How do you keep stable on choppy seas? Drinking a martini may calm your nerves – but this Martini will calm the waves.
According to Popular Science, a pioneer in subwoofer and LIDAR (Light Detection and Ranging) technology, has hacked airbag systems and built a self-stabilizing boat called the “Martini 1.5.”
Velodyne CEO David Hall used four Firestone truck airbags as actuators in a pneumatic system to create an elaborate suspension that keeps the deck stable. The airbags allow for shifts in the amount of weight on top of the deck, and also as housing for a set of 4 DC servo-motors that stabilize the deck in response to motion from the waves below, according to PopSci:
Steven Shonk, the Martini 1.5’s lead engineer and captain, says the heavy-duty technological know-how lies not so much in the mechanical system as in the software, which must track the position of the deck in space and send real-time instructions to compensate for wave action.
“Putting it all together and writing the software is challenging,” says Shonk. “It’s an active suspension that automatically adjusts for the waves – it’s not a passive system.”
The computer “brains” of the operation lie on deck – linear accelerometers and a 3-axis gyroscope send spatial information to an off-the-shelf Altera computer chip called a field-programmable gate array (FPGA). The FPGA sends instructions to a pair of motor controllers, each of which controls a direct current servo motor built onto the tops of the 4 airbag-actuators, which are affixed to the front and back of the deck. The motors are the workhorses, constantly and continuously driving lead screws through the airbags, lifting and lowering the deck via a set of legs onto pontoons. The pontoons bounce and roll in response to the action of the waves, but the continuous movements of the lead screws push up on the deck to prevent it from following the pontoons into the trough of a wave.
“It’s actively, and rapidly, and constantly making adjustments to keep the deck level,” says Shonk.
The complex system adjusts for the changes in pressure on the deck when people move themselves or cargo, shifting the distribution in weight aboard the vessel. A pump feeds into an accumulator and then the airbags – so if, for example, 4 crew members, weighing a total of 200 pounds, gather at one side to pull in some crab pots, the accumulator pumps a couple of pounds of pressure beneath them to keep the surface level.
Hall too the rig out for a test-ride in the choppy San Francisco Bay flanked by ferries and cargo ships – pushing the boat to a whopping 38 MPH through the chop. According to Popular Science, Shonk estimated that without the suspension system, he would need to pilot the craft through the moderately rough waters at about 12 MPH.
Check out part of the test video here:
(H/T: Popular Science)
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