A New Cable-Driven Model for Under-Actuated Force–Torque Sensitive Mechanisms

Abstract

Force–torque sensors are used in many and different domains (i.e., space, medicine, biology, etc.). Design solutions of force–torque sensors can be conceived by using many types of connections or components; however, there are only a few sensors designed using cable-driven systems. This could be related to many reasons, one of which being that cables are able only to pull and not push. In this paper, a new cable-driven model for under-actuated force–torque sensing mechanisms is proposed, simulated, and tested, underlining the novelty of using cables for force–torque sensing. Analytical formulations, simulations, and physical implementations are presented in this paper. Results confirm that the new proposed model can be used for force–torque sensing mechanisms in micro- and macro- applications where under-actuation is a fundamental requirement, as in robotic surgery. The proposed model and mechanism can be used in the design of sensors and actuators. The innovative model is validated with two different test benches, opening new challenges in the design and development of under-actuated force–torque transducers.

Cable-Driven Mechanism Models for Sensitive and Actuated Minimally Invasive Robotic Instruments

“…Our past works, ref. [5] and ref. [12], focused on this new research direction [13][14][15][16][17][18][19].…”

“…On the contrary, in robot-assisted surgery, only a few small incisions on the patient's body are performed to insert the tools in the body. This approach of robotic surgery is called minimally invasive robotic surgery [3][4][5]. An additional advantage of robot-assisted surgery is to reduce hand tremor, which can be transferred from the surgeon's hands to the patient's body in classical surgery.…”

“…One important problem in robotic surgery architectures is that tactile feedback is very difficult to implement on MIRIs. In order to increase surgeons' capabilities to carry out surgical operations, tactile information must be transferred to surgeons' hands [3][4][5]. Some critical points preventing the use of tactile/haptic feedback in robot-assisted surgery are:…”

“…The communication delay between the motion of surgeons' hands and the motion of MIRIs may limit perception and induce instability [3][4][5];…”

“…A very interesting surgical instrument is shown in [25], in which CYCLOPS is presented: a robotic tool for endoscopic surgery based on the concept of tendon-driven parallel robots. The cable-driven concept proposed in the paper is in the same line of the one we published in [5], using cables to move a mobile part with respect to the fixed part and with a direct force mapping principle involved, but applied with different methods and design. Other solutions are tested to include force-torque sensors in MIRIs, such as the one included in [26], in which fiber Bragg gratings (FBG) are used.…”