The function of virtual axis is to separate the master axis and slave axis. It indirectly changes the signal of the slave axis leaving the master axis unaffected.
The upper half of the chart shows a typical ECAM architecture. When there is a deviation in the terminal of the slave axis, the system sends a signal for a phase alignment value to the master axis. After computing the signal through the ECAM relationship, the deviation in the terminal of the slave axis is affected and deleted. The motion path of master axis is also affected and changes.
The lower half of the chart reveals the new system master axis M’. It is the combination of virtual axis and original master axis in an E-Gear relationship (1:1 synchronous). The signal is sent to the virtual axis and compensates the deviation value of the phase alignment. The motion path of the virtual axis is affected but the original master axis is not.