Investigation into use of piezoelectric sensors in a wheeled robot tire for surface characterization

Abstract

A differential steered, 13.6kg robot was developed as an intelligent tire testing system and was used to investigate the potential of using piezoelectric film sensors in small tube-type pneumatic tires to characterize tire–ground interaction.The robot was instrumented with low-cost piezoelectric film sensors between the inner tube and the tire. An unlaminated and a laminated sensor were placed circumferentially along the tread and an unlaminated sensor was placed along the sidewall. The analog signal passed to the robot via a slip ring. The robot was tested with a controlled power sequence carried out on polished cement, ice, and sand at three power levels, two payload levels, and with two tire sizes.The results suggest that the sensors were capable of detecting normal pressure, deflection, and/or longitudinal strain. Added payload increased signal amplitude for all sensors. On the smaller tires, sensors generally recorded a smaller, wider signal on sand compared to cement, indicating potential to detect contact patch pressure and length. The signals recorded by the unlaminated sensor along the tread of the smaller tire were smaller on ice than cement, indicating possible sensitivity to tractive force. Results were less consistent for the larger tires, possibly due to the large tread pattern.