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This paper aims to enhance the machining accuracy of hybrid robots by treating the moving platform as the first joint of a serial robot for direct position measurement and integrating external grating sensors with motor encoders for real-time error compensation.

Initially, a spherical coordinate system is established using one linear and two circular grating sensors. This system enables direct acquisition of the moving platform’s position in the hybrid robot. Subsequently, during the coarse interpolation stage, the motor command for the next interpolation point is dynamically updated using error data from external grating sensors and motor encoders. Finally, fuzzy proportional integral derivative (PID) control is applied to maintain robot stability post-compensation.

Experiments were conducted on the TriMule-600 hybrid robot. The results indicate that the following errors of the five grating sensors are reduced by 94%, 93%, 80%, 75% and 88% respectively, after compensation. Using the fourth drive joint as an example, it was verified that fuzzy adaptive PID control performs better than traditional PID control.

The proposed online error compensation strategy significantly enhances the positional accuracy of the robot end, thereby improving the actual processing quality of the workpiece.

This method presents a technique for achieving online error compensation in hybrid robots, which promotes the advancement of the manufacturing industry.

This paper proposes a cost-effective and practical method for online error compensation in hybrid robots using grating sensors, which contributes to the advancement of hybrid robot technology.

This paper aims to investigate the preparation of Nano-Al₂O₃ lubricant, as well as the effect of surface modification of Al₂O₃ on friction and wear properties.

The chemical parameters such as the energy levels of the Highest Occupied Molecular Orbital, the Lowest Unoccupied Molecular Orbital and the Fukui indices of seven modifiers, including myristic acid myristyl ester, glycerol trioleate, acetyl monoethanolamine, docosanamide, Tween-60, dodecyl dihydroxyethyl amine oxide and sodium dodecyl sulfate (SDS), are calculated by using the Materials Studio software. Meanwhile, the adsorption energies of these seven modifiers on Al₂O₃ nanoparticles are also calculated. Based on the simulation results, SDS and Tween-60 were identified as the most effective surface modifiers. Modified lubricants were prepared with Al₂O₃ nanoparticles at varying concentrations (0.1–0.4 Wt.%). Their tribological properties, including the maximum nonseizure load (P_B) and the coefficient of friction (COF), were evaluated using a four-ball wear tester. The worn surfaces were analyzed by scanning electron microscopy and three-dimensional profilometry.

The results indicate that SDS improves both the extreme pressure and anti-wear performance of the lubricant. The lubricant achieves optimal performance when combined with 1.0 Wt.% SDS and 0.2 Wt.% nano-Al₂O₃. At this combination, the value of PB reaches 209 N, and the value of COF is approximately 0.072. Compared to the unmodified Al₂O₃ lubricant with a COF of 0.086, this represents a 23% reduction in COF.

Modified Al₂O₃ lubricants demonstrate superior lubrication performance and effectively reduce the COF, providing valuable insights for the practical application of nanolubricants.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0353/

This study aims to investigate the micro mechanism of macro rheological characteristics for composite modified asphalt.Grey relational analysis (GRA) was used to analyze the correlation between macro rheological indexes and micro infrared spectroscopy indexes.

First, a dynamic shear rheometer and a bending beam rheometer were used to obtain the evaluation indexes of high- and low-temperature rheological characteristics for asphalt (virgin, SBS/styrene butadiene rubber [SBR], SBS/rubber and SBR/rubber) respectively, and its variation rules were analyzed. Subsequently, the infrared spectroscopy test was used to obtain the micro rheological characteristics of asphalt, which were qualitatively and quantitatively analyzed, and its variation rules were analyzed. Finally, with the help of GRA, the macro-micro evaluation indexes were correlated, and the improvement efficiency of composite modifiers on asphalt was explored from rheological characteristics.

It was found that the deformation resistance and aging resistance of SBS/rubber composite modified asphalt are relatively good, and the modification effect of composite modifier and virgin asphalt is realized through physical combination, and the rheological characteristics change with the accumulation of functional groups. The correlation between macro rutting factor and micro functional group index is high, and the relationship between macro Burgers model parameters and micro functional group index is also close.

Results reveal the basic principle of inherent-improved synergistic effect for composite modifiers on asphalt and provide a theoretical basis for improving the composite modified asphalt.