Solved Servo Applications

Ventilator Motion Control

Medical ventilators provide breathing assistance for patients with the inability to do so. ADVANCED Motion Controls has developed ventilator control solutions for numerous ventilator models over the years, most notably a portable ventilator and a high-frequency oscillatory ventilator.


Portable Ventilator Control

Available now for decades, this particular ventilator is in use at hospitals and clinics worldwide. Still considered one of the most dependable, high performance ventilators in the market today with computerized turbine control, it was the first homecare ventilator to match synchronization with patient’s efforts. Servo drives are required to deliver precise rotational velocity and direction control of brushless motor driven scroll compressor.

Solution Requirements

The ventilator manufacturer had numerous requirements that the servo drive needed to meet. These design parameters included:

  • Inexpensive
  • Small size and with robust operability
  • Demanding speed and acceleration/deceleration control to deliver high rates of volumetric air changes
  • High bandwidth for outstanding overall system response
  • Low failure rates expected
  • Long serviceable life
Our drive solution also had to ensure the key feature in this particular ventilator model: Portability. The portable design improves patient transfers and overall safety by allowing flexibility. If necessary, patients can arrive on an ambulance and be transported to the emergency room, then the operating room and finally to the recovery room without ever having to be disconnected from the ventilator.

Solutions Technology

Efficient and streamlined design

In order to most effectively meet the design parameters, we decided to design a completely new custom servo drive for this application.

  • Analog architecture with tuning and adjustments for long-term reliability and simplified installation
  • Open case design for reduced cost and easy maintenance if necessary
  • 100% specifications verification and test guaranteed high quality/design

Objective review

After integrating our servo drive, the final product exceeded the customer's initial design expectations. The success was lasting too. Even after years of service, the drive proved to maintain this exceptional level of performance.

In production well over 20 years with over 80,000 units in operation!

Decades have passed, and this ventilator design has seen multiple model updates and changes in company ownership since its inception, but the units produced today are still based on this design and still use our servo drives. Our drives exceeded the quality goal expectation of 99.7%, so they've earned the manufacturer's trust.


High-Frequency Oscillatory Ventilator Control

This diaphragm controlled, high-frequency oscillatory ventilator (HFOV) provides alternative mechanisms of oxygen exchange and is used in cases where critical care patients can’t breathe on their own.  Delivery of breathable air is smaller and more frequent and generally meant for elderly adults and neonatal patients, so the ventilator control system is a little different. The servo drives in this model allow for precision operation of voice coil motorized servo driven piston pump system.

Voice coils are commonly used in speakers to provide the back and forth motion, and can be electrically operated with a servo drive much like a servo motor can. In this case, current controls the linear force rather than the rotary torque, allowing the voice coil to push the piston.

high frequency ventilator control
high frequency ventilator control

Solution Requirements

The customer needed a common servo drive platform for various models of this ventilator design.

The system needed to be capable of producing frequency variability of 3 - 15 Hz oscillation. Even with the higher frequency, the servo drive and overall system needed to provide extremely precise air pressure and volume delivery with no deviation. This meant the drive needed fast acceleration and deceleration response to provide precise volumetric flow. The drive also needed high velocity/bandwidth with no ripple

As with any life-saving device, reliability is critical. This can be a challenge in systems with constant, high-frequency, mechanical vibrations. The drive needed to be capable of continued, unfaltering operation, providing an overall consistent performance regardless of operating conditions. Proving lifetime functionality required extensive initial testing.

servo drive for high frequency ventilator control

Solutions Technology

Standard product platform

  • High bandwidth and fast response
  • Matched (single-phase) voice coil motor tuning
  • Velocity mode
  • Fast accel/decel with low-to-no ripple

Over two decades of production

  • Market available, off-the-shelf analog servo amplifier used and offered to any customer today
  • Original initial production units still operating with zero failures
  • Lifetime reliability test still in progress
  • Recognized by customer with highest quality audit award
high frequency ventilator control

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