Toxic-free Coating, On the Go
Cadmium is widely used and a proven corrosion
protection coating on high-strength steels of military
and commercial aircraft. However, the metal is both
carcinogenic and toxic, and pressure is mounting to
use electroplated aluminum coatings instead. Unfortunately, the expense involved with existing electroplating solutions has hindered widespread adoption.
Fortunately, the recent development of a new class
of ionic liquid electrolytes has allowed the development of the Portable Aluminum Deposition System
(PADS) by Oak Ridge National Laboratory and
United Technologies Research Center. The breakthrough liquid formulation was
achieved, in part, by the use of hydrophobic neutral ligands, which considerably
increased the air stability of the plating electrolytes. Conventional aluminum electrodeposition must be performed in a water- and air-free environment, but PADS
reduces the air and water sensitivity issue by either making use of a portable electrolyte chamber or trapping the electrolyte inside a flexible gel membrane. In addition to providing the necessary coating protection, PADS offers flexibility to coat
substrate configurations traditionally impossible to coat and can repair corroded
surfaces in the open. Finally, aluminum electroplating eliminates toxic air emissions.
◗ Oak Ridge National Laboratory, www.ornl.gov
Friction-beating Engine Coating
Efforts to reduce carbon dioxide emissions will factor
heavily into engine development by OEMs, and this
will be accomplished in large part from the reduction
of internal friction. Daimler AG has made a significant
advance in this area with the introduction of NANO
SLIDE, an innovative coating for cylinder running surfaces of combustion engines to reduce CO2 emissions,
which allows for the use of lighter crankshafts and
reduces friction losses in the piston assembly. A new
twin wire arc spraying (TWAS) process was invented to
coat cylinder running surfaces with coating layers just
0.1 mm thick. Two consumable steel wires are fed into
a rotating torch, where an electric arc melts wire within
nitrogen, accelerating liquid metal directly to the cylinder wall. These droplets solidify into a nanocrystalline
lamellar layer, which is then honed. The finished surface reduces friction by 50%, retaining open pores for oil retention. The new coating
displaces heavy cast iron liners in current aluminum crankcases, bringing about a
carbon dioxide reduction of 3% for a single engine.
◗ Daimler AG, www.daimler.com
Precision Optics in One Step
Highly precise optics usually start with a rough-cut slab of
glass that’s painstakingly transformed to a polished, smooth
surface that’s flat to less than one wavelength of visible light.
This means a height variation of only a few hundred nano-
meters over a surface that measures centimeters in size. The
many steps involved in this process have been refined over
time, but, until now, the final full aperture polishing step has
consumed the most time of any step. Lawrence Livermore
National Laboratory scientists have developed a new pol-
ishing system capable of finishing flat and spherical glass
optics in a single iteration, regardless of the workpieces’ ini-
tial shape. Convergent Polishing: Rapid, Simple, Low Cost
Finishing of High Quality Glass Optics is able to “converge”
several steps because factors contributing to non-uniform
spatial material removal on the workpiece have been elimi-
nated and the creation of rogue particles within the polisher
system have been removed. This eliminates scratching and
low roughness surfaces. The polisher doesn’t use real-time
feedback, diagnostics or computer control to change polish-
ing parameters, which aids in the robustness and reliability of
the polishing process.
◗ Lawrence Livermore National Laboratory
Encoder-free Servo Motors
Industrial conveying and handling machines typically use
expensive permanent magnet synchronous drives (“servo”) or
cheaper induction motors equipped with brakes and clutches.
Induction motors, because of their design, suffer from efficiency
losses. Servo drives, meanwhile, are seen as less durable
because they are equipped with sensitive
encoders and extra wiring.
Engineers at Mitsubishi Electric Corp.
have eliminated the worst features of
both designs with the Sensor-less Servo
Drive Unit FR-E700EX Series and Sensor-
less Motor MM-GKR, which controls speed or position without the need for an
encoder. Unlike conventional servo motors, the FR-E700EX Series uses a sensor-free
vector control method, called a “virtual motor model”, for its control algorithm. The
model, or “observer”, is programmed into the drive unit and estimates motor flux
with the algorithm. Referring to the flux, the observer arranges vector control. With
input of voltage and current information on the motor, the observer calculates inner
parameters of the motor like flux, and estimates the speed and position of the rotor.
This approach doesn’t require detection capabilities of typically encoder-equipped
servos, allowing Mitsubishi to reduce motor complexity.
◗ Mitsubishi Electric Corp., www.mitsubishielectric.com
Automated assembly systems require organized, aligned parts. In most factories, unorganized parts are usually sorted and positioned by manual labor.
This task must keep pace with assembly, and is tedious and stressful. Parts
tools to automate “bin-picking” have previously been custom-designed for
each part. Machine vision has also been introduced, but it has been limited to
parts with simple shapes.
Mitsubishi Electric Corp.’s MELFA-3D Vision system for industrial
robot arms completely automates this bin-picking task. A projector creates
multiple slit patterns that are projected on the piled parts, which are captured with the camera. A depth map is reconstructed by using the captured
images and a structured-light decoding algorithm. Industrial parts generally
have no textures which creates challenges for 3-D reconstruction systems
using only cameras. MELFA-3D Vision can perceive and organize industrial
parts, because the slit patterns introduce artificial textures on the parts.
By comparing the part with a 3-D CAD model, the position is established.
To allow the robot arm to grasp it and position it correctly, a model matching method uses simple features and aggregates evidence in a voting framework. For complex parts, the system can task one robot arm to pick the part
from the bin and another to position it for assembly.
◗ Mitsubishi Electric Corp., www.mitsubishielectric.com