Human Performance in Six Degree of Freedom Input Control

Shumin Zhai, Ph.D.

2.1 Introduction

Figure 2.1 The design space of Experiment 1Figure 2.1 The design space of Experiment 1

As discussed in Chapter 1, there are numerous existing and potential input control techniques for manipulation in 6 DOF. This chapter focuses on two of the many dimensions in 6 DOF input device design: controller resistance and transfer function. There were many reasons for choosing these two dimensions as the independent variables of the inaugural experiment. First, they cause very different user behaviours. Variations along each of these two dimensions change the way that a user performs manipulation tasks. Second, it is unknown whether and how much these behavioural differences alter users' 6 DOF manipulation performance. Third, many other design dimensions, such as desktop versus free-moving, or direct hand projection versus tool-using are related to these two dimensions. Finally, there existed a conceivable interaction between the two dimensions.

To span the entire space shown in Figure 2.1 in one experiment is not practical. This chapter treats only the four extreme cases, representing each corner of the X Y plane shown in Figure 2.1. In a counter clockwise direction around the X Y plane, the four cases are: isotonic position control, isotonic rate control, isometric rate control and isometric position control. The next two sections analyse the differences between these and review the literature on each of the two dimensions in Figure 2.1.