A brushless DC motor for demanding operating room applications

A sterilizable EC-4pole 30 from maxon motor

A sterilizable EC-4pole 30 from maxon motor

A sterilizable EC-4pole 30 from maxon motor

maxon’s new brushless electric motor, the EC-4pole 30, delivers high torque (106 mNm) and is sterilizable – a perfect drive for hand-held surgical tools.

Swiss drive specialist maxon motor has developed a robust brushless DC motor for hand-held surgical tools: the EC-4pole 30. Featuring two pole pairs, this DC motor provides a nominal torque of 106 mNm and an output of 150 W. It has a hermetically sealed rotor, meaning that it can withstand over 1000 autoclave cycles.

Need to operate at overload? No problem!

The EC-4pole 30 is equipped with the special ironless maxon winding, which makes it highly efficient. Another key feature is that the torque and current behave linearly and the drive can be overloaded. It is available with an optional Hall sensor, as well as with a hollow shaft with a diameter of up to 4.1 millimeters.

With the EC-4pole 30, engineers get a first-class drive for surgical hand tools that work flawlessly under the tough conditions of operating rooms.

maxon offers a complete line of dc brushed and brushless motors, gearheads and controllers. Contact us to help find the right solution for your application. info@maxonmotor.com

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High performance drive in a small package

maxon's NEW brushless EC4mm motor and gearhead

maxon’s NEW brushless EC4mm motor and gearhead

maxon sets new standards in micro drives

maxon’s smallest DC brushless motor is only four millimeters in diameter and comes in two different lengths. Certified in accordance with ISO 13485, the new brushless micro drive is ideal for medical applications.

The EC 4 brushless DC motor is maxon motor’s ultra-compact solution to the market’s needs. As the smallest micromotor to come from the Swiss manufacturer, the EC 4 is only four millimeters in diameter. It is available in two lengths, with power ratings of 0.5 and 1 W. Equipped with an ironless maxon winding, the EC 4 stands out for its robust design, high power density, and energy efficiency.

EC4 measuring tool

EC4 measuring tool

maxon has the matching gearhead

Combined with the GP 4 planetary gearhead, the EC 4 becomes a compact drive for use in micropumps, analytic and diagnostic devices, and laboratory robots. Precise and reliable, it can adjust lenses, dispense fluids, or position sensing devices. All units meet the ISO 13485 medical standard, which makes this maxon micro drive the perfect choice for applications in medical technology.

maxon offers a complete line of dc motors, gearheads and controllers. Contact us to help find the right solution for your application. info@maxonmotorusa.com

Circulatory Support without Surgery for Heart Failure Patients

The cardiac pump is a mere 6 millimeters and 6.5 centimeters long. Image ©Procyrion

The cardiac pump is a mere 6 millimeters and 6.5 centimeters long. Image ©Procyrion

Intra-aortic pump powered by miniature brushless DC motors provides heart failure patients an aid to help hearts rest and heal.

Chronic heart failure patients draw hope from a new technology. A team of life science entrepreneurs in Houston, Texas has developed the first catheter-deployed circulatory assist device intended for long-term use. Procyrion, Inc.’s Aortix™ provides a minimally invasive treatment option for the more than two million chronic heart failure patients in the USA alone who are too sick for medication. This pre-clinical cardiologist tool dramatically reduces risks associated with circulatory support devices and enables treatment of younger, healthier patients before progressive damage occurs.

Assisting the natural function of the heart, the intra-aortic pump has been thoughtfully designed as an alternative to large, cumbersome surgical devices currently providing full circulatory support. Unlike these devices, Aortix provides minimal procedural risk. Measuring approximately 6 mm in diameter and 6.5 cm long, a cardiologist can deliver Aortix via a catheter in the femoral artery to the descending thoracic aorta. Once the catheter sheath is retracted, the self-expanding nickel-titanium anchors deploy to affix the pump to the aortic wall.

Aortix accelerates a portion of the body’s native blood flow within the pump and pushes it through fluid entrainment ports directed downstream. The jets entrain native aortic flow, transferring energy to the cardiovascular system and increasing blood flow to vital organs such as the kidneys. Additionally, in a model of chronic heart failure, Aortix decreased energy consumption of the heart by 39 percent, allowing the heart to operate more efficiently, encouraging cardiac rehabilitation and recovery.

The cardiac pump is a mere 6 millimeters and 6.5 centimeters long. Image ©Procyrion

The cardiac pump is a mere 6 millimeters and 6.5 centimeters long. Image ©Procyrion

Procyrion has been working with maxon for almost two years to develop a motor for this unique and demanding application. The basis for the Aortix device is a maxon EC6 motor with some customization including the electrical lead, shaft length, and bearing assemblies – all designed to make the pump durable and biocompatible. maxon also designed a high efficiency motor core for this application, which extends battery life and produces less heat so it doesn’t adversely affect the circulating blood. In addition, maxon is working closely with Procyrion to implement a magnetic torque drive, so the motor could be mounted inside a hermetically sealed chamber. This configuration eliminates the possibility of blood entering the motor core. The magnetically coupled pump arrangement is a method sometimes used for giant pumps in the oil field, but because of maxon’s breadth of experience across multiple industries, the company was able to help the Procyrion team successfully transfer this technology to a miniature scale medical application.

Each Aortix device consists of a small, continuous flow pump mounted within a self-expanding anchoring system. The anchored pump attaches to a flexible power lead, which can be tunneled to a desired transdermal exit site or to a Transcutaneous Energy Transfer (TET) system for subcutaneous implantation without an indwelling power lead.

Presently, the device can operate for over eight hours on a single battery pack. The external battery pack and control unit have been designed to be “hot swappable”, meaning the battery can be changed without needing to stop the device. A variety of charging devices can be used.

“Aortix reduces the heart’s energy consumption by 39 percent.”

The Procyrion team has also built a TET charging system that enables the battery to be charged wirelessly. This design has the potential to significantly reduce the risk of infection, common with other implantable heart pumps.

Because traditional assist devices replace heart function rather than support it, device failure can be fatal. With Aortix, a partial support device which doesn’t obstruct native blood flow, failure is not life threatening. Should the pump fail, the device can easily be retrieved and replaced in another minimally invasive, catheter-based procedure.

driven magazine: The operating room of the future

maxon driven magazine

maxon driven magazine

High-tech for health and beauty

The new issue of driven – the maxon motor magazine – is now available. In this issue, we peek over the shoulder of a surgeon using the da Vinci surgical robot, present a new device for cardiac patients and take a look at the world’s first cordless tattoo machine.

The latest issue of driven is all about state-of-the-art medical technology, like the da Vinci surgical robot. Learn why surgeon Daniel Seiler compares his equipment with a sports car, and learn how many maxon DC motors are integrated in the system. You can also read how medical researchers are developing an innovative non-invasive cardiac pump. Anthony Mayr, Senior Project Leader at maxon motor, explains how engineers deal with the tough environmental conditions for drive systems in operating rooms.

driven also ventures into the world of tattoo art. We introduce a Swiss company that has developed the world’s first cordless tattoo machine to the market and show its advantages.

This issue’s technical article looks into the topic of energy efficiency. A suitable controller is not the only requirement for driving minimotors in an energy-efficient way. Mechanical components play a key role in keeping losses low.

driven is published as a tablet magazine and can be downloaded free of charge from the App Store or from Google Play. If you prefer the printed edition, order your personal copy today.

For more information, go to: magazine.maxonmotor.com

Getting a second grip on life

The Michelangelo Hand © 2014 Ottobock

The Michelangelo Hand © 2014 Ottobock

Losing a hand in a tragic event turns everyday tasks into a constant battle. Nothing is the way it was before and even small things suddenly seem impossible. The hightech Michelangelo Hand prosthesis gives back quality of life to people who lose a hand. maxon DC brushless motors play an important role.

The human hand is a masterpiece of nature and helped us to become what we are today. We use our hands to assemble the tiniest clockworks, to throw balls, or to communicate when language barriers become difficult. This makes life very hard for people who have lost a hand due to an injury or an accident. Patrick Mayrhofer personally understands such struggles. In a job related accident, he injured his hands so badly that he chose amputation of his left arm shortly afterwards. Yet, the young man did not let this fate knock him down. “I’m very focused on my goals, and when I put my mind on something, I usually succeed at it.” He does not want any special treatment and he does not need it either. With his new prosthetic hand, he masters practically all day-to-day situations without difficulties.

The impossible becomes possible
His prosthesis, called the Michelangelo Hand, was developed by Ottobock in Vienna. It can perform seven different gripping movements, which the user can trigger by contracting the muscles in his stump. Tasks that were previously impossible suddenly become possible: Balancing a plate on one’s palm, taking an egg from a box, holding a menu, or even peeling a banana. In the words of Martin Wehrle, another Michelangelo user: “With many movements, I simply grab the object without thinking much about it.”
To replicate the human hand as closely as possible, the engineers at Ottobock needed to experiment for many years and had to miniaturize all the electronic and mechanical components in the prosthesis. As a result, it weighs only 520 g and is comfortable to wear. The prosthesis does not only look natural, but it also feels natural – for example when shaking hands. This is due in part to the artificial wrist with its dampened movements. The mechanical systems enabling the gripping functions are driven by a brushless maxon motor, type EC 10, and an adapted version of the EC 45. The first motor drives the thumb, the second is in charge of the main drive for the index and middle fingers. The ring finger and little finger move passively. The EC motor for the thumb has an ironless winding and is also equipped with a worm shaft customized by maxon motor.

The Michelangelo Hand © 2014 Ottobock

The Michelangelo Hand © 2014 Ottobock

Drives with high power density
maxon motor has been supporting Ottobock with special solutions since the company began its development of Michelangelo. Requirements to the drive system include a high power density, smooth running, and resistance to high axial shaft loads. maxon brushless DC motors meet all these requirements. Additionally, they have a long life span.

Sensor for reliable gripping
The interface with the human body is another important aspect of the Michelangelo prosthesis. Ottobock uses electrodes to measure the electrical pulses in the muscles at the stump and sends these signals to a processor. The Axon-Bus data transfer system is extremely fast and reliable. It makes handling the prosthesis easy and intuitive for the user. The harder the user tenses their muscles, the faster and stronger the hand grips. Simultaneously, a sensor in the thumb measures the closing force. This allows for accurate control of the gripping force when an object threatens to fall down.
The Michelangelo Hand gives many users the chance of returning to work. This is especially true of people in the prime of their life who have a family and want to work. These people can profit from the many applications of this prosthesis. Hans Dietl, managing director of Ottobock, says: “We want to give people the highest possible degree of mobility and independence. We work on this daily and will continue to do so in the future.”

Introducing the new 4 mm micro motor and gearhead

maxon's brushless EC4 motor and gearhead

maxon’s brushless EC4 motor and gearhead

maxon motor was challenged to deliver maximum power in the smallest possible space and the result is the EC 4 brushless motor. maxon motor introduces the EC4, a 4 mm diameter brushless DC motor and gearhead. The typical issue found with micro drives of this size is the output power is too low for the application requirements because of the physical limitations. maxon increased the performance of this tiny motor using the latest winding technology along with the most powerful magnets available. This motor is available in two lengths; short version with 0.5 W nominal power or long version with 1.0 W nominal power.

maxon also incorporated a high quality gearhead to ensure optimum continuous running. High performance ceramics are used for the gearhead carrier to make the motor capable of high input speeds and drive torques. The speed/torque gradient of the EC 4 is an impressive 50,000 rpm mNm-1 with a continuous torque of 0.4 mNm. There are options on the windings and encoders as well as different reduction ratios on the new 4 mm planetary gearhead.

This 4 mm brushless DC servo motor is becoming the benchmark solution in miniature pumps, surgical robots, diagnostic devices, endoscopes and anywhere miniaturization is critical. maxon motor has explored the limits of technical boundaries with this EC4 motor development. For more information and product specifications, visit www.maxonmotorusa.com  or contact us at info@maxonmotorusa.com .

Surgical Simulators

Surgical simulators that impart the actual feeling of performing surgery provide obvious training benefits. Here’s how one company helps clinicians perfect the practice.

Immersion Medical Simulator - the LapVR System

Immersion Medical Simulator – the LapVR™ System. The essential skills and procedures exercised while using the LaparoscopyVR Simulation System provide valuable training for surgical students prior to performing actual surgery. This helps to prepare the next generation of surgeons for laparoscopic surgery

Immersion Medical (Gaithersburg, MD) designs and manufactures surgical simulators. Similar in idea to that of flight simulators for pilots, a surgical simulator allows a medical student to practice an entire surgical procedure without the threat of harming a patient. Simulator training has also been found to reduce training costs because of procedural and instructor time savings, reduce errors resulting in fewer complications, and contribute to faster time to competence and reduced equipment damage, as well.

The company’s latest product offering in their simulation line is the LaparoscopyVR™ (LapVR) Virtual Reality Surgical Simulator. Designed by reviewing the Fundamentals of Laparoscopic Surgery curricula endorsed by the Society of American Gastrointestinal Endoscopic Surgeons, receiving input from surgeons at world renown institutions, and conducting in-depth research of training needs, the LaparoscopyVR Surgical Simulator provides a platform for virtual reality training. The system’s hardware and software interface simulates laparoscopic surgery and provides virtual reality training in the essential skills required of laparoscopic procedures. The simulator comes packaged as a complete system with selected software modules and height adjustable cart, monitor swing, foot pedal, camera and tools.

The LapVR Surgical Simulator’s recorded performance metrics allow medical institutions to assess individual and team performance. The simulator supports three fully instrumented tools—two trocars with interchangeable simulated tool tips and an endoscopic camera with 0, 30, and 45 degree lenses and high-speed optical tracking technology to accurately monitor tool motion.

Immersion completed the entire design and built of the device from the ground up, purchasing components from other vendors only when necessary. The base laparoscopy surgical simulator includes an Essential Skills module with fifteen skill exercises, a Laparoscopic Cholecystectomy (LapChole) module with eighteen cases and an Administration module that provides individualized instructional design and tracking. The Essential Skills module includes unique exercises for developing camera navigation, cutting, clipping, adhesiolysis, and hand transfer skills. The LapChole module provides a simulated environment for removal of the gall bladder, one of the most common types of laparoscopic surgeries in the U.S.
Using haptic, or force, feedback, the LaparoscopyVR system realistically emulates the feeling of the forces that would be encountered while performing laparoscopic surgery. This means that feedback while doing the simulation must be as close to reality as possible. Immersion calls this ‘Engaging the Sense of Touch”. The haptic feedback needed to generate that level of feeling required motors with very specific characteristics.

After researching the wide array of products available in the market, Immersion chose motors designed and manufactured by Maxon Precision Motors (Fall River, MA) for the project. “We use our motors in a unique way, different than how most standard motors are used,” said Rob Cohen, Director, Business Development for Immersion. Most DC motors are run at high speeds through transmission devices that are expected to generate the required forces, torques and speeds needed to drive a load, spin a tool or provide linear actuation. According to Rob, “Our application is different. We almost always run the motor in a stalled condition. The motor is not moving and that’s when we need it to generate torque.”

Furthermore, the company didn’t have the luxury of using high gear ratio transmissions because such devices must also be back drivable. That means that at appropriate times within the simulation, the user must be able to move the proxy surgical instrument without feeling any resistance or motor cogging. Maxon’s DC motors are known for their ability to run without cogging and with low background friction.

Additional features of Maxon’s DC motors with rare earth magnets include a rhombic, moving coil design, which provides for long life, low electrical noise, fast acceleration and high efficiency. It’s the ironless rotor that allows for the motors’ zero cogging and simple control.

Maxon motors are ‘torque dense’ as well, which means that for a given size motor and power, the components produce a lot of torque. This allows smaller motors in the Maxon line to produce a given output, all in a smooth, non-cogging design. Another benefit, non-technical in nature, to using Maxon components is that the company “…always delivers on time and frequently early, and we’ve never had an out of box failure,” Rob said.

The LaparoscopyVR virtual reality simulator provides the user with twelve degrees of freedom, ten of which are actuated with Maxon motors in them. Most of the motors are operated at zero speed and stall torque (or maximum continuous torque).

The tricky part of the design was heat management, according to Rob. “One of the motors used was located inside a plastic handle. The motor often ran near its thermal limit.” Because Immersion Medical uses motors in the scenario where they generate the most heat, a number of thermal management approaches were implemented in software to ensure the motors stayed within their operating envelope.

One area for improvement that’s always attractive to Immersion Medical is torque density. That is, is there a motor available in a smaller package that draws less current and produces more torque. As for documentation, Rob said that to someone trained in the skill of electromechanical design, Maxon’s printed materials are “…quite good and easy to use.”

 

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