Advanced tuning setup

Pixhawk
1

Dear all @Jaeyoung-Lim
I want to PID tuning using ‘Advanced Tuning Setup’ of Qgroundcontrol for quadcopter with pixhawk4.

First, I tested the Pixhawk 4 by connecting the PC and usb cable, and confirmed that the reaction is good as shown below.

Cable_Connection
Cable_Connection1487×745 115 KB

However, when I tested by telemetry(Holybro) connecting the pixhawk4, the response of Roll Rate does not respond and the response cycle is very slow as shown in the figure below.

telemetry_Connection
telemetry_Connection1494×769 113 KB

Is this a telemetry problem that I use?
Has anyone ever tuned using Advanced Tuning Setup like me?

2

What is the bandwidth of your telemetry module? Telemetry modules in general do not have high bandwidth so seems like the difference is in the bandwidth

3

We use ‘Holybro’ 433MHz telemetry and it is set 57600 baud rate.

Even though we have set 115200 baud rate, it is same response.

Is there a problem with other things, not baud rate and frequency rate?

I think, this ‘advanced tuning setup’ is very useful because it does not need SD memory card for checking flight analysis when PID tuning

I wonder that others use it well.

4

Baudrate 115200 is already quite low compared to your serial connection over USB. Also communication using FSK on 433MHz has extremely low bandwidth,

You are using the wrong communication medium for what you are trying to achieve

5

So, could you recommend another alternative?

Even I have tried RFD 900MHz radio,it’s also same.

Or Wifi telemetry is suitable?

6

@jongbeom.her Yes, or even a serial link to the mission computer which routes mavlink to wifi is sufficient for this. (I recall your system has a mission computer onboard)

900MHz modules still have quite low bandwidth as it is designed for long range low bandwidth communications. Have you checked the data rate of your 900MHz telemetry module?

7

900MHz telemetry module is also 115200 max baudrate, I think almost RF telemetry has same rate.

So, next step I will try Wifi module.
Actually we don’t use onboard computer to PID tune.
I have a plane, Pixhawk + ESP8266 Wifi ↔ Laptop PC for tuning.

8

I have question one more thing.

As you said, we use onboard computer for flight mission.
So, I have a idea to make a advance tuning setup tool by self using ros rqt graph.
We already get attitude and rate response by ros message.
However, we can get a command attitude and rate by ros message from PX4 to make tuning graph like above picture?

9

@jongbeom.her baudrate is not equivalent with bandwidth, and for your application 115200 is not high enough IMHO.

Baudrates are the rate your data moves through the UART interface. This doesn’t mean that you will have data throughput through the communication medium (AFSK for 433MHz Sik Radio modules)

I didn’t understand your second question properly. Are you asking if it is possible to create the same graph through rqt? of course

10

115200 baudrate is between Pixhawk and module itself. The actual over-the-air speed is much lower and depends on the framing and ECC.

11

Thank you, I just have checked rqt graph for PID tuning.

Further more, can I change the gain parameter setting with ROS totic without QGC?

I want to develop PID tuning tool that does not use QGC at all.

12

@jongbeom.her yes you can

13

Thank you for your reply