Construction Of Computer Control System And Control With Consideration Of Actuator Saturation For A Hybrid Conveying Mechanism

The existing auto electro-coating conveying system is mostly with the cantilever beam structure, which has heavy load, large load capacity and poor flexibility level. This research group, funded by the national natural science foundation project(51375210), takes the advantage of the characteristics of the hybrid mechanism which includes high rigidity, high load, good dynamic performance, and easy to realize the movement of multiple degree of freedom model, to develop a kind of new type hybrid vehicle electro-painting transportation agency with the simple structure, strong carrying capacity, high level of flexibility, and wide range of models.For the mixed type conveying mechanism developed by the research group, while building its computer control system, takes the consideration of the control algorithm based on dynamic model adopted by the mixed type conveying mechanism control system and the high requirement for the data processing and real-time control ability of the control system. Therefore, this study adopts principle computer(personal computer) + slave computer(UMAC multi-axis motion controller) under the computer control system of the mixed type transportation agency with the distributed control method. Among them, the principle computer communicates with the UMAC through the Ethernet to complete system initialization, parameter management, code compilation and real-time monitoring tasks during the organization running status; the slave computer is the UMAC multi-axis motion controller, which is used to complete the real-time tasks including interpolation calculation and multi-axis motion control. The control method makes full use of the ability of the principle computer input and display, and high stability, strong real-time characteristics of the UMAC.For an actual engineering system, the output of the actuator is limited. The actuator output saturation phenomenon occurs while the control output of the system exceeds the upper and lower limits of the actuator. The presence of actuator saturation characteristic will reduce the control performance of the system. Aiming at the problem of actuator saturation characteristic,therefore, this paper designs a kind of actuator saturation compensation system to eliminate the influence of actuator saturation characteristic during controlling system. To design a sliding mode controller of actuator saturation for the mixed type conveying mechanism.Compound type automobile electrophoresis coating in order to achieve the new high performance control of transport agencies, the actuator saturation compensation system is combined with sliding mode control. In this paper, the research has the theoretical value and the practical value in engineering.The main researching contents of this paper and results are as follows:(1) For the new hybrid type conveying mechanism, adopt the distributed structure of "under the PC(personal computer) + a machine(UMAC multi-axis motion controller)" to construct the compound type conveying mechanism control system hardware platform.(2) Based on the hardware platform, design the compound type conveying mechanism control system software.(3) For the brand new mixed type transport agency, the automobile body to be delivered to load, kinematics analysis is carried out on the transmission mechanism to obtain the speed Jacobi matrix. Then, on the basis of kinematics analysis, the Lagrange method is adopted to establish the mixed type of transport organization in Cartesian space dynamic model of mixed type conveying mechanism and further obtain the dynamic model in joint space. Finally, to establish the kinematics model and dynamic model are simulated respectively by using MATLAB software. From the simulation results, the feasibility of the kinematics model and dynamic model which are built is verified.(4) Aiming at the actuator saturation problem caused by the large amount of controller output, design a kind of actuator saturation compensation system to eliminate the influence of actuator saturation characteristic for the control system. Then, the actuator saturation compensation system is combined with sliding mode control, design a kind actuator saturation sliding mode controller with the consideration of actuator saturation for the compound type conveying mechanism. Finally, using the MATLAB software simulation, the simulation results show that the sliding mode controller with considering actuator saturation has good tracking performance and can effectively solve the actuator saturation problem that exists in the practical engineering systems.(5) The experiment is carried out based on the experimental platform of computer control system, and the results show that the proposed sliding mode controller with considering actuator saturation is correct and effective.