148 lines
8.2 KiB
Markdown
148 lines
8.2 KiB
Markdown
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title = "Voice Coil Actuators"
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author = ["Dehaeze Thomas"]
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draft = false
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category = "equipment"
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Tags
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: [Actuators]({{< relref "actuators.md" >}})
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## Working Principle {#working-principle}
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## Typical Specifications {#typical-specifications}
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## Model of a Voice Coil Actuator {#model-of-a-voice-coil-actuator}
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(<a href="#citeproc_bib_item_1">Schmidt, Schitter, and Rankers 2014</a>)
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## Driving Electronics {#driving-electronics}
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As the force is proportional to the current, a [Transconductance Amplifiers]({{< relref "transconductance_amplifiers.md" >}}) (voltage-controller current source) is generally used as the driving electronics.
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## Manufacturers {#manufacturers}
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| Manufacturers | Country |
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|-------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------|
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| [Akribis](https://akribis-sys.com/products/voice-coil-motors/avm-series) | Singapore (european distributors: [Maccon](https://www.maccon.de/en.html), [TDS PP](https://www.tds-pp.com/en/product/linear-voice-coil-actuators-avm/)) |
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| [Thorlabs](https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=14116) | |
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| [Geeplus](https://www.geeplus.com/) | UK |
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| [PBA Systems](https://www.pbasystems.com.sg/product/circular-voice-coil-motor-cvc/) | Singapore |
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| [Magnetic Innovations](https://www.magneticinnovations.com/) | Netherlands |
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| [H2tech](https://www.h2wtech.com/) | USA |
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| [Beikimco](http://www.beikimco.com/) | USA |
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| [Monticont](http://www.moticont.com/) | USA |
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| [Thorlabs](https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=14116) | USA |
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| [Celera](https://www.celeramotion.com/applimotion/products/direct-drive-frameless-linear-motors/voice-coil/juke-series-round-body/) | |
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## Voice Coil Stages {#voice-coil-stages}
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| Manufacturers | Country |
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|-----------------------------------------------------------------------------------------------------|-------------|
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| [TDS PP](https://www.tds-pp.com/en/product/voice-coil-actuator-stages/) | Switzerland |
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| [Thorlabs](https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_ID=14930) | USA |
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| [H2tech](https://www.h2wtech.com/category/voice-coil-stages#productInfo1) | USA |
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| [PBA](https://www.pbasystems.com.sg/product/circular-voice-coil-motor-cvca/) | |
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| [Monticont](http://www.pwr-con.com/ecommerce/default.asp?cat=Linear+Motor+Driven+Positioning+Stage) | |
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## Voice Coil for Vertical payload {#voice-coil-for-vertical-payload}
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Let's consider a spring-mass system with a force actuator (Figure [1](#figure--fig:voice-coil-vertical-mass-spring)).
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Parameters are:
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- `m`: the mass payload in [kg]
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- `k`: the spring constant in [N/m]
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- `Fmax`: the maximum force applied by the voice coil in [N]
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<a id="figure--fig:voice-coil-vertical-mass-spring"></a>
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{{< figure src="/ox-hugo/voice_coil_vertical_mass_spring.png" caption="<span class=\"figure-number\">Figure 1: </span>Mass Spring System" >}}
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`Dg`: deflection due to gravity in [m]
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`Df`: maximum stroke using the voice coil in [m]
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`f0`: the resonance frequency of spring-mass system in [Hz]
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\begin{equation}
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2 \pi f\_0 = \sqrt{\frac{k}{m}}
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\end{equation}
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\begin{equation}
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D\_g = \frac{m g}{k}
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\end{equation}
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\begin{equation}
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D\_f = \frac{F\_\max}{k}
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\end{equation}
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### Determine the required voice coil force as a function of the payload's resonance {#determine-the-required-voice-coil-force-as-a-function-of-the-payload-s-resonance}
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Let's fix `m` (payload mass) and `Df` (wanted motion induced by the voice coil).
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Then, let's vary `f0` and compute the corresponding `Dg`, `Fmax` and `k`.
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```matlab
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%% Fixed Parameters
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g = 9.8; % [m/s^2]
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m = 5; % [kg]
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Df = 5e-3; % [m]
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%% Suspension resonance is varied
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f0 = 0.1:0.1:20; % [Hz]
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```
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```matlab
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%% Other parameters are computed
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k = m * (2*pi*f0).^2; % [N/m]
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Dg = m * g ./ k; % [m]
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Fmax = k * Df; % [N]
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```
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<a id="figure--fig:voice-coil-force-fct-f0"></a>
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{{< figure src="/ox-hugo/voice_coil_force_fct_f0.png" caption="<span class=\"figure-number\">Figure 2: </span>Required Voice Coil Force as a function of the paylaod resonance and corresponding deflection due to gravity (mass is 5kg, stroke is 5mm)" >}}
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### Determine the payload resonance as a function of the wanted stroke {#determine-the-payload-resonance-as-a-function-of-the-wanted-stroke}
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Let's fix `m` (payload mass) and `Fmax` (maximum force applied by the Voice coil).
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Then, let's vary `Df` and compute the corresponding `Dg`, `f0` and `k`.
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```matlab
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%% Fixed Parameters
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g = 9.8; % [m/s^2]
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m = 5; % [kg]
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Fmax = 50; % [N]
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%% Wanted stroke is varied
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Df = 1e-3:1e-4:10e-3; % [m]
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```
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```matlab
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%% Other parameters are computed
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k = Fmax./Df; % [N/m]
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f0 = sqrt(k/m)/2/pi; % [Hz]
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Dg = m * g ./ k; % [m]
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```
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<a id="figure--fig:voice-coil-resonance-fct-stroke"></a>
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{{< figure src="/ox-hugo/voice_coil_resonance_fct_stroke.png" caption="<span class=\"figure-number\">Figure 1: </span>Resonance frequency and deflection due to gravity as a function of the wanted stroke (Max voice coil force is 50N and payload mass is 5kg)" >}}
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<a id="figure--fig:voice-coil-stiffness-fct-stroke"></a>
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{{< figure src="/ox-hugo/voice_coil_stiffness_fct_stroke.png" caption="<span class=\"figure-number\">Figure 1: </span>Resonance frequency and deflection due to gravity as a function of the wanted stroke (Max voice coil force is 50N and payload mass is 5kg)" >}}
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## Bibliography {#bibliography}
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<style>.csl-entry{text-indent: -1.5em; margin-left: 1.5em;}</style><div class="csl-bib-body">
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<div class="csl-entry"><a id="citeproc_bib_item_1"></a>Schmidt, R Munnig, Georg Schitter, and Adrian Rankers. 2014. <i>The Design of High Performance Mechatronics - 2nd Revised Edition</i>. Ios Press.</div>
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</div>
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