P15571- SUNTRACKER Harrison Sprague Jason Yeh Kaung Myat Thu - - PowerPoint PPT Presentation

P15571- SUNTRACKER

Harrison Sprague Jason Yeh Kaung Myat Thu Jacob Halstead Craig Bishop Patrick Chiu Tyler Nicholson

Agenda

• Project Overview
• Key Customer Needs and Derived Eng. Requirements
• Final Design Concept
• Product Development Process
• Results: Major Issues and Findings
• Current State of Project
• Objective Project Evaluation

Project Overview

• Design and implement a complete system

for a satellite receiver dish to automatically track the Sun for the purpose of gathering RF data.

• Customer: Martin Pepe with the Astronomy

Section of the Rochester Academy of Science.

Key Customer Needs and Engineering Metrics

Customer Requirement Engineering Requirement Final Design Performance Met/ unmet

Satellite Focuses

• n Sun’s Position

Azimuth range: 70 - 220 degrees from North Altitude range: 15- 72 degrees from horizon Azimuth range: 7 - 353 degrees from North Altitude range: 10- 74 degrees from horizon Met Software Interface Compatible with RadioEyes and Windows 7 Compatible with RadioEyes, future applications that use ASCOM, and Windows 7 Met Water Proof Construction IP54 and IP67 ratings IP54 and IP67 ratings on all motors, connectors, enclosures, etc. Met Preset/Home Positions Software Interface supports programmed positions Custom positions can be set through RadioEyes and RadioEyes Tasks Met

Key Customer Needs and Engineering Metrics

Customer Requirement Engineering Requirement Final Design Performance Met/ unmet

Positional Accuracy ± 2° Program controlled (default 0.5° accuracy) Motors capable of 0.01° accuracy (non-tracking). Met Limit Azimuth Prevent over-rotation Limit switches with diodes prevent over-rotation. Met Limit Altitude Prevent over- extension/retraction Internal and external limit switches prevent over- extension/retraction. Met System Resists Backlash <1° backlash ~0° backlash from worm-type gearing Met LA provides sufficient force >300 lbf The LA is rated for 400 lbf max; and original calculations overestimated C.O.G. location. Met Slewing Drive provides sufficient torques >150 ft lb rotation >1000 ft lb overturning >200 lb axial load >1000 ft lb rotation ~2000 ft lb overturning >2000lb axial load Met

Key Customer Needs and Engineering Metrics

(1)

• Customer will purchase backup power supply that the team has

recommended and this task will be accomplished. (2)

• Testing on effect of motor noise on the receiver has been

performed in the lab without using shielded cable during MSD 1. The test has no indication of noise present in the collected data. Customer Requirement Engineering Requirement Final Design Performance Met/ unmet

Protect DAQ Runs on backup power for 2 minutes Cannot be tested; backup power supply has not been

• rdered.

Unmet(1) Collect Data Movement of dish does not affect collected data Cannot be tested; new antenna is not installed yet. Unmet (2) Budget of $500 Bill of Materials cannot exceed customer budget Received approval for increased budget of total $1900 Partial Allow Optional Manual Control Allow user to change RA/Dec/Alt/Az Software User Interface is provided but joystick is never attempted. Partial

Original Dish Status

Original 7’ Satellite Dish Linear Actuator Declination Bracket

Final Design (Installed in Ionia)

Slewing Drive Original 7’ Satellite Dish Linear Actuator U-Bracket Skirt covering: Pipe flange adapter plate limit switches LA Mounting Arms Slewing drive Motor Antenna LA Limit Switch

Product Development Process

Results: Major Issues and Findings

Problem Description Solution Shear pin strength (1) Original Shear pins only support 230 lb in double shear. Rework components to accommodate next shear pin size. Shear pin strength (2) Larger shear pin breaks at 1000 lbf (calculated break at 440 lb, rated for 600 lbf) External limit switch implemented to stop full retraction. Pin now serves as “catastrophic loading” protection. Pipe Sizing Pipe was measured to be 3” in diameter on 3 separate trips. Upon installation the pipe is 2.9”. Shims have been added and the pipe-flange will be pinned to the post to prevent rotation.

Results: Major Issues and Findings

Problem Description Solution Communication Flow/Congestion Control Software communication protocol has minimal flow/congestion control resulting in long processing delay Limited report speed of fast communication. Reference Limit Switch Reset Reference Limit Switch Signal cannot be reset by Arduino after capturing the event of limit switch being pressed. Unknown Position Errors Noise in signal lines from slewing drive affected positional feedback (fixed) Noise filter designed with D flip-flop improve all hall signal lines.

Current State of Project

• Completed:

○ Rigid, weatherproof mechanical system ○ Control drivers for calibration and operation ○ Communication with Radio-Eyes for tracking ○ Utilizes ASCOM protocol ○ <0.5° motor precision

• Unmet Functionality

○ Safe position for high wind speed ○ Systematic shutdown during power outage

• Unmet extra functionality

○ ASCOM interface functionality ■ Sidereal Tracking, move axis, pulse guide, sync ○ Manual control with joystick (“Nice-to-have” feature)

Objective Project Evaluations

• Design Strength

○ Degree of rotation is ample, allowing customer to track other objects. ○ The system can withstand the heavy load (overturning moment). ○ Waterproof connectors, sealant and rust-preventative paint improve environmental protection. ○ Increased motor precision is achieved by filtering hall signals and by using shielded cables. ○ Limit switches and diodes prevent damage to the dish and wires. ○ User interface for manual and auto-calibration allows the user to make changes conveniently and prevent human-error without the need to modify the code in several places.

Objective Project Evaluations

• Future Work / Design Weakness

Software ○ ASCOM ■ Sidereal Tracking/ Move Axis/ Pulse Guide / Sync functionality ○ Congestion/Flow control for communication protocol ○ Systematic shutdown and housekeeping ○ TeamViewer Electrical ○ Wiring harness design for Usability (I/O Box for current-limiting diodes) ○ Position feedbacks for daily auto-calibration ○ A single custom board for all electrical designs (Plug-in shield for Arduino)

Objective Project Evaluations

• Future Work / Design Weakness (cont’d)

Electrical ○ Pick a different microcontroller with more interrupts ○ Manual Joystick Control ○ Add or access to local weather station ○ Backup Power Supply ○ Self-Diagnostic Test Plan/Program Mechanical ○ Replace Shear Pins with one larger pin ○ The hardware required for installation should be standardized ○ The pipe flange should be a closer fit and not require shims