Tuning the Gemini in Position Mode - Intro
- Jack Degrano
- Eric Rojas
Motion Planner 4.3.0 adds a Servo Tuner for the Gemini series of servo drives (GV6K and GV6). The tuning process is not much different from the process outlined in the applicable drive installation guide, but the software will reveal an easy to use response graph that previously required an oscilloscope. The below procedure outlines how to tune a Gemini Series servo drive with the Servo Tuner software.
IMPORTANT: You must configure the drive for the motor in the application and you must set LJRAT to an appropriate value for the application before beginning the tuning process.
The Servo Tuner is designed to simplify the Gemini tuning process by using sliding controls for setting Response, Damping, and Overshoot.
To start the tuning process, open a "Gemini Servo Tuner" window in Motion Planner (File -> New -> Gemini Servo Tuner).
Next, get a baseline response curve with the default settings. Click Start Motion, the motor should move and a response curve should appear. Change the slider positions and observe the response. A good response is relative to the application requirements, but usually you want a response curve that accelerates quickly, overshoots some, but doesn't oscillate around the end position.
The Response slider adjusts DPBW, which is the Position Loop Bandwidth, essentially the proportional gain of the system. If the response is sluggish then increase this value. If the response overshoots or oscillates then decrease this value.
The Damping slider adjusts SGPRAT, which is the Position Loop Damping Factor. If the response is sluggish, then decrease the damping. If the response oscillates or overshoots, then increase the damping.
The Overshoot adjusts SGVF, which is the velocity feed-forward gain. If the response doesn't accelerate very fast then increase this value. If the response is unstable then decrease this value.
Please note that MotionPlanner 4.3.2 has been updated including the Gemini Servo Tuner: