While traditional positioning systems offer an adequate motion control solution for devices such as OR tables and hospital beds, they create other concerns related to their effect on the surrounding environment. Mechatronics provides an alternative that resolves issues with regard to space, noise, and cleanliness, which might be in question with another system.

By Tarek Bugaighis
The safety, reliability, precision, and speed of medical equipment play vital roles every day in hospitals, diagnostic centers, and other healthcare facilities. Technology has kept pace, equipping designers with a broadening range of options to integrate a variety of components into fully functioning systems delivering ever-higher levels of performance.

A newly developed actuator lifetime monitoring unit
indicates the approaching end of service life using an integrated
LED with color "status" lights.
Patient comfort and operator convenience have also been influencing the design and, ultimately, the operation of medical equipment. Features such as low retracted heights of imaging and treatment tables, effortless control of movement, and low operating noise levels can contribute to less stress and anxiety in patients and optimized working conditions for technicians and medical staff.

From this perspective an emerging trend in medical equipment is a transition from fluid-dependent hydraulic systems to cleaner and more environmentally friendly electro-mechanical systems. Designers further have realized how mechatronics can expand equipment functionality and reduce size and weight.

Mechatronics can be defined as motion and control in one package integrating mechanical and electronic technologies with application-specific software. Compared with hydraulic or pneumatic systems, mechatronics can make for a better prescription where motion will come into play.

As evidence, “indispensable” infrastructure for hydraulic systems necessitates a hydraulic unit, tank for oil, and filter systems, among other components; pneumatic-driven systems use air compressors, compressed air filters, and filter systems. Mechatronics takes a simpler path requiring only power and control wires to perform.

Telescopic pillars (or lifting columns) facilitate reliable vertical movements for surgical tables and other similar applications quickly and silently. Efficient gear technology keeps noise to a minimum.
Other issues linked with hydraulics and pneumatics include relatively high costs associated with system assembly and subsequent mounting; more maintenance over time will be necessary; noise levels will be noticeable; and the danger of hydraulic oil leakage will be ever-present.

For all these reasons, applications for mechatronics in today’s medical world are thriving.

Telescopic pillars integrated with guidance and control systems have simplified design work and advanced the capabilities for mobile surgery C-Bows and patient-positioning tables (even complete table systems have been pioneered); actuators and controls can combine to perform an array of motion requirements; and fully modular actuation systems have been engineered to enable precise and safe adjustment for hospital beds and stretchers.

Sampling several relevant equipment applications from SKF’s technology files can help illustrate how mechatronics is alive and well in the medical marketplace.
Medical Imaging: Gantry Systems
Medical imaging equipment requires precision positioning of the imaging technology and the patient. As one example of mechatronics in service, compact and silent linear actuators with high offset load and push/pull force capabilities have proven well-suited for cantilevered applications, such as computed tomography gantry tilt movements.

In some actuator versions, loads up to 12 kN can be lifted at speeds from 4.5 to 7.5 mm/sec. Incorporating a backup nut and limit switches as standard features provide added safeguards. Such actuation systems may further integrate a first failure safe control unit for safety in the operation of up to three actuators as well as corresponding accessories.
Operating Room: Surgical and Patient Tables
Surgical equipment must meet stringent hygienic standards and perform reliably and consistently. Specifying electro-mechanical actuation systems instead of conventional hydraulics eliminates the use of hydraulic fluids (and potential mess) in the operating room.

Telescopic pillars, or lifting columns, facilitate reliable vertical surgical table movements quickly and silently. Rigid aluminum profiles and precision glide pads enable such columns to lift offset loads without deflection. Efficient gear technology drives high push force capabilities and low noise levels.

As part of the system, actuators with inherent guidance function serve to extend (or retract) the several telescopic aluminum profiles of these pillars. Columns can run quietly and with minimal vibration at maximum speeds up to 45 mm/sec, depending on model. Stroke lengths up to 700 mm can be achieved and a low retracted height makes for optimized ergonomics and a good fit where space for systems may be cramped.

Making it easier to design and develop tables with precision movements and ease of operation, control boxes enable synchronization and control of multiple actuators for a flexible and application-focused actuation system. The proper combination of control boxes and actuators, when specified by designers at the outset, will promote compatibility of components and help reduce time spent in design, production, and assembly.

It should be noted that telescopic pillars can satisfy other applications, including patient-positioning tables typically used for medical imaging, treatment, and ophthalmic examination, among others where vertical action is required. Interest among OEMs for designers to create fully integrated medical equipment systems has led to the design and development of complete subsystem medical tables. These particular tables (one is mobile and the other is “fixed”) have now been incorporated into machines for urology. Their intrinsic, fully mounted mechatronics technology delivers precise multi-axis positioning of patients by doctors for greater accuracy in analysis and treatment with maximum ease and comfort.
Hospital Room: Patient Beds
Mechatronics has found a home in hospital rooms (and in similar patient-care settings) with one of the more innovative electro-mechanical solutions. A modular actuation system for beds is designed to enable their precise, safe, secure, and reliable power-driven adjustment and positioning. (Suitable applications extend to couches, stretchers, and physiotherapy and examination tables in various healthcare settings.) Specialized actuators, recliners, and control units and panels integrate easily into standard bed platforms.

Electro-mechanical actuation systems allow for precise, safe, secure, and reliable power-driven adjustment and positioning of hospital beds.
Beds equipped with such actuation systems can offer variable height adjustment; an adjustable backrest with CPR function; special positioning with auto-contour for comfortable sitting; and adjustable elevation of legs and knee-fold. Full electrical control is made possible by handsets, bilateral pedals, and selective function limiters. A manual “quick-release” mechanism safeguards in case of emergency.

Just as patients are monitored, strides have been made in monitoring the mechatronics components themselves. Most notable is an actuator lifetime monitoring unit introduced as an intelligent and unique electronic innovation for integration into electro-mechanical actuators. With this optional device, users can realize an unprecedented opportunity to follow and evaluate the status of an actuator continuously in its application. An integrated LED and a buzzer indicate the approaching end of service life. The data can be transferred easily to a PDA or hand-held computer and data-analysis software enables users to keep accurate records and proposed proactive maintenance plans.

The prognosis for mechatronics in medical equipment applications remains strong as technology evolves and applications arise. For designers, the outcome can be more viable system choices and solutions.
For additional information on the technologies and products discussed in this article, visit SKF USA at

Tarek Bugaighis is the Global Segment Manager - Medical & Healthcare for SKF Actuation and Motion Control. He is responsible for business development relating to products and technologies with applications in the medical industry. Bugaighis can be reached at 610-861-3705 or