In the following, we show to you how to use the hybrid position control at ctrlX DRIVE.
Version used
All the functions and screen shots are based on:
- ctrlX Drive Engineering version 1.13
- Runtime/Firmware version of drive AXS-V-0308N-NN-02
Prerequisites
A connection to the ctrlX DRIVE has been successfully established, the device is correctly wired and 24 V are successfully put on. As well the engineering tool ctrlX DRIVE Engineering has been started.
1. What the function is good for
Using the hybrid actual position value is particularly advantageous if there is only a low degree of stiffness between attachment of external encoder to main mechanics moved.
This function, if compared to completely closing the position loop to just the external encoder, usually allows to increase the position loop P- gain (kV Factor, parameter S-0-0104) to get a more stable regulation loop, as the position loop is mainly closed over the stiffly attached motor encoder, whilst still getting a good accuracy, as bigger position errors are compensated over the external encoder on the load side not that stiffly attached to the main mechanics.
Mind: In the case of slip between motor encoder and external encoder, it is advantageous to additionally activate the measuring wheel mode.
2. Prerequisite for using the hybrid position control
In order to activate the function the so-called productivity package must be present. It should normally already be ordered correctly or, if not ordered, be licensed afterwards by “Import license”.
Fig. 1: Enable Hybrid position control in „Productivity“ package
The “Hybrid position control” function itself then need to be selected and activated by a “Reboot”.
3. Configure parameters
First configure enocder 1&2, then you can activate hybrid position control at a position operation mode e.g. drive internal interpolation.
Fig. 2: Settings Hybrid position control
4. Result and use cases
To demonstrate the effect a MS2N06 motor as encoder 1 and MSK50 motor as encoder 2 were used and the shafts were connected via belt.
Fig. 3: Demo Modell
To see the behavior, S-0-0051, S-0-0053 and S-0-0386 (covered by S-0-0053 in the measurement) are scoped.
Fig. 4: Behavior encoder 1&2
Additionally to compare and see the effect of the hybrid position control, the arithmetic of S-0-0053 – S-0-0386 is built.
P-0-0241 is used to smooth and determine the influence of encoder value 1. The bigger the time constant, the bigger the influence of encoder 1 (see below).
Fig. 5: Result and influence encoder 1 (black with P-0-0241 set to "0ms", orange set to "250ms", green set to "500ms")
