Comparison of Inverse Kinematics Algorithms for Digital Twin Industry 4.0 Applications

This paper presents two Inverse Kinematics (IK) algorithms that are used for digital twin Augmented Reality (AR) applications. The first algorithm is a simple Inverse Kinematics (IK) Unity code that considers up to 9 points on the human body to model the motion. The second algorithm is the BIO IK that can consider up to 38 points. The performance of the algorithms is compared with data obtained by a Motion Capture (MoCap) measurement system. The metric of accuracy was used to quantify the performance evaluation and was modeled as the error of the position of the modeled joints of a human avatar with those measured by the MoCap system. It is observed that the obtained accuracy of the position increases with the number of points that is considered by the IK algorithm. For the purpose of this investigation, a MoCap system based on 13 cameras and 38 markers on the human body was used to measure the location of the joints of a human operator performing specific motions. The motion of lifting was the epicenter of the investigation that causes the larger amount of accidents in typical manufacturing facilities. The application of this research falls within the concepts of Digital Twin (DT) in Industry 4.0 scenarios.