Part
: PIONEERING STUDIES ON COELACANTH
COELACANTH FLESHED-FIN,
HUMAN ARM AND HUMANOID ROBOT ARM
Minayori Kumamoto
Professor Emeritus,
Kyoto University
hrough these three terms of the title, there is a common
keyword of “antagonistic pair muscle control”. Coelacanth
leshed-in consists of the same skeletal structure as is seen
in animal extremities, namely, scapula (pelvis), upper arm
(thigh) and forearm (shank). Based on motion analysis data
of Lancelet swimming form, it was suggested that functional
unit muscle of Lancelet will consist of hypothetical three
joint muscles. Further, it has been conirmed that Lancelet
swimming form could be reproduced with a mechanical
engineering Lancelet model provided with seven antagonistic
pairs of artiicial muscles, where seven neural networks for
the antagonistic pair artificial muscles were sequentially
activated. A leshed-in of Osteolepis of primitive ish might
be built with functional unit of hypothetical three joint
muscle, and might result in a three joints structure. When
primitive fish has been evolved into primitive amphibian,
their extremities of primitive amphibian had basically three
joints structure and certainly, have been provided with one
antagonistic pair of bi-articular muscles and two pairs of
antagonistic mono-articular muscles, during landing. That
is why every quadruped and biped animals in the present
world, not only in mammals, but also in birds, reptiles, and
even amphibians have the bi-articular muscles in addition to
the mono-articular muscles. It has been also conirmed that,
when a mechanical robot arm model equipped with the biarticular actuators as well as the mono-articular actuators
was phase differently drove with the same neural network
as was used for Lancelet model, the robot arm model could
demonstrate perfect humanlike control properties and
output force properties. Humanoid robot arm provided
with bi-articular actuator, exactly a real humanoid, not like
Honda Asimo, could exert perfect humanlike smooth and
rapid movements and unique control properties.
Through these three terms of the title, there is a
common keyword of antagonistic pair muscle control.
It is well known that all quadruped and biped terrestrial
animals, not only mammals but also reptiles, birds and
even amphibians have an antagonistic pair of bi-articular
muscles in addition to antagonistic pairs of mono-articular
muscles in their extremities. Whereas, ish has not any biarticular muscle. As to unique functional properties of the
bi-articular muscles, we have reported that the existence
of bi-articular muscle contributed to exert stiffness and
trajectory control of the endpoint of the extremities,
resulting in smooth, rapid and precise movement without
1)
position feedback signal from the endpoint . Further, we
3
3
3
3
S
3
3
3
1
2
2
4
2
2
S
2
1
have reported that the antagonistic pair of bi-articular
muscle demonstrated perfectly coordinating activity with
two pairs of antagonistic mono-articular muscles acting
on the both end joints, and contributed to output force
control and output force direction control at the endpoint
2,3)
(Coordination Control) . From the viewpoint of biological
evolution, it would be sure that primitive amphibian first
successfully installed the antagonistic pair of bi-articular
muscles as well as the antagonistic pairs of monoarticular muscles and acquired coordinating control of the
group of antagonistic pair muscles, when the primitive
fish succeeded to land and evolved into the primitive
amphibian (Fig.1).
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Part
: PIONEERING STUDIES ON COELACANTH
Fig. 1. Appearance of Bi-articular muscle in Biological Evolution. (Detailed explanation in the text.)
The landing drama would be happened at the end
of Devonian period (Fig. 1). In the Devonian period,
Coelacanth branched off from Osteolepis and is still living
in the present world (Fig. 1), and show us the living bold
leshed-in. A skeletal structure of the leshed-in of both
living and fossil Coelacanth, leshed-in of the primitive ish
and fossil extremity of the primitive amphibian showed
almost the same three joint structure as is seen in the
terrestrial animal extremity in the present world (Fig. 2).
Why do they have a 3-joint structure? It should be noted
that they should be controlled by their own neuromuscular system.
Coelacanth is swimming mainly by drift with bold
fleshed-fin. 3.8ml/kg/hour O 2 consumption, whereas,
4)
42.5, in trout and 484, in tuna . According to the Newton
separate volume, spindle shape thick body muscle of
Coelacanth is covered by rough surface of scale. The
structure of rough surface scale could be possible to
achieve 21-26m/sec/sec acceleration. But so far, such
a rapid swimming has not been obser ved in living
Coelacanth.
42
T h e C o e l a c a nt h , Fa t h o m t h e My s t e r y 2 0 0 7
Fig. 2. Similarity in skeletal structures of fleshed-fin and animal
extremity.
A: Coelacanth caudal in4) B: Coelacanth fossil
C: Primitive ish, leshed-in5) D: Primitive amphibian hind-limb5)
Lancelet, appeared in early Cambrian period, more
than 100 million years earlier than Coelacanth, is still
alive in the present world, and show us perfect S wave
swimming form (Fig. 3).
Fig. 3. S wave swimming form of Lancelet.
3 bellies and 2 nodes were seen and S shape bilateral symmetry form
was kept perfectly during forward and even backward swimming.
It has been also confirmed that, when a mechanical
robot arm model equipped with the bi-articular actuators
as well as the mono-ar ticular actuators was phase
differently drove with the same neural network as was
used for Lancelet model, the robot arm model could
demonstrate per fect humanlike control proper ties
and output force properties (Fig. 1). Humanoid robot
arm provided with bi-articular actuator, exactly a real
humanoid, could exert perfect humanlike smooth and
rapid movements and unique control proper ties. A
submerged working robot provided with bi-articular
actuators will be helpful for deep water investigation (Fig. 5).
Fig. 5. Submerged working robot provided with bi-articular actuators.
Fig. 4. Functional unit muscle arrangement proposed for Lancelet.
Not less than 7 and not more than 8 units should be arranged
antagonistically as is shown in Fig.4.
Surprisingly, they have highly developed striated
muscle, almost the same electron microscopic level tissue
structure as is seen in higher animals. There was not any
anatomical evidence of a neural network for myomeres
of Lancelet. However, an appropriate neuro-muscular
unit system was certainly needed to achieve perfect
symmetrical S wave swimming form. Based on detailed
motion analysis data of Lancelet swimming form, it was
proposed that 7 or 8 antagonistic pairs of functional unit
muscle are arranged as is shown in Fig. 4. The functional
unit muscle will be hypothetical three joint muscle (Fig. 4).
Further, it has been conirmed that Lancelet swimming
form could be reproduced with a mechanical engineering
Lancelet model provided with seven antagonistic pairs
of artiicial muscles, where seven neural networks for the
antagonistic pair artiicial muscles were time sequentially
activated (Fig. 1). A fleshed-fin of Osteolepis of primitive
fish and also Coelacanth might be built with functional
unit of hypothetical three joint muscle, and might result
in a three joints structure. When primitive fish has been
evolved into primitive amphibian, their extremities of
primitive amphibian had basically three joints structure
and certainly, have been provided with one antagonistic
pair of bi-articular muscles and two pairs of antagonistic
mono-articular muscles, during landing. That’s why every
quadruped and biped terrestrial animals in the present
world have the bi-articular muscles in addition to the
mono-articular muscles.
Referring again to Fig. 1, from the view point of
biological evolution of motion control, an examination
of muscular architecture of Coelacanth fleshed-fin, if
possible, might shed light on structural changes from the
leshed-in to the primitive amphibian extremity during the
landing drama.
References
1) Kumamoto, M. et al.: Control properties induced by the
existence of antagonistic pair of bi-articular muscles.
Human Movement Science. Vol.13, pp.611-634, 1994.
2) Fujikawa, T. et al.: Functional coordination control of
pairs of antagonistic muscles. Transactions of the
JSME. Vol.63, pp.769-776, 1997.
3) Fujikawa, T. et al.: Output force at the endpoint in
human upper extremities and coordinating activities
of each antagonistic pair muscles. Transactions of the
JSME. Vol.65, pp.1557-1564, 1999.
4) Newton, separate volume. Newton Press, Sept. 10th,
1998.
5) Corber t, E.H. et al., Colber t’s Evolution of the
Vertebrates. Japanese Edition translated by M. Tasumi,
Tsukiji Shokan, Tokyo, 2004.
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