Smart actuation for helicopter rotorblades

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Abstract

Successful rotorcrafts were only achieved when the differences between hovering flight conditions and a stable forward flight were understood. During hovering, the air speed on all helicopter blades is linearly distributed along each blade and is the same for each. However, during forward flight, the forward motion of the helicopter in the air creates an unbalance. The airspeed is increased for the blade passing in the advancing side of the helicopter, while it is reduced in the retreating side. Moreover, when each blade enters the retreating side of the helicopter, a reverse flow occurs around the profile where the blade speed is lower than the forward speed of the helicopter. The balance of a rotorcraft is solved by a cyclic pitch control, but trade-offs are made on the blade design to cope with the great variety of aerodynamic conditions. A smart blade that would adapt its characteristics to this large set of conditions would improve rotorcrafts energy efficiency while providing vibration and noise control. Smart rotor blades systems are studied to adapt the aerodynamic characteristics of the blade during its revolution and to improve the overall performances. An increase in the lift over drag ratio on the retreating side has been studied to design a blade with better aerodynamic efficiency and better stall performances in the low-speed region. The maximum speed of a rotorcraft is limited by the angle of attack that the profile can sustain on the retreating side before stall. Therefore, increasing the maximum angle of attack that a profile geometry can sustain increases the rotorcraft flight envelope. Flow asymmetry and aerodynamic interaction between successive blades are also investigated to actively reduce vibrations and limit noise. These improvements can be achieved by deploying flaps, by using flow control devices or by morphing the full shape of the profile at a specific places during the blade revolution. Each of the listed methods has advantages and disadvantages as well as various degrees of feasibility and integrability inside helicopter blades. They all modify the aerodynamic characteristics of the profile. Their leverage on the various aerodynamic effects depends on the control strategy chosen for actuation. Harmonic actuation is therefore studied for active noise and vibration control whereas stepped deployment is foreseen to modify the stall behaviour of the retreating side of the helicopter. Helicopter blades are subjected to various force constraints such as the loads from the complex airflow and the centrifugal forces. Furthermore, any active system embedded inside a rotor blade needs to comply with the environmental constraints to which a helicopter will be subjected during its life-span. Other concerns, like the power consumption and the data transfer for blade control, play an important role as well. Finally, such a system must have a life-time exceeding the life-time of a rotor blade and meet the same criteria in toughness, reliability and ease of maintenance. Smart system is an interplay of aerodynamics, rotor-mechanics, material science and control, thus a multidisciplinary approach is essential. A large part of the work consists in building processes to integrate these domains for investigating, designing and testing smart components. Piezoelectric actuators are a promising technology to bring adaptability to rotor blades. They can be used directly on the structure to actively modify its geometry, stiffness and aerodynamic behaviour or be integrated to mechanisms for the deployment of flaps. Their large specific work, toughness, reliability and small form factor make them suitable components for integration within a rotor blade. The main disadvantage of piezoelectric actuators is the small displacement and strain available. Amplification mechanisms must be optimised to produce sufficient displacement in morphing applications. Smart actuation systems placed inside rotor blades have the potential to improve the efficiency and the performances of tomorrow's helicopters. Piezoelectric materials can address many of the challenges of integrating smart components inside helicopter blades. The key aspect remains the collaboration between various domains, skills and expertise to successfully implement these new technologies.
Original languageEnglish
Title of host publicationSmart actuation and sensing systems - Recent advances and future challenges
EditorsG. Berselli, R. Vertechy, G. Vassura
PublisherIntechOpen
Pages657-678
Number of pages22
ISBN (Print)978-953-51-0798-9
DOIs
Publication statusPublished - 2012

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Helicopters
Aerodynamics
Turbomachine blades
Rotors
Flaps
Piezoelectric actuators
Vibration control
Angle of attack
Toughness
Flight envelopes
Active noise control
Acoustic variables control
Geometry
Piezoelectric materials
Materials science
Data transfer
Air
Flow control
Embedded systems
Amplification

Keywords

  • IR-81963
  • METIS-288309
  • Onderzoek van algemene industriele aardMechanical engineering and technology

Cite this

Paternoster, A., Loendersloot, R., de Boer, A., & Akkerman, R. (2012). Smart actuation for helicopter rotorblades. In G. Berselli, R. Vertechy, & G. Vassura (Eds.), Smart actuation and sensing systems - Recent advances and future challenges (pp. 657-678). IntechOpen. https://doi.org/10.5772/51438
Paternoster, Alexandre ; Loendersloot, Richard ; de Boer, Andries ; Akkerman, Remko. / Smart actuation for helicopter rotorblades. Smart actuation and sensing systems - Recent advances and future challenges. editor / G. Berselli ; R. Vertechy ; G. Vassura. IntechOpen, 2012. pp. 657-678
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abstract = "Successful rotorcrafts were only achieved when the differences between hovering flight conditions and a stable forward flight were understood. During hovering, the air speed on all helicopter blades is linearly distributed along each blade and is the same for each. However, during forward flight, the forward motion of the helicopter in the air creates an unbalance. The airspeed is increased for the blade passing in the advancing side of the helicopter, while it is reduced in the retreating side. Moreover, when each blade enters the retreating side of the helicopter, a reverse flow occurs around the profile where the blade speed is lower than the forward speed of the helicopter. The balance of a rotorcraft is solved by a cyclic pitch control, but trade-offs are made on the blade design to cope with the great variety of aerodynamic conditions. A smart blade that would adapt its characteristics to this large set of conditions would improve rotorcrafts energy efficiency while providing vibration and noise control. Smart rotor blades systems are studied to adapt the aerodynamic characteristics of the blade during its revolution and to improve the overall performances. An increase in the lift over drag ratio on the retreating side has been studied to design a blade with better aerodynamic efficiency and better stall performances in the low-speed region. The maximum speed of a rotorcraft is limited by the angle of attack that the profile can sustain on the retreating side before stall. Therefore, increasing the maximum angle of attack that a profile geometry can sustain increases the rotorcraft flight envelope. Flow asymmetry and aerodynamic interaction between successive blades are also investigated to actively reduce vibrations and limit noise. These improvements can be achieved by deploying flaps, by using flow control devices or by morphing the full shape of the profile at a specific places during the blade revolution. Each of the listed methods has advantages and disadvantages as well as various degrees of feasibility and integrability inside helicopter blades. They all modify the aerodynamic characteristics of the profile. Their leverage on the various aerodynamic effects depends on the control strategy chosen for actuation. Harmonic actuation is therefore studied for active noise and vibration control whereas stepped deployment is foreseen to modify the stall behaviour of the retreating side of the helicopter. Helicopter blades are subjected to various force constraints such as the loads from the complex airflow and the centrifugal forces. Furthermore, any active system embedded inside a rotor blade needs to comply with the environmental constraints to which a helicopter will be subjected during its life-span. Other concerns, like the power consumption and the data transfer for blade control, play an important role as well. Finally, such a system must have a life-time exceeding the life-time of a rotor blade and meet the same criteria in toughness, reliability and ease of maintenance. Smart system is an interplay of aerodynamics, rotor-mechanics, material science and control, thus a multidisciplinary approach is essential. A large part of the work consists in building processes to integrate these domains for investigating, designing and testing smart components. Piezoelectric actuators are a promising technology to bring adaptability to rotor blades. They can be used directly on the structure to actively modify its geometry, stiffness and aerodynamic behaviour or be integrated to mechanisms for the deployment of flaps. Their large specific work, toughness, reliability and small form factor make them suitable components for integration within a rotor blade. The main disadvantage of piezoelectric actuators is the small displacement and strain available. Amplification mechanisms must be optimised to produce sufficient displacement in morphing applications. Smart actuation systems placed inside rotor blades have the potential to improve the efficiency and the performances of tomorrow's helicopters. Piezoelectric materials can address many of the challenges of integrating smart components inside helicopter blades. The key aspect remains the collaboration between various domains, skills and expertise to successfully implement these new technologies.",
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Paternoster, A, Loendersloot, R, de Boer, A & Akkerman, R 2012, Smart actuation for helicopter rotorblades. in G Berselli, R Vertechy & G Vassura (eds), Smart actuation and sensing systems - Recent advances and future challenges. IntechOpen, pp. 657-678. https://doi.org/10.5772/51438

Smart actuation for helicopter rotorblades. / Paternoster, Alexandre; Loendersloot, Richard; de Boer, Andries; Akkerman, Remko.

Smart actuation and sensing systems - Recent advances and future challenges. ed. / G. Berselli; R. Vertechy; G. Vassura. IntechOpen, 2012. p. 657-678.

Research output: Chapter in Book/Report/Conference proceedingChapterAcademicpeer-review

TY - CHAP

T1 - Smart actuation for helicopter rotorblades

AU - Paternoster, Alexandre

AU - Loendersloot, Richard

AU - de Boer, Andries

AU - Akkerman, Remko

N1 - Open access

PY - 2012

Y1 - 2012

N2 - Successful rotorcrafts were only achieved when the differences between hovering flight conditions and a stable forward flight were understood. During hovering, the air speed on all helicopter blades is linearly distributed along each blade and is the same for each. However, during forward flight, the forward motion of the helicopter in the air creates an unbalance. The airspeed is increased for the blade passing in the advancing side of the helicopter, while it is reduced in the retreating side. Moreover, when each blade enters the retreating side of the helicopter, a reverse flow occurs around the profile where the blade speed is lower than the forward speed of the helicopter. The balance of a rotorcraft is solved by a cyclic pitch control, but trade-offs are made on the blade design to cope with the great variety of aerodynamic conditions. A smart blade that would adapt its characteristics to this large set of conditions would improve rotorcrafts energy efficiency while providing vibration and noise control. Smart rotor blades systems are studied to adapt the aerodynamic characteristics of the blade during its revolution and to improve the overall performances. An increase in the lift over drag ratio on the retreating side has been studied to design a blade with better aerodynamic efficiency and better stall performances in the low-speed region. The maximum speed of a rotorcraft is limited by the angle of attack that the profile can sustain on the retreating side before stall. Therefore, increasing the maximum angle of attack that a profile geometry can sustain increases the rotorcraft flight envelope. Flow asymmetry and aerodynamic interaction between successive blades are also investigated to actively reduce vibrations and limit noise. These improvements can be achieved by deploying flaps, by using flow control devices or by morphing the full shape of the profile at a specific places during the blade revolution. Each of the listed methods has advantages and disadvantages as well as various degrees of feasibility and integrability inside helicopter blades. They all modify the aerodynamic characteristics of the profile. Their leverage on the various aerodynamic effects depends on the control strategy chosen for actuation. Harmonic actuation is therefore studied for active noise and vibration control whereas stepped deployment is foreseen to modify the stall behaviour of the retreating side of the helicopter. Helicopter blades are subjected to various force constraints such as the loads from the complex airflow and the centrifugal forces. Furthermore, any active system embedded inside a rotor blade needs to comply with the environmental constraints to which a helicopter will be subjected during its life-span. Other concerns, like the power consumption and the data transfer for blade control, play an important role as well. Finally, such a system must have a life-time exceeding the life-time of a rotor blade and meet the same criteria in toughness, reliability and ease of maintenance. Smart system is an interplay of aerodynamics, rotor-mechanics, material science and control, thus a multidisciplinary approach is essential. A large part of the work consists in building processes to integrate these domains for investigating, designing and testing smart components. Piezoelectric actuators are a promising technology to bring adaptability to rotor blades. They can be used directly on the structure to actively modify its geometry, stiffness and aerodynamic behaviour or be integrated to mechanisms for the deployment of flaps. Their large specific work, toughness, reliability and small form factor make them suitable components for integration within a rotor blade. The main disadvantage of piezoelectric actuators is the small displacement and strain available. Amplification mechanisms must be optimised to produce sufficient displacement in morphing applications. Smart actuation systems placed inside rotor blades have the potential to improve the efficiency and the performances of tomorrow's helicopters. Piezoelectric materials can address many of the challenges of integrating smart components inside helicopter blades. The key aspect remains the collaboration between various domains, skills and expertise to successfully implement these new technologies.

AB - Successful rotorcrafts were only achieved when the differences between hovering flight conditions and a stable forward flight were understood. During hovering, the air speed on all helicopter blades is linearly distributed along each blade and is the same for each. However, during forward flight, the forward motion of the helicopter in the air creates an unbalance. The airspeed is increased for the blade passing in the advancing side of the helicopter, while it is reduced in the retreating side. Moreover, when each blade enters the retreating side of the helicopter, a reverse flow occurs around the profile where the blade speed is lower than the forward speed of the helicopter. The balance of a rotorcraft is solved by a cyclic pitch control, but trade-offs are made on the blade design to cope with the great variety of aerodynamic conditions. A smart blade that would adapt its characteristics to this large set of conditions would improve rotorcrafts energy efficiency while providing vibration and noise control. Smart rotor blades systems are studied to adapt the aerodynamic characteristics of the blade during its revolution and to improve the overall performances. An increase in the lift over drag ratio on the retreating side has been studied to design a blade with better aerodynamic efficiency and better stall performances in the low-speed region. The maximum speed of a rotorcraft is limited by the angle of attack that the profile can sustain on the retreating side before stall. Therefore, increasing the maximum angle of attack that a profile geometry can sustain increases the rotorcraft flight envelope. Flow asymmetry and aerodynamic interaction between successive blades are also investigated to actively reduce vibrations and limit noise. These improvements can be achieved by deploying flaps, by using flow control devices or by morphing the full shape of the profile at a specific places during the blade revolution. Each of the listed methods has advantages and disadvantages as well as various degrees of feasibility and integrability inside helicopter blades. They all modify the aerodynamic characteristics of the profile. Their leverage on the various aerodynamic effects depends on the control strategy chosen for actuation. Harmonic actuation is therefore studied for active noise and vibration control whereas stepped deployment is foreseen to modify the stall behaviour of the retreating side of the helicopter. Helicopter blades are subjected to various force constraints such as the loads from the complex airflow and the centrifugal forces. Furthermore, any active system embedded inside a rotor blade needs to comply with the environmental constraints to which a helicopter will be subjected during its life-span. Other concerns, like the power consumption and the data transfer for blade control, play an important role as well. Finally, such a system must have a life-time exceeding the life-time of a rotor blade and meet the same criteria in toughness, reliability and ease of maintenance. Smart system is an interplay of aerodynamics, rotor-mechanics, material science and control, thus a multidisciplinary approach is essential. A large part of the work consists in building processes to integrate these domains for investigating, designing and testing smart components. Piezoelectric actuators are a promising technology to bring adaptability to rotor blades. They can be used directly on the structure to actively modify its geometry, stiffness and aerodynamic behaviour or be integrated to mechanisms for the deployment of flaps. Their large specific work, toughness, reliability and small form factor make them suitable components for integration within a rotor blade. The main disadvantage of piezoelectric actuators is the small displacement and strain available. Amplification mechanisms must be optimised to produce sufficient displacement in morphing applications. Smart actuation systems placed inside rotor blades have the potential to improve the efficiency and the performances of tomorrow's helicopters. Piezoelectric materials can address many of the challenges of integrating smart components inside helicopter blades. The key aspect remains the collaboration between various domains, skills and expertise to successfully implement these new technologies.

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KW - METIS-288309

KW - Onderzoek van algemene industriele aardMechanical engineering and technology

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Paternoster A, Loendersloot R, de Boer A, Akkerman R. Smart actuation for helicopter rotorblades. In Berselli G, Vertechy R, Vassura G, editors, Smart actuation and sensing systems - Recent advances and future challenges. IntechOpen. 2012. p. 657-678 https://doi.org/10.5772/51438