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Open Modelica Thruster

System Description

This example describes a simple azimuth thruster model implemented in Open Modelica.

Model Description

Table 1: Input and output variables of the quarter truck fmus for connection

Name I/O Unit Description
thrusterOn I - Enable or disable thruster
DesiredFractionOfMaxThrust I [0…1] Desired thrust in percentage of max thrust
alpha I deg Desired azimuth
nu_r[1] I m/s Vessel velocity relative to current in surge
nu_r[2] I m/s Vessel velocity relative to current in sway
nu_r[3] I m/s Vessel velocity relative to current in heave
nu_r[4] I rad/s Vessel velocity relative to current in roll
nu_r[5] I rad/s Vessel velocity relative to current in pitch
nu_r[6] I rad/s Vessel velocity relative to current in yaw
power_available I W Power available to thruster
power O W Power consumed by thruster
tau_actual O N Thrust
tau_estimated O [0…1] Estimated thrust as a percentage of rated thrust

Simulation Results

The following plots show the model response given the setpoints in Table 2. Estimated thrust vs. produced thrust, as percentage of max thrust, is shown in Figure 1, power consumption in Figure 3 and produced thrust in Figure 2.

Table 2: Setpoints for thruster model

Name Value
thrusterOn True
DesiredFractionOfMaxThrust 0.5
alpha 0
nu_r[1] 0
nu_r[2] 0
nu_r[3] 0
nu_r[4] 0
nu_r[5] 0
nu_r[6] 0
power_available Inf  

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Figure 1: Desired vs. estimated thrust as a percentage of max thrust

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Figure 2: Produced thrust in N

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Figure 3: Power consumed in W