Manipulator Position Sensor System

• US 20100042357A1
• Filed: 08/15/2008
• Published: 02/18/2010
• Est. Priority Date: 08/15/2008
• Status: Abandoned Application

• Current Assignee: Oceaneering International Incorporated
• Original Assignee: Oceaneering International Incorporated
• Inventors: Holtz, Todd Granger, McCoy, Richard W. JR.
• Application Number:
  US12/192,209
• Publication Number:
  US 20100042357A1
• Time in Patent Office: Days
• US Class Current: 702/141
• CPC Class Codes: B25J 13/088 with position, velocity or acceleration sensors
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: G05B 2219/40547 End effector position using accelerometers in tip

Abstract

A system and method for determining a position of an articulated member with respect to a predetermined plane comprise a multi-axis accelerometer mounted to a first movable member of an articulated set of members. The multi-axis accelerometer produces a sinusoidal signal in proportion to a position of the member with respect to a predetermined set of axes of a predetermined plane. An motion controller operatively in communication with the multi-axis accelerometer determines the angle of inclination as the arctangent of two readings obtained from the accelerometer.

Claims

1. A system for determining a position of an articulated member with respect to a predetermined plane, comprising

a. a multi-axis accelerometer mounted to a first member, the multi-axis accelerometer adapted to produce a sinusoidal signal in proportion to a position of the first member with respect to a predetermined set of axes of a predetermined plane;

and

b. a motion controller operatively in communication with the multi-axis accelerometer, the motion controller adapted to determine a position of the articulated member with respect to the predetermined plane using a value of the sinusoidal signal obtained from the multi-axis accelerometer.

2. The system of claim 1 wherein the multi-axis accelerometer comprises a three-axis accelerometer.

3. The system of claim 1, further comprising a base inclination measuring device.

4. The system of claim 1, wherein the multi-axis accelerometer is adapted for use subsea.

5. The system of claim 1, wherein the multi-axis accelerometer comprises a rate gyro.

6. The system of claim 1, further comprising a data communications network, wherein the motion controller is operatively in communication with the multi-axis accelerometer using the data communications network.

8. An articulated arm, comprising:

a. a first member;

b. a second member movably connected to the first member;

c. a first multi-axis accelerometer mounted to the first member, the first multi-axis accelerometer adapted to produce a sinusoidal signal in proportion to a position of the first member with respect to a predetermined plane;

d. a second multi-axis accelerometer mounted to the second member, the second multi-axis accelerometer adapted to produce a sinusoidal signal in proportion to a position of the second member with respect to the predetermined plane;

e. an motion controller operatively in communication with the first and second multi-axis accelerometers; and

f. a controller operatively in communication with the first member, the second member, and the motion controller.

7. The system of claim 8, wherein the data communications network is selected from the group of data communications networks consisting of Ethernet, Arcnet, CAN, token ring, and RS-485.

9. The articulated arm of claim 8, wherein the first member, the second member, the first multi-axis accelerometer, and the second multi-axis accelerometer are each adapted for use subsea.

10. The articulated arm of claim 8, further comprising a data communications network, wherein the motion controller is operatively in communication with the first and second multi-axis accelerometers using the data communications network.

11. The articulated arm of claim 10, wherein the data communications network is selected from the group of data communications networks consisting of Ethernet, Arcnet, CAN, token ring, and RS-484.

12. A method of determining a position of an articulated member, comprising:

a. obtaining a reading representative of a first axis of a predetermined plane from a multi-axis accelerometer attached to an articulating member;

b. obtaining a reading representative of a second axis of the predetermined plane from the multi-axis accelerometer attached to the articulating member;

c. calculating an angle of inclination of the articulating member with respect to the predetermined plane by;

i. using the readings from the accelerometer as an X axis measurement for the predetermined plane and as a Y axis measurement of the predetermined plane; and

ii. setting the angle of inclination of the member with respect to the predetermined plane as equal to the arctangent of the Y axis measurement over the X axis measurement.

13. The method of claim 12, further comprising:

a. obtaining a predetermined set of accelerometer readings relative to the predetermined plane from an accelerometer mounted to a base to which the articulating member is attached; and

b. using the obtained base readings to adjust the calculated arctangent reading.

14. The method of claim 13, further comprising:

a. providing the arctangent reading to a controller; and

b. using the controller to affect the inclination of the articulating member relative to the predetermined plane based on the arctangent reading.

15. The method of claim 12, wherein the calculating of the angle of inclination of the articulating member with respect to the predetermined plane uses data from a rate gyro for the readings from the accelerometer.