Just one pinion drives the axis (the "grasp") when the next pinion is "preloaded" to get rid of the backlash (the "slave"). The preload is developed electronically using a special motor controller; these methods can even be arrange to generate with each other throughout cycle moments when backlash isn't crucial. https://gearboxcvt86429.eedblog.com/32769244/a-simple-key-for-gearbox-cvt-unveiled