Inspired by carangiform fish with a high-aspect ratio of the caudal fin’s up-down swing, but also by dolphins with a similar caudal fin’s left-right swing, a robotic fish with a spatial oscillating rigid caudal fin is implemented to optimize propulsion and maneuverability, whose orientation could be transformed to any position of a taper domain. First, three steering-engines were adopted to make the conceptual prototype, and an experimental apparatus for measuring thrust, lift forces, lateral forces and torque was developed. Then, three comparison experiments, respectively corresponding to the three modes of cruise, diving and maneuvering in random space, were conducted to imitate bionic fish’s hydrodynamics. The comparison results of the experiments proved that propelling and maneuvering in any direction could be realized through changing the orientation of the spatial oscillating rigid caudal fin.

A slight improvement in the transmission efficiency of the herringbone star gear train in a GTF has a great impact on the fuel economy of the engine. Here, the influencing factors of gear train efficiency were studied from the perspective of gear train composition, and the efficiency calculation model of the split star gear train, including the load-sharing coefficient, was established. Based on the efficiency calculation model, the mechanical relationship affecting the load distribution of the split star gear train, and the influence of installation error on the power split of the gear train, were studied. The effects of torque and installation error on the load coefficient of the gear train were studied using dynamic analysis software, and the efficiency of the gear train under multiple working conditions was verified and analyzed.

Deformation stress of a flexspline under the action of a wave generator directly affects the service life of the flexspline and meshing quality of meshing pair. This study proposed a new deformation model for a flexspline, which incorporates forced deformation in the working area and free deformation in the non-working area, keeping the deformation shape unchanged during rotating. Based on this assumption of a deformation model, the mathematical model is further established, and the design approach of a cam wave generator is developed with the deflection curve of the ring structure. Then, a sample design with a double eccentric arc cam wave generator based on this deformation model is developed and analyzed in FEM. The results show that the deformation stress of the flexspline can be improved by relaxing the forced deformation in the non-working area, and the selected deformation shape can also remain unchanged during rotating. Moreover, the stress distribution and the maximum stress value could be improved with the variation of the combination coefficient, especially for the wrap angle.

The deformation shape and mechanical property of flex-gear greatly affect the meshing accuracy and service life of harmonic drive, and the stress wave generator plays a decisive role in the deformation shape and mechanical properties of the flexible gear. The investigation on deformation of the flex-gear around the major axis is developed with comparative analysis with three kinds of traditional and commonly used wave generators. Based on the influence of the deformation around the major axis on meshing accuracy and service life, the eccentric arc cam wave generator improved by transition curve for controlling the deformation shape and reducing the deformation stress is developed. Considering the achievable flexibility of spiral with smooth curvature change rate, the contour of the compound curve cam wave generator with arc and spiral is proposed. The deformation of the flex-gear under the influence of this compound curve cam and the standard elliptic cam is further comparative analyzed. The conclusion shows that this compound curve cam can indeed reduce the deformation stress in the meshing area by increasing the meshing width, and correct deformation shape can also be gained by shape control on the whole circumference of the flex-gears neutral layer.

In the research on key technology of radiation-curing coil steel coating, it is necessary to evaluate the coating stability of radiation-curing coil steel coating materials. In this paper, a roll coating-simulation test equipment is proposed to test coating status. Considering the operational stability of the equipment, dynamic vibration response analysis and stability analysis of the roller-coating process are performed on the equipment. The test results show that the rotor vibration of the designed roll coating-simulation test equipment meets the requirements of rotating machinery, and the coating thickness remains stable under the vibration condition, which satisfies the working condition of the test equipment.

The deformation of the flexspline and the meshing quality are largely determined by the profile of a wave generator. The wave generator with a combined profile can effectively reduce or improve the deformation stress and strain of the flexspline for improving the transmission efficiency and reducing wear or noise. In this paper, in view of the facts that conic is originally cut out of the cone and different conic curves are easy to transform, a design concept of the curve cam wave generator based on the conic curve is proposed. Firstly, the combined principle, constraint conditions, and mathematic model of the curve cam generator based on the conic curve are established. Secondly, the deformation theory of the flexspline acted by the curve cam wave generator with conic curves has been developed, and finite element analysis on stress and strain of the flexspline compared with a standard elliptic wave generator has been carried out. Finally, a cam wave generator combined with the circle and ellipse as a sample has been developed and manufactured. Circumferential strain test has been further carried out by a static strain gauge to verify the strain characteristics of the flexspline acted with the circle and ellipse combined cam wave generator. The FEM results show that, in the meshing area of the flexspline, the maximum equivalent stress of the flexspline under the action of the arc and the ellipse wave generator is about 93 MPa, which is 36.3% lower than the maximum equivalent stress of the flexspline under the action of the standard ellipse which is 143 MPa. The experimental results show that the fitting curve of the experimental results fits well with the finite element analysis curve.