Development of a Tactile Sensor to Measure Tire Friction Coefficients in Arbitrary Directions

In order to develop intelligent tires that measures road surface friction coefficients, the present study proposes a simple tactile sensor that measures threedimensional loads. The sensor is composed of a cantilever called a whisker that is fixed to a base. The base is an elastic plate that has three strain gauges attached to its surface equiangularly around the fixed point of the whisker. The whisker is covered in cylindrical rubber, and the bottom surface is used as a contact. When the sensor touches a surface with the contact and traces it, vertical and horizontal loads are applied to the contact, compressing and bending the whisker so that the base is deformed elastically. Strains induced on the base by this deformation are measured by strain gauges. The study proposes a method obtaining values of vertical load, horizontal load and its direction from measured strains. Accordingly, the proposed sensor measures threedimensional load and obtains the contact surface friction coefficient. In the study, we fabricate a tactile sensor prototype and show its feasibility.