然而，[11]仅假设扰动是有界的，通过符号函数消除外界扰动的影响，控制

However, [11] only assumes that the disturbance is bounded. Through the sign function to eliminate the influence of the external disturbance, the controller can make the state enter the designed sliding mode surface, but it will produce a large jitter phenomenon, and the method cannot understand the external Disturbances and unknown functions affect the system, so this paper designs a disturbance observer. On the one hand, it is to accurately estimate the mixed disturbances composed of dead zone input errors, fuzzy estimation errors, and external disturbances. On the other hand, the control effect will also be relative to the traditional The control method has been further improved while reducing the jitter phenomenon. This article can be regarded as a continuation of the literature [11].

However, only assuming that the perturbation is boundary, through the symbol function to eliminate the influence of external disturbance, the controller can make the state into the design of the sliding mode surface, but will produce a larger jitter phenomenon, and the method can not understand the external disturbance and unknown functions on the system, so this paper design perturbation observer, on the one hand, in order to accurately estimate the dead area input error, fuzzy estimation error, external disturbance composed of mixed disturbance, on the other hand, the control effect will be improved relative to the traditional control method and reduce jitter at the same time. This article can be seen as a continuation of the literature.

However, [11] only assumes that the disturbance is bounded. By eliminating the influence of external disturbance by symbolic function, the controller can make the state enter the designed sliding mode surface, but it will produce large jitter. Moreover, this method can not understand the influence of external disturbance and unknown function on the system. Therefore, the disturbance observer is designed in this paper, on the one hand, to accurately estimate the input error from the dead zone On the other hand, compared with the traditional control method, the control effect will be further improved and the jitter phenomenon will be reduced. This paper can be regarded as a continuation of reference [11].