Industrial Automation Magazine India

Harnessing the Potential of Voice Coil Motors in Mechatronics

Published on : Friday 15-12-2023

Compared to stepper motors, voice coil motors offer significantly higher bandwidth and faster response times.

Voice Coil Motors are the simplest type of electric motors, which consist of two separate parts: the magnetic housing and the coil. Voice coil motors are brushless and do not utilise commutation. Their structural stability can support high positioning resolutions presented by external position sensors and motion controllers.

Akribis Systems offers three series of high-performance voice coil motors covering a range of sizes and force densities.

The linear voice coil motor utilises a magnetic field generated by permanent magnets in connection with a coil of wires to produce an electric driving force for high precision position control. Since the mass of the moving coil is typically low, the speed and acceleration of the voice coil motor are very high and the settling time is very short.

Moreover, because the inductance of a voice coil motor is typically low, the resulting low electrical time constant enables the voice coil motor to have a very fast response and bandwidth.

Besides, the direct-drive features benefit for the voice coil motors such as zero cogging, zero backlashes, smooth motion at low speeds, and limitless resolution.

Voice coils are usually made as lightweight as possible, making them delicate. Passing too much current through the coil can cause it to overheat Voice coils wound with flattened wire, called ribbon-wire, provide a higher packing density in the magnetic gap than coils with round wire. Some coils are made with surface-sealed bobbin and collar materials so they may be immersed in a Ferro fluid which assists in cooling the coil, by conducting heat away from the coil and into the magnet structure. Excessive input power at low frequencies can cause the coil to move beyond its normal limits, causing distortion and possibly mechanical damage.

 

How do voice coil motors work?

A simple linear voice coil motor consists of a tubular coil of wire. The wire is situated within a magnetic field. The magnetic field is produced by permanent magnets embedded in the inside diameter of a ferromagnetic cylinder.

The cylinder is arranged such that the side of the magnets that faces the ferromagnetic cylinder has the same polarity as the cylinder. The opposite side of the magnets facing the coil has the opposite polarity. An inner core of ferromagnetic material set along the axial centerline of the coil, joined at one end to the permanent magnet assembly, is used to complete the magnetic circuit.

 

Benefits of industrial automation with voice coil motors

Reliability – voice coil motors are highly reliable and durable, making them ideal for industrial automation. They are designed with a self-contained linear drive system that requires no external components or lubrication, making them virtually maintenance-free. Their robust construction allows them to withstand extreme temperatures, shocks, vibration, and other environmental factors. This makes them ideal for industrial automation systems that require a high degree of reliability and performance.

Accuracy – Voice coil motors are highly accurate and precise. They are designed with a self-contained linear drive system that provides precise control over the speed and direction of motion. This allows them to perform complex tasks with a high degree of accuracy and repeatability.

Ease to use – voice coil motors are also highly user-friendly. They require no complex programming and can be easily integrated with other industrial automation systems. Additionally, voice coil motors are able to quickly adjust to changing conditions in the environment, meaning they can remain effective for a long period of time. This makes them an ideal solution for industrial automation applications that require continuous and reliable performance.

Cost-effectiveness – As they require less energy and produce less waste, they help to reduce overhead costs associated with industrial automation. Additionally, they are able to reduce labor costs associated with manual operation and are able to reduce downtime and increase production efficiency.

 

Applications of voice coil motor

Voice coil motors are versatile and find applications in a multitude of industries due to their highly precise control and direct linear motion.

Data storage: In hard disk drives, voice coil motors are responsible for moving the read/write head. The precision and speed of a voice coil motors ensure rapid access to data stored on the disk.

Optical instruments: In cameras, particularly in auto-focus mechanisms, voice coil motors adjust the lens position with high precision to maintain sharp image quality.

Medical applications: Medical devices such as ventilators and infusion pumps also utilise voice coil motors to control fluid movement with high precision.

Robotics and industrial automation: voice coil motors find usage in robotics and automation where precision, quick response and smooth control are paramount.

 

Tips for choosing and using voice coil motors

When selecting a voice coil motor for a specific application, certain factors must be considered. The required force, velocity, and stroke length should be determined to ensure the motor meets the desired specifications. The required duty cycle, operating environment and temperature range should also be evaluated.

Careful consideration should be given to the electrical and mechanical integration of the voice coil motor within the system. Compatibility with the drive electronics, surrounding materials, and any position sensing requirements must be taken into account to facilitate seamless integration and optimal performance.

Proper cooling and thermal management systems should be implemented to ensure the optimal operating temperature range of the motor. Overheating could lead to reduced performance, decreased lifespan, or even motor failure.

Regular maintenance checks and lubrication of moving parts should be performed to ensure the longevity and reliable operation of voice coil motors. Follow the manufacturer's guidelines and recommendations for preventative maintenance and periodic inspections.

Voice coil motors are versatile electromagnetic transducers with numerous applications across various industries. Their compact size, precise control, and fast response make them an excellent choice for many systems requiring accurate positioning and dynamic motion control. Understanding the construction, working principles, and comparing them with other motor types provides valuable insights when selecting and utilising voice coil motors in diverse applications.

 

Comparing voice coil motor with other motor types

Voice coil motors have distinct advantages when compared to other motor types. One notable advantage is their low electrical resistance, enabling efficient power consumption. Voice coil motors deliver higher force-to-weight ratios than other types of actuators, making them desirable for applications where weight and size are critical factors.

Compared to stepper motors, voice coil motors offer significantly higher bandwidth and faster response times. However, stepper motors excel in holding torque and low-speed control. Brushless DC motors (BLDC) exhibit higher torque capabilities but are more complex in design and control.

Durga Mechatronics offers Akribis make voice coil motors, delivering unparalleled accuracy and reliability for your automation needs.