D() (RA)》h -v"Bv h=r+As'-r-As Number of constraint equations 5=2 g=(9,于4，=g,)月 a=aa=o.r o x Degrees of freedom 5=4 Parameters of the constraint i,,s=(69,s=k”,y,y    j i P i P i P i Q j Q j Q j i, j,s  x y , s  x y ,v ,v T T s  2 Degrees of freedom   4 Number of constraint equations   T T i i i q  r Parameters of the constraint   T T j j  j q  r     T T T T T T i j i i j  j q  q q  r r Bj y  x  O j x y j   Cj j r  Q Q j r Q j s P i s i x  i y  Ci Bi ir  P P ir h  i v  j v     0                   i ij j i i t i j t i j t i j v B v RAv h T T ( , ) 2 ( , ) ( , ) 1    P i i i Q j j j h  r  A s  r  A s