Joystick control dji psdk

Completed

Follow

Rinto

• March 06, 2023 08:46

Hi, I want to do thrust autonomous control.

- Is there any news on the mapping from value (0-100%) to thrust? Do you control RPM or forward a PWM to ESC internally?

- I try to do joystick control by first obtaining joystick authority. Then setting joystick mode: (vertical mode to 2=thrustcontrol, the rest to 0). When I do this, I see the drone making a small hop, but not maintaining the thrust. Should I send the joystick command at a certain rate to maintain a certain thrust?

- All the previous was done in DJI HITL SIM with PSDK 3.2 and a Matrice 300 RTK.

0

• 

  DJI Developer Support

  • March 06, 2023 11:20

  1、The flight controller will process the throttle parameters passed in from outside the O/PSDK to control the thrust. Unfortunately, the current flight controller does not provide a mapping from throttle parameters to thrust. Currently, the relationship between throttle thrust and ESC can be evaluated by subscribing to ESC data（TOPIC_ESC_DATA）. 2、The joystick needs to be sent continuously at a certain frequency, once the sending is stopped, the drone will stop moving.

  0

  Comment actions Permalink
• 

  Rinto

  • March 06, 2023 16:12

  Alright, thanks. Does this also work in HILSIM? I.e. does the rpm give realistic values when flying?

  0

  Comment actions Permalink
• 

  DJI Developer Support

  • March 07, 2023 02:21

  It can be used in the simulator, but the throttle value in the simulator and the actual flight may be different.

  0

  Comment actions Permalink
• 

  Rinto

  • March 07, 2023 07:46

  Alright. Thanks for your support.

  0

  Comment actions Permalink
• 

  Rinto

  • March 07, 2023 09:08

  I always get 180 RPM for the first 4 ESC's. Doesnt matter if flying, armed or not armed. I get 0 RPM for next 4 ESCS (which is realistic, since there are only four). Why is this? Code:
  
  

   

  if (DjiFcSubscription_SubscribeTopic(DJI_FC_SUBSCRIPTION_TOPIC_ESC_DATA, DJI_DATA_SUBSCRIPTION_TOPIC_50_HZ,

  escRPMCallback) != 0) {

  ROS_FATAL_STREAM("fcSubscribeTopic DJI_FC_SUBSCRIPTION_TOPIC_ESC_DATA failed\n");

  exit(1);

  }

   

  T_DjiReturnCode DjiTelemetry::escRPMCallback(const uint8_t* data, uint16_t, const T_DjiDataTimestamp* timestamp_fc) {

  T_DjiFcSubscriptionEscData esc_data_array = *((T_DjiFcSubscriptionEscData*)data);

  mb_msgs::ESCData msg;

  msg.stamp = mb_time_sync_.convertTimeRos(timestamp_fc->millisecond);

  for (int i = 0; i < kNumEscs; i++) {

  msg.speed.push_back(esc_data_array.esc[i].speed);

  std::cout<<"RPM = "<<static_cast<int>(esc_data_array.esc[i].speed)<<std::endl;

  }

  return isaac_interface_.executeFunction(AbstractFunction::PUBLISH_ESC_DATA, std::move(msg));

  }

  0

  Comment actions Permalink
• 

  DJI Developer Support

  • March 14, 2023 08:01

  Tested in the simulator, the value is 0 when the motor is not started, and 180 after the motor is started. Check again if the subscription data is correct. 

  0

  Comment actions Permalink
• 

  Barathwaja S

  • April 14, 2023 18:16

  DJI Developer Support,

  I'm also facing the same issue, like initially am getting 180 even when the drone is not armed or flying. Attaching below:

  

  0

  Comment actions Permalink

Please sign in to leave a comment.