**1. Introduction**

In the past, robots were deployed primarily in industrial scenarios where tasks were repetitive and in a fixed sequence under a structured and well-constrained condition. Robots were programmed and debugged 'off-line', before their programs were ported to the shop floor. The tasks may be expected to be repeated many hundreds of thousands, or even millions of times, 24 hours a day, and continuously for a number of years. A typical example of such a scenario would be in the manufacturing of automobiles. In this 'high volume and low-mix' manufacturing application, the robot actions are explicitly defined and programmed for the robot to execute. The cost and time spent to program and commission each robot would be negligible considering the number of automobiles produced and the relatively long product cycles.

In 'low volume and high-mix' applications, the use of robots may be unattractive due to the relative complexity of robot programming and the related setup costs. As we expand on the scope of robotic applications, a different mode of interaction is evolving. Recently, more robots are deployed in semi-structured manufacturing environment [1] or in domestic environment like in homes [2]. Industrial robots are becoming more collaborative in their interactions with humans and are designed to work with humans in the same environment, without the provision of safety enclosures. In a home setting, it is best that the robot takes on the role of a compliant friend who is able and willing to do our bidding. Tasks required of the robot in such an environment are expected to be different and non-repetitive, at least within a time scale of hours or minutes.

Hence, it is important that the task of programming and interaction between human and robot become more natural and intuitive, evolving to an interaction that is typically associated to that between human. The different operating scenarios require new paradigms in the imple‐ mentation of a Human-Robot Interface (HRI) such that data are clearly presented and easily accessible to all relevant parties. Industrial robots typically present their data on a computer display and often use a keyboard, mouse, or touch pendants as its input device. This setup is not favourable because it causes the human operator to have a divided attention between following the task procedure, visually, and simultaneously monitoring the important param‐ eters on the computer display [3]. Furthermore, in an industrial setting, the need for protective wear would make the usage of the mouse and keyboard or touch pendants untenable.

In this chapter, we propose a framework that uses laser graphics to develop an augmented reality application for HRI. This envisages the evolution of HRI to be more natural with the robot providing a greater contribution in formulating the desired outcome. This invariably moves the robot and human towards a relationship exhibiting greater interaction in terms of frequency and quantity of information exchanged during their interactions. In an environment shared between humans and robots, the human needs to be able to recognise the intention of robots and vice versa. This is to avoid the possibility of conflicts and accidents.

For human and robot to interact meaningfully, through mutual understanding, a mechanism for dialog between robots and humans must exist [4, 5]. The human should be able to define and refine his needs. In addition, the robot is required to deliberate, formulate solutions and present appropriate options, in a form suitable for human understanding. On the other hand, a robot should be able to understand its human partner through common conversational gestures frequently used by humans [6, 7], such as by pointing and gazing. There must also be a common frame of spatial referencing [8, 9] to avoid ambiguities.

**1. Introduction**

166 Recent Advances in Robotic Systems

cycles.

hours or minutes.

In the past, robots were deployed primarily in industrial scenarios where tasks were repetitive and in a fixed sequence under a structured and well-constrained condition. Robots were programmed and debugged 'off-line', before their programs were ported to the shop floor. The tasks may be expected to be repeated many hundreds of thousands, or even millions of times, 24 hours a day, and continuously for a number of years. A typical example of such a scenario would be in the manufacturing of automobiles. In this 'high volume and low-mix' manufacturing application, the robot actions are explicitly defined and programmed for the robot to execute. The cost and time spent to program and commission each robot would be negligible considering the number of automobiles produced and the relatively long product

In 'low volume and high-mix' applications, the use of robots may be unattractive due to the relative complexity of robot programming and the related setup costs. As we expand on the scope of robotic applications, a different mode of interaction is evolving. Recently, more robots are deployed in semi-structured manufacturing environment [1] or in domestic environment like in homes [2]. Industrial robots are becoming more collaborative in their interactions with humans and are designed to work with humans in the same environment, without the provision of safety enclosures. In a home setting, it is best that the robot takes on the role of a compliant friend who is able and willing to do our bidding. Tasks required of the robot in such an environment are expected to be different and non-repetitive, at least within a time scale of

Hence, it is important that the task of programming and interaction between human and robot become more natural and intuitive, evolving to an interaction that is typically associated to that between human. The different operating scenarios require new paradigms in the imple‐ mentation of a Human-Robot Interface (HRI) such that data are clearly presented and easily accessible to all relevant parties. Industrial robots typically present their data on a computer display and often use a keyboard, mouse, or touch pendants as its input device. This setup is not favourable because it causes the human operator to have a divided attention between following the task procedure, visually, and simultaneously monitoring the important param‐ eters on the computer display [3]. Furthermore, in an industrial setting, the need for protective wear would make the usage of the mouse and keyboard or touch pendants untenable.

In this chapter, we propose a framework that uses laser graphics to develop an augmented reality application for HRI. This envisages the evolution of HRI to be more natural with the robot providing a greater contribution in formulating the desired outcome. This invariably moves the robot and human towards a relationship exhibiting greater interaction in terms of frequency and quantity of information exchanged during their interactions. In an environment shared between humans and robots, the human needs to be able to recognise the intention of

For human and robot to interact meaningfully, through mutual understanding, a mechanism for dialog between robots and humans must exist [4, 5]. The human should be able to define

robots and vice versa. This is to avoid the possibility of conflicts and accidents.

Augmented reality (AR) technologies [10] are used in our proposed framework to help the human and robot to define their communication and intentions [11]. Two types of AR technologies – the 'see-through' AR [12, 13] and spatial AR [14, 15] – are applied to enable the human to manipulate the robot in a way that the robot can understand. Similarly, these AR technologies help the robot to convey information so that the human has a better understand‐ ing of what the robot is doing and in its intentions. In research efforts involving the program‐ ming and controlling of mobile robots, there are some that make use of 'see through' AR technologies [11, 16], and others that utilize the spatial AR technologies [8, 17].

In the Mercedes-Benz autonomous concept car programme, laser generated graphics was proposed to indicate when it was safe for a human to cross its path by projecting a moving 'pedestrian crossing'. In this application, the advantages of laser in being able to project images in a natural environment were exploited effectively. In addition, the need for a mobile robot, or vehicle, to communicate its intention to humans was also elaborated.

The desire for a more natural and intuitive interface for human-robot interaction was studied by a number of researchers including [18]. These incorporated laser pointing to assist in defining targets and projected imagery to enhance interaction. In addition, others explored human mimicking interactions [19], while others focused on projectors devices [20].

The design of HRI had previously focused only on the interaction between the robot and the human that is controlling the robot. This is a natural omission, as humans and robots had previous been kept separate as a feature of design. As humans and robots intrude into the other's space, the needs of both humans and robots outside the intended interaction need to be considered. In the sharing of resources, it is important that all parties are aware of the other's intentions. This chapter identifies the need and describes the use of laser-based line graphics in the provision of such a function.
