Characteristic equation and stability determination of sweating manikin

The two parameters(damping ratio ξ and nature surge frequency ω_n) of the system are obtained through the step response curve of sweating manikin.According to the values of ξ and ω_n,the stability of sweating manikin system can be determined.The experimental results show that in the control process of manikin surface skin temperature,when ξ is 0.804,it illustrates that this control system is an underdamping second-order system.The surge process is attenuation.When the nature surge frequency ω_n equals to(0.004 6),the stability of this control process is very good.In the control process of manikin surface wetness,when ξ is 0.643,it illustrates that this control system is also an underdamping second-order system.The surge process is attenuation,too.When the nature surge frequency ω_n equals to(0.002 8),the stability of this control process is also very good.