Determining the actual velocity value (Velocity Observer)
 | Reference values of the Velocity Observer: S-0-0040; S-0-0109; S-0-0111; P-0-0070; P-0-0071; P-0-0073; P-0-0074; P-0-0126; P-0-0127 P-0-0128 |
|
An Observer is a system for representing parameters that are difficult to measure, based on a model and known input and measured variables. For frequencies above around 300 Hz the noise associated with the velocity signal calculated from the feedback becomes problematic. The Velocity Observer of the AX5000 is used to solve this problem. It estimates the acceleration from the measured current and from this the speed signal (through numerical integration). This speed signal is smoother and less susceptible to mechanical resonances. When the Velocity Observer is used, up to the set bandwidth the velocity controller takes into account the speed signal calculated from the feedback, at higher frequencies it takes into account the speed signal estimated from the torque-forming current. The purpose of the Velocity Observer is to provide the velocity controller with a speed signal without resonance-induced oscillations over a wide frequency range. It acts similar to a low-pass filter, but without the disadvantage of a phase shift. The result of the actual velocity value determination with the aid of the Velocity Observer is mapped in parameter S-0-0040. |
| Velocity Observer settings and internal filters! Further information about Velocity Observer settings and a detailed description of the procedure can be found below in this section. |
Functionality from firmware v2.10 | |
| From firmware v2.10, in addition to a third-order observer ("Basic mode"), a fifth-order observer ("Advanced mode") is available for special applications. In Basic mode the position signal calculated from the velocity signal is attenuated with 20 dB / decade above the bandwidth. In Advanced mode attenuation takes place with Both versions, basic and advanced, operate with the cycle of the velocity controller |
