Kenji-X1, Monitoring and Exploration Robot

Description

Kenji-X1 tele-Robotics Project has started in mid-2018 and was planned to introduce a truly modular systems design which we could use for our applications. But along the way we decided to make it available to others, interested fellow humans and willing to start robotics and similar drone oriented projects. We added lots of functionality which make working with Kenji a truly fun and interesting experience. The project is almost at its completion, we are thinking to try to add VR-Goggles interface or similar. But its still in discussion.
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With development of this robot platform we tried to address issues related to but not only:

- Hardware Customization and Modularity
- Tele-Presence, and Working Remotely
- Piloting Robot via Remote PC-Station
- Data-Acquisition and Evaluation on a Distance also Onboard
- Evaluation of our roboDrive Engine in field conditions and some tests

Details

It seems that there are a lot of robotics and related applications available these days. Starting with the Industrial-Robotics farcry and ending with some weird ones trying to mimic the nature and living organisms, like the ones from Festo.

It seems that robotics in all of its forms is of high demand. Not only for automation but also for entertainment?. It seems that in many situations or projects robotics concept is understood with only 3 things: intel-realisense depth camera, RP-LIDAR and embedded Linux SBC running python, something like raspberrypi or Jetson-nano.

But it's not always that simple as a side-viewer might think, and its not easy to find exactly a perfect robot which will be suitable for your application while also being affordable, and customizable and this and that.

Therefore we decided to start venturing towards our own robotics spinoff, and depart into deep waters while hoping to find our own design and make it the way it would work for us and to learn something along the way, maybe also for others to join and benefit from.

Below some of our nice to have features :

- Be tracked

- with Mast or Tower 360° (continuous rotation)

- with manipulators

- modular and swappable

- remotely and not remotely operated

- be able to integrate with less effort

- affordable and easy to repair

- powerful too

- weather resistant (more or less)

- hackable and expandable

- designed around widely available components

- free to use tool-chains and frameworks /APACHE/ etc.....

Some of above bullet points have been our generic ideas which i could remember. Kenji-X1 adopted design inspired by nature. While hanging out on remote islands somewhere in Andaman Sea, we where hungry and decided to go for crab hunting (°__°). That's right, there where lots of ocean crabs around, and we tried to catch them with hands and bags, but soon we realized that its not that simple. Since then, I was inspired by them. While working on robot's design, I tried to mimic it in analogy of the ocean crab.

Lightweight aerospace aluminum alloys of series ENAW2024 have high-strength to weight ratio. Therefore it was used as base material to produce the carrier-frame. The carrier-frame is used for module-integration. The inner part of the plate is machined out completely and only thin parts are left which carry the entire weight on them. The frame is wide similar to ocean crab's body and locomotion is achieved side-wise positioned actuators. Armature has two pointing out sides which helps Kenji to recover in certain scenarios when there is a dis-balance on a rough terrain.

Lightweight Aluminum mesh or honeycomb layer is then attached to the frame to cover it and also defend the upper systems from a potential damage from below.

The module-integration is normally problematic because the area is limited and there is not much space under the sun.

To overcome this issue, we tried to stack them up, which worked pretty well, and also proven itself positive in the field. Even with high positioned center of gravity it still maintains its balance to a certain point.

The screws and washers make a solid integration of the carrier-frame and tracked drivetrain, which gets installed on both sides for tracked locomotion similar to ocean crab. Motors together with the cables are sealed and made splash-proof / waterproof IP- Rating coming soon (*_*).

What can I say, we did a lot of field testing, results where good, sometimes so so. Was testing our robot-controller (we call it roboDrive) which was capable of keeping-up with the complex hardware system. We did not encounter...

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Kenji-X1 Mechanics Assembly

Lightweight and durable aluminum alloy frame is used for module-integration. The inner part of the plate is machined out completely and only thin parts are left which carry the entire weight on them. The frame is wide similar to ocean crab's body and locomotion is achieved side-wise positioned actuators. Armature has two pointing out sides which helps Kenji to recover in certain scenarios when there is a dis-balance on a rough terrain.

Lightweight Aluminum mesh or honeycomb layer is then attached to the frame to cover it and also defend the upper systems from a potential damage from below.

The module-integration is normally problematic because the area is limited and there is not much space under the sun.

To overcome this issue, we tried to stack them up, which worked pretty well, and also proven itself positive in the field.

Anyway, the main-module (we call it roboDrive) sits on the frame and with 4 - M(3x12) screws and spacers gets screwed to the frame. One thing I really like about working with soft metals and alloys, like Aluminium here, is that even if you make mistakes on design and get angry afterwards, there is always a chance for a brutal workaround by drilling another hole with a regular tools.

The screws and washers 8 - M ( 3 x 12 ) make a solid integration of the carrier-frame and tracked drivetrain, which gets installed on both sides for tracked locomotion similar to ocean crab. Motors together with the cables are sealed and made splashproof / waterproof (IP- Rating coming soon (*_*)).

This boosts the modularity, later if you decide for example, No! I want to remove tracks, I don't want the OFF-Road agility of tracks, and you want the robot to run indoor on smooth warehouse floor, you just have to remove the tracks only removing 8 screws and add wheels. That way you won't need to undergo design changes. Just unplug the connector and unscrew and you're good to go.

And then, you start adding the modules one at a time as in picture below, starting with the drivetrain assembly process.

In most cases there might be a need for some corrections of the bent metal, which can cause the tracks to appear under some angle, but that is a cost of metal production or its deduction :).

Tower-Drive and mastcam module is installed as next, inside the enclosure is a geared stepping-motor with the gearbox and fixation brackets. It has a slider to adjust the positioning. There is a slip-ring installed on the shaft to move the signals around.

I personally am not always satisfied with the metal works, even here in EU it can be pretty horrible mhh.......

As mentioned above, next step is the installation of the roboDrive module.

This robot-controller has been developed by me and Alex, and it does all the low-level communication with the hardware and drivers and everything else. You install this with M - 3x6 screws on the frame and then attach all the connectors and you are ready to go.

Not yet :) ...

If you are still following my long guide on open-source tele-robotics :) kudos to you. After the installation of the module, the entire setup will look like as in picture above or below.

I will tell you what happens next. Because Kenji has 2 x multi-segment fleixble manipulators onboard, we should then proceed to mounting and wiring of these arms on the carrier-frame of the Kenji.

Heavy-Duty mecha-arms :), there is a lot of torque hidden in these two. Therefore if you do something wrong with their assembly and installation they will ruin your day, and maybe you will end up with less fingers :). They are installed on robot similar to the ocean crab, on front, side-wise from head or mast. Arms play a crucial role in balancing and also helping Kenji come out from problematic situation in the field.

If you remember we talked about this modularization thing earlier. So these are attached or detached with

only 2 x M (3 x 20) screws.

Fancy!... okay okay, and some connectors must be plugged-in too...

At this stage carrier-frame, drivetrain, tower-drive, and mecha-arms has been assembled and attached together. Wiring and mechanical fixations points have been tightened and locked. I personally prefer aluminum lightweight bolts and nuts, in most places where I can avoid using the steel ones, which eventually can add-up a lot of weight at the end.

Wiring everywhere, including the arms should be done properly and actually the hole assembly of mecha-arms, will be covered in another topic or later. We have solved this wiring mess by adding a double-bottom. This keeps the endless wires from popping out from everywhere.

So now the mechanical assembly is complete, and time to connect robot-controller to tower and to everything else. That is the drivetrain, mecha-arms, tower-drive, and power - module. The controller PCB-stack is working in combination with the roboDrive engine which as a firmware runs the input-output operations and mostly everything else in between.