带有时变计算时延的倒立摆视觉实时控制研究

摘要

针对倒立摆视觉实时控制系统中,通过每帧图像处理检测小车位移和摆杆偏角带来的时变图像处理计算时间,直接影响控制系统采样周期和系统性能的问题,不同于目前不考虑图像处理计算时间或将其视为定时滞进行倒立摆视觉实时控制的研究方法,本文首先构建了倒立摆视觉伺服控制实验平台,考虑倒立摆的小车与摆杆特征,提出了小车位移和摆杆偏角的实时计算方法;然后统计分析了图像处理计算时间的特性并设计了视觉传感事件触发采样策略,进一步刻画了时变时延与计算时间的直接关系,进而建立了带有时变计算时延的倒立摆视觉控制系统闭环模型,证明了系统稳定性并建立了反映图像处理计算时间与系统稳定性之间的关系.最后,仿真和实时控制实验验证了所提方法的可行性和有效性.%In inverted pendulum visual real-time control system, the sampling period and performance of control system are directly affected by the time-varying image processing computational time from measuring cart position and pendulum angular from each image. Unlike the existing methods on inverted pendulum visual servoing control system without considering image processing computational time or with constant image processing computational time, an experimental inverted pendulum visual servoing control platform is constructed firstly. Considering the characters of the pendulum and the cart, a real-time calculation method for cart position and pendulum angular are then proposed, and the event-triggered sampling mechanism of visual sensor is designed according to the statistical character of image processing computational time. Furthermore, image processing computational time is converted to time-varying delay, and a closed loop control system model of inverted pendulum system with time-varying delay is established. The system stability is proved, while the system stability condition reflects the relationship between time-varying computational delay and system performance. Finally, simulation and experimental results confirm the feasibility and effectiveness of the proposed method.