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

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

Figure 2: Produced thrust in N

Figure 3: Power consumed in W