Study On Control Strategy And Fuzzy Integrated Control For The Tractor-implement Combination Simulated System

The dynamics of a tractor-implement combination were complex in the atrocious working environment and fluky work status. A lot of components were not assured. The system had an evident non-linearity problem about large inertial and response lag due to its machine and hydraulic structure. These characteristics were hard to describe by using exact mathematic model. It was difficult to study unit's integrated control by using classic control theory relying on exact mathematic model, or modern control theory relying on status function. About integrated control problems and optimal matching methods on plough implement unit, as an example in this paper, were discussed using fuzzy logical control theory. It gives a practical and referenced method on study auto-control of walking implement combinations.For the convenience of study, a simulation control system of tractor-implement combination was designed, which had the characteristics of reasonable structure, simple and practical. The control system was composed of three parts: master PC monitor system, transmission and throttle control subsystem, engine load simulated control subsystem. Using the system could take many studies on implement units.Engine load simulated control system was consisted of two unattached parts of work resistance simulated control subsystem and electric eddycurrent dynamometer control subsystem. In order to connect them and to let them dynamic response, mathematic models of engine load simulation controller were established, which transfer the work resistance's change to engine load change immediately, to meet the simulation control system.Couplings among parameters of tractor-implement combination bring about difficulties in integration control. On the base of thoroughly studying dynamic characteristic of tractor-implement combination, a control project of three parameters was put forward in the paper. The three parameters were engine load rate, drive wheel slip and work resistance. An integrated control model based on three parameters was established, which reflects colligated dynamic character of the unit.The paper put forward three integrated control strategies adapting full of engine load, i.e. highest production efficiency control strategy, oil consume economic control strategy and give attention to the above control strategy. To aim at different task apply correspondent control strategy. So the simulation control study had practical purpose.Two control circuits were designed in the paper: gear control circuit and throttle control circuit. And corresponding fuzzy control arithmetic was studied to control engine work point. These circuits had the characteristic of quick adjustment and good stabilization, which was fitted to the real need of tractor work.Real monitor software of the master PC was developed by using VC++6.0 and adopting the method of Object-Oriented Programming. The monitor software has two functions of manual and automatic control. The operator can adjust the setting parameters online in order to meet different quality and need of the control.The simulated experiment showed that the control system, control model and control arithmetic designed by author in the paper achieve the expected control purpose. It provided a reference method to study integrated control of tractor-implement combination.