Transcript Stepper motor controllers have full/half step mode for different

Color Discriminating
Tracking System
Lloyd Rochester
Sam Duncan
Ben Schulz
Fernando Valentiner
1
Overview of system
2
Different Modules on Board
NTSC Camera with Co-Axial output.
 PC104+ and PCI Frame Grabber.
 30 Frames/ Second at 640x280
resolution.
 Will be completed in Real-Time
embedded systems.

3
Microcontroller Board
HC11
 2 serial inputs for PC104+ and PC.
 NES Controller
 LCD memory mapped, PIC controlled
 Addressing interrupts

4
Example turret
5
Motor circuit

Stepper motor controllers have full/half
step mode for different accuracy, as well
as a range of varying currents for different
speeds.
 Software control can converge smoothly
on a target based on how many steps
away.
 Motors very noisy, inductors have huge
voltage spikes when switching current.
 Steppers will be on a different power
circuit than microcontroller.
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Stepper Motor Specifications
Limited by switching speeds of
hardware controllers
 Can sweep 30 degrees / step in full
step mode,15 degrees / step in half
step mode.
 Travel full field of view ~1 second.
 Torque curve sufficient for turret.

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Digital Signal Processor:
Analog Blackfin or Tigershark DSP
 Motorola 56307 – used in DSP lab
 PC104 Pentium processor

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PIC microcontroller

Pros:
– Very easy to use.

Cons:
– Everything done for us already.
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MC68HC11 Specifications:

8-channel A/D converter (may use external
chip)
 Asynchronous serial communications
interface (SCI)
 Separate synchronous serial peripherals
interface (SPI)
 2 8-bit accumulators (A & B), which can
act as a single 16-bit accumulator (D)
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Specifications continued:
3 input capture lines, 5 output
capture lines
 2 16 bit index registers
 1 stack pointer

11
Microcontroller Board
12
Memory:
Can address 64K memory.
 Possibly have 32k EPROM, 32k
SRAM

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Expanded Mode:
Onboard memory will not be used.
 Expanded mode will be enabled so
HC11 reads from external memory.

14
FPGA
Xilinx Spartan FPGA XC4005E
 Primary Function: Decode address
for Memory Mapping

15
Optional use of FPGA:
Stepper motor controls
 Nintendo controller logic
 Interrupt servicing

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On Board Demonstrations:
The controller will have a control
mode that can be enabled to put the
laser into demo mode.
 3 separate preprogrammed paths:
Circle, Square, and Infinity.

17
The Motor System Problems
Accuracy
 Control
 Position / Calibration

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Accuracy:

Bipolar stepper motors
• 3.8 degree and 1.9 degree Industry Standard

H-Bridge controller required
• Half step implementation realization
19
H-Bridge Controllers

1 pin Step control
• Pulse width for full or half step

2 pin Phase control
• Direction of motor

2 pin Current control
• Handles up to 1.5 amps
• Only need 0.5 to 0.75 amps
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Positioning

Manual control for calibration
• Uses NES game pad

Memory for position reference
• Non volatile memory too slow

Shaft encoders just too inaccurate
21
Software
Task Perform by software in our
design
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Small Software state machine for
the four modes
Manual or Game Pad mode
 Demo mode
 Tracking mode
 Calibration mode

The current mode will be displayed on
the LCD screen
23
Control of the two RS-232
interfaces

Serial interface to the PC104+ to
receive XY coordinates for tracking

Serial Interface to monitor computer,
this is used by the BUFFALO monitor
program
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Human Interface Devices
LCD, it will be used for most of the
output to the user
 Serial Terminal, information can be
transmitted to the terminal for
debugging purposes
 LED lights, Sound, etc.

25
Monitor program

The Motorola BUFFALO monitor
program located locally on EEPROM
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BUFFALO Basic Commands
Command
Description
BF <addr1> <addr2> <data>
Block fill memory with data
LOAD <T>
Download (S-records)
MD [<addr1> [<addr2>]]
Dump memory to terminal
MM [<address>]
Memory modify
HELP
Display monitor commands
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Goals for the project

Minimum: Implement one two-dimensional laser
turret controlled by one Game Pad.
 Goal: Implement one two-dimensional laser turret
controlled either by Demo Mode, Tracking system
or Game Pad.
 Extension: Implement two two-dimensional laser
turrets controlled by Demo Mode, Tracking
System or two Game Pads.
 Maximum: Replace the laser by a more
extravagant device, i.e. dart gun, BB gun, missile,
etc.)
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Objective Timeline

CDR:
Main Board Schematics
Obtain Main board parts
Motor board schematics
Assemble microcontroller board
Get processor running

Milestone 1:
Obtain Motor Board
Assemble Motor board
Finish and test microcontroller hardware
Implement Game Pad interface
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Objective Timeline (Cont)
Milestone 2:
Monitor program running
Implement interface with motors
Real Time Embedded system PC104+ module

Expo:
Run Demo modes for the laser
Receive XY and control laser
Calibrate stepper motors for tracking

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