Seis Piernas – The Step Climber

Department of Electrical and Computer Engineering EEL 5666 Intelligent Machines Design Laboratory 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

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 Legs

Capabilities and Behaviors • Performs obstacle avoidance • Walks with the six leg gait/swim • Capable of climbing 3” steps • 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. • Very sensitive so not totally reliable • Built my own board and surface mounted the chip! • 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 • Break beams • Shaft encoders • Flex Sensors • Pyro detector • CMU Cam communication • Beacons • Practical Gearing • Line Following

Seis Piernas Questions ?

Thank You The End

Seis Piernas – The Step Climber