Seis Piernas The Step Climber

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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

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The Final Verdict in 10 mins

• Initial Expectations
• Changes made
• Capabilities and Behaviors
• Sensors
• Learning
• Conclusions

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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

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Initial Expectations

• Self calibrating
• Too much flexibility
• Double Tripod Gait
• Not enough power in the servos

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Changes made

• Removed bump switched below the legs for
  calibration
• Redesigned legs slightly
• Settled for a less efficient gait

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The Robot
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The Robot
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The Robot
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The Robot
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The Legs
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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

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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

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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

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Learning

• Servos are expensive
• Dont bolt everything down until close to demo
  day
• Soldering irons cause burns
• Dont trust data sheets
• Stepping on your robot will kill it
• No system is truly rigid
• Robots are very moody

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Conclusions

• The best learning experience ever
• Writing code to check every module really helps
  (USART is Gods 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

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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

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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

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Seis Piernas
Questions ?
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Thank You
The End