Transcript P10203 LV1 motor controller Final Review May 14, 2010

P10203 LV1 MOTOR CONTROLLER
FINAL REVIEW
MAY 14, 2010
Electrical: Kory Williams, Adam Gillon, Oladipo Tokunboh
Mechanical: Louis Shogry, Andrew Krall
Agenda
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Project Overview
Customer Needs
Design Specifications
Project Status
Schedule
Budget
Testing Results
Issues and Findings
Conclusions and Future Work
Project Overview
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The purpose of the LV1 motor controller project was
to reduce the cost of the previous generation RP1
motor controller while also improving size,
manufacturability and appearance.
Our team was to work closely with the other
coincident LV1 projects (P10201, P10202, P10205)
to create a functional robotic land vehicle with the
capability to transport a 1 kg payload.
Customer Needs
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The controller is easy to manufacture and assemble.
The controller is modular, (can be configured in several different options to support varied
functionality).
The controller has a low risk implementation and is stand-alone.
The controller is able to properly interface with the other modules of the Land Vehicle
Platform.
The controller is able to be used by first year mechanical/electrical engineering students.
The controller is able to make the platform move with sufficient agility and controllability.
The new design shall improve upon the aesthetics of the RP1.
The controller makes effective use of the space provided by the Chassis.
The new design is cost effective, (cheaper than the RP1 with the same, or improved
performance characteristics).
The controller is durable and can withstand repeated use with minimal maintenance.
The controller has a reasonable battery life.
The controller is able to be upgraded by future Senior Design teams with little redesign or
component replacement needed.
The controller makes use of Prior Generations Designs and Research.
Design Specifications
Engr.
Spec #
Customer Need
Unit of
Measure
Specification
Marginal
Value
Ideal
Value
Comments
General Design
ES1
ES2
ES3
ES4
CN9, CN13
CN5, CN10
CN3, CN10
CN4, CN7, CN8
Total cost of Controller.
Mounted Controller drop test surviveability.
All sensitive components are separated from Noise
Distance between controller outputs and interfaces.
$
Feet
Centimeters
Centimeters
$475.00
3
> 4 cm
< 30cm
$400.00
5
> 8 cm
< 15cm
Reduction from $511 in RP1
Based upon table-top fall
Will conform to available dimensions
Will conform to available dimensions
ES5
CN10
Operating Temperature of Components in Controller.
Degrees
Celcius
125 C
100 C
Maximum temperature of any individual component in the
system. This is the junction temperature inferred from the
outer temperature of the case.
KB
75kB
50kB
50kB is about 40% of the available memory on the controller.
Count
14
20
Quantification of all inputs and outputs to/from the system
Based upon available data rate range of wireless technology
used by P10205
Processing Subsystem
ES6
CN4, CN12
Amount of memory on controller.
ES7
CN4, CN12
Number of I/O able to be controlled.
ES8
CN4, CN6, CN12
Bandwidth required at input to controller.
Data Rate
50 Kbps
250kbps
Data Format at Input to Controller.
Programming Language used to program Controller.
Latency of Command Throughput.
Format
Language
ms
8N1 Bits
C++
150 ms
8N1 Bits Dictated by onboard software from RP1
C, C++,
100 ms Time required to process input and output control signals
ES9 CN4
ES10 CN4, CN12, CN13
ES11 CN4, CN6
Correction Subsystem
ES12 CN6
Degrees of Freedom maintained by Controller.
Steering,
2
2
1
1
Motor Driver(s)
ES13 CN4, CN6
Controller interfaces with motor modules independently.
Boolean
Power Distribution Subsystem
ES14 CN11
Power Consumption of the Processing Sub-system.
Watts
< 5W
< 3W
This value refers to the power consumption of the entire
controller. This does not include the consumption of the motor
modules.
System Architecture
Product Development Process
Phase 0: Planning
•Define Project Goal
•Develop Customer Requirements
•Define Engineering Metrics
Phase 1: Concept Selection
•2 Rounds of PUGH Concept Selection
•Analysis of existing RP1
Phase 2: Product Design
•Pspice Simulations
•Validation using engineering calculations
Phase 3: Final Design
•Detailed Schematics and Layout
•Finalized BOM
Phase 4: Building
•Order parts
•Assembly and mounting
Phase 5: Testing
•Subsystem
•Interfacing
MSD1
0
1
MSD 2
2
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5
Current
State
Project Status
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Controller is able to function independently of the
other modules on the LV1 platform.
Controller is able to communicate over the Wireless
communications link with the GUI.
Controller is able to drive all four motors at the same
time (unmounted)
Battery is compatible with regulation circuits on the
controller.
Schedule
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Interface testing with Wireless team completed on
schedule.
Interface testing with Chassis and Motor Modules
fell behind 2 weeks.
Full System testing is still incomplete. Final tests will
be run when the platform can be run on the ground.
Budget
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Total Cost of Two Controller Units is $798.00
including shipping for parts and components. (20%
reduction from the RP1).
Total cost does not include encoder cables that were
purchased late due to a miscommunication with the
motor module team.
Some components like the mounting plate for the
PID controller can be removed from BOM since they
were not used.
Testing Results
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Subsystem Testing
Voltage Regulator boards are functional and able to limit
an 8.4V input to 5V (Logic) and 5.93V (Servo).
 Motor Driver boards are able to amplify a PWM input
signal and provide the stall current condition (1.6A).
FWD/REV and speed control are confirmed.
 I2C interface between Control Units is confirmed and
communications between the devices has been established.
 Controller interfaces with the GUI via a wired connection.
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Testing Results (cont)
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Interface Testing
Communications with the Wireless Team has been
established using the GUI to send motor control commands.
• Using the GUI, we are able to move the drive motors
bidirectionally and with varied speed. Servos are also able
to be rotated 180 degrees.
• Battery successfully powers up regulator circuits and
provides enough voltage to maintain constant Logic and
Servo Levels.
• Encoder Functionality has not yet been evaluated since
motors cannot be driven in contact to the ground.
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Issues and Findings
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As a subsystem, the controller can operate as
intended in the design.
Full System Integration has not yet been established
since we are unable to move the robot on the
ground.
When the motors try to overcome static friction,
there is a large risk of permanent damage to both
the drive motor and the motor driver circuitry due to
a large current draw. Current limiting circuits may
be required in order to obtain proper control of the
platform.
Conclusions and Future Work
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There are some additional layout issues that can be
resolved to make external connections easier.
The thermal coating considerations were dropped
due to time restrictions and limited resources.
Additional software knowledge is required for
alteration of GUI or program of MCU Unit and PID
Controller.
Linear Regulators could be replaced with switching
regulators to reduce power loss.