Serial manipulator functional calibration for in vitro biomechanical testing.

Area of Science:

• Robotics
• Biomechanics
• Mechanical Engineering

Background:

• Serial manipulators are crucial for biomechanical testing due to their precision.
• Commercial manipulators often lack global positional accuracy because of manufacturing and assembly imperfections.
• Existing calibration methods primarily address static errors under constant loads, neglecting dynamic conditions.

Purpose of the Study:

• To develop a novel functional calibration procedure for serial manipulators.
• To address the global accuracy of manipulators during continuous motion with time-varying external loads.
• To improve the precision of robotic systems for human joint biomechanical testing.

Main Methods:

• Developed a novel functional calibration procedure for static and dynamic calibration.
• Utilized optimization techniques to populate a 34-parameter model.
• Applied the method to a Mitsubishi PA10-6CE serial manipulator as a case study.

Main Results:

• The functional calibration significantly reduced mean/peak static position errors to 0.368/0.67 mm.
• Mean/peak dynamic position errors were reduced to 0.353/0.81 mm.
• The calibration accounted for both geometric and non-geometric parameters under external loading.

Conclusions:

• The developed functional calibration procedure effectively enhances the global accuracy of serial manipulators.
• This method is essential for accurate biomechanical testing of human joints under dynamic and externally loaded conditions.
• The 34-parameter model successfully minimized both static and dynamic position errors.