# Not able to set actuator controls for fixed wing in SITL **URL:** \ **Category:** Uncategorized\ **Created:** [June 14, 2021, 12:44pm UTC](https://discuss.px4.io/t/not-able-to-set-actuator-controls-for-fixed-wing-in-sitl/22824 "2021-06-14T12:44:34Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![raghunandan\_V](https://discuss.px4.io/user_avatar/discuss.px4.io/raghunandan_v/32/7727_2.png) [@raghunandan\_V](https://discuss.px4.io/u/raghunandan_V)\ **Post date:** [June 14, 2021, 12:44pm UTC](https://discuss.px4.io/t/not-able-to-set-actuator-controls-for-fixed-wing-in-sitl/22824/1 "2021-06-14T12:44:34Z")
Hey, I am trying to send the actuator commands directly over `/mavros/actuator_control` in offboard mode but when I send the commands the Px4 is forced to switch back to position control mode and doesn’t come back to offboard mode and the plane doesnt fly. These are the steps I followed: 1. disable lockstep simulation 2. started px4 sitl: > make px4\_sitl gazebo\_plane 1. started mavros: ```auto roslaunch mavros px4.launch fcu_url:="udp://:14540@127.0.0.1:14557" ``` 1. ran this code: ```auto #include #include #include #include #include #include mavros_msgs::State current_state; void state_cb(const mavros_msgs::State::ConstPtr& msg){ current_state = *msg; } int main(int argc, char **argv) { ros::init(argc, argv, "offb_node"); ros::NodeHandle nh; ros::Subscriber state_sub = nh.subscribe ("mavros/state", 10, state_cb); // ros::Publisher local_pos_pub = nh.advertise // ("mavros/setpoint_position/local", 10); ros::Publisher act_pub = nh.advertise ("mavros/actuator_control", 10); ros::ServiceClient arming_client = nh.serviceClient ("mavros/cmd/arming"); ros::ServiceClient set_mode_client = nh.serviceClient ("mavros/set_mode"); //the setpoint publishing rate MUST be faster than 2Hz ros::Rate rate(50.0); // wait for FCU connection while(ros::ok() && !current_state.connected){ ros::spinOnce(); rate.sleep(); } geometry_msgs::PoseStamped pose; pose.pose.position.x = 0; pose.pose.position.y = 20; pose.pose.position.z = 20; mavros_msgs::ActuatorControl setpoint; setpoint.header.stamp = ros::Time::now(); setpoint.group_mix = 0; setpoint.controls[0] = 0; setpoint.controls[1] = 0; setpoint.controls[2] = 0; setpoint.controls[3] = 1; setpoint.controls[4] = 0; setpoint.controls[5] = 0; setpoint.controls[6] = 0; setpoint.controls[7] = 0; //send a few setpoints before starting for(int i = 20; ros::ok() && i > 0; --i){ // local_pos_pub.publish(pose); act_pub.publish(setpoint); ros::spinOnce(); rate.sleep(); } mavros_msgs::SetMode offb_set_mode; offb_set_mode.request.custom_mode = "OFFBOARD"; mavros_msgs::CommandBool arm_cmd; arm_cmd.request.value = true; ros::Time last_request = ros::Time::now(); ros::Time last_request_arm = ros::Time::now(); while(ros::ok()){ // act_pub.publish(setpoint); if( current_state.mode != "OFFBOARD" && (ros::Time::now() - last_request > ros::Duration(0.5))){ if( set_mode_client.call(offb_set_mode) && offb_set_mode.response.mode_sent){ ROS_INFO("Offboard enabled"); } last_request = ros::Time::now(); } if( !current_state.armed && (ros::Time::now() - last_request_arm > ros::Duration(1))){ if( arming_client.call(arm_cmd) && arm_cmd.response.success){ ROS_INFO("Vehicle armed"); } last_request_arm = ros::Time::now(); } // local_pos_pub.publish(pose); act_pub.publish(setpoint); // local_pos_pub.publish(pose); ros::spinOnce(); rate.sleep(); } return 0; } ``` Not sure what I am doing wrong. Any help will be appreciated. Thanks in advance ---
**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\ **Post date:** [September 21, 2023, 11:26pm UTC](https://discuss.px4.io/t/not-able-to-set-actuator-controls-for-fixed-wing-in-sitl/22824/2 "2023-09-21T23:26:01Z")
I think PX4 doesn’t support actuator controls at the current version. > > > \## Describe the bug > We are a team of researchers and need direct access to the …actuators when working with Rovers/Boats, but this feature does not seem to be working. > > We are using Mavsdk to send values between -1 and 1 to the actuators. > > I checked and can confirm that the values are being received in the vehicle and being correctly published to the topic with ORB\_ID = actuator\_controls\_0 (as well as actuator\_controls\_1). > > !\[Screenshot from 2023-02-02 18-21-51\](https://user-images.githubusercontent.com/69345264/216415339-ac8ff1e4-ae02-4f82-a6c1-5d3fdd4aa022.png) > > > Therefore values are being published but no response can be seen. > > This is being handled by the following function: > !\[void MavlinkReceiver::handle\_message\_set\_actuator\_control\_target(mavlink\_message\_t \*msg)\](https://github.com/PX4/PX4-Autopilot/blob/46a12a09bf11c8cbafc5ad905996645b4fe1a9df/src/modules/mavlink/mavlink\_receiver.cpp#L1259) > > I don't mind correcting the error and creating a PR, but I would like to know what is the best way to fix this issue. > I think that the problem is that 'actuator\_controls\_0' is not being used and has been replaced by 'vehicle\_thrust\_setpoint' and 'vehicle\_torque\_setpoint' as mentioned in issue #20981, but I might be wrong. I have also encountered some other interesting topics namely: 'ORB\_ID(actuator\_motors)' and 'ORB\_ID(actuator\_servos)' that might be key to solving this problem. > > I would appreciate it if someone could help me understand the issue. And if I am correct in the above statement, what would be the mapping from control groups to 'some other' topic? > > \## To Reproduce > Steps to reproduce the behavior: > 1. Start PX4 SITL Rover Gazebo Simulation (tested both v1.13.2 and v1.14.0-beta1) (lockstep must be disabled -\> check https://docs.px4.io/main/en/simulation/ where it shows how to disable it) > 2. Open QGC and wait for connection > 3. Test the following python script \[off\_board\_actuator.zip\](https://github.com/PX4/PX4-Autopilot/files/10572126/off\_board\_actuator.zip) > 4. Check on console uORB topics actuator\_controls\_0 as well as actuator\_controls\_1 (using command: listener actuator\_controls\_0 in the terminal where px4\_sitl is running) where we can see that the correct values are being published. > 5. No actuators move and we can see that nothing is being published to the actuators (check qgroundcontrol SERVO\_OUTPUT\_RAW, ... in the mavlink inspector) > > !\[Screenshot from 2023-02-02 18-22-26\](https://user-images.githubusercontent.com/69345264/216415251-eec15947-6d7b-4d4d-9e71-8aa049a747b5.png) > > > > > > \## Expected behavior > We expect to be able to control the actuators directly. > > \## Log File > https://logs.px4.io/plot\_app?log=533206ce-1228-43f7-8797-027ade652ffa > > Thank you for your help.