Modeling and control of an adsorbable continuum robot for in situ inspection in aeroengine

Purpose The safety of aeroengine blades is critical to ensure the secure and reliable operation of aviation equipment. However, traditional manual disassembly inspection methods suffer from high labor intensity, low inspection efficiency and quality and high costs. Moreover, the existing inspection robots exhibit poor compliance, low structural stiffness and limited load-bearing capacity, making it difficult to simultaneously meet the high structural stiffness and compliance requirements for in situ blade inspection. Therefore, this paper aims to propose an adsorbable continuum robot for in situ inspection of aeroengine blades to address the contradiction between high compliance and low stiffness for continuum structure. Design/methodology/approach First, an adsorption continuum robot composed of multiple orthogonal layout mortise–tenon joints and vacuum adsorption module was proposed to enhance its structure rigidity and load-bearing capacity. The kinematics model of the robot was established by using the geometric analysis and Euler transformation principles, and the static model was derived by the principle of virtual work. Moreover, an adsorbable unit stiffness parameter was introduced to systematically analyze the range of equivalent stiffness variation under different boundary constraints. Finally, a prototype of the robot was constructed and some motion experiments are carried out to verify the proposed structure and established model. Findings Results showed that the established model can accurately predict the robot’s motion deformation and bending properties under different configuration parameters. The adsorption unit significantly enhanced the robot’s end-effector stiffness and load capacity, with the average load-bearing capacity of the first and second sections increasing by approximately 32.4% and 132.1%, respectively, under adsorption conditions. Furthermore, the average deviation of the robot’s end-effector under adsorption conditions is approximately 6.5 mm, a reduction of about 42% compared to the 11.3 mm deviation without the adsorption, which can effectively validate the correctness of the constructed model and control method. Originality/value To address the trade-off between the high structural stiffness and compliance of the continuum robot for in situ blade inspection in aeroengine, an adsorbable continuum robot has been developed and its kinematics, statics and structural stiffness are analyzed by the experiments. These findings provided a theoretical support and experimental evidence for continuum robot applications in complex confined environments, such as in situ inspection or maintenance of aeroengine blades.