VTOL Rotor Restart Sequencing for Smoother Landing Transition
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Solution Overview
Problem
VTOL aircraft experience deteriorated ride comfort due to large thrust changes when VTOL rotors are restarted after being stopped during cruise, as the rotation is resumed for vertical landing.
Innovation Solution
The VTOL rotors are divided into groups and the stop control is sequentially canceled on a group-by-group basis, using a controller to manage the rotation of each rotor, ensuring gradual thrust increase during the transition from cruise to landing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rotation of VTOL rotors is stopped during cruise to reduce drag, then drag is reduced, but ride comfort deteriorates when rotors are restarted for landing
Solution Approach 1:
The VTOL rotors are divided into multiple groups (first group and second group) and restarted sequentially rather than simultaneously. The controller cancels stop control for the first group, waits for rotational speed to reach a target value, then cancels stop control for the second group. This segmentation of the restart operation reduces the sudden thrust change that would otherwise deteriorate ride comfort.
Solution Approach 2:
The controller performs preliminary action by first canceling stop control for the first group of rotors and waiting for them to reach a predetermined rotational speed before canceling stop control for the second group. This preliminary sequencing ensures that thrust is added gradually, preventing sudden vertical acceleration that would compromise ride comfort during the transition from cruise to landing.
2Speed
If all VTOL rotors are restarted simultaneously for landing, then vertical thrust is generated quickly, but thrust change is large and ride comfort deteriorates
Solution Approach 1:
The VTOL rotors are segmented into multiple groups that are restarted sequentially. The controller manages the restart process by first activating the first group of rotors, allowing them to reach a target rotational speed, then activating the second group. This segmentation prevents the simultaneous restart of all rotors, thereby reducing the total thrust change magnitude while still achieving quick vertical thrust generation for landing.
Solution Approach 2:
The controller implements periodic action by introducing time delays between the restart of different rotor groups. After canceling stop control for the first group, the controller waits for the rotational speed to reach a predetermined value before proceeding to cancel stop control for the second group. This periodic sequencing ensures smooth thrust buildup, preventing sudden vertical acceleration and maintaining ride comfort during the transition to landing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes the change in vertical thrust, thereby improving ride comfort by maintaining a more stable transition from cruise to landing.
Implementation Method 1
a plurality of vertical take-off and landing rotors configured to generate thrust in a vertical direction
Implementation Method 2
at least one cruise rotor configured to generate thrust in a horizontal direction
Implementation Method 3
at least one wing configured to generate lift as the vertical take-off and landing aircraft moves in the horizontal direction
Implementation Method 4
the controller is configured to: perform stop control for stopping a rotation operation of each of the plurality of vertical take-off and landing rotors during flight of the vertical take-off and landing aircraft; and in a case of canceling the stop control of the plurality of vertical take-off and landing rotors, perform cancellation of the stop control sequentially on a group-by-group basis
Data Source
AI summary
A plurality of VTOL rotors are divided into a plurality of groups, and each VTOL rotor is included in any one of the groups. A controller can perform stop control for stopping the rotation operation of each VTOL rotor during flight, and in a case of canceling the stop control of the plurality of VTOL rotors, the controller performs cancellation of the stop control sequentially on a group-by-group basis.