Application note Advanced servo loop tuning with Optio

Minimum settling time for high-rate indexing The advanced tools integrated in the Optio software (since version x.x) for tuning operations of speed and position control loops allow to achieve high performance in terms of bandwidth, response time and stability. This document describes the servo loops tuning process based on these advanced tools. An application example is also given.

Minimum settling time for high-rate indexing OINFRANOR 1 - BASIC TUNING PROCESS The basic tuning process is described below: Starting the “Auto-tuning” function allows the critical parameters for the axis servo loop tuning to be identified: inertia, friction, rigidity, presence of mechanical resonances. Mechanical resonances are identified and displayed in the Fourier transform (FFT) calculated from the open loop response of the axis (torque mode). If critical resonance frequencies for the closed loop have been identified, the speed regulator notch filters can be used to reduce their influence....

Minimum settling time for high-rate indexing OINFRANOR Prerequisite: -Motor setup is over -Shaft or carriage movement is free Auto-tuning configuration Start Auto-tuning If mechanical resonances, set notch filters according to FFT result. Start with higher resonance frequencies Limit current to low value (5 to 10%) Increase Bandwidth level ^—Motor stability (noise & oscillation free) - at standstill Adjust Tuning level Motor stability"'"-^ (noise & oscillation free) Small displacement (incremental) Profile velocity / Profile position Motor stability In movement Release current limit (100%) 4...

Minimum settling time for high-rate indexing OINFRANOR Controller gain Current command notches { ) Current command low pass Tuning level Speed measurement filter Prerequisite: -Motor setup is over -Shaft or carriage movement is free Auto-tuning configuration Start Auto-tuning If mechanical resonances, set notch filters according to FFT result Limit current to low value (5 to 10%) and enable drive Increase Bandwidth level (Tuning adjustment window) -'-'''Motor stability (noise & oscillation free) at standstill Set current command fillers and speed measurement filter (Advanced tuning window) Bandwidth...

Minimum settling time for high-rate indexing OINFRANOR 3 - APPLICATION EXAMPLE WITH MECHANICAL RESONANCE The coupler reference is HUCO 554 the rigidity coefficient is 38000 Nm/rd -The FP1111 servo motor is equipped with SRS50 Hiperface encoder -The motor shaft and the load are coupled by a high rigidity coupling device -The load inertia / motor inertia ratio is 4. The frequency of the mechanical resonance between motor inertia and load inertia is 664Hz. The stiffness factor (75%) indicates the motor-load mechanical coupling elasticity. For a rigid motor-load mechanical coupling, the stiffness...

Minimum settling time for high-rate indexing OINFRANOR 3.3 - SERVO LOOP RESPONSE WITH BANDWIDTH LEVEL AND TUNING LEVEL ADJUSTMENT The bandwidth level and the tuning level can then be increased progressively in the Auto-tuning window to improve the dynamic performances. The bandwidth limit value and the tuning level limit value depends on the load specifications: mechanical coupling elasticity, backlashes, and frictions. Bandwidth level Tuning level When setting a notch filter with the center frequency equal to the resonance frequency value (664Hz), the bandwidth level and the tuning level can...

Minimum settling time for high-rate indexing Using the advanced tools integrated in the Optio software for tuning operations of speed and position control loops allow to achieve high performance in terms of bandwidth, response time and stability. In summary, the general tuning process involves two steps: -First, identify the open-loop axis parameters using the "Auto-tuning" function. -Then, find the most suitable setting for the axis application in the "Tuning adjustment" window simply by using "Bandwidth level" and "Tuning level" sliders. The use of notch filters allows significant performance...