A fault tolerant control architecture for automated highway systems

A hierarchical controller for dealing with faults and adverse environmental conditions on an automated highway system (AHS) is proposed. The controlle r extends a previous control hierarchy designed to work under normal condit ions of operation. The faults are classified according to the capabilities remaining on the vehicle or roadside after the fault has occurred. Informat ion about these capabilities is used by supervisors in each of the layers o f the hierarchy to select appropriate fault handling strategies. We outline the strategies needed by the supervisors and give examples of their detail ed operation. In a companion paper details of communication protocols imple menting some of these strategies are presented.