really exist
5.In the positioning servo-system,which generally is configured by the D.C.pulse width modulator (PWM) velocity governing system and position servo-loop,the parameter perturbance of PWM velocity loop really exist by reason of such as the load behavior;power voltage supply;operating setting value, etc.［1,2］，and it cannot be ignored.By using the identification technique to form the mathematical model of the system,authors have confirmed the facts.Therefore,to design the discrete sliding mode controller (DSMC) of the positioning servo-system,the perturbed parameters value bounds of the PWM velocity loop,which is as the controlled plant of position servo-loop,should be accounted.Consequently,the design principle of DSMC for accounting system with parameter perturbance is proposed by the authors.The proposed method can ensure the stability of system with parameter perturbance and the behavior of non-overshoot,fast precise positioning.In order to reveal the effects of the design method,the comparative research work is done by the authors.Also,it has been tested in an industrial experiment,the results proved it is satisfactory.
10.If special circumstances exist under which it is really necessary for state industrial and mining projects to occupy land within the planned reserve zones mentioned in the preceding paragraph, approval should be obtained according to the procedures set by the state for capital construct ion and consultations should be made with the relevant water conservancy administrative department.
