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An energy-saving control strategy for wheel loaders is proposed in this paper to address the issue of high energy consumption during their operation. The strategy is based on the intelligent identification of working stages, allowing for staged power matching and resulting in reduced energy consumption. Each work stage of the loader is identified by matching it to the main pump pressure waveform and actuator pilot pressure waveform. Using a sliding time window method, pressure waveforms from each working stage are subjected to feature extraction. A bidirectional long short-term memory neural network (BILSTM) algorithm is then used to establish an intelligent recognition model. Based on work stage identification, an energy-saving control strategy based on power matching is proposed for the shoveling stage of the loader, and the Grey Wolf optimization (GWO)-PID algorithm is utilized for control parameter tuning. Finally, the effectiveness of the energy-saving control strategy based on work stage identification is verified through experiments. The research results indicate that the BILSTM recognition model outperforms other models with a recognition accuracy of 96.1%. The optimal time window width is 0.6 s, and the proposed energy-saving control strategy achieves a fuel-saving rate of 6.81%. This method provides feasibility for reducing energy consumption in construction machinery and achieving energy-saving and carbon-reduction goals. [ABSTRACT FROM AUTHOR]

Low‐cost and efficient large‐scale triboelectric nanogenerator (TENG) is considered as the new scheme for distributed mechanical conversion or renewable energy utilization. An extremely popular all‐inorganic lead‐free double perovskite Cs2AgBiBr6 (CABB) has emerged as extraordinary potential material in triboelectric semiconductors' substitution, overcoming high‐impedance limitations associated with organic‐polymer‐insulator based materials. In this study, assembled by the certified available positive frictional material CABB, TENG with sandwiched structure of ITO/compact‐TiO2/mesoporous‐TiO2/CABB – the poly‐tetra‐fluoroethylene/Al exhibits appropriate performance on environmental stability and output capacity for which structure can impede charges decay. Fabrication process comparison shows that as an inexpensive large‐scale functional films preparation method, sprayed CABB TENG with brilliant relative dielectric constant and work function difference possess more distinguished output characteristics. This is confirmed by higher open‐circuit voltage of 105 V, larger short‐current density of 2.45 mA m−2 at 0.25 Hz motion parameter, and more abundant output power density of 0.76 W m−2 under 10 Hz. Further study confirms that both higher frequency and larger contact‐area are conducive to total output power, while terminal charging speed is inversely or positively proportional with capacitance or mechanical frequency. Final physical display effect of sprayed CABB TENG lights up at least 53 commercial yellow‐LEDs, holding decent energy conversion ability. [ABSTRACT FROM AUTHOR]

• Proposes a multi-stage determination method for excavator working points that considers engine fuel consumption, hydraulic pump efficiency, and load fluctuation, overcoming limitations of traditional methods. • Introduces a comprehensive evaluation model for working point determination that integrates fuel consumption, hydraulic pump efficiency, and load variability, offering a more holistic approach. • Utilizes experimental data to inform the determination of engine working points, ensuring practical relevance and applicability. • Employs weight parameters to adjust the importance of fuel consumption and load fluctuation in the working point optimization process, allowing for tailored engine performance improvement under varying operational needs. In view of the problem that the traditional working point determination method only considers the engine fuel consumption and does not consider the hydraulic pump efficiency and load fluctuation in the process of the working point stability control of an excavator engine, a simple and feasible, experimental data-driven, multi-stage determination method of excavator working point based on the comprehensive evaluation model is proposed. In this paper, the comprehensive evaluation model of working point torque with weight parameters is established at different working stages under the rated speed in a phased way. The results show that this method can determine the working point torque at different working stages, and reduce engine fuel consumption and load fluctuation based on ensuring the efficiency of the hydraulic pump. The lowest engine fuel consumption can be reduced by 7.09%, and the lowest load fluctuation can be reduced by 17.8%. In addition, by modifying the weight parameters, we can emphasize the fuel consumption and load fluctuation of the engine according to their importance, to achieve the determination of working points under different requirements. This approach also provides a new idea for optimizing the working point of construction machinery. [ABSTRACT FROM AUTHOR]

• Revealed the damage zone characteristics of different tools penetrating rocks. • Identified the key factors of energy transfer efficiency in impact rock breaking. • Investigated the key influencing factors of the dynamic force-penetration curve. • Proposed a prediction formula for penetration force considering the tool shape. • Evaluated the proportion of energy used for rock cracking. The energy transfer efficiency and damage characteristics are the theoretical basis for the selection and optimization of hydraulic impact hammer tools. In this paper, quarter three-dimensional models of the piston-tool-rock system are established based on the continuum and discontinuum element method. The incident and reflected stress waves and rock damage characteristics obtained from the simulation model are in good agreement with experimental and theoretical results. The effects of piston impact velocity, tool shape, rock strength, confining pressure and repeated impacts on rock damage zone and energy transfer efficiency between tool and rock are analyzed. The force-penetration curves and penetration coefficients under different impact velocities, rock strength, and confining pressure conditions are obtained. The results illustrate that the energy transfer efficiency and penetration coefficient increase with the increase of rock strength, confining pressure and tip area of tool, but decrease with the increase of impact velocity. Based on the simulation results, a prediction formula for penetration force with consideration of the shape of the tool tip is proposed and the calculation accuracy is verified. Finally, the proportion of energy actually used for rock fracturing is analyzed. [ABSTRACT FROM AUTHOR]