Definition of the constraint Inertial frame O-e B Body-fixed frame of B C, 9,=,) P 9s=(9 is given Body-fixed frame of B, C,-e; 4=9,)厂 5=y)is given Define vector h=0p=9-=时+9--s” h=r+As-r-As The distance between P and Q is constant:c h.h-c2=0 rd(i.i)=hh-c2=0• Definition of the constraint Bj y  x  O j x  j y  Cj j r  P Q j r Q j s e  Inertial frame O  C j j e  Body-fixed frame of Bj    T T j j  j q  r Q j s   Q T j Q j Q j s  x  y  is given P i s   T T i i i q  r P i s   T P i P i P i s  x  y  is given C i i e  Body-fixed frame of Bi  i x  i y  Ci Bi ir Q h  P ir Define vector h  QP  P i Q j r r     P i i Q j j r s r s         P i i i Q j j j h  r  A s  r  As 0 2 h  h  c     The distance between P and Q is constant：c 0 T 2  h h  c  rd (i, j)  Bj y  x  O j x  j y  Cj j r  P Q j r Q j s P i s i x  i y  Ci Bi ir Q h  P ir