Abstract
The realising of the great benefits of odometrically-controlled, freeranging, automatically guided vehicles has been prevented by the lack of an adequate secondary ‘absolute’ vehicle location technique, required to overcome the cumulative errors inherent in odometry. In this paper the sources of odometric error are discussed, and the resulting positional uncertainties investigated. The dominant amongst these is identified as being the uncertainty in the lateral location of the vehicle, and this is quantified as a function of odometric error. A location technique addressed specifically at this uncertainty has been devised and constructed, employing linear arrays of light sensitive elements and a narrow light beam. This system and its associated electronics and software is described.
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Abbreviations
- θ:
-
Wheel rotation
- r w :
-
Wheel rolling radius
- R :
-
Radius of curvature of vehicle path
- W :
-
Effective lateral wheel separation
- γ:
-
Ratio of wheel rotation rates
- x, y :
-
Cartesian spatial co-ordinates
- l :
-
Distance travelled by vehicle centre
- L :
-
Vehicle length
- ϕ:
-
Vehicle heading deviation
- ε:
-
Vehicle lateral deviation
- δ 1 δ 2 :
-
Illuminated detector locations
References
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Ren, Y.T., Walker, S.P. Position determination of automatically guided vehicles. Int J Adv Manuf Technol 1, 45–53 (1986). https://doi.org/10.1007/BF02601552
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DOI: https://doi.org/10.1007/BF02601552