Above: piezosystems-jena Digital piezo-controller d-drive
piezosystem jena offers a more effective closed loop control for piezo actuators, including a feed forward system and customized filters. These new features available with our digital controllers differ significantly from conventional electronics available in the market today. The solutions are also completely compatible with older piezo stages, so they can also be immediately used with existing actuators already installed in your setup.
Dynamic applications demand strict requirements from control electronics of piezoelectric actuators. With this in mind, piezosystem jena significantly expanded the capabilities of these digital closed loop systems. A set point feed forward control with improved filter options offers a more targeted positional adjustment for industrial applications. The new optional set point control is based on the proven PID control loop:
- Conventional: only the difference between the set point and the actual measurement value serves as a controlled variable.
- New: bypassing the control loop by applying approx. 80% of the set point voltage as a first estimation
- Advantage: smaller initial control deviation leads to faster positioning
In dynamic applications, piezosystem jena was able to achieve significant progress thanks to this principle. For example, using a sinusoidal test signal the phase shift between set point and actual position value, and thus the time the system is "trailing" behind the set point, could be reduced by a factor or three.Another major improvement of our closed loop systems is the customization of filter parameters. piezosystem jena has changed a number of filter parameters to be variable and thus customizable by the end user.
- Conventional: cut-off frequencies of the filters are set to default values
- New: cut-off frequencies of the filters can be adjusted to the resonance frequency of a particular system.
- Advantage: higher speed and increased control loop bandwidth
Figure:schematic representation of the new control loop. Left: Reaction to a sinusoidal excitation. The piezo lags behind the set point signal due to calculation and filter times. Right: The new signal feed forward reduces the temporal and spatial offset. In a test system (20µm stroke, frequency 20Hz) the spatial offset could be reduced from 1.2µm to 0.4µm.