Numerical simulation of pararotor dynamics: Effect of mass displacement from blade plane

Piechocki, Joaquín; Mora, Vicente Nadal; Sanz-Andrés, Ángel

doi:10.1016/j.ast.2016.04.004

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…In the present study, the flight and rotation speed of SIV are chosen to be approximately 20-80 m s −1 , 20-40 r/s, respectively, which are higher than those for decelerators with parachutes (≈10 m s −1 , 4 r/s [1,38]) or wings (≈20 m s −1 and 12 r/s [2,13,14,[39][40][41][42][43]). However, compared with aviation vehicles, (e.g., rockets, missiles, airplanes, etc) that rely on rotation and fins to achieve a stable flight [44], the flight speed and rotation speed of SIV are much lower.…”

Section: The Force Acting On Sivmentioning

confidence: 99%

Dynamic analysis of a skeet-inspired vehicle to achieve a spiral scanning detection motion

Yang,

Ding,

Sun

2024

Phys. Scr.

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A short cylindrical vehicle (the ratio of length to diameter is less than 2) equipped with an outer/inner detector is developed, which is inspired by the Tennis racket theorem and Olympic skeet shooting sports to achieve a regular scanning spiral on the ground. The sensitivity of the asymmetric mass distribution of the skeet-inspired vehicle (SIV) to the spatial position of the inertial principal axis is evaluated. Subsequently, a dynamics model with six degrees of freedom for the SIV at a large initial angle of attack (≈60–90°) is established. The numerical results of solving the dynamic differential equations indicate that the special initial conditions—namely, high initial flying velocity and rotational speed—are prerequisites for achieving the regular scanning spiral. Additionally, the analysis demonstrates that asymmetric mass distribution, rather than asymmetric aerodynamics, serves as the key factor in achieving the regular scanning spiral in the present skeet-inspired vehicle. Our new strategy, using the principal axes as the initial rotation axis, offers better scanning performance (such as a larger detection area, faster scan frequency, and more stable scanning motion) compared to the other platforms (e.g., rotating decelerators with wings or parachutes) that rely on asymmetrical aerodynamics. The analyses can provide guidance for the structural design of various types of spiral scanning vehicles.

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Section: The Force Acting On Sivmentioning

confidence: 99%

Dynamic analysis of a skeet-inspired vehicle to achieve a spiral scanning detection motion

Yang,

Ding,

Sun

2024

Phys. Scr.

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“…Nadal-Mora and Sanz-Andr es (2006) obtained the stability range of pararotors via equations of motion, and Piechocki et al (2008) developed an analytical model and analyzed the stability of a type of pararotor whose blade is aligned with the mass center of the whole system. Additionally, in Piechocki et al (2014Piechocki et al ( , 2016, parameters such as displacement of mass center affecting their dynamic behavior were examined, and in Francisco-Martiarena et al (2015), the influence of aspect ratio on their performance was shown experimentally. Kellas (2007) designed, constructed and controlled a singlebladed vehicle deploying no motors in the auto-rotating phase.…”

Section: Introductionmentioning

confidence: 99%

An analytical solution and stability analysis of asymmetric non-actuator guided projectiles

Taban,

Novinzadeh

2024

AEAT

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Purpose One of the challenges encountered in the design of guided projectiles is their prohibitive cost. To diminish it, an appropriate avenue many researchers have explored is the use of the non-actuator method for guiding the projectile to the target. In this method, biologically inspired by the flying concept of the single-winged seed, for instance, that of maple and ash trees, the projectile undergoes a helical motion to scan the region and meet the target in the descent phase. Indeed, the projectile is a decelerator device based on the autorotation flight while it attempts to resemble the seed’s motion using two wings of different spans. There exists a wealth of studies on the stability of the decelerators (e.g. the mono-wing, samara and pararotor), but all of them have assumed the body (exclusive of the wing) to be symmetric and paid no particular attention to the scanning quality of the region. In practice, however, the non-actuator-guided projectiles are asymmetric owing to the presence of detection sensors. This paper aims to present an analytical solution for stability analysis of asymmetric decelerators and apprise the effects of design parameters to improve the scanning quality. Design/methodology/approach The approach of this study is to develop a theoretical model consisting of Euler equations and apply a set of non-dimensionalized equations to reduce the number of involved parameters. The obtained governing equations are readily applicable to other decelerator devices, such as the mono-wing, samara and pararotor. Findings The results show that the stability of the body can be preserved under certain conditions. Moreover, pertinent conclusions are outlined on the sensitivity of flight behavior to the variation of design parameters. Originality/value The analytical solution and sensitivity analysis presented here can efficiently reduce the design cost of the asymmetric decelerator.

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“…La componente en la dirección j W b se considera nula, asumiendo la hipótesis de que el flujo a través de la pala es bidimensional. Esto se debe a que, a lo largo del eje j W b , la componente aerodinámica es de menor orden que en las otras direcciones, y tiene un comportamiento cíclico alrededor de un valor promedio nulo [29].…”

Section: Matriz De Transformación Del Sistema Wb Al W1bunclassified

“…Existen distintos estados aerodinámicos en los que puede hallarse sumergido un rotor, que se encuentran desarrollados en la bibliografía de referencia [27], [30], [29]. Para el caso en estudio, puede suponerse que la relación entre la velocidad de descenso, U W , y la velocidad inducida, v i , es mayor, en valor absoluto, a 2.…”

Section: Velocidad Inducidaunclassified

Estudio del desplazamiento lateral de un decelerador de alas rotatorias de pequeño alargamiento a través de las variaciones cíclicas del paso de las palas

Martiarena¹

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El objetivo de la presente tesis es el estudio del comportamiento de un decelerador de alas rotatorias, denominado pararrotor, ante las variaciones cíclicas del ángulo de paso de las palas. En particular, se investiga la posibilidad de controlar el desplazamiento lateral de un pararrotor mediante las variaciones cíclicas del ángulo de paso de las palas, y, extendiendo el análisis, controlar la trayectoria del dispositivo en régimen de descenso, de modo de satisfacer los requerimientos operacionales. El pararrotor es un decelerador aerodinámico que vuela en régimen de autorrotación, es decir, que no extrae ni comunica energía del medio. La descripción aerodinámica formal de su comportamiento se basa en una adaptación de la teoría de elemento de pala, ya que no se realiza la integral a lo largo de la envergadura si no que se supone la fuerza aerodinámica resultante concentrada en un punto de la pala, en virtud del pequeño alargamiento de las mismas. El modelo teórico desarrollado comienza con la formulación de las ecuaciones que describen los efectos dinámicos de las variaciones cíclicas del ángulo de paso. Las fuerzas y torques aerodinámicos son estimados mediante un modelo completo de la pala, obteniéndose una expresión matemética que permite conocer la fuerza y el momento a lo largo de una vuelta. Del análisis de las magnitudes modeladas se observa que los efectos dinámicos son sensiblemente menores que los aerodinámicos, por lo que se puede suponer que los últimos son los dominantes en el cálculo de las acciones dinámicas que alteran el comportamiento del pararrotor. En cuanto al desarrollo experimental, se construyó un modelo a escala con control del ángulo de paso de las palas para ser montado en el túnel de viento, junto a un arreglo adecuado de elementos de medición y adquisición de datos. Con estos ensayos se buscó calcular experimentalmente parámetros característicos que permitieron validar el modelo teórico. Se demostrará que las variaciones cíclicas del ángulo de paso de las palas permiten modificar el torque que se genera sobre el pararrotor y, por lo tanto, es factible utilizar este efecto como elemento de control sobre el dispositivo. También se realizaron una serie de simulaciones numéricas, a partir de un modelo promediado de las fuerzas y los momentos sobre el pararrotor a lo largo de una revolución que fue utilizado en el modelo completo. Estas simulaciones permitieron establecer estados de operacién cercanos al equilibrio a partir de soluciones obtenidas para un modelo simplificado de la dinámica del pararrotor.

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Numerical simulation of pararotor dynamics: Effect of mass displacement from blade plane

Cited by 5 publications

References 19 publications

Dynamic analysis of a skeet-inspired vehicle to achieve a spiral scanning detection motion

Dynamic analysis of a skeet-inspired vehicle to achieve a spiral scanning detection motion

An analytical solution and stability analysis of asymmetric non-actuator guided projectiles

Estudio del desplazamiento lateral de un decelerador de alas rotatorias de pequeño alargamiento a través de las variaciones cíclicas del paso de las palas

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