Voice Coil Actuator for Precision Motion Systems: Applications, Benefits & Design Guide
In modern high-performance engineering and industry, ultra precise motion control is very important for medical devices, semiconductor manufacturing, aerospace and robotics fields. The voice coil actuator has become one of the widely chosen solutions to meet these requirements with its smooth, fast, zero-backlash features.
This blog explains what a voice coil actuator is, its applications and advantages, along with a practical guide on voice coil actuator design.
What is a Voice Coil Actuator?
A voice coil actuator is a type of direct drive linear or rotary actuator that works on the principle of Lorentz force which states that when current flows through a coil that is within the magnetic field it will produce force proportional to the current and this will create the motion.
Instead of using gears, lead screws, and belts, the actuator does not use those mechanisms. Because of this the linear voice coil actuator gives very smooth and precise motion, suitable for high-precision application.
Two types of voice coil actuator:
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Linear actuator - This produces linear or straight line motion.
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Rotary actuator - This produces circular or angular motion.
How Does a Voice Coil Actuator Work?
The basic electromagnetic principle that causes the direct drive actuator to operate is as follows:
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A coil is placed inside a permanent magnetic field
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Current is supplied to the coil
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A force is created (Lorentz force)
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The coil moves according to the amount of current supplied
Because the force is proportional to the current the engineers are able to control the position, velocity and acceleration with a high degree of accuracy.
Voice Coil Actuator Applications
Voice coil actuators have diverse applications where precise and quick responses are needed.
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Medical devices - Surgical robots, MRI scanners and many diagnostics machines employ direct drive actuators for precisely controlled, smooth motion.
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Semiconductor manufacturing - Linear voice coil actuators can be incorporated into wafer stages or for inspections, where extremely accurate position resolution of sub-nanometers is required.
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Aerospace and Defense applications - These range from positioning and stabilization of space-based optics to vibration isolation systems.
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Industrial automation - The repeatability and speed required for pick-and-place machines, high-speed inspection systems and precise assembly are supplied by precision motion control actuators .
Advantages of Voice Coil Actuator
1. Zero Backlash - As there are no gears or mechanical transmission there is no backlash which allows for extremely precise positioning.
2. High precision and repeatability - Force is linear and predictable and therefore good for a closed loop system.
3. Fast response time - Low moving mass which leads to very quick acceleration and deceleration.
4. Quiet and Smooth motion - There are no wearing frictional components hence smooth and silent operation and low vibration.
5. Light and compact - Suitable for space saving applications.
Voice Coil Actuator Design Guide (Step-by-Step)
Developing a precision motion control actuator system needs good planning. Let's outline the steps for the development of a voice coil actuator.
1. Define Motion requirements
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Work out what are the following parameters:
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Stroke length for a linear system or angular travel for a rotary system
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Speed required and acceleration profile
Linear voice coil actuators are common in semiconductor equipment with positioning required down to the micron and relatively short stroke lengths.
2. Calculate Force requirements
The force is the product of the following:
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Load mass
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Required acceleration
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External forces acting on the actuator, such as gravity and friction
Careful design of the voice coil and magnet system is important.
3. Select the suitable linear or rotary voice coil actuator
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Linear actuator is most commonly used for positioning stages, scanners etc.
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Rotary actuator is useful when an angle of motion is required like mirrors or valves.
4. Thermal control
The heat generated by the actuator voice coil is a common problem in the design. There are several solutions:
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Heat sinks
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Air Cooling
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Duty cycle optimization
This helps in making the precision motion control actuator perform well for the intended use.
5. Feedback and Control system
For highly precise applications where exact positioning and speed is essential. We require feedback devices:
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Linear encoders
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Hall sensors
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Optical feedback systems
By incorporating these devices a closed loop voice coil actuator can be designed.
Linear vs Rotary Voice Coil Actuator
|
Feature |
Linear Voice Coil Actuator |
Rotary Voice Coil Actuator |
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Motion |
Linear |
Angular |
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Use Case |
Positioning systems |
Mirror/valve control |
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Precision |
Extremely high |
Extremely high |
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Stroke/Range |
Short linear stroke |
Limited angular rotation |
Conclusion
Voice coil actuators represent one of the most viable and potent solutions in precise motion systems, and whether you require a linear or a rotary voice coil actuator, it's important to know the underlying principle of precision motion control actuator design for the greatest system performance possible.
Speed, precision, and reliability are what makes coil actuators revolutionize engineering and automation for the coming future, and if it's high performance motion you need within your system, then Norck Robotics can help provide the right guidance,
Contact us now to explore the parameters and specifications for your direct drive actuator solution and for more information.
FAQ
1. What is a voice coil actuator used for?
It is used for precise motion control in areas such as medical instrumentation, semiconductor fabrication and optical systems.
2. How does a voice coil actuator work?
Voice coil actuator's principle is based on the electromagnetic force, when a current is applied to the voice coil that is submerged within a magnetic field.
3. What are the advantages of voice coil actuators?
They provide advantages such as zero backlash, high accuracy, rapid response time, smooth operation and low maintenance.
4. How to design a voice coil actuator system?
When designing a voice coil actuator system, the requirements of motion must be established; forces must be determined, appropriate actuators selected; heat issues managed; and feedback and control systems must be integrated.