The New Type Piezoelectric Actuator And Application In The Morphing Wing

Morphing wing can realize the optimal objective through changing its aerodynamic layout according to the outside flight environment.Morphing wing technology is a transformational technology of improving the integration performance of aircraft,which is of great significance to the development of aircraft.One of the key techniques to realize morphing aircraft is the actuator,which should provide enough driving force if significant changes of span,sweep angle and wing area are accomplished by the aircraft wing.The piezoelectric actuator is not affected by electromagnetic radiation in space.It can work in vacuum,high and low temperature environments.It is very suitable for using in the aerospace field.In this paper,a new piezoelectric rotation actuator is proposed and applications in wing structure of morphing aircraft to drive the wing to change span and sweep angle.First of all,in consideration of the requirement of piezoelectric rotation actuator,piezoelectric constitutive equation of piezoelectric materials is introduced.Mechanical properties,electrical properties and hysteresis characteristics of piezoelectric stack are investigated.Output displacements of PSt1000/16/60VS25 piezoelectric stack is tested.The research results could provide useful theoretical basis and data reference to design piezoelectric rotation actuator.According to the deficiencies of high cost for traditional piezoelectric rotation actuators requires a plurality of clamping piezoelectric stack to realize stepping rotation,a new type piezoelectric rotation actuator with two displacement amplification mechanisms to transform linear elongation movement of piezoelectric stack into ratchet rotor rotation.The piezoelectric rotation actuator with one drive piezoelectric stack achieves the clamping function by using the ratchet mechanism,reduces the cost of the actuator.According to the deficiencies of rotation resolution not adjustable for traditional piezoelectric rotation actuators,a intermittent rotating mechanism is proposed to be as the actuator rotor.The rotation resolution can be adjusted by changing pawl interval angle and the pawl number of pawl group.Flexure hinge mechanisms as the key components of piezoelectric rotation actuator are studied.The mechanical characteristics of straight circular flexure hinge are studied.The effect of design parameters on rotational stiffness of straight circular flexure hinge is analyzed.Flexible displacement amplification mechanism is proposed to be as the first stage displacement amplification mechanism of piezoelectric rotation actuator.Dynamic model based on pseudo-rigid-body model is established.Natural frequency model based on energy method is established which is verified by finite element software ANSYS and the test.Dynamics model of flexible piezoelectric driven displacement amplification mechanism based onanalytical mechanics method is established.The response is calculated by transfer function.The effect of design parameters on amplification multiple of the triangle displacement amplification mechanism is analyzed.Parallelogram displacement amplification mechanism is proposed to be as the second stage displacement amplification mechanism of piezoelectric rotation actuator.Experimental test system of piezoelectric rotary actuator is built.The performance testing of the prototype piezoelectric rotary actuator are carried out in order to test and analysis the performance parameters of the actuator.Finally,the structures of span morphing wing and sweep morphing wing are design with NACA 4412 rib sections.The FLUENT is used for aerodynamic simulation analysis.The effect of flight parameters,span and sweep angle on lift-drag ratio is analyzed.Driven mechanism based on the piezoelectric rotary actuator is proposed to drive wings deformation.The deformation results are verified by the ADAMS and the test.The results show that the proposed driven mechanism with piezoelectric rotary actuator actuator is feasible and has good performance.The new type piezoelectric rotation actuator offer a number of advantages,including low cost,easy to install adjustable and controllable good.These advantages enable it to have a high innovation potential in application.The span morphing wing and sweep morphing wing can improve aerodynamic performance by deformation to reduction in fuel consumption when the aircraft subsonic flight.The preliminary study on piezoelectric rotary actuator drives wings change span and sweep provides a technical basis for applying piezoelectric actuator in morphing aircraft in aerospace and military fields,has a certain value of engineering applications and theoretical significance.