Single port access surgery (SPAS) presents surgeons with added challenges that require new surgical tools and surgical assistance systems with unique capabilities. To address these challenges, we designed and constructed a new insertable robotic end-effectors platform (IREP) for SPAS. The IREP can be inserted through a Ø15 mm trocar into the abdomen and it uses 21 actuated joints for controlling two dexterous arms and a stereo-vision module. Each dexterous arm has a hybrid mechanical architecture comprised of a two-segment continuum robot, a parallelogram mechanism for improved dual-arm triangulation, and a distal wrist for improved dexterity during suturing. The IREP is unique because of the combination of continuum arms with active and passive segments with rigid parallel kinematics mechanisms. This paper presents the clinical motivation, design considerations, kinematics, statics, and mechanical design of the IREP. The kinematics of coordination between the parallelogram mechanisms and the continuum arms is presented using the pseudo-rigid-body model of the beam representing the passive segment of each snake arm. Kinematic and static simulations and preliminary experiment results are presented in support of our design choices.

Multi-backbone continuum robots demonstrated potentials for dexterous manipulation with proper payload capability in minimally invasive surgeries. Most prior works assume constant curvature shapes of the continuum segments in the modeling and control of the multi-backbone continuum robots. The actuation coupling effects between adjacent continuum segments and the segments' variable curvature shapes under environmental interactions have not been fully addressed by a static-kinematic model specifically for multi-backbone continuum robots. This letter hence proposes a variable curvature model for multi-backbone continuum robots with relatively low bending curvature based on the Cosserat rod theory. The model focuses on the major factors that affect the robot's shape: the length-prescribed push-pull actuation, the elastic elongation of the backbone rods, and the external loads. With five assumptions made to simplify the constraints in the multi-backbone continuum robot, a compact statics-kinematics formulation is derived with computational performance acceptable for real-time control. Experiments were conducted on a continuum robotic system to quantify the modeling accuracy and computational efficiency. The proposed model was shown to have substantially improved accuracy over the constant curvature model. The average computational time for solving the inverse kinematics was 0.7ms on a 2.6 GHz Intel i7-5600U platform, which is promising for real-time control.

In the past decades, numerous surgical robotic systems have been developed to improve dexterity, precision, and ergonomics in minimally invasive surgery (MIS). These robotic systems usually have different forms to accommodate the requirements from either multiport or single-port procedures. Unlike the design consensus in the multiport systems where distal-wristed and straight-stemmed instruments are maneuvered by patient-side manipulators, different approaches are still being explored to verify the fulfillment of the clinical and functional requirements from single-port procedures. No systems have been shown to satisfactorily handle both the multiport and the single-port procedures. Utilizing the previously proposed dual continuum mechanism to realize a payload-enhanced multidegree of freedom surgical instrument with a tight bending wrist for intra-abdomen dexterity, it was found that the locations and the number of channels of the access ports can be freely configured. A modular surgical robotic platform is, hence, proposed for handling multiport, single-port, and for the first time hybrid-port procedures. The design concepts, system descriptions, teleoperation kinematics, experimental characterizations, and animal studies are reported. It is expected that suitable invasiveness , where a minimal number of skin incisions can always be used to treat a condition, is to be achieved by the proposed system. True potentials of the proposed system are to be verified in the coming larger scale animal studies and clinical trials.

Purpose: Slim and dexterous manipulators with long reaches can perform various exploration and inspection tasks in confined spaces. This paper aims to present the development of such a dexterous continuum manipulator for potential applications in the aviation industry. Design/methodology/approach: Benefiting from a newly conceived dual continuum mechanism and the improved actuation scheme, this paper proposes a design of a slim and dexterous continuum manipulator. Kinematics modeling, simulation-based dimension synthesis, structural constructions and system descriptions are elaborated. Findings: Experimental validations show that the constructed prototype possesses the desired dexterity to navigate through confined spaces with its kinematics calibrated and actuation compensation implemented. The continuum manipulator with different deployed tools (e.g. graspers and welding guns) would be able to perform inspections and other tasks at remote locations in constrained environments. Research limitations/implications: The current construction of the continuum manipulator possesses quite some friction inside its structure. The bending discrepancy caused by friction could accumulate to an obvious level. It is desired to further reduce the friction, even though the actuation compensation had been implemented. Practical implications: The constructed continuum manipulator could perform inspection and other tasks in confined spaces, acting as an active multi-functional endoscopic platform. Such a device could greatly facilitate routine tasks in the aviation industry, such as guided assembling, inspection and maintenance. Originality/value: The originality and values of this paper mainly lay on the design, modeling, construction and experimental validations of the slim and dexterous continuum manipulator for the desired mobility and functionality in confined spaces.

Robot-assisted laparoscopic minimally invasive surgery has gained significant attentions due to its enhanced dexterity, improved precision, natural eye-hand coordination, etc. In these procedures, stick-like surgical tools with distal wrists are usually maneuvered by multiple patient-side manipulators to perform an operation. These patient-side manipulators shall realize remote center of motion movements and are subject to risks of mutual collisions during motion. On the other hand, the continuum surgical manipulators, often with multiple segments, usually have several degrees of freedom (DoFs) for the movements in a patient's cavity, and only need a lockable bedside stand, rather than a manipulator. However, the continuum segments inherently have limited bending curvature such that large orientation changes of the surgical end effector around confined anatomical features can be challenging. This letter, hence, proposes a modular continuum-articulated laparoscopic robotic tool design with simple and decoupled kinematics. An inverted dual-continuum mechanism is used in the tool to realize pure translations, while a 2-DoF cable-driven distal wrist is incorporated for orientations. The utilized dual-continuum mechanism maintains a constant length across its entire cross section to significantly facilitate maintaining tensions for the actuation cables of the distal wrist. Design concept, kinematics, system descriptions, actuation calibration, and experimental characterizations are reported, demonstrating effectiveness of the proposed idea.