My first robot.

raess · November 26, 2017, 12:43am

[size=2][font=Arial]Hi All.
I’m building my first robot. I have basic knowledge of programming and no previous experience with ROS or linux.
I will publish during the construction of the robot.

I’m a week into the construction and learning on the way.

Let’s start by the hardware:[/font][/size]
][size=2][font=Arial]Jetson TX2[/font][/size]/:m]
][size=2][font=Arial]Sweep Scanner[/font][/size]/:m]
][size=2][font=Arial]Roboclaw ST 2X45A[/font][/size]/:m]
][size=2][font=Arial]Realsense ZR300[/font][/size]/:m]
][size=2][font=Arial]2x DC Planetary Geared Motor 24 Volt with Hall IC 30-33 RPM 8mm[/font][/size]/:m]
][size=2][font=Arial]2x Vapex Li-Po Battery 6S 22.2V 4000mAh 25C XT60-Contact[/font][/size]/:m]
][size=2][font=Arial]Reach RTK kit.[/font][/size]/:m]
][size=2][font=Arial]USB 3.0 hub 7-way power supply.[/font][/size]/:m]
][size=2][font=Arial]SparkFun 9DoF Razor IMU[/font][/size]/:m]
][size=2][font=Arial]SONY Dualshock 4.[/font][/size]/:m][size=2][font=Arial]I have not really decided which wheels to use. so I’ll start with some temporary D175mm. The chassis will also be a temporary chassis until all parts and the robots works as expected.

The Jetson

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[size=2][font=Arial][/font][/size]
[size=2][font=Arial]ZR300 and Sweep[/font][/size]

[font=Arial][/font][size=2][font=Arial]First connection of motors and motor controller, did not work as expected. Had trouble getting encoders to work due to excessive noise.

Second connection of motors and motor controller with pull up resistors, encoders now work (All settings checked via Ion Motion Control). I will make this install a bit nicer

[/font][/size][size=2][font=Arial]Getting Roboclaw to run on the Jetson @ubuntu 16.04 via USB. The Roboclaw is connected as ttyACM. I needed to build kernel and add the ttyACM module. I also added the Roboclaw in[/font][/size]
[size=2][font=Arial][highlight=#ffffff]99-usb-serial.rules so it always can be found as /dev/roboclaw.[/highlight]
[highlight=#ffffff]Then I paired the DS4 over BT and installed package joy_teleop and it all worked

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[font=Arial][size=2]A very temporary chassis & wheels for a test drive test.[/size][/font]

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I have started to make a [font=Arial][size=2]temporary URDF, to use for the [/size][/font][font=Arial][size=2]temporary[/size][/font][font=Arial][size=2] chassis. I will not spend a lot of time on the design before i know the exact d[/size][/font]imensions[font=Arial][size=2] for the build. [/size][/font]
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That’s my progress this week.
I welcome your tips.
To be continued.

bdaouas · November 27, 2017, 9:47pm

Hi Raess,

Wow, really nice project you started working on https://www.robotshop.com/forum/images/smilies/icon_smile.gif Thank you for posting it on RobotShop’s forum.
Are you planning to use the robot for object/face recognition using the Realsense ZR300 ?
You can take a look on our Wheeled & Tracked Robots category for a nice chassis for your robot.
We would certainly want to hear more about your project. Please, don’t hesitate to post your progress here.

raess · November 27, 2017, 10:08pm

[font=Arial]Thanks bdaouas,
It’s actually going to be a robot lawnmower. Using the ZR300 for mapping and object recognition.
Thanks for the tips for the chassis. but I will make a custom base plate with CNC which is more suited to my final robot.

Update.
Today I have been working on the IMU. I am using the Razor 9dof m0, but immediately I encountered problems.
On my mac everything seems to work fine.

screen /dev/cu.usbmodem11 115200 outputs the serial read nice.

On both my linux machines ubuntu 16.04 & ubuntu 14.04

screen /dev/ttyACM0 115200
[/code] outputs nothing. it just waits.

I have tried to add [code]
usermod -a -G dailout rf
[/code] [size=2][highlight=#eff0f1]and [/highlight][/size][code]
chmod 666 /dev/ttyACM0

any suggestions on how to solve this?[/font]

raess · November 28, 2017, 10:17am

Got the IMU working. Problem is that is does not autostart when plugged in to the Jetson. Does anyone know how to start serial output without having to press space?

bdaouas · November 28, 2017, 3:39pm

Hi Raess,

Seeing the default firmware loaded on the 9 Degrees of Freedom - Razor M0 IMU, the “Space” key seems to pause/resume the serial port printing.
Maybe you can modify the firmware code and upload it to your Razor Board

raess · November 28, 2017, 8:14pm

Thanks bdaouas,
I solved it. all good

raess · November 29, 2017, 10:02am

Last night I worked on power harness, did some basic soldering.

Also received my Reach RTK.
Did a quick test run (indoors) so the satellite reception was not that good. But it seemed to work fine.

Rosnode is running.

Continue to experimenting with this later

raess · December 9, 2017, 5:42am

@bdaouas

What key hub fits this wheels:
robotshop.com/eu/en/8in-aluminum-omni-wheel.html

And why do you only sell the left wheel on this:
robotshop.com/eu/en/203mm-steel-mecanum-wheel-rubber-rollers-left.html

Thanks!

raess · December 10, 2017, 7:28pm

I decided to do a better temporary chassis. Since the old only wood was to unstable.

bdaouas · December 11, 2017, 3:19pm

Hi Raess,

]You can use the 500 Key Hub with the 8" Aluminum Omni Wheel. You will also need the Hardware Kit 7 : Hub Mount to 8" Aluminum Omni Wheel (screws and nuts) to mount the hub to the wheel. We just entered this mounting kit to our catalog and will be soon available on the website under the product code : RB-And-245./:m]
]The Right 203mm Steel Mecanum Wheel has been discontinued. The 203mm Steel Mecanum Wheel w/ Rubber Rollers (Left) will also be discontinued. We do offer the 203mm Steel Mecanum Wheel w/ Rubber Rollers (2xLeft, 2xRight) which is a set of 4 wheels or the 152mm Mecanum Wheel Set (2x Left, 2x Right)/:m]

raess · February 9, 2018, 6:35am

So the project is mowing forward. I have just made the first concept model and is now printing it in real size around 700mm long.

bdaouas · February 12, 2018, 2:09pm

Hi Raess,

Very nice design. Well done https://www.robotshop.com/forum/images/smilies/icon_smile.gif
Will you 3D print the shell for a prototype ?

raess · February 21, 2018, 3:36pm

Thanks Bdaouas! Yes Prototype will be 3D-printed in my Raise3D N2+.
So after printing some parts for Valify I realized, first of all, it looked like any lawnmower out there. So I had to go back to the drawing board and start from scratch. I wanted a unique look that looked fresh and futuristic. I also took some experience from the previous one and made improvements. This is Valify V2.

Bdaouas I am looking for 3 small powerfull brushed motors with 3000-5000rpm for the cutting blades. Do you have any suggestions?

My build blog is found here: valify.se

raess · February 22, 2018, 2:39pm

Btw:If somebody wants it, all parts are available on thingiverse
This thing is still a Work in Progress. Files, instructions, and other stuff might change!

bdaouas · February 22, 2018, 3:24pm

Here is a link to our Brushed DC Motors category .
Is there a reason why you have chosen to use a brushed motor as mowing motor instead of brusheless ?
We have tested a brushed dc motor (the RB-Ban-228) in our Robokut project (that you can find here in LMR) and the motor got really hot very fast when mowing grass and it wasn’t efficient for cutting.
We have replaced it with a brusheless motor similar to the Outrunner Sunshine Brushless Rotor Motor 880KV 16.8A with nylon trimmer cord which worked quite nicely.

rickhendrix · March 1, 2018, 3:33pm

Good work

raess · March 1, 2018, 8:27pm

[size=2]@bdaouas No specfic reason, Only that I use to work with brushed. But sure I give the brushless motors and test. I was looking at the recommended motor and saw that you recommended a motor with [highlight=#ffffff][font=Helvetica Neue, Helvetica, Arial, sans-serif]KV(RPM/V): 880. That´s quite low?[/font][/highlight]
[highlight=#ffffff][font=Helvetica Neue, Helvetica, Arial, sans-serif][/font][/highlight]Thanks @Rickhendrix.

Update on the build:
[font=Arial, Helvetica, sans-serif][highlight=#ffffff]So First Part For The Robot Is Printed! I use PrimaSelect PETG @240C.[/highlight][/font]
valify.se/2018/03/01/success-first-part-for-the-robot-is-printed/[/size]

here is some pictures:

raess · March 7, 2018, 10:10am

[size=2][font=Arial]Part 4 has completed 3D printing and the 5 part is printing now.
When The 5 part is ready I will have a good overview how to bottom chassis will look like.

I also going to change from the robot drive system, I was first thinking off using [highlight=#ffffff]DC Brushed Planetary Geared Motor but instead I will go for [/highlight][highlight=#ffffff]6355 Sensored Brushless (BLDC) motors 190kv running on VESC and belt drive. [/highlight]
[highlight=#ffffff]Some first sketches on the new drive [/highlight]system:[/font][/size]