For the kth fly-wheel

−Aqk + Kpk = Ta (qk − sk) + Ta (qk − sk+1),

(4)

Apk + Kqk = −Ta (pk − rk) − Ta (pk − rk+1);

(5)

and for the motion of translation

Mxk = T (rk+1 − rk), Myk = T (sk+1 − sk);

(6)

while the geometrical relations are

xk+1 − xk = a (pk+1 + pk) + 2lrk+1,