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This study aims to realize the constant force grinding of automobile wheel hub.

A force control strategy of backstepping + proportion integration differentiation (PID) is proposed. The grinding end effector is installed on the flange of the robot. The robot controls the position and posture of the grinding end actuator and the grinding end actuator controls the grinding force output. First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. Finally, the feasibility of the proposed method is verified by simulation and experiment.

The simulation and experimental results show that the backstepping + PID strategy can track the expected force quickly, and improve the dynamic response performance of the system and the quality of grinding and polishing of automobile wheel hub.

The mathematical model is based on the pneumatic system and ideal gas, and ignores the influence of friction in the working process of the cylinder, so the mathematical model proposed in this study has certain limitations. A new control strategy is proposed, which is not only used to control the grinding force of automobile wheels, but also promotes the development of industrial control.

The automatic constant force grinding of automobile wheel hub is realized, and the manpower is liberated.

First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. The nonlinear model of the system is controlled by backstepping method, and in the process, the linear system composed of errors is obtained, and then the linear system is controlled by PID to realize the combination of backstepping and PID control.

The aim of this paper is to study the effect of heat treatment temperature and time on the corrosion behavior of ductile iron in 0.5 M NaCl and 0.5 M H₂SO₄.

Ductile iron samples of known composition were austenized at temperatures 800°C and 850°C, and austempered at 300°C and 350°C for periods of 30, 45 and 60 min to convert them to austempered ductile iron (ADI). The corrosion behavior of these ADI samples in 0.5 M NaCl and H₂SO₄ was measured using the conventional weight loss method. The metallographic examination of the samples was carried out to study the morphology of their corroded surfaces.

Ductile iron is susceptible to corrosion in both acidic and chloride media, while attack by acid media is mainly at the grain boundaries, that from the chloride is pitting. The corrosion behavior of the material is affected by the compositional structures of the materials as well as the austempering temperature and time it was subjected to.

Ductile iron has the potential to replace costlier materials in many engineering and structural applications.

The results revealed that the corrosion of ADI in both acidic and chloride media were strongly dependent on the structure of the material, which in turn was affected by the austempering temperature and time.