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DESIGN: AeroVantage ~ Control (Flight & Power) - Logic - 1x2 - Overview

Flight and Power ~ since both are to be electric.

General information; much of which to be moved to lower detail pages as this section grows.

Electronic Mixer Box:

Note that the following axes are based on the PropRotors not the fuselage. They are only the same when the PropRotor is in the cruise mode. The X-axis is the rotor's axis of rotation. The Z-axis is the rotor/motor's tilt axis (lateral axis). The X-axis normal to the X-Y plane.

Pitch Input: Forward and aft motions on the cyclic 'stick' produce;-

Basic:

Hover: - identical longitudinal thrust vector changes about the Y-axis of both rotors. A thrust differential would have produced a yaw cross-coupling.

Transition: - identical thrust vector changes about the Y-axis of both rotors. The reading from the tilt sensors at the two rotors will input the ratio of this mix.

Cruise: - differential thrust of the rotors. A thrust differential would have produced a roll cross-coupling.

Airplane Control Surfaces:

Elevator ~ mechanical connection.

Computerized Smoothing:

Roll Input: Left and right motions on the 'stick' produce;-

Basic:

Hover: - Concern: See; AeroVantage ~ Trim, Stability & Control - Stability

Transition: - an action of the two rotors that is a mix of those for hover and cruise. The reading from the tilt sensors at the two rotors will input the ratio of this mix.

Cruise: - differential thrust between the two rotors. The roll is produced by the difference in the induced drag between the two rotors. This could be produced by collective differential OR if there is a desire to have the collective only linked to the tilt use differential rpm. I THINK THAT COLLECTIVE MUST BE USED BY THE FLIGHT-CONTROLS.

Airplane Control Surfaces:

Aileron ~ mechanical connection.

Computerized Smoothing:

Yaw Input: Rotational motions on the foot pedals;-

Basic:

Hover: - opposing lateral thrust vectors about the Z-axis of both rotors. Due to the 3º to 4º precone angle the forgoing MAY be true ~ if not then ....

Transition: an action of the two rotors will be a mix of those for hover and cruise. The reading from the tilt sensors at the two rotors will input the ratio of this mix.

Cruise: opposed lateral blade pitch change on both rotors or identical thrust vector changes about the Z-axis of both rotors.

Airplane Control Surface:

Rudder ~ mechanical connection.

Computerized Smoothing:

Climb: Collective lever or ..... on Joy stick. It is achieved by increasing the pitch of both PropRotors.

Basic:

Hover:

Transition:

Cruise:

Airplane Control Surface:

Computerized Smoothing:

The encoders maintain the speed of the (constant speed) motors by pulse width modulation. The exception being the pilot's overriding On/Off switch.

Throttle Input: Grip on collective lever or thumb switch on Joy stick

Increases the rpm of both motors in unision.

Transition:

'Beep' momentary contact toggle switch on the cyclic stick (or joy-stick). This causes the transition actuators to rotate all PropRotors while at the same time changing the pitch of the PropRotors. Increasing the pitch as rotating toward cruise.

Airplane Control Surface:

Elevators may have to be adjusted.

Computerized Smoothing:

Collective and Power, due to motor governor, on both PropRotors and motors varies with the till angle.

Thoughts re Airplane Flight Controls:

During forward flight the use of conventional fixed-wing flight controls, as compared to changes to the proprotors thrust and tilt, will probably result in the fore and aft streamtube maintaining a better alignment???

These controls should probably be mechanical for simplicity.

If these controls were in conjunction with the PropRotor flight controls, they would;

Act as a safety backup (redundancy).
They would reduce the workload on the PropRotors' actuators.

Notes:

The cyclic control will be needed for the 1x2 PropRotor, whereas it may not be needed for the 2x4.

In hover the control will be somewhat similar to that of a tandem helicopter, OTHER: Flight Dynamics - Control (Response). One difference is that the PropRotors will be extremely rigid for fast response.

Airplane control surfaces will compliment the PropRotor control and will serve as duplicity for safety. Look into further

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Individual Blade Control:

Perhaps a swashplate is not required.

The PropRotors will be experiencing a remote airflow that will be very close to being normal to the rotor disks; during hover, transition and cruise. In other words, the rotors will not be experiencing the remote airflow vector that a regular helicopter experiences during cruise. For example, forward flight may be instigated by activating the transition mechanism and not by pushing the cyclic stick forward.
Assuming that the collective is changed relatively infrequently and that 1P cyclic change is of small angles then the blade pitch actuators might connected directly to the blade instead of being used to change the plane of the swashplate.
For forward flight; ailerons, elevator and rudder might be incorporated, They could compliment the blade pitch actuators or totally replace the use of the blade pitch actuators. This 'duplication' could be a safety feature, at least during forward flight.

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Spider: This may not be the way to go.

Consider shaping the props cone so that it aerodynamically screws the free airflow into cooling the motor.

Outside Information:

See DESIGN: AeroVantage ~ PropRotor - Outside Information - BA609, V-22 and V-44 (quad), Eagle Eye TiltRotors ~or~ Flight Controls ~ V-22 Osprey

Hover:

Design and Control of an Indoor Micro Quadrotor Algorithims etc. - Have hard copy.

"Control of the V-22 in the hover/low-speed regime is achieved through cyclic and collective inputs to the swashplate...."

Cruise:

Gyros, accelerometers?, Velocity sensors?

Transition:

From Curtiss-Wright X-19 " Initially, the nacelle tilt rate was mechanized at 5 degrees per second. It was soon realized that this would have required a deceleration from 90km/h to hover in less than 5 seconds, resulting in 0.5g of longitudinal acceleration. This was too much, so the rate was reduced to 1 degree per second, resulting in a more reasonable 0.2g."

There is also is some information, on the site, on the time required for transition. It was copied from a students paper.

Autopilot:

Autopilot: Do it yourself UAV ~~ PCBFlyer?

And More:

Procerus Technologies Review the whole site. Kestrel™ Autopilot - heavy duty, feather-light. 16.7 grams. Introducing the world's smallest, lightest full-featured mini autopilot for small and micro UAVs.

"Design and control of quadrotors with application to autonomous flying". Saved on E-drive (stikk) as Quad-Rotor_ EPFL_TH3727.pdf

Handling Qualities Degradation in Tilt-Rotor Aircraft Following Flight Control System Failures, Saved in Removable Stick as ERF-2004-paper.pdf

Onboard Inputs:

Gyros (3) ~ Pitch, Roll and yaw

Potentiometer ~ Tilt

Potentiometer (4) ~ Collective ?

Thoughts on Operation:

Consider making the collective automatic (mechanical) with the change of the tilt. This will result in two only cyclic rods. Note that on the XV-15 Differential collective pitch produces aircraft roll and differential cyclic pitch results in yaw motions.

Safety:

See AeroVantage ~ Control (Flight & Power) - Failure

Both configurations can accommodate safety parachutes.

Last Revised: September 6, 2009