Mixers: add geoms quad_vtail (tilted props) and quad_y (rear coax props)

quad_vtail: reverse prop direction (same quad_h) to combine yaw torque induced by propellers and yaw torque induced by tilted rotors.

src/modules/systemlib/mixer/CMakeLists.txt

@@ -39,6 +39,8 @@ set(geom_files
 	quad_plus.toml
 	quad_wide.toml
 	quad_deadcat.toml
+	quad_vtail.toml
+	quad_y.toml
 	quad_x_pusher.toml
 	hex_x.toml
 	hex_plus.toml

src/modules/systemlib/mixer/geoms/quad_vtail.toml

@@ -0,0 +1,34 @@
+# Quadcopter in Y configuration with rear props tilted at 45 degrees
+
+[info]
+name = "quad_vtail"
+key = "4vt"
+description = "Quadcopter in Y configuration with rear props tilted at 45 degrees"
+
+[rotor_default]
+direction = "CW"
+axis      = [0.0, 0.0, -1.0]
+Ct        = 1.0
+Cm        = 0.05
+
+[[rotors]]
+name      = "front_right"
+position  = [0.2, 0.2, 0.0]
+direction = "CW"
+
+[[rotors]]
+name      = "rear_left"
+position  = [-0.3, -0.1, -0.1]
+axis      = [0.0, 0.707106, -0.707106]
+direction = "CW"
+
+[[rotors]]
+name     = "front_left"
+position = [0.2, -0.2, 0.0]
+direction = "CCW"
+
+[[rotors]]
+name     = "rear_right"
+position = [-0.3, 0.1, -0.1]
+axis      = [0.0, -0.707106, -0.707106]
+direction = "CCW"

src/modules/systemlib/mixer/geoms/quad_y.toml

@@ -0,0 +1,32 @@
+# Quadcopter in Y configuration with coax rear props
+
+[info]
+name = "quad_y"
+key = "4y"
+description = "Quadcopter in Y configuration with coax rear props"
+
+[rotor_default]
+direction = "CW"
+axis      = [0.0, 0.0, -1.0]
+Ct        = 1.0
+Cm        = 0.05
+
+[[rotors]]
+name      = "front_right"
+position  = [0.2, 0.2, 0.0]
+direction = "CCW"
+
+[[rotors]]
+name      = "rear_top"
+position  = [-0.2, 0.0, -0.1]
+direction = "CCW"
+
+[[rotors]]
+name     = "front_left"
+position = [0.2, -0.2, 0.0]
+direction = "CW"
+
+[[rotors]]
+name     = "rear_bottom"
+position = [-0.2, 0.0, 0.1]
+direction = "CW"