Method for automatically moving on the ground a tool mounted at the end of an articulated arm

Abstract

The invention concerns a method for automatically moving on the ground a tool mounted at the end of an articulated arm. It consists in bringing the tool ( 7, 17, 27 ) onto a first point of the surface and in calculating the co-ordinates of said point; in bringing the tool onto a second point enabling to set a first axis of co-ordinates of the working plan and to determine the furthermost point to be reached on said axis; in bringing the tool onto a third point close to the second co-ordinate axis and enabling to define the position of the frame of reference of the working plan, then in a fourth point delimiting the zone plane inside which the work will be performed and in defining a working plan for the tool capable of being superimposed with the working surface so as to enable it to cover, by discontinuous or continuous movements, the entire working surface.

1 . A method for automatically moving over an area of ground, a tool that is mounted at the end of an articulated arm, characterized in that it consists in defining and calculating a surface known as the working surface from several successive touchings of the tool onto the ground, then in moving the tool ( 7 ,  17 ,  27 ) over the working surface.  
     
     
         2 . The method as claimed in  claim 1 , characterized in that it consists, after defining the working surface, in defining a working pattern for the tool ( 7 ,  17 ,  27 ) that can be superposed with the working surface so as to allow it, through discontinuous or continuous displacements, to cover the entire working surface.  
     
     
         3 . The method as claimed in  claim 2 , characterized in that it consists in bringing the tool ( 7 ,  17 ,  27 ) onto a first point of the surface and in calculating the coordinates of this point which is considered to be the point of origin of the working pattern, in bringing the tool to a second point to orient a first axis of coordinates of the working pattern and to determine the furthest point to be reached along this axis, in bringing the tool to a third point near the second axis of coordinates to define the position of the frame of reference of the working pattern, then to a fourth point delimiting the region of the plane within which the work will be carried out.  
     
     
         4 . The method as claimed in one of claims  2  and  3 , characterized in that it consists in defining a working pattern in which the points reached later by the tool ( 7 ,  17 ,  27 ) are arranged in two perpendicular directions in a sequence such that a step characteristic of the shape of the head of the tool in one direction is followed by a step characteristic of the size of the head of the tool in said direction.  
     
     
         5 . The method as claimed in one of  claims 1  to  4 , characterized in that it consists in controlling the various movements and displacements of the tool using a computer ( 10 ).  
     
     
         6 . The method as claimed in  claim 5 , characterized in that it consists in supplying the computer ( 10 ) with the coordinates of the four points, from which the computer defines a process of displacement of the tool over the entire working surface and controls the members which displace it.  
     
     
         7 . The method as claimed in one of claims  5  and  6 , characterized in that during the work on a surface, the computer ( 10 ) stores in memory the various points reached by the tool, and any points of the surface which might not have been reached, so as to work on them later.  
     
     
         8 . A device for automatically moving over an area of ground, a tool mounted at the end of an articulated arm, for implementing the method as claimed in one of  claims 1  to  7 , characterized in that it comprises a carrier vehicle ( 2 ), on the chassis ( 3 ) of which a turret ( 5 ) is mounted to pivot about a vertical axis (A 1 ), this turret being equipped with an arm ( 6 ) consisting of several elements ( 6   a ,  6   b ,  6   c ) articulated about horizontal axes (A 2 , A 3 , A 4 ) and at the end of which a tool ( 7 ,  17 ,  27 ) is mounted, the turret ( 5 ) comprising an angular sensor (C 1 ) determining the angle it makes with the chassis and each element ( 6   a ,  6   b ,  6   c ) of the arm comprising an angular sensor (C 2 , C 3 , C 4 ) supplying its inclination with respect to the horizontal.  
     
     
         9 . The device as claimed in  claim 8 , characterized in that it comprises a computer ( 10 ) equipped with a program for controlling the displacement of the tool ( 7 ,  17 ,  27 ) to cover the surface that is to be made safe, this computer ( 10 ) receiving the values supplied by the various angular sensors (C 1 , C 2 , C 3 , C 4 ) and delivering at output electrical signals that control electrical directional control valves (E 1 , E 2 , E 3 , E 4 ) hydraulically powering the motor ( 12 ) that turns the turret ( 5 ) and the various rams ( 13 ,  14 ,  15 ) that actuate the elements of the arm ( 6   a ,  6   b ,  6   c ) until the angular values are equal to the calculated values.