Patent ID: 7219561

Claim:
A force detection device comprising: a force receiving member ( 10 ; 100 ), receiving forces to be detected; a supporting member ( 20 ; 300 ), positioned below the force receiving member; a first force transmitting member ( 11 ; T 1 ), having an upper end thereof connected to said force receiving member and a lower end thereof connected via a connecting member ( 215 ), having flexibility, to said supporting member; a second force transmitting member ( 12 ; T 2 ), having an upper end thereof connected to said force receiving member and a lower end thereof connected via a connecting member ( 225 ), having flexibility, to said supporting member; a third force transmitting member ( 13 ; T 3 ), having an upper end thereof connected to said force receiving member and a lower end thereof connected via a connecting member ( 235 ), having flexibility, to said supporting member; a fourth force transmitting member ( 14 ; T 4 ), having an upper end thereof connected to said force receiving member and a lower end thereof connected via a connecting member ( 245 ), having flexibility, to said supporting member; a first sensor ( 21 ; S 1 ) having capacitance elements (C 11 to C 15 ) each of which comprises a fixed electrode (E 11 to E 15 ), fixed to said supporting member, and a displaceable electrode ( 215 ), fixed to a displaceable surface that becomes displaced in accordance to a displacement of a lower part of said first force transmitting member; a second sensor ( 22 ; S 2 ) having capacitance elements (C 21 to C 25 ) each of which comprises a fixed electrode (E 21 to E 25 ), fixed to said supporting member, and a displaceable electrode ( 225 ), fixed to a displaceable surface that becomes displaced in accordance to a displacement of a lower part of said second force transmitting member; a third sensor ( 23 ; S 3 ) having capacitance elements (C 31 to C 35 ) each of which comprises a fixed electrode (E 31 to E 35 ), fixed to said supporting member, and a displaceable electrode ( 235 ), fixed to a displaceable surface that becomes displaced in accordance to a displacement of a lower part of said third force transmitting member; a fourth sensor ( 24 ; S 4 ) having capacitance elements (C 41 to C 45 ) each of which comprises a fixed electrode (E 41 to E 45 ), fixed to said supporting member, and a displaceable electrode ( 245 ), fixed to a displaceable surface that becomes displaced in accordance to a displacement of a lower part of said fourth force transmitting member; wiring, dividing the respective capacitance elements of said first to fourth sensors into a plurality of groups and connecting the plurality of capacitance elements, belonging to the same group, to each other in parallel; and a detection circuit ( 30 ), detecting a force or a moment, acting on said force receiving member, based on a difference between an overall static capacitance value of a set of capacitance elements belonging to one group and an overall static capacitance value of a set of capacitance elements belonging to another group.