The Method Research On Complementary Sliding Mode Control For Active Heave Compensation Of Deep Sea Cranes

With the implementation of marine strategy,marine equipment is one of the important links to realize the goal of marine resource.Cranes is one of the most widely used tools in marine equipment.Under the influence of the marine environment,the violent vertical movement of the lifting point has a serious impact on the offshore operation of the crane,resulting in the fracture of the wire rope or umbilical cord.Active heave compensation can weaken the influence,so this paper stars with the control method of active heave compensation of deep-sea cranes,and realizes the safe operation of crane in deep-sea environment.Firstly,the mathematical model of deep-sea crane is built by using ocean wave dynamics and Newton's second law.The parameters associated with the state variables are expressed by function expression,and transformed into state space equation,which paves the way for the design of control system to realize active heave compensation.Secondly,the active heave compensation is realized by eliminating the disturbance of the crane,the disturbance of the deep-sea crane is divided into matched disturbance and unmatched disturbance.Based on the state space equation,a complementary sliding mode controller is designed to eliminate the influence of the matched disturbance on the load;for the unmatched disturbance,the extended disturbance observe is used to observe the unmatched disturbance and feed back to the complement sliding mode controller.Thirdly,aiming at the unmeasurable cable strain of cranes,an extended state observer is designed to observe the cable strain in real time and feedback it to the improved complementary sliding mode controller to realize active heave compensation.The high power nonlinear function is introduced into the extended state observer to make the observation error smaller than that of the linear observe;In order to reduce the output amplitude of the controller and improve the control accuracy,the anti hyperbolic sine function is introduced to design the complementary sliding mode of the system state.The simulation results verify the effectiveness of active heave compensation.Finally,it is known from the previous chapter that the sliding mode factor determines the position of the complementary sliding surface,and has a great influence on the chattering and load displacement tracking error of the control output.Therefore,a complementary sliding mode control method based on reinforcement learning is designed.In the design process of complementary sliding mode controller,the gradient descent algorithm of reinforcement learning is used to optimize the control parameters and realize the online adjustment of parameters.In the adjustment process,the control output chattering is used as the evaluation function of reinforcement learning,and the load tracking displacement error and control output chattering are taken into account,so that the control system has better adaptability.