The invention discloses a temperature self-adaptive PI control method for flowing glue in a multi-section pipeline. The method comprises the following steps: step 1, identifying a
system and setting initial parameters; predicting
temperature drop of the steel
pipe section; calculating the axial temperature distribution of the glue flowing through the steel
pipe section by using a Schhoff
temperature drop calculation formula to obtain the
inlet temperature of the glue to the glue conveying
pipe; establishing a
heat balance model of the glue conveying pipe; analyzing the
heat transfer characteristic of the glue conveying pipe, and establishing a
dynamic balance equation including
heating power, fluid heat
convection and environmental heat dissipation based on a
steady state condition and infinitesimal dynamic
heat balance of unit length; feedforward compensation is controlled; on the basis of the
heat balance model of the glue conveying pipe, according to a set target temperature,
heating power needed for maintaining the temperature is calculated, and the
heating power is converted into a duty ratio for feed-forward compensation; deducing a
time constant Tdynamic; deriving a function relationship between a
time constant T and quantitative flow in the first-order
inertia plus pure
lag model of the glue conveying pipe; adjusting a self-adaptive PI parameter; and the quantitative flow of glue is monitored in real time, the
time constant T is updated, the proportional
gain and the integral
gain of the PI controller are dynamically adjusted in combination with a
Lambda setting
algorithm, and self-
adaptive control is achieved. Through mechanism modeling, feed-forward compensation and self-adaptive adjustment, the dispensing precision and the
system efficiency are remarkably improved, and the method is suitable for industrial application under the condition that the flow speed is frequently changed.