1) optimization principle of scale planning: when the design requirements meet the requirements of a certain working space, the minimum arm size can be selected through scale optimization, which will help to improve the rigidity of the welding operator and further reduce the inertia of the movement.

2) the principle of minimum motion inertia is inevitable to produce impact and vibration due to the fact that there are many moving parts of the operator and the motion state often changes. The principle of minimum motion inertia can increase the movement stability of the operator and improve the mechanical characteristics of the operation maneuver. Therefore, in the design, we should pay attention to reduce the mass of the moving parts as much as possible on the premise of meeting the strength and rigidity, and pay attention to the configuration of the mass center of the moving parts to the rotating shaft.

3) the selection principle of high-strength materials: since the manipulator works as a load successively from the wrist, small arm, big arm to the base, it is necessary to select high-strength materials to reduce the quality of parts.

4) the principle of rigidity design in the design of manipulator, the rigidity is more important than the strength. In order to maximize the rigidity, it is necessary to properly select the section shape and size of the member, improve the support rigidity and contact rigidity, reasonably arrange the force and moment acting on the arm, and minimize the bending deformation of the member.

5) principle of technology robot operator is a high-precision, high integration automatic mechanical system. Good processing and assembly technology is one of the important principles to be reflected in the design. Only reasonable structure design without good technology will inevitably lead to the reduction of the performance of the operator and the improvement of the cost.

6) reliability principle: because of the complexity of mechanism and many links, the reliability of robot manipulator is particularly important. Generally speaking, the reliability of components should be higher than that of components, while the reliability of components should be higher than that of the whole machine. The reliability of parts or structures can be designed by probability design method, and the reliability of operating machine system can also be evaluated by system reliability synthesis method.