Device and method for determining an axis of a rigid body

A device for determining an axis joining origins of first and second reference systems of a rigid body whose relative positions and orientation are not priorly known, the device comprising:

• a first inertial sensor and a second inertial sensor, each provided with a triaxial accelerometer and a triaxial gyroscope, arranged to be constrained to said rigid body and for respectively defining the first and the second reference system;
• a processing unit, connected to the inertial sensors, comprising:
• an acquiring module configured to acquire first data representing angular velocities and second data representing linear accelerations of the rigid body detected by the first and second inertial sensors during a movement of the rigid body itself;
• a first calculating module configured to calculate third data representing angular accelerations of the rigid body as a function of the acquired first data;
• a second calculating module configured to calculate a relative orientation between the first and the second reference system as a function of the first data;
• and
• a third calculating module configured to calculate a vector which joins origins of the first and of the second reference system as a function of said first, second and third data and as a function of the relative orientation calculated between the first and the second reference system, wherein a primary direction of a primary vector is representative of the axis joining the origins of the first and second reference systems;
• a first fixing component fixed to a first end of the rigid body, wherein the first fixing component comprises:
• a fixing system fixed to the first end of the rigid body with one or more pins;
• a cutting guide comprising a cutting tool and maintaining the cutting tool in a constant orientation;
• a regulating device structured to connect the cutting guide to the fixing system and to modify the orientation in the space of the cutting guide with respect to the fixing system;
• wherein the first inertial sensor is mounted in a first position solidly constrained, in terms of orientation, to the cutting guide;
• a second fixing component structured to be fixed to a second end of the rigid body at the second inertial sensor positioned in a second position different from the first position.