Innovation and a deep technical fiber optics know-how allows Micronor to tackle challenging tasks for position measuring solutions that will work reliably in hostile environments. Micronor has also partnered with numerous companies solving and implementing measurement solutions for nuclear research, medical MRI applications and mining.
Here we present our capabilities, the unique blend of engineering talent, fiber optics, electronics, optical, mechanical, software and project management plus in-house manufacturing. It is rare that one can find that mix of talent and capability in one place. Micronor has a 100% success rate in accomplishing projects on time and on budget.
Many of our products have sprouted from custom solutions because it is the customer who bring us the right ideas and what is required in the field. We affectionately call them TD’s, short for Technical Descriptions, the starting documents we develop to describe the customer’s requirements and configuration of the solution.
We have a list of 166 individual custom Fiber Optic Sensors projects. Here are just a few of those special solutions:
FREY AG – Fiber Optic Rotary Encoder Withstands Lightning Strikes
LAS VEGAS HIGH ROLLER – World’s Tallest Observation Wheel
PHILIPS RESEARCH – MRI Safe Encoder Enables Multi-Modal Heart Phantom
SENIOR SCIENTIFIC – Fiber Optic Linear Encoders Guide Superparamagnetic SQUID Sensor
POLYMER ROBOTICS – Fiber Optic Linear Encoders Guide MRI-Guided Biopsy Robot
Fiber Optic Rotary Encoder Withstands Lightning Strikes
In situations where human travel is necessary but where the geography is too steep or treacherous, aerial tramways often are used as a convenient alternative. Ski resorts, mountaineering centers, mining, logging, even archeological sites and cities with a diverse geography have tapped tramways as a method of transportation.
Aerial tramways can carry anywhere from a few to over 100 people. Lately the systems are also being seen as viable alternatives in overpopulated cities where geography or the urban landscape prohibits conventional transportation networks such as additional roads, subway lines, or trains. Aerial tramways are also used as an escape route at launch sites; pads 39A and 39B at Cape Canaveral are fitted with such systems.
The aerial trams offer a mix of harsh environments, from the outdoor encoder installations with direct exposure to weather and lightning, to the noisy electrical environment of the indoor motor, drive and control system. Critical requirements included:
- Immune to Lightning
- Fully Water Sealed
- Heavy Duty Construction to withstand handling in a heavy construction environment
- Output Signals are adaptable to each individual installation
Electrical noise is an ever present issue with conventional electronics-based incremental encoders, typically picked up along the long power/signal run from the encoder to A/B electrical quadrature inputs of the control system. This distance can sometimes run 100s to 1000s of feet. Electrical noise can add false pulses to the encoder’s output which would periodically defeat the fail-safe synchronization of the drive control system. A fiber optic sensor solution offering immunity to EMI and lightning inherently solves this problem.
When FREY AG (Stans, Switzerland) began constructing new aerial tramway systems, it turned to Micronor’s fiber optic MR316 ZapFree® ruggedized high resolution shaft rotary encoder to be part of the tramway’s positioning and cable systems. Aerial tramways differ from gondola lifts, which have smaller cabins, carry lighter loads, have several “cars,” and rely on a circulating looped cable. A reciprocal aerial tramway is composed of one or two fixed track cables, a loop of cable called a haulage rope, and two passenger cabins (some have only one).
The fixed cables provide support for the cabins. The haulage rope is usually driven by an electric motor, and, being connected to the cabins, moves them along the span of the tramway. The entire system uses a “jig-back” system, where the weight of the down coming cabin helps to pull the other cabin upwards. The MR316 passive fiber optic rotary encoder is used by FREY AG as part of the aerial tramway’s complex safety system, and is immune to lightning and other atmospheric conditions that could potentially disrupt function. The encoder has no integral electronics whatsoever as all Micronor fiber optic sensors. Specifically, the encoder is used to determine both the position of the cabins on the system as well as sense any potential slippage of the cable.
The safety-relevant monitoring systems, which in previous systems had been implemented in electronic boards and relay technology, are today implemented in programmable safety control systems Previous installations required an encoder, a pulse conditioner for Lightning Protection a frequency divider and a scalable frequency to voltage converter. The MICRONOR MR310 controller combines all the above function within on unit. Lightning protection is inherent to the fiber optic sensor and the frequency divider and scalable voltage output were already standard to the MR320 controller unit. As part of the installation package, Micronor provides ZAPPY™, a PC software program, which field technicians use to set the appropriate parameters for the given installation.
While Micronor designed the MR326 for environments where hazards to encoder function are obvious such as in heavy industry or EMI/RFI environments, FREY systems must also be immune to environmental factors such as corrosion, that are more surreptitious and long term. The company’s aerial tramways run in a wide range of geographical environments, from the moisture-laden conditions of the Colombian cloud forests, to the thin, cold air of the Swiss Alps, to the dry, hot air of Saudi Arabia’s western mountains, to the saline environment of South Africa’s coastal ranges. Each region presents a unique set of conditions for an encoder function that is exposed to the elements 24 hours a day and year-round. Several tramways also run in urban settings, whose man-made microenvironments present yet another set of conditions pertaining to operation. FREY does not restrict its use of the encoder to aerial tramways; the unit is also being used in the company’s inclined railway systems.
FREY AG aerial tramway installations are situated throughout the world. In the United States, Micronor had the unique opportunity to directly participate in one of those projects, the start-up of the $57-million Portland (Oregon, USA) Aerial Tram, which commenced operations in December 2006. The project was a joint venture between the City of Portland and Oregon Health Sciences University. The university needed a cohesive transportation solution to connect both upper and lower campus sites and the city saw the project as a tourist destination and means to lessen automobile traffic.
The 3,300-foot tram system ferries passengers (79 per cabin) in three minutes from downtown Portland’s South Waterfront District to the summit of Marquam Hill. The tram has succeeded as a popular tourist attraction, offering incredible views of the cityscape, the Columbia and Williamette Rivers which flow thorugh the city, the surrounding forests, and snow-capped Mt Hood in the distance. A symbol of success, the tram carried its one millionth passenger on October 17, 2007 and celebrated its ten millionth rider on January 8, 2014.
Micronor Part Numbers:
- MR316-C12T00 (EC-TD5027) Fiber Optic Incremental Encoder
- MR310 (EC-TD5245) Controller
- The original MR310 series fiber optic encoder system is now succeeded by the MR320 series, launched in 2011.
3300 Linear Travel of Portland Aerial Tram in feet
2007 Tram began operation in December 2007
256 PPR, Resolution of encoders used
3 MR316 encoders used by tram system
LAS VEGAS HIGH ROLLER
World’s Tallest Observation Wheel
At 550 feet high, the High Roller soars over the Las Vegas skyline and reins as the world’s tallest (Ferris) observation wheel, eclipsing both the London Eye (443’) and Singapore Flyer (541’). What an amazing ride experience it offers! The wheel takes 30 minutes to complete one full revolution and features 28 glass-enclosed cabins offering unobstructed 360-degree views of the famed resort city. With a total capacity of 1,120 passengers, each spherical cabin offers an expansive 225 square-feet of space which can either accommodate up to 40 traditional tourists or can be rented out for the ultimate bachelor, bachelorette or wedding party. Only in Las Vegas…
As an outdoor transportation system, the High Roller shares the same critical requirements as the Cable Cars discussed in the previous section:
- Immune to EMI, RFI and ground loops
- Immune to lightning
- Weatherproof and rugged for outdoor use
- High reliability for passenger safety and 24/7 operation
- Adaptable to measuring wheel application
The High Roller project was announced in August 2011 as the centerpiece of Caesar’s Entertainment Corporation’s $550 million “The LINQ Hotel and Casino”. Micronor worked with prime contractor Schwager Davis Inc. who was responsible for all of the mechanization equipment for the High Roller. At the engineering level, Heywood Engineering’s Lance Heywood selected the Micronor fiber optic encoders for drive feedback based on his experience with Doppelmayr/Frey aerial trams.
Schwager Davis developed the hydraulic system which provides the propulsion and normal breaking force for the system in normal use to rotate the wheel. There are a total of eight (8) Drive Units, each of which has four (4) large tires that provide the traction force to rotate the wheel. One full revolution of the wheel takes 30 minutes. The drive system is capable of rotating the wheel in both directions and has a total of 1000 HP.
The MR326 encoder was adapted with a friction wheel, by riding the rim of the High Roller just like the traction tires of the motor drives. A modified version of the Micronor MRAD spring-loaded measuring wheel arm was designed to accommodate the MR326 encoder and special Micronor 0.5-meter (1.64 feet) tufted rubber-coated wheel. For redundancy, each of these measuring wheel encoder systems is mounted on the east and west sides of the rim, synchronizing the rotation of the High Roller.
With a diameter of 520 feet, how many encoder pulses correspond to one complete revolution? The circumference (π*d) is 1633.62 feet. Divide by the measuring wheel circumference comes to 996.11 revolutions of the encoder. With an encoder resolution of 256ppr, that calculates to 255,005 pulses per revolution of the High Roller! Position resolution of the gigantic wheel is better than 2mm (0.1”)
The High Roller offered its first rides on March 31, 2014. In its first full year of operation (2015), the High Roller averaged 5,000 passengers per day corresponding to just under 2,000,000 passengers per year – serviced reliably by Micronor fiber optic encoders.
- MR326-C12C1R5 Encoder
- MR320 Controller
- 9350.02.093 Measuring Wheel Arm
- 9350.02.095 Tufted Rubber Coated Wheel
550 At 550 feet, the High Roller is the world’s tallest observation wheel
30 30 minutes for one revolution of the High Wheel
256 Resolution in pulses per revolution (ppr) of the MR326-C12C1R5 encoders used
2 Two MR326 rotary encoders are used for feedback in the High Roller drive control system
2 Can resolve gondola position within 2mm
MRI Safe Encoder Enables Multi-Modal Heart Phantom
Phillips Research (Briarcliff Manor, NY) engineers a variety of anatomically correct phantom human organs for the purpose of testing and calibrating MRI machines and their sophisticated software algorithms. Phantom organs are a more practical approach then using animals or cadavers and are also more repeatable for the purpose of calibrating the machines.
These organs are typically “powered” by pneumatics where the variation of air pressure provides the kinetic energy to the actuator for organ movement.
A challenge came up when a phantom heart had to be constructed. A heart consists of several muscles and the ventricles movement must be accurately synchronized. A position feedback with sufficient accuracy is required because the phantom heart must accurately mimic the biomedical properties of flex, compress, stretch and twist in an anatomically correctly fashion. All this must function within the MRI machine thus the feedback sensor must be immune to the high magnetic fields as well as the high RF fields that are generated by the MRI process. A further key requirement is that the sensor must be “transparent” to the MRI imaging process, meaning that the sensor may not interfere with the image acquisition and thus cannot have any ferro-magnetic properties or any conductive properties whatsoever.
The phantom organs are typically operated in a saline solution to mimic the real-life environment of the human body. Therefore, the sensors must be resistant to moisture and water sealed because they operate in a submerged environment.
The customer selected the MICRONOR MR328 MRI-compatible incremental encoder with 360ppr resolution. This encoder is built from all plastic materials such as polycarbonate (PC) and polyoxymethylene (POM); the precision ball bearings are ceramic material.
This same fiber optic encoder has been used in numerous other MRI applications where the magnetic field immunity was verified within the actual environment. Further the “transparency” to the imaging process was first verified by Marquette University:
Mehta et al, A novel technique for examining human brain activity associated with pedaling using fMRI, Journal of Neuroscience Methods, May 2009
The customers engineering personnel successfully implemented the Micronor encoders taking full advantage of the benefits of the fiber optics cables which lead the encoder signals to the outside of the MRI room to the controller unit. The phantom heart uses three encoders and requires three fiber optic links to be connected to the MR320 controllers. The controllers are linked with a first fiber optic segment leading into the MRI room where the encoder pigtails are joined using ST connectors. Micronor built the encoders having a10m long pigtail, thus avoiding any metallic parts within and near the MRI room.
The position of the phantom heart muscles are tracked by each controller unit (MR310) and are scaled to the built-in analog voltage output. The voltage output is fed into the servo controller which in turn controls the pneumatic actuators.
Fiber optic’s inherent immunity to EMI/RFI, magnetic fields and radiation has proven to be an enabler in fabricating a human phantom heart. MICRONOR’s ability to engineer kinetic sensors using only photons opens up the possibilities for new technologies, new products which allow for new and more efficient treatment methods within the realm of MRI.
60-100 Average normal resting heart rate for children (10 years and older) and adults
40-60 Average normal resting heart rate of a well-trained athlete
3 Number of encoders required for multimodal phantom heart
3 Three MRI safe, non-metallic encoders are offered by Micronor – MR303 Linear Encoder, MR328 Rotary Encoder, and MR338 Absolute Position Sensor
Micronor Products Used:
- EC-TD5253, Special waterproof version of MR318 MRI Safe Rotary Encoder, Qty 3
- MR310, Controller, Qty 3
- For new applications, use the MR328 Encoder and MR320 Controller
Fiber Optic Linear Encoders Guide Superparamagnetic SQUID Sensor
Senior Scientific LLC (Albuquerque, NM) is at the crossroads of biotechnology and nanotechnology. The company’s novel bioimaging and nanomagnetic detection systems have been developed specifically to detect cancer and other diseases earlier and with higher specificity than is currently possible. Tumor detection is accomplished by injecting a low dose of biologically-targeted nanoparticles (NPs), applying a brief magnetic pulse, and then detecting the resulting signal with an ultra-sensitive superconducting quantum interference device (SQUID). An advantage of superparamagnetic relaxometry (SPMR) compared to some imaging-based technologies is that it does not expose patients to potentially harmful ionizing radiation (e.g. x-rays) or radionuclides (e.g. PET) and is safe for human use.
Based on measurements of live cells of breast, ovarian, prostrate and leukemia cancers, they have been able to detect down to 10,000 cancer cells using the first generation MRX™ system. In comparison, transvaginal ultrasound (TUV) requires at least one billion ovarian cancer cells and breast x-ray mammography requires more than 100 million cells to detect the presence of breast cancer. The inherent sensitivity of SPMR holds great promise for enabling earlier cancer detection and lower medical costs.
The second generation Senior Scientific MRX™ instrument is designed to support both in vivo (live cells in live animal tissue) and in vitro (test tube or cultures) testing to further validate SPMR technology before moving to first in-human testing. In operation, a sample is placed on the specimen platform that has 3 DOF (degrees of freedom) with up to ±4 cm movement in the X and Y axes, and 0-20mm in Zs.
After injection and dispersal of the NPs, a small magnetizing field (50 Gauss) is applied for 0.75 seconds. Once the magnetic field is turned off, NP magnetic decay is measured (over 0.1 to 2 seconds) by the SQUID detector array. Additional measurements can be taken at different X and Y positions to form a topographic map of the magnetic dipoles, thereby identifying both size and location of tumors. The linear motion in the X and Y axes is driven by non-metallic, pneumatic actuator system but lacks complementary linear position feedback.
The MRX™ Sample Positioning System (SPS) required linear position sensors meeting these requirements:
- Entirely non-metallic (since the SPS will be within the magnetized field)
- 1mm resolution
- Immune to magnetic fields
- Invisible to magnetic fields (large and small)
- Not affect ultra-low level SQUID detection
To monitor absolute linear position, pre-production prototypes of the MR303 MRI safe linear encoder and MR302-1 DIN rail mount controller were proposed and used. The first MRX™ unit assembled with the MR303 and MR302-1 components operated successfully and production parts were used thereafter to build additional instruments.
The photo shows one axis of the SPS motion system incorporating the pneumatic actuator and MR303 Linear Encoder. Each stage moves along a fixed encoder film strip. The linear sensor is connected via duplex fiber optic cable to the remote MR302-1 Controller which outputs A/B quadrature pulses for position tracking by the MRX™ control system.
Products Used Per System:
- MR303-B400C05 MRI Safe Linear Encoder, Qty 2
- MR302-1 DIN Rail Mount Controller, Qty 2
- EC-TD5334 series Encoder Film Strip, Qty 2
50 Magnetic field strength in Gauss
20 Samples move up to 20cm on Z axis
4 Samples move up to ±4 cm on X and Y axes
2 MRX™ Sample Position System features 2-axis positioning
Fiber Optic Linear Encoders Guide MRI-Guided Biopsy Robot
Prostate cancer is the second most cancer related cause of death in men. PSA blood screening and Digital Rectal exams are the typical method for initially detecting possible presence of prostate cancer. A positive exam result would then lead to a biopsy and/or MRI imaging for verification. The increasing cost of cancer treatment has opened up creative opportunities for reliable methods for early detection.
Current prostate biopsy such as transrectal ultrasound guidance (TRUS) use sound waves to make an image of the prostrate. However, TRUS can’t tell the difference between normal tissue and cancer so the doctor guides himself to the prostrate, inserts a need through the wall of the rectum, and takes a biopsy sample. He repeats this process several times to assure that every area of the prostate has been sampled but areas can be missed. Also TRUS biopsy has a small but significant risk of serious infection since the rectal wall cannot be sterilized.
MR Guided Biopsy allows for very precise manual placement of the biopsy needle under a direct guidance of MRI. Polymer Robotics has taken the approach to automate the prostrate biopsy process by developing a transperineal MRI-guided Biopsy Robot, combining the low risk of infection by entering through the perineum (body between scrotum and anus) and the high resolution and accuracy of real-time MRI guidance.
The Polymer Robotics Falcon™ is the world’s first transperineal MRI-guide targeting system for prostate cancer. The Falcon requires 5 degrees of freedom (DOF) which requires high precision, non-metallic feedback sensors that can operate within the extreme magnetic field environment of an MRI bore.
Summary of requirements:
- Up to 16 inches of linear travel
- 0.1mm resolution
- Durability and repeatability over 200,000 cycles
- Absolute position after start-up
- Withstand MRI-generated as well as sound-induced vibration
When approached by Polymer Robotics in early 2014, Micronor proposed to utilize an incremental, linear sensor concept which was currently in development for a welding robot. Based on the proven and patented 2-phase/2-wavelength optical encoder system, a new miniature “read head” was designed. This read head consists of a ceramic subcarrier for the high precision optical components and the film guide molded from Acetal plastic material. This new optical read head is small enough to fit into very tight areas.
The success of the prototype led to the final design of the MR303 MRI Safe Linear Encoder and the MR302-2 OEM Controller. For 5 axis DOF, the customer required 4 sets of sensors and controllers for Falcon™ proof-of-concept. The first set was delivered in May 2014 with machined plastic bodies. Mold tools were subsequently completed and first production parts were later run without problems. Additional Falcon™ systems have been assembled for Phase II and subsequent human testing.
Environmental testing of the linear encoder followed and met all requirements. An active durability test of the sensor/film strip combination showed no performance degradation at initial test run of 250,000 cycles. Subsequent testing has verified operational durability beyond 500,000 cycles under simulated MRI-induced sound vibration.
The MR303, the world’s first MRI safe fiber optic linear encoder, was commercially released in June 2015.
Because of the proprietary nature of medical devices, internal details of the Falcon™ robot are not available but the MR303 position feedback has met expectations. An internal photograph shows two of the MR303 sensors and portions of the MRI compatible pneumatic drive system.
Products Used (per system):
- MR303-B400C1R5 MRI Safe Linear Encoder, Qty 4
- MR302-0 OEM Controller, Qty 4
- EC-TD5334-XXX series Encoder Film Strips, Qty 4