Prithwish Das

1
MENG 483 Project Mechatronic System For
Heliostat

• Group 4
• Prithwish Das
• Collin Horvat
• Theresita Martinez
• Robert Slingsby

Fall 2006
2
Outline

• Introduction
• Overview
• Mechatronic Design
• System Assembly
• Total Cost
• Conclusion
• Questions

3
Introduction

• Heliostat Design Team is designing a less costly
  Heliostat
• A Heliostat is a movable mirror that focuss
  light on a central receiver to produce energy.
• Objective of Mechatronics project is to develop a
  prototype to control the mirror.
• A microcontroller, an accelerometer, and a
  stepper motor were used to drive the model.
• System emulates many elements of final design

4
Overview Diagram

• Components used
• MRK Controller Board
• Bread Board
• Stepper Motor
• Accelerometer

Prototype
5
Mechanical Design

• A stepper motor is the primary actuator
• Drives a belt
• Rotates the mirror about its axis
• Mounting system incorporates two aluminum plates
• Stepper motor
• Axel bearings

6
Electrical Design

• Mirror position is acquired by an accelerometer
• Mounted to the back of the mirror
• Fed to the analog-to-digital converter
• System is controlled by the MRK board

Electrical Circuit
7
Software Design

• The system is encapsulated within a while-loop
• Allowing this process to run continually until
  the system is reset
• An Interrupt-service-routine was inserted
• Allows the user to input data at any time during
  operation
• Digital value is compared with an interpolated
  function
• Angular Value Calculated
• Program calculates direction mirror needs to
  travel
• An error value is calculated
• Engages the stepper motor accordingly
• Once the mirror has reached the desired position
  the motor is stopped

System Flow
8
System Assembly

• Machine Shop Allowed for High Tolerances and
  Professional Design.
• Senor Used Sub-par for Final Applications
• Improvement Areas
• Better Signal Conditioning
• Electrical Component Housing
• Second Axis of Rotation
• Ballast Movement

9
Future Control System
Electrolytic Tilt
Rotary Encoder Disk
Inductive Tilt
10
Material Cost and Total Expenses
11
Conclusion

• Objective Defined
• Mechanical Design Selected
• Software Design Completed
• Prototype Works Successfully

12
Questions?
13
Computer Code

• include "MRK.h"
• define TABLE_SIZE 13
• // User Input interrupts
• int in, j, user, error, state, move
• // in receives single character of user input,
  user is final user input (3 char)
• // error is the position error, between desired
  and sensor output
• // state is the stepper motor state, positive
  increase causes positive rotation and vice versa
• // move determines the tolerance, insofar as the
  devices moves to the input position within 2o,
• // then waits for an error gt5o or new user input.
• const char step_sequence 0x01, 0x04, 0x02,
  0x08 //stepper motor sequence
• // user input interrupt- calculates 3 digit user
  input as decimal value
• void char_get (void)
• if (j 1) in fgetchar(SCI0)-'0', j2
• else if (j 2) inin10(fgetchar(SCI0)-'0'),
  j3
• else if (j 3) userin10(fgetchar(SCI0)-'0'),
  j1, move1, fprintf(SCI0," \n User Input d \n
  \r",user)
• // Sensor Input, Calibration
• int x_tableTABLE_SIZE 260, 265, 270, 325,
  370, 430, 490, 560, 620, 650, 675, 720, 730 //
  digital values
• int y_tableTABLE_SIZE 0, 15, 30, 45, 60, 75,
  90, 105, 120, 135, 150, 165, 180

14
Computer Code (contd)

• int main()
• int i, input, angle
• // i is a counter for input averaging.
• // input is the digital conversion of the sensor
  output
• // angle is the computed angle of the mirror
• // Initial Values
• j 1
• user0
• move1
• // Port Organization
• digital_out(OUTPUT,ALL)
• analog_in(RESOLUTION, 10)
• const char segments 0x3f, 0x06, 0x5b, 0x4f,
  0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x67
• // user input interrupt
• setup_sci(SCI0, INTERRUPT, char_get)
• //Read Sensor Input
• while (1)
• // average 16 values
• input 0

15
Computer Code (contd)

• if (move1)
• if (error gt 2)
• statestate1
• else if (error lt-2)
• statestate-1
• else
• state0, move0
• else if (move0)
• if (error gt 10)
• statestate1
• move1
• else if (error lt-10)
• statestate-1
• move1
• else
• state0
• //Motor Output