Development of an estimated force feedback controller based on hertzian contact and ultrasound

In this paper, the design of a novel force controller which combines a neuro-fuzzy algorithm and a new contact ultrasonic probe is proposed. The fuzzy rules emulated network (FREN) has a control algorithm structure based on fuzzy IF-THEN rules. The contact probe is integrated in a Cartesian robotic system with the FREN force control. The contact probe is equipped with a 1 MHz frequency ultrasonic transducer. The probe is constructed by a semi-spherical head and an ultrasonic transducer located at the top of the head. The contact between the probe and the medium is modeled by Hertz theory. The experimental results show that the proposed system exhibits high sensitivity for touching contact, instantaneous contact and reaction force estimation. To test the system, experiments were conducted in elastic and elastic-plastic materials. The results indicate that the proposed system is able to effectively control the contact force.