a proper motion filing software to transfer experimental data to curve.