Xinxing Pipes International Development (China)

With the increase in tightening of carbon neutral policies, electric new energy vehicles have become a top priority in the development of the automotive industry. The integrated electric vehicle wheel (hub motor) can effectively optimize the vehicle structure and reduce the weight of the vehicle and reduce the energy consumption. At the same time, the feature that four tires can be driven separately is also conducive to the application of various new control algorithms. In this paper, a generalized adaptive PID control is experimented with the speed control of the hub motor, and a fuzzy control-based variable step method is proposed for the overshoot or even runaway problem caused by the inertia of the hub motor in the process of adaptive PID control. Experiments have demonstrated that this method can effectively reduce the amount of overshoot triggered by adaptive control and shorten the regulation time into a steady state.

In this paper, aiming at the trajectory tracking problem of the nonholonomic mobile robot with static obstacles, a simultaneous trajectory tracking and obstacle avoidance method based on the model predictive control (MPC) is proposed. First, a quadratic cost function is calculated to obtain the optimal tracking error in the trajectory tracking controller. Then, the obstacle avoidance region is established, and the optimal obstacle avoidance direction is determined according to the location parameters of the robot, the reference trajectory and obstacles. Finally, simulation results are provided to show the effectiveness of the control method.

The metallurgical composite bimetallic tube, Incoloy825/X60, has been manufactured by a novel centrifugal casting plus extrusion compound technique. Based on the Incoloy825/X60 bimetallic tube, the limiting inner pressure and stress distributions were investigated by the finite element analysis software ABAQUS. The results indicate that the pressure-resistant capacity of the metallurgical composite bimetallic tube is equivalent to the internal metal in elastic state while the limiting inner pressure is much larger than the single metal tube with the same sizes in plastic state. The pressure-resistant capacity of the metallurgical composite bimetallic tube has increased more than two times compared with the external metal tube because of the transition layer which has a complete metallurgical bonding.

Based on the finite element analysis software ABAQUS, the CT specimens of bimetallic material and the metallurgical composite bimetallic pressure tube with axial crack were simulated on the fracture mechanical properties, after that the crack growth residual strength and the plastic failure stress of the metallurgical composite bimetallic pressure tube model were obtained. The results indicate that the crack growth residual strength generates near the crack tip and the crack growth residual strength of the pressure tube model is smaller than the CT specimens. Meanwhile, the plastic failure stress values obtained from the CT specimens and the pressure tube model are basically consistent with the theoretical calculative values. With the crack depth a increasing, the plastic failure stress values will be reduced. For the same crack depth, the plastic failure stress values of the pressure tube model are slightly lower than the CT specimens and the theoretical calculative values.