Under the effect of different process parameters, the temperature field inside the thermoplastic fiber is very complex and directly affects the fusion quality between the resins. Considering the heat transfer behavior of thermoplastic fiber polyether ether ketone (PEEK) as the research object, a mathematical model of heat transfer in the thermoplastic composite fiber placement with the relevant boundary conditions was established. Ansys Parametric Design Language (APDL) was used to generate the finite element model and simulate the transient process, not only to explore the influence of various process parameters on the temperature field, but also to build an online temperature field measurement system. The influence rules of placement process parameters and mold initial temperature with respect to the temperature field in the first layer were obtained. Combining the relationship between heating temperature and placement speed, when the first layer was laid, the placement process temperature could be quickly reached by low speed and high temperature. The temperature data were collected by the online detection system. Compared with the temperature data from the simulation, the error was below 8%, which verified the correctness of the heat transfer model. The academic research results will lay a theoretical foundation for the thermoplastic fiber placement.

This paper reports a systematic analysis of a load sensing system with hydro-mechanical pressure compensation and independent metering. In contrast to a conventional spool valve controlled load sensing system, the proposed load sensing system is characterised by both meter-in and meter-out pressure compensation. Quasi-static behaviour analysis is applied to three distinct load sensing systems: the meter-in pressure compensation system (MIPCS), meter-out pressure compensation system (MOPCS), and pressure compensation load sensing system (PCLSS). The energy usage equation shows that minimising pump supply pressure is the only way to ensure high energy saving efficiency; proper opening modes between the meter-in and meter-out orifices of the MIPCS and MOPCS are also obtained by deducing and analysing appropriate equations. Systems parameters are then kept constant as the pump supply pressure of the three systems are compared by varying the external force. Comparison results show that the pump supply pressure of both the MIPCS and MOPCS are lower than that of PCLSS, and that the optimal metering pressure compensation method is dependent on the working mode. Taken together, the results show that a load sensing system with independent metering offers more significant energy savings than the traditional load sensing system.

This article studies the energy-saving performances of the independent metering system with pressure compensation for excavator’s manipulator. Compared to the electro-hydraulic pressure compensation method, the hydro-mechanical pressure compensation method is commonly applied in the conventional load-sensing systems as it reacts directly and rapidly. Independent metering system has more controllability, because meter-in and meter-out orifices are decoupled. In this study, the hydro-mechanical pressure compensation method is adopted in the designing of independent metering system for excavator’s manipulator. According to the demand forces and velocities of the cylinders in the excavator’s manipulator part, the pressure compensation independent metering control blocks of boom, arm, and bucket are completely designed. The most energy-efficient manner of opening the meter-in and meter-out orifices for proportional output velocity has been obtained by quasi-static behaviors’ analysis. The excavator’s manipulator virtual prototype model, the conventional load-sensing system model, and pressure compensation independent metering system model are built. The system parameters are kept as consistent values, and the energy consumptions of the two systems are compared in the simulations. The comparison results indicated that the pressure compensation independent metering system offers more significant energy savings than the conventional load-sensing system when the system is steady.

As a representative of multi-functional engineering machinery, the excavator is irreplaceable in the field of engineering construction. To autonomously control the excavator bucket, it is essential to control the position of the bucket hydraulic cylinder. As a consequence of the problem of position tracking control spawned from external disturbance and other factors in the self-mining servo system of excavators, a strategy of sliding mode backstepping control based on the particle swarm optimization algorithm and neural network disturbance observer (PSO-NNDO-SMBC) was recommended accordingly. Meanwhile, the complex disturbance was estimated online and compensated for by the system control input by the universal approximation property of the neural network disturbance observer (NNDO). Afterwards, the uncertainty of control parameters was optimized by the particle swarm optimization algorithm (PSO) and was fed back to the controller parameter input end. Afterwards, a co-simulation model of MATLAB/Simulink (MATLAB2023b) and AMESim (Simcenter Amesim 2304) was established for simulation analysis, and a test bench was set up for comparison and verification. As proven by the experimental results, PSO-NNDO-SMBC possessed strong anti-interference ability. In contrast to the sliding mode backstepping control based on the particle swarm optimization algorithm (PSO-SMBC), the maximum displacement tracking error was lowered by 50.5%. Furthermore, in comparison with the Proportional-Integral-Derivative (PID), the maximum displacement tracking error was decreased by 75.2%, which tremendously optimized the control accuracy of excavator bucket displacement tracking.