Copper nitride （Cu3N） thin films were successfully deposited on glass substrates by reactive radio frequency magnetron sputtering.The effects of sputtering parameters on the structure and properties of the films wer...Copper nitride （Cu3N） thin films were successfully deposited on glass substrates by reactive radio frequency magnetron sputtering.The effects of sputtering parameters on the structure and properties of the films were studied.The experimental results show that with increasing of RF power and nitrogen partial pressure,the preferential crystalline orientation of Cu3N film is changed from （111） to （100）.With increasing of substrate temperature from 70 ℃ to 200 ℃,the film phase is changed from Cu3N phase to Cu.With increasing sputtering power from 80 W to 120 W,the optical energy decreases from 1.85 eV to 1.41 eV while the electrical resistivity increases from 1.45 ×102 Ω·cm to 2.99×103 Ω·cm,respectively.展开更多
The advantages of permanent magnet linear synchronous motors （PMLSM） include high speed and good motion precision compared with rotary motors. However, PMLSM are sensitive to uncertainties such as the parameter pert...The advantages of permanent magnet linear synchronous motors （PMLSM） include high speed and good motion precision compared with rotary motors. However, PMLSM are sensitive to uncertainties such as the parameter perturbations and end effect etc. A new nonlinear robust scheme of PMLSM is proposed to overcome this trouble. First, a quasi-linearized and deeoupled model with uncertainties is derived from the mathematical model of PMLSM by using the conception of feedback linearization. Then a fixed-boundary-layer sliding mode controller using the m sat function is designed to guarantee the robustness. Design of a force observer is given to estimate the load force unknown in the new model. Finally, the validity of the proposed strategy compared with the conventional PID control scheme is proved by the DSpobased experimental results.展开更多
The problem of adaptive stabilization of a class of multi-input nonlinear systems with unknown parameters both in the state vector-field and the input vector-field has been considered. By employing the control Lyapuno...The problem of adaptive stabilization of a class of multi-input nonlinear systems with unknown parameters both in the state vector-field and the input vector-field has been considered. By employing the control Lyapunov function method, a direct adaptive controller is designed to complete the global adaptive stability of the uncertain system. At the same time, the controller is also verified to possess the optimality. Example and simulations are provided to illustrate the effectiveness of the proposed method.展开更多
Integrator forwarding is a recursive nonlinear design technique for the stabilization of feed-forward systems. However, this method still has some limitation. An improved design method is proposed to extend the field ...Integrator forwarding is a recursive nonlinear design technique for the stabilization of feed-forward systems. However, this method still has some limitation. An improved design method is proposed to extend the field of application of this technique. This method is used to design a stabilizer for the inertia wheel pendulum system. Moreover, it is shown that the control Lyapunov function which is obtained from this method can also be used to design a globally asymptotically stabilizing controller with optimality.展开更多
基金Funded by the National Natural Science Foundation of China (No.60571010)
文摘Copper nitride （Cu3N） thin films were successfully deposited on glass substrates by reactive radio frequency magnetron sputtering.The effects of sputtering parameters on the structure and properties of the films were studied.The experimental results show that with increasing of RF power and nitrogen partial pressure,the preferential crystalline orientation of Cu3N film is changed from （111） to （100）.With increasing of substrate temperature from 70 ℃ to 200 ℃,the film phase is changed from Cu3N phase to Cu.With increasing sputtering power from 80 W to 120 W,the optical energy decreases from 1.85 eV to 1.41 eV while the electrical resistivity increases from 1.45 ×102 Ω·cm to 2.99×103 Ω·cm,respectively.
文摘The advantages of permanent magnet linear synchronous motors （PMLSM） include high speed and good motion precision compared with rotary motors. However, PMLSM are sensitive to uncertainties such as the parameter perturbations and end effect etc. A new nonlinear robust scheme of PMLSM is proposed to overcome this trouble. First, a quasi-linearized and deeoupled model with uncertainties is derived from the mathematical model of PMLSM by using the conception of feedback linearization. Then a fixed-boundary-layer sliding mode controller using the m sat function is designed to guarantee the robustness. Design of a force observer is given to estimate the load force unknown in the new model. Finally, the validity of the proposed strategy compared with the conventional PID control scheme is proved by the DSpobased experimental results.
文摘The problem of adaptive stabilization of a class of multi-input nonlinear systems with unknown parameters both in the state vector-field and the input vector-field has been considered. By employing the control Lyapunov function method, a direct adaptive controller is designed to complete the global adaptive stability of the uncertain system. At the same time, the controller is also verified to possess the optimality. Example and simulations are provided to illustrate the effectiveness of the proposed method.
文摘Integrator forwarding is a recursive nonlinear design technique for the stabilization of feed-forward systems. However, this method still has some limitation. An improved design method is proposed to extend the field of application of this technique. This method is used to design a stabilizer for the inertia wheel pendulum system. Moreover, it is shown that the control Lyapunov function which is obtained from this method can also be used to design a globally asymptotically stabilizing controller with optimality.
