Pendulum sway

  1. Define the effective pendulum length (oscillation is to be suppressed at this pendulum length) by configuring the "Configured pendulum length/offset", "Pendulum length from axis" and "Pendulum length from fieldbus in mm" in the "Configuration of effective pendulum length" area. The following figure illustrates the parameters available for this application type. For detailed descriptions of the parameters, refer to chapter Anti-sway control. The effective pendulum length is calculated from the sum of these 3 parameters and corresponds, for example, to the actual length in [m] of the rope of a crane application from the rope fixed point to the end of the rope or, if the load is attached, up to its center of gravity.
    • Configured pendulum length/offset: Specification of a fixed pendulum length or an offset in [m]
    • Pendulum length from axis: Use a pendulum length from a selectable axis, axis group or MOVIKIT® EncoderInterface. As a result, the oscillation suppression is always in relation to the pendulum length. To do so, select the axis for the lifting position and the user units of the lifting position via the displayed setting fields. The "Rope fixed point" must be specified as the position of the lifting axis at the marked point. The "effective direction of lifting" must be configured positively if the lifting position becomes larger when traveling downwards (rope becomes longer). The value for pendulum length from axis is calculated from: ((Lifting position × user unit) - fixed rope point) × Effective direction of lifting.
    • Pendulum length of fieldbus in mm: A value in [mm] can be specified via the fieldbus interface using the process data word "Distance between lifting and traveling vehicle". This means that, for example variable effective pendulum lengths due to changing load centers or lifting position information from external axes are taken into account.

[1]

Configured pendulum length/offset

[2]

Pendulum length from axis

[3]

Fixed rope point

[4]

Pendulum length of the fieldbus in mm

[1]+[2]+[4]

Effective pendulum length

  1. Specify the time window by configuring "Oscillation suppression" in the "Time window" area. The larger the time window, the more time is provided for the correction movement of the oscillation suppression and the dynamics of the correction signal is reduced. The positioning process is therefore extended by the time window. However, the jerk time of the travel axis can be reduced at the same time. A value is suggested for the parameter that you can apply and adjust, if necessary. The "Cycle time of the HighPrio task for limit value calculation" is also displayed in this area. The displayed value is drawn from the "Controller setpoint cycle" parameter of the lower-level member.
  2. Configure a pendulum length filter to filter the signal of the effective pendulum length. If the pendulum length is used by an interpolated axis of the same controller, no pendulum length filter is required (setting "No filtering"). If the pendulum length changes during acceleration or deceleration of the travel axis, the pendulum length filter is required (setting "Dynamic filter") if ...
    • The pendulum length is specified via fieldbus or a MOVIKIT® EncoderInterface
    • The pendulum length is noisy (e.g. due to sensors or encoders)
    • The pendulum length in the 2nd derivative is not continuous (e.g. due to an additive position jump via fieldbus)