Normal and structural technical features should be described by describing the structure. When some structures can't be accurately described by the description of specific structures, they can be described by the functions that can be realized by the structures, but only if the technicians in the field can obtain the technical solutions to realize the functions according to the contents defined by the functions without creative labor.
Your example includes control. Let me give you an example of electricity, hoping to help you understand:
A square wave generator for generating a square wave with a duty ratio of 1KHz of 50%.
The above are functional limitations. According to the function description of the square wave sounder, a person skilled in the art can design a specific circuit structure, so this restriction is allowed by the patent law.
However, due to the wide range of functions, that is, there may be multiple specific technical solutions to realize a function, which will affect the creativity of technical solutions. In addition, if there are not enough examples in the specification to support the above-mentioned functional limitations, it will also cause the problem that the claims are not supported by the specification.
The above personal views are for reference only.