How many degrees of freedom does the mechanical arm have?

A turntable, a shoulder joint, an elbow joint, a wrist joint and four * * *.

The turntable is 360, the shoulder joint is in the range of 65438+080, and the rotation range of elbow joint and wrist joint is in the range of 360, without interference.

F = 3n-(2pl+Ph)n: number of active components, pl: number of low secondary constraints Ph: number of high secondary constraints.

f = 3 * 4-（2 * 4+0）= 4