To improve the stability and accuracy of quintic polynomial trajectory tracking, an MPC (model predictive control) and fuzzy PID (proportional-integral-difference)- based control method are proposed. A lateral tracking controller is designed by using MPC with rule-based horizon parameters. The lateral tracking controller controls the steering angle to reduce the lateral tracking errors. A longitudinal tracking controller is designed by using a fuzzy PID. The longitudinal controller controls the motor torque and brake pressure referring to a throttle/brake calibration table to reduce the longitudinal tracking errors. By combining the two controllers, we achieve satisfactory trajectory tracking control. Relative vehicle trajectory tracking simulation is carried out under common scenarios of quintic polynomial trajectory in the Simulink/Carsim platform. The result shows that the strategy can avoid excessive trajectory tracking errors which ensures a better performance for trajectory tracking with high safety, stability, and adaptability.

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Non-circular crossed gear can be regarded as the general form of the single stage gear, which can be converted into hypoid gearing, non-circular bevel gearing, non-circular external gearing, and non-circular internal gearing with specific parameters. This paper established its mathematical model, deduced equation of its axode, and put forward a new method of tooth profile generation with introduction of relative velocity. In term of the theory above, the 3D model of a pair of conjugated gears was built, and its output angular velocity was obtained in analysis of ADAMS. Finally, the physical prototype of the gearing was developed and output angular velocity was measured as well. Both the simulation and measurement results show the motion is in good condition, which confirms the correctness of the theory and algorithm.

To explore the correlation between vibration and power consumption of angular contact ball bearings, the evaluation of power consumption was merged into the original nonlinear dynamic model of ball bearings and this model was validated by the experimental method. On this basis, a comprehensive analysis of vibration and power consumption of ball bearings was conducted, then, the variations in the power consumption and vibration at different numbers of balls and groove curvature radii were studied, again, their optimal combinations were determined to attain the acceptable power consumption, dynamic stability and vibration in the bearing system. The corresponding results illustrate that reducing the maximum number of balls by one or two can obtain the good dynamic performance of friction consumption, dynamic stability and vibration of ball bearings, besides, the combination of inner and outer groove curvature radii should both strengthen contact loads and effectively guide the motion of the ball to get the favorable comprehensive performances.