SINGLE MOTOR DYNAMIC CALIBRATION UNIT

• US 20140245810A1
• Filed: 03/04/2013
• Published: 09/04/2014
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: Konix, Inc., ROHM Co., Ltd.
• Original Assignee: Kionix Incorporated (ROHM Co., Ltd.)
• Inventors: Adams, Scott G., STIRLING, Nathan L., DeWalt, Luke E., Strait, James E.
• Granted Patent: US 9,751,757 B2
• Time in Patent Office: Days
• US Class Current: 73/1.79
• CPC Class Codes: B81C 99/005 Test apparatus

Abstract

A calibration unit, system, and method for calibrating a device under test are provided. The calibration unit, system, and method use a single axis rotational unit to calibrate devices under test on a test head. The single axis rotation unit is configured to extend at an angle from a known axis. The test head can be designed in the shape of a frustum with multiple sides. The calibration unit, system, and method can use combinations of gravitational excitation, Helmholtz coil excitation, and rotational rate excitation for calibrating the device under test. The calibration unit, system, and method can calibrate a 3 degree for freedom or higher MEMS devices.

Claims

1. A calibration unit comprising:

(a) a single axis rotation unit configured to extend at an angle relative to a known axis and to rotate about a rotation axis;

(b) a test head connected to the single axis rotation unit; and

(c) a position on the test head configured to receive a device under test (DUT);

(d) wherein rotation of the test head about the rotation axis allows for excitation of at least three degrees of freedom of the DUT.

2. The calibration unit of claim 1, wherein the DUT is a triaxis MEMS sensor.

3. The calibration unit of claim 2, wherein the triaxis MEMS sensor includes a magnetometer, gyroscope, accelerometer, pressure sensor, angular accelerometer or a combination thereof.

4. The calibration unit of claim 1, wherein the rotation of the test head about the rotation axis allows for excitation of at least six degrees of freedom of the DUT.

5. The calibration unit of claim 4, wherein the rotation of the test head about the rotation axis allows for excitation of nine degrees of freedom of the DUT.

6. The calibration unit of claim 1, further comprising a measurement unit electrically coupled to the test position.

7. The calibration unit of claim 6, further comprising electrical slip rings to electrically couple the measurement unit to the test position.

8. The calibration unit of claim 1, wherein the known axis is earth'"'"'s Gravitational field.

9. The calibration unit of claim 1, wherein the rotation of the test head about the rotation axis allows for gravitational excitation, Helmholtz coil excitation, or rotational-rate excitation of the at least three degrees of freedom of the DUT.

10. The calibration unit of claim 1, wherein the rotation of the test head about the rotation axis allows for a combination of gravitational excitation, Helmholtz coil excitation, and rotational-rate excitation of at least six degrees of freedom of the DUT.

11. The calibration unit of claim 1, further comprising a computer controlled remote servo motor, coupled to the single axis rotation unit, configured to adjust an angular position, velocity, or acceleration of the single axis rotation unit.

12. The calibration unit of claim 11, wherein the computer controlled remote servo motor is further configured to rotate the single axis rotation unit from a distance such that an electromagnetic field of the motor does not affect the multiple DOF DUT.

13. The calibration unit of claim 1, further comprising:

(a) another position on the test head configured to receive another DUT;

(b) wherein the rotation of the test head about the rotation axis allows for excitation of at least three degrees of freedom of the other DUT substantially concurrently with the excitation of the at least three degrees of freedom of the DUT.

14. A method for configuring devices under test (DUTS), comprising:

(a) loading a device under test (DUT) onto a test head at a loading position;

(b) rotating the test head around a single rotation axis to a first fixed position, wherein the single rotation axis is at an angle relative to a known axis;

(c) exciting the DUT at the first fixed position;

(d) rotating the test head around the single rotation axis to a second fixed position;

(e) exciting the DUT at the second fixed position; and

(f) unloading the DUT at an unloading position;

(g) wherein the exciting the DUT at the first and second positions allows for excitation of at least three degrees of freedom of the DUT.

15. The method of claim 14, wherein the DUT is triaxis MEMS sensors including a magnetometer, gyroscope, accelerometer, or a combination thereof.

16. The method of claim 14, further comprising exciting the DUT as the test head rotates.

17. The method of claim 14, wherein exciting the DUT at the first fixed position happens substantially concurrently with exciting another DUT at the second fixed position.

18. The method of claim 14, wherein the known axis is the earth'"'"'s gravitational field.

19. The method of claim 14, further comprising performing gyroscopic or magnetic sensor testing.

20. The method of claim 14, wherein the exciting the DUT at the first and second positions comprises gravitational excitation, Helmholtz coil excitation, rotational rate excitation, or a combination thereof.

21. A triaxis MEMS calibration system, comprising:

(a) a calibration unit comprising;

(b) a single axis rotation unit configured to extend at an angle relative to a known axis and to rotate about a rotation axis;

(c) a test head connected to the single axis rotation unit; and

(d) a position on the test head configured to receive a device under test (DUT);

(e) wherein rotation of the test head about the rotation axis allows for excitation of at least three degrees of freedom of the DUT; and

(f) a turret handler configured to place the DUT in the position prior to rotation and remove the DUT from the position after rotation.

22. The triaxis MEMS calibration system of claim 21, further comprising a computer controlled remote servo motor, connected to the single axis rotation unit, configured to adjust a position, velocity, or acceleration, or angular acceleration of the single axis rotation unit.

23. The triaxis MEMS calibration system of claim 21, wherein the turret handler is configured to place the DUT on the position substantially concurrently with another position exciting another DUT.

24. The triaxis MEMS calibration system of claim 21, wherein the position is further configured to hold a plurality of DUTs and the turret handler is further configured to place and remove the plurality of DUTs.