Emitted vibration measurement device and method

Claim 1

A method for measuring the vibrational forces produced by a reaction wheel assembly due to the rotor and bearing components and their imbalance and imperfections comprising: providing a large mass base; providing a low mass carriage adapted for carrying said reaction wheel assembly out of contact with said base; supporting said carriage on said base by means of air bearing supports at locations spaced about said carriage to provide a generally frictionless support of said carriage on said base along vertical axes; connecting said carriage and base together by means of load cells at location different from said location of said air bearing supports having a sensing axis in a plane generally parallel to said base so that the only physical coupling between said carriage and base is through said load cells; and analyzing the signals produced by said load cells to identify the rotor components and bearing components causing the vibrational forces.

Claim 2

A method for measuring the vibrational forces produced by a reaction wheel assembly due to the rotor and bearing components and their imbalance and imperfections comprising: providing a large mass base; providing a low mass carriage adapted for carrying said reaction wheel assembly out of contact with said base; supporting said carriage on said base by means of air bearing supports at locations spaced about said carriage to provide a generally frictionless support of said carriage on said base along vertical axes; connecting said carriage and base together by means of load cells at location different from said location of said air bearing supports having a sensing axis in a plane generally parallel to said base so that the only physical coupling between said carriage and base is through said load cells; and analyzing the signals produced by said load cells to identify the rotor components and bearing components causing the vibrational forces.

Claim 5

A method for accurately measuring the vibrational forces produced by a reaction wheel assembly due to the rotor and bearing components comprising: mounting said reaction wheel assembly on a low mass carriage; supporting said carriage on a large mass base by means of air bearings along vertical axes; physically coupling said carriage and base together by means of piezoelectric load cells having their sensing axes arranged in a plane generally parallel to said base; rotating said rotor to cause vibrational forces to be emitted by any imbalances and imperfections in said rotor components and bearing components and to produce output signals in said load cells; and analyzing said output signals from said load cells to determine the components which cause said forces.

Claim 6

A method for accurately measuring the vibrational forces produced by a reaction wheel assembly due to the rotor and bearing components comprising: mounting said reaction wheel assembly on a low mass carriage; supporting said carriage on a large mass base by means of air bearings along vertical axes; physically coupling said carriage and base together by means of piezoelectric load cells having their sensing axes arranged in a plane generally parallel to said base; rotating said rotor to cause vibrational forces to be emitted by any imbalances and imperfections in said rotor components and bearing components and to produce output signals in said load cells; and analyzing said output signals from said load cells to determine the components which cause said forces.

Claim 9

A device for accurately measuring the vibrational forces emitted by a reaction wheel assembly having a rotor and spin bearings due to the imbalances and misalignments in the rotor and inaccuracies and imperfections in the spin bearings, said device comprising: a base means; a plurality of upstanding base blocks carried by said base means being spaced apart in an opposed relation with respect to each other; a carriage adapted for carrying said reaction wheel assembly having a relatively lower mass than said base means; a plurality of carriage bracket means carried by said carriage spaced about said carriage for connection with respective ones of said base blocks; a plurality of air bearing supports supporting said carriage on said base in a generally frictionless manner along vertical axes; a plurality of piezoelectric load cells physically coupling said base blocks and said brackets; said piezoelectric load cells having their sensing axis lying in a plane generally parallel to said base and perpendicular to said vertical axes along which said carriage is supported on said base; said physical coupling of said piezoelectric load cells between said base means and said carriage providing the sole physical coupling between said base means and said carriage when said carriage is frictionlessly supported along said vertical axes on said base means and, said sensing axis of said load cells being disposed in opposing relationship and perpendicular to a rotor axis of said rotor; and means for driving said rotor of said reaction wheel assembly to cause vibrational forces to be emitted from said reaction wheel assembly due to any rotor imbalances and misalignments and any bearing inaccuracies and imperfections; whereby said vibrational forces emitted from said reaction wheel assembly are transmitted from said carriage to said base only through said sensing axes of said piezoelectric load cell.

Claim 10

A device for accurately measuring the vibrational forces emitted by a reaction wheel assembly having a rotor and spin bearings due to the imbalances and misalignments in the rotor and inaccuracies and imperfections in the spin bearings, said device comprising: a base means; a plurality of upstanding base blocks carried by said base means being spaced apart in an opposed relation with respect to each other; a carriage adapted for carrying said reaction wheel assembly having a relatively lower mass than said base means; a plurality of carriage bracket means carried by said carriage spaced about said carriage for connection with respective ones of said base blocks; a plurality of air bearing supports supporting said carriage on said base in a generally frictionless manner along vertical axes; a plurality of piezoelectric load cells physically coupling said base blocks and said brackets; said piezoelectric load cells having their sensing axis lying in a plane generally parallel to said base and perpendicular to said vertical axes along which said carriage is supported on said base; said physical coupling of said piezoelectric load cells between said base means and said carriage providing the sole physical coupling between said base means and said carriage when said carriage is frictionlessly supported along said vertical axes on said base means and, said sensing axis of said load cells being disposed in opposing relationship and perpendicular to a rotor axis of said rotor; and means for driving said rotor of said reaction wheel assembly to cause vibrational forces to be emitted from said reaction wheel assembly due to any rotor imbalances and misalignments and any bearing inaccuracies and imperfections; whereby said vibrational forces emitted from said reaction wheel assembly are transmitted from said carriage to said base only through said sensing axes of said piezoelectric load cell.

Claim 18

A device for accurately measuring vibrational forces comprising: a base means; a plurality of upstanding base blocks carried by said base means, said base blocks being spaced apart in an opposed relation with respect to each other; a carriage adapted to carry a member producing vibrational forces; a plurality of carriage bracket means carried by said carriage at first locations, said bracket means spaced about said carriage for connection with respective ones of said base blocks; a plurality of air bearing supports supporting said carrige or said base means in a generally frictionless manner along vertical axes, said air bearing supports being disposed at spaced locations about said carriage different from said first locations; a plurality of piezoelectric load cells, each said load cell coupling a said base block to a said bracket means; and said piezoelectric load cells having their sensing axis lying in a plane generally parallel to said base means and perpendicular to said vertical axes along which said carriage is supported on said base means.

Claim 19

A device for accurately measuring vibrational forces comprising: a base means; a plurality of upstanding base blocks carried by said base means, said base blocks being spaced apart in an opposed relation with respect to each other; a carriage adapted to carry a member producing vibrational forces; a plurality of carriage bracket means carried by said carriage at first locations, said bracket means spaced about said carriage for connection with respective ones of said base blocks; a plurality of air bearing supports supporting said carrige or said base means in a generally frictionless manner along vertical axes, said air bearing supports being disposed at spaced locations about said carriage different from said first locations; a plurality of piezoelectric load cells, each said load cell coupling a said base block to a said bracket means; and said piezoelectric load cells having their sensing axis lying in a plane generally parallel to said base means and perpendicular to said vertical axes along which said carriage is supported on said base means.