![](bg6.png)
0 10 20 30 40
−0.2
0
0.2
0.4
0.6
0.8
Sliding surfaces s
1
and s
2
time [s]
s
1
, s
2
s
1
s
2
(a)
0 10 20 30 40
−0.2
−0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
Separate distance
time [s]
d tilde [m]
(b)
0 10 20 30 40
−20
0
20
40
60
80
100
120
Relative bearing (ψ tilde) and relative orientation (φ)
time [s]
ψ tilde, φ [deg]
ψ tilde
φ
(c)
Figure 9: Simulation II - Sliding surfaces s
1
and s
2
, separate
distance (
˜
d), relative bearing (
˜
ψ) and relative orientation
(φ).
4 CONCLUSIONS
In this paper is proposed a sliding mode forma-
tion tracking control scheme of nonholonomic mobile
robots. The leader and follower are a skid-steering
mobile robots. The desired formation, defined by two
parameters (a distance and an orientation function) is
allowed to vary in time. The effectiveness of the pro-
posed designs has been validated via simulation ex-
periments.
Future research lines includethe experimental val-
idation of our control scheme and the extension of our
results to skid-steering mobile robots. For the sake of
simplicity in the present paper a single-leader, single-
follower formation has been considered. Future in-
vestigations will cover the more general case of multi-
leader, multi-follower formations.
ACKNOWLEDGEMENTS
This work was supported by CNCSIS-UEFISCSU,
projects PNII-IDEI 506/2008 and PNII-IDEI
641/2007.
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