Valify V2 Robot Lawnmower

Description

This project aims to build an "smart" robot lawnmower using open technology.

Features
-differential drive using two sensored brushless (BLDC) motors
-driven by two open source speed controllers (VESC)
-uses Field Oriented Control mode to have near silent operation
-no perimeter wire (main goal)
-3D-mapping with camera and lidar
-precise location using RTK
-9DOF (9-axis motion tracking module)
-regenerative braking
-traction control
-solar cells (only as a extra bonus power supply)
-path planning, different cutting styles (diagonal, vertical and more)
-self-adjusting cutting height

Details

Valify Robotic lawnmower. A hobby project created with a great interest in technology.

Valify robot next to his brother Robomow RC312

A robotic lawn mower is an autonomous robot used to cut lawn grass. A typical robotic lawn mower requires the user to set up a perimeter wire around the lawn that defines the area to be mowed.

The robot uses this wire to locate the boundary of the area to be trimmed and in some cases to locate a recharging dock. So this project was born in my mind when I bought my first house and invested in a Robomow RC312 for the garden. Running it for almost 2-years I
encountered lot of problems with the existing “brains” and basic
functionality of the “robot”. So I started thinking of ways to improve this. After a some research. It seemed that technology existed to build a really smart robot that could make its own decision and adapt itself to the garden. Looking up different solutions on how to solve this, I found the RTK technology was very interesting. But a bottle neck existed, the GPS signal needed to be quite strong to receive centimeter accuracy (would not work well with trees and other items that cover the satellite reception).

Emlid Reach RTK test indoors (20mm scale)

Combining the RTK with Lidar sensors, Intel® RealSense™ 3D Camera and the odometry coming from high-resolution rotary position sensors on the motors would maybe give the needed accuracy for autonomous lawnmower that could 3D map the garden and make its own decision based on the environment with centimeter accuracy.

AS5048S rotary position sensor — The absolute magnet angular position is measured with a resolution of 14 bit = 16384 positions per revolution and it is provided as a digital value on the serial interface (SPI).

The goal is to have the ability to create virtual boundaries around objects and the flexibility of adapting to environment changes without today's hazzle with perimeter wires.

I believe that in the next few years all new mowers will have the ability to navigate without the perimeter wire. A transition to actual autonomous robots will happen and this is my development project entering the world of robotics.

Files

BOM_(not completed).xlsx

Working on a BOM

sheet - 11.59 kB - 04/10/2018 at 12:51

Download

Components

1 × Jetson TX2 Development Kit

1 × Scanse Sweep

6 × Bearing radial Reely F688ZZ 5 mm

6 × Steel Intermediate tray 8 mm 14 mm 0.2 mm

2 × Clamp ring Outer diameter: 18 mm Thickness: 6 mm

Project Logs

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2018-05-16

Robin Fröjd • 05/17/2018 at 07:37 • 0 comments

The URDF is very time consuming but its coming along nicely. I have added all joints and are now working on to make them work as in reality.
The wheels are working great and the visualization in RVIZ presents the reality very well.

I have also started to work with the IMU joint and the ability to visualize the rotation of the robot (pitch, roll,yaw). To got this working I am using robot_localization pkg (sensor_fusion) Here I am fusing Odom and IMU to odometry/filtered. The visualization is still not very good for the IMU and will need some more love

2018-05-14

Robin Fröjd • 05/16/2018 at 05:45 • 0 comments

Tonight I have begun building the robot's URDF for better and nicer visualization in RVIZ when driving around. I also hooked up the 9DOF to test and confirm its functionally .I am using the (SparkFun 9DoF Razor IMU M0 - SEN-14001) and it was not easy to get it to work over ROS, but finally it did ;-)

The URDF will be an exact copy of the real robot and I will mostly use combined STL´S files as meshes for the URDF.

2018-05-13
Robin Fröjd • 05/15/2018 at 12:09 • 1 comment

Today I did the first test drive! Yey! One pulley still makes annoying sounds.
2018-05-09
Robin Fröjd • 05/09/2018 at 20:16 • 0 comments

Testing the drive system. I need to remake the pulleys because they are slipping. Otherwise everything works fine!

Small test video

2018-05-07

Robin Fröjd • 05/07/2018 at 21:07 • 0 comments

So the last days I have been busy. All parts for the drive system was completed and tonight I finished the first test assembly of the drive system. Its a lot of parts for this part of the project and a lot of things need to be correct in order for a nice run. It took a bit of time to get it right and it was a lot of tinkering.

A quick video spinning the wheels:

2018-04-30
Robin Fröjd • 04/30/2018 at 20:44 • 0 comments

Project update:
Drive system assembly test. Everything fits perfectly. Some welding left and we are good to go :-)
2018-04-26
Robin Fröjd • 04/27/2018 at 06:46 • 0 comments

Left wheel arch part 1/2 completed late last night!
3D printing wheel arch for robot
Test assembly. The covers fits nicely! Not so many parts left to print! I need to order more filament!

3d printed wheel arch test assembly
3d printed wheel arch test assembly
2018-04-25
Robin Fröjd • 04/25/2018 at 19:10 • 0 comments

olala, Today all parts for the drive system is completed.
Some parts will be welded together and then the assembly will begin next week!
I have to admit that I am a little excited :-)
Drive system components CNC Milled
Drive system components CNC Milled
2018-04-24
Robin Fröjd • 04/24/2018 at 09:27 • 0 comments

First big body cover printed. The part came out great. Running PrimaSelect PETG Solidwhite at 240C. This print was printed with 0.6mm nozzle instead of the original 0.4mm. layers looks nice and even! This part was printed at 2 shells at 10% infill and print time landed on around 15h.
First big body cover 3D printed.
First big body cover 3D printed.

The motor brackets are ready and just some minor things left to be CNC milled. Then finally I can assemble the drive system

CNC Milling motor brackets
a pair of CNC milled motor brackets
2018-04-21
Robin Fröjd • 04/21/2018 at 10:37 • 0 comments

3D printing New front nose, ready in 1h. Hopefully everything fits perfect!