Figure 6
The twelve panels are arranged in three rows and four columns, grouped into four conditions labeled “(a)”, “(b)”, “(c)”, and “(d)” at the bottom, each containing three line graphs for “Axis X”, “Axis Y”, and “Axis Z”. In all panels, the horizontal axis is labeled “Time step” and ranges approximately from 0 to 600 in (a), (b), and (d) in increments of 100 units and from 0 to 1000 in (c) in increments of 200 units. The vertical axis is labeled “Acceleration (meters per second squared)”. In condition “(a)”, the legend on each plot is labeled “Normal-Axis X”, “Normal-Axis Y”, and “Normal-Axis Z”. The vertical axis ranges from negative 7.5 to 5.0 in increments of 2.5 in the top plot, from negative 4 to 2 in increments of 2 in the middle plot, and from negative 5.0 to 7.5 in increments of 2.5 in the bottom plot. The signals across all three axes show moderate fluctuations around zero with occasional spikes, including a noticeable peak around time step 200 and another cluster of activity near 500 to 600, with brief sharp dips and rises indicating transient motion. In condition “(b)”, the legend on each plot is labeled “Slowdown-Axis X”, “Slowdown-Axis Y”, and “Slowdown-Axis Z”. The vertical axis ranges from negative 10.0 to 5.0 in increments of 2.5 in the top plot, from negative 2 to 6 in increments of 2 in the middle plot, and from negative 10 to 5 in increments of 5 in the bottom plot. The signals display stronger variability compared to normal, with more frequent spikes and wider amplitude changes, including pronounced peaks around time steps 100 to 200 and again near 500 to 600, along with intermittent quieter intervals. In condition “(c)”, the legend on each plot is labeled “Jamming-Axis X”, “Jamming-Axis Y”, and “Jamming-Axis Z”. The vertical axis ranges from negative 2 to 4 in increments of 2 in the top plot, from negative 10 to 5 in increments of 5 in the middle plot, and from negative 4 to 6 in increments of 2 in the bottom plot. The signals show irregular and abrupt bursts with larger amplitude deviations, including sharp spikes and sudden drops, particularly strong negative excursions in the middle plot and clustered oscillations around time steps near 600 to 800, indicating unstable behavior. In condition “(d)”, the legend on each plot is labeled “Abnormal Door Closing-Axis X”, “Abnormal Door Closing-Axis Y”, and “Abnormal Door Closing-Axis Z”. The vertical axis ranges from negative 5 to 7.5 in increments of 2.5 in the top plot, from negative 2 to 6 in increments of 2 in the middle plot, and from negative 5 to 7.5 in increments of 2.5 in the bottom plot. The signals exhibit strong early fluctuations with distinct peaks around time steps 100 to 200, followed by relatively stable segments and later renewed activity near 500, with noticeable spikes and uneven oscillations across all three axes. Note: All numerical data values are approximated.Three-dimensional vibration signals under different states. (a) Normal. (b) Slowdown. (c) Jamming. (d) Abnormal door closing. Source(s): Figure created by authors