October 27, 2015 Volume 11 Issue 40

Motion Control News & Products

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Small brush DC motors drive handheld biopsy system

When developing an automated, handheld system capable of harvesting multiple samples with a single insertion to reduce patient tissue trauma and sampling time, this medical device manufacturer turned to MICROMO for compact and high-efficiency FAULHABER® brush DC motors.
Read the full article.

Compact angle sensor for robotics and other applications

See the robotics video demonstrating ease of programming and robotics application of certain angle sensors from Novotechnik. Novotechnik’s Vert-X 1600 Series of angle sensors (shown here) features easy mounting in tight spaces with a 16 mm diameter body. The sensors measure 0 to 360° with linearity ≤ ±0.3%, 14-bit resolution and repeatability to 0.1°. A variety of analog and digital output options are available.
View the video.

Zero-backlash servo rotary indexing table

The Sankyo Automation RollerDrive Reducer is a precision gear reducer that uses a zero-backlash roller gear mechanism. The unit is constructed from an input shaft and a turret (output shaft) that is assembled with roller followers. The roller followers are preloaded against a screw-like input shaft to eliminate backlash. Sankyo servo indexing tables offer a constant lead cam with a servo motor drive for programmable motion and provide fast, highly accurate motion, with the added capability to move medium to heavy loads. The RU Series servo indexing table is available in 11 different sizes and varying ratios.
Click here to learn more.

Plug-in motor controller for fast integration

Nanotec has introduced a new controller specifically for integration into devices: the NP5 plug-in motor controller, which is suitable for both brushless DC motors and stepper motors. A PCI Express connector allows for fast and easy integration into a customer-specific board, offering a compact and affordable solution that reduces wiring effort, particularly for multi-axis applications. The NP5 controller can control motors with a rated current up to 6 A via FOC, Hall sensors, or sensorless control. In addition to position, speed, and torque control, operating modes with cyclical set value specification are also available for interpolated multi-axis operation. Nanotec offers the free Plug & Drive Studio software for parameterization and programming.
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Low-profile rotary air bearing stages achieve superior accuracy with virtually unlimited life

The new A-635/A-637 PIglide low-profile rotary air bearing stages from PI (Physik Instrumente) have no rolling or sliding elements and deliver frictionless, non-contact motion, resulting in negligible reversal error and better wobble eccentricity and velocity stability -- ideal prerequisites for high-end industrial applications such as inspection, metrology, calibration, and scanning, including cleanroom environments. Featuring 3-phase, low-cogging slotless torque motors with velocity to 500 rpm and optical encoders, these stages provide outstanding resolution, repeatability, and absolute accuracy.
Click here to learn more.
Watch PI’s Air Bearing Design & Manufacturing Operation Video.

Where would I get an exoskeleton joint actuator?

maxon motor is now offering a complete joint actuation unit consisting of a pancake brushless DC motor (EC90 flat) with inertia optimized rotor, internal high-resolution 4096 MILE Encoder, planetary gearhead with absolute encoder, and EPOS4 position controller with CAN and RS232 interface. Fitting the 17-bit SSI absolute encoder directly at the joint rotation to a degree will negate the effect of gearhead backlash, giving designers increased positioning accuracy. The unit will deliver 54 Nm of continuous torque and 120 Nm on a 20% duty cycle. The system can be operated on supplies between 10 VDC and 50 VDC, and the actuation speed is up to 22 rpm.
Learn more.

Programmable electric moving coil servo actuator

Introducing the 35-mm diameter CBL35C electric cylinder from SMAC. With its built-in controller, the CBL35C controls force, position, and velocity and features simple installation. Ideal for applications with limited space but requiring accurate control, the CBL35C provides significantly longer life, programmability, high speed, accuracy, and energy efficiency while remaining price-competitive. It also enables the direct replacement of existing pneumatic cylinders and retrofits without any machine modifications required.
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Zero downtime available for FANUC robots

The Robot LINKi Zero Down Time (ZDT) service is now available to all automotive and non-automotive manufacturers who purchase FANUC robots. Launched in 2015 in collaboration with Cisco, ZDT is a predictive analytic service that automatically monitors robot health status and upcoming maintenance requirements. It eliminates the need for manual analysis and tracking, avoiding unexpected breakdowns during production. Today, over 16,000 robots in the automotive industry are operating with ZDT, which is available for all FANUC R-30iB Plus robots as well as R-30iA and R-30iB robots with the latest software version.
Click here to learn more.

Selecting pneumatic or electric actuators

For some automation applications, it can be difficult to decide if a pneumatic or electric motor-driven actuator is best. Obviously, cost can be a big factor when choosing between the two, with pneumatic actuators typically costing less. So why should you pay more for an electric rodless actuator? Rollon says the answer boils down to higher levels of stiffness, as well as dynamic speed and motor control.
Read the full article.

Top 5 challenges of motion control design

As motion control solutions -- from angle encoders to direct drive motors -- become even more ubiquitous in industrial situations, engineers face evolving demands and opportunities. From lowering the cost of advanced technologies to improving functional safety in automated environments, here are the top five challenges and opportunities in today’s motion control design industry as seen by engineers from HEIDENHAIN.
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XY stage gives high resolution and repeatability

The XYR-03-01 Motorized Alignment Stage from Optimal Engineering Systems (OES) is a high-resolution, high-repeatability XY-Theta (3-axis) stage for applications such as angular glass cutting and grinding, wafer alignment, semiconductor handling, and laser cutting and drilling. The linear resolution of the X and Y axis is 5µ (non-micro-step) or 0.125µ (20 micro-steps per step motor driver in use), the repeatability is 1.5µ, and positional accuracy is 5µ. The 1-mm per-turn lead screws and preloaded V-groove and crossed roller bearings add to the high precision and stiffness of the XYR-03-01 alignment stage.
Click here to learn more.

Top-of-the-range high-resolution encoder

Requirements on encoders are becoming more and more demanding, particularly for positioning applications with precision constant-speed control, where increasingly compact housings need to accommodate an ever-greater number of electrical contacts. maxon motor solves this problem with its new ENX 16 RIO (Reflective, Interpolated, Optical) encoder. It is a mere 16 mm in size and offers a resolution up to 65,536 counts per turn, making it ideal for the precise position and velocity control of DC motors. With a 16-mm outer diameter and a 7-mm overall length, the housing is mechanically robust and protected from dust due to its injection-molded construction. The operating temperature range is -40 C to 100 C. It fits the new brushless EC-i 30 motors and the brushed DCX motors. The encoder can be combined and configured with matching drives online.
Click here to learn more.

High-traction robot goes underground

Recent developments in motion control and engineering make it possible to inspect and perform maintenance in compact sewers from the inside. The underground sewer robot is equipped with a swiveling camera and an air-powered milling machine driven by FAULHABER miniature DC motors from MICROMO.
Read the full article.

Tips for selecting linear actuators

Aaron Dietrich from Tolomatic runs through the main specifying considerations for electric actuators, citing their high performance, adaptability, low total cost of ownership, and easy integration. But what about accuracy and repeatability? Should you go with a rod-style actuator or a screw type? What kind of force should you expect if you are considering converting from hydraulic to electric actuation? Tolomatic also offers an extensive ebook to help with your decision-making if you need it.
Click here to learn more.

Cost-optimized BLDC motors for series production

With the DBL36, Nanotec now offers a brushless DC motor that is designed for large quantities. This motor is available in three lengths with a rated power of 7.5 W (size S), 18 W (size M), and 33 W (size L). These electronically commuted 3-phase motors are equipped with three Hall sensors that provide information on the rotor position. They are characterized by very high efficiency and, thanks to their precision ball bearings, smooth running characteristics. The rated speed is 4,800 rpm for sizes S and M and 4,500 rpm for size L; its rated voltage is 24 V. With a rated torque of 1.5 to 7 Ncm and a diameter of 36 mm, the DBL36 is an extremely economical solution for a wide range of applications. The winding can be adapted to other rated speeds and voltages in series production.
Click here to learn more.

MIT researchers say detour to the moon is the best route to Mars

By Jennifer Chu, MIT

[Illustration: Christine Daniloff/MIT]



Launching humans to Mars may not require a full tank of gas: A new MIT study suggests that a Martian mission may lighten its launch load considerably by refueling on the moon.

Previous studies have suggested that lunar soil and water ice in certain craters of the moon may be mined and converted to fuel. Assuming that such technologies are established at the time of a mission to Mars, the MIT group has found that taking a detour to the moon to refuel would reduce the mass of a mission upon launch by 68 percent.

The group developed a model to determine the best route to Mars, assuming the availability of resources and fuel-generating infrastructure on the moon. Based on their calculations, they determined the optimal route to Mars, in order to minimize the mass that would have to be launched from Earth -- often a major cost driver in space exploration missions.

They found the most mass-efficient path involves launching a crew from Earth with just enough fuel to get into orbit around the Earth. A fuel-producing plant on the surface of the moon would then launch tankers of fuel into space, where they would enter gravitational orbit. The tankers would eventually be picked up by the Mars-bound crew, which would then head to a nearby fueling station to gas up before ultimately heading to Mars.

Olivier de Weck, a professor of aeronautics and astronautics and of engineering systems at MIT, says the plan deviates from NASA's more direct "carry-along" route.

"This is completely against the established common wisdom of how to go to Mars, which is a straight shot to Mars, carry everything with you," de Weck says. "The idea of taking a detour into the lunar system ... it's very unintuitive. But from an optimal network and big-picture view, this could be very affordable in the long term, because you don't have to ship everything from Earth."

The results, which are based on the PhD thesis of Takuto Ishimatsu, now a postdoc at MIT, are published in the Journal of Spacecraft and Rockets.

A faraway strategy
In the past, space exploration programs have adopted two main strategies in supplying mission crews with resources: a carry-along approach, where all vehicles and resources travel with the crew at all times -- as on the Apollo missions to the moon -- and a "resupply strategy," in which resources are replenished regularly, such as by spaceflights to the International Space Station.

However, as humans explore beyond Earth's orbit, such strategies may not be sustainable, as de Weck and Ishimatsu write: "As budgets are constrained and destinations are far away from home, a well-planned logistics strategy becomes imperative."

The team proposes that missions to Mars and other distant destinations may benefit from a supply strategy that hinges on "in-situ resource utilization" -- the idea that resources such as fuel, and provisions such as water and oxygen, may be produced and collected along the route of space exploration. Materials produced in space would replace those that would otherwise be transported from Earth.

For example, water ice -- which could potentially be mined and processed into rocket fuel -- has been found on both Mars and the moon.

"There's a pretty high degree of confidence that these resources are available," de Weck says. "Assuming you can extract these resources, what do you do with it? Almost nobody has looked at that question."

Building a network in space
To see whether fuel resources and infrastructure in space would benefit manned missions to Mars, Ishimatsu developed a network flow model to explore various routes to Mars -- ranging from a direct carry-along flight to a series of refueling pit stops along the way. The objective of the model was to minimize the mass that would be launched from Earth, even when including the mass of a fuel-producing plant, and spares that would need to be pre-deployed.

The approach models the movement of cargo and commodities, such as fuel, in a supply chain network in space. Ishimatsu developed a new mathematical model that improves on a conventional model for routing vehicles. He adapted the model for the more complex scenario of long-term missions in space -- taking into account constraints specific to space travel.

The model assumes a future scenario in which fuel can be processed on, and transported from, the moon to rendezvous points in space. Likewise, the model assumes that fuel depots can be located at certain gravitationally bound locations in space, called Lagrange points. Given a mission objective, such as a set of weight restrictions, the model identifies the best route in the supply network, while also satisfying the constraints of basic physics.

Ishimatsu says the research demonstrates the importance of establishing a resource-producing infrastructure in space. He emphasizes that such infrastructure may not be necessary for a first trip to Mars. But a resource network in space would enable humans to make the journey repeatedly in a sustainable way.

"Our ultimate goal is to colonize Mars and to establish a permanent, self-sustainable human presence there," Ishimatsu says. "However, equally importantly, I believe that we need to 'pave a road' in space so that we can travel between planetary bodies in an affordable way."

"The optimization suggests that the moon could play a major role in getting us to Mars repeatedly and sustainably," de Weck adds. "People have hinted at that before, but we think this is the first definitive paper that shows mathematically why that's the right answer."

William Gerstenmaier, associate administrator for human exploration and operations at NASA, says understanding what resources may be available, both along the way to Mars and once there, is "essential to sustainable human presence beyond low-Earth orbit."

"The paper shows clearly that leveraging water and other valuable in-space resources will lower the cost for human exploration of the solar system," says Gerstenmaier, who was not involved in the research. "NASA had previously planned on using Mars resources to reduce propellant needs at Mars. This study, along with others, is showing the potential advantages of using lunar resources as well."

Source: MIT

Published October 2015

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