Winding apparatus providing steady tension

A winding apparatus providing steady tension, comprising:

• a loading unit having a roller and an actuator, wherein the roller is rotatable and is adapted to support a roll of a sheet and to release the sheet, the roller sends out an angle signal corresponding to a rotation angle of the roller, the actuator connects with the roller and introduces an output torque to the roller, and the actuator outputs a torque signal corresponding to the output torque;
• a winding unit adapted to collect the sheet into a roll form;
• a dancer roller arranged between the loading unit and the winding unit and outputting a shift signal corresponding to a shift quantity of the dancer roller;
• a tension sensing unit arranged between the loading unit and winding unit and outputting a tension signal corresponding to a sensed tensional quantity of the sheet;
• a calculating unit electrically connecting with the roller, the actuator, the dancer roller, and the tension sensing unit to receive the signals and generating a torque command signal;
• and
• a command unit electrically connecting with the actuator, the dancer roller and the calculating unit to receive the torque command signal and producing a control signal by the torque command signal or a velocity signal, wherein the calculating unit has a directional filter, a first differentiator, a second differentiator, a divider, a torque calculator, and a subtracter, the directional filter connects with the dancer roller to obtain and output data of the shift signal in a predetermined direction, the first differentiator connects with the directional filter and differentiates an output of the directional filter to obtain the velocity signal, the second differentiator connects with the roller and differentiates the angle signal to obtain an angular velocity signal, the divider connects with the first and second differentiators to divide the velocity signal by the angular velocity signal, the torque calculator connects with the divider and the tension sensing unit to multiply an output of the divider by the tension signal, and the subtracter connects with the torque calculator and the actuator and subtracts the torque signal from an output of the torque calculator to obtain the torque command signal.