Fault tolerant mechatronic actuator systems with realisation of an electrical duplex power steering

自最初的要求以来，汽车行业对安全关键系统的双工执行器的普遍兴趣有所增加。初始请求的任务和我们的研究结果对于容错执行器系统是非常重要的。未澄清的任务和新提出的问题说明如下。所开发的执行器模型的精度有待进一步提高。因此，电机模型应通过半物理建模进行扩展。采用这种方法可以更好地处理滞后等非线性效应。这对于故障诊断尤其重要。残差是模型结构分析的结果，必须在现有的测试台上进行验证。根据验证结果，进行扩展故障建模。提出了一种执行机构故障处理方法。通过半物理建模来提高耦合控制的鲁棒性。将耦合控制扩展为增益调度控制器。特别是在一个致动器完全击穿的情况下，选择正确的开关策略非常重要。硬开关或软开关的影响很大程度上取决于具体情况。现有的双eps试验台应增加致动器以产生转向力反应。这使得主动负载模拟和试验台可以在闭环中运行。可以研究驾驶情景切换策略。目的是在实时目标上集成车辆仿真。为了使所选控制器在故障时具有良好的自适应性，对内模控制进行了分析。由于控制器具有内部模型，可以通过参数自适应对控制结构进行自适应。速度和定位控制回路应实现与IMC结构。此外，还应在试验台上研究几种适应IMC的参数估计技术。传感器故障很容易导致错误的执行值。为了尽量减少故障电流和转子位置传感器的影响，应产生虚拟测量信号。最后，对故障管理系统中各种方法的集成进行分析，并利用各种方法的协同作用，以减少计算需求。

The general interest on duplex actuators for safety critical systems is for instance in the automotive sector increased since initial request. The tasks of the initial request and the results of our research are basically important for fault-tolerant actuator systems. The not clarified tasks and the new developed questions are described below.The accuracy of the developed actuator models should be further increased. Therefore the motor model should be extended by a semi-physical modeling. With this approach nonlinear effects like hysteresis could be handled better. This is particularly important for fault diagnosis.The residuals, which are the result of a structure analysis of the models, must be validated at the existing test benches. Depending on the validation results, an extended fault modeling will be done.An approach for handling actuator faults was developed. The robustness of the used coupling control should be improved by a semi-physical modeling. The coupling control will be extended to a gain-scheduling controller.Especially at a total breakdown of one actuator, the choice of the right switching strategy is important. The impact of a hard or soft switching highly depends on the situation. The existing duplex-EPS test bench should be extended by actuators for generating steering force reactions. This allows an active load simulation and the test bench can operate in closed loop. Driving situational switching strategies can be researched. An integration of a vehicle simulation at the real-time target is intended.In order to get a good adaptability of the chosen controller at a fault the internal model control (IMC) was analyzed. Because of the internal model in the controller the control structure can be adapted easily by parameter adaption. A speed and a positioning control loop should be implemented with the IMC structure. Additionally several parameter estimation techniques for the adaption of the IMC should be investigated at the test bench.Faults of sensors can be easily followed by wrong actuating values. To minimize the impact of faulty current and rotor position sensors virtual measurement signals should be generated.Finally, the integration of all methods in a fault management system should be analyzed and synergies of the methods should be used in order to reduce the computing demand.