This paper deals with a class of mechanical systems, constituted by two composite bodies which interact with each other only during collisions: since only one position variable of only one body is measured, the whole system would not be observable without impacts. Each body is possibly constituted by several masses connected by linear springs, so that the internal deformations can be taken into account (the so-called multiple-degrees-of-freedom impacts). For two relevant and different cases, the structural properties of observability and reconstructibility are studied, and observers are proposed in order to estimate all the state variables, including those that would be unobservable in absence of impacts.

1.
Brogliato, B., 1996, Nonsmooth impact mechanics. London: Springer-Verlag.
2.
Wee
,
L.-B.
, and
Walker
,
M.
,
1993
, “
On the dynamics of contact between space robots and configuration control for impact minimization
,”
IEEE Trans. Rob. Autom.
,
9
(
5
), pp.
581
591
.
3.
Nenchev
,
D.
, and
Yoshida
,
K.
,
1999
, “
Impact analysis and post-impact motion control issues of a free-floating space robot subject to a force impulse
,”
IEEE Trans. Rob. Autom.
,
15
, pp.
548
557
.
4.
Shoji
,
Y.
,
Inaba
,
M.
, and
Fukuda
,
T.
,
1991
, “
Impact control of grasping (robot manipulators)
,”
IEEE Trans. Ind. Electron.
,
38
, pp.
187
194
.
5.
Prokop
,
G.
, and
Pfeiffer
,
F.
,
1998
, “
Synthesis of robot dynamic behavior for environmental interaction
,”
IEEE Trans. Rob. Autom.
,
14
(
5
), pp.
718
731
.
6.
Berghuis
,
H.
, and
Nijmeijer
,
H.
,
1994
, “
Robust control of robots via linear estimated state feedback
,”
IEEE Trans. Autom. Control
,
39
, pp.
2159
2162
.
7.
Canudas de Wit
,
C.
, and
Fixot
,
N.
,
1992
, “
Adaptive control of robot manipulators via velocity estimated feedback
,”
IEEE Trans. Autom. Control
,
37
, pp.
1234
1237
.
8.
Kaneko
,
K.
, and
Horowitz
,
R.
,
1997
, “
Repetitive and adaptive control of robot manipulators with velocity estimation
,”
IEEE J. Rob. Autom.
,
13
, pp.
204
217
.
9.
Nicosia
,
S.
,
Tomei
,
P.
, and
Tornambe`
,
A.
,
1988
, “
A nonlinear observer for elastic robots
,”
IEEE J. Rob. Autom.
,
4
, pp.
45
52
.
10.
Brogliato
,
B.
,
Niculescu
,
S. I.
, and
Orhant
,
P.
,
1997
, “
On the control of finite-dimensional mechanical systems with unilateral constraints
,”
IEEE Trans. Autom. Control
,
42
(
2
), pp.
200
215
.
11.
Tornambe`
,
A.
,
1999
, “
Modelling and Control of Impact in Mechanical Systems: Theory and Experimental Results
,”
IEEE Trans. Autom. Control
,
44
, pp.
294
309
.
12.
Menini
,
L.
, and
Tornambe`
,
A.
,
2002
, “
State estimation of (otherwise unobservable) linear mechanical systems through the use of non-smooth impacts: the case of two mating gears
,”
Automatica
,
38
(
10
), pp.
1823
1826
.
13.
Menini
,
L.
, and
Tornambe`
,
A.
,
2001
, “
Velocity observers for linear mechanical systems subject to single non-smooth impacts
,”
Syst. Control Lett.
,
43
, pp.
193
202
.
14.
Menini
,
L.
, and
Tornambe`
,
A.
,
2002
, “
Velocity observers for non-linear mechanical systems subject to non-smooth impacts
,”
Automatica
,
38
(
12
), pp.
2169
2175
.
15.
Brogliato
,
B.
, “
Some perspectives on the analysis and control of complementarity systems
,”
IEEE Trans. Autom. Control
,
48
(
6
), pp.
918
935
.
16.
Vidyasagar, M., 1993, Nonlinear systems analysis. Englewood Cliffs, N.J.: Prentice-Hall.
17.
Kailath, T., 1980, Linear systems. Englewood Cliffs: N.J.: Prentice-Hall, Inc.
18.
Tornambe`
,
A.
,
1992
, “
High-gain observers for nonlinear systems,”
Int. J. Syst. Sci.
,
23
(
9
), pp.
1475
1489
.
19.
Chen, C. T., 1988, System and signal analysis. New York: Holt, Rinehart and Winston.
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