For some time now, I’ve been using the “Initial Tune Parameters” feature in Mission Planner.
Today I realized that this feature leaves whatever PID values you have unchanged. So if you’re using a flight controller that was previously used in a different vehicle, the initial parameter settings may be unpredictable.
The only place I’ve found that will set all the initial parameters, including PID values, back to default is here:
The “Initial Tune Parameter” routine plainly shows the parameters it’s changing. But for the uninitiated, it’s not clear that this set of parameters may be very incomplete.
For a new flight controller, this isn’t a problem. But it would be helpful if there were instructions how to set parameters properly on a flight controller taken from another vehicle.
I don’t think we should expect this feature to reset all other parameters to default. By the time we get to this step, we may have already configured hardware options and such. It would piss me off royally if setting some tuning parameters wiped my autopilot of other settings!
But for basic tuning, we need to have a reasonable starting point.
For example, in the tuning guide it states that if there oscillations on the first test hover flights, to reduce the pitch and roll PIDs by 50%. And again if necessary.
I believe this statement assumes that the builder has started with the “default” PIDs.
I don’t recall ever reading that page. Not surprising - it’s not really possible to read the wiki cover to cover and be able to recall which pages might be important for different activities.
The initial tuning guide assumes that the parameters start with some “default” PIDs. That’s why it says to reduce PIDs by 50% if on initial test hovers there are oscillations. (and then to reduce them in half again if necessary)
The common scenario is that a copter is changed - new props, different battery, new payload, etc. In such cases it makes sense to just start the tuning process over again from the beginning.
But without having “default” PIDs to go back to - this isn’t really possible.
People with lots of tuning experience might be able to check PIDs for reasonableness. But for those without such experience, PIDs, filters and acceleration parameters are just numbers.
But as I mention in my comment below - this doesn’t account for when there’s some sort of change to the vehicle (props, battery, payload, etc.) that might make it necessary to start the tuning process again from the beginning.
While I have seen the page before I just Googled “arducopter reset to default” to find it again.
In fact I saw this page recently after seeing a YouTube video from one of the prominent talking-heads not giving the best advice about this very topic. So, of course I said so in the comment section and linked to the Wiki page. My comment was deleted.
So I’m wondering if the value of these 19 parameters could be placed in a .param file with values from the “default settings” option (or a new installation) and that be used as tuning reset to default.
The “Step 2” of the Initial Tune Parameters in Mission Planner has this:
So perhaps PSC_ACCZ_P and PSC_ACCZ_I would also need to be set to “default settings.”
Since these two parameters are not adjusted by autotune, I’m wondering when and where they are ever changed except for this step of the Initial Tune Parameters.
The question is are there other tune related parameters that Ardupilot changes in the course of normal operation that might need to be reset as well.
I’ve found a method that will get rid of the problem of resetting old parameters. Before installing the new firmware, I erase the flash memory as described in this link and download the current firmware. When Problems Arise — Plane documentation . Then I study a new list of parameters that correspond to the selected firmware, and write down the settings parameters taking into account the changes. This process is long, but it is very effective. However, many changes have been made since firmware 4.5.0 and there will be changes to 4.6.x in the future. Plane 4.5 release . No automatic rescaling of parameters when overwriting to a new firmware will replace the process of learning new features of the ardupilot.
