Remote Controlled Hovercraft Senior Design Project (Harding University)

Summary

This is a collection of PIC code (primarily in C), Multisim schematics, and Protomat designs for the RC Hovercraft Senior Design Project

Examples of Functionality

• PWM Generation (Working)
• Using Input Capture to Analyze an Input PWM Signal (Working)
• Using Input Capture Values to Alter PWM Generation in Real Time (Working, is inside of the Testing folder for now though)

Dependencies

• Input Capture Framework (Working, but needs refinement)
  • InputCapture.h
    • The header file for the main struct and functions used to manipulate all Input Capture modules and analyze the input signals to determine their duty cycle % and frequency
  • InputCapture.c
    • The implementation of all the features located in InputCapture.h
    • The default initialization of each module is to capture each rising and falling edge of a PWM-style square wave using a clock based on Timer1's counter with a prescaler of 1:64 in reference to the system clock (Fcy). Operational ranges are from 1%-99% duty cycle, and from 500mHz-6kHz frequency.
• PWM Generation Framework (Working, but needs refinement)
  • PWM.h
    • The header file for the main struct used to manipulate the motor PWMs and all supporting functions
  • PWM.c
    • The implementation of all supporting functions for the struct representing the motor's PWM modules
    • The default initialization of each module is a 15kHz, 0% duty cycle PWM, the duty cycle and frequency of which can then be managed by the programmer. Operational ranges are from 0%-100% duty cycle, and from ~250Hz-500kHz frequency

Control Subsystems (Work in Progress)

• Input Parsing Subsystem (a framework to utilize input capture)
  • Measuring the time between an input PWM's rising and falling edges to calculate its duty cycle
  • Storing this duty cycle value (as a double) to be used by other functions for thrust and steering calculations
• Output Signal Generation Subsystem (a framework to utilize Output Compare PWM generation)
  • output_signal_generation_driver.c
    • Example uses of the PWM Generation Framework, including how to properly abstract away the need for direct management of internal PIC registers related to PWM generation
    • Shows how PWMs can be generated using the framework to control a two-motor configuration (such as the hovercraft's propulsion system)
• Lift Engine Throttle Control
  • Manipulation of a servo which alters a control surface attached to the throttle of the lift engine, altering the RPM of the engine
  • This is based on input from the remote control
• Kill Switch Subsystem (a framework to manage the hovercraft's kill switch)
  • Automated shutdown of all PWMs for the Propulsion System
  • Turns off the throttle of the Lift System's engine
  • Functionality to turn on the Lift System engine's throttle and resume generation of PWMs when kill switch is no longer engaged

Testing

• Thrust Testing
  • thrust_testing_driver.c
    • Based on output_signal_generation_driver, with modifications made so that the actual propulsion motors can be tested at different speeds to measure the thrust output at each point
  • wireless_controller_driver.c
    • Combination of the PWM and InputCapture dependencies to show that an input capture module reading a signal from the wireless controller can be used to alter an output PWM signal (such as one that would go to the propulsion motors) in real time