Interesting Scara Robot Design.
Below is a video and the Url of an interesting scara robot design. What I like about it is the arm end is really low mass because all the motors are near the shoulder joint. Scara robots often have a linear actuator on the arm end, but he opted to raise and lower the entire arm instead. Here the blog url: http://www.heliumfrog.com/hf06robot/hf06blog.html
Comments
Yes and the movement is super smooth because he used steppers over servos. He was also nice enough to publish his code on his website. The IK for a scara robot looks much simpler than a revolute robot arm, but stepper motors are more complicated than servos because you need control both their position and velocity.
The one part of his design I disagree with is that he gave up on threaded rod for the Z axis too easily. He was using hardware store threaded rod which has too many threads per inch and results in slow movement. However, acme threaded rod in a one to three foot lengths isn't all that expensive, nor are the anti-backlash nuts it uses. The advantage of acme threads is they are faster than normal threaded rod, and unlike a belt the robot won't fall if you turn off the Z axis motor.