The hierarchical control level of the controller can vary depending on the specific application scenario and system complexity.
Generally speaking, hierarchical control is to divide the control system into multiple levels, each of which assumes different control tasks and responsibilities to achieve more efficient system management and control.
There is no fixed answer as to how many levels of hierarchical control a controller has, as it depends on the design requirements and goals of the system.
However, in some common control systems, hierarchical control is usually divided into several key levels, such as:
1. Decision layer (or organizational level): This layer is responsible for high-level functions such as reasoning, planning, decision-making, and long-term memory of the entire system. It analyzes and processes various input information (such as sensor data, user instructions, etc.) and makes corresponding decisions to guide the operation of the system.
2. Coordination layer (or middle layer): This layer, as an interface between the decision layer and the execution layer, is responsible for decomposing the instructions of the decision layer into subtasks that can be executed by the execution layer, and coordinating the execution order and priority between the subtasks. At the same time, it also collects information fed back by the execution layer and passes it upward to the decision layer.
3. Execution layer (or bottom layer): This layer consists of multiple specific hardware controllers, which are responsible for executing specific control actions according to the instructions of the coordination layer. It directly controls the physical devices of the system (such as motors, valves, etc.) to achieve the expected functions of the system.
It should be noted that the above three levels are only a common division of hierarchical control, and not all control systems must strictly follow this division.
In practical applications, the hierarchical control level of the controller may be adjusted and changed according to specific needs.
In addition, some more complex control systems may adopt more hierarchical control structures to achieve more refined control and management. For example, in microgrid hierarchical control, the control system may be divided into multiple levels such as primary control, secondary control and tertiary control, and each level is responsible for different control tasks and goals.
In summary, there is no fixed answer for the hierarchical control level of the controller, but it is determined according to the specific application scenario and system requirements. When designing a control system, it is necessary to select a suitable hierarchical control structure according to the actual situation to achieve efficient, reliable and stable system control.