Automated Maze System Development Group 9 Tanvir Haque

Automated Maze System Development Group 9 Tanvir Haque Sidd Murthy Samar Shah Advisors: Dr. Herbert Y. Meltzer, Psychiatry Dr. Paul King, Biomedical Engineering

Introduction ¡ Microdialysis l l Method of measuring physiological activity during task Dr. Meltzer’s Lab uses it to study brain activity during memory tasks

Experimental Setup ¡ ¡ Rat hooked up to Microdialysis Rat placed in Maze, performs memory tasks Sample collected during maze run Sample Analyzed for content

Problems ¡ ¡ Dialysis tubes’ entanglement Rat’s recognition of overhead device l ¡ psychological repercussions Manual guiding of tubes cumbersome for researcher

Constraints ¡ ¡ ¡ Maze Dimensions Rat Size Rat Speed Rat Cognition Tube Length Dialysis Weight Depth: 18”

Primary Objective To develop a fully independent research module that facilitates the study of memory

System Description Translate Dialysis Machine Acquire Mouse Position Determine Change in Position

Position Acquisition Method Pros Cons Camera ¡ High Resolution ¡ Mounting Issues ¡ Real-Time ¡ Processing Sensor feedback Limitations ¡ Software intensive ¡$1, 355 ¡ Manageable data ¡ Low resolution ¡ Less processing ¡ Center of maze difficult to map ¡$1, 160

Image Processing Acquire Image Calibrate the Image Convert the 32 bit image to an 8 bit image Pattern Match to a Specified Image Filter Image 2: Remove Small Objects Filter Image 1: Remove Border Objects Translate pixel value into physical coordinates Output Physical coordinates in array form Determine the pixel at the center of the pattern

Lab. VIEW Software Code

Image Processing Unprocessed Image Processed Image

Lab. VIEW Screen Shot

Choosing a Microprocessor Motorola 68 HC 11 E ¡ One 8 -bit input ¡ Low cost ¡ On board A to D converter ¡ $200 NI PCI-7342 ¡ Four 8 -bit inputs ¡ More processing capabilities ¡ Software Compatibility with Lab. View ¡ $895

Processing the Information ¡ ¡ Continually Given one set of coordinates (X, Y) Compares the coordinates of (Xn-1, Yn-1) to (Xn, Yn), computes the difference, and rounds the significant digits Converts the difference into specified timed waveform for the driver Driver amplifies signal and controls motor speeds

Drive System ¡ Lead-screw Device l l l ¡ Easy to build Inefficient $1, 576. 72 Pulley/Belt System l l l Complicated System Efficient $6, 000

The Lead-Screw Device • Motor Driven • Rotational Energy converted to Linear Energy

Device Apparatus

Device Apparatus • Driven by dual motor system • Translation responds to mouse movements • Open Loop Feedback

Choosing a Motor ¡ Design Considerations: l l Speed of Mouse: 2 ft/s Torque needed to drive apparatus ¡ Torque needed to provide acceleration ¡ ¡ Stepper Motor or DC Motor?

Speed RPM = 25. 5 in/s / Lead*60 s/min Lead (in/rev). 125 RPM 11520 . 25 5760 . 5 2880 Target RPM Range 3000 -12000

Torque ¡ Driving Torque L = 2. 37 lbs P =. 5 in/rev ef=. 4 (for ACME) Tf = 53 m. Nm ¡ Acceleration Driving Torque I = 0. 001207 lb-in-s 2 α = 265 rad/s 2 T = 36 m. Nm Worst Case Scenario 25 in 2 ft/s Position ¡ -25 in Time

Stepper or DC? ¡ Stepper l l ¡ Torque < 3. 53 Nm RPM < 2000 DC l l High Torque High RPM

DC Motor ¡ ¡ 3000 RPM (using 0. 5 lead) 87 m. Nm Torque Powered by Driver Monitored by external Optical Encoder

Flow Chart Micro. Processor Calculate Δ(x, y) Image Motor Translation Driver

Budget Support Scaffolding $99. 70 Mechanical Arm $1576. 72 (including driver electronics) Microcontroller $895. 00 Labview/Imaging Software $1, 355. 00 Grand Total $3926. 42

Departmental Reconsiderations Budget limitations caused the psychiatry department to reconsider the value of their experimental setup. Thus, our design, though it was considered valuable by the department, was not approved.

Contingency plan Develop a model which represents fundamental principles of design ¡ Image acquisition system demonstration – Lab. VIEW software ¡ Mechanical arm system demonstration – Erector set ¡

Overall Status ¡ ¡ Developing Theoretical Model Next step: Final Report and Poster Board Month/ Tasks January February March April Breakdown of parts needed Researched parts and obtained quotes Offer proposal for parts Develop theoretical model Build theoretical model Work on Poster Board Work on Final Report

Conclusion Though no tangible design will be developed, a better understanding of image acquisition systems, microprocessing and linear actuators was obtained With the development of theoretical model, the perceived design was realized and used for its educational purposes