A kinematic
system (100) for compensating the weight of a
mass (10), said kinematic
system (100) comprising a first link (110) arranged, in use, to be integrally constrained to the
mass (10); a second link (120) arranged, in use, to be integrally constrained to a frame (20),, and being rotatably connected to the first link (110) by means of a first
rotational joint (115) having a rotation axis Z1 orthogonal to a plane Π and intersecting the plane Π in a first center of rotation O 1 the
mass generating a
gravitational torque Mg with respect to the first rotation axis Z1; a third link (130) rotatably connected to the second link (120) by means of a second
rotational joint (125) having a second rotation axis Z2 orthogonal to the plane Π and intersecting the plane Π in a second center of rotation O 2; a fourth link (140) rotatably connected to the third link (130) by means of a third
rotational joint (135) having a third rotation axis Z3 orthogonal to the plane Π and intersecting the plane Π in a third center of rotation 0 3, the fourth link (140) being also rotatably connected to the first link (110) by means of a fourth rotational joint (145) having a fourth rotation axis Z4 orthogonal to the plane Π and intersecting the plane Π in a fourth center of rotation O 4. In particular, the segment (I) has length equal to l 2, the segment (II) has length equal to l 3 ≥ l 2 , the segment (III) has length equal to l 4 ≥ l 2 and the segment (IV) has length equal to l 4 ≥ l 2. Furthermore, the segment (V) forms with the segment (VI) an angle equal to v 1, the segment (VII) forms with the segment (VIII) an angle equal to v 2, the segment (IX) forms with the segment (X) an angle equal to v 3 and the segment (XI) forms with the segment (XII) an angle equal to v 4. In particular, the kinematic
system (100) is configured in such a way that if l 1 ≥ l 3 and l 1 ≥ l 4 then l 1 + l 2 ≤ l 3 + l 4, if l 3 ≤ l 1 and l 3 ≥ l 4 then l 3 + l 2 ≤ l 1 + l 4 and if l 4 ≥ l 1 and l 4 ≥ l 3 then l 4 + l 2 ≤l 1 + l 3. Furthermore, at least one elastic group (116, 126, 136, 146) is provided arranged generate an elastic torque M el with respect to the first rotation axis %1 opposite in direction to the
gravitational torque Mg.