OpenCV Robotic Hand

The fingers for the robotic hand are hinge joints with a single degree of freedom. Elastic bands are used to tension the fingers, while fishing lines attached to servo motors are used to close the fingers. Thus, fingers are designed to have fishing lines and elastic bands running through them. The fingers and the hand are 3D printed with Prusa printers for accuracy. PLA was chosen as the material as it was the easiest to manufacture while having enough structural integrity to support the forces involved. 

Several designs were manufactured and tested to find the optimal design that ensures that the system works effectively for prolonged periods. A major change made from previous to current versions was not keeping the joints between the phalanges of the fingers fixed with pins. Although having pins in places of the hinge joints allowed the fingers to have fixed movements, I encountered many problems with it. Firstly, the nuts often come loose due to vibrations and constant movement. Even with washers in place, the phalanges often came loose after extended use and testing. Secondly, I found it unnecessary, as the tension from the elastic bands was strong enough to keep the phalanges in place. Having the elastic band loop around the fingers generated enough stability for a relatively fixed movement. Finally, having bolts tighten the joints in which the phalanges move meant that there was greater friction that needed to be overcome for the fingers to close. This meant the micro servos previously planned for use did not generate enough torque to close the fingers.