Lately I've been thinking about 6 axis robots and noticed that all examples that I've seen on the internet use the same configuration of axes:
Vertical axis waist (1), horizontal axis shoulder (2) and then the axes are perpendicular (3), parallel (4), perpendicular (5) and parallel (6) with the previous link.
This means at least three different types of joints, one for waist (1), one perpendicular (2, 3 and 5) and one parallel (4 and 6). I was wondering if comparable range of motion can be achieved by having only one type of joint in addition to waist.
I thought that having only axes perpendicular to previous segments (like 2 and 3 in the picture), but instead of consecutive pairs of axes being parallel to each other, have them twisted by some fixed angle (45 degrees?) relative to each other.
Would an idea like this work? Would it have any significant disadvantages? Is there some general method to visualise what positions can be reached with a given configuration of axes?