Dodecahedron Inertial Navigation Network

Mahdi Jadaliha

Introduction

To estimate position has always been a challenge for the mankind, be it navigating spaceships using Inertial Navigation Systems (INSs), or simply crossing the desert using compass or stars to find his direction.

Different applications call for different methods, however, the main goal is the same in all navigation: to estimate or measure position or some of its derivatives.

Problem Definition

I have been several years in a robotic team. My duty was finding position of robots and obstacles.

since an INS refers to no real-world item beyond itself. It is therefore self-contained, immune to jamming and deception, non-radiating, and a good candidate for position estimation in Autonomous Mobile Robots.

Problems with INS

Can’t measure speed directly

Can’t measure yaw directly

It is very dependant to temperature

* please refer to http://en.wikipedia.org/wiki/Inertial_navigation_system for more information.

Solved with Dodecahedron

Can measure speed directlyDodecahedron calculates speed by measuring gyroscopic

torque on different facets.

Can measure yaw directlyadvanced compassing mechanism is developed to estimate the

position of magnetic source(by scattered measurements on the surface of dodecahedron) , therefore we can find magnetic field of earth even in a complicated environment.

It is not very dependant to temperaturemeasuring quantities with two sensors in opposite direction

reduces the effect of temperature on their biases effectively.

Since 2007, I have focused all my efforts on developing a sensor network to determine the position with measuring inertial data from low-cost low-precision inertial sensors. I have made a small and low-cost Inertial Sensor Network, especially with application in Autonomous Vehicles. I made it completely by myself, from designing steps to soldering and programming its DSP.

I have DONE every steps of this project by myself

Designing Micro controller and analog circuits by Altium (Protel)

Designing PCB board by Altium (Protel)

Soldering

Programming Microcontroller by C (MPLAB)

Programming data accusation software on PC by Delphi

Designing Microcontroller and Analog Circuits

Designing PCB

Soldering

Programming Microcontroller

I tried 3 times to make best measurements

X,Y axes gyroscope DSP Microcontroller

Z axis gyroscope

And Thermom

eterX, Y axis Magnetometers

3 ax

es A

ccel

erom

eter

Main component of IMU modules

Each modules is a complete Inertial Measurement Unit (IMU). It has 3 perpendicular axes of measurement for Accelerometers and Gyroscopes.

Each module (pentagonal) has capabilities equal to Xsense commercial Products.(http://www.xsens.com/)

However I designed this Dodecahedron for Autonomous vehicle, the modules can be used in different configuration for different propose.

Motion Tracking is one of the most popular use of these modules.

Motion tracker

* please refer to very exciting Video http://www.moven.com/Static/Documents/UserUpload/Moven_movie/product_reel2009.wmv for more information.

From: www.xsense.com

Dodecahedron Hardware complexity

It is made from 770 discreet electrical component

Measures 108 Sensory Quantity

It uses Distributed Processing with 12 DSP

Support RS485, RS232, SPI, CAN to communicate

Advanced Data Structure to reduce communication faults

Manage all process by Interrupts in an event trigger manner to reduce power consumption

Uses DMA to decrease process load

Thank you for your Patience

Geometrical shape

Appendix: Platonic SolidsName V F E F-Type Truncation Dualtetrahedron 4 4 6 triangles truncated tetrahedron tetrahedroncube 8 6 12 squares truncated cube octahedronoctahedron 6 8 12 triangles truncated octahedron cubedodecahedron 20 12 30 pentagons truncated dodecahedron icosahedronicosahedron 12 20 30 triangles truncated icosahedron odecahedron

tetrahedron cube octahedron dodecahedron icosahedron

All vertices, edge mid-points and face mid-points lie on concentric spheres All faces are the same shape and are all regular polygons Thus all edges are equal in length and face corners equal in angle. Duals are also all Plationic Solids. The cube is also called a hexahedron

[1] http://www.cit.gu.edu.au/~anthony/graphics/polyhedra/