A self-adaptive alignment strategy for large components based on dynamic compliance center

Abstract

Purpose Aiming at the problems of geometric precision misalignment and unconsidered physical constraints between large components during the measurement-assisted assembly, a self-adaptive alignment strategy based on the dynamic compliance center (DCC) is proposed in this paper, using force information to guide alignment compliantly. Design/methodology/approach First, the self-adaptive alignment process of large components is described, and its geometrical and mechanical characteristics are analyzed based on six-dimensional force/torque (F/T). The setting method of DCC is studied and the areas of DCC are given. Second, the self-adaptive alignment platform of large components driven by the measured six-dimensional F/T is constructed. Based on this platform, the key supporting technologies, including principle of self-adaptive alignment, coordinate transfer, calculation of six-dimensional F/T and alignment process control, are illustrated. Findings Using the presented strategy, the position and orientation of large component is adjusted adaptively responding to measured six-dimensional F/T and the changes of contact states are consistent with the strategy. Through the setting of DCC, alignment process runs smoothly without jamming. Practical implications This strategy is applied to the alignment experiment of large components muff coupling. The experimental results show that the proposed alignment strategy is correct and effective and meets the real-time requirement. Originality/value This paper proposed a novel way to apply force information in large component self-adaptive alignment, and the setting method of DCC was presented to make the alignment process more feasible.

A ball head positioning method based on hybrid force-position control

“…Aiming at the misalignment between ball head and ball socket, we can drive the ball socket of NCL to the corresponding ball head position by measuring the position of the ball head relative to the ball socket with the laser tracker. 12 The main problem of this method is that the measurement accuracy of the laser tracker is not high, 13 and a large lateral force may still be generated during the process of ball positioning. To improve the measurement accuracy of the position of the ball head relative to the ball socket, Liu et al 14 proposed a new method based on visual servo, so that the ball socket can automatically and adaptively approach the ball head.…”