I have several points on which I seek clarification or confirmation regarding the test conditions during the assessment of the ROV’s maximum specifications as stated in the datasheet / technical reference:
Bollard Thrust:
Forward (45°): 9 kgf
Vertical: 7 kgf
Lateral (45°): 9 kgf
Here are my questions:
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Operating Voltage and Current Drawn: Could you specify the operating voltage and the current drawn by the ROV when it was generating its maximum force?
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Is there time series data of the bollard tests including the force, battery voltage, current and esc control signals that could be shared?
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Specifically, I’m interested in the voltage drop during your bollard thrust measurements.
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The vertical bollard thrust scenario was also discussed in the “Thruster Force” topic, mentioning
Assuming a fully charged battery at 16.8 v/ 4.2 v per cell, under a 50 A load the cell voltage could
be expected to drop to about 3.8 v, or ~15.2 v total. -
From own measurements I can confirm that voltage drop can be around 2 V @ 50 A and 3V @ 75 A.
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Battery Voltage Confirmation: Can you confirm that the battery used was initially charged to a voltage of 16.8 V for these tests?
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Test Environment: Was the BlueROV tested in a tank fully submerged, similar to the single thruster tests, as detailed in the
T200-Public-Performance-Data-10-20V-September-2019.xlsx
and shown in this article thruster test stand ?- And/or was a different, alternative setup used, such as an open-water experiment in a sea or lake, involving the actual pulling of a steel rope?
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Measurement Uncertainty: What was the uncertainty (standard deviation) associated with the force measurements?