To introduce this special issue of shared and cooperative control, we will look into history of tools in cooperation between humans and aim to unify the plethora of related concepts and definitions that have been proposed in recent years, such as shared control, human–machine cooperation and cooperative guidance and control. Concretely, we provide definitions to relate these concepts and sketch a unifying framework of shared and cooperative control that sees the different concepts as different perspectives or foci on a common design space of shared intentionality, control and cooperation between humans and machines. One working hypothesis which the article explores is that shared control can be understood as cooperation at the control layer, while human–machine cooperation can include shared control, but can also extend towards cooperation at higher layers, e.g., of guidance and navigation, of maneuvers and goals. The relationship between shared control and human–machine cooperation is compared to the relationship between the sharp, pointy tip and the (blunt) shaft of a spear. Shared control is where cooperation comes sharply into effect at the control layer, but to be truly effective it should be supported by cooperation on all layers beyond the operational layer, e.g., on the tactical and strategic layer. A fourth layer addresses the meta-communication about the cooperation and supports the other three layers in a traversal way.@en

As an introduction to the session of shared and cooperative control, this article will briefly look into the history, start with definitions and sketch a common framework of shared and cooperative control that sees the two phrases not as different concepts, but as different perspectives or foci on a common design space of shared intentionality, control and cooperation between humans and machines. One working hypothesis which the session will explore is that shared control can be understood as cooperation at the control level, while human machine cooperation can include shared control, but can also extend towards cooperation at higher levels, e.g. of guidance and navigation, of maneuvers and goals. We propose to view the relationship between shared control and human-machine cooperation as being similar to the relationship between the sharp, pointy tip and the (blunt) shaft of a spear. Shared control is where cooperation comes sharply into effect at the control level, but to be truly effective it should be supported by cooperation on all levels of interaction beyond the control level, e.g. on the guidance and navigation level.@en

Shared Control, where the machine and the human share tasks and control the situation together, and its extension cooperative automation are promising approaches to overcome automation-induced problems, such as lack of situation awareness and degradation of skill. However, the design of Shared Controllers and/or cooperative human-machine systems should be done in a very careful manner. One of the major issues is conflicts between the human and the machine: how to detect these conflicts, and how to resolve them, if necessary? A complicating factor is that when the human is right, conflicts are undesirable (resulting in nuisance, degraded performance, etc), but when the machine is right, conflicts are desirable (warning the operator, or proper assistance or overruling). Research has pointed out several types and causes of conflicts, but offers no coherent framework for design and evaluation guidelines. In this paper, we propose such a theoretical framework in order to structure and relate different types of conflicts. The framework is inspired by a hierarchical task analysis, and identifies five possible sources of conflicts: intent, information gathering, information processing, decision-making and action implementation. Examples of conflicts in several application domains such as automobile, telerobotics, and surgery are discussed to illustrate the applicability of this framework.@en