The volumetric error of a measurement-processing integrated machine tool was studied by using a complicated surface workpiece grinding machine as a special example. The model of volumetric error was established by using homogeneous transformation matrices, and the effect of volumetric error on coordinate transformation between the measurement and the processing work station was analysed. Various error components of the machine tool were measured with a laser interferometer and an electronic level, and the volumetric error was compensated by external software. With a ball bar system and grinding experiments, the volumetric position accuracy was tested after compensation. The experiment results illustrated that both the volumetric position accuracy and machining precision were improved dramatically after compensation.

Normal vector measurements of the machining point and attitude adjustments of the end effector are key aspects to meet the technological requirements of hole verticality in auto-drilling and the residual wall thickness in mirror milling. In this paper, a surface normal on-machine measuring method using an EC sensor array is proposed. The influences of the object surface inclination and the sensor array arrangement on the performance of EC displacement sensors were investigated, and the sensor measuring errors from coupling interference were effectively eliminated. Moreover, a practical calibration algorithm was established in which the positions of the EC sensors in a normal vector calculation model were accurately corrected. The feasibility of the measuring method was validated through a calibration experiment, as well as a measurement experiment based on the calibration results. The accuracy of a normal vector measurement is improved when applying the accuracy compensation and position calibration algorithm of an EC array to engineering practices.

The overall performance of large aerospace vehicles is determined to a great extent by the wings structure of aircrafts. In order to prevent wings vibration due to external interference, schemes of combined fuzzy-PID and fuzzy adapt PID controllers are proposed based on flexible beam structure. The MATLAB simulation model demonstrates that the proposed controllers not only has good dynamic characteristics, but also reduce the vibration effect greatly caused by external disturbance, which lay the foundation for the active vibration control of aircraft wings.

To characterize the residual stress distribution is very crucial for workpiece fatigue lifetime and structural integrity assessment. An energy-based residual stress field reconstruction approach using limited measurements is proposed. Firstly, the Ferguson spline interpolation technique is employed as the stress interpolation base of the 2-order stress tensor. Then, an initial stress field can be reconstructed using the overall boundary conditions by minimizing strain energy. Further, the stress distribution is modified according to strain compatibility equation. At last, a typical stress unit from the artificial stress field constructed by FEM, was picked up as an input set to verify the validation of the developed model and algorithm numerically. It was demonstrated that the energy-based scheme was efficient and reliable to reconstruct the residual stress field from limited measurements.

The electric thickness of the semi-finished radome may not meet the requirement for the electromagnetic performance because it varies with both the geometry thickness and the electric inductivity of the radome. One way to obtain the required value of the electric thickness is to compensate the electric thickness error by modifying the wall thickness of the radome. To this end, a grinding machine is developed and applied to precisely grind the inner surface of the radome. In order to ensure the grinding precision, it is important to keep the grinding machine under a stable, rapid and precise control. In this paper, a compound control strategy, which is a combination of the cascade control of 3-loop, the feedforward control and the PID algorithm, is proposed to realize a highly precise and reliable control over the grinding machine. Moreover, the architecture of the control system, the algorithm of the main controller based on DSP technology and the method of adjusting parameters are also introduced. It is shown that this compound control strategy has the advantages of high control accuracy and strong anti-jamming ability, being effective and applicable.