| Hydraulic excavator with an adverse bucket is a kind of machinery which is used widely. It is very important in basic construction.But because its method of control is traditional which is controled by a skillful operator, this is hard to the operators and some special effects are not exact enough. The automatic controller is needed.The text is to explore a method of control to control the trace of the hydraulic excavator,and it can also be expected to solve the problem.This article deals with problems as following: It deducted the methematic model of the system.It first selected PID controller which is triditional and analysed the time domain and the frequency domain character of the system. It got that the system held its stability and the time domain and the frequency domain character of the system were better than primary system. Then it used BP neural network which is one of the modern intelligent control methods,and the model of the neural network direct negtive control. It did digital simulation to the controll system, and the results were compared with the PID control system. It got that the result was better which was the response time was shorter, the capability of tracking the input changing and the self adapting was stronger. To supply the sufficiency theory guide to the experience, it emulated the the device of excavator using VC++, and compared the trace. From the results, we can get that the effect controlled by BP neural network is satisfied.After the precise theoretical design and caculation have done, the methods of PID control have applicated in the experimental installation, which used PC as the the central processing unit and compiled the control software by using VC. Then the installation was debuged and run. The angle message from the sensor was conversed through the conversion of coordinates, and the termination of the bucket was obtained. After the continuous points were described in the coordinate system, the practical straight-line excavate tracer came.
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