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OMNI-DIRECTIONAL
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OBOTS
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ll the robots introduced in Chapter 7, with the exception of syncrodrive vehicles, have the same deficiency: they cannot drive in all
possible directions. For this reason, these robots are called “nonholonomic”. In contrast, a “holonomic” or omni-directional robot is capable of
driving in any direction. Most non-holonomic robots cannot drive in a direction perpendicular to their driven wheels. For example, a differential drive robot can drive forward/backward, in a curve, or turn on the spot, but it cannot
drive sideways. The omni-directional robots introduced in this chapter, however, are capable of driving in any direction in a 2D plane.
8.1 Mecanum Wheels
The marvel behind the omni-directional drive design presented in this chapter
are Mecanum wheels. This wheel design has been developed and patented by
the Swedish company Mecanum AB with Bengt Ilon in 1973 [Jonsson 1987],
so it has been around for quite a while. Further details on Mecanum wheels
and omni-directional drives can be found in [Carlisle 1983], [Agullo, Cardona,
Vivancos 1987], and [Dickerson, Lapin 1991].
Figure 8.1: Mecanum wheel designs with rollers at 45°
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