Firstly, the discontinuous function is substituted by Terminal attractor function to eliminate chattering. To
solve the problem that it is difficult to choose proper design parameters for higher-order differentiator, the range of design
parameters is relaxed and the stability of higher-order differentiator in different conditions is proved. By analyzing design
parameters and system structure, a design method which is more suitable for engineering application to reduce estimation
error is proposed and the conditions needed are given. Finally, the simulation results show the effectiveness and correctness
of these conclusions.