Parameters Setting
You can use MatMav to modify any parameters on the Pixhawk online. You will need to know the parameter name as written in Qgroundcontrol. Currently, there is no function that reads a parameter value from the Pixhawk.
NOTE: Not all parameters can be modified online. An example is the MAVLINK ID, which requires restarting the Pixhawk. PID gains and many others can be modified online.
To set a certain parameter, use the setParamter() function.
sysID=1;
value=1.0;
% here we are setting the parameter named 'MPC_XY_P'
obj.setParamter(sysID,0,'MPC_XY_P',value);
You can check back that the parameter is written in Qgroundcontrol.