7.9 KiB
+++ title = "Voice Coil Actuators" draft = false category = "equipment" +++
- Tags
- [Actuators]({{< relref "actuators.md" >}})
Working Principle
Typical Specifications
Model of a Voice Coil Actuator
(Schmidt, Schitter, and Rankers 2014)
Driving Electronics
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.
Manufacturers
| Manufacturers | Country |
|---|---|
| Akribis | Singapore (european distributors: Maccon, TDS PP) |
| Thorlabs | |
| Geeplus | UK |
| PBA Systems | Singapore |
| Magnetic Innovations | Netherlands |
| H2tech | USA |
| Beikimco | USA |
| Monticont | USA |
| Celera |
Voice Coil Stages
| Manufacturers | Country |
|---|---|
| TDS PP | Switzerland |
| Thorlabs | USA |
| H2tech | USA |
| PBA | |
| Monticont |
Voice Coil for Vertical payload
Let's consider a spring-mass system with a force actuator (Figure 1). Parameters are:
m: the mass payload in [kg]k: the spring constant in [N/m]Fmax: the maximum force applied by the voice coil in [N]
{{< figure src="/ox-hugo/voice_coil_vertical_mass_spring.png" caption="<span class="figure-number">Figure 1: Mass Spring System" >}}
Dg: deflection due to gravity in [m]
Df: maximum stroke using the voice coil in [m]
f0: the resonance frequency of spring-mass system in [Hz]
\begin{equation} 2 \pi f_0 = \sqrt{\frac{k}{m}} \end{equation}
\begin{equation} D_g = \frac{m g}{k} \end{equation}
\begin{equation} D_f = \frac{F_\max}{k} \end{equation}
Determine the required voice coil force as a function of the payload's resonance
Let's fix m (payload mass) and Df (wanted motion induced by the voice coil).
Then, let's vary f0 and compute the corresponding Dg, Fmax and k.
%% Fixed Parameters
g = 9.8; % [m/s^2]
m = 5; % [kg]
Df = 5e-3; % [m]
%% Suspension resonance is varied
f0 = 0.1:0.1:20; % [Hz]
%% Other parameters are computed
k = m * (2*pi*f0).^2; % [N/m]
Dg = m * g ./ k; % [m]
Fmax = k * Df; % [N]
{{< figure src="/ox-hugo/voice_coil_force_fct_f0.png" caption="<span class="figure-number">Figure 2: Required Voice Coil Force as a function of the paylaod resonance and corresponding deflection due to gravity (mass is 5kg, stroke is 5mm)" >}}
Determine the payload resonance as a function of the wanted stroke
Let's fix m (payload mass) and Fmax (maximum force applied by the Voice coil).
Then, let's vary Df and compute the corresponding Dg, f0 and k.
%% Fixed Parameters
g = 9.8; % [m/s^2]
m = 5; % [kg]
Fmax = 50; % [N]
%% Wanted stroke is varied
Df = 1e-3:1e-4:10e-3; % [m]
%% Other parameters are computed
k = Fmax./Df; % [N/m]
f0 = sqrt(k/m)/2/pi; % [Hz]
Dg = m * g ./ k; % [m]
{{< figure src="/ox-hugo/voice_coil_resonance_fct_stroke.png" caption="<span class="figure-number">Figure 1: 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)" >}}
{{< figure src="/ox-hugo/voice_coil_stiffness_fct_stroke.png" caption="<span class="figure-number">Figure 1: 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)" >}}