Design of a Multi-lobed Flexible Multidimensional Force Sensor Inspired by Petal Structures

Multidimensional flexible sensing units serve as key components for realizing tactile perception. However, existing technologies mainly focus on uniaxial normal pressure detection and have limitations in directional sensing of tangential forces. Inspired by petal structures, here we propose a multi-dimensional force flexible sensor with a multi-lobed symmetric electrode structure. Through Finite Element Method (FEM) analysis of the electrode structure, the design demonstrates improved sensitivity characteristics to both normal and tangential displacement. An integrated experimental-FEM model established quantitative relationships between applied forces and capacitive responses, achieving prediction of normal force magnitude, tangential force magnitude, and tangential direction. Validation via a dual-mode force-controlled testbed demonstrated multidimensional sensing capabilities with: 5.7% normal force error, 5.5° tangential directional error, and 0.14 N tangential magnitude error. A preload-dependent correction factor was further developed to compensate for detection deviations under varying compression states. This work provides technical support for multidimensional force tactile perception.