Analytic integration of tolerances in designing precision interfaces for modular robotics

Modularity in robot structures allows for achieving various system configurations using a limited number of interconnecting modules. However, the requirement for system calibrations following reconfigurations must be diminished through the achievement of high accuracy and stiffness in module connections. The capability to design high performance connection interfaces that can guarantee the needed level of system accuracy is the key factor for the success of modular robotics. In this research, a simple analytical method is pursued, which relates the major connection interface design parameters such as stiffness, geometry, and manufacturing tolerances to the final relative position and orientation of the module connections. The primary purpose of this method is to efficiently obtain an initial set of design parameter values for connection interfaces considering both the allocated tolerances and the connection accuracy to be achieved based on the required accuracy level of the overall system. The obtained method is applied to design a precision module connection interface for a specific system, following an assessment on the desirable level of connection accuracy and stiffness. Stochastic accuracy analyses are performed on a linear connection model through matrix operations for the allocated manufacturing tolerances.