Research On The Design Of Variable Load Stable Platform And Its Control Technology

The variable-load stable platform is suitable for experiments on moving vehicles such as aircraft,ships,vehicles and so on that require the stability of the visual axis.Because different types of loads can be changed to adapt to different detection tasks,there is no need to set up multiple stable platforms,which has high economic efficiency.And convenience.This paper focuses on the variable load stable platform structure design and related control issues,completes the complete machine design of the variable load three-axis stabilized platform and the finite element analysis and optimization of the complete machine structure,and studies the stability control method of the variable load three-axis stabilized platform.In view of the large differences in the load field of view and mass distribution of the variable load stable platform,3D solid modeling is carried out in Solid Works,and the stable platform is compatible by replacing the counterweight to balance the mass distribution and reserve the driving torque margin of the actuator.For two types of loads,the load compartment,follow-up shafting,mechanical limit mechanism and waterproof mechanism of the variableload three-axis stable platform are designed,and the overall design of the variable-load threeaxis stable platform is determined.For problems such as large structural parts and unclear modal characteristics,the main structural parts of the variable-load three-axis stable platform and the whole machine were analyzed in ANSYS Workbench,and topology optimization,statics,and transient dynamics were carried out.Through analysis and modal analysis,the strength and stiffness characteristics of the main structural parts were checked,and the vibration characteristics of the variable load stable platform before and after topology optimization were obtained.Regarding the stability control of the variable-load three-axis stable platform,analyze the carrier disturbance and the coupling between the DC torque motor in the coordinate system,establish a kinematic model in MATLAB/simulink,and combine the differences in the dynamic characteristics of the two loads to build three DC torque motor models with different loads under two shaft systems.On this basis,according to the principle of simple structure,high realtime performance and good stability effect,a double closed loop control system of speed stability loop and position stability loop is designed,and PID controller and fuzzy PID control are designed in the position stability loop.According to the analysis of the stability effect,the influence of the moment of inertia difference on the stability control of variable load is obtained.The simulation results in ANSYS Workbench show that the strength and stiffness of the smaller mass structure after the topology optimization design meet the design requirements.The simulation result in MATLAB/simulink is: when the carrier disturbance angular velocity amplitude is 20°/s(that is,0.35rad/s),the maximum angle stability error of the variable load three-axis stable platform using the traditional PID controller is 0.28 mard,The maximum value of RMS(root mean square value)is 0.12 mard,the maximum angle stability error of the variable load three-axis stabilized platform using fuzzy PID controller is 0.17 mard,and the maximum RMS value is 0.056 mard.The simulation results show that the fuzzy PID control algorithm is better than the PID control algorithm in terms of adjustment time.The dynamic performance and anti-interference ability of the system have been significantly improved,and it has better adaptability to the two types of variable load three-axis stable platforms.