# Finished the rover chassis last night



## griz (Jan 9, 2006)

Sorry for the cell phone pic I need to get the beast outside for some decent shots. Finished up the chassis last night. Going to wire up the motors today and test those. Just waiting on the Zed camera to start coding.



















Griz


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## griz (Jan 9, 2006)

*A few more pics*





































Heading to the hobby shop tomorrow to find a lipo for the computers. They make some 5500mah units for droids now. The Jetsons will tolerate up to 16v so they will work fine at 14.5v topped out. Keeps the motors from putting spikes and causing havoc with the computers if the power supplies are separate. Gotta watch out for ground loops however. This isn't my first rodeo so I should be ok there. However I've let the smoke out of lots of stuff in the past 

Griz


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## griz (Jan 9, 2006)

Installed the motor controller and lipo battery today. Lipo's are a lot more complicated to mess with than the NIMH I used to use. But man do they pack a punch. 5200mah in a very small package. Just need the wiring harness makings for the motors and it will be time for a smoke test.

Griz


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## MichaelW (Jun 16, 2010)

Griz, what will you be using this for.


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## dbarham (Aug 13, 2005)

MichaelW said:


> Griz, what will you be using this for.


That's what I was thinking


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## stargazer (May 24, 2004)

He has a NASA contract to build the next Mars Rover 
Boy, when you tinker in the Garage, you dont mess around


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## griz (Jan 9, 2006)

*Lots of stuff*

Eventually I want to turn my mobility scooter into the ultimate shooting platform. But I don't want to be sitting on it during testing so this is the test bed. I've also been into robotics since the 80's. I did a car was robot one time had a HeathKit Hero2000 with the arm and all the stuff you could buy for it. We went camping one weekend and someone broke in and took it. The car wash deal was bad as well they went out of business owing me about 10K. My rough initiation into the business world.

But I just like to tinker and I've always been fascinated with computer vision and neural networks/AI. All the stuff I am really interested in is in this machine. Cameras, photography and processing, computer control of motors and computer communications, and it lights up my design/mechanical circuits too. Its just a big r/c crawler with its own brain. Actually you can plug a reciever into the motor controller and use it just like a r/c vehicle.

As far as photography I want to take it to lots of places and let it roam around taking pictures and video. 3-D video from the Zed at up to 2K res. And all the stuff it can do with that data. Point clouds depth maps the input necessary for autonomous operation. Between the gps inertial motion unit and the encoders on the back wheels it will know exactly where it is and what pose its in at all times. That part of the equation is called odometry. The part that does the actual navigation is called SLAM. Simultaneous location and mapping. By mapping we are talking a occupancy map. The Zed divides its field of view up into a grid. Then analyzes the image and either assigns filled or unfilled to each box in the grid depending if it detected an object. Each pixel has depth information in addition to rgb info. A little AI and image processing turns that into objects. As soon as an object moves from frame to frame it will start calculating its Euler route speed and all that to determine where its going to be on the next frame. As you can imagine this can get quite complicated if say there are a bunch of people milling about. So you need processing power and the nvidia Jetson boards are the only embedded cards with the horsepower to handle it. I have 4 of them in a cluster so when I found out the Zed was compatible I decided to try and make it happen.

ROS (Robot Operating System) was designed at a major university then put into the public domain. Its the backbone of the whole deal. Very robust with excellent tools and drivers for pretty much any robot or device out there.

The company Actobotics that makes all the metal parts has the makings for all kinds of motorized camera goodies. I plan on having a slider and I already have an X-Y turret to put cameras on. So next time I go to Utah I'll turn the thing loose on some trails I can't get down any more. I'll have FPV (first person viewing) on it by then so I can pick the shots or tell it to come on home. I'm going to program it to turn back at half battery capacity. I'm using a pair of 5.2amp 14v lipos. So runtime will be between 2 and 3 hours before I get the solar cells onboard. Going to use deer feeder panels. They are the right size and cheap. The mast will have a pair of them on a shaft so they can tilt and also rotate so they are always pointed at the sun. And just for grins I'm going to install the 10 channel analyzer I have and have it stream telemetry back to me on all the systems. Power motors and the communications channels. No telling what else its pretty generic and can be adapted to lots of uses. I plan on entering it in the Autonomous vehicle contest they have in Colorado every summer and possibly some rescue but challenges as well. I'll have to add in face recognition and neural networking stuff to do the rescue challenge.

I've been doing nothing but photograpy of some form or another for several years now. I was getting burned out. I needed something I could work on no matter what the weather or amount of clouds. I love programming and working with circuits so this is perfect. I had the money saved up for a astro ccd already had the computers so outside of the Zed it didn't cost me that much to build. And I have a renewed enthusiasm for photograpy after taking a break so its all good.

Griz


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## griz (Jan 9, 2006)

*New Version*

Well I made a bunch of changes in the chassis. Went to carbon fiber tube instead of the aluminum. Much lighter. Also came up with an elbow for each end of the outriggers so I can bend those ends down at an angle to get greater ground clearance. Motors were too small so they have been replaced. The old motors are being used for other stuff so it wasn't a huge loss. Came up with different pivot for suspension basically redid the whole chassis.










New base supports. The base is supported by a pair of 1"carbon tubes with clamps on each end. 3 screws loosened and you can remove the base and all the electronics.










This is the elbow I came up with for the outriggers. The bearings are in the middle of the tube now as well.










Version 2 of the rover.










The Zed camera is awesome. Easy to get it installed in ROS. They included a ROS driver in the newest version of the SDK.










This is the new rear truss/suspension. Easy to adjust the level of the base as the whole thing slides up and down on the mast.










These are the proper sized motors. Found a web page you work through and it gives you the required torque to get it done. These are 400oz/in 435rpm 20:1 gearmotors. I have about 150oz/in in reserve with these puppies.










And this is the home screen for the onboard touch screen.










Looks like the F1 race this weekend is going to be very soggy. Doubt I'll even try to go until Sunday. My luck I bought tickets early this year and sure enough a monsoon is forecast  At least I have the rain gear for my camera I bought for MotoGP. Rented a 1.4x tele this time as well. Problem is going to be muddy pathways for the scooter. Not going to be able to get to some of my normal spots. I'll have to stay around the hairpin where the pathway is paved. Oh well the spray should make for some killer pics.

Griz


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## griz (Jan 9, 2006)

It has 360deg lidar now. Just finished it up tonight Met up with some Italians on Twitter that do robotics in a big way. One of them has a Jetson bot with the Zed camera as well. Anyways they have a navigation and motor controller board that has the ROS driver already written. So I picked up a pair of those and am using the roboclaw for the lidar and eventually a leveling mechanism. Put a gear on the main shaft and use a motor and the IMU readings to adjust the level of the payload.










Its a Pulsed Light LidarLite v2 500khz sample rate. Running it at about 75rpm but will go up to 200-300rpm as soon as I modify the code to turn on the high speed mode. The code is for a v1 lidar which doesn't have the hi speed mode. Its running on a slipring 22mm base and 8mm axle. About the only way to get the power and signals out of something that is rotating. Using a clamp to attach it to the base and a 8mm hub to attach the sprocket and angle bracket. The chain is plastic/nylon comes in 1ft lengths all loose links. Doesn't take long to put together and its very adjustable. Which I need because I'm measurement challenged and would probably end up buying several belts before I got things right. With this I can take out or add a link and I have some adjustment by moving the motor around the center mast. No need to run it tight there is practically no load on it at all. Wanted to use a toothed belt but couldn't find pulleys that fit on the .770 bolt pattern of the Actobotics stuff. No need to lube it and its fairly quiet. All the noise is from the motor pretty much so I'm happy with it.










The base is getting pretty crowded. Soon I'll be getting a new one made using a laser cutter vendor. Much thicker thats for sure. The top will go all the way to the back with a cut out for the mast. Longer by half a foot and 2 inches wider.










Changed out the base mounting for a pair of 1" carbon tubes. Nice and rigid now and with the addition of the new thicker base will be nice and solid. New base is going to be black with a slightly tinted top so you can see the workings.
The new motor controller set-up will be here in a week or so. Depends on customs. I have all the ROS packages compiled and ready to go so as soon as those get here I'll be roving.

Griz


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