Mechanical shock resistant MEMS accelerometer arrangement, associated method, apparatus and system

Patent metadata

Field	Value
Publication number	US-11971428-B2
Application number	US-202318206574-A
Country	US
Kind code	B2
Filing date	Jun 6, 2023
Priority date	Jul 2, 2014
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

An accelerometer arrangement and method are described for determining accelerations of an inground tool. First and second triaxial accelerometers are supported such that a normal sensing axis of the first triaxial accelerometer is at least generally orthogonal to the normal sensing axis of the second triaxial accelerometer for determining the accelerations along the three orthogonal axes based on a combination of sensing axis outputs from one or both of the triaxial accelerometers. A weaker sensing axis of one triaxial accelerometer can be supported at least approximately normal to a weaker sensing axis of another triaxial accelerometer such that the weaker axes are not used. The triaxial accelerometers can be supported such that one axis of one accelerometer can be redundant with respect to another axis of another accelerometer. One triaxial accelerometer can be mounted on a tilted plane with respect to another triaxial accelerometer.

First claim

What is claimed is:

1. An accelerometer arrangement configured for determining accelerations of a device along three at least generally orthogonal axes during an inground operation that exposes the accelerometer arrangement to a mechanical shock and vibration environment, said accelerometer arrangement comprising: a first accelerometer package and a second accelerometer package, each of which includes one or more sensing axes such that the first and second accelerometer packages collectively provide a total of at least four sensing axes for sensing along the three orthogonal axes and at least one of the first accelerometer package and the second accelerometer package includes one sensing axis that is weaker than another sensing axis of that accelerometer package in being more susceptible to mechanical shock and vibration with the first accelerometer package and the second accelerometer package supported such that the weaker axis of one accelerometer package is redundant with respect to another sensing axis in the other accelerometer package; a processor that is configured to select a combination of three sensing axes outputs from the total number of sensing axes to determine the accelerations along said three orthogonal axes without using the weaker sensing axis for determining said accelerations.

2. The accelerometer arrangement of claim 1 , wherein the processor is configured to detect a failure of one or more sensing axes in the combination and, responsive thereto, select a different combination of sensing axes.

3. The accelerometer arrangement of claim 2 , wherein the processor is configured to detect said failure based on a sum of the squares of a set of three outputs for the combination of sensing axes.

4. The accelerometer arrangement of claim 1 , wherein said processor is configured to select the combination of sensing axis outputs based on a priority table.

5. The accelerometer arrangement of claim 4 , wherein the first accelerometer package and the second accelerometer package provide a set of sensing axis combinations based on the total number of sensing axes and said priority table is arranged according to a reliability of at least some of the combinations in the set of sensing axis combinations.

6. The accelerometer arrangement of claim 5 , wherein the processor is configured to detect a failure of one or more sensing axes in the combination and, responsive thereto, loop through a priority table to find a usable combination of sensing axes from the set of sensing axis combinations.

7. The accelerometer arrangement of claim 6 , wherein said processor is configured to loop through the priority table a plurality of times.

8. The accelerometer arrangement of claim 7 , wherein said processor is configured to issue a warning responsive to looping through the priority table said plurality of times without identifying a usable combination.

9. The accelerometer arrangement of claim 6 , wherein the aforerecited combination of sensing axis outputs is identified as a failed combination and the failed combination is re-tested as part of looping through the priority table to find the usable combination.

10. The accelerometer arrangement of claim 9 , wherein said processor is configured to place the failed combination back into service responsive to detecting that the failed combination has become functional.

11. The accelerometer arrangement of claim 1 , supported within a transmitter that is carried by the device.

Assignees

• Merlin Technology Inc

Inventors

• Chau Albert W
• Mercer John E
• Phillips Scott

Classifications

• G01P15/18 Primary

  in two or more dimensions · CPC title

• G01P3/00

  Measuring linear or angular speed; Measuring differences of linear or angular speeds (G01P5/00 - G01P11/00 take precedence; {direction and speed indication G01P13/045}; counting mechanisms G06M) · CPC title

• G01P15/00

  Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration · CPC title

• G01P15/0888

  for indicating angular acceleration · CPC title

• B81B2201/0235

  Accelerometers · CPC title