Small DC drive systems revolutionising healthcare

Exploring Drive System Technologies for Healthcare Applications

Small drive systems often play a crucial role in advancing healthcare technology, powering a diverse range of medical devices essential for diagnostics, treatment, and patient care. From precision surgical tools to prosthetic limbs, these systems must meet demanding requirements for precision, reliability, smooth operation, and long service life.

Several factors, including commutation method and motor form factor, can significantly influence the suitability of drive systems for healthcare applications. Moreover, the ability to incorporate specific features such as sterilisability or customise aspects of the solution adds to their versatility and applicability in medical device applications.

Desirable Features in Small DC Drives for Medical Applications

Small motors, often referred to as miniature drives or micro-drives, are available in a range of types, each with its own advantages and suitability for specific applications.
Here are some common types of drives and their best-suited applications:

Brushed DC Motors

• Best suited for Applications where simplicity, cost-effectiveness, and moderate performance are acceptable.
• Examples: Portable medical pumps, infusion devices, mobility aids (e.g., electric wheelchairs).
   

Brushless DC Motors

• Best suited for applications requiring high efficiency, reliability, and precise control of speed and position.
• Examples: Surgical robotics, medical imaging equipment (e.g., MRI, CT scanners), ventilators, anaesthesia machines.
   

Stepper Motors

• Best suited for applications requiring precise positioning and control, with the ability to move in discrete steps.
• Examples: Laboratory automation systems, robotic surgery systems, automated medication dispensers.
   

Direct Linear Drives

• Best suited for applications requiring precise and dynamic linear motion without the need for mechanical transmission elements.
• Examples: Automated sample handling systems, robotic-assisted surgery devices, high-speed imaging systems, dynamic pumps, testing systems.
   

Gear Motors

• Best suited for applications requiring increased torque or lower output speeds in a compact package.
• Examples: Patient lifts, adjustable hospital beds, robotic rehabilitation devices.
   

Each type of drive has its strengths and limitations, and the choice depends on factors such as required performance, precision, reliability, size constraints, and cost considerations. Integrating the appropriate motor type into medical devices is essential to ensure optimal functionality, safety, and patient care.

Tailored Solutions for Medical Applications

The medical industry often demands specialised drive systems to meet unique technical requirements. Engineers specialising in medical technology collaborate closely with clients to develop tailored motor and control systems. These systems can be based on modular standard solutions or fully customised designs to ensure optimal performance and reliability that is often critical for healthcare applications.

Let us look a little deeper into some examples to see how customisation can add value.

Endodontic Hand Tool

Application Description:

• Endodontic handpieces are utilised during root canal treatments to clean and shape the tooth’s root canal.
• Key features of modern endodontic instruments with electric drives include low speed combined with constant and precise torque, programmable settings, automatic safety stop, automatic reverse functions, and optionally, cordless operation for enhanced mobility.
   

Typical requirements:

• Slim and lightweight motor for ergonomic handling, high-level balancing to minimise vibrations and reduce fatigue, lower electric motor speeds for reduced noise levels and improved patient comfort, wide speed range and constant high power for flexibility in dental treatments.
   

Possible Micro Drive Solution:

• Drives optimised for high-speed operations, maintaining a comfortable temperature range, and ensuring smooth motion with minimal vibrations.
• Either a DC or BL motor, optionally paired with a gearhead and custom wiring/interconnect to save space.
• Drive diameter typically falls between 12 to 20 mm.
• The motor speed needs to be reduced to achieve a tool speed ranging typically from 300 to 1000 rpm.
   

Portable Injection System

Application Description:

• A portable injection system utilising a spring-loaded needle for tissue penetration, commonly used in biopsy procedures to obtain tissue samples for examination, particularly for cancer diagnosis.
   

Typical requirements:

• High efficiency drive required for battery-operated systems to maximise force output within limited current constraints.
• Need for high spring force and speed to minimise spring loading time, necessitating a high-power drive operating intermittently for short periods (1–2 seconds ON-time).
• High efficiency linear motion to allowing for smaller drive size.
   

Possible Micro Drive Solution:

• Highly efficient DC motor to maximise force output while operating within limited current constraints.
• Incorporation of ball screw technology for superior efficiency.
• Integration of encoder and optionally control electronics to save space for precise and intermittent operation, ensuring optimal performance during short ON-time periods.

Conclusion:

Small DC drive systems are often the unsung heroes of medical devices. They are driving innovation in modern healthcare, offering compact precision and reliability across a wide range of applications.

Explore small DC drive systems at Erntec Pty Ltd
www.erntec.com.au

For more information: https://www.erntec.com.au/microdrives-homepage.