This robotic arm has 4 Degrees of Freedom (motors): one to turn, one to move vertically, one to move horizontally and the last for the gripper. Its parallel linkages allow the tool to remain always oriented downwards.
The robot uses RC servos instead of NXT motors, because they allow more precise movement control, ease of assembly, smaller dimensions. The servos are driven using MINDSENSORS NXTservo interface. The shape is inspired to the real FANUC manipulator arms used in the factories for goods handling.
The end effector can be easily replaced.
In the picture at right, you can see the custom mount for the microservo. To make the microservo LEGO-compatible, I glued a but Pin Joiner and a 1×3 liftarm to the servo case, and a Technic bush to the horn.
I modeled the missing LDRAW parts for the Mindsensors NXT servo mounts, plus the micro servo custom mount that I invented. As you can see in the rendering, the servos can be assigned different colors, in order to distinguish them in your model.
To install the new RC servo parts, extract the archive into your LDRAW root folder. You can find the other Mindsensors servo parts in this Philo’s webpage.