| 主权项 |
1. A system for plotting a mark drawn on a writing medium, comprising:
a tool, chosen from the group consisting of a pencil and an eraser, said tool comprising:
a body for grasping the tool with a hand of a user,a tip adapted to draw the mark to be plotted, said tip being movable by a reactive force exerted on the writing medium when said tip comes to rest on said writing medium, between:
a prominent position anda retracted position in which the tip is pushed inside the body more than in the prominent position,a return continually driving the tip towards its prominent position,first and second, separate, permanent magnets, the first permanent magnet being mechanically linked to the tip so as to be moved translationally or rotationally, in relation to the second permanent magnet, as the tip is moved between its prominent and retracted positions, a device adapted to record successive positions of a point of contact between the tip and the medium in order to form the plot of the drawn mark, and of using a value of a physical quantity that is representative of the pressure exerted on the tip of the tool in order to control or complete said recording, wherein the device includes: a network of magnetometers having N triaxial magnetometers that are mechanically linked to one another without any degree of freedom in order to preserve a known distance between each of said magnetometers, where N is an integer greater than or equal to five, an electronic computer that is programmed in order to:
a) determine, from the measurements from the triaxial magnetometers, the positions of the two permanent magnets and the orientations of the magnetic moments of the two permanent magnets by resolving a predetermined system of equations linking each measurement from a triaxial magnetometer in the network to the positions of the two permanent magnets and to the orientations of the magnetic moments of said two permanent magnets,b) calculate one of the relative position of the first permanent magnet in relation to the position of the second magnet from the positions determined in step a) and the relative orientation of the magnetic moment of the first permanent magnet in relation to the orientation of the magnetic moment of the second permanent magnet from the orientations determined in step a), said calculated relative position or orientation then being used by the device as a value of the physical quantity that is representative of the pressure exerted on the tip. |
