Development of a Robotic Palpation System and Evaluation of the Burden to an Operator in the Palpation

In this paper, a laparoscopic surgical robot equipped with a new palpation system which can identify the location of an imitation tumor under use of a trocar was developed based on our previous studies. In robotic surgery, when palpation is performed under use of the trocar, it is difficult to realize force or tactile sense of the touched object because the forceps is affected by contact with the trocar. Therefore, cancelation of an influence of the trocar on the forceps was attempted by using the neural network which was previously trained the influence of the trocar on the forceps. In order to verify an effectiveness of the developed palpation system, location identification experiments were carried out for both longitudinal and lateral directions palpation, in which identification of location of the imitation tumor was attempted for 4 kinds of sample with each different tumor location, respectively. The results showed the effectiveness of the neural network, and identification error of location of the imitation tumor was less than 1mm. In addition, the physical burden added to the operator while performing palpation work using the developed palpation system was evaluated by comparison of the energy expenditure obtained through the analysis of expired gas under the following conditions; (a) only force feedback was conducted, (b) only tactile feedback was conducted, and (c) both force and tactile feedbacks were conducted. The result showed that the physical burden to the operator under the condition (c) was smallest.