摘要
SMA电阻与温度存在严重的非线性,导致平面弯曲型ESMAA位置控制精度较低。采用两片应变片互补对称的配置方式设计了曲率传感器;结合电机形变分析模型对具体操作进行了规划,形成可达空间上的系列操作点,计算弯曲曲率,进而得到加热电流脉宽;采用B样条算法,完成了电机的路径规划,形成电机的连续运行路径。在分析比较P+、PI+控制算法基础上,充分考虑电机的非线性因素,选取了分段多模式PI控制策略,实现电机的精密位置控制。阶跃实验表明,ε=2m-1,KP=0.05,KI=0.006,Umax=0.8,T=15.4ms,目标曲率18m-1时,上升时间约0.55s,超调量小于2.0%,稳态误差小于0.5m-1,满足控制精度要求。
The nonlinearity between SMA wire＇s resistance and temperature makes displacement control of planar bending ESMAAs inaccurate. To overcome the disadvantage, the novel curvature sensor was developed making use of two gauges which were arranged in differential pairs. The operation plan was completed in cooperation with analytical model for shape change. A series of operation points were determined, ESMAAs＇ curvature was calculated and heating current＇s duty ratio was gained. The track plan was carried out according to B spline interpolated arithmetic and the ESMAAs＇ continuous track was formed. On the basis of comparison between P^＋ and PI^＋ controller, the subsection multi-modes strategy was adopted to realize precise displacement control of ESMAAs. From the experimental results, when the critical error, proportional coefficient, integrating coefficient, maximum duty ratio, sampling time and target curvature are 2m^-1, 0.05, 0.006, 0.8, 15.4ms and 18m^-1 respectively, the rise time is 0.55s, the oveshoot is less than 2.0% and steady error is less than 0.5m^-1, which indicates that the precision of the control system meets practical demand.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2007年第9期83-86,共4页
Proceedings of the CSEE
基金
国家自然科学基金项目(50507007)~~
关键词
内嵌式形状记忆合金电机
平面弯曲
曲率
应变
片
位置控制
embedded shape memory alloy actuator
planar bending
curvature
gauge
displacement control
