AP_Scripting: script to disable subset of motors in fwd flight

this script allows quadplanes to disable a subset of tilt motors in
forward flight

libraries/AP_Scripting/examples/q_fwd_mask.lua

@@ -0,0 +1,120 @@
+--[[
+   a script to disable a subset of tilting motors in forward flight
+--]]
+
+local PARAM_TABLE_KEY = 87
+local PARAM_TABLE_PREFIX = "QFWD_"
+
+local MAV_SEVERITY = {
+    EMERGENCY = 0,
+    ALERT = 1,
+    CRITICAL = 2,
+    ERROR = 3,
+    WARNING = 4,
+    NOTICE = 5,
+    INFO = 6,
+    DEBUG = 7
+}
+
+local k_thrust_out = 126
+local k_motor1 = 33
+
+local PERIOD_MS = 25
+
+-- bind a parameter to a variable
+function bind_param(name)
+   return Parameter(name)
+end
+
+-- add a parameter and bind it to a variable
+function bind_add_param(name, idx, default_value)
+   assert(param:add_param(PARAM_TABLE_KEY, idx, name, default_value), string.format('could not add param %s', name))
+   return bind_param(PARAM_TABLE_PREFIX .. name)
+end
+
+-- setup quicktune specific parameters
+assert(param:add_table(PARAM_TABLE_KEY, PARAM_TABLE_PREFIX, 8), 'could not add param table')
+
+--[[
+  // @Param: QFWD_MASK
+  // @DisplayName: VTOL Tilt forward mask
+  // @Description: Mask of VTOL motors to disable in forward flight
+  // @Bitmask: 0:Motor 1, 1:Motor 2, 2:Motor 3, 3:Motor 4, 4:Motor 5, 5:Motor 6, 6:Motor 7, 7:Motor 8, 8:Motor 9, 9:Motor 10, 10:Motor 11, 11:Motor 12
+  // @User: Standard
+--]]
+local QFWD_MASK = bind_add_param('MASK', 1, 0)
+
+--[[
+  // @Param: QUIK_RC_FUNC
+  // @DisplayName: VTOL tilt forward mask enable function
+  // @Description: RCn_OPTION number to use to enable motor masking
+  // @User: Standard
+--]]
+local QFWD_AUX_FUNC = bind_add_param('AUX_FUNC', 2, 300)
+
+-- the PWM to set the VTOL motors to when disabled
+local Q_M_PWM_MIN = Parameter('Q_M_PWM_MIN')
+
+local is_masked = false
+
+--[[
+   return true if we should mask the motors
+--]]
+local function should_mask_motors()
+   local sw_current = rc:get_aux_cached(QFWD_AUX_FUNC:get())
+   if sw_current ~= 2 then
+      -- function not active
+      return false
+   end
+   if QFWD_MASK:get() == 0 then
+      -- nothing to mask
+      return false
+   end
+
+   -- see if VTOL motors running, don't mask if running
+   local thrust = SRV_Channels:get_output_scaled(k_thrust_out)
+   if thrust > 0 then
+      return false
+   end
+
+   if quadplane:in_vtol_mode() or quadplane:in_assisted_flight() then
+      return false
+   end
+
+   return true
+end
+
+local function update_motors()
+   local should_mask = should_mask_motors()
+   if should_mask ~= is_masked then
+      if should_mask then
+         gcs:send_text(MAV_SEVERITY.INFO, "QFWD mask enabled")
+      else
+         gcs:send_text(MAV_SEVERITY.INFO, "QFWD mask disabled")
+      end
+      is_masked = should_mask
+   end
+   if not should_mask then
+      -- rely on timeout
+      return
+   end
+   local mask = QFWD_MASK:get()
+   for i = 0,7 do
+      if ((1<<i) & mask) ~= 0 then
+         local id = k_motor1 + i
+         local chan = SRV_Channels:find_channel(id)
+         if chan then
+            SRV_Channels:set_output_pwm_chan_timeout(chan, Q_M_PWM_MIN:get(), PERIOD_MS*4)
+         end
+      end
+   end
+end
+
+function update()
+   update_motors()
+   return update, PERIOD_MS
+end
+
+gcs:send_text(MAV_SEVERITY.INFO, "Loaded QFWD masking")
+
+return update, PERIOD_MS