Rover: add wing sail support

APMrover2/Log.cpp

@@ -138,14 +138,15 @@ void Rover::Log_Write_Sail()
         wind_speed_true = g2.windvane.get_true_wind_speed();
         wind_speed_apparent = g2.windvane.get_apparent_wind_speed();
     }
-    logger.Write("SAIL", "TimeUS,WindDirTrue,WindDirApp,WindSpdTrue,WindSpdApp,SailOut,VMG",
+    logger.Write("SAIL", "TimeUS,WndDrTru,WndDrApp,WndSpdTru,WndSpdApp,MainOut,WingOut,VMG",
-                        "shhnn%n", "F000000", "Qffffff",
+                        "shhnn%%n", "F0000000", "Qfffffff",
                         AP_HAL::micros64(),
                         (double)wind_dir_abs,
                         (double)wind_dir_rel,
                         (double)wind_speed_true,
                         (double)wind_speed_apparent,
                         (double)g2.motors.get_mainsail(),
+                        (double)g2.motors.get_wingsail(),
                         (double)g2.sailboat.get_VMG());
 }
 

APMrover2/mode.cpp

@@ -250,8 +250,10 @@ void Mode::calc_throttle(float target_speed, bool avoidance_enabled)
     if (rover.g2.sailboat.sail_enabled()) {
         // sailboats use special throttle and mainsail controller
         float mainsail_out = 0.0f;
-        rover.g2.sailboat.get_throttle_and_mainsail_out(target_speed, throttle_out, mainsail_out);
+        float wingsail_out = 0.0f;
+        rover.g2.sailboat.get_throttle_and_mainsail_out(target_speed, throttle_out, mainsail_out, wingsail_out);
         rover.g2.motors.set_mainsail(mainsail_out);
+        rover.g2.motors.set_wingsail(wingsail_out);
     } else {
         // call speed or stop controller
         if (is_zero(target_speed) && !rover.is_balancebot()) {
@@ -286,8 +288,9 @@ bool Mode::stop_vehicle()
         throttle_out = 100.0f * attitude_control.get_throttle_out_stop(g2.motors.limit.throttle_lower, g2.motors.limit.throttle_upper, g.speed_cruise, g.throttle_cruise * 0.01f, rover.G_Dt, stopped);
     }
 
-    // relax mainsail if present
+    // relax sails if present
     g2.motors.set_mainsail(100.0f);
+    g2.motors.set_wingsail(0.0f);
 
     // send to motor
     g2.motors.set_throttle(throttle_out);

APMrover2/mode_hold.cpp

@@ -12,6 +12,7 @@ void ModeHold::update()
 
     // relax mainsail
     g2.motors.set_mainsail(100.0f);
+    g2.motors.set_wingsail(0.0f);
 
     // hold position - stop motors and center steering
     g2.motors.set_throttle(throttle);

APMrover2/mode_manual.cpp

@@ -18,10 +18,12 @@ void ModeManual::update()
         rover.balancebot_pitch_control(desired_throttle);
     }
 
-    // set sailboat mainsail
+    // set sailboat sails
     float desired_mainsail;
-    g2.sailboat.get_pilot_desired_mainsail(desired_mainsail);
+    float desired_wingsail;
+    g2.sailboat.get_pilot_desired_mainsail(desired_mainsail, desired_wingsail);
     g2.motors.set_mainsail(desired_mainsail);
+    g2.motors.set_wingsail(desired_wingsail);
 
     // copy RC scaled inputs to outputs
     g2.motors.set_throttle(desired_throttle);

APMrover2/sailboat.cpp

@@ -10,14 +10,12 @@ To Do List
  - consider drag vs lift sailing differences, ie upwind sail is like wing, dead down wind sail is like parachute
  - max speed paramiter and controller, for mapping you may not want to go too fast
  - mavlink sailing messages
- - motor sailing, some boats may also have motor, we need to decide at what point we would be better of just motoring in low wind, or for a tight loiter, or to hit waypoint exactly, or if stuck head to wind, or to reverse...
  - smart decision making, ie tack on windshifts, what to do if stuck head to wind
  - some sailing codes track waves to try and 'surf' and to allow tacking on a flat bit, not sure if there is much gain to be had here
  - add some sort of pitch monitoring to prevent nose diving in heavy weather
  - pitch PID for hydrofoils
  - more advanced sail control, ie twist
  - independent sheeting for main and jib
- - wing type sails with 'elevator' control
  - tack on depth sounder info to stop sailing into shallow water on indirect sailing routes
  - add option to do proper tacks, ie tacking on flat spot in the waves, or only try once at a certain speed, or some better method than just changing the desired heading suddenly
 */
@@ -172,23 +170,26 @@ void Sailboat::init_rc_in()
 
 // decode pilot mainsail input and return in steer_out and throttle_out arguments
 // mainsail_out is in the range 0 to 100, defaults to 100 (fully relaxed) if no input configured
-void Sailboat::get_pilot_desired_mainsail(float &mainsail_out)
+void Sailboat::get_pilot_desired_mainsail(float &mainsail_out, float &wingsail_out)
 {
     // no RC input means mainsail is moved to trim
     if ((rover.failsafe.bits & FAILSAFE_EVENT_THROTTLE) || (channel_mainsail == nullptr)) {
         mainsail_out = 100.0f;
+        wingsail_out = 0.0f;
         return;
     }
     mainsail_out = constrain_float(channel_mainsail->get_control_in(), 0.0f, 100.0f);
+    wingsail_out = constrain_float(channel_mainsail->get_control_in(), -100.0f, 100.0f);
 }
 
 // calculate throttle and mainsail angle required to attain desired speed (in m/s)
 // returns true if successful, false if sailboats not enabled
-void Sailboat::get_throttle_and_mainsail_out(float desired_speed, float &throttle_out, float &mainsail_out)
+void Sailboat::get_throttle_and_mainsail_out(float desired_speed, float &throttle_out, float &mainsail_out, float &wingsail_out)
 {
     if (!sail_enabled()) {
         throttle_out = 0.0f;
         mainsail_out = 0.0f;
+        wingsail_out = 0.0f;
         return;
     }
 
@@ -207,11 +208,23 @@ void Sailboat::get_throttle_and_mainsail_out(float desired_speed, float &throttl
         throttle_out = 0.0f;
     }
 
+    // if we are motoring relax sails
+    if (motor_state == UseMotor::USE_MOTOR_ALWAYS) {
+        mainsail_out = 100.0f;
+        wingsail_out = 0.0f;
+        return;
+    }
+
+    // use PID controller to sheet out
+    float pid_offset = rover.g2.attitude_control.get_sail_out_from_heel(radians(sail_heel_angle_max), rover.G_Dt) * 100.0f;
+    pid_offset = constrain_float(pid_offset, 0.0f, 100.0f);
+
     //
     // mainsail control
     //
-    // if we are motoring or attempting to reverse relax the sail
+
-    if (motor_state == UseMotor::USE_MOTOR_ALWAYS || !is_positive(desired_speed)) {
+    // main sails cannot be used to reverse
+    if (!is_positive(desired_speed)) {
         mainsail_out = 100.0f;
     } else {
         // + is wind over starboard side, - is wind over port side, but as the sails are sheeted the same on each side it makes no difference so take abs
@@ -227,11 +240,26 @@ void Sailboat::get_throttle_and_mainsail_out(float desired_speed, float &throttl
         // linear interpolate mainsail value (0 to 100) from wind angle mainsail_angle
         float mainsail_base = linear_interpolate(0.0f, 100.0f, mainsail_angle,sail_angle_min,sail_angle_max);
 
-        // use PID controller to sheet out
-        const float pid_offset = rover.g2.attitude_control.get_sail_out_from_heel(radians(sail_heel_angle_max), rover.G_Dt) * 100.0f;
-
         mainsail_out = constrain_float((mainsail_base + pid_offset), 0.0f ,100.0f);
     }
+
+    //
+    // wingsail control
+    //
+
+    // wing sails auto trim, we only need to reduce power if we are tipping over
+    wingsail_out = 100.0f - pid_offset;
+
+    // wing sails must be trimmed for the correct tack
+    if (rover.g2.windvane.get_current_tack() == AP_WindVane::Sailboat_Tack::TACK_PORT) {
+        wingsail_out *= -1.0f;
+    }
+
+    // wing sails can be used to go backwards, probably not recommended though
+    if (!is_positive(desired_speed)) {
+        wingsail_out *= -1.0f;
+    }
+
 }
 
 // Velocity Made Good, this is the speed we are traveling towards the desired destination
@@ -333,7 +361,7 @@ float Sailboat::calc_heading(float desired_heading_cd)
     }
     bool should_tack = false;
 
-    // find witch tack we are on
+    // find which tack we are on
     const AP_WindVane::Sailboat_Tack current_tack = rover.g2.windvane.get_current_tack();
 
     // convert desired heading to radians

APMrover2/sailboat.h

@@ -37,10 +37,11 @@ public:
 
     // decode pilot mainsail input and return in steer_out and throttle_out arguments
     // mainsail_out is in the range 0 to 100, defaults to 100 (fully relaxed) if no input configured
-    void get_pilot_desired_mainsail(float &mainsail_out);
+    // wingsail_out is in the range -100 to 100, defaults to 0
+    void get_pilot_desired_mainsail(float &mainsail_out, float &wingsail_out);
 
     // calculate throttle and mainsail angle required to attain desired speed (in m/s)
-    void get_throttle_and_mainsail_out(float desired_speed, float &throttle_out, float &mainsail_out);
+    void get_throttle_and_mainsail_out(float desired_speed, float &throttle_out, float &mainsail_out, float &wingsail_out);
 
     // Velocity Made Good, this is the speed we are traveling towards the desired destination
     float get_VMG() const;