Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close t...Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close to ±60° when driven by SMA triple wires. The fuzzy proportional-integral-derivative （PID）-controlled actuator drive was designed using antagonistic SMA triple wires, and the resistance feedback signal made a closed loop. Experiments showed that, with the driving responding frequency increasing, the overstress became harder to be avoided at the position under the maximum friction force. Furthermore, the hysteresis gap between the heating and cooling paths of the strain-to-resistance curve expanded under this condition. A fuzzy logic control was considered as a solution, and the curves of the wires were then modeled by fitting polynomials so that the measured resistance was used directly to determine the control signal. Accurate control was demonstrated through the step response, and the experimental results showed that under the fuzzy PID-control program, the mean absolute error （MAE） of the rotation angle was about 3.147°. In addition, the investigation of the external interference to the system proved the controllable maximum output.展开更多
自平衡机器人是验证各种控制算法的经典装置,研究传输时滞对其控制系统的影响具有重要意义。基于李雅普诺夫-克拉索夫斯基(Lyapunov-Krasovskii,L-K)泛函方法讨论了自平衡机器人的控制问题。首先,建立了直流电机的线性化模型,并应用拉...自平衡机器人是验证各种控制算法的经典装置,研究传输时滞对其控制系统的影响具有重要意义。基于李雅普诺夫-克拉索夫斯基(Lyapunov-Krasovskii,L-K)泛函方法讨论了自平衡机器人的控制问题。首先,建立了直流电机的线性化模型,并应用拉格朗日方程法建立了自平衡机器人的线性数学模型;然后,进一步考虑传输时滞环节,建立基于多闭环比例积分微分(proportional integral differential,PID)控制器的自平衡机器人控制系统的整体状态空间模型;最后,应用广义自由矩阵积分不等式,建立了低保守性的L-K稳定性判据,在此基础上通过MATLAB中的线性矩阵不等式(linear matrix inequality,LMI)工具箱去求解PID控制增益对时滞稳定裕度的影响。仿真结果表明,所提出的系统稳定性判据不仅有效,而且具有较低的保守性。展开更多
基金co-supported by the National Natural Science Foundation of China (61175104)National Science and Technology Support Program of China (2012BA114B01)
文摘Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close to ±60° when driven by SMA triple wires. The fuzzy proportional-integral-derivative （PID）-controlled actuator drive was designed using antagonistic SMA triple wires, and the resistance feedback signal made a closed loop. Experiments showed that, with the driving responding frequency increasing, the overstress became harder to be avoided at the position under the maximum friction force. Furthermore, the hysteresis gap between the heating and cooling paths of the strain-to-resistance curve expanded under this condition. A fuzzy logic control was considered as a solution, and the curves of the wires were then modeled by fitting polynomials so that the measured resistance was used directly to determine the control signal. Accurate control was demonstrated through the step response, and the experimental results showed that under the fuzzy PID-control program, the mean absolute error （MAE） of the rotation angle was about 3.147°. In addition, the investigation of the external interference to the system proved the controllable maximum output.
文摘自平衡机器人是验证各种控制算法的经典装置,研究传输时滞对其控制系统的影响具有重要意义。基于李雅普诺夫-克拉索夫斯基(Lyapunov-Krasovskii,L-K)泛函方法讨论了自平衡机器人的控制问题。首先,建立了直流电机的线性化模型,并应用拉格朗日方程法建立了自平衡机器人的线性数学模型;然后,进一步考虑传输时滞环节,建立基于多闭环比例积分微分(proportional integral differential,PID)控制器的自平衡机器人控制系统的整体状态空间模型;最后,应用广义自由矩阵积分不等式,建立了低保守性的L-K稳定性判据,在此基础上通过MATLAB中的线性矩阵不等式(linear matrix inequality,LMI)工具箱去求解PID控制增益对时滞稳定裕度的影响。仿真结果表明,所提出的系统稳定性判据不仅有效,而且具有较低的保守性。
