Modular pipe loader assembly

A method of coordinating movement of first and second shuttle arms along parallel, spaced-apart shuttle paths, the method comprising:

• traversing a first segment of the first shuttle path with the first shuttle arm;
• simultaneously, traversing a corresponding first segment of the second shuttle path with the second shuttle arm;
• measuring a velocity of the first shuttle arm through the first segment of the first shuttle path and a velocity of the second shuttle arm through the corresponding first segment of the second shuttle path during the respective steps of traversing the first segment and the corresponding first segment;
• determining, based on the measured velocities, an adjusted velocity of at least one of the first and second shuttle arms whereby the shuttle arms operate at equivalent velocities when the at least one of the first and second shuttle arms is at the adjusted velocity;
• and
• during a subsequent traverse of the respective first segments, utilizing the adjusted velocity to move the first and second shuttle arms in alignment.