Claudio Quaglia

A New Mechanism for Mesoscale Legged Locomotion in Compliant Tubular Environments

We present design and experimental performance results for a novel mechanism for robotic legged locomotion at the mesoscale (from hundreds of microns to tens of centimeters). The new mechanism is compact and strikes a balance between conflicting design objectives, exhibiting high foot forces and low power consumption. It enables a small robot to traverse a compliant, slippery, tubular environment, even while climbing against gravity. This mechanism is useful for many mesoscale locomotion tasks, including endoscopic capsule robot locomotion in the gastrointestinal tract. It has enabled fabrication of the first legged endoscopic capsule robot whose mechanical components match the dimensions of commercial pill cameras (11 mm diameter by 25 mm long). A novel slot-follower mechanism driven via lead screw enables the mechanical components of the capsule robot to be as small while simultaneously generating 0.63 N average propulsive force at each leg tip. In this paper, we describe kinematic and static analyses of the lead screw and slot-follower mechanisms, optimization of design parameters, and experimental design and tuning of a gait suitable for locomotion. A series of ex vivo experiments demonstrate capsule performance and ability to traverse the intestine in a manner suitable for inspection of the colon in a time period equivalent to standard colonoscopy.

Design of a Novel Bimanual Robotic System for Single-Port Laparoscopy

This paper presents the design and fabrication of Single-Port lapaRoscopy bImaNual roboT (SPRINT), a novel teleoperated robotic system for minimally invasive surgery. SPRINT, specifically designed for single-port laparoscopy, is a high-dexterity miniature robot, able to reproduce the movement of the hands of the surgeon, who controls the system through a master interface. It comprises two arms with six degrees of freedom (DOFs) that can be individually inserted and removed in a 30-mm-diameter umbilical access port. The system is designed to leave a central lumen free during operations, thus allowing the insertion of other laparoscopic tools. The four distal DOFs of each arm are actuated by on-board brushless dc motors, while the two proximal DOFs of the shoulder are actuated by external motors. The constraints generated by maximum size and power requirements led to the design of compact mechanisms for the actuation of the joints. The wrist is actuated by three motors hosted in the forearm, with a peculiar differential mechanism that allows us to have intersecting roll-pitch-roll axes. Preliminary tests and validations were performed ex vivo by surgeons on a first prototype of the system.

Design, Fabrication, and Testing of a Capsule With Hybrid Locomotion for Gastrointestinal Tract Exploration

This paper describes a novel solution for the active locomotion of a miniaturized endoscopic capsule in the gastrointestinal (GI) tract. The authors present the design, development, and testing of a wireless endocapsule with hybrid locomotion, where hybrid locomotion is defined as the combination between internal actuation mechanisms and external magnetic dragging. The capsule incorporates an internal actuating legged mechanism, which modifies the capsule profile, and small permanent magnets, which interact with an external magnetic field, thus imparting a dragging motion to the device. The legged mechanism is actuated whenever the capsule gets lodged in collapsed areas of the GI tract. This allows modification of the capsule profile and enables magnetic dragging to become feasible and effective once again. A key component of the endoscopic pill is the internal mechanism, endowed with a miniaturized brushless motor and featuring compact design, and adequate mechanical performance. The internal mechanism is able to generate a substantial force, which allows the legs to open against the intestinal tissue that has collapsed around the capsule body. An accurate simulation of the performance of the miniaturized motor under magnetic fields was carried out in order to define the best configuration of the internal permanent magnets (which are located very close to the motor) and the best tradeoff operating distance for the external magnet, which is responsible for magnetically dragging the capsule. Finally, a hybrid capsule was developed generating 3.8 N at the tip of the legged mechanism and a magnetic link force up to 135 mN. The hybrid capsule and its wireless control were extensively tested in vitro, ex vivo , and in vivo, thus confirming fulfilment of the design specifications and demonstrating a good ability to manage collapsed areas of the intestinal tract.

Wireless therapeutic endoscopic capsule: in vivo experiment.

BACKGROUND AND STUDY AIM Capsule endoscopy is becoming well established as a diagnostic technique for the gastrointestinal tract. Nevertheless swallowable capsule devices that can effectively perform surgical and therapeutic interventions have not yet been developed. Such devices would also be a valuable support for natural orifice transluminal endoscopic surgery (NOTES). The objective of this study was to assess the feasibility of using a swallowable wireless capsule to deploy a surgical clip under remote control. MATERIALS AND METHODS A wireless endoscopic capsule, diameter 12.8 mm and length 33.5 mm, was developed. The device is equipped with four permanent magnets, thus enabling active external magnetic steering. A nitinol clip is loaded on the topside of the capsule, ready to be released when a control command is issued by an external operator. Repeated ex vivo trials were done to test the full functionality of the therapeutic capsule in terms of efficiency in releasing the clip and reliability of the remote control. An in vivo test was then carried out in a pig: the capsule was inserted transanally and steered by means of an external magnetic arm towards an iatrogenic bleeding lesion. The clip, mounted on the tip of the capsule, was released in response to a remote signal. The procedure was observed by means of a flexible endoscope. RESULTS A wireless capsule clip-releasing mechanism was developed and tested. During ex vivo trials, the capsule was inserted into the sigmoid section of a phantom model and steered by means of the external magnet to a specific target, identified by a surgical suture at a distance of 3 cm before the left flexure. The capsule took 3 to 4 minutes to reach the desired location moving under external magnetic guidance, while positioning of the capsule directly on the target took 2 to 3 minutes. Successful in vivo clipping of an iatrogenic bleed by means of a wireless capsule was demonstrated. CONCLUSIONS This study reports the first successful in vivo surgical experiment using a wireless endoscopic capsule, paving the way to a new generation of capsule devices able to perform both diagnostic and therapeutic tasks.

A magnetic internal mechanism for precise orientation of the camera in wireless endoluminal applications

BACKGROUND AND STUDY AIMS The use of magnetic fields to control operative devices has been recently described in endoluminal and transluminal surgical applications. The exponential decrease of magnetic field strength with distance has major implications for precision of the remote control. We aimed to assess the feasibility and functionality of a novel wireless miniaturized mechanism, based on magnetic forces, for precise orientation of the camera. MATERIALS AND METHODS A remotely controllable endoscopic capsule was developed as proof of concept. Two intracapsular moveable permanent magnets allow fine positioning, and an externally applied magnetic field permits gross movement and stabilization. Performance was assessed in ex vivo and in vivo bench tests, using porcine upper and lower gastrointestinal tracts. RESULTS Fine control of capsule navigation and rotation was achieved in all tests with an external magnet held steadily about 15 cm from the capsule. The camera could be rotated in steps of 1.8 degrees . This was confirmed by ex vivo tests; the mechanism could adjust the capsule view at 40 different locations in a gastrointestinal tract phantom model. Full 360 degrees viewing was possible in the gastric cavity, while the maximal steering in the colon was 45 degrees in total. In vivo, a similar performance was verified, where the mechanism was successfully operated every 5 cm for 40 cm in the colon, visually sweeping from side to side of the lumen; 360 degrees views were obtained in the gastric fundus and body, while antrally the luminal walls prevented full rotation. CONCLUSIONS We report the feasibility and effectiveness of the combined use of external static magnetic fields and internal actuation to move small permanent intracapsular magnets to achieve wirelessly controllable and precise camera steering. The concept is applicable to capsule endoscopy as to other instrumentation for laparoscopic, endoluminal, or transluminal procedures.

Wireless steering mechanism with magnetic actuation for an endoscopic capsule

This paper illustrates the design, development and testing of a miniature mechanism to be integrated in endoscopic capsules for precise steering capabilities (Magnetic Internal Mechanism, MIM). The mechanism consists of an electromagnetic motor connected to a couple of small permanent magnets and immersed in a static magnetic field produced by an external permanent magnet or a by an electromagnetic coil. The overall steering capsule, integrating the magnetic steering mechanism and the vision system is 15.6 mm in diameter, 48 mm in length, 14.4 g in weight and can be oriented with an accuracy of 0.01°. As regards system scalability, the capsule size could be reduced down to 11 mm in diameter by optimizing some mechanical components. On the other hand, the magnets size cannot be reduced because the magnetic link between internal and external magnets at typical operation distances (about 15 mm) would be weak.

Anchoring frame for intra-abdominal surgery

Natural orifice transluminal endoscopic surgery (NOTES) is one of the modern surgical techniques that led to the miniaturization of surgical tools and brings the concept of inserting many robotic units into the peritoneal cavity for executing “scarless” surgical tasks. However, the development of transabdominal anchoring systems that guarantee stability is recognized as a challenging issue in the design of miniature intra-abdominal robotic devices. A dedicated platform, exploiting magnetic coupling for anchoring, has been designed by respecting anatomical constraints, maximizing the volume to increase the number of embedded magnets, and consequently incrementing operating distance. The device is equipped with a SMA (shape memory alloy) mechanism that allows configuration change from an extended cylindrical (compliant for deployment) to a compact triangular (rigid for providing stability) design. The feasibility and the potential of the proposed platform have been demonstrated both in in vitro and in in vivo conditions on a human phantom and a porcine model, respectively.

Hand-held robotic instrument for dextrous laparoscopic interventions

Surgical instruments used in many types of minimally invasive procedures are rigid or only limitedly flexible. Some common tasks like suturing, require precise and dextrous movements that are difficult to perform by means of instruments with limited degrees of freedom (DOF).

A miniaturized robotic platform for natural orifice transluminal endoscopic surgery: in vivo validation

AbstractBackgroundNatural orifice transluminal endoscopic surgery (NOTES) involves accessing the abdominal cavity via one of the body natural orifices for enabling minimally invasive surgical procedures. However, the constraints imposed by the access modality and the limited available technology make NOTES very challenging for surgeons. Tools redesign and introduction of novel surgical instruments are imperative in order to make NOTES operative in a real surgical scenario, reproducible and reliable. Robotic technology has major potential to overcome current limitations.MethodsThe robotic platform described here consists of a magnetic anchoring frame equipped with dedicated docking/undocking mechanisms to house up to three modular robots for surgical interventions. The magnetic anchoring frame guarantees the required stability for surgical tasks execution, whilst dedicated modular robots provide the platform with adequate vision, stability and manipulation capabilities. ResultsPlatform potentialities were demonstrated in a porcine model. Assessment was organized into two consecutive experimental steps, with a hybrid testing modality. First, platform deployment, anchoring and assembly through transoral–transgastric access were demonstrated in order to assess protocol feasibility and guarantee the safe achievement of the following experimental session. Second, transabdominal deployment, anchoring, assembly and robotic module actuation were carried out.Conclusions This study has demonstrated the feasibility of inserting an endoluminal robotic platform composed of an anchoring frame and modular robotic units into a porcine model through a natural orifice. Once inserted into the peritoneal cavity, the platform provides proper visualization from multiple orientations. For the first time, a platform with interchangeable modules has been deployed and its components have been connected, demonstrating in vivo the feasibility of intra-abdominal assembly. Furthermore, increased dexterity employing different robotic units will enhance future system capabilities.

Bioinspired Robotic Dual-Camera System for High-Resolution Vision

Due to the limited resolution of both cameras and displays, acuity of artificial vision systems is currently well below the human eye. Visual acuity, in cameras as well as in animal eyes, can be increased by making smaller receptors or bigger eyes. In some applications, the size of the camera is constrained, so alternative solutions must be sought. This paper presents a robotic dual-camera vision system whose design is inspired by the visual system of jumping spiders (Salticidae family). The system is composed of a telephoto camera whose field of view (FOV) can be moved within the larger FOV of a wide-angle camera and allows to form a high-resolution image, i.e., an image with the FOV of the wide-angle camera, yet having the same resolution as the telephoto camera. We describe the design of the robotic system, the direct and inverse kinematics, and the image processing algorithms that allow to build the high-resolution image. Images from experiments are presented, together with a discussion on sources of errors and possible solutions. The system is particularly useful for fixed-camera monitoring or teleoperation applications, such as remote surveillance and minimally invasive surgery. The system achieves seven times higher resolution than typical commercial endoscopes.