Kinematics and validation of an adsorbable continuum robot for aeroengine blaes <i>in situ</i> inspection

Purpose This paper aims to propose an adsorbable continuum robot for aeroengine blade inspection to improve its structural stiffness and load capacity. Design/methodology/approach A continuum robot composed of a cross-shaped, staggered, mortise-tenon flexible joint and an adsorption unit was proposed, and the kinematics model of the robot was established by Denavit-Hartenberg method to analyze the mapping relationship between its bending characteristic and structural parameters. Moreover, a robotic shape-sensing method based on multiple Bézier curves and inertial measurement unit was proposed to detect its bending shape. The prototype of the adsorbable continuum robot was built to verify the correctness and effectiveness of the proposed adsorbable continuum structure and the established model. Findings Results of the experiments show that the proposed adsorbable continuum robot can achieve flexible deformation within the bending angle range of 90°; maximum detachment forces of the robot under vertical adsorption and horizontal adsorption are 4.42 and 3.4 N, respectively. The reconstructed bending shape of the robot closely matched the actual shape. Originality/value The adsorbable continuum structure, kinematics model and shape-sensing method discussed in this paper can achieve precise control and improve the structural stiffness of the robot, which can address the contradiction between the high flexibility and low stiffness of the ultra-redundant continuum robot structure.