中国科学院自动化研究所机构知识库

This paper proposes an efficient strategy for the insertion of the partially flexible object in precision assembly. The partially flexible object refers to the component with unevenly distributed flexibilities: coupling rigidity and flexibility. This paper focuses on the insertion of one class of partially flexible objects: rigid shapes connected by a compliant mechanism. We first analyze the horizontal compliance of the compliant mechanism and build a model to relate its state and force. The insertion is separated into two stages according to the insertion type. The first stage is a compliant insertion and we estimate the insertion direction based on the built model, horizontally compensate resorting to the horizontal compliance and the updated direction, and efficiently plan the vertical insertion in an aggressive strategy regarding the uncertainties caused by the compliant mechanism and predicting the future insertion. The second stage is a hybrid insertion with both rigid and compliant gripping and its features include that the object states are not precisely measurable and the motion of a part of the object is not directly controllable. To solve it, we qualitatively and quantitatively analyze all possible configurations and, taking advantage of the insertion property, conclude one insertion posture based on which a control strategy is proposed. Additionally, a conservative insertion strategy is planned resorting to the past execution performance and the current state evaluation. Experiments are carried out to demonstrate the validation of the proposed method. Note to Practitioners-This paper was motivated by the problem of inserting partially flexible objects in precision assembly, but it also applies to other components with unevenly distributed flexibilities. This approach has benefits in terms of assembling rigid-compliant-rigid sets of the objects and modeling the behavior of many similar objects. The following key steps are mentioned to apply the proposed method. The practitioners need to first compute the insertion compliance based on the model that is built in this paper to relate the deformation and force. The determination of the object configuration in hybrid insertion is then demanded considering the system compliance. The final steps are to obtain the object states according to the force output and efficiently plan the insertion depths considering the past performance, the current evaluation, and the future prediction. In future research, we will address the simultaneous assembly of multiple partially flexible objects.