Hi friends!
I'm doing an experiment with APM and I need to know the order of magnitude of these parameters:
1. Noise of accelerometer and gyros.
2. Time delay between sending a waypoint to autopilot till the autopilot recieves it.
3. Lag of regular rotors. (the time it takes for the rotor to reach 63% of the desired speed) for example 0.1 second or higher
or can you introduce me somebody or resources to find out.
Any help is appreciated.
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Replies
Thanks Vinnie for your complete answer. I have plans to change my platform to Pixhawk too.
Sorry to ask again, but Can you explain me, these :
1. If I want to model noise of accels and gyros with white noise, how much variance Should I take? 0.4 G for accels and 1 rad/s for gayros is OK?
2. I think in "Followe me" mode the waypoints get uploaded continuously. Is this feature practical?
3. I want to know the lag of only brushless motors. They have lag because of mechanical and electrical issues.
Thank you.
First, it had already been mentioned in many places, but I will mention this again. The APM board had already passed it's end of life and is currently posted on the 3D Robotics site the APM is no longer supported by current firmware. So you should take cautions doing research with the APM.
1. Noise of accelerometer and gyroscopes are filtered by the Ardupilot logic. The threshold for noise from vibration is 0.3G on X and Y axis and 0.5G on Z axis.
2. If you are talking about autonomous missions, waypoints must be uploaded prior to the start of auto missions. You cannot change waypoint in the middle so the time delay is not a question.
3. This is a question depending on the Radio transmitter and receiver you are using in addition to the wiring and type of ESC you are using in your build as well as interference. So there is no answer for this.
Current Copter firmware is 3.2.1. Mission Planner loads 3.2.1 to an APM despite there being a message saying that it has been "retired" - so surely APM must be supported?
I don't understand why you would argue about this. Here is the link to the store for 3DR on the APM and please read. APM 2.6 on 3D Robotics store
APM is only supported up to 3.2 firmware. Higher firmware can still be loaded onto the APM for use on rovers and planes. Mission Planner is not coded to stop you from loading current firmware; however, APM will take 3.2.1 with issues for multirotors. Many have experienced pulsation problems and there is no fix for it. If you can get it to fly fine, by all means use it, but it there is no more fixes unless you are tech savvy enough to correct the code yourself. It is already stated there for 3.3 and up, you must use Pixhawk. I have requested to have the software development forked to keep APM alive, but there is no plan for that at the moment. You can still safely fly multirotors with APM using firmware 3.1.5 or 3.2 if you know what you are doing, but do not expect any future updates.
I'm not arguing about anything, merely trying to point out the fact that MP encourages users to load a version of firmware that you say may cause issues without giving a warning.
MP says it will load the latest version that will run on my board, so me, and any logical other person, would assume that 3.2.1 is OK to use because that's what MP then loads. Not every user of these products keeps themselves updated with the intricacies of the firmware lifecycle, assuming instead that the software that manages the system will do the important things for them.