AP_LandingGear: set pwm only when set_position called

Also simplify interface and internal state

libraries/AP_LandingGear/AP_LandingGear.cpp

@@ -29,10 +29,24 @@ const AP_Param::GroupInfo AP_LandingGear::var_info[] = {
     AP_GROUPEND
 };
 
-/// enable - enable or disable land gear retraction
+/// set landing gear position to retract, deploy or deploy-and-keep-deployed
-void AP_LandingGear::enable(bool on_off)
+void AP_LandingGear::set_position(LandingGearCommand cmd)
 {
-    _retract_enabled = on_off;
+    switch (cmd) {
+        case LandingGear_Retract:
+            if (!_deploy_lock) {
+                retract();
+            }
+            break;
+        case LandingGear_Deploy:
+            deploy();
+            _deploy_lock = false;
+            break;
+        case LandingGear_Deploy_And_Keep_Deployed:
+            deploy();
+            _deploy_lock = true;
+            break;
+    }
 }
 
 /// deploy - deploy landing gear
@@ -42,43 +56,15 @@ void AP_LandingGear::deploy()
     SRV_Channels::set_output_pwm(SRV_Channel::k_landing_gear_control, _servo_deploy_pwm);
 
     // set deployed flag
-    _deployed = true;    
+    _deployed = true;
 }
 
 /// retract - retract landing gear
 void AP_LandingGear::retract()
-{    
+{
     // set servo PWM to retracted position
     SRV_Channels::set_output_pwm(SRV_Channel::k_landing_gear_control, _servo_retract_pwm);
 
     // reset deployed flag
-    _deployed = false;   
+    _deployed = false;
-}
-
-/// update - should be called at 10hz
-void AP_LandingGear::update()
-{
-    // if there is a force deploy active, disable retraction, then reset force deploy to consume it
-    // gear will be deployed automatically because _retract_enabled is false.
-    // this will disable retract switch until it is cycled through deploy position
-    if (_force_deploy){
-            enable(false);
-            force_deploy(false);
-        }
-
-    if (!_retract_enabled) {
-        // force deployment if retract is not enabled
-        deploy();
-        // retract is disabled until switch is placed into deploy position to prevent accidental retraction on bootup if switch was left in retract position
-        enable(_command_mode == LandingGear_Deploy);
-        return;
-    }
-
-    if (_command_mode == LandingGear_Deploy){
-        deploy();
-    }
-
-    if (_command_mode == LandingGear_Retract){
-        retract();
-    }    
 }

libraries/AP_LandingGear/AP_LandingGear.h

@@ -8,59 +8,43 @@
 #define AP_LANDINGGEAR_SERVO_RETRACT_PWM_DEFAULT    1250    // default PWM value to move servo to when landing gear is up
 #define AP_LANDINGGEAR_SERVO_DEPLOY_PWM_DEFAULT     1750    // default PWM value to move servo to when landing gear is down
 
-// Gear command modes
-enum LandingGearCommandMode {
-    LandingGear_Deploy,
-    LandingGear_Auto,
-    LandingGear_Retract
-};
-
 /// @class	AP_LandingGear
 /// @brief	Class managing the control of landing gear
 class AP_LandingGear {
 
 public:
 
+    // Gear command modes
+    enum LandingGearCommand {
+        LandingGear_Retract,
+        LandingGear_Deploy,
+        LandingGear_Deploy_And_Keep_Deployed,
+    };
+
     /// Constructor
-    AP_LandingGear() :
+    AP_LandingGear()
-        _retract_enabled(false),
-        _deployed(false),
-        _force_deploy(false),
-        _command_mode(LandingGear_Deploy)
     {
         // setup parameter defaults
         AP_Param::setup_object_defaults(this, var_info);
     }
 
-    /// deployed - returns true if the landing gear is deployed
+    /// returns true if the landing gear is deployed
     bool deployed() const { return _deployed; }
 
-    /// update - should be called at 10hz
+    /// set landing gear position to retract, deploy or deploy-and-keep-deployed
-    void update();
+    void set_position(LandingGearCommand cmd);
-
-    /// set_cmd_mode - set command mode to deploy, auto or retract
-    void set_cmd_mode(LandingGearCommandMode cmd) { _command_mode = cmd; }
-
-    /// force_deploy - set to true to force gear to deploy
-    void force_deploy(bool force) { _force_deploy = force;}
 
     static const struct AP_Param::GroupInfo        var_info[];
 
 private:
 
-    bool     _retract_enabled;          // true if landing gear retraction is enabled
-
     // Parameters
     AP_Int16    _servo_retract_pwm;     // PWM value to move servo to when gear is retracted
     AP_Int16    _servo_deploy_pwm;      // PWM value to move servo to when gear is deployed
 
     // internal variables
     bool        _deployed;              // true if the landing gear has been deployed, initialized false
-    bool        _force_deploy;          // used by main code to force landing gear to deploy, such as in Land mode
+    bool        _deploy_lock;           // used to force landing gear to remain deployed until another regular Deploy command is received to reduce accidental retraction
-    LandingGearCommandMode  _command_mode;  // pilots commanded control mode: Manual Deploy, Auto, or Manual Retract
-    
-    /// enable - enable landing gear retraction
-    void enable(bool on_off);
     
     /// retract - retract landing gear
     void retract();