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In order to further improve the stability and accuracy of the pouring trajectory of the heavy-duty casting robot during the pouring operation, a new hybrid four-degree-of-freedom heavy-duty casting robot is taken as the research object, and a trajectory planning method based on the synthesis of the fifth-order polynomial and the sinusoidal acceleration motion law is proposed. The degree-of-freedom of the actuator is calculated by the topological structure theory of the robot mechanism, and the position of the parallel mechanism is solved by the closed-loop vector method, the kinematic position equation of the hybrid mechanism is derived according to the equivalent method and the geometric method. The trajectory planning of the robot is carried out by combining the fifth-order polynomial and the sinusoidal acceleration motion law. The Adams software is used to simulate the trajectory motion of the robot end, and the parameters obtained by the theoretical solution are verified. The results show that the trajectory based on the combination of the fifth-order polynomial and the sine acceleration motion law is smoother and more natural than the fifth-order polynomial, and the maximum speed of the robot end is reduced by 14%, avoiding the vibration due to excessive speed fluctuations.

The work aimed to study the effect of thermoplastic polyaryletherketone (PAEK) on the curing kinetics, thermal stability and erosive wear performances of bismaleimide (BMI) resin blends. Toughened bismaleimide blends were fabricated using the allyl compound modified bismaleimide resin prepolymer as matrix and PAEK as a toughening agent by blending method. The modified PAEK/BMI blends were characterized and analyzed using the fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), the swirling water jet erosive wear apparatus, scanning electron microscope (SEM) and three-dimensional surface profilometer. No obvious glass transition was observed for PAEK modified BMI blends in the temperature range of 50–350°C. In addition, the char yields (Y c) and the heat-resistance index (T HRI) of the PAEK/BMI blends were affected by PAEK addition. The kinetic parameters, such as the activation energy and the pre-exponential factor of the PAEK/BMI blends were also higher than that of unmodified BMI blends, indicating that the incorporation of PAEK could promote the curing reaction of the epoxy resin without changing the curing mechanism. The erosive wear rate increased with the addition of PAEK especially when the mass fraction of PAEK was 10 parts per hundred of resins (phr.). These results suggested that the thermal stability of the PAEK/BMI blends was significantly enhanced while the erosive wear resistance decreased by introducing the PAEK. [ABSTRACT FROM AUTHOR]