Electromechanical Systems “Robotic Sorting System” Brent GuyJonathan Penney

Objectives Design a robotic sorting system Construct a routine to locate test tubes Ignores locations if shelf is empty Transport them from storage shelf to desired location

Design Specifications Robotic arm has 2 major limitations: Rotational limits Height constraints Size of shelf compartments Weight of test sample

Design Evolution Robotic arm with RGB sensor 9 compartment shelf design Puts samples on shelf Robotic arm with IR Sensor 3 compartment shelf design Takes samples from shelf

Hardware PIC Microcontroller 40-pin 16F877 embedded chip Provides analog to digital conversion Sends pulse waves to control servomotors

Hardware Servomotor Pulse-proportional servos move the links 180 degree range of motion Positions are based on incoming pulses units = 2.50 mS pulse (1 unit = 0.09 degrees)

Hardware SSC-32 Servo Controller Integrated circuit board that controls servos Servos plug into respective channels Reads converted digital inputs from PIC

Hardware MAX232 Converter Adjusts voltage of signals so communication can take place between PIC and SSC-32 SSC-32: -10 V for logic one, +10 V for zero PIC: +5 V for logic one, 0 V for zero

Hardware IR Proximity Sensor Panasonic sensor with 2 LEDs 4 – 26” range Sensitivity adjusted by potentiometers Information digitally sent to PIC

Software RIOS Allows user to configure servos Define positional limits of servos TTY Provides direct serial communication Allows for quick alterations * Final code produced in C

RIOS Screenshot

Programming a Servomotor Format: # P T - E.g. #0 P1000 T3000 Moves motor 0 to position 1000 in 3 seconds

Pseudo Code Set Initial Position Scan A –If object present, grip and drop –If not, continue to B Scan B –If object present, grip and drop –If not, continue to B Scan C –If object present, grip and drop –If not, Set Initial Position

Robot Demonstration

Difficulties Missing link parts Faulty servomotors Short wires required splicing Friction of base plate (removed 3 spokes) Power source

Recommendations Future Use Keep robot within suitable range (cannot move shelf without re-programming) Infrared sensor has trouble detecting transparent tubes Improvements RGB sensor Add movement for transportation Wheels Track

Conclusion Assembled Robot Programmed IR Sensor Shelf Construction Resulting in a functional robot that detects and transports test tubes for the biomedical industry