| Summary: | 博士 === 中原大學 === 工業工程研究所 === 96 === In this study, the Steward platform was used to produce a vibration environment of 6 degrees of freedom. The workstation and 10 subjects 26~31 years of age were in the vibration environment to operate different pointing devices including a touch screen, a mouse, and a track ball. The subjects were requested to perform the Fitts' law task for identifying the characteristics of movement time, error rate, and end-point variation. The target size, throughput and Fitts' law model were analyzed for each pointing device in this study to find out the pointing devices that were most suitable for operation in the vibration environment.
As the results showed, the throughput of each pointing device decreased with increase of vibration. The Fitts' law model of the mouse was MT=389+123log2D+212log21/W +578av,comfort. The distribution of the end points and the clicking error rate increased with the increase of the vibration. The end points were closer to the target center and distributed more centrally than the touch screen and track ball. The effective target width increased to a limited extent. Though the movement time is longer than the touch screen, the throughput is higher in the vibration environment. The Fitts' law model of the touch screen is Fitts' law model was MT=335+119log2D+275log21/W +427av,comfort+42sinθ. It had a shorter movement time and a better throughput in a static environment. The movement time increased with the increase of the movement angle and vibration. The position of the end points was farthest away from the target center and their distribution increased more significantly than the mouse and trackball. As a result, both the clicking error rate and the effective target width increased to a significant extent and, thus, the throughput was lower than the mouse, indicating that the touch screen was less capable of resisting the vibration environment. The Fitts' law model of the track ball was MT=1031+44D+611[(1/W)-1]-147av,comfort. With increase of the vibration, the clicking error rate decreased to be lower than the clicking error rate of the mouse and the touch screen. Though the distribution of the end points increased with the increase of the vibration, it did not increase as significantly as the mouse and touch screen, resulting in an insignificant increase of the effective target width. It indicates that the track ball was more capable of resisting the vibration environment but had the worse throughput due to long movement time.
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