Different input for the thrusters

kamilshamsi2695 · October 8, 2018, 9:03am

Is it possible to have different servo values for all the thrusters? Basically what we want to do is to grab something with the grasper of the ROV which is causing the ROV to tilt forward. If we are able to have different inputs then we can use the imu to identify that the ROV is tilting forward and increase the front thruster servo value to prevent this problem.

tciii · October 8, 2018, 1:55pm

@kamilshamsi2695,

Have you already tried the “Stablize” Mode?

Regards,
TCIII AVD

kamilshamsi2695 · October 9, 2018, 3:24am

Nevermind, I didn’t realize that the rov does not have seperate thrusters for the front and the back so what I wanted to do is not possible.

Btw, is the code used for the ‘stabilize’ mode and ‘depth hold mode’ accessible to the user? I wanted to see exactly how it is implemented

patrickelectric · October 9, 2018, 11:53am

Hi,

The BlueROV2 runs ArduSub, an open-source solution for remotely operated underwater vehicles (ROVs) and autonomous underwater vehicles (AUVs). ArduSub is a part of the ArduPilot project, and was originally derived from the ArduCopter code. You can check more about it here.
The source code of the project is in GitHub.

You can check our last release for ardusub stabilize mode code here:

github.com

ArduPilot/ardupilot/blob/Sub-3.5/ArduSub/control_stabilize.cpp#L15


      
          {
              // set target altitude to zero for reporting
              pos_control.set_alt_target(0);
              last_pilot_heading = ahrs.yaw_sensor;
          
          
    return true;
          }
          
          
// stabilize_run - runs the main stabilize controller
          // should be called at 100hz or more
          void Sub::stabilize_run()
          {
              uint32_t tnow = AP_HAL::millis();
              float target_roll, target_pitch;
              float target_yaw_rate;
          
          
    // if not armed set throttle to zero and exit immediately
              if (!motors.armed()) {
                  motors.set_desired_spool_state(AP_Motors::DESIRED_SPIN_WHEN_ARMED);
                  attitude_control.set_throttle_out_unstabilized(0,true,g.throttle_filt);
                  last_pilot_heading = ahrs.yaw_sensor;

And depth hold here:

github.com

ArduPilot/ardupilot/blob/Sub-3.5/ArduSub/control_althold.cpp#L33


      
              pos_control.set_alt_target(inertial_nav.get_altitude());
              pos_control.set_desired_velocity_z(inertial_nav.get_velocity_z());
          
          
    last_pilot_heading = ahrs.yaw_sensor;
          
          
    return true;
          }
          
          
// althold_run - runs the althold controller
          // should be called at 100hz or more
          void Sub::althold_run()
          {
              uint32_t tnow = AP_HAL::millis();
          
          
    // initialize vertical speeds and acceleration
              pos_control.set_speed_z(-g.pilot_velocity_z_max, g.pilot_velocity_z_max);
              pos_control.set_accel_z(g.pilot_accel_z);
          
          
    if (!motors.armed()) {
                  motors.set_desired_spool_state(AP_Motors::DESIRED_SPIN_WHEN_ARMED);
                  // Sub vehicles do not stabilize roll/pitch/yaw when not auto-armed (i.e. on the ground, pilot has never raised throttle)

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