fig4

Figure 4. Structure of tactile sensor for tri-axis force and pressure direction sense: (A) porous dielectric elastomer-based sensor with four capacitive units for tri-axis force detecting, the arbitrary force can be decoupled into the components of Fx, Fy, and Fz (reproduced with permission^[10]. Copyright 2021, Royal Society of Chemistry); (B) hierarchically patterned e-skin to detect the direction of pressure by analyzing tactile maps from multiple sensing elements (reproduced with permission^[52]. Copyright 2018, The American Association for the Advancement of Science); (C) flexible piezoresistive tactile sensor based on interlocked hemisphere structure for tri-axis force sensing (reproduced with permission^[97]. Copyright 2021, Elsevier).