Docs update; Unify signedness

docs/Cli.md

@@ -243,12 +243,15 @@ Re-apply any new defaults as desired.
 |  servo_pwm_rate  | 50 | Output frequency (in Hz) servo pins. Default is 50Hz. When using tricopters or gimbal with digital servo, this rate can be increased. Max of 498Hz (for 500Hz pwm period), and min of 50Hz. Most digital servos will support for example 330Hz. |
 |  failsafe_delay  | 5 | Time in deciseconds to wait before activating failsafe when signal is lost. See [Failsafe documentation](Failsafe.md#failsafe_delay). |
 |  failsafe_recovery_delay  | 5 | Time in deciseconds to wait before aborting failsafe when signal is recovered. See [Failsafe documentation](Failsafe.md#failsafe_recovery_delay). |
-|  failsafe_off_delay  | 200 | Time in deciseconds to wait before turning off motors when failsafe is activated. See [Failsafe documentation](Failsafe.md#failsafe_off_delay). |
+|  failsafe_off_delay  | 200 | Time in deciseconds to wait before turning off motors when failsafe is activated. 0 = No timeout. See [Failsafe documentation](Failsafe.md#failsafe_off_delay). |
 |  failsafe_throttle  | 1000 | Throttle level used for landing when failsafe is enabled. See [Failsafe documentation](Failsafe.md#failsafe_throttle). |
 |  failsafe_kill_switch  | OFF | Set to ON to use an AUX channel as a failsafe kill switch. |
-|  failsafe_throttle_low_delay  | 100 | Activate failsafe when throttle is low and no RX data has been received since this value, in 10th of seconds |
+|  failsafe_throttle_low_delay  | 100 | If failsafe activated when throttle is low for this much time - bypass failsafe and disarm, in 10th of seconds. 0 = No timeout |
 |  failsafe_procedure  | SET-THR | What failsafe procedure to initiate in Stage 2. See [Failsafe documentation](Failsafe.md#failsafe_throttle). |
 |  failsafe_stick_threshold  | 0 | Threshold for stick motion to consider failsafe condition resolved. If non-zero failsafe won't clear even if RC link is restored - you have to move sticks to exit failsafe. |
+|  failsafe_fw_roll_angle  | -200 | Amount of banking when `SET-THR` failsafe is active on a fixed-wing machine. In 1/10 deg (deci-degrees). Negative values = left roll |
+|  failsafe_fw_pitch_angle  | 100 | Amount of dive/climb when `SET-THR` failsafe is active on a fixed-wing machine. In 1/10 deg (deci-degrees). Negative values = climb |
+|  failsafe_fw_yaw_rate  | 45 | Requested yaw rate to execute when `SET-THR` failsafe is active on a fixed-wing machine. In deg/s. Negative values = left turn |
 |  rx_min_usec  | 885 | Defines the shortest pulse width value used when ensuring the channel value is valid. If the receiver gives a pulse value lower than this value then the channel will be marked as bad and will default to the value of mid_rc. |
 |  rx_max_usec  | 2115 | Defines the longest pulse width value used when ensuring the channel value is valid. If the receiver gives a pulse value higher than this value then the channel will be marked as bad and will default to the value of mid_rc. |
 |  rx_nosignal_throttle  | HOLD | Defines behavior of throttle channel after signal loss is detected and until `failsafe_procedure` kicks in. Possible values - `HOLD` and `DROP`. |

docs/Failsafe.md

@@ -86,7 +86,7 @@ Guard time for failsafe de-activation after signal is recovered.  This is the am
 
 ### `failsafe_off_delay`
 
-Delay after failsafe activates before motors finally turn off.  This is the amount of time 'failsafe_throttle' is active.  If you fly at higher altitudes you may need more time to descend safely.
+Delay after failsafe activates before motors finally turn off.  This is the amount of time 'failsafe_throttle' is active.  If you fly at higher altitudes you may need more time to descend safely. Set to zero to keep `failsafe_throttle` active indefinitely. Has no effect when `failsafe_procedure = RTH`
 
 ### `failsafe_throttle`
 
@@ -98,14 +98,14 @@ Configure the rc switched failsafe action: the same action as when the rc link i
 
 ### `failsafe_throttle_low_delay`
 
-Time throttle level must have been below 'min_throttle' to _only disarm_ instead of _full failsafe procedure_.
+Time throttle level must have been below 'min_throttle' to _only disarm_ instead of _full failsafe procedure_. Set to zero to disable.
 
 Use standard RX usec values.  See Rx documentation.
 
 ### `failsafe_procedure`
 
-* __Drop:__ Just kill the motors and disarm (crash the craft).
+* __DROP:__ Just kill the motors and disarm (crash the craft).
-* __Land:__ Enable an auto-level mode, center the flight sticks and set the throttle to a predefined value (`failsafe_throttle`) for a predefined time (`failsafe_off_delay`). This should allow the craft to come to a safer landing.
+* __SET-THR:__ Enable an auto-level mode (for multirotor) or enter preconfigured roll/pitch/yaw spiral down (for airplanes) and set the throttle to a predefined value (`failsafe_throttle`) for a predefined time (`failsafe_off_delay`). This should allow the craft to come to a safer landing.
 * __RTH:__ Attempt to return and land the drone at the point of launch. GPS and Barometer required for proper operation. If this more is selected and GPS is not available - the drone will be landed immediately.
 * __NONE:__ Do nothing. This is least safe method but it could be used to execute WP missions outside of RC radio coverage.
 
@@ -117,6 +117,20 @@ When this is set to a non-zero value - failsafe won't clear even if RC link is r
 
 One use-case is Failsafe-RTH. When on the edge of radio coverage you may end up entering and exiting RTH if radio link is sporadic - happens a lot with long-range pilots. Setting `failsafe_stick_threshold` to a certain value (i.e. 100) RTH will be initiated on first signal loss and will continue as long as pilots want it to continue. When RC link is solid (based on RSSI etc) pilot will move sticks and regain control.
 
+### `failsafe_fw_roll_angle`
+
+When `SET-THR` failsafe is executed on a fixed-wing craft it's not safe to keep it level - airplane can glide for long distances. 
+
+This parameter defines amount of roll angle (in 1/10 deg units) to execute on failsafe. Negative = LEFT
+
+### `failsafe_fw_pitch_angle`
+
+This parameter defines amount of pitch angle (in 1/10 deg units) to execute on `SET-THR` failsafe for an airplane. Negative = CLIMB
+
+### `failsafe_fw_yaw_rate`
+
+This parameter defines amount of yaw rate (in deg per second units) to execute on `SET-THR` failsafe for an airplane. Negative = LEFT
+
 ### `rx_min_usec`
 
 The lowest channel value considered valid.  e.g. PWM/PPM pulse length

src/main/flight/failsafe.c

@@ -72,7 +72,7 @@ PG_RESET_TEMPLATE(failsafeConfig_t, failsafeConfig,
     .failsafe_procedure = 0,            // default full failsafe procedure is 0: auto-landing, 1: drop, 2 : RTH
     .failsafe_fw_roll_angle = -200,     // 20 deg left
     .failsafe_fw_pitch_angle = 100,     // 10 deg dive (yes, positive means dive)
-    .failsafe_fw_yaw_rate = 45,         // 45 deg/s left yaw (left is positive, 4s for full turn)
+    .failsafe_fw_yaw_rate = -45,        // 45 deg/s left yaw (left is negative, 4s for full turn)
     .failsafe_stick_motion_threshold = 50,
 );
 
@@ -230,7 +230,7 @@ void failsafeApplyControlInput(void)
     if (STATE(FIXED_WING)) {
         autoRcCommand[ROLL] = pidAngleToRcCommand(failsafeConfig()->failsafe_fw_roll_angle, pidProfile()->max_angle_inclination[FD_ROLL]);
         autoRcCommand[PITCH] = pidAngleToRcCommand(failsafeConfig()->failsafe_fw_pitch_angle, pidProfile()->max_angle_inclination[FD_PITCH]);
-        autoRcCommand[YAW] = pidRateToRcCommand(failsafeConfig()->failsafe_fw_yaw_rate, currentControlRateProfile->rates[FD_YAW]);
+        autoRcCommand[YAW] = -pidRateToRcCommand(failsafeConfig()->failsafe_fw_yaw_rate, currentControlRateProfile->rates[FD_YAW]);
         autoRcCommand[THROTTLE] = failsafeConfig()->failsafe_throttle;
     }
     else {

src/main/navigation/navigation_fixedwing.c

@@ -483,7 +483,7 @@ void applyFixedWingEmergencyLandingController(void)
     // FIXME: Use altitude controller if available (similar to MC code)
     rcCommand[ROLL] = pidAngleToRcCommand(failsafeConfig()->failsafe_fw_roll_angle, pidProfile()->max_angle_inclination[FD_ROLL]);
     rcCommand[PITCH] = pidAngleToRcCommand(failsafeConfig()->failsafe_fw_pitch_angle, pidProfile()->max_angle_inclination[FD_PITCH]);
-    rcCommand[YAW] = pidRateToRcCommand(failsafeConfig()->failsafe_fw_yaw_rate, currentControlRateProfile->rates[FD_YAW]);
+    rcCommand[YAW] = -pidRateToRcCommand(failsafeConfig()->failsafe_fw_yaw_rate, currentControlRateProfile->rates[FD_YAW]);
     rcCommand[THROTTLE] = failsafeConfig()->failsafe_throttle;
 }