Multi-axis force measurement based on vision-based fluid-type hemispherical tactile sensor

We propose a new method for the measurement of multi-axis contact force by using vision-based fluid-type tactile sensor. The proposed sensor can also estimate the multimodal tactile information such as the slippage, the shape, the contact region and the location of the contacted object. Multi-axis contact force is transformed from the elastic membrane tensional force on the touchpad surface, and the touchpad inner pressure measured by the pressure transducer. We obtain the tensional force by solving the equilibrium equations developed in each compartmentalized segment of the membrane, based on the shape information of the touchpad. The proposed method is general and can be applied to various touchpad contact situations. The usefulness of the proposed method is demonstrated through experimental results.