| Automation of engineering machine are main approaches to enhance productivity and lower manpower cost, and they are inevitable trend of modern industrial technology development as well. In warehouses with stocks stacked disorderly, or workplaces with high radiation or high pollution, like nuclear waste transportation or garbage disposal, It’s especially urgent demand to realize unmanned automotive driving of overhead crane. The target of this dissertation is to realize unmanned travelling of intelligent bridge crane. To achieve this goal, path planning algorithm, automotive control system and motor frequency control are studied on, the integrated control system with human machine interface (HMI), sensors, controller and actuator are designed.Firstly, by researching on the application of path planning technology in other fields like mobile robots, the concept of dividing the environment information by grid is proposed, and ant colony algorithm is adopted in the obstacle avoidance operation. Shortest path length is set as the objective function, and the optimal trajectory is generated in the rasterized virtual environment. In the MATLAB simulation of the discussed method, run the program with results correctly displayed, meanwhile, the environment and trajectory information which can be input into the controller is generated. Thus, the validity of the intelligent path planning of bridge crane in the complex working environment can be confirmed.Based on the path planning method designed, an automotive control program is developed on the CoDeSys PLC Design platform. Environment and trajectory information input from upper computer, control signals and parameters input by the operator from the HMI are integrated in the PLC and handled by different function units programmed in CoDeSys. Through calculation and transformation, the control signals are generated and input into the actuators to control the travelling mechanism of the crane. Moreover, by means of CoDeSys visualization programming function, a human-machine control interface is designed, with this interface, the running condition of the program can be observed and testified on PC end, without relying on PLC special hardware.Lastly, researches on variable frequency speed control system of the bridge crane are conducted. By studying the structure and working principle of three-phase asynchronous motor, and considering the characteristics of bridge cranes, vector frequency regulating technology is adopted in motor speed control. The model of the speed control system is built in MATLAB/Simulink environment, combining with practical engineering cases, simulation is conducted to obtain accurate control effect. The result of the simulation and calculation proves the excellent speed control performance of the system, and also confirms the feasibility and reliability of the autonomous control system designed. |
