Group Members: Mike Oertli Jonathan Karnuth Jason Rancier September 11, 2008 Project Overview Linear accelerator Voltage applied to rails Projectile shorts out rails creating.
Download ReportTranscript Group Members: Mike Oertli Jonathan Karnuth Jason Rancier September 11, 2008 Project Overview Linear accelerator Voltage applied to rails Projectile shorts out rails creating.
Group Members: Mike Oertli Jonathan Karnuth Jason Rancier September 11, 2008 Project Overview Linear accelerator Voltage applied to rails Projectile shorts out rails creating EM field Pneumatic kick-start Projectile accelerates forward Basic Design Conducting rails mounted to non-conducting surface Capacitor array PCB, logic, and UI Conducting metallic projectile Objectives Safety!!! Adjustable voltage from capacitor bank User interface Keypad and LCD Sensor data Velocity calculations Remote/Hands off (Safety!) Approach Split into 3 main areas 1. 2. 3. Railgun Control system User interface Each person focus on one area Communication and compatibility is key Power Supply Brute Force discharge Basic supply, dumps a lot of current directly on rails Simple to design, overkill on capacitance Inefficient, back EMF problems Recharger Supply Complex LC timing based on rails Prone to failure with bad design Requires more capacitors (if polarized are used) Much more efficient Fast recharging Capacitors Capacitance: 610,000µF Voltage: 20VDC 30VDC surge ESR: 2.1mΩ max Type: Electrolytic Number used: ~20 Cost: ~ $400 Capacitor Array Mounted capacitors Connected by switches controlled by logic based on input voltage from user Logic will be based on test shots In enclosed case (Safety) Other possibilities: Manual switches Switch mode power supply Input inductor between array and rails Ramps current to rails Avoid discharging capacitors too fast Rail types Cylindrical Easier to fabricate Fewer pieces Stronger using less material Rectangular Easier to mount Better electrical properties, distributed current Example of rail Conducting rails Materials Rails: Brass Projectile: Aluminum Base: Garolite & Teflon Capacitors: 20x 0.6F 20 v Electrolytic Microcontroller: MSP430 family - 16 bit PCB Power supply Sensors (EM, voltage) Keypad and LCD Brass Rails Composite: ~70% Copper, ~.07% Lead, ~.05% Iron, Remainder Zinc Electrical Conductivity: 28% IACS Electrical Resistance: 6.2µΩ/cm Friction: Very low with Most metals Melting Point: 910oC Inner/Outer Diameter: 0.87”/1” Cost: $58.68 for 36” Projectile Metal: Aluminum Composite: 2011 Temper: T3 Part #: 88615K411 Melting point: 540oC Electrical Conductivity: 45% IACS Electrical Resistivity: 3.8µΩ/cm Diameter: 7/8” Length: ~1” Cost: $17.41/foot Pneumatic Kick-start Avoids spot welding projectile Added kinetic energy Eliminates static friction coefficients Compressed Air/CO2 system Activated by Microcontroller post safety checks Chassis Specs Inner Support Outer Sheath Composite Teflon PTFE Grade G-10/FR4 Crosswise Tensile Strength 3,900 PSI 35,000 PSI Melting Point 335oC ~384oC Max Temp Dielectric Strength 19.7MV/m 15.7MV/m Inner/Outer Diameter .875”/1” 1”/1.375” Cost $9.21 per 12” $92.16 for 39” Part # 8547K29 8668K49 Safety Features Voltage sensors on rails, cap bank, & source Kill power if out of expected range EM Field Sensor Faraday cage if EM field great enough Plexiglas casing Keep user isolated from high voltages and short circuited rails Block Diagram Capacitor Array Power Supply Rails Inductor Kill Switch LEDs MSP430xxxx LCD Keypad Microcontroller MSP430xxxx family Testing on MSP430F169 16-bit for accurate calculation of sensor data Control safety logic based on sensor values Disconnect switches from caps to rails Display values on LCD Software Engineering Interface with Matlab Import sensor data Statistical analysis Display results to user as graphs and tables Maintain records PCB Elements Power supply MSP430 Family Debug/information LEDs LCD (3 or 4 rows) Keypad input Communication with sensors(A/D) Sensor Measure voltage at high sample rate Used for analysis and safety logic Implementation: Voltage transducer Sample @ 10 MHz + Response time < 50μs User Interface Basic keypad Input desired voltage to apply to rails 3 or 4 line LCD on PCB Output sensor data and statistics Basic input user interface If time: Keyboard input Computer monitor with GUI Matlab sensor data analysis Expenses Item # Needed Cost per Total Cost Rails 2x36” $58.68 $117.36 Garolite 2x42” $46.53 $120 Capacitors 20 $20 $400 Projectiles 1’ $17.41 $17.41 PCB 2 $30 $60.00 Controller 3 (donated) $0 Misc/Sensors $300 Estimated Total ~$1014.77 Division of Labor Jonathan Primary Rail Responsibility fabrication & Safety Mike Jason Microcontroller Power systems & & Safety Safety Schedule “Real World” Application Control System for other high voltage applications Accelerator for fun, military, other scientific research Capacitor array for high current burst power systems Sensor to Matlab interface Realization Stay under budget by getting donations Establish primary goals/reasonable functionality Operate within these Add incremental levels of difficulty based on time Plan B Risk: Projectile fuses to rails Discontinuities in the rails and base Arcing- heat/damage to rails Unfamiliarity Sensing systems Matlab interface Recovery Ask for help! Use heavier duty components RTFM Have extra rails and projectiles ready Questions?