When it comes to high performance motion control and nanopositioning equipment, test and metrology data matter, as much as the methods used to acquire the data. PI engineers have been working for years on better ways to measure the figures such as dynamic performance, precision, resolution, repeatability but also geometric accuracy of all kinds of micropositioning and nanopositioning devices, from single axis motorized actuators to complex multi-axis parallel kinematic motion system.
When each individual measurement and qualification step is seen as an instrument for quality assurance, only motion systems and nanopositioning components within the guaranteed specifications will reach the customer.
Depending on the type of motion control component of positioning system, different criteria apply and for highly dynamic applications, rise time, settling time, resonant frequency and body plots may be important, while for static applications stiffness, long term stability, and maximum load and position hold capability without power can be more meaningful.
In either case, the accuracy of the measuring equipment should be significantly better than the component that needs to be tested, in terms of stability, resolution, linearity, etc.