Research On A Multi-degree-of-freedom Simulation Motion Platform Control System

The exploration of hydrate resources in China's major sea areas gradually enters the etailed investigation and trial mining stage,the accuracy requirements for exploring the spatial distribution of seabed hydrate ore bodies are also increasing.The deep towed system is an important tool of detecting seabed resources,and its design requirements are also constantly improving.Due to the complexity of the laying and recycling process,the conventional weak positive buoyancy towed body is not conducive to the development of offshore operations;Compared with the weak positive buoyancy towed body,the gravity-type towed body is simple to operate and maintain,and it can work in more complicated sea areas,the stability of the gravity-type towed body is poor due to the absence of buoyant material.Therefore,this paper analyzes and tests the stability of the gravity-type towed body in the submarine motion.Because the seabed environment is too complicated,this paper only studies and analyzes the influence of the towed body on the towed cable without considering other interference factors.A multi-degree-offreedom simulation motion platform is designed and developed to simulate the motion of the towline,which is used to test the performance of the tow body and the stability of underwater motion,and to help the design of the tow body.Firstly,the motion model of the towed cable is established,and the force of the towed cable under water is analyzed.On the basis of simplification,the motion state simulation of the towed cable at towed point(where the towed cable is connected with the towed body)under different conditions is completed by ANSYS.According to the analysis of the motion state of the towed cable at towed point,the STM32 is used as the core multi-degree-of-freedom simulation motion platform control system to simulate the motion state of the towed cable at towed point under different conditions.The related peripheral circuits are developed,including communication module,power supply module and SWD debug circuit,stepper motor drive interface circuit,encoder interface circuit,etc.Because the body of the tow is too large and difficult to experiment,a towed model with a volume ratio of 1:10 is designed.The towed body is identical in structure and material to the tow body and will be used in subsequent simulation experiments.Based on the designed hardware circuit,the software development was carried out for the requirements of different motion states of the towed cable at towed point.The characteristics of embedded motion control system were considered comprehensively.The upper computer software was designed with Visual Studio,which realized the configuration of serial port parameters,parameters setting when simulating different motion states of the towed cable and the motion state feedback of the six axes of the motion controller;the motion controller software is designed by Keil to realize the trajectory planning and closed-loop control of each axis of the controller.In order to make the axes of the towed cable simulation motion control system run smoothly,the Scurve planning is studied.The fuzzy adaptive PID control algorithm is used to realize the closed-loop control of six axes of the towline simulation motion control system.The experimental results show that the simulated motion platform control system can accurately simulate different motion states at the tow point of the towed cable.