The Front Wheel Of The Plane To Manipulate Digital Controller

Nose wheel steering system (NWSS) provides directional control of the aircraft during ground operation in two modes. These modes are nose wheel steering and shimmy dampening. NWSS is important to the safety of aircraft taking off and landing. In this paper, the digital fly-by-wire NWSS is proposed based on the mechanic-hydraulic NWSS. The digital dual-redundant controller of NWSS is put forward based on TMS320F2812.On the base of researching the transfer function model and analyzing the control algorithm, the PID controller and fuzzy controller are set up. The simulation analyses of PID control and fuzzy control have been finished by using Matlab tool. Compared with PID control, the performance of fuzzy control is better.Hardware is set up and the source code of software program is compiled by C language. The controller using similar redundancy has two redundant channels. The hardware circuits and software programs are designed by using modular design of function. The hardware circuits are composed of the minimum system of DSP, power supply, sampling circuit, D/A converter circuit, driver circuit, dual-channel communication circuit, serial communication circuit and other components. The servo driver circuit and sampling circuit are important to the controller. The analysis of servo driver circuit is completed by simulation. The function of software is introduced with steering control, redundancy management, saving data, serial communications and so on. The detailed strategy of redundancy management is presented and completed. The protocol of serial communication is set up.Reliability model of digital dual-redundant controller is developed based on the markov process. It is proved by the simulation results that the dual redundant controller reduces the system failure rate and improves the system reliability.The design, production and experiments of the controller are finished completely. The results prove that the hardware of the digital controller is feasible, the control algorithm is correct and efficiency, the operation of the controller is simple and flexible. The performance of NWSS is improved.