Micronor MRI Rotary Encoder Wins 2010 Control Engineering Award
Newbury Park, California- Micronor's MR318 MRI-compatible Fiber Optic Rotary Encoder has won Control Engineering magazine's 2010 Engineer's Choice Award for Motion Control products. With a combined print and e-zine readership of nearly 90,000, CE readers voted for the best products in 29 different subcategories. The honor recognizes Micronor continued leadership in all-optical, 100%-passive fiber optic encoders for motion control and position sensing.
The MR318 Fiber Optic Rotary Encoder is the world's first and only commercially available, non-metallic rotary position sensor that can operate with complete "transparency" in extreme electromagnetic fields. The product concept grew out of requests from the magnetic resonance imaging (MRI) community for a non-metallic version of Micronor's existing fiber optic encoder products.
Prior to the MR318, engineers had no commercial solution for measuring continuous position within an MRI chamber. Motors or actuators could be hydraulic or pneumatic but no commercial, non-metallic position sensor existed. A homemade fiber optic proximity/limit switch was the best solution - but this was awkward to design, package and could only provide position information at discrete points. The advent of the MR318 enabled fully-functional motion control apparatus with closed-loop feedback.
The MR318's product development combined Micronor's proven passive fiber optic encoder technology (U.S. Patent 7,196,320) with challenging material engineering that flowed down to the smallest component. For interchangeability and compatibility with existing products, the MRI encoder would use the same industry-standard Size 58mm form factor (same as popular MR312 metallic encoder) and pair with the same MR310 interface module.
The MRI environment-specific material requirements represented the greatest challenges. Anything (patient or equipment) placed in the MRI chamber must be devoid of metallic or ferrous materials which might disrupt the MRI machine's electromagnetic field and operation. It became more that a part-for-part conversion of the existing MR312 encoder's design. Special attention had to be paid to the choice and machinability of materials chosen for the housing, shaft, bearings, encoder wheel and optical assembly. The optical fiber and optical components (filters and mirror) were the only original components that did not require redesign.
The MR318 rotary encoder has become an enabler for functional-MRI (fMRI) research and related medical applications. The device allows medical researchers and radiologists to develop MRI-compatible test and diagnostic apparatus where measuring position, angle or speed is required. It became possible to monitor the brain activity of stroke and other impaired patients while engaged in various locomotor activities (pedaling, lifting, limb movement, etc.). For example, monitoring brain activity at discrete pedal positions allows the researcher to observe how the brain and body adjusts to therapy as well as evaluate new rehabilitation techniques. The encoder also enables the development of more sophisticated MRI phantoms for machine calibration, teaching and training.
Non-medical applications - especially military and industrial - also exist for the MR318. The RF "transparency" of the encoder is ideal for designing embedded servo loop systems for equipment designed for EW (electronic warfare), DEW (directed energy weapons) and EMC (electromagnetic compatibility). There are test apparatus applications within anechoic chambers as well as electromagnetic-based industrial separation processes. As an example, the MR318 encoder provides X/Y position feedback for a prototype electromagnetic sensor array.
Micronor wishes to thank Marquette University's Biomedical Engineering graduate student, Jay Mehta and his advisor, Dr. Sheila Schindler-Ivens, who provided the first application - a pedaling device - for the prototype MRI encoder. The results of their research project were published in the Journal of Neuroscience Methods in May-2009 under the title, "A novel technique for examining human brain activity associated with pedaling using fMRI."
Micronor is a leading supplier of discrete control and feedback products for industrial automation and process control industries as well as mil/aero and other harsh environment applications. Motion control products include integrated position transducers, rotary encoders, resolvers, cam timers, programmable limit switches, motorized potentiometers, pulse generators and ergonomic pendant stations. Micronor was founded in 1968 and has regional headquarters in both the United States and Europe.
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