关节角

${\theta }_1$

${\theta }_2$

${\theta }_3$

${\theta }_4$

${\theta }_6$

角度

$\frac{\pi }{2}$

$\frac{\pi }{4}$

$\frac{\pi }{3}$

$\frac{\pi }{2}$

$\frac{\pi }{6}$

$\frac{2\pi }{3}$