The two factors which influence the low temperature performance of deformable mirrors（DMs） are the piezoelectric stroke of the actuators and the thermally induced surface deformation of the DM. A new theory was prop...The two factors which influence the low temperature performance of deformable mirrors（DMs） are the piezoelectric stroke of the actuators and the thermally induced surface deformation of the DM. A new theory was proposed to explain the thermally induced surface deformation of the DM： because the thermal strain between the actuators and the base leads to an additional moment according to the theory of plates, the base will be bent and the bowing base will result in an obvious surface deformation of the facesheet. The finite element method（FEM） was used to prove the theory. The results showed that the thermally induced surface deformation is mainly caused by the base deformation which is induced by the coefficient of thermal expansion（CTE） mismatching; when the facesheet has similar CTE with the actuators, the surface deformation of the DM would be smoother. Then an optimized DM design was adopted to reduce the surface deformation of the DMs at low temperature. The low temperature tests of two 61-element discrete PZT actuator sample deformable mirrors and the corresponding optimized DMs were conducted to verify the simulated results. The results showed that the optimized DMs perform well.展开更多
When a fast-steering mirror(FSM)system is designed,satisfying the performance requirements before fabrication and assembly is vital.This study proposes a structural parameter design approach for an FSM system based on...When a fast-steering mirror(FSM)system is designed,satisfying the performance requirements before fabrication and assembly is vital.This study proposes a structural parameter design approach for an FSM system based on the quantitative analysis of the required closed-loop bandwidth.First,the open-loop transfer function of the FSM system is derived.In accordance with the transfer function,the notch filter and proportional-integral(PI)feedback controller are designed as a closed-loop controller.The gains of the PI controller are determined by maximizing the closed-loop bandwidth while ensuring the robustness of the system.Then,the two unknown variables of rotational radius and stiffness in the open-loop transfer function are optimized,considering the bandwidth as a constraint condition.Finally,the structural parameters of the stage are determined on the basis of the optimized results of rotational radius and stiffness.Simulations are conducted to verify the theoretical analysis.A prototype of the FSM system is fabricated,and corresponding experimental tests are conducted.Experimental results indicate that the bandwidth of the proposed FSM system is 117.6 Hz,which satisfies the minimum bandwidth requirement of 100 Hz.展开更多
A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting...A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11178004)
文摘The two factors which influence the low temperature performance of deformable mirrors（DMs） are the piezoelectric stroke of the actuators and the thermally induced surface deformation of the DM. A new theory was proposed to explain the thermally induced surface deformation of the DM： because the thermal strain between the actuators and the base leads to an additional moment according to the theory of plates, the base will be bent and the bowing base will result in an obvious surface deformation of the facesheet. The finite element method（FEM） was used to prove the theory. The results showed that the thermally induced surface deformation is mainly caused by the base deformation which is induced by the coefficient of thermal expansion（CTE） mismatching; when the facesheet has similar CTE with the actuators, the surface deformation of the DM would be smoother. Then an optimized DM design was adopted to reduce the surface deformation of the DMs at low temperature. The low temperature tests of two 61-element discrete PZT actuator sample deformable mirrors and the corresponding optimized DMs were conducted to verify the simulated results. The results showed that the optimized DMs perform well.
基金This work was supported by the Science Challenge Project(Grant No.JCKY2016212A5060105).
文摘When a fast-steering mirror(FSM)system is designed,satisfying the performance requirements before fabrication and assembly is vital.This study proposes a structural parameter design approach for an FSM system based on the quantitative analysis of the required closed-loop bandwidth.First,the open-loop transfer function of the FSM system is derived.In accordance with the transfer function,the notch filter and proportional-integral(PI)feedback controller are designed as a closed-loop controller.The gains of the PI controller are determined by maximizing the closed-loop bandwidth while ensuring the robustness of the system.Then,the two unknown variables of rotational radius and stiffness in the open-loop transfer function are optimized,considering the bandwidth as a constraint condition.Finally,the structural parameters of the stage are determined on the basis of the optimized results of rotational radius and stiffness.Simulations are conducted to verify the theoretical analysis.A prototype of the FSM system is fabricated,and corresponding experimental tests are conducted.Experimental results indicate that the bandwidth of the proposed FSM system is 117.6 Hz,which satisfies the minimum bandwidth requirement of 100 Hz.
基金supported by the Technology Project of Changchun City(No.2013270)
文摘A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.
