Note: Descriptions are shown in the official language in which they were submitted.
CA 02773839 2012-03-30
SPECIFICATION
This invention is an improvement on existing types of manipulators found in
mechanical devices.
Currently, present day prosthetics and remote manipulators usually work only
in one plane of
movement at a time, with a simple "open or close" movement. Their capability
to manipulate
complex shapes is limited and their ability to grip an object is dependent on
small areas of contact.
Present day prosthetic hands, for example, do not come close to mimicking the
versatility of the
human hand.
Robotic "hands" on everything from deep water remotely operated vehicles to
assembly line work
are limited in their ability to use tools and they often require that assembly
parts must be
presented in a particular and often precise orientation. The ability of heavy
earth moving
machinery to pick up a large rock and place it precisely in a truck is more a
test of how the
operator can overcome the limitations of the equipment than anything else.
Many of these limitations can be overcome by utilizing this new design that is
much more flexible,
controllable, versatile and powerful than existing manipulators. At its most
basic level, the
manipulator consists of two types of discs which operate in pairs. One disc
(Figure 1.1) is flat with a
series of electromagnets (a) embedded in it.
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The disc itself is firmly attached to a central semi-flexible tube (e). Wires
controlling the
electromagnets are routed down the inside of the tube to a controller, which
will act as an
interface between the operator and the manipulator.
The bottom side of this disc has a layer of magnetically impermeable material
(g) to prevent
interference with the discs below it.
The second type of disc (Figure 1.3) consists of a disc with a raised upper
surface as seen in cross
section in Figure 1.4. This disc has permanent magnets (b) embedded in it.
When seen in cross
section it is an inclined plane or wedge shape. This disc rotates freely
around the central tube (e)
impelled by changing polarities in the electromagnets (a) in the fixed disc
(Figure 1.1) below. This
rotation causes a bending towards the low side of the wedge and away from the
high side as
illustrated in the enlarged diagram of Figure 2. Figure 3.1 and 3.2 illustrate
how this device is
employed in a prosthetic finger joint. When the high sides of the wedge discs
are alternated the
appendage is straight but when the high sides are aligned, the joint forms a
90 degree bend. Since
joints in a human hand rarely exceed a 90 degree bend, six wedge shaped discs
with a 15 degree
inclination would produce a 90 degree bend. Figure 3.3 is an enlarged cross
section of a 15 degree
wedge. In a prosthetic hand or limb, the discs would be concentrated only at
the normal joint areas
such as finger and thumb joints or ankle, knee, elbow and wrist. The embedding
of pressure and
temperature sensors at appropriate points in the appendage gives important
feedback to the
operator. This is particularly important in establishing and maintaining a
grip on an object. If
movement is to be limited to only one plane, such as in a finger joint, then
programming pairs of
discs to spin in opposite directions limits the movement to one plane. A
central tensioning cable (f)
runs the entire length of the appendage. When a particular configuration needs
to be temporarily
"locked in", the cable, which is fixed at the far end of the manipulator, is
tensioned at the base,
either by a solenoid (i) or by a rotating screw mechanism, giving greater
control.
When discs are placed along the length of the manipulator, the resulting
configurations available
mimic those of an octopus tentacle with its superior gripping power and
directional versatility.
These abilities are particularly useful in everything from remotely operated
vehicles (ROV's), both
on land and in the marine environment, as well as in specialized types of
medical probes. Figures
4.1 through to 4.4 show some of the possible configurations. Figure 4.1 shows
the high sides of the
rotating discs all lined up on one side of the appendage resulting in a
circle. Figure 4.2 shows
simultaneous bends to left or right while Figures 4.3 and 4.4 illustrate right
angled bends to the left
or right, or to front or back as movement is possible in all three planes of
motion.
Spinning and non-spinning discs are protected by a tough synthetic "skin"
(Drawings page two,
Figure 2, "h") in the case of a prosthetic limb, or by flexible metal or
plastic sheathing in the case of
assembly line work or heavy equipment activity. Suitable lubricants inside the
"skin" facilitate the
spinning discs and dissipate heat as well as making them unaffected by the
extreme pressure
found in deep water work.
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While the drawings show only a simple orientation of four magnet and coil
pairs, the number and
placement of them in the discs will vary depending on both speed and torque
requirements.
Likewise the angle of inclination of the circular wedges can be shallow,
producing lower speed of
movement but higher torque, or extreme, resulting in high speed of movement
and much lower
torque.
When used in Prosthetics, the electromagnets are activated in a pre-programmed
manner by
impulses picked up from nerve endings existing in the termination of an
amputee's limb, or in the
case of a quadriplegic, from any remaining muscle fibers that are still
controllable. When materials
are selected for light weight and strength, the power requirements necessary
to operate an
artificial limb incorporating this design should be minimal. The amperage and
voltage requirements
to activate or reverse the polarity of small electromagnets are very small.
However, the resulting
torque produced is very powerful, which results in strong flexing, extending
or gripping
movements. Present day Lithium-Ion rechargeable batteries would be ideal and
can be
incorporated into the limb.
Remotely operated equipment can benefit from this design as movements can be
controlled easily
across severe pressure gradients such as those found in deep water or deep
space vehicles. There
is no need to have penetrating moving parts crossing the "inside-outside"
barrier. Only non moving
electric wires are required and even this potential failure point can be
avoided by using remote
wireless activation.
Heavy equipment operation is moving in the direction of mechanisms which can
be "worn" as
opposed to operated. This manipulator design lends itself readily to this
trend as operator
movements can be picked up by "body glove" equipment or, more likely, by
sensors similar to the
"Kinect box" system in which hand or whole body movements are translated into
equipment
movements. Operator movements are then enhanced, strengthened, speeded up or
slowed down,
as required by this type of manipulator.
