Many hands help surgical robot redesign
Creating a robot for surgical use requires considerable system-level engineering as well as diverse design skills. New equipment for human medical use must conform to many regulations, be highly reliable and fail-safe, and offer improved levels of care compared to existing methods in order to be accepted by regulators and physicians. This combination of factors places a tremendous burden on the design team to provide in-depth expertise at many levels.
The Intuitive Surgical team charged with designing the da Vinci-S surgical robot (Figure 1) zoned in on one goal at the outset of the project – make the product easier to use, more reliable, and more serviceable than its earlier counterpart. One specific challenge was making the robot’s arms modular with localized control and self-contained calibration. These features would allow technicians to replace an arm without having to recalibrate the entire device.
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Control and calibration posed significant challenges in designing the machine. Its robotic arms require four control processors. One handles the endoscopic camera that offers the surgeon a stereoscopic view of the operating area; the other three control the motors that allow the arms to precisely replicate the surgeon’s hand motions. This demanded that the system provide precise motor control, automatically convert the surgeon’s x-y-z hand positions to the polar coordinates of the arm joints, and ensure fail-safe system operation.
Implementing these features forced the team to enter new design territory, including fiber-optic communications, FPGAs, and DSP-based servo motor control. Obtaining support in these new areas from component vendors, however, proved difficult. Medical equipment manufacturing does not offer the production volumes for individual components that can attract vendors’ attention. As a result, the design team could not obtain the level of support needed from individual vendors.
Designers found that support by turning to Avnet, an electronic components, computer products, and technology services distributor. Avnet’s knowledge about different vendors’ product lines aided in device selection. Its support engineering helped train the robot’s design team on the chosen products and aided the team in applying the technology appropriately. Additionally, the distributor helped streamline system integration by providing a single point of contact for gaining access to vendor expertise, eliminating the inevitable finger-pointing among vendors when integration efforts encounter obstacles. The distributor’s purchasing power also helped secure vendor support for the project despite the design’s relatively low production volume.
The successful conclusion of the design effort resulted from the teamwork between system design experts and the distributor, whose product expertise and vendor support freed the design team to concentrate its efforts on the system-level challenges without facing the learning curve of new technologies. Working with a distributor was the key to obtaining the support and outside expertise needed to bring the da Vinci-S to life.
Mike Druke has been the director of electrical engineering for Intuitive Surgical Inc. for the past five years. His organization is responsible for all vision, computer, communications, power, and motor servo electronics for the da Vinci surgical robot. Mike has more than 30 years of experience in the computer and communications industries. He has a BS in Electrical Engineering and an MS in Computer Science, both from Massachusetts Institute of Technology.
Intuitive Surgical
408-523-2100
mike.druke@intusurg.com
www.intuitivesurgical.com
