Lower pairs(低副)：joints with surface contact Prismatic joint Revolute joint Cylindric joint Spherical joint Helical joint Planar joint Type Pjoint R joint Cjoint S joint Hjoint F joint DOF 2 3
Lower pairs（低副）:joints with surface contact Prismatic joint Revolute joint Cylindric joint Spherical joint Helical joint Planar joint Type P joint R joint C joint S joint H joint F joint DOF 1 1 2 3 1 3
Higher pairs(高副)：joints with point or line contact DOF
Higher pairs（高副）:joints with point or line contact DOF 5 2
Examples of higher pairs Form-closed Force-closed closed by its geometry need external force
Examples of higher pairs Force –closed need external force Form –closed closed by its geometry
Diagram of Kinematic pairs(运动副简图) Prismatic joint Revolute joint Cylindric joint Spherical joint Helical joint Diagram Type Pjoint R joint C joint S joint Hjoint DOF 1 2 3 1
Diagram of Kinematic pairs（运动副简图） Prismatic joint Revolute joint Cylindric joint Spherical joint Helical joint Type P joint R joint C joint S joint H joint DOF 1 1 2 3 1 Diagram
Machine Element(机械零件)：minimum unit during manufacturing This link has several machine elements Binary link
Machine Element（机械零件）: minimum unit during manufacturing Binary link This link has several machine elements