Abstract: With the economic globalization and the rapid development of enterprises, issues related to petroleum leakage, food safety and environmental pollution have become more and more severe, directly affecting human living environment, social harmony and the development of enterprises. At the same time, many listed companies begin to focus on releasing reports with respect to social responsibility, sustainable progress and environmental protection. Using the social responsibility report of Petro China Co. Ltd. as a case, this paper analyzes the current situation of social responsibility information disclosure of China's petroleum enterprises and existing problems in order to provide suggestions for improving the social responsibility information disclosure quality of petroleum enterprises.Abstract: With the economic globalization and the rapid development of enterprises, issues related to petroleum leakage, food safety and environmental pollution have become more and more severe, directly affecting human living environment, social harmony and the development of enterprises. At the same time, many listed companies begin to focus on releasing r...Show More
Abstract: A second-order hierarchical fast terminal sliding mode control method based on disturbance observer (DOSHFTSM) is proposed for a class of fourth-order underactuated systems. In the first step, the fourth-order underactuated system is divided into two subsystems, and the integral sliding surface is designed for each subsystem. Then, the first-order fast terminal sliding surface is defined by using the integral sliding surface and its derivatives of each subsystem, and the switching control items of the system are designed according to the first-order fast terminal sliding surface of the subsystem. Secondly, the second-order sliding surface is designed by using the first-order fast terminal sliding surface of each subsystem. On the premise of ensuring the stability of Lyapunov, the switching control term is designed by using the variable coefficient double power reaching law to eliminate the system jitter. Finally, based on the principle of hyperbolic tangent nonlinear tracking differentiator, a hyperbolic tangent nonlinear disturbance observer (TANH-DOC) is designed to estimate the uncertainties and external disturbances of the system and compensate them to the sliding mode controller to improve the robustness of the system. The stability of the system is proved by using Lyapunov principle. The validity of this method is verified by numerical simulation and physical simulation of inverted pendulum system.Abstract: A second-order hierarchical fast terminal sliding mode control method based on disturbance observer (DOSHFTSM) is proposed for a class of fourth-order underactuated systems. In the first step, the fourth-order underactuated system is divided into two subsystems, and the integral sliding surface is designed for each subsystem. Then, the first-order ...Show More
