A single pinion drives the axis (the "master") when the second pinion is "preloaded" to remove the backlash (the "slave"). The preload is produced electronically by using a Particular motor controller; these techniques can also be build to generate alongside one another throughout cycle times when backlash is not important. https://gearboxcvt19753.blogthisbiz.com/39328132/rumored-buzz-on-gearbox-cvt