Modeling of a compliant joint in a Magnetic Levitation System for an endoscopic camera

Abstract

Abstract.A novel compliant Magnetic Levitation System (MLS) for a wired miniature surgical camera robot was designed, modeled and fabricated. The robot is composed of two main parts, head and tail, linked by a compliant beam. The tail module embeds two magnets for anchoring and manual rough translation. The head module incorporates two motorized donut-shaped magnets and a miniaturized vision system at the tip. The compliant MLS can exploit the static external magnetic field to induce a smooth bending of the robotic head (0-80• ), guaranteeing a wide span tilt motion of the point of view. A nonlinear mathematical model for compliant beam was developed and solved analytically in order to describe and predict the trajectory behaviour of the system for different structural parameters. The entire device is 95 mm long and 12.7 mm in diameter. Use of such a robot in single port or standard multiport laparoscopy could enable a reduction of the number or size of ancillary trocars, or increase the number of working devices that can be deployed, thus paving the way for multiple view point laparoscopy.

Example Application

“…The bottom is held in place by inserting the pole end pin c to a grommet on the tent fabric d. (2) Tent pole segments e are connected using a flexible cord f, and are inserted into grommets using pins c. The poles are connected at the midpoint b.…”

“…(1) (2) The joint in a magnetic levitation system for an endoscopic camera is designed compliant as a flexible cantilever beam. The beam deflection is due to the end-point load and moment, which are representative of the weight of the camera and the magnetic load [1,2].…”

“…(1) (2) A disposable dental floss pick exhibits the key functional elements of contact-aided compliant mechanisms. The two symmetric halves of the floss pick are connected at three locations: via an inextensible floss segment at the left end of a via b compliant segment that ends in a toothpick and via c a flexure joint in between these two ends.…”

Mesoscale mobile robots for gastrointestinal minimally invasive surgery (MIS)

“…The mesoscale (broadly defined as 1-100 mm) includes robots that are small, but easily visible and manipulable by unaided human eyes and hands. although there do exist some robots in this category designed to be inserted through incisions (Lehman et al, 2009;Patronik et al, 2009;Platt et al, 2009;rentschler et al, 2006;simi et al, 2012), many more robots in this category are designed to be swallowable.…”

A magnetic levitation robotic camera for minimally invasive surgery: Useful for NOTES?

“…Furthermore the main benefit stems from the robotized innovative embedded mechanism that exploits the static external magnetic field to induce a precise smooth bending of the robotic head, activated by a push button interface, guaranteeing a wide span (0-80°) tilt motion of the point of view. The monolithic nature of compliant mechanisms have the advantage of no wear debris, no pinch points, and no need for lubrication, which are critical in the sensitive internal body environment, furthermore it also simplifies the sterilization processes 14 . A thin flexible cable guarantees robot powering, real time signal transmission and an effective retrieval of the device in case of failure.…”