基于状态观测器的空间机械臂关节故障诊断

State observer based joint failure diagnosis of space manipulators

为了实时检测空间机械臂关节故障的发生并获得有效的故障信息,提出一种基于状态观测器的关节故障诊断方法。通过结合滑模变结构控制理论设计滑模状态观测器,获得机械臂各运行状态的残差信息,并将其与设定的阈值比较,实现关节故障的检测。进而引入不同的故障模式,构建故障数据库,将实际关节故障所导致的机械臂故障残差信息与故障数据库对比,完成故障发生位置及其故障程度的识别。所提诊断方法考虑了空间机械臂系统内部强耦合特性,能够及时检测故障的发生并获取有效的故障信息。最后以7自由度空间机械臂为对象开展数值仿真研究,验证了所提关节故障诊断方法的有效性。

To detect the joint failure of space manipulators in real time and obtain effective fault information,a fault diagnosis method based on state observers is proposed.Through the design of a sliding mode state observer based on the sliding mode control theory,the residual information of each running status for the manipulator is obtained.A comparison of the residual information and the preset threshold is then conducted to achieve joint failure detection.In addition,different failure modes are introduced to build a failure database with which the residual information of the manipulator caused by the actual joint failure is compared,thereby realizing the location and degree identification of the failure.Taking the strong coupling characteristics of the space manipulator into account,the fault diagnosis method proposed in this paper can detect the joint failure in time and obtain effective fault information.The effectiveness and correctness of the proposed method is verified by numerical simulation of a 7-DOF space manipulator.