Let me turn the agent's speed up a little.
We've made the power loader safer.
Now let's make it smarter.
This episode is sponsored by Aliens: Fireteam Elite.
Ambitious projects like the power loader all start somewhere.
Back in January of 2019, we released the first episode of
the Aliens Power Loader series.
We had limited resources back then and very limited space.
We had no right to even be considering a project of this scale.
But we didn't let that stop us.
We broke up the project into multiple steps, episode by episode. From the arms
to the grippers, to the body, to the legs. From the old garage to the new shop.
It's crazy to think that nearly three years later through motivation,
passion, blood, sweat, and tears.
I now stand in front of this ridiculous machine straight out of science fiction.
Join us as we inch closer and closer to the finish line.
And don't forget to grab your very own limited edition power
loaded t-shirt available now on Hacksmith.store.
Working on or around this thing is pretty scary.
There's no insurance,
no regulations, and no room for error.
It's all on me.
There's currently nothing stopping the system from injuring the pilot.
So our first line of defense is emergency stops, a kill switch for the pilot, which
stops all motion on the entire system.
But what if there is no pilot, as you saw in the last episode, we can operate
this thing with a PS4 controller, but what if the remote disconnects?
What if we have a runaway power loader situation?
For this, we've partnered with Fort.
Fort makes wireless safety systems, and they've provided us with a safety remote control.
Basically it's similar to the PS4 controller, but it has a lot of extra
safety features such as drop detection, communication monitoring, and
a built an e-stop. Fort also sent over their wireless emergency stop, which
allows a spotter to stop the system
if they see anything going wrong.
Finally, all of this controls three safety relays, which guarantee that
if an e-stop was to be pressed, power would be cut to the entire system.
Stopping it immediately.
Let's get everything installed.
If you'd like to see our updated schematic diagram, make
sure to check out the maker.io link in the description below.
For the best signal
we're going to mount this on the very top.
People often say that humans only have five senses, false.
One sense we often overlook is called proprioception.
Proprioception our ability to feel where our limbs are, even if we can't directly
see or hear them, for example, this, I can do this even with my blindfold
on, because my body knows where my limbs are. For the power loader, not so much.
Let's change that.
Machines only know what they're told.
So we have to tell it where the position of this arm is for example.
To do this, we'll be using a rope potentiometer.
This sensor provides a potential difference or voltage based
on the length of its rope.
By adding one of these onto every individual joint, the power loader
will now have proprioception.
In technical terms, this is called a closed loop feedback system.
And there we go.
That's one rope potentiometer fully installed.
Now when the power loader moves, its wrist it's going to pull on this rope,
it'll know exactly where the wrist is at all times.
Now we just need to do it twelve more times.
Power loader technician safety training. Scenario one, wireless e-stop.
The operator of the power loader has fallen asleep at the wheel, silly operator.
Luckily, we have a spotter on watch at all times
during operation, he safely stops the power loader with
the Fort wireless e-stop.
Scenario two, new safe controller drop detection.
In this scenario.
Bogdan is doing a great job at operating the power loader.
No runaway power loader this time.
Oh wait, what's this, in classic Hacksmith fashion
it's chaos in the shop today.
All thanks to Fort,
everyone is safe, including the power loader.
Scenario three, loss of signal.
Bogdan forgot to charge the controller like a simpleton.
What is the power loader going to do this time?
Nothing.
All thanks to the Fort safety controller with loss of signal detection.
And now a word from our sponsor.
We can get so caught up in engineering and manufacturing, this power loader
that sometimes it's easy to forget that we're actually building a
real life version of a mega prop from one of the most iconic science
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We've made the power loader safer.
Now let's make it smarter.
I'm going to talk to you about inverse kinematics.
So what is inverse kinematics?
Well, it's a bunch of math.
And is it interesting?
Well, if you asked me yes, if you asked anyone else, no.
Now I'm going to try to keep this interesting, let's start with forward
kinematics, forward kinematics is how we figure out where the gripper is
and real-world positions and inverse kinematics is how we figure out
the joint angles to get in there.
I'm going to use this lamp as an example of why we need to inverse kinematics.
In order to know what the lamp head is,
we first need to know the angles of joint A, joint B,
and the lengths of both of the joints as well.
This lamp arm is a gross over simplification of the power loader
arm, but it works for this example.
If we move it away from me along the X axis, you notice that the angle of joint
A and B both change, inverse kinematics is what lets us figure out those angles.
The math could be done by hand for every move we want in the power loader to make
but that would be slow and stupid.
So we're going to have the computer do it for us. To make use of this math,
we need an operating system, enter ROS. That's what's going to kill me.
We can integrate our joysticks, the inverse kinematics model, the
safety system, and it all runs on the revolution Pi Coon bus system.
We introduced in the last episode.
Now take it from here, Anmol.
Hey, I'm Anmol
and I'm a co-op here at Hacksmith Industries and today
I get to talk to you about Ross.
AKA the robot operating system.
ROS is essentially a framework of software packages, such as the robot hardware
interface, the robot controllers and the communication infrastructure that
allows everything to work together.
Ben has given me a ton of data.
I'm going to implement Ross to process all this data and send
commands to the power loader.
This will let the power loader move safely and accurately.
We have all the necessary components to run the software packages
in this box that Ben built.
You know how we said we're going to make the power loader smarter,
we gave it a brain.
Here are the connectors for the power loader.
On the other side, we have our secondary computers, one to manage all the
auxiliary IO and one to manage all the Ross applications, over here, we
have the power distribution system, and finally we have the relays.
They allow us to control all the auxiliaries and the primary belts in order
for us to leverage the precise control inverse kinematics towards us, we're going
to need a more refined hydraulic system for the power loader.
Right now the power loader joints are either on or off, moving at
full speed or completely stopped.
This is called digital control and it's fine for most applications,
but for us, we want smooth, precise control of every individual joint
all at the same time and to do this, we need proportional valves.
It's a valve that allows us to proportionally control exactly how
much fluid flows through it, depending on how fast we want things to move.
Let me just show you an example.
Here's a perfect example of a digital valve.
There's either no fluid flowing or all of it is flowing.
On the other hand here we have an example of a proportional valve.
We can have a lot of flow, a little bit of flow, all the flow, none of
the flow. It's completely controllable.
We partnered with Bosch Rexroth who sent us over some of their
amazing proportional valves.
These valves have a low hysteresis, a low latency and a high
flow, and they're direct drop-in replacements for our current valves.
So we got to pull those ones out.
Put these ones in, update our software and we should have smooth,
precise control over every joint.
Alright.
We have the new Bosch Rexroth proportional valves installed into this hand
and the old on-off valves in this one.
Let me show you how they compare.
Let me show you the old arm.
We can move up and down no problem.
And we can move left and right.
But as soon as we try to move the two together, to move up and to
the left, for example, our arm stops moving up and that's because all
the hydraulic flow is going to the path of least resistance, which in
this case is the pan wrist cylinder.
Let's compare that to the new valves.
If we use the new valves,
again, we can move up and down and we can move left and right.
But the difference is with the new valves, we can now do both
of those things at the same time.
Watch this.
That is so much better.
I have really fine control
and again, for comparison, the old arm, as soon as they start moving to the
left, it completely stops moving up
it actually starts dropping.
To show you just how much of an improvement, the smoothness, the
new proportional valves have made,
let me turn the agent's speed up a little,
Alright. First off, the new proportional valves.
That looks great, but let's see how the old valves preform.
Yeah, I think I'm going to stop using those old ones.
Alright so in my hopes of trying to demonstrate what I was talking about, uh, I
think I overdid it a little bit.
That motion was actually so erratic on the old valves that we actually bent the bicep.
And that arm is hanging on by a thread now.
I guess the next step is to replace all the valves with
Bosch Rexroth, proportional valves, add some software limits,
so this doesn't happen again.
That's a future Bogdan problem though.
So thanks for watching and I'll see you in the next episode.