One pinion drives the axis (the "grasp") though the next pinion is "preloaded" to remove the backlash (the "slave"). The preload is established electronically that has a Specific motor controller; these techniques can also be arrange to push with each other throughout cycle moments when backlash is not really vital. https://gearbox-cvt31963.blogdosaga.com/32614088/everything-about-gearbox-cvt