M100RAK Robotic Arm Kit User Guide

RobotShop Inc. www.RobotShop.com
Important note: During assembly, try to avoid rotating the servo motors manually as it creates
back EMF and added wear on the motors.
Once the assembly is complete, the servos need to be positioned properly. Since there is an
additional 5:1 gearing after the servo, each joint rotation angle is not automatically centered.
Ensuring the joint is centered is currently a manual / visual process. We suggest configuring it
as follows:
Note that the “zero” degree angles for the elbow and wrist would cause the arm to try to reach a
position it is mechanically incapable of reaching. Therefore when configuring the arm, we
suggest using two different angles (such as 90 degrees and 180 degrees) and the associated
servo pulses to develop a linear equation relating the servo pulse to the angle.