Fabrication: A step-by-step guide (part 3)

Final assembly

Once all the parts of the manipulator are fabricated, we can start the final assembly of the robot. The first step is to attach the base platform to the bottom of the plank in the base frame. As explained before, long bolts of Ø4mm and nuts are used to fix the platform.

The next step is to connect the second section to the first one.  30mm long Ø2.5mm bolts are used to attach the two parts of the middle rigid platform; this was done with the objective of having a small gap between the two parts of the middle platform, so that the tubes that supply the air to the second set of pneumatic actuators could have some room to bend.

With both sections in place, we can start putting the cables through their dedicated holes. There are six cables in total, three of them go from the base to the middle platform, while the other three go from the base to the top platform. The cables are actuated by servos placed on top of the base cover. Special care is needed while putting the servos in place, to make sure that the pulleys attached to the servos are aligned with the cable holes at the base platform. Nuts were tied up at the end of each cable so that the cables can apply forces to the platforms.

          

After every part is in its place, the robot looks like this: