Nonlinear flexure coupling elements for precision control of multibody systems

Conventional multibody systems used in robotics and automated machinery contain bearing components that exhibit complex and uncertain tribological characteristics. These limit fundamentally the precision of the automated motion and also cause wear. Replacing traditional bearing joints with flexure couplings eliminates these tribological effects, together with wear, reducing necessary system maintenance and offering a potential for increased motion precision. A flexure-coupled multibody system is considered and a novel general solution technique is presented. Derivation of a large deflection flexure coupling model is provided and subsequently validated using an experimental facility. A focused study of a unique double flexure coupling-rigid body system is given; the formulated nonlinear mathematical model can be utilised for feedforward control. Equivalent control is also applied to a corresponding system with traditional bearing joints. The feasibility of replacing bearing joints by flexure couplings is demonstrated in terms of accurate large displacement control and reduction of high frequency disturbances.