ElmoMC SimplIQ Software Manual - Manual (Page 219)

SimplIQ Software Manual
MAN-SIMSW (Ver. 1.4)
15-1
Chapter 15: The Controller
This chapter, which provides details about the speed and position control algorithms, is
written for the advanced user who wants to tune the
SimplIQ servo drive manually, rather
than using the Composer application. It also explains what processes occur when the
Composer tunes the servo drive. Familiarity with basic digital control theory is mandatory.
Not covered in this chapter is the digital control loop.
The type of controller used depends on the SimplIQ drive motion mode (see Chapter 10: ):
Unit Mode Control Algorithm
1 Open loop.
2 Speed control.
3 Micro-stepper.
4 Position, dual-feedback source. One sensor is used for commutation
and speed control while the other sensor serves for load position
control.
5 Position, single-feedback source.
Table 15-1: Unit Mode Values and Definitions
At the basic level of the speed controller, the control algorithm is the traditional PI
(proportional - integral). At the basic level of the position controller, the control algorithm is
an internal PI speed loop and an external position loop using a simple gain for the
controller, a structure known as a cascaded loop.
As control requirements become more stringent, the algorithms can be extended to include:
ƒ
A high-order filter that operates in series with the PI controller, with the following
blocks:
ƒ Notch filters for notching resonance
ƒ Low-pass filters for attenuating very high-frequency resonance and decreasing
sensor noise
ƒ A lead-lag element, which moderates the tradeoff of margins versus bandwidth
ƒ A continuous scheduling algorithm that modifies the PI algorithm and some of the
advanced filter parameters as a function of the closed loop operating point
An advanced user may tune the various filter blocks, which is a bit more complex than
tuning the PI and simple gain. The gain scheduling can programmed by the Composer
Wizard automatically or manually, using the Advanced Manual Tuning options (explained
in Chapter 4 of the Composer for
SimplIQ Servo Drive User Manual).