A key component to the success of master-slave surgical systems is the quality of the master interface used to relay the surgeon's instructions to the slave robot. In previous work the authors developed a gaze-assisted intention recognition scheme, allowing the system to dynamically adapt the motion scaling based on where the user is trying to reach. This allowed users to perform tasks significantly more quickly and with less need for clutching. However, the system possessed a number of core parameters that were manually optimized, potentially providing a non-optimal solution depending on the user. This paper presents a Bayesian approach to the problem of optimizing a human-robot interface in a user-specific manner. Two Bayesian optimization methods are studied: one in which users are asked to grade robot behavior for a given set of parameters, and one where only preference relative to other parameter sets is expressed. The performance of these optimizations is evaluated in a blind comparison user study, demonstrating that the optimized parameters are preferred to the manually optimized ones in over 90 % of cases after only 12 test samples. These parameters are further shown to perform at least as well as the manually optimized ones in all cases, and showing statistically significant improvement in the case of the graded optimization.

The use of snake-like robots for surgery is a popular choice for intra-luminal procedures. In practice, the requirements for strength, flexibility and accuracy are difficult to be satisfied simultaneously. This paper presents a computational approach for optimizing the design of a snake-like robot using serial rolling-joints and tendons as the base architecture. The method optimizes the design in terms of joint angle range and tendon placement to prevent the tendons and joints from colliding during bending motion. The resulting optimized joints were manufactured using 3D printing. The robot was characterized in terms of workspace, dexterity, precision and manipulation forces. The results show a repeatability as low as 0.9mm and manipulation forces of up to 5.6N.

Traditional robotic surgical systems rely entirely on robotic arms to triangulate articulated instruments inside the human anatomy. This configuration can be ill-suited for working in tight spaces or during single access approaches, where little to no triangulation between the instrument shafts is possible. The control of these instruments is further obstructed by ergonomic issues: The presence of motion scaling imposes the use of clutching mechanics to avoid the workspace limitations of master devices, and forces the user to choose between slow, precise movements, or fast, less accurate ones. This paper presents a bi-manual system using novel self-triangulating 6-degrees-of-freedom (DoF) tools through a flexible elbow, which are mounted on robotic arms. The control scheme for the resulting 9-DoF system is detailed, with particular emphasis placed on retaining maximum dexterity close to joint limits. Furthermore, this paper introduces the concept of gaze-assisted adaptive motion scaling. By combining eye tracking with hand motion and instrument information, the system is capable of inferring the user's destination and modifying the motion scaling accordingly. This safe, novel approach allows the user to quickly reach distant locations while retaining full precision for delicate manoeuvres. The performance and usability of this adaptive motion scaling is evaluated in a user study, showing a clear improvement in task completion speed and in the reduction of the need for clutching.

Snake like continuum robots are increasingly used for minimally invasive surgery. Most robotic devices of this sort that have been reported to date are controlled in an open loop manner. Using shape sensing to provide closed loop feedback would allow for more accurate control of the robot's position and, hence, more precise surgery. Fiber Bragg Gratings, magnetic sensors and optical reflectance sensors have all been reported for this purpose but are often limited by their cost, size, stiffness or complexity of fabrication. To address this issue, we designed, manufactured and tested a prototype two-link robot with a built-in fiber-optic shape sensor that can deliver and control the position of a CO2-laser fiber for soft tissue ablation. The shape sensing is based on optical reflectance, and the device (which has a 4 mm outer diameter) is fabricated using 3D printing. Here we present proof-of-concept results demonstrating successful shape sensing - i.e. measurement of the angular displacement of the upper link of the robot relative to the lower link - in real time with a mean measurement error of only 0.7°.

Suturing is an essential requirement for surgical robots. Current designs of needle drivers require significant forces to be applied so that the needle will not flip or slip between the jaws when inserted into the tissue. The required force implies that most designs are based on rigid instruments with a straight shaft that induces less dexterity. Flexible robotics provides great dexterity to achieve the task, although often it lacks the capability to apply large forces and therefore hold the surgical needle firmly. Solutions can be found in how the needle driver's jaws are designed. This paper presents improved designs for needle grasping tools for flexible robotic instruments, to be produced directly with selective laser melting. Features on the gripping surface were embedded to increase the gripping effectiveness even in the presence of limited grasping force. A detailed characterisation has been performed for each design showing improvements with respect to the state of the art.

The performance of a master-slave robotic system depends significantly on the ergonomics and the capability of its master device to correctly interface the user with the slave robot. Master manipulators generating commands in task space represent a commonly adopted solution for controlling a range of slave robots while retaining an ergonomic design. However, these devices present several drawbacks, such as requiring the use of clutching mechanics to compensate for the mismatch between slave and master workspaces, and the lack of capability to intuitively transmit important information such as specific joint limits to the user. In this paper, a novel joint-space master manipulator is presented. This manipulator emulates the kinematic structure of highly flexible surgical instruments which it is designed to control. This system uses 6 active degrees of freedom to compensate for its own weight, as well as to provide force feedback corresponding to the slave robot's joint limits. A force/torque sensor integrated at the end effector is used to relay user-generated forces and torques directly to specific joints. This is performed to counteract the friction stemming from structural constraints imposed by the kinematic design of the instruments. Finally, a usability study is carried out to test the validity of the system, proving that the instruments can be intuitively controlled even at the extremities of the workspace.

This paper introduces the design and characterization of a robotic surgical instrument produced mainly with rapid prototyping techniques. Surgical robots have generally complex structures and have therefore an elevated cost. The proposed instrument was designed to incorporate minimal number of components to simplify the assembly process by leveraging the unique strength of rapid prototyping for producing complex, assemble-free components. The modularity, cost-effectiveness and fast manufacturing and assembly features offer the possibility of producing patient or task specific instruments. The proposed robot incorporates an integrated force measurement system, thus allowing the determination of the force exchanged between the instrument and the environment. Detailed experiments were performed to validate the functionality and force sensing capability of the instrument.

Additive manufacturing is a technology in constant evolution. It is able to produce objects otherwise either impractical or unfavorable for traditional manufacturing technologies, especially in relatively limited quantities. The advancement of Selective Laser Melting (SLM) has made it possible to manufacture functional, production-quality components directly from rapid prototyping for long-term use. This work studies the SLM process and identifies the optimal process parameters for the rapid manufacturing of a miniaturized robotic surgical instrument. The proposed robotic instrument has been designed to exploit the advantages of rapid manufacturing and rapid assembly, following a shift from large scale manufacturing of generalized surgical instruments to the production of small batches of patient or procedure-specific.

Recent work on probe-based confocal endomicroscopy has demonstrated its potential role for real-time assessment of tumour margins during breast conserving surgery. However, endomicroscope probes tend to have a very small field-of-view, making surveillance of large areas of tissue difficult, and limiting practical clinical deployment. In this paper, a new robotic device for controlled, large area scanning based on a fibre bundle endomicroscope probe is proposed. The prototype uses a 2-DOF mechanism (−90 to +90 degrees bending on one axis, 360 degrees of rotation on a second axis) as well as a passive linear structure to conform to undulating surfaces. Both axes are driven by brushless DC servo motors with computer control, thus facilitating large field-of-view mosaicing. Experimental results have shown good repeatability and low hysteresis of the device, which is able to scan different surface trajectories (e.g. a spiral pattern over a hemi-spherical surface) with consistent tissue contact. Ex vivo human breast tissue results are demonstrated, illustrating a viable scanning approach for breast endomicroscopy.

Precise and repetitive positional control of surgical robots is important to reduce time and risks of surgical procedures. These factors become particularly important when deploying the surgical system through a flexible path to areas with a tight workspace such as the stomach or oesophagus where high dexterity, flexibility, accuracy and stability are required. This paper presents a flexible access robot combining articulated joints and continuum flexible section for both transluminal and endoluminal surgeries. Kinematic model and control strategy for the flexible robot are described in the paper. The experiment simulating a transoral gastric procedure demonstrates great flexibility and dexterity of the device. The results show that good accuracy and repetitive control of the device are achieved, which demonstrate the potential application of the device for transluminal or endoluminal surgery.

Real-time shape sensing and state acquisition is important for closed-loop control of hyper-redundant snake robots in minimally invasive surgery. Due to the miniaturized size of such minimally invasive surgery robots, it is not feasible to use existing angular sensors involving rotary encoders. With recent advances of the MEMS technology, micro inertial sensors have shown their potential for robot state estimation. Previous studies have demonstrated that accurate joint angles can be estimated for one degree-of-freedom (DoF) joints. However, higher DoF joints of the robot can impose a number of challenges to the current joint angle estimation methods. This paper presents a micro-sensing platform and shape reconstruction algorithm for minimally invasive surgery snake robot with two DoF joints. The method incorporates both gravitational and gyroscopic sensing for calculating the rotation difference between any consecutive robot segments. The gyroscope measurements are first used as the input to predict the rotation difference by direct orientation integration. The orientation difference is then derived from the consecutive acceleration vectors to update the prediction through a complementary filter. To demonstrate the performance of our proposed approach, a robot prototype with two universal joints was fabricated. Detailed experimental results have demonstrated that high accuracy can be achieved by using the proposed method for joint angle estimation.