This PR adds up the possibility to correct the maximum reached tidal volume (TV) when operating in VCV mode in order to compensate for possible impairments due to flow losses.
Before
The TV setpoint is specified by the user but there wasn't any high-level closed-loop control guaranteeing that the estimated TV max was eventually attaining the setpoint.
What the PI controller ensures is that the flow-rate setpoint stemmed from the TV setpoint is actually achieved via feedback control. However, impairments in the circuit – essentially due to flow losses – can easily prevent from reaching the TV target.
Here's below an example:
The TV setpoint is 0.65 L, but we reached 0.63 L (due to flow losses).
Now
A simple integral action is further applied at the high-level closing the loop over the difference between the TV setpoint and the max TV estimate.
The new parameter TV_correction_gain regulates how fast the integral action shall react.
Gain = 0.1 (undercorrection)
Gain = 0.25 (default)
Gain = 0.5 (overcorrection)
Closing remarks
To make the high-level integral action work at its best, the estimation of TV max is now performed at each cycle instead of each 2 cycles.
The specification documents have been updated accordingly w/ revision 7.
This PR adds up the possibility to correct the maximum reached tidal volume (TV) when operating in VCV mode in order to compensate for possible impairments due to flow losses.
Before
The TV setpoint is specified by the user but there wasn't any high-level closed-loop control guaranteeing that the estimated
TV maxwas eventually attaining the setpoint.What the PI controller ensures is that the flow-rate setpoint stemmed from the TV setpoint is actually achieved via feedback control. However, impairments in the circuit – essentially due to flow losses – can easily prevent from reaching the TV target.
Here's below an example:
The TV setpoint is
0.65 L, but we reached0.63 L(due to flow losses).Now
A simple integral action is further applied at the high-level closing the loop over the difference between the TV setpoint and the max TV estimate.
The new parameter TV_correction_gain regulates how fast the integral action shall react.
Closing remarks
cc @maggia80 @simeonedussoni @marcoaccame