prd(i))=hTh+hTh=2hh=0 h=ro-r ro=r+A so r=r+As i=9-9=i+RA,0,=+B,s0 =+RAs0,=产+B,s0, Time derivative of the velocity constraint equation leads to rd(i.))=2hTh+2hh h=9-”9=书+R4,s0,+RA,s90=-A,9+Bs9, =i+RAs+RAs =-As+Bs 6n-w2al质}r-28看 +2hih-2hTA,syp+2h'As2=Φ，awi-yaD=0 y=-2hh+2h(As-As2)P i Q j h r r    2 0 ( , ) T T T Φ  h h  h h  h h      rd i j Φ h h h h  T  T  ( , )  2  2 rd i j P i Q j h  r  r Q j j j Q j r  r  A s P i i i P ir  r  A s j Q j j j j Q j j j Q r j  r  RA s   r  B s  i P i i i i P i i i P r i  r  RA s   r  B s  Time derivative of the velocity constraint equation leads to P i Q j h r r    j Q j j j Q j j j j Q j j j Q j j j Q j       r  r  RA s  RA s  r  A s  B s 2 i P i i i P i i i i P i i i P i i i P i       r  r  RA s  RA s  r  A s  B s 2     T T 2 T 2 ( , ) T T T T 2 2 2 2 2 2 2 i P j i i Q j j i P i i i j Q j j j rd i j              h h h A s h A s r h h B s r Φ h h B s                        0 ( , ) ( , )    rd i j rd i j Φ q  q    ( , ) T T 2 2 2 2 i P j i i Q j j rd i j        h h  h A s  A s