Planar cable-driven parallel robot with fin-like chains for water jet impact acoustic wall inspection

Abstract

The water jet impact acoustic method is the wall inspection method to detect the concrete flaking by analyzing the sound generated by the water hit on the structure. The authors are developing the completely constrained planar CDPR (cable-driven parallel robot) to move and position the device for this method facing the wall. In general, the planar CDPR has relatively low rotational stiffness about the axes on the motion plane, which gives a non-negligible effect on the positioning accuracy of the water jet. Therefore, in this paper, the fin-like chains which mechanically improve the rotational stiffness about the axes on the motion plane are proposed. They are rigid-body chains, which can rotate only around the normal axis of the motion plane. The effect of the mechanism is discussed through the analysis using the stiffness matrix and the stiffness measurement experiments using the prototype.