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Summary of Data Collection
For period of
27 May 2011 to 25 August 2011
Daniel Leow ([email protected])
ContentsIntroduction and scope
Data collection setup
Data summary by bus typeAnalysis and findings
Data summary by axesAnalysis and findings
Conclusion
Daniel Leow ([email protected])
Introduction and scope• Data captured in this stage of the research is to
profile the bus motion for each bus type. The profiling of the motion is to determined whether there are differences in bus motion among the three types of the buses.
• Data captured are;
X axis – Lateral motion where negative indicate left motion; positive indicate right motion.
Y axis – Longitudinal motion where negative indicate braking/deceleration; positive indicate acceleration.
Z axis – Vertical motion where negative indicate down motion; positive indicate up motion.
Daniel Leow ([email protected])
Introduction and scope• The three types of buses in Malaysia
Single Deck Low Floor(Metropolitan bus)
Single Deck High Floor(Express bus)
Double Deck (Express bus)
Daniel Leow ([email protected])
Introduction and scopeData captured are;
X axis – Lateral motion where negative indicate left motion; positive indicate right motion.
Y axis – Longitudinal motion where negative indicate braking/deceleration; positive indicate acceleration.
Z axis – Vertical motion where negative indicate down motion; positive indicate up motion.
Daniel Leow ([email protected])
Data Collection SetupBasic hardware and software setup
USB GPS receiver (SiRF Star III)
Macbook Laptop with built-inaccelerometer
Figure 1: Basic Setup
Daniel Leow ([email protected])
Data Collection Setup (cont.)
Position: Equipment mainly placed on a flat surface in the bus to ensure that the accelerometer sensors are directly in contact with the bus.
Figure 2: Equipment in the bus
Figure 3: Equipment in the bus
Daniel Leow ([email protected])
Data Collection Setup (cont.)
Calibration: accelerometer is calibrated to zero point of the raw output values from the sensors
Figure 4: SeisMaCalibrate
Daniel Leow ([email protected])
Data Collection Setup (cont.)
Data: Captured using SeisMac, raw data stored in CSV file format.
Figure 5: SeisMac
Daniel Leow ([email protected])
Data AnalysisDouble Deck
As shown in Graph 1, the lateral force is significantly relative to longitudinal force. As you can see the low and the high spikes are very much at the same frequency.
In Graph 2, the vertical force are relative to the velocity of the vehicle. As you can see that there are higher spikes when the vehicle speed are higher
Daniel Leow ([email protected])
Data Summary Single Deck Low Floor – Graph 3
(lateral and longitudinal)
Daniel Leow ([email protected])
Data Summary Single Deck Low Floor – Graph 4
(vertical and velocity)
Daniel Leow ([email protected])
Data AnalysisSingle Deck Low Floor
As shown in Graph 3, the lateral force is not significantly relative to longitudinal force. The spikes in the longitudinal forces are fairly consistent mainly because there are frequent stops.
In Graph 4, the vertical force are relative to the velocity of the vehicle. As you can see that there are higher spikes when the vehicle speed are higher.
Daniel Leow ([email protected])
Data Summary Single Deck High Floor – Graph 5
(lateral and longitudinal)
Daniel Leow ([email protected])
Data Summary Single Deck High Floor – Graph 6
(vertical and velocity)
Daniel Leow ([email protected])
Data AnalysisSingle Deck High Floor
As shown in Graph 5, the lateral force is significantly relative to longitudinal force. The spikes in the longitudinal forces are fairly consistent mainly because there are frequent stops.
In Graph 6, the vertical force are relative to the velocity of the vehicle.
Daniel Leow ([email protected])
Data AnalysisLateral Force (X axis)
There are higher lateral force for Single Deck Low Floor bus compared to the other two types of the buses.
This would have been expected because the buses taking many turns in the metropolitan roads compared to the express bus usually travels on straight road.
Followed by the Single Deck High Floor bus and the Double Deck bus has the least lateral force motion.
Daniel Leow ([email protected])
Data AnalysisLongitudinal Force (Y
axis)There are higher longitudinal force for Single
Deck Low Floor bus compared to the other two types of the buses.
This would have been expected because the buses have to take frequent stops in the metropolitan roads compared to the express bus usually stops once or twice in the entire journey.
Followed by the Single Deck High Floor bus and the Double Deck bus has the least lateral force motion.
Daniel Leow ([email protected])
Data AnalysisLongitudinal Force (Y
axis)Double Deck and Single Deck Low Floor bus
shows fairly consistent readings.
Single Deck High Floor bus shows inconsistent in data reading mainly because the sensor also picks up the vibration from the bus engine.
Daniel Leow ([email protected])
Conclusion The lateral and longitudinal force are significantly relative to
each other especially for Double Deck and Single Deck High Floor bus. However, this is not much significant for Single Deck Low Floor bus.
Nevertheless, Single Deck Low Floor bus showed higher readings for both lateral (Graph 7) and longitudinal (Graph 8) force. For lateral force, it reached 0.6g. The other two types of buses only reached 0.4g.
As for the vertical force, it is significantly relative to velocity especially for Double Deck and Single Deck High Floor bus. However, this is not much significant for Single Deck Low Floor bus.
As such, the setting of equipment for driver notification alert can be determined from this findings.
Daniel Leow ([email protected])