MakerBotControlSystem
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=== Variable Definition Table === | === Variable Definition Table === | ||
+ | |||
+ | ==== Global Variables === | ||
{| border="1" | {| border="1" | ||
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|Room Ambient temperature | |Room Ambient temperature | ||
|} | |} | ||
+ | |||
+ | ==== Build Platform and Chamber ==== | ||
{| border="1" | {| border="1" | ||
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|Celcius | |Celcius | ||
|Build Platform temperature, ADC sampled thermistor | |Build Platform temperature, ADC sampled thermistor | ||
+ | |- | ||
+ | |M<sub>bp</sub> | ||
+ | |grams | ||
+ | |Build Platform mass, including deposited material over time. | ||
|- | |- | ||
+ | |rowspan="1"|Build Chamber | ||
|T<sub>bc</sub> | |T<sub>bc</sub> | ||
|Celcius | |Celcius | ||
|Build Chamber temperature, ADC sampled thermistor | |Build Chamber temperature, ADC sampled thermistor | ||
|} | |} | ||
+ | |||
+ | ==== Extruder ==== | ||
{| border="1" | {| border="1" | ||
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|Exit Nozzle diameter | |Exit Nozzle diameter | ||
|} | |} | ||
+ | |||
+ | ==== Motion Control ==== | ||
{| border="1" | {| border="1" |
Revision as of 18:30, 8 May 2010
Contents |
MakerBot: Control System Design, Implementation and Characterization
Time to brush off some of that rusty old control system design knowledge I once majored in.
Goals
My goals will be to:
- Describe the MakerBot thermal, electrical and mechanical system in terms of a state-space model.
- Model said system using the GNU Octave free open-source software (FOSS) suite of tools.
- Design test and measurement criteria and data to generate a set of parameter estimation functions to calibrate the control system model.
- Generate discrete-time state-space octave model.
- Implement discrete-time algorithm using microcontroller or DSP (as required).
The Model
Controllable Parameters
Extruder
- Heater On/Off (PWM control code)
- DC Motor Voltage (PWM control code)
- Nozzle aperture diameter (fixed)
- Incoming filament diameter (fixed)
X Axis
- Stepper Velocity (step rate)
Y Axis
- Stepper Velocity (step rate)
Z Axis
- Stepper Velocity (step rate)
Observable Parameters
Extruder
- Relative Nozzle Temperature (thermistor ADC code)
- Closed loop
- Calibrated Nozzle Temperature (thermocouple based digital thermometer)
- Open loop
- Incoming filament position (with encoder wheel/sensor)
- Closed loop
- Incoming filament travel (callipers)
- Open loop
- Outgoing filament diameter (callipers)
- Open loop
- Outgoing filament length (callipers)
- Open loop
- Outgoing filament mass (scale)
- Open loop
- Possibly closed loop with build platform integrated weight cells.
X Axis
- Endstop activation
- Closed loop
- Position (ruler)
- Open loop
Y Axis
- Endstop activation
- Closed loop
- Position (ruler)
- Open loop
Z Axis
- Endstop activation
- Closed loop
- Position (ruler)
- Open loop
Variable Definition Table
= Global Variables
Subsystem | Variable | Units | Description |
---|---|---|---|
Global | Tra | Celcius | Room Ambient temperature |
Build Platform and Chamber
Subsystem | Variable | Units | Description |
---|---|---|---|
Build Platform | Vbp | Volts | Build Platform, PWM generated voltage through nichrome |
Tbp | Celcius | Build Platform temperature, ADC sampled thermistor | |
Mbp | grams | Build Platform mass, including deposited material over time. | |
Build Chamber | Tbc | Celcius | Build Chamber temperature, ADC sampled thermistor |
Extruder
Subsystem | Variable | Units | Description |
---|---|---|---|
Extruder | Vem | Volts | Extruder Motor, geared DC, PWM generated voltage |
θwe | Degrees | Rotational Extruder displacement of drive motor shaft. | |
Veh | Volts | Extruder Heater, PWM generated voltage through nichrome | |
Ten | Celcius | Extruder nozzle temperature, ADC sampled thermistor | |
Dif | mm | Input Filament diameter, entering extruder | |
Def | mm | Exiting Filament diameter, emerging from nozzle | |
Den | mm | Exit Nozzle diameter |
Motion Control
Subsystem | Variable | Units | Description |
---|---|---|---|
X Axis | Vlx | mm/s | Linear X velocity |
Dlx | mm | Linear X position | |
θwx | Degrees | Rotational X displacement of drive motor shaft. | |
Y Axis | Vly | mm/s | Linear Y velocity |
Dly | mm | Linear Y position | |
θwy | Degrees | Rotational Y displacement of drive motor shaft. | |
Z Axis | Vlz | mm/s | Linear Z velocity |
Dlz | mm | Linear Z position | |
θwz | Degrees | Rotational Z displacement of drive motor shaft. |
References
Online Course Material
MIT OpenCourseWare
Electrical Engineering and Computer Science
- 6.011 Introduction to Communication, Control, and Signal Processing
- 6.231 Dynamic Programming and Stochastic Control
- 6.241 Dynamic Systems & Control
- 6.243J / 2.156J / 16.337J Dynamics of Nonlinear Systems
- 6.245 Multivariable Control Systems
- 6.091 Hands-On Introduction to Electrical Engineering Lab Skills
- 6.152J / 3.155J Micro/Nano Processing Technology
- 6.302 Feedback Systems
- 6.341 Discrete-Time Signal Processing
- 6.432 Stochastic Processes, Detection, and Estimation
- 6.435 System Identification
- 6.774 Physics of Microfabrication: Front End Processing
- 6.777J / 2.372J Design and Fabrication of Microelectromechanical Devices
Mechanical Engineering
- 2.001 Mechanics & Materials I
- 2.002 Mechanics and Materials II
- 2.003 Modeling Dynamics and Control I
- 2.003J / 1.053J Dynamics and Control I
- 2.004 Systems, Modeling, and Control II
- 2.12 Introduction to Robotics
- 2.72 Elements of Mechanical Design
- 2.067 Advanced Structural Dynamics and Acoustics (13.811)
- 2.093 Computer Methods in Dynamics
- 2.094 Finite Element Analysis of Solids and Fluids
- 2.158J / 1.128J / 16.940J Computational Geometry
- 2.171 Analysis and Design of Digital Control Systems
- 2.26 Compressible Fluid Dynamics
- 2.830J / 6.780J / ESD.63J Control of Manufacturing Processes (SMA 6303)
Materials Science and Engineering
- 3.00 Thermodynamics of Materials
- 3.016 Mathematics for Materials Scientists and Engineers
- 3.032 Mechanical Behavior of Materials
- 3.044 Materials Processing
- 3.063 Polymer Physics
- 3.064 Polymer Engineering
- 3.14 Physical Metallurgy
- 3.185 Transport Phenomena in Materials Engineering
- 3.A04 Modern Blacksmithing and Physical Metallurgy
- 3.11 Mechanics of Materials
- 3.20 Materials at Equilibrium (SMA 5111)
- 3.205 Thermodynamics and Kinetics of Materials
- 3.21 Kinetic Processes in Materials
- 3.22 Mechanical Behavior of Materials
- 3.225 Electronic and Mechanical Properties of Materials