(1) Functional requirements for displacement machinery: Refers to what actions the displacement machinery should be able to achieve, such as translation, lifting or rotation. If it is a translation, is it linear translation or curved translation; if it is a rotary motion, is it continuous rotation or intermittent flipping, etc.;
(2) Requirements for movement speed: It is necessary to clarify whether it is fast or slow, constant speed or variable speed, stepwise speed change or stepless speed change;
(3) Requirements for smoothness and accuracy of transmission: the positioner used for automatic welding requires high accuracy in transmission. At this time, worm transmission and gear transmission can be selected;
(4) Requirements for self-locking, overload protection, vibration absorption, etc.: For general lifting or overturning, and overturning dangerous transmissions, the transmission mechanism must have self-locking capability for safety. There may be multiple transmission modes and their corresponding transmission mechanisms. At this time, it is necessary to comprehensively consider the transmission power between them, the compactness of the size, the transmission efficiency and the manufacturing cost.