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I thought it would be useful to provide some examples of
commercially available kinesthetic or force feedback
haptic devices so that you could see the range of things
that are out there and the incredibly creative designs
and successful commercial products
that people have created.
Here are some examples of manipulandums.
These are all commercially available, and the ones on
this page are pretty expensive, ranging on the
order from about $20,000 to $60,000, depending on the
degrees of freedom that it has.
First we have the Omega haptic device from Force Dimension.
This is a somewhat unusual design in the haptics world
because it has this delta configuration.
You can see a linkage here, a linkage here, and a
linkage back here.
These three linkages all come together at a point where the
user grasps right here on this ball.
And this haptic device has its motors mounted here on this
end plate back here.
The nice thing about this haptic device is that the
motors are all grounded; that is, none of the motors move as
you move the mechanism.
And that is a somewhat hard design challenge for a device
that has three degrees of freedom; i.e., one that moves
in x, y, z in Cartesian space.
The other nice thing about this device is that because it
has this delta mechanism it has a parallel structure, and
that allows it to render somewhat stiffer environments
than many other types of haptic devices.
Let's look at another type of manipulandum.
In this case it's more of a serial rather than parallel
chain mechanism, although there are some parallel
components as you can see from these two linkages up here.
And this one is the Phantom Premium 1.5, originally
designed and marketed by a company named SensAble, and
now that company was bought out and it's sold by a company
called Geomagic.
It's called a 1.5 because there are some different sizes
of Phantom Premiums, and you could think
of this as a medium.
The 1.0 is the small, and there are also some much
larger ones.
The 1.5 is a medium-sized haptic device.
It consists of, I like to think of it as two mechanisms
which are attached together.
The first part of the mechanism is a 5-bar device.
This is a classic kinematic structure which, if you're
interested you can look up 5-bar kinematics and you can
see what that looks like.
Basically what it does is it provides two degrees of
freedom out here at the end point.
It allows it to move up and down, and it allows it to move
in and out, towards the hand and away from the hand.
So that 5-bar gives you two degrees of freedom, and that's
through some mechanisms here and the
motor's moving back here.
Unlike the Omega, the motors here actually themselves move.
They travel back and forth on this drum as you move this
haptic device around the workspace.
And so that does increase the inertia a little bit because
the user can feel those motors moving.
However, as with many kinesthetic haptic devices,
people don't tend to move around the workspace very
fast, so the inertia is relatively low.
Because there's not as many joints as there is on a delta
configuration, there aren't as many places on the mechanism
that can generate friction, and so this type of
manipulandum can be lower friction than more parallel
type mechanisms.
But I did say it has three degrees of freedom.
So it can move in x, y, and z in Cartesian space.
That third degree of freedom comes from rotation.
There's this 5-bar mechanism here, but then this whole
thing is mounted on another drum which can move back and
forth, and so that gives you a third degree of freedom.
This device is also shown with an extra gimbal mechanism
here, a kind of wrist that the user has the
stylus attached to.
This gives it even another three degrees of freedom, but
in this case the three degrees of freedom are only being used
for position sensing.
There's no force or torque feedback coming from the
gimbal mechanism.
It does allow the user to more freely move the stylus around
the workspace, because as you might know, moving a stylus
around a workspace, if you want to move to any position
and orientation, requires six degrees of freedom.
So it's nice that you can move it in this way.
But I say it only has three degrees of freedom because
that's the degrees of freedom of force feedback that the
device has.
In many haptic devices that are commercially available
like the Phantom, and this includes the Omega from Force
Dimension as well, you can mount other things on the end
point here.
So the Omega also has a system where you can
add a gripper here.
And they also have other haptic devices that have
higher degrees of freedom by mounting wrists either with
just position sensing or also with torque display
capabilities that can give it higher number
of degrees of freedom.
And that leads us to our last device on this slide, which is
the Virtuose from Haption.
In this company, they've designed a haptic device that
actually has a full six degrees of freedom of force
and torque feedback.
It has a lot of the mechanisms that provide three degrees of
freedom back here in the base, and then the fourth, fifth and
sixth degrees of freedom are resulting from motors that are
mounted in the handle and up along this last shaft.
You can see that actually each of these devices has a
different way of having user contact with the mechanism.
Here is a ball that the user holds onto; here's a stylus;
and this is more like a handle that the user can
grab onto and grasp.
Let's go to the cheaper range of manipulandums now.
And the first two I purposely picked because they are
essentially cheaper versions of the more expensive haptic
devices shown on the left in the previous slide.
The first one is the Falcon.
This Falcon haptic device-- there are actually two of them
shown here, device one and device two--
are based on the same delta type mechanism as the Omega
shown in the previous slide.
But they're smaller, they have a smaller workspace, they have
less powerful motors, and they have more friction and more
inertia on them than the really fancy research grade
haptic device.
However, these devices can be had for a few hundred dollars.
Here's an example of two of them, and it's useful to show
these two because they have different
end-effectors on them.
This one has a ball, which is similar to the Omega on the
previous slide.
This one actually has a gun type of gripper.
As you can imagine, these less expensive haptic devices are
popular for video games.
Another example, this one built on the Phantom Premium
haptic device, is another device called the Phantom, but
this is called the Phantom Omni, although now, because
SensAble was bought by Geomagic, the latest name for
it is the Touch.
So the Geomagic Touch haptic device is how
it's marketed now.
This one also has that same 5-bar and then extra
rotational degree of freedom, but you can see that it's been
made smaller.
It also has less powerful motors.
It's encased in nice plastic, so it looks more like a
commercial product.
It still has three degrees of freedom of force feedback.
And here there's still a gimbal mechanism here which
provides an additional three degrees of freedom of position
sensing, but you're still limited to only three degrees
of freedom of force feedback.
So three degrees of freedom of force feedback in this case.
This device by the way is on the order of a couple thousand
dollars, so much more expensive than the Falcon, but
of course an order of magnitude cheaper than a
Phantom Premium.
Finally, going way onto the commercial end of force
feedback haptic devices, let's look at the
Sidewinder from Microsoft.
This device, I'm not sure how commonly available it is
anymore, but it is only a two degree of
freedom haptic device.
It can move as a joystick, left and right
and back and forth.
So unlike these three degree of freedom haptic devices, it
has two degrees of freedom.
It uses a type of spherical mechanism inside, which
basically means that the joystick is not moving
strictly in Cartesian space, just x and y, but they're
actually moving along arcs.
And this is actually quite similar to
how your hapkit works.
If you move the handle of your hapkit back and forth, you'll
see that it moves along an arc.
You might think of that as, I guess, the cylindrical
mechanism, just in one degree of freedom.
If you take that concept and you move it to two degrees of
freedom, then you get a spherical mechanism.
This haptic device is on the order of $100 or so.
And again, it's sold for video gaming
purposes, as is the Falcon.
I would say that the Omni or Touch is used more by
researchers and people who do computer-assisted design in
virtual environments.
Those were all manipulandum haptic devices, and I should
emphasize that there are many, many other commercial
products out there.
Those are just some canonical examples.
I'll also mention a few gripping or grasping type
interfaces.
There are not a lot of these which are
commercially available.
Sometimes there are devices which are actually attached
onto another kinesthetic haptic device, like I
mentioned the Omega has a gripper attachment which is
optional that you can purchase.
But here are some examples of some
grasping-capable haptic devices.
This first one is a custom haptic gripper that was
actually designed by my laboratory several years ago,
where we took a Phantom Premium haptic device and
added another motor and some mechanisms in order to give
the user force feedback between the fingertips.
So this is a custom laboratory-designed haptic
gripper that we use for research.
Here's an example of a commercial product that
provides gripping.
I guess I say it's single finger, but it's really single
grasp because there are forces being applied to two fingers;
to this finger, and to this finger.
And the way in which this one works is similar to a bicycle
brake cable.
Around the end of the finger is a little cuff which is
attached to a string, which runs through a tube, all the
way down here, eventually to some motors which the user can
wear in a backpack or can be sitting on the table.
And this is done for both the index finger
and the thumb here.
And so if you apply force feedback by pulling back on
the cables here and here, the user feels as if they're
grasping a virtual object because the fingers cannot
move toward each other.
This is a true within grasp force feedback haptic device
because, at least as shown in this picture, there's no
grounded force feedback provided.
It's only an ungrounded force feedback that you get between
the fingers.
This picture here shows the master of the da Vinci
surgical system.
This system actually doesn't have programmable force
feedback on the gripper, but I thought I would point it out
because it has a non-programmable
type of force feedback.
It actually has springs which are inside the gripper, so
that when the user squeezes they feel a force to help let
them know how hard or how far they've squeezed.
So this one just has real springs, not programmable
force feedback.
But it's interesting that many surgeons who have used the da
Vinci surgical system have commented to me how useful
those springs are because the force that you feel from the
springs gives you this extra knowledge about your hand
configuration.
So not a true haptic device in terms of grip force feedback,
but nonetheless a grip or grasp interface which provides
forces in a useful way.
Finally, let's just give a few examples of exoskeletons.
I mentioned in the previous video segment that there is a
KINARM exoskeleton from a company called BKIN
Technologies which uses a pair of planar exoskeleton trays on
which the user can lay their arms.
So this device is a relatively simple exoskeleton.
There are many, many more complex exoskeletons that have
been designed by researchers, but most of them are not
commercially available.
Exoskeletons for walking or running or carrying heavy
objects have gone under a lot of development over
the last few years.
In addition to these older examples from Harvard
University as well as DARPA, which helps soldiers in this
case carry very heavy loads, there's been a lot of press
lately about research groups at Berkeley and Vanderbilt and
other places developing exoskeletons to help
paraplegics walk.
So that's a great thing to look up if you're interested
in exoskeletons.
The difference between these arm exoskeletons and these
body exoskeletons is that these body exoskeletons are
more about providing assistance in walking or
movement, whereas these arm exoskeletons can be about
providing haptic feedback for rehabilitation.