Cooperative robots in the workspace have an effect on safety that is not yet fully understood. This work collates pre-existing knowledge on human, technological and organizational factors for human-robot interaction and develops a system dynamics model that captures the complex interactions. Expert consultation in the form of a Delphi study is used to derive a tractable model from pre-existing puzzle pieces. A final model is presented, which contains 10 nodes and 20 relationships containing the three key outcome factors of human-robot interaction, viz. Safety, Efficiency and Sustainability. By combining these factors into a single tractable framework, this model bridges the gap between individual efforts from previous works in the field of robotics.