Seis Piernas – The Step Climber

by

Amit David Jayakaran

Date: 12-Dec-02

Instructor: Dr. A. A Arroyo

Dr. E. M. Schwartz

TAs: Jason Plew

Uriel Rodriguez

Department of Electrical and Computer EngineeringEEL 5666

Intelligent Machines Design Laboratory

The Final Verdict in 10 mins

• Initial Expectations

• Changes made

• Capabilities and Behaviors

• Sensors

• Learning

• Conclusions

Initial Expectations

• Capable of climbing 6” steps Length to width ratio Height of robot Servo power (rated far above capability) Servos not capable of putting out a uniform torque

at all angles Flexibility in the mechanical setup

Initial Expectations

• Self calibrating Too much flexibility

• Double Tripod Gait Not enough power in the servos

Changes made

• Removed bump switched below the legs for calibration

• Redesigned legs slightly

• Settled for a less efficient gait

The Robot

The Robot

The Robot

The Robot

The Legs

Capabilities and Behaviors

• Performs obstacle avoidance

• Walks with the six leg gait/swim

• Capable of climbing 3” stepso Able to know if it missed the step and will retry

before giving up

Sensors

• The IRs for obstacle detection• The IR for step detection• The accelerometer to check the inclination of the

robot with the horizontal.o Very sensitive so not totally reliableo Built my own board and surface mounted the chip!o Built a confidence system to improve reliability

• Dropped bump sensors due to difficulty of implementation

Learning• Practically everything was new to me

• Servos and PWM control

• 25 Amps is never enough

• IR and its application

• Smoke is not a good sign

• Microcontrollers (Interrupts/Input Capture/ADC)

• 10 hours of battery charge gives you only 20 minutes of quality time

Learning• Servos are expensive

• Don’t bolt everything down until close to demo day

• Soldering irons cause burns

• Don’t trust data sheets

• Stepping on your robot will kill it

• No system is truly rigid

• Robots are very moody

Conclusions

• The best learning experience ever

• Writing code to check every module really helps (USART is God’s gift)

• Although I spent more time working more on other peoples robots than my own I really enjoyed it

• Have written a lot of routines that will really help anyone who does a walker in the future with the Atmel

Conclusions

• I love debugging and since Murphy is our friend I really got a lot of hands-on, not just with my project but with others too.

• Over all satisfied with the output and performance of my project

Suggestions for future• Make students visit the lab more frequently so

that everyone gets a feel of what others are doing and learns from it

• Encourage more team activity. I did it this whole semester and have learned not just all that I needed for my robot but stuff like

o Break beamso Shaft encoderso Flex Sensors

o Pyro detectoro CMU Cam

communication

o Beaconso Practical Gearingo Line Following

Seis Piernas

Questions ?

Thank You

The End