add px4 controller cmakelists

src/px4_connection/CMakeLists.txt

@@ -22,9 +22,16 @@ find_package(px4_ros_com REQUIRED)
 find_package(px4_msgs REQUIRED)
 
 add_executable(heartbeat src/heartbeat.cpp)
+add_executable(px4_controller src/px4_controller.cpp)
+
 target_include_directories(heartbeat PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:include>)
+
+target_include_directories(px4_controller PUBLIC
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  $<INSTALL_INTERFACE:include>)
+
 ament_target_dependencies(
   heartbeat
   rclcpp
@@ -32,7 +39,7 @@ ament_target_dependencies(
   px4_msgs
 )
 
-install(TARGETS heartbeat
+install(TARGETS heartbeat px4_controller
   DESTINATION lib/${PROJECT_NAME})
 
 if(BUILD_TESTING)

src/px4_connection/src/px4_controller.cpp

@@ -0,0 +1,74 @@
+/*
+
+We need to send attitude setpoints to be able to arm the drone:
+https://mavlink.io/en/messages/common.html#SET_ATTITUDE_TARGET
+We need attitude setpoints because we don't have a GPS:
+https://discuss.px4.io/t/cannot-arm-drone-with-companion-computer-arming-denied-manual-control-lost/31565/9
+
+*/
+
+#include <chrono>
+
+#include "rclcpp/rclcpp.hpp"
+
+#include <px4_msgs/msg/offboard_control_mode.hpp>
+#include <px4_msgs/msg/timesync.hpp>
+
+using namespace std::chrono_literals;
+
+class HeartBeat : public rclcpp::Node
+{
+public:
+    HeartBeat() : Node("setpoint_sender")
+    {
+        // create a publisher on the offboard control mode topic
+        offboard_control_mode_publisher_ = this->create_publisher<px4_msgs::msg::OffboardControlMode>("/fmu/in/offboard_control_mode", 10);
+        // create timer to send heartbeat messages (offboard control) every 100ms
+        timer_ = this->create_wall_timer(100ms, std::bind(&HeartBeat::send_heartbeat, this));
+        start_time = this->get_clock()->now().seconds();
+    }
+
+private:
+
+/**
+ * @brief Publish offboard control mode messages as a heartbeat.
+ *        Only the attitude is enabled, because that is how the drone will be controlled.
+ * 
+ */
+    void send_heartbeat()
+    {
+        // set message to enable attitude
+        auto msg = px4_msgs::msg::OffboardControlMode();
+        msg.position = false;
+        msg.velocity = false;
+        msg.acceleration = false;
+        msg.attitude = true;
+        msg.body_rate = false;
+        msg.actuator = false;
+
+        // get timestamp and publish message
+        msg.timestamp = this->get_clock()->now().nanoseconds() / 1000;
+        offboard_control_mode_publisher_->publish(msg);
+        RCLCPP_INFO(this->get_logger(), "sent offboard control mode message!");
+
+        // check if 5 seconds have elapsed
+        if (this->get_clock()->now().seconds() - start_time > 5)
+        {
+            RCLCPP_INFO(this->get_logger(), "5 seconds elapsed!");
+        }
+
+
+        
+    }
+    rclcpp::Publisher<px4_msgs::msg::OffboardControlMode>::SharedPtr offboard_control_mode_publisher_;
+    rclcpp::TimerBase::SharedPtr timer_;
+    double start_time;
+};
+
+int main(int argc, char *argv[])
+{
+    rclcpp::init(argc, argv);
+    rclcpp::spin(std::make_shared<HeartBeat>());
+    rclcpp::shutdown();
+    return 0;
+}