智能控制智能控制智能控制 (14).pdf
Structure of Expert Control SystemsStructures of Expert ControlExpert control consists of knowledge base;inference engine(reasoning machine);control rules;algorithms and so on.Tasks the Expert System Should Perform Tasks the expert system should perform Supervise the operation of the plant(process)and controllerExamine possible failure or fault of the system componentsSelect suitable control algorithm to adapt the variation of the system parametersIndustrial Expert Controller The knowledge base(KB)is a basic component of the expert controller.The key problem for building knowledge base is how to express the acquired knowledge.Industrial Expert ControllerThe set of control rule(SCR)sums up every control pattern and control experience of the controlled process.A forward chaining reasoning method is used to judge the conditions of every rule in the sequence.If the condition is satisfied,then the rule would be carried out;otherwise,the search will be continued.Blackboard Expert Control System Blackboard architecture is a powerful expert system architecture and problem-solving model.Blackboard can deal with large amounts of diverse,erroneous,and incomplete knowledge to solve problems.The Components of the Blackboard Control SystemBlackboard(BB)Control unitKnowledge sources(KSs)The Components of the Blackboard Control SystemBlackboard(BB)The objects that are placed on the BB could be input data,partial results,etc.Each entry on the BB can have an associated certainty factor.Blackboard is used to store knowledge accessible to all the knowledge sources.Interaction among the KSs is carried out via the BB.The Components of the Blackboard Control SystemKnowledge sources(KSs)The knowledge sources in a blackboard system are separated and independent.Knowledge sources are self-selecting modules of domain knowledge.The action part of KS can be a production rule system with forward-backward chaining or a frame-based system with slot-filling procedures attached to some slots.The Components of the Blackboard Control SystemControl unit A control unit is a database with control data objects.A group of control knowledge sources can dynamically construct plans for achieving the systems behavior.The basic problem-solving mechanism in a blackboard system starts with the addition of information to the blackboard by a knowledge source.A Case:Mobile robot The great interest for flexibility of control that a blackboard architecture offers is in the control of an autonomous mobile robot.A blackboard architecture for an expert system for controlling a mobile robot was proposed,and the implementation of this expert control system has been carried out.