Preliminary Design Report. Project Title: Human-Powered Sub. Team Name: Depth Perception

Transcription

1 EEL 4924 Electrical Engineering Design (Senior Design) Preliminary Design Report 31 January 2011 Project Title: Team Name: Depth Perception Team Members: Name: Jared Korn Name: Alex Lizardo

2 Page 2/6 Table of Contents Title/cover...Page 1 Table of Contents...Page 2 Abstract...Page 3 Introduction...Page 3 Features...Page 4 Technical Objectives...Page 4 Gantt Chart... Page 6

3 Page 3/6 Abstract Our project consists of collaborating with the UF Human Powered Sub team to design, test, and build the electronics systems for the sub. Ideally we will be able to have automatic pitch control, automatic yaw control with the ability to switch to manual control, a lighted display, and thrust efficiency control. This will all be powered by LiPo batteries. Two pressure sensors will detect the pitch of the sub while a webcam with image processing hardware will track a string of lights on the floor of the pool to detect yaw. Four servo motors will control two elevators for pitch adjustment and two fins for yaw adjustment. The display will show depth, speed, yaw, and battery life. A linear actuator will control the attack angle of the propeller blades to provide maximum thrust. Introduction The UF team consists of several Mechanical Engineering students who are designing and building a submarine for a competition. Currently the entire project is funded through sponsorship so any electronics should be available to us at no cost. The sub is powered only by human power but will contain several electrical components that we will be designing and building. This project is going to involve digital and analog hardware design including amplification and filtering as well as power supply design. There will be two main software designs: one for the microcontroller and one for the embedded processor. Lastly, the entire electronic system must be waterproof while still being connected to external sensors and motors. This project will always be under constant review for design requirements and needs as the mechanical team progresses and builds the sub. However, the final product will still be the result of challenging electrical engineering work sufficient for a senior design project. This is a picture of the most recent sub design

4 Page 4/6 Features Automatic Pitch control - Two pressure sensors located in the front and back ends of the sub will sense the pitch of the sub and send this information to a microcontroller which will control 2 servo motors to correct the pitch. Manual Yaw control - A joystick will be accessible to the driver to manually turn the sub left and right in case of failure of the automatic yaw control. The joystick will send signals to the microcontroller to adjust servos attached to fins to turn left or right. Display - A backlit LCD with on/off functionality will provide important information to the driver if needed and will stay unlit when not. The information will include current depth, speed, possibly yaw, and battery life. Other information may be displayed if a need arises. Power system - LiPo batteries are available as the power source for the electronics. Regulation of voltage levels and consideration of power consumption by various components will have to be designed to ensure the electronics stay protected as well as functioning for a period of time. Thrust efficiency - A sensor (most likely hall-effect) will detect the rpm of the driveshaft and relay this information to a microcontroller. The microcontroller with move a linear actuator attached to the propeller blades that will adjust the angle proportional to the speed. Automatic Yaw control - This will be the most challenging aspect and will involve the most hardware and software. A webcam attached to an on board computer with imaging processing software will view a string of lights on the bottom of the pool and send this information to a microcontroller. The microcontroller will then adjust servo motors to turn left or right depending on the location of the lights. Technical Objectives -Digital Hardware Components- We will be using a PIC microcontroller as the main processor for our system. It will be responsible for updating the LCD and controlling all the motors and linear actuator. It will also monitor all the sensors and perform the simple calculations for the LCD display values. The servos are digitally controlled. The other chunk of digital hardware is the image processing portion. An embedded processor attached to a USB webcam will do the image processing and send the important information to the microcontroller. -Analog Hardware Components- The analog hardware will consist of filters, amps, and the power supply management circuits. The amplifiers and filters will allow small signal analog sensor outputs to be read by the A/D on microcontroller accurately and at a desirable resolution. The power circuitry will be able to provide the necessary supply voltages and also protect the sensitive electronics from damage through low-voltage protection. There will have to be a way of sensing the remaining power.

5 Page 5/6 -Micro Controller Software- Efficient code will be compiled to update the LCD when needed, interpret the sensor signals and generate the correct and appropriate output signals to the motors, and to monitor the batteries. The microcontroller will also have to read values from the embedded system and determine appropriate control signals for the automatic yaw control. Lastly the software will need to be able to handle different states. For example, an on state when not much power is consumed but information is relayed that this system is working. Another state would be an operating state for when the sub is actually in use for the competition/testing. -Image processing software- This is where outside technical support from staff and other resources will help. The goal is to have the webcams image digitized and able to be analyzed in real time. The embedded system will not need to communicate with the microcontroller, only provide information constantly that the microcontroller can grab when it needs to. The only information the microcontroller may need to relay to the embedded system is whether to turn on/off based on the state. Below is a basic block diagram of the hardware layout:

6 Page 6/6 Once more information is obtained through research, a software flow diagram can be completed. This will be available on the next revision of this document. Below is a rough timeline of how this project will be completed: