System and method for calculating the orientation of a device

Abstract

A system and method for determining orientation of a vehicle is provided. The method includes the steps of providing a vehicle having a hinge joint such that sections of the chassis are capable of rotation with respect to each other. A first and second wheel is mounted to one and the other of the chassis sections, respectively. Vehicle geometric data defining a distance between the hinge joint and the centers of the first and second wheels, respectively, and the diameter of the wheels is provided. Surface geometric data defining the curvature of the surface can be provided. The angle of rotation about the hinge joint is measured. An orientation of the vehicle relative to the surface based on the vehicle geometric date, the surface geometric data, and the measured angle of rotation can be determined. A system and method for determining the orientation of an object is also provided.

The invention claimed is: 
     
       1. A method for determining orientation of a vehicle relative to a surface having defined geometric data that represents a curvature of the surface, the method comprising the steps of:
 measuring an angle of rotation about a hinge joint that is part of the vehicle, wherein the vehicle is configured to travel along the surface; 
 determining the orientation of the vehicle relative to the surface based on vehicle geometric data, the surface geometric data and the measured angle of rotation using a processor located on board the vehicle; and 
 controlling operation of the vehicle in view of the determined orientation using the processor, 
 wherein the surface comprises a cylindrical pipe and the step of determining the orientation of the vehicle corresponds to determining one orientation out of four possible orientations relative to a centerline of the cylindrical pipe and the method further includes the step of storing an original orientation of the vehicle and all further orientation changes of the vehicle and determining which one of the four possible orientations is a true orientation of the vehicle based on the original orientation and all the further orientation changes of the vehicle. 
 
     
     
       2. The method of  claim 1 , wherein the hinge joint is disposed between a first chassis section and a second chassis section such that the first and second chassis sections are capable of rotation with respect to each other in at least one direction. 
     
     
       3. The method of  claim 2 , wherein the first chassis section includes a first wheel mounted thereto and the second chassis section includes a second wheel mounted thereto. 
     
     
       4. The method of  claim 3 , wherein the vehicle geometric data defines at least a distance between the hinge joint and a center of the first and second wheels, respectively, and a diameter of each of the wheels. 
     
     
       5. The method of  claim 3 , wherein the first wheel is a magnetic drive wheel. 
     
     
       6. The method of  claim 3 , wherein the second wheel is a magnetic drive wheel that is configured to move in at least two directions. 
     
     
       7. The method of  claim 1 , wherein the step of measuring the angle of rotation about the hinge joint comprises providing a sensor in the vehicle, the sensor being configured to measure the angle of rotation about the hinge joint. 
     
     
       8. The method of  claim 1 , wherein the vehicle is configured to transverse a curved surface in a helical path. 
     
     
       9. The method of  claim 8 , further including the step of determining when every loop of the helical path ends and a next loop starts by analyzing a plurality of sensor readings including wheel encoders and inertial measurement unit (IMU) data. 
     
     
       10. The method of  claim 9 , wherein the IMU data includes data obtained from accelerometers, gyroscopes and magnetometers. 
     
     
       11. The method of  claim 1 , wherein the surface comprises a cylindrical pipe and the step of determining the orientation of the vehicle corresponds to determining four possible orientations relative to a centerline of the cylindrical pipe and the method further includes the step of recording previous measurements of the hinge angle and determining which of the four possible orientations is a true orientation of the vehicle based on a start orientation and previous orientation changes of the vehicle. 
     
     
       12. The method of  claim 8 , wherein the vehicle includes a on board processor that operates is further configured to operate so as to control a helical pitch and ensure that loops of the helix are spaced a constant distance from one another. 
     
     
       13. The method of  claim 3 , wherein the first wheel is a magnetic drive wheel that rotates about a first axis and the second wheel is a magnetic omni-wheel that rotates about a second axis that is perpendicular to the first axis, the omni-wheel including a plurality of rollers that are located about a periphery of the omni-wheel, each roller rotating in a same direction as rotation of the magnetic drive wheel. 
     
     
       14. The method of  claim 1 , wherein the hinge includes first and second rotation stops that are configured to prevent unintentional rotation about the hinge. 
     
     
       15. The method of  claim 14 , wherein the hinge joint is disposed between a first chassis section and a second chassis section such that the first and second chassis sections are capable of rotation with respect to each other in at least one direction, wherein the first and second rotation stops are mating surfaces on each of the first and second chassis section sections, respectively. 
     
     
       16. A method for determining a diameter of a curved structure over which a vehicle travels comprising the steps of:
 determining geometric data of the vehicle;   determining an orientation of the vehicle relative to the curved structure; and   measuring an angle of rotation about a hinge joint that is part of the vehicle to determine the diameter of the curved structure.   
     
     
       17. The method of  claim 16 , further including the step of determining a maximum angle of rotation that has been measured and the step of determining the diameter of the curved structure is based on the recorded maximum angle of rotation and the geometric data of the vehicle. 
     
     
       18. The method of  claim 16 , wherein the curved structure comprises a pipe. 
     
     
       19. A system for determining orientation of a vehicle relative to a surface having defined geometric data that represents a curvature of the surface comprising:
 a drivable vehicle including:
 a hinge joint connecting a first part of the vehicle to a second part of the vehicle such that the first and second parts are capable of movement with respect to one another as the vehicle is driven across the surface, the movement of the first and second parts being translated into rotation of the hinge joint; 
 a sensor configured to measure an angle of rotation about the hinge joint; and 
 a processor configured to determine an orientation of the vehicle relative to the surface based on defined vehicle geometric data, the defined geometric data of the surface, and a measured angle of rotation about the hinge joint and wherein the processor is configured to control operation of the vehicle in view of a determined orientation, 
 
 wherein the surface comprises a cylindrical pipe, and 
 wherein to determine the orientation of the vehicle, the processor is further configured to determine one orientation out of four possible orientations relative to a centerline of the cylindrical pipe by storing an original orientation of the vehicle and all further orientation changes of the vehicle and determining which one of the four possible orientations is a true orientation of the vehicle based on the original orientation and all the further orientation changes of the vehicle. 
 
     
     
       20. The system of  claim 19 , wherein the hinge is selected from the group consisting of: a knuckle/pin hinge, a ball and detent hinge, and a length of flexible material. 
     
     
       21. The system of  claim 19 , wherein the first part comprises a first chassis section and the second part comprises a second chassis section. 
     
     
       22. The system of  claim 21 , wherein the first chassis section includes a first wheel mounted thereto and the second chassis section includes a second wheel mounted thereto. 
     
     
       23. The system of  claim 19 , wherein the defined vehicle geometric data includes at least a distance between the hinge joint and a center of the first and second wheels, respectively, and a diameter of the wheels. 
     
     
       24. The system of  claim 19 , wherein the first wheel comprises a magnetic drive wheel and a second wheel comprises a magnetic drive wheel. 
     
     
       25. The system of  claim 19 , wherein the vehicle is capable of traversing a curved surface in a helical pattern.