P07106: METEOR Inertial Navigation and Guidance
/public/

7106 Team Work Page

Table of Contents

Overview

Project METOER intends to perform a suborbital test during the summer of 2007. The test will consist of a single stage hybrid rocket launched from a balloon lofted platform. P07106 is responsible for maintaining controlled rocket flight along a flight path from 30km ASL vertically to 100km ASL. The budget for the project is set at US $10,000 and will be controlled by the customer. The group will operate closely with other METEOR groups towards the central goal. The starting point of the project includes some information passed from previous studies. The deliverables include flight ready guidance systems.

Important Reminders

Concepts

INS Mechanical Hardware

Mechanical Concept Overview (ppt)
Mechanical Concept Comparison Matrix (xls))

INS Electrical Hardware

Hardware Overview Concept

Hardware Overview Concept

Interface Concept

Interface Concept

Download Hardware Overview Concept VSD File

uController

Primary candidate: TI TMS320F2811
See uC Selection Page

Interface

Download Interface Concept VSD File

The interface provides a RS422 input and RS232 input/output. The RS422 is passed through a MAX chip for SPI or SCI interface with the uC. The RS422 connector is the same as that specified in by the uIMU. The RS232 i/o is provided by onboard UART or SCI with a standard 9 pin connector.

Power Supply

Preliminary uC Power Use

Primary candidate: Battery

Concerns

Resolved

Flight Control Software

Coming up with help from Dr Crassidis.

INS Testing

Testing Concept

Testing Concept

Empirical testing of the INS's ability to induce actuation and actuator performance is to be done in conjunction with the vertical test team. The issue of syncing up the physical actuation signals and measured response is an issue, since the V-test box has no capability to send out signals. Therefore, it is conceived that the uC will run a tightly timed pre-determined test program that is triggered via the fire signal from launch control. This fire signal will be recorded by the V-test team's box and will provide the reference. Off line oscilloscope / data captures can be then superimposed on the recorded data to provide accurate response times.

.

.

.

IMU

We will be using a IM05-0300C050A35 which feature two additional high G (35) accelerometers on the X and Y axis. The dynamic range for these devices is 35, respectively. These would complement the low G (5) accelerometers on all three axis.

Research

uControllers

See uC Selection Page

Papers

Batteries

Quaternions

http://en.wikibooks.org/wiki/Wikiversity:School_of_Engineering/Dynamics

Deliverables

Workshop 1

Workshop 2

Workshop 3

Workshop 4

Concept Review Week 5

Random Thoughts

Ryan K

Abandoned

Old INS Software

The original INS software concept has been deemed non-realistic. Rocket position will not be determined and kalman filtering will not be done. Quaternions will be used instead of DCM. The work done by Barrios will not be used.
Download Overview VSD File
public/Docs/Concepts/INS_Software.png
The software for the inertial navigation system is broken down into 3 major components: Data Acquisition, Position Determination, and the Thrust Vectoring Control System (TVCS). The TVCS is the combination of Targeting/Correction and Actuation. The TVCS is being designed from scratch, while the other components are based on previous work. There are clean interfaces between the components, so each can be developed and tested as isolated units.

Data Acquisition

The input data to the system is a 35 byte packet from the uIMU device on a RS422 line. The data have to be fetched and converted to meaningful units before it can be used. The data will be buffered in some way before it can be accessed.

Position Determination

See the Position Determination Page

Using the uIMU data passed through a Kalman Filter to reduce noise, an estimate of the current position is formulated by performing a DCM transform on the last known position. This is developed by C. Barrios.

Thrust Vectoring Control System (TVCS)

See the TVCS Page

With a position estimate, the system will need a goal to correct towards. Concepts for targeting include a fixed line at Z=(X,Y) or fixed points in space.

For the fixed line, the system will need to track the line by approaching it as a decreasing rate.

For the fixed points in space, the targeting system will need to choose the next target as the rocket proceeds along the flight path. If all the pre-determined targets are deemed unreachable, a last resort target of maximum altitude will be set directly above the rocket's current position.

The fixed line is the primary contender due to simplicity.

The actuation algorithm translates desired course corrections into the physical signals required to actuate the rocket the desired amount. This depends greatly on the kinimatic model, and the mass of the rocket.

Kalman Filters

See the Kalman Filter Page

Barrios' Thesis

Download Word Doc