In mid 2008, a potentially achievable plan was formulated on how ERO
could possibly meet her prime directive of "Get Daddy a Beer". Using
the race track we painted on the basement floor for the kids to ride
their bikes on, and the dorm-size refrigerator tucked under the
ping-pong table, ERO would do line following (track the line) around the
track while scanning for the refrigerator with a camera. Then she would
somehow drive to the refrigerator, open it, get a bottle of beer out,
store it somewhere on her 3rd level, get back to the race track, and
track the line back to Daddy. This would be implemented as a software
state machine as follows:
Step 1: Track the line, scan for fridge
Step 2: Drive to fridge
Step 3: Find handle
Step 4: Open fridge
Step 5: Re-approach for beer fetch
Step 6: Arm fetch beer
Step 7: Drive back to line
Step 8: Track the line, scan for Daddy
Step 9: Present beer to Daddy
Line Tracking
Date:
June 4, 2009
ERO Rev:
v3.5
A seemingly trivial task for most robots, you'd be surprised how
difficult this was to achieve with a 2.5" ground clearance
requirement!
On May 15, 2009, the construction of an array
of 7 infrared sensors that could do the job was completed. On June
4, 2009, the software that allowed ERO to track the line around
the basement track was completed.
Arm Fetching Beer (preliminary)
Date:
July 26, 2009
ERO Rev:
v3.5
OK, so the bottle is empty and I had to hand it to her...
it's progress!
Find Fridge
Milestone: ERO finds the fridge for the first time!
Date:
August 18, 2009
ERO Rev:
v3.5
The yellow piece of paper taped to the fridge helps the CMUcam vision
sensor to lock in on it
Open Fridge
Milestone: ERO opens the fridge for the first time!
Date:
August 25, 2009 (1st crude success)
September 4, 2009 (more repeatable and polished, and what
you see in this video)
ERO Rev:
v3.5
The video shows steps 1 - 5 of the 9-step state
machine for achieving the prime directive.
Opening the fridge takes 4 lbs. of force, which the arm
alone can not provide. The main drive motors actually do
most of the work, all the arm has to do is not
self-destruct.
Why are there now 3 colored rectangles taped to the fridge?
The turquoise square in the middle of the fridge is
used in Step 1: Track the line, scan for fridge
The yellow square above the turquoise square is
used in Step 2: Drive to fridge
The small red rectangle on the handle is used in Step 3:
Find handle
Get (empty) Beer
Milestone: ERO "Get me a Beer", complete sequence (sort of)!
Date:
October 16, 2009
ERO Rev:
v3.5
Caveats:
Empty beer bottle for now.
Still very un-repeatable. Step 6 is ~20% repeatable, entire
sequence is < 5% repeatable.
The video shows the complete 9 step sequence of the prime directive
from voice command to completion
From v3.5 to v3.7, ERO's arm was upgraded a few times...
The bicep joint is in torque overload initially. When the other
joints bring the beer in close enough, the torque requirement is
reduced, and the bicep can finally lift it.
After an 8 year hiatus, ERO has been resurrected. With no additional hardware
modifications, I was finally able to achieve results from the extensive arm
and vision upgrades of v3.6 and v3.7.
Arm Fetching Can of Beer from Fridge
Milestone: ERO fetches full can of beer, cleanly!
Date:
March 12, 2024
ERO Rev:
v3.8
Caveats:
She can only detect this exact kind of beer for now
The video shows steps 6.3 - 7 of the "Get me a Beer" sequence
Get Me A Beer (getting better...)
Date:
March 18, 2024
ERO Rev:
v3.8
Caveats:
Much more reliable than the v3.5 version, but still needs work
Here's one of the better v3.8 takes of "ERO Get Me A Beer", from
the end of step 1 until failing step 7. It's unfortunate that
she's tethered to a laptop for various reasons, but I assure you,
she's still fully autonomous!
Tried to insert a step to close the fridge, due to negative feedback
from v3.5 video, but it's harder than I thought.