4.4 Results
5.3.1 Experimental Setup
Based on the results from the previous experiment, I determined that the Unity3D gaming engine offers a sophisticated environment compare to the other two. It allowed me to use more gaming features to build the telerobotic interface with MR and HSC concepts applied. Similar to the setup of the previous experiment, I set this system into local and remote areas.
Remote Machine 2 x PTZ Cameras Remote Workspace And Block Targets Mixed Reality Interface Input Devices: Keyboard & Mouse
Human Operator
Figure 5.5: Experimental setup for third experiment
As shown in Figure 5.5, the local area consists of a personal computer connected to a 32‖ monitor Dell with a resolution of 2560 x 1600 pixels as a display. A standard keyboard and mouse were used as the input devices to deliver the user‘s commands through the interface. A telerobotic interface with MR environment and HSC was applied in this local machine.
A computer server was located at the remote area; which delivered information between the user machine and the remote manipulator. A 3-DOF (degree of freedom) modified robot arm served as the remote manipulator. The robot arm was located on a stage with a hole representing a dump-bin in the middle of the workspace. Three blocks were provided on the workspace stage as objects targeted for sinking into the hole. Similar to the previous experiment, the IP cameras (external camera) were installed in static positions at the front and side of the telerobot and facing the workspace stage. However, in this experimental scenario, to apply MR and reduce distraction from multiple camera views, only the front camera was utilised and embedded inside the telerobotic interface. In addition to providing streaming video to the interface, the camera also connected to the server to serve as a tracking sensor and provide updates on the position of the target objects through image analysis.
The interface used for the experiment provides information from both the camera view and the 3D model. The embedded camera provides information regarding what is really happening at the remote location before and after giving commands to the telerobot; it provides any additional information if any is missing from the 3D model view (e.g. different number or
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position of the rocks due to errors of the tracking system). In this experiment, I set the initial view of the virtual camera to that of the external camera and make this the default view for each participant. The participant is expected to be able to perform spatial transformation using this information. The participant can change the view of the virtual camera to see more detail about the remote environment.
Prior to the start of the experiment, all participants were given a brief description of the goals and purpose of the experiment, how to conduct the experiment, and the experimental setting, including information concerning the telerobotic interface and the location of the external camera.
5.3.2 Participants
The experiment was conducted with a total of 24 participants. They were selected by using experiment driven sampling with a snow-ball sampling method. The characteristics of all participants can be seen in the table below:
Table 5.1: Participants characteristics
Characteristics Percentage (%) Gender Male Female 79% 21%
Range of ages Range:
16 – 37 years old
(Mean = 22.75, SD = 5.75 years old)
Background University educated
Computer use
Less than 7 hours/week
Between 7 and 21 hours/week
More than 21 hours/week
13% 26% 61% Computer gaming play
Less than 7 hours/week
Between 7 and 21 hours/week
More than 21 hours/week
50% 25% 25%
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5.3 User Study
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5.3.3 Experimental Design and Procedure
To explore the capabilities of gaming features in implementing HSC and providing continuity with previous experiments, I applied HSC input commands using a ‗click‘ function. This function was combined with a virtual object, described in subsection 5.2.3, to help the operator in planning. I refer to these virtual objects as ―planning information.‖
Based on the model of response movement for multi-command input, described in subsection 2.3.3, I grouped the experiment into: (1) Adaptation model with planning information (Adaptation-info); (2) adaptation model without planning information (Adaptation- non-info); (3) queue model with planning information (Queue-info); and (4) queue model without planning information (Queue-non-info).
For all four, the task was to choose a block and push it into a hole following a path specified by an arrow. The initial robot-arm and block positions were the same for each participant. All participants were asked to select one block by clicking on its model. They were allowed to change their selected block by clicking on another block model which would automatically assign the remaining blocks as obstacles.
The participants were randomly assigned to model-test sequences. Participants were given a 10-15 minutes briefing on the aims of the experiment and the differences between the models. The task scenario was also provided to the participants prior to the experiment. No practice or trial was allowed prior to the experiment.
A maximum time of 180 seconds was allocated to perform the task for each model. During the experiment, the extent to which the user followed the virtual arrow path and whether they sank the block were recorded as the variable outcomes. A successful result was achieved when the participants followed the path assigned and sank a block into the hole during the time allocated. Actual completion times were also recorded when the participant sank the block in the hole before 180 seconds. In addition, the total number of commands given in manipulating the robot arm and virtual camera, and the total usage of stop functions for each model performance were recorded automatically by the system. These variables were noted as user performance indicator in analysing the performance of each model.
After completing the requested task, the participants were also asked to fill in a questionnaire using a seven point Likert-scale and answer open-ended questions. These were used as subjective measurements.