No abstract

Purpose This paper aims to present an optimization algorithm combined with the impedance control strategy to optimize the robotic dual peg-in-hole assembly task, and to reduce the assembly time and smooth the contact forces during assembly process with a small number of experiments. Design/methodology/approach Support vector regression is used to predict the fitness of genes in evolutionary algorithm, which can reduce the number of real-world experiments. The control parameters of the impedance control strategy are defined as genes, and the assembly time is defined as the fitness of genes to evaluate the performance of the selected parameters. Findings The learning-based evolutionary algorithm is proposed to optimize the dual peg-in-hole assembly process only requiring little prior knowledge instead of modeling for the complex contact states. A virtual simulation and real-world experiments are implemented to demonstrate the effectiveness of the proposed algorithm. Practical implications The proposed algorithm is quite useful for the real-world industrial applications, especially the scenarios only allowing a small number of trials. Originality/value The paper provides a new solution for applying optimization techniques in real-world tasks. The learning component can solve the data efficiency of the model-free optimization algorithms.

No abstract

Peg-in-hole is one of the most frequent mating features between parts, where the large friction resistance and poor contact situations result in the failure of part mating. To address this problem, this paper proposes a screw insertion method in peg-in-hole assembly for axial friction reduction. First, the effect of screw motion on axial friction reduction is analyzed with point contact and face contact. Second, the screw insertion method in clearance-fit peg-in-hole assembly with point contact is discussed; this method works better than the conventional linear insertion method for jamming prevention; the reciprocate screw insertion strategy is also investigated to reduce the influence of axis offset on screw insertion. Third, the screw insertion method in interference-fit peg-in-hole assembly with face contact is discussed. Finally, axial friction reduction is validated with experiments of point contact with screw motion and experiments of screw insertion in clearance-fit and interference-fit peg-in-hole assembly.

No abstract

No abstract

No abstract

No abstract