An irradiation experiment for an image-intensified sensor (Intensified Complemetary Metal-oxide Semiconductor,ICMOS ) was performed with a 60Co-γ ray source to evaluate its weak-light-detecting ability under the total dose irradiation. When the total dose of irradiation reached the predetermined point, the change of photoelectric response capability of the sensor was measured quantitatively by an off line method. The experiment results show that as the total dose of irradiation increases, the photoelectric response capability decreases rapidly. When the total dose of irradiation reaches 60 krad(Si), the photoelectric response capability is reduced to 6%. The causes of decline of the photoelectric response capability were analyzed according to the components of the image-intensified sensor and empirical equations of the decline of the photoelectric response capability were also derived. The experiments demonstrate that the decline of the photoelectric response capability is compensated by improving the voltage gain of the image-intensified sensor. When the total dose of irradiation reaches 25 krad(Si), the photoelectric response capability still maintains 100% by improving the voltage gain of the image-intensified sensor of 0.23 V meanwhile maintaining a good weak-light-detecting ability. These findings show that the image-intensified sensor is able to withstand 25 krad(Si) of the total dose irradiation.

The Liquid Crystal Display(LCD) module in a high power TEA CO2 laser is easy to couple with electromagnetic interference, so as to affect the normal work of the laser. Therefore, this paper explores the prediction method of Electromagnetic Compatibility (EMC)for the LCD module under transient irradiation in an electromagnetic field. The coupling mechanism of electromagnetic interference received by the LCD module integrated in the laser system was analyzed. On the basis of the coupling of field and line , the field line electromagnetic interference of the LCD module was analyzed and calculated by using the BLT equation in the Taylor form, then, the prediction results were verified by several experimentally. The experimental results show that the interference voltage produced by connect cables coupled with electromagnetic fields on the data lines of LCD display module is 1 V, and exceeds the noise margin of the circuit. So the EMC control measures must be taken to ensure the performance of the LCD module. Moreover, the verification experiments indicate that prediction results for the EMC has correctly reflected the actual EMC performance of LCD module. The method has a guiding significance for prediction and design of EMC of electrical equipment in high-power TEA CO2 lasers.

In order to precisely measure the surface topography of a diamond grinding wheel in a non-contact way, an interferometry based special topographic measurement system was established and the principle and key techniques of the system were investigated. On the basis of the principle of vertical scanning white light interferometry and the characteristics of measured objects, an approach suitable for grinding wheel measurement was presented. Then, the key techniques such as automatic scanning range determination, larger vertical scanning, three dimensional surface reconstruction and abrasive grain recognition, were analyzed. With a specific setup for wheel fixing, a wheel measurement system was given based on the proposed method and its stitching method for a larger area evaluation was analyzed experimentally. Experimental results indicate that the correlation coefficient of the regions before and after stitchings is more than 0.8 by using area-based method with an overlapping area of 30%-50%. The height error of the stitched area is less than 0.4 μm. The system recovers the three dimensional surface of the grinding wheel and obtained measuring ranges and accuracy meet the requirements for analysis and evaluation of grinding wheels.

A no-common path calibration system was desighned for the Adaptive Optical (AO) system in a 1.23 m ground telescope. To solve some practical problems of no-common path static aberration calibration, the evaluation function for the multi-channel Phase Diversity (PD) processing method was presented for a condition of the defocusinng amount difficult to be measured. Then, a method to use the detected aberration and the modulated deformable mirror to iterate each other for convergence was proposed to make up the effect of nonideal measurement conditions on aberration detection. As compared with two-channel PD processing, the multi-channel PD processing method has stronger tolerance to the forms of target sources and higher accuracy of wavefront solution in theory . The processing method was used to measure the no-common path aberration of the AO system in the 1.23 m telescope. Experimental results demonstrate that the proposed method achieves the higher accuracy of wavefront solution and the aberration has been compensated by using the initial bias of a deformable mirror.Moreover, the whole imaging quality of the optical system is improved effectively.

When a surface-bonded Fiber Bragg Grating (FBG) sensor is used to measure the strain of a host material, it will effect the strain distribution of the host material. Therefore, this paper explores the relationship between optical fiber strain and host material strain. A theoretical model of strain transfer of the host material to the optical fiber was presented to modify the measured strain, and the interaction between FBG sensor and host material was considered. Finally, the theoretical predictions proposed in this paper were verified by Finite Element Analysis(FEA) and practical experiments. The results show that the error between FEA and theoretical solution is controlled within 5%, and that between theoretical solution and experimental data is controlled within 8%. These mean that the strain transfer mode satisfies the accuracy requirement of surface-bonded FBG sensors. Moreover, the effects of geometrical and material parameters on the average strain transfer rate and the strain transfer rate were analyzed. The obtained results indicate that the average strain transfer rate and the strain transfer rate increase with the Young's modulus of the host material. However, they decrease with increasing the top thickness and bottom thickness of an adhesive layer.

An optical system for full aperture backscatter diagnose was designed for a novel inertial confinement fusion facility. Several key technologies about optical design were discussed. A wedge mirror with low reflectance was used to attenuate the backscatter lights before diagnosis, so the films of optical elements in the diagnostic system were survived after many shots. A telescope optical system was used to reduce the sizes of the beam as well as the sizes of the optical elements, meanwhile the optical path was folded several times by mirrors to shrink the volume of the whole system. The space filter, dichroic filter, optical filters and colored glasses were combined to simultaneously eliminate the stray light. Moreover, a scatter plate was taken to average the signals to ensure the fiber coupler to obtain needed signals including all wavelengths studied. Based on the analysis of imaging beam structures, a lens was designed for the imaging of parabolic mirror, and a camera was used to record the space distribution of scattered lights on the surface of parabolic mirror. The diagnosis system was designed to provide measurements for scattering time, scattering spectrum, near-field imaging, and scattered energy and its whole sizes are 1.9 m×0.9 m×1.5 m. The full aperture backscatter system designed in this paper has potential applications to the new inertial confinement fusion facility.

A LD side-pumped 589 nm small-scale all-solid-state laser with an intra-cavity sum-frequency structure was developed and the experiments for exciting the brightness of a sodium guide star by the laser were described. The numerical simulation method was employed to analyze and design the cavity length and the position of a sum-frequency crystal, and it shows a smaller size and higher conversion efficiency. A synchronous power system in time domain was developed to compensate the delay between pulses of the two fundamental lasers. Special films were coated on the sides of the splitter mirror to obtain linear polarized laser as well as to increase the conversion efficiency and the thermal stability. Moreover, etalons and special coating methods were employed to suppress the oscillation of 1 338 nm spectral line. Finally, a dedicated launch telescope and a receive system were used for the generation and observation of sodium guide star. Test results show that the laser offers an output power more than 8 W, a repetition frequency of 5 kHz and the linewidth less than 3.5 GHz, meanwhile, its conversion efficiency is up to 2% corresponding to the 808 nm pump power. Under the sky background light of Changchun, the brightness of the guide star excited by the laser in winter experiments is about 10 Mv.

In high speed free space optical communication systems, the efficiency that a laser beam is coupled into a single-mode fiber is an important factor. However, the laser propagation through atmospheric turbulence degrades the fiber coupling efficiency. According to the relation between turbulence intensity and optical system resolution, this paper explores the effect of atmospheric turbulence on fiber coupling efficiency, and derives the relationship of the receiving aperture, focal length, the wavelength of incident light, fiber radius and atmospheric coherence length with the single mode fiber coupling efficiency. Two methods were proposed to improve the fiber coupling efficiency in a turbulence environment. The first method is to maintain the coupling efficiency to be the maximum by adjusting the focal length of the coupling system when turbulence environment is deteriorated. The second one is to use a taper fiber in receiving end of the focal plane to improve the coupling efficiency. Finally, corresponding analysis, simulation and a coupling efficiency experiment at outdoor were performed, and it verifies the effectiveness of the improved method for fiber coupling efficiency.

For the special use demands of ultraviolet warning cameras, the structures, distortion balances and the consistency of image plane illumination of ultra wide-angle optical systems were analyzed. An ultraviolet optical system with a large field of view of 120° and a large relative aperture of 1/2 was designed. The system is a double imaging configuration with the spectral range from 0.254 m to 0.272 m. By using inverse telephoto structure, its back working length is 7.48 mm. A quasi-telecentric optical system was selected to improve the illumination uniformity for off-axis and on-axis view fields. Then, by choosing optical materials and distributing the focal powers reasonably, the optical system was optimized. The experiments demonstrate that the system is characterized by smaller imaging distortion and uniform image plane illumination, the dispersion spot diameter is smaller than 63.5 m, and the relative distortion at 0.71 field of view, the relative illumination uniformity for off-axis and on-axis view fields are less than 20% and 10%,respectively. The structure of the whole system is compact and feasible, and is suitable for ultraviolet warning cameras.

To measure the stress and deformation inside resin composites rapidly and dynamically, a B-scan method based on phase contrast spectral optical coherence tomography was employed to measure the out-of-plane displacement field and strain field of the resin composites with voiding defect. A bending experiment and a thermal deformation experiment were conducted for composite samples through mechanical charging and thermal loading. Then the phase difference data from experiments were unwrapped and the out-of-plane displacement field distribution and strain field distribution were obtained. The results show that the experiments descript clearly of the dynamical deformation course around the voiding defect inside composites, from which bigger displacement and strain have been observed in the stress concentration region rather than the undamaged part, and an area with the depth 1 mm below the sample surface is measured. Moreover, this method is able to measure the displacement field in a sub-micro meter level and the deformation courses of composites in dynamics, and is an effective analysis method for mechanical properties of composites.

As pin holes of sintered silicon carbide formed in manufacturing process cause serious surface scattering of mirrors, this paper proposes a surface modification technique to decrease the surface scattering of sintered silicon carbide mirror. A silicon layer was deposited by plasma ion assisted deposition technique on the mirror as a surface modification coating to eliminate the defects on the mirror surface and to decrease the surface scattering effectively. A scanning electron microscope was applied to characterize of the morphology of the sintered silicon carbide sample, and the surface scattering origin was systematically analyzed. A total integrated scattering instrument was established. Then the total integrated scatterings of the sintered silicon carbide samples before and after surface modifications and a fine polished K9 glass sample were measured. The results indicate that the total integrated scatterings of the sintered silicon carbide sample before and after surface modifications are 3.92% and 1.42%, respectively, and that of the K9 glass sample is 1.36%. The surface root mean square roughnesses of the sintered silicon carbide sample after surface modification polishing and the fine polished K9 glass sample are 1.63 nm and 1.04 nm respectively. These results demonstrate that the defect of the sintered silicon carbide is successfully eliminated after surface modification, the surface scattering is greatly decreased, furthermore the surface optical performance is quite close to that of the K9 glass.

To reduce the speckle phenomenon caused by atmospheric boundary layer on an optical window in airborne laser communication, the aero-optics effect and corresponding suppression method for the atmospheric boundary layer were discussed. Based on the type of experimental airplane and the position of equipment installation, the parameters of shape, thickness of the optical window were designed optimally, and the deformation of optical window and air flow field distribution were analyzed in the simulation and the optical window was improved. Finally, a series of compensating glasses were developed to solve defocusing of the receiving spot caused by the atmospheric boundary layer. A flight experiment was performed at the flight distance of 10-140 km and the flight altitude of 1 500-4 500 m and the compensation results were analyzed. The results show when the compensating glass with final focal length of 5.5×105 m is added into the receiving optical path, the atmospheric boundary layer is actively restrained by compensated optical window, the shape of receiving spot is improved and the receiving power distribution variance is reduced by 1/3. These results mean that the window after compensation reduces the effect of atmospheric boundary layer on laser communication effectively.

An improved calibration method for robotic visual flexible measurement systems was proposed and a mathematical model for hand-eye errors and kinematic parameter errors of a robot was established. The robotic flexible visual measurement system was set up with a line-structured laser sensor mounted on the robot end and a standard sphere was fixed in the robot workspace as the calibration target.In the calibration, the robot was controlled to measure the coordinates of the standard sphere center at different poses. The initial hand-eye transformation was firstly identified by theoretical kinematic parameters of the robot, then, based on constraint of sphere center,the exact hand-eye transformation and real kinematic parameters were identified with an iterative algorithm at the same time. A calibration experiment for the robotic flexible visual measurement system was performed based on an ABB IRB2400 robot and the accuracy verification experiment was conducted by a laser tracker. The results show that the distance standard deviations of the robotic visual flexible measurement system before and after calibrations have been reduced from 0.566 mm to 0.173 mm, which verifies the validity and practicability of the method proposed. The method improves the accuracy of the hand-eye relationship and does not need external measuring devices, so is suitable for industrial applications.

According to the characteristics of datum axis measurement by using a Coordinate Measuring Machine (CMM), a method based on 3D convex hulls was proposed to realize the datum plane fitting. Firstly, the 3D convex hulls of discrete sampling points were rapidly constructed by using "gift encapsulated algorithm" based on the computational geometric theory. According to the definition of datum axis in Datum Reference Frames (DRF), the constrained degrees of freedom as well as the method to establish the datum axis were determine by the priority of datum axis and the features of other datum. Then, the mathematical equation of datum axis was used to resolve the constrained axis into a rotational vector and a translational vector and then to establish mathematical models with constrained datum axis rotation and constrained datum axis translation. Finally, the variable domain of datum axis was obtained by using 3D convex hulls based on material requirements. The experiment demonstrate that the results of datum axis determined by proposed method is the same as that of the CMM least square method in an unconstrained axis processing, however, it has more different as copared with that in a constrained axis processing. Fortunately, the method ensures the relative position relationship between the constrained axes, and it accords with the principle of establishing datum axes and meets the requirements of engineering applications.

A twice stepped limiting program by presetting on north was designed to improve the efficiency of limiting process of a gyrotheodolite. The principle of traditional stepped limiting was introduced, and the relationship of the swing balance and the zero position of gyrotheodolite was analyzed. Then ,the traditional program of zero position following was redesigned to a balance position following now,so that the gyro could quickly limit the swing of the gyro and allow it to campaign with a small swing near north through stepping twice. The mathematical formulas for two stepping angles and time were derived, the error factors on the limiting effect were analyzed and the different swing ranges and the coefficient ratios of suspensory torsions to gyro torques were simulated. Finally, the program was applied to a pendulous gyroscope. The theory and experiment results show that the limiting is implemented in an un-following gyro precession circle with a limiting precision of 1′. The program proposed reaches the precision index and time demand of north-finding without adding any software, and improves the efficiency of limiting.

To explore the effect of space environment on the working life of solid-lubricated rotating parts and forecast their working life in orbit, the influence of space environment on solid-lubricated films was analyzed. The analysis points out that three main factors are relative to the working life of the space rotating parts, which are space launch environment, vacuum degree and alternating temperature. A life test was designed to simulate the three factors, in which the mechanical test was used to simulate space launch environment, and the thermal vacuum test was taken to simulate the vacuum and alternating temperature. The X-ray Energy Dispersive Spectrometer (EDS)was used to analyze the film composition of the unworn race and the worn race for a bearing in the solid-lubricated rotating part as well as ball surface materials.The analysis results show that the transfer film has not formed. On the result, it forecasts that the working life of the solid-lubricated rotating part in the test would be up to 107 times. Finally, it gives some necessary suggests that should been taken to increase the reliability and improve the work life of space rotating parts.

To improve the strength of composite wing skin of a Unmanned Aerial Vehicle(UAV), the stacking sequence of honeycomb sandwich structure wing skin was designed optimally by a genetic algorithm. According to the design variables' discrete characteristics of the composite, the genetic algorithm based on an integral code strategy was presented. In consideration of the Tsai-Wu criterion, the fitness function was proposed and the constrain conditions were given by the stacking sequence principle of composite laminate layout. Then, the optimized stacking sequence scheme for skin composite structure was obtained by optimization design. Finally, the rationality of the composite laminate layout was verified by finite element analysis and static experiments. The experimental results show that the maximum deformations of the left and right wing tips are 116.02 mm and 105.36 mm,respectively, which meet the requirements that the best deformation is less than 180 mm. Ultrasonic inspection was performed and no damage is detected, which means that the wing structure meets the demands of engineering applications. An UAV with the composite wing skin was flown out successfully, and it verifies the feasibility of proposed design.

To overcome the linearizated errors from the attitude estimation algorithm based on Extended Kalman Filter ( EKF), a new attitude estimation algorithm based on gravity/magnetic assisted Euler angle Unscented Kalman Filter ( UKF)algorithm was proposed to improve the attitude measuring accuracy of a low cost Micro-electro-mechanic System(MEMS). The gravity and magnetic data were used to inhibit the rapid divergence of attitude error for the MEMS. The Euler angles were taken as UKF states and the quaternion was used to calculate the attitude in time update, so that the algorithm avoids the quaternion standardized problem and solves the low attitude accuracy of Euler angles. Without linearization errors of the UKF, it has better stability and attitude estimation accuracy. By taking measured MEMS Inertial Measurement Unit (IMU )data for experiments, the results show that the measuring accuracy of pitch and roll angles by proposed algorithm has improved nearly 20 percent respectively and the heading accuracy improved by 12.1 percent as compared with that of the attitude estimation algorithm based on the EKF. It concludes that the proposed method has better precision. However, the convergence time of UKF has increased due to the insufficient estimation for state variances.

The triethanolamine (TEA) with different concentrations was added to the slurry to lap of quartz crystal. By defining the ratio of Material Removal Rate(MRR) and Pad Wear Rate (PWR) as the wear ratio, the effects of TEA concentrations on the magnitude and stability of quartz crystal, MRR, PWR, wear ratio, Friction Coefficient (COF), Acoustic Emission (AE) and the surface quality of quartz crystal after lapping were investigated in fixed abrasive lapping process. The results show that with increasing additive amount of TEA in the slurry, the wear ratio increases first and then decreases, and the magnitude and stability of MRR for the quartz crystal have the same variation trend, too. Moreover, the COF decreases first and then increases and AE increases first and then decreases. The surface quality of quartz crystal after lapping gets first better then goes bad. When TEA concentration is 5%, the MRR of quartz crystal is the maximum and most stable, and the service life of FAP is the longest and surface quality is the best. Obtained results indicate that to add appropriate amount of TEA in the slurry will stabilize the lapping process of quartz crystal, prolong the service life of pad, enhance the surface quality of work pieces and reduce production costs in lapping process.

A novel compact vibration isolator was designed and constructed to attenuate the vibration of space optical payload for a optical remote sensor with a larger aperture and high resolution. The main structural parameters and arrangement forms of the isolator were researched. Firstly, the finite element method was used to analyze the relationship between main structural parameters and three-dimensional stiffness properties of the isolator. Then, the BP network was taken to predict the three-dimensional stiffness of the isolator and to search the structural parameters that accords with conditions of the isolator. A symmetric radial arrangement form of isolator was presented, along with the theoretical model and FEA simulation by combining the general structure of optical payload. Finally, a prototype of the vibration isolator was fabricated and experimental studies were carried out. Experimental results indicate that the natural frequency of the isolator system is approximately 5.31 Hz and the vibration attenuation effect is more than 20 dB when the vibration frequency is higher than 25 Hz. The maximum error of FEA simulation is less than 8% compared with the real test. It is shown that this vibration isolator can attenuate the jitter induced by spacecrafts effectively.

A key dwell time algorithm in bonnet polishing was investigated to get the high-precision optical surface. Firstly, the removal function of bonnet polishing was acquired from the process experiments. Based on the matrix iteration, an appropriate initial dwell time function was given to calculate the dwell time with the liminal removal method . Then, the variance of the residual error was considered to optimize the result of dwell time function and to acquire the dwell time function quickly.The method is suitable for polishing the optical elements such as aspheric surface, and free-form surface. A simulation experiment was performed on a residual surface error through MATLAB, and the results show that the residual error PV value has reached up to 0.1 μm. Finally, an optical glass surface was processed on the bonnet polishing machine developed by ourselves, and results show that its surface roughness Ra is reduced from 0.159 μm to 0.024 μm and the PV value from 0.756 μm to 0.158 μm. Moreover, the rationality of the dwell time algorithm was verified. It demonstrates that the matrix-based algorithm satisfies the requirement of optical precision machining very well and provides theoretical basis for bonnet polishing of complex optical elements.

To design a force/tactile feedback device with compact construct and a larger workspace, the kinematics analysis and working space algorithm were researched based on the Delta mechanism. Based on the improved Delta mechanism, a chain offset angle alpha was introduced. Positive and inverse kinematics were established by the vector method and their correctness were verified by taking a deduced equation as an example. According to the inverse kinematics formula, the envelope body equation of single-open-chain subspace was deduced and the geometric shape of the subspace was drawn under three situations while the length of drive rod is more than or equals to or less than that of oscillating rod. Then the influence of alpha on the whole workspace and mechanism size was deeply discussed. The relations between the offset angle and the volume of the maximum inscribed sphere, the offset angle and the whole mechanism size were derived using the numerical method. Moreover, the cross section view of the space was plotted by MATLAB. Finally, the maximum inscribed sphere was taken as the design space,and a design example was given by using the Jacobin matrix condition number. The results after verifying show that the designed mechanism meets requirements of optimized design Delta mechanisms.

According to the demand of a protecting device of an explosive bolt for structure sizes, a shunt-would protecting device was designed to unlock the redundant connection between a space camera and a satellite. On the basis of the ladder-like profile of the explosive bolt, the protection of explosive bolt on the space camera was implemented by introducing the flexure plate absorb the kinetic energy of bolts to deform. According to the feature of true σ-ε curve in the yield stage, the strength limit was used as a threshold to determine the structures to be fail or not, and the ratio of plastic strain to fail strain was adopted to estimate the safety performance of the device. Then, Abaqus/Explicit was used to analyze the protecting effect of device suffering from the collision. Finally, a physical experiment was carried out to validate further the design. The simulation results show that protecting bolts made of TC4 suffer the maximum stress about 897 MPa, less than strength limit; and the maximum strain is about 2.2%, less than allowable plastic strain (about 2.6%). These results indicate that the device endures the impact from explosive bolts with sufficient safety. The experiment shows that protecting plate presents light plastic deformation, and each part of the device has complete structure without a fracture or splinter. The proposed design is characterized by a compact size and effective protecting performance.

On the basis of rheological behaviors of abrasive flow, the stress tensor was analyzed to explore the micro-cutting force of the Abrasive Flow Machining (AFW) process. It points out that the abrasive flow precision machining is a combined machining method made by extrusion and micro removal, and the micro-cutting force of the AFW is come from a combination of medium share force, squeezing force and plowing force. The dynamics model was established and general change law of the micro-cutting force in AFW processing were revealed quantitatively by changing processing conditions and processing parameters, such as the pressure of contact region, removal amounts and surface roughness. Finally, the shear force was simulated numerically by using the CFD module of COMSOL multiphysics software. The experiment results show that the mold core is conductive to increasing the micro-cutting force, the surface roughness Ra of the solider (number four) has decreased from 2.918 μm to 1.027 μm and the removal is 0.09 g after 15 processing cycles. The results demonstrate that the removal is changed in the abrasive flow machining process, however, the removal action is quick weakened with the increase of the times of extrusion and the surface roughness is still improved.

To automatically detect the tool wear state in metal cutting process, an automatic detection method based on image processing was proposed by analysis of the gray levels of a tool wear image in the background area, wear area and the unworn area. Firstly, the automatic determination algorithms of the upper-and lower-thresholds were respectively presented according to the Otsu method and B-spline curve fitting method. Based on the algorithms, the gray-contrasts between wear area and background area as well as wear area and unworn areas were enhanced. By analysis of the stable region within three areas and the non-stable region at two edges in the tool wear image, the local gray-level variance threshold algorithm was presented for the boundary extraction. An adaptive threshold of the local variance was defined, by which the tool wear region was segregated from the tool wear image clearly. On this basis, the morphological method was used to fill out the holes of the segregated part, so that the corresponding geometric parameters of the wear areas were precisely achieved. Experimental results show that the detection errors of the wear width and the wear length are respectively 1.024% and 1.325% when the magnification of 3D microscope is 50, whereas they are 0.661% and 0.995% when the magnification is 100. The proposed method is characterized by strong anti-interference, and higher detection accuracy. It can supply the technology support for improving the tool utilization, guaranteeing the machining quality, and saving the manufacturing cost.

The extraction method of kinematic formula for a drift adjusting mechanism in space cameras was researched to accurately control the drift adjusting mechanism and to improve the imaging quality. The distribution law of test data for the drift adjusting mechanism was analyzed, and the model of distribution law was built. Based on three-parameter trigonometric function fitting method by use of angular frequency ω one-dimensional search, the test data were handled by the least square fitting. The distribution law of fitting residual was studied, and the inherent error components were extracted and modified, so that the fitting accuracy was further improved. The test results show that on basis of the kinematic formula of drift adjusting mechanism extracted by the proposed method, the control precision of drift adjusting system is less than 30″, equal to that of least square fitting (maximum fitting deviation 20.5107″). The kinematic formula also satisfies the requirements of control system, realizes high precision control of the drift angle and reduces the demand for part processing, assembling, and production costs.

A spot tracking closed-loop system for the control of a one-to-many laser communication net was introduced. On the basis of the closed-loop position of the servo rotary table, the closed-loop beam tracking system which takes a CCD camera as the sensor and a two-dimensional servo rotary table as the actuator was discussed particularly. The mathematical principle of the tracking system was introduced and static and dynamic errors of every link in the closed-loop beam system and the responses of open-loop and close-loop were researched also. After theoretical calculation and mathematical simulation , a closed-loop tracking programming was written. Then, a control algorithm combined the classical PID control and feedforward control was used to further improve the servo bandwidth and to guarantee the stability of the system. The tracking experiment on spot positions in laser communication was performed and the result shows that tracking error is 3σ≈136 μrad, which meets the demands of laser pointing in laser communication nets. The obtained results verify the feasibility of control strategy, and lay the foundation for the multiple beam servo.

As the very small vibration of an aerostatic bearing limits its applications in ultra-precision machining, this paper analyzes experimentally the dynamical characteristics of the aerostatic bearing and proposes a structure design with an equalizing groove to solve the problem mentioned above. To realize the mechanical characteristics of aerostatic bearings, the analytical model was set up by using the finite element analysis software FLUENT and the performance parameters of the aerostatic bearing were obtained. The mechanism for the occurrence of small vibration was analyzed and the methods to add an equalizing groove on the surface of the aerostatic bearing to reduce the small vibration were proposed. The experiments were performed to verify the proposed method and the results show that the experiment results are good consistent with the analysis results. It indicates that the small vibration can be successfully suppressed by 80% with the proposed equalizing groove, which improves the stability and operation accuracy of the aerostatic bearing and is a useful exploring for suppressing the small vibration of aerostatic bearings and improving the accuracy of whole machine tool.

How to improve the measuring accuracy of a roundness measuring instrument was researched in consideration of the cylindricity error requirement and cylindricity error assessment searching algorithm. To reduce inclination error of a workpiece in measuring cylindricity error, a leveling method using a dual-point vertical layout was proposed and analyzed. According to the direction cosine of the axis of workpiece, the amount of leveling was defined and calculated to overcome the problem brought by manual adjustment technology and the accurate leveling and high precise measurement were completed. As the assessment of cylindricity error is to search for a cylinder axis that statisfies the minimum condition and the Nelder-Mead simplex method has lower convergence precision and convergence rate because it depends on initial solution,so that a combined algorithm with quasi-Newton method and simplex algorithm was proposed to achieve the fast and accurate search for global optimums.The Matlab simulation and experimental testing on classical functions indicate that the combined algorithm improves the convergence rate and convergence precision effectively and the convergence rate has been increased over 50% and convergence precision increases over once as compared with that of Nelder-Mead simplex method, which ensures and improves the measuring precision of workpieces.

Three dimensional(3D) object recognition was researched under multi-view points. For the shortages of traditional signal feature description for 3D object recognition under multi-view points, a new recognition algorithm fusing multiple features was proposed. Firstly, the object corners were extracted by using the correlation matrixes of anisotropic Gaussian directional derivatives, the particular corners were selected by the skeleton constraint, and the normalized distance between particular corners and the object centroid was taken as the corner descriptor. Then, the geometric moment invariants, affine moment invariants, and the Fourier descriptor of object boundary were extracted, respectively , and the scatter matrixes within and between classes for the four features were calculated. By taking the trace of sample scatter matrix as the weight, the four features were fused. Furthermore, the Independent Component Analysis (ICA) was carried out on the fused vector to obtain independent features. Finally, a Support Vector Machine (SVM) was adopted to complete the whole classification of the experiments. Experimental results show that the recognition accuracy of the proposed approach is higher than that of the signal feature approach by 10% averagely and that in the small training sample (10% of the total samples) condition still achieves more than 80% .It concludes that proposed algorithm meets the demand of theodolites for real-time object recognition.

For colored interference noise in digital ultrasonic signals at ultrasonic frequency band, an adaptive canceller was designed based on a transversal filter and the least mean square adaptive filtering algorithm. An adaptive filtering algorithm was proposed combining the fixed and adaptive step lengths. The proposed method could track automatically the changes of noise characteristics by adding a special probe to receive the environment noise without manually setting the parameters and the expected signals of the adaptive filter. By combining adaptive step method and fixed step method, the proposed method has good tracking and steady-state properties. Experiment results show that proposed method filters effectively out the colored noise located outside the frequency band of the target ultrasonic signal in real time and the signal-to-noise has improved up to 16 dB and the time complexity is O(n). The method has been successfully applied to gas ultrasonic flow measurement and filters out the colored noise in real time automatically and effectively without the manual intervention.

An improved Sage-Husa adaptive extended Kalman filter algorithm is proposed to ensure the precision and stability of calculating attitude angles of a multi-rotor Unmanned Aerial Vehicle(UAV) under the actual flight conditions, such as unknown and time-varied noise statistical properties, main disturbance source in vibration and attitude angles high dynamically changed. The algorithm uses attitude angle variance estimated by a gyroscope in real time to estimate system noise variance and only adopts an adaptive filter algorithm to estimate measurement noise variance on-line to ensure the precision and stability of filtering. Meanwhile, it introduces the criterion of filter convergence to restrain the divergence of Kalman filter through combining with a strong tracking Kalman filter algorithm. A flight experiment and corresponding analysis show that the root-mean-square errors of the pinch and roll angles estimated by the improved algorithm are 1.722° and 1.182°, obviously better than that of the conventional Sage-Husa adaptive Kalman filter algorithm. It concludes that the improved algorithm has strong adaptive ability, good real-time performance, high precision and reliable operation. It meets the need of multi-rotor UAV autonomous flight and can be applied to other navigation information measuring systems with high dynamic performance requirements if the parameters are modified appropriately.

The face recognition based on 3D facial data overcomes the difficulties sensitive to illumination and pose variations in 2D face recognition systems. However, the high computational complexity restricts its practical applications. To simplify the description for 3D face data, a novel strategy to map 3D face data to 2D ones, called 2D intrinsic shape description map, was proposed in this paper. With the strategy, each 3D facial surface was firstly mapped homeomorphically onto a 2D lattice which keeps the local geometrical features based on the constraint discrete conformal. Then ,a 2D intrinsic shape description map was obtained by combining 3D facial geometrical structure and appearance feature for simplifying 3D face representation and for verifying the recognition. The proposed strategy was compared to state-of-the-art 3D face recognition algorithms in the FRGC 2.0 and GavabDB database. The results show that the proposed strategy offers the rank-one rate of 90.6% when the pose change is greater than 60°, higher 5.9% than that of the existing method. Moreover, the single matching time is 7.89 s. As the strategy transforms the 3D face recognition into the 2D image recognition, it effectively reduces the complexity of data description and shows higher computation efficiency and robustness to a pose change.

Traditional gradient based image sharpness evaluation functions are sensitive to noise, which is easy to introduce more non-edge information and shows poor stability in practical applications. This paper analyzes the effect of the defocus of an optical imaging system on image sharpness based on the defocused model and proposes a improved sharpness evaluation method. The method uses the maximum gradient as the criterion of image sharpness.Then,it introduces the optimal threshold to distinguish the edge points and non-edge points to reduce the impact of the gradient of flat area and the noise in the image on evaluation results and to suppress the noise interference. The simulation experiments and actual test are performed and obtained results are compared with that of different traditional methods. It is verified that the improved method has better sensitivity and noise immunity, which is able to evaluate the sharpness of defocused image accurately and is suitable for auto-focusing in actual optical imaging systems.

As the accuracy of moving object tracking in video surveillance is disturbed by occlusion, camera moving and target appearance changing, an algorithm based on piecewise fusion weight and multi-strategy was proposed. Firstly, the piecewise fusion weight was constructed by combining the feature of object, background and candidate regions to obtain the likelihood image of object location. Then, the likelihood image was segmented with the spatial coherent and hysteresis threshold to suppress noise interference. Meanwhile, the object occlusion was determined and handled by analyzing the change of the piecewise fusion weight and enlarging the candidate area. Furthermore, the object scale was adaptively adjusted according to history and current scales. Finally, object information and background regions were dynamically updated to adapt to the object appearance and scene changing. Experimental results compared with other traditional methods show that the proposed algorithm is applicable to process the moving object tracking in low-contrast scenes in real time, and the average processing time for different video images is 10 ms, which means that the algorithm is suitable for the moving object tracking in complex scenes.

To meet the requirements of some injection simulation platforms for reality, a real adaptive topography optimization algorithm based on Real Time Optimally Adapting Mesh(ROAM) algorithm was proposed. By taking the terrain generated by ROAM as a base grid, a new integrated parameter Y was proposed, and a given threshold was compared with the Y parameter to determine whether the local splitting was implemented or not. The sharp features of the terrain were extracted from a vertex that satisfy the splitting conditions, and the local curve surface was splitted by Loop algorithm. Finally, a video stream was generated by rotation mapping algorithm in real-time roaming process and it was sent to the injection simulation system to be displayed by a Digital Visual Interface(DVI) display. Experimental results show that the average of roaming frame rate of proposed algorithm is 45.1303 frame/s and the peak frame rate is close to 50 frame/s, higher than that of traditional algorithm . Moreover, the obtained terrain could display on the DVI display on the injection simulation platform with an average of roaming frame rate of 45 frame/s, which satisfies the requirements of the injection simulation systems for the reality.

A cumulonimbus detection approach was proposed based on Multi Fuzzy Support Vector Machine(FSVM) by using a decision fusion strategy to solve the contradiction that adding more features will increase the accuracy of cloud classification while cause over fitting phenomenon due to high feature dimensions. Firstly, spectral features, the brightness temperature difference of multi-channels, first order histogram texture features, gray level co-occurrence matrix texture features and Gabor wavelet features were extracted from training cloud images to form a training sample set which contains 5 kinds of features. Then, five FSVM sub-classifiers were trained respect to each kind of feature. Finally, the output of each sub-classifier was fused by weighted decision in the output space to improve the detection accuracy of the cumulonimbus. Experimental results show that the proposed approach solves the over fitting phenomenon in cumulonimbus detection caused by the too high feature dimensions and can determine the weight of different features adaptively. The results also demonstrate that the accuracy is not only superior to each FSVM sub-classifier but also to the FSVM classifier trained by all the input features at once. The proposed approach is expected to be applied in the analysis of satellite cloud images.

To improve the segmentation precision of brain Magnetic Resonance(MR) imaging, a novel brain tissue automated segmentation method was proposed. Firstly, the merits and demerits of Gaussian mixture model and active contour model used for MR image segmentation were analyzed, and a new energy function was constructed through combining the probability density function of the Gaussian mixture model with the energy function of the active contour model. Then, the genetic algorithm and expectation maximization algorithm were used to get the parameter values of the probability density function. Finally, segmentation results were achieved through minimizing the novel energy function by using the level set method and the gradient descent algorithm. The experiment results clearly indicate that the segmentation accuracies of white matter and gray matter in brain tissue by the proposed method are increased by 6.73% and 14.07%, respectively as compared with that of the traditional methods. By using the area information and probability values of pixel points to drive the active contour curve, the proposed method automatically segments the brain MR image with high enough accuracy and improves the segmentation accuracy of brain MR images.