A mathematical model of chimpanzees: nut-cracking behavior;A study on the friction torque variation of a ball screw at motion direction change-relationship among friction torque variation of a ball screw at motion direction change of contouring error;Accuracy of kinematic planetary roller-and-screw gear with threaded nut;Accuracy of kinematic planetary roller-and-screw gear;Accuracy of Load-Bearing Planetary Roller-and-Screw Gear with Nut Without Thread……