Analysis and development of self-reconfigurable open kinematic machinery systems

This paper presents the analysis and development of the model, dynamics and control of new self-reconfigurable machinery systems. These machinery systems combine as many properties of different open kinematic structures as possible and can be used for a variety of applications. The kinematic design parameters, i.e., their Denavit-Hartenberg (D-H) parameters, can be modified to satisfy any configuration required to meet a specific task. By varying the joint twist angle parameter (configuration parameter), the presented model is reconfigurable to any desired open kinematic structure, such as Fanuc, ABB and SCARA robotic systems. The joint angle and the offset distance of the D-H parameters are also modeled as variable parameters (reconfigurable joint). The resulting self-reconfigurable machinery system hence encompasses different kinematic structures and has a reconfigurable joint to accommodate any required application. Using the Newton-Euler (N-E) recursive approach, the dynamic parameters of a reconfigurable joint are calculated and presented. A nonlinear control law is developed for a general reconfigurable joint using Lyapunov second method achieving asymptotic stability and the required performance objectives. Automatic model generation of a 3-DOF reconfigurable machinery system is constructed and demonstrated as a case study which covers all possible open kinematic structures. This research is intended to serve as a foundation for future studies in reconfigurable control systems.