Salut Wismermill
j'y ai un peu réfléchié et pour l'instant je garde mes doigts pour controller
Sinon, j'avais trouvé un doc sur une machine industrielle (qui tresse des ceintures de sécurité) (je peux t'envoyer le PDF si tu me donnes ton adresse en MP): En synthèse un frein sur la bobine est piloté par un controleur de tension:
.... Tension controller is
LE-40MTB-E made by Mitsubishi Company in Japan.
As shown in Fig.5, the computer controls the controller
by making the level of “OP” and “SL” high or low
through two transistors. Two tension transducers (for
single line winding, only one transducer) are installed in
the paths of the lines and send tension signals to tension
Controller. By comparing tensions with the desired value,
the controller regulates the torques of the line tubes and
adjusts the tension using magnetic powder brakes.
During the processes of changing line tube or model,
computer sets “OP” high, “SL” low, and the controller
enters “stall” state whose tension is in a fixed value, so
the lines are prevented from getting out of the winding
head.
When “OP” is low and “SL” is high, the control starts
to control the line tension in PID regulation manner. To
realize fast following the objective tension and desired
steady state accuracy, two groups of PID parameters are
used. When the tension controller is just started, big
proportion (Kp) and small integration time (Ti) values
are used, and the tension increases as quickly as possible.
When tension reaches an appropriate value, small
proportion (Kp) and big integration time (Ti) values are
used, then line tension varies slowly and maintains
stably.
To make the tension value from the tension transducer
accord with real tension, the system of the tension
controller and the transducer should be calibrated before
proceeding.
