Research And Design Of Six Free-degree Swaying Platform Control System Bsed On VxWorks

At present, six degree of freedom swaying platform has been used in pilot simulation, vibration platform, parallel manipulator, entertainment facilities, and other fields. Six degree of freedom swaying platform is a complex nonlinear system, and the servo control is the main element which can influence precision and response of the six degree of freedom swaying platform, and six degrees of freedom swing also needs good response speed in many other areas; The paper studies the control system of swing machine based on VxWorks: The real-time operating system VxWorks is used to enhance reaction speed of swaying platform, the adaptive inverse control is used to improve the response speed of the composite PID. The main contents are as follows:(1) The modeling of swaying platform: The control algorithm strategy research needs to create model, while the actual swaying platform has high cost of building and operating troubles, so the virtual swing platform model needs to be constructed; The dynamics modeling software ADAMS is used for modeling, which is not only simple but also relatively accurate. The input of established virtual swing model is the force, and the output is displacement. In order to match with the actual swing machine system better, the drive motor model need to be established as actuating device.(2) The strategy of hinge point space control: The kinematics reverse solution is which can obtain the length of six actuators through geometrical space analysis based on the position information of rocking motion platform. And the positive kinematics solution is which can use Newton-Raphson numerical iterative method to obtain position information of swing motion platform based on the length of six actuators. The control strategy includes the research on the compound PID control system of single cylinder.(3) The adaptive inverse control strategy: The adaptive inverse control on the basis of composite PID is used to improve the response speed of system in the paper because the response time of composite PID is long; In addition the composite PID often adopts the method of classical feedback to eliminate noise error object, while the adaptive inverse controller uses the inverse of transfer function of controlled object as controller, which can realize adaptive control for separate objects and noise disturbance, and improve the compound PID control strategy.(4) The software system of six degree of freedom swaying platform based on VxWorks: First of all, PC software which is developed by using the Labwindows/CVI manipulates the lower machine, and receives and displays the real-time information of the lower machine; And then using the Modbus communication protocol ensures the communication between the upper machine and lower machine; Finally the machine control system is designed based on the VxWorks operating system, which includs the system time, task communication, communication between PC software and the machine control system, and the control algorithm discretization based on the Vx Works system, whose results is verified compared with the Simulink result.