No abstract

For the conveyor belt, variable material flow influences the energy efficiency of the speed control technology significantly. The fluctuation of material flow on the conveyor belt will lead to the detrimental vibrations on both the belt and the conveyor while the conveyor works at certain speeds. In order to improve the model inaccuracy caused by the uniform bulk material flow assumption in the current conveyor belt model, the paper establishes a high-precision dynamic model that can consider speed control of a conveyor belt under non-uniform bulk material transportation. In this dynamic model, a non-uniform bulk material distribution model is firstly proposed based on laser scanning technology. Then, a high-precision longitudinal dynamic model is proposed to investigate the dynamic behavior of a belt conveyor. Considering the micro-units of actual load on a conveyor belt, it can well describe the transient state of the conveyor belt. These models can be used to determine the optimal speed for safety and energy conservation in operation. Experimental results are used to validate the proposed dynamic model for analyzing belt mechanical behavior under non-uniform bulk material distribution on the belt. The results show that the proposed models can be used for optimizing the operating procedures of belt conveyor systems.

No abstract

Potential energy regeneration system, which shares an electrical energy storage device with power system, can further improve the fuel economy of hybrid construction machinery without much additional expense. However, the conventional potential energy regeneration system also results in poorer dynamic performance of actuators in comparison to throttle-governing system. In addition, the capacity of the regenerator should be large enough to avoid overload. Based on comprehensive consideration, this article presents a compound potential energy regeneration system that combines the regeneration device and throttle together. The regenerative torque is adaptive to load so as to keep the pressure drop over the throttle almost constant, and then the actuator can be governed by adjusting the opening of the throttle. The compound potential energy regeneration system is analyzed and evaluated using the frequency domain method and nonlinear simulation. Finally, experiments under different parameter conditions are carried out, and some useful design reference is provided. The simulation and experimental results show the effectiveness of the designed system as well as its control strategy.