The fashion of building world saving open source robot arms is in full swing. This arm however has a pretty specific mission and it seems to be built properly to do it. It is designed to hold a pair of tool heads vertically. It is a SCARA style arm which means it dispenses with the complicated wrist and shoulder actuators but has fewer degrees of freedom. . However compared to a classic gantry style CNC this has the benefit of being smaller, but has the disadvantage of being far less rigid. I wish them luck and hope to see another entrant into the world of open source.
There have been two more robotic arms on Kickstarter in the last month or so. The Niryo it appears has been successful, as was the Haddington Dynamics Kickstarter. Is this the new 3D printing for Kickstarter?
uFactory, is releasing their 3rd generation arm, the “Swift” which looks to be a nice improvement on their previous arm the uArm metal (Note: I own a uArm Metal and reviewed it here). The uArm was traditionally a servo based arm, which, if you read this blog, know that I am not the biggest fan of. However, this time around they are delivering a “Pro” version which has both steppers and encoders. This can provide a series of benefits:
- Improved accuracy, linearity and repeatability even when bumped or overloaded
- The ability to manage acceleration, deceleration
- Allows a training mode where the arm can record the position you put it in (this is done with the encoders, not the steppers)
In addition it looks like they have added a few more nice capabilities to the uArm including:
- Improved Software (the software in the first version was already pretty nice.)
- Different end-effectors including a claw and a laser marking head.
I wish them luck, the product looks like a winner and has already exceeded the funding goals. The link the the Indiegogo site is here.
Another open source robot arm has cropped up on Kickstarter, It seems to have 6 DoF which is nice. Surprisingly it uses brushless DC motors and Hypocycloidal gearboxes that they claim are backdriveable. This is a serious step up from the hobby servos many arms use but there are lots of tradeoffs with hypocycloids which need to be overcome. The motion looks a bit jerky right now as well, so I suspect some more work needs to be done either on software or hardware. All said though, the ambitiousness of the design and price point has me intrigued.
Bart Dring, whom I have followed for a while, in fact ever since I built an ordbot, one of his 3D printer designs. Has started working on a Robot Arm and did what I thought to be nigh impossible, 3D Printing a harmonic drive.
Hackaday.io has attracted another nice robotic arm project to it’s site. This is arm is a very nice, open source design that makes clever use of a differential to combine 2 degrees of motion into a single joint. I also appreciate that he was good enough to go through the inverse kinematic model that defines this arm. Inverse kinematics is a mathmatical method to figure out arm angles required for the end effector (the gripper in this case) to be in a certain location. More at this link
I have added some long overdue security enhancements to robotarm.org. First is that the site now supports HTTPS, for those that dont know, this provides for the authentication and encryption of the packets that travel between your browser and our servers to prevent an observer in the middle from seeing your traffic. For those who are curious, I am using a free certificate from Let’s Encrypt. Second is that I have added a security question for new sign-ins is likely most cannot be answered without research. While I expect this second one to slow down adoption of this community, ultimately I think those who do choose to sign up will see less spam and enjoy the community more. If you have any questions, please put them in the comments below.
A very cool drawbot. I am typically not a fan of servo based robots, however this appears to be dynamixels or something like that rather than hobby servos. Overall the results are excellent.
It has been a little while since I have made any progress, but with the summer’s vacations and other activities out of the way, I have a chance to buckle down and get some stuff done. This is actually the first time I have gotten motion with the arm with the new electronics. All seems to be working fine, except for a few issues with multistepper (Arduino Library). Next is getting the pen going.
Note – you will notice the steppers are making a bit too much noise, I just haven’t set them up properly, that will change soon.
The 2 degree of freedom arm end effector is nearly complete. Here it is controlling a pen up/down motion. The current design depends on gravity to bring the pen down which is probably ideal for felt tip pens and the like. It uses a micro servo to drive the pen upward. The design is 3D Printed and the files will be uploaded to Github shortly. More coming soon…