  Typical contact detection is based on the monitoring of a threshold value in
the force and torque signals. The selection of a threshold is challenging for
robots operating in unstructured or highly dynamic environments, such in a
household setting, due to the variability of the characteristics of the objects
that might be encountered. We propose a multimodal contact detection approach
using time and frequency domain features which model the distinctive
characteristics of contact events in the auditory and haptic modalities. In our
approach the monitoring of force and torque thresholds is not necessary as
detection is based on the characteristics of force and torque signals in the
frequency domain together with the impact sound generated by the manipulation
task. We evaluated our approach with a typical glass placing task in a
household setting. Our experimental results show that robust contact detection
(99.94% mean cross-validation accuracy) is possible independent of force/torque
threshold values and suitable of being implemented for operation in highly
dynamic scenarios.
