Motors in Space
<p style="text-align: center;"><img title="1603343401773281.jpg" alt="6.jpg" src="/ueditor/php/upload/image/20201022/1603343401773281.jpg"/></p><p>Components like motors, bearings and drives
are subject to harsh environments on Earth,
but they must be at the top of their game to
enjoy space travel. Recent applications from Maxon
Motors (Return to Mars) and the University of Michigan (Robotic Legs) illustrate the incredible requirements it takes to
handle applications in space and how these components
can be utilized here on Earth.</p><p><br/></p><p>Return to Mars
NASA¡¯s Jet Propulsion Laboratory (JPL) asked Maxon to produce 10 drives for its latest Mars rover, Perseverance. For
the first time, NASA is using brushless DC motors, including: nine EC 32 flat and one EC 20 flat in combination with
a GP 22 UP planetary gearhead. Working closely with JPL
specialists, Maxon engineers developed the drives over several years and tested them thoroughly to achieve the highest
standards of quality.
¡°We¡¯ve learned a lot from this exciting project,¡± says Robin
Phillips, head of the Maxon SpaceLab. ¡°We now have very
broad expertise in space applications and have established
quality assurance processes that meet the expectations of
the industry. Customers from other industries such as the
medical sector, where requirements are often similar, can
also benefit from this know-how.¡±
Space missions place the highest demands on drive systems. This includes vibrations during the rocket launch, vacuum during the journey, impacts on landing, and the harsh
conditions on the surface of Mars, where temperatures fluctuate between ¨C125 and +20 degrees Celsius and dust penetrates everywhere. A drone helicopter called Ingenuity is
attached to the bottom of the rover and includes six Maxon
brushed DCX motors with a diameter of 10 millimeters controlling the tilt of the rotor blades and the
direction of flight. The Perseverance rover
is expected to land on Mars on February
18, 2021. Editor¡¯s Note: Learn more on
page 20.</p><p><br/></p><p>Improving Robotic Legs
In a recent article by the communications
department at the University of Michigan, scientists created a robotic leg prototype that offers a more natural gait and
is more energy efficient than previous designs. The key is the use of new small and
powerful motors, originally designed for
a robotic arm on the International Space
Station. The streamlined design offers a
free-swinging knee and regenerative braking, which charges the battery with energy
captured when the foot hits the ground.</p><p><br/></p><p>This feature enables the leg to more than double a typical
prosthetic user¡¯s walking needs with one charge per day.
Motors in robotic legs need to fit into the space that an ordinary limb would take up. In the past, this has meant using
small motors that spin quickly, and then using a series of
gears to convert the fast spin into a more powerful force.
The problem is that the gears are noisy, inefficient, add
weight and make it harder for the joints to swing. Robert
Gregg, an associate professor of electrical and computer engineering at the University of Michigan and a member of the
U-M Robotics Institute, and his group surmounted this by
incorporating two of those stronger space station motors,
one powering the knee and the other powering the ankle.
There are many benefits to using fewer gears. In addition to
enabling the free-swinging knee, removing gears brought the
noise level down from the scale of a vacuum cleaner to a refrigerator. Also, the regenerative braking absorbs some of the
shock when the prosthetic foot hits the ground. The team¡¯s
next step is to improve the control algorithms that can help
the leg automatically adjust to different terrain, changes in
pace and transitions between different types of activity.
Learn more here: (news.umich.edu/space-station-motorsmake-a-robotic-prosthetic-leg-more-comfortable-extendbattery-life/)</p>
22 Oct,2020