Setting up Compax3 C3I12T11226 192-120113 N08 C3I12T11 - December 2010Current jerk response with the activated saturation characteristic lineThe parameterization of the characteristic line is made in the MotorManager. In order to accept the changes in the MotorManager in the project, theentire configuration must be confirmed. In order to make the changes from the MotorManager effective in the device, theconfiguration download must be executed.Control measures for drives involving frictionIn this chapter you can read about:Deadband following error ............................................................................................... 226Friction compensation.................................................................................................... 227Some drives, which involve much friction due to their guiding system, may showpermanent oscillation at standstill. The transition between static friction (standstill)and kinetic friction (very low speed) is very steep. The controller can not longerfollow the friction characteristic line at this position. The I-term integrates until thecontrol variable pulls free the drive and the drive moves too far. This procedure isrepeated in the opposite direction and a control oscillation occurs (so-called limitcycle). In order to eliminate this control oscillation, the following control functionswere implemented: Deadband following error (Obj. 2200.20) Filter following error (Obj. 2200.24) Friction compensation (Obj. 2200.20)Deadband following errorDeadband/filter following error in the position loopVvKPxK-T1680.6 Position Tracking error2010.1 Velocity feed-forward2200.20 Deadband –Tracking Error2200.24 Filter - Tracking Error680.5 Actual PositionThe deadband does no longer supply a velocity setpoint value (zero) for thesubordinate velocity loop at small following error. The integrator of the velocity loopstops integrating and the system comes to a standstill.In order to prevent that the velocity loop is excited by the noise on the followingerror, the following error should be filtered before the deadband, which will lead,however, to delays in the position loop. The deadband to be set depends on thefriction behavior (amplitude of the limit cycle) and on the noise on the followingerror (the noise must remain within the deadband).Note:
