Optimal placement of trailing-edge flaps for helicopter vibration reduction using response surface methods

Abstract

This study aims to determine optimal locations of dual trailing-edge flaps to achieve minimum hub vibration levels in a helicopter, while incurring low penalty in terms of required trailing-edge flap control power. An aeroelastic analysis based on finite elements in space and time is used in conjunction with an optimal control algorithm to determine the flap time history for vibration minimization. The reduced hub vibration levels and required flap control power (due to flap motion) are the two objectives considered in this study and the flap locations along the blade are the design variables. It is found that second order polynomial response surfaces based on the central composite design of the theory of design of experiments describe both objectives adequately. Numerical studies for a four-bladed hingeless rotor show that both objectives are more sensitive to outboard flap location compared to the inboard flap location by an order of magnitude. Optimization results show a disjoint Pareto surface between the two objectives. Two interesting design points are obtained. The first design gives 77 percent vibration reduction from baseline conditions (no flap motion) with a 7 percent increase in flap power compared to the initial design. The second design yields 70 percent reduction in hub vibration with a 27 percent reduction in flap power from the initial design.

Configuration optimization of dampers for adjacent buildings under seismic excitations

“…Viswamurthy andGanguli 2007, Mezyk 2002 andreferences therein). However, very little has been done with regard to optimizing the use of dampers to decrease seismic damage.…”

Optimal Placement of Piezoelectric Actuated Trailing-Edge Flaps for Helicopter Vibration Control

“…Few studies have used a rigorous approach for the optimal placement of flaps to maximize the benefits of the active flap system. In one such study, Viswamurthy and Ganguli adopted an optimization approach for the spanwise placement of flaps in a dual-flap configuration to maximize the benefit of vibration reduction while minimizing flap power [27]. They used a polynomial response surface to approximate the vibration and flap-power objectives in terms of the location of the inboard and outboard flaps.…”

“…This approach decoupled the aeroelastic control problem from the optimal flap placement problem while also drastically reducing the computational time of the optimization process. However, it must be mentioned that several other studies ignored the presence of hysteresis in the trailing-edge flap actuators [24][25][26][27].…”

Optimal Piezoelectric Actuators and Sensors Configuration for Vibration Suppression of Aircraft Framework Using Particle Swarm Algorithm

“…Rao et al [6] proposed particle swarm based evolutionary optimization technique for optimal placement of piezoelectric patch actuators and accelerometer sensors to suppress vibration. Viswamurthy and Ganguli [7,8] proposed a response surface based optimization method for actuator and sensor placement. Manning [9] proposed a two-stage 2 Mathematical Problems in Engineering optimization strategy for active member placement and strut cross section and compensator parameter optimization for intelligent trusses.…”