A new method used for developing Flexible Task-oriented robot Controls (FTC) using the System Entity Structure (SES) is introduced. Task-oriented robot controls are based on the composition of atomic tasks aimed at achieving a previously specified goal. Flexible task-oriented controls differ in that the composition of atomic tasks is not fixedly predefined but is composed during the operation of the control based on actual process states and with respect to constraints in the sequence of tasks. The System Entity Structure is an ontology, which can be used for hierarchically representing system compositions. For cooperating robots the paper shows how to generate and execute FTCs specified by an SES and an associated model base (MB).