Ci Si -Si Ci i i Rz (ei) = 2. Translation the matrix 1 0 Trz(di) = 0 0 0 0 0 0 1 0 0 0 0 1 of di units along axis zi-1 described by 0 0 0 1 0 0 0 0 1 d 0 0 0 1 3. Translation of homogeneous transform Trx (ai) = ai units along axis xi, with 1 0 0 ai 0 1 0 0 0 0 1 0 0 0 0 1 4. Rotation about xi of angle ai, Rx(a i) = 1 0 0 0 0 7i -Ci 0 ai i 0 a1 r 0 0 0 1 The matrix A1 of Eq. (2.1) is obtained by the product (Paul, 1981), (2.3) (2.4) (2.5) (2.6) ..