Transducer calibration apparatus

1. A force transducer calibration apparatus, comprising:

a base;

a pair of end stanchions fixed on the base;

force actuators mounted between the base, the pair of end stanchions, and a transducer holder, the force actuators arranged to exert forces and moments on a transducer mounted in the transducer holder; and

force reaction sensors fixed between the base, the pair of end stanchions, and the transducer holder for measuring forces and moments experienced by the transducer holder.

2. The force transducer calibration apparatus of claim 1 , wherein:

the force actuators and the force reaction sensors are mounted along X, Y and Z axes.

3. The force transducer calibration apparatus of claim 1 , further comprising:

a controller coupled to force actuators and the force reaction sensors for applying selective forces and moments on the transducer, and for recording forces measured by the force reaction sensors.

4. The force transducer calibration apparatus of claim 1 , wherein:

at least one of the force actuators is mounted between the base, the pair of end stanchions and the transducer holder along each of X, Y and Z axes.

5. The force transducer calibration apparatus of claim 1 , wherein at least one of the force reaction sensors comprises:

a rigid tubular member;

a pair of flexures mounted on opposite ends of the tubular member; and

a force transducer coupled between one of the flexures and the tubular member for measuring forces applied by the force reaction sensors on a transducer in the transducer holder.

6. The force transducer calibration apparatus of claim 1 , wherein:

a force actuator of the force actuators comprises a linear actuator having an extensible and retractable rod, the apparatus further comprising:

end connections coupled to one end of the linear actuator and one end of a tubular member for swivelly connecting the force actuator between one of the end stanchions and the transducer holder; and

a compliant member interposed between the tubular member and one of end connections.

7. The force transducer calibration apparatus of claim 1 , further comprising:

each of the force actuators including a load cell measuring a force generated by the force actuator; and

a controller configured to control the forces and moments exerted on the transducer mounted in the transducer holder using feedback from the load cells.

8. The force calibration apparatus of claim 1 , wherein:

the transducer holder comprises an upper lever plate to which each of the force actuators is coupled, and a lower lever plate to which each of the reaction force sensors is coupled; and

the upper lever plate and the lower lever plate are arranged to couple the transducer therebetween.

9. A force transducer calibration apparatus, comprising:

a base;

a first end stanchion fixed on the base;

a second end stanchion fixed on the base;

a first force actuator mounted between the base and a transducer holder, the transducer holder configured to support a transducer;

a first reaction force sensor mounted between the base and the transducer holder;

a second force actuator mounted between the first end stanchion and the transducer holder;

a second reaction force sensor mounted between the first end stanchion and the transducer holder;

a third force actuator mounted between the second end stanchion and the transducer holder; and

a third reaction force sensor mounted between the second end stanchion and the transducer holder; wherein

the first force actuator and the first reaction force sensor are arranged orthogonally to the second force actuator and the second reaction force sensor, and to the third force actuator and the third reaction force sensor.

10. The force transducer calibration apparatus of claim 9 , further comprising:

a controller that controls the first force actuator, the second force actuator, and the third force actuator to exert at least one of a force or a moment on the transducer holder to thereby deform the transducer, and that receives at least one of a force or a moment measured by the first reaction force sensor, the second reaction force sensor, and the third reaction force sensor.

11. The force transducer calibration apparatus of claim 9 , further comprising:

a controller that receives at least one of a force or a moment measured by the first reaction force sensor, the second reaction force sensor, and the third reaction force sensor for comparison with outputs of the transducer mounted in the transducer holder.

12. The force transducer calibration apparatus of claim 9 , further comprising:

a fourth force actuator mounted between the base and the transducer holder;

a fifth force actuator mounted between the base and the transducer holder, the fourth force actuator and the fifth force actuator mounted in parallel with the first force actuator;

a fourth force reaction sensor mounted between the base and the transducer holder;

a fifth force reaction sensor mounted between the base and the transducer holder, the fourth force reaction sensor and the fifth force reaction sensor mounted in parallel with the first force reaction sensor;

a sixth force actuator mounted between the first end stanchion and the transducer holder, the sixth force actuator mounted in parallel with the second force actuator and the second force reaction sensor; and

a sixth force reaction sensor mounted between the second end stanchion and the transducer holder, the sixth force reaction sensor mounted in parallel with the third force actuator and the third force reaction sensor.

13. The force transducer calibration apparatus of claim 9 , wherein:

the transducer holder comprises a first plate and a second plate arranged to couple the transducer therebetween;

each of the first force actuator, the second force actuator, and the third force actuator is coupled to the first plate; and

each of the first force reaction sensor, the second force reaction sensor, and the third force reaction sensor is coupled to the second plate.

14. The force transducer calibration apparatus of claim 9 , further comprising:

each of the first force actuator, the second force actuator, and the third force actuator including a load cell detecting a generated force;

a controller receiving the generated force to control at least one of a force and a moment applied by the first force actuator, the second force actuator, and the third force actuator to the transducer holder.

15. A force transducer calibration apparatus, comprising:

a base;

a first end stanchion affixed to the base;

a second end stanchion affixed to the base;

a transducer holder, the transducer holder coupled to the base by at least one force actuator and at least one reaction force sensor, the transducer holder coupled to the first end stanchion by at least one force actuator and at least one reaction force sensor, and the transducer holder coupled to the second end stanchion by at least one force actuation and at least one reaction force sensor; and

a controller that controls the force actuators to exert at least one of a force or a moment on the transducer holder to thereby deform a transducer, and that receives at least one of a force or a moment measured by the reaction force sensors for comparison with outputs from the transducer.

16. The force transducer calibration apparatus of claim 15 , wherein:

each force actuator includes a load cell; and

the controller is configured to receive output from the load cell from each force actuator to control a level of the at least one of the force or the moment exerted on the transducer holder.

17. The force transducer calibration apparatus of claim 15 , wherein:

the at least one force actuator and the at least one reaction force sensor coupling the transducer holder to the base are arranged about a circumference of a circle;

the at least one force actuator and the at least one reaction force sensor coupling the transducer holder to the first end stanchion are arranged in a first plane; and

the at least one force actuator and the at least one reaction force sensor coupling the transducer holder to the second end stanchion are arranged in a second plane.

18. The force transducer calibration apparatus of claim 17 , wherein:

the first plane and the second plane are coplanar.

19. The force transducer calibration apparatus of claim 15 , wherein a force reaction sensor comprises:

a rigid tubular member;

a pair of flexures mounted on opposite ends of the tubular member; and

a load cell coupled between one of the flexures and the tubular member, the load cell comprising both apply force and reaction force reference cells to measure pushing and pulling forces for calibration of the apparatus.

20. The force transducer calibration apparatus of claim 15 , wherein a force actuator comprises:

a linear actuator having an extensible and retractable rod;

a first end connection coupled to the extensible and retractable rod and to the transducer holder;

a load cell coupled to the linear actuator between the first end connection and the first end connection; and

a second end connection coupled to the linear actuator and to one of the end stanchions through a linear bearing and spring assembly.