Force-sensing Capability Research Articles

S-Surge: Novel Portable Surgical Robot with Multiaxis Force-Sensing Capability for Minimally Invasive Surgery

To achieve a compact and lightweight surgical robot with force-sensing capability, in this paper, we propose a surgical robot called “S-surge,” which is developed for robot-assisted minimally invasive surgery, focusing mainly on its mechanical design and force-sensing system. The robot consists of a 4-degree-of-freedom (DOF) surgical instrument and a 3-DOF remote center-of-motion manipulator. The manipulator is designed by adopting a double-parallelogram mechanism and spherical parallel mechanism to provide advantages such as compactness, simplicity, improved accuracy, and high stiffness. Kinematic analysis was performed in order to optimize workspace. The surgical instrument enables multiaxis force sensing including a three-axis pulling force and single-axis grasping force. In this study, it will be verified that it is feasible to carry the entire robot around thanks to its light weight (4.7 kg); therefore, allowing the robot to be applicable for telesurgery in remote areas. Finally, it will be explained how we experimented with the performance of the robot and conducted tissue manipulating task using the motion and force sensing capability of the robot in a simulated surgical setting.

A Three-Dimensional Shape-Based Force and Stiffness-Sensing Platform for Tendon-Driven Catheters.

This paper presents an efficient shape-based three-axial force and stiffness estimator for active catheters commonly implemented in cardiac ablation. The force-sensing capability provides important feedback for catheterization procedures including real-time control and catheter steering in autonomous navigation systems. The proposed platform is based on the introduced accurate and computationally efficient Cosserat rod model for tendon-driven catheters. The proposed nonlinear Kalman filter formulation for contact force estimation along with the developed catheter model provides a real-time force observer robust to nonlinearities and noise covariance uncertainties. Furthermore, the proposed platform enables stiffness estimation in addition to tip contact force sensing in different operational circumstances. The approach incorporates pose measurements which can be achieved using currently developed pose-sensing systems or imaging techniques. The method makes the approach compatible with the range of forces applied in clinical applications. The simulation and experimental results verify the viability of the introduced force and stiffness-sensing technique.

Automation Highlights from the Literature

Automation Highlights from the Literature

Quantitative pediatric surgical skill assessment using a rapid-prototyped chest model

Introduction: Though minimally invasive pediatric surgery has become more widespread, pediatric-specific surgical skills have not been quantitatively assessed. Material and methods: As a first step toward the quantification of pediatric-specific surgical skills, a pediatric chest model comprising a three-dimensional rapid-prototyped pediatric ribcage with accurate anatomical dimensions, a suturing skin model with force-sensing capability, and forceps with motion-tracking sensors were developed. A skill assessment experiment was conducted by recruiting 16 inexperienced pediatric surgeons and 14 experienced pediatric surgeons to perform an endoscopic intracorporeal suturing and knot-tying task in both the pediatric chest model setup and the conventional box trainer setup. Results: The instrument motion measurement was successful in only 20 surgeons due to sensor failure. The task completion time, total path length of instruments, and applied force were compared between the inexperienced and experienced surgeons as well as between the box trainer and chest model setups. The experienced surgeons demonstrated better performance in all parameters for both setups, and the pediatric chest model was more challenging due to the pediatric features replicated by the model. Conclusion: The pediatric chest model was valid for pediatric skill assessment, and further analysis of the collected data will be conducted to further investigate pediatric-specific skills.

A Laparoscopic Grasping Tool with Force Sensing Capability

This paper presents a laparoscopic grasping tool for minimally invasive surgery with the capability of multiaxis force sensing. The tool is able to sense three-axis Cartesian manipulation force and a single-axis grasping force. The forces are measured by a wrist force sensor located at the distal end of the tool, and two torque sensors at the tool base, respectively. We propose an innovative design of a miniature force sensor achieving structural simplicity and potential cost effectiveness. A prototype is manufactured and experiments are conducted in a simulated surgical environment by using an open platform for surgical robot research, called Raven-II.

Tactile-direction-sensitive and stretchable electronic skins based on human-skin-inspired interlocked microstructures.

Stretchable electronic skins with multidirectional force-sensing capabilities are of great importance in robotics, prosthetics, and rehabilitation devices. Inspired by the interlocked microstructures found in epidermal-dermal ridges in human skin, piezoresistive interlocked microdome arrays are employed for stress-direction-sensitive, stretchable electronic skins. Here we show that these arrays possess highly sensitive detection capability of various mechanical stimuli including normal, shear, stretching, bending, and twisting forces. Furthermore, the unique geometry of interlocked microdome arrays enables the differentiation of various mechanical stimuli because the arrays exhibit different levels of deformation depending on the direction of applied forces, thus providing different sensory output patterns. In addition, we show that the electronic skins attached on human skin in the arm and wrist areas are able to distinguish various mechanical stimuli applied in different directions and can selectively monitor different intensities and directions of air flows and vibrations.

FORCE-BASED AUTOMATIC CLASSIFICATION OF BASIC MANIPULATIONS WITH GRASPING FORCEPS

Haptic information is crucial for the execution of precise and dexterous manipulations. During minimally invasive surgery, doctors are required to indirectly sense force-related information from body organs and tissues via a surgical instrument because they cannot directly touch the tissue. Against such a background, skill evaluation based on force measurement is useful for judging whether a person has adequate manipulation skills. This paper addresses the challenge of automatically classifying basic manipulations performed with surgical grasping forceps. First, manipulations performed with forceps during laparoscopic surgery were categorized into four basic types from video observation. Grasping forceps with force-sensing capability were developed to support identification of these types, which were automatically classified by monitoring information on the force applied to the forceps. An experiment to investigate the efficacy of the proposed method produced manipulation logs showing that doctors are capable of conducting tasks with less force than novices. It was also confirmed that the prototype forceps are suitable for practical use in animal experiments.

Design and Evaluation of 2-DOF Compliant Forceps With Force-Sensing Capability for Minimally Invasive Robot Surgery

In this paper, a novel concept of two-degree-of-freedom (2-DOF) compliant forceps is suggested for the measure of pulling and grasp forces at the tip of surgical instrument for minimally invasive surgery robot. For the design of the compliant forceps, the required compliance characteristics are first defined using a simple spring model with one linear and one torsional springs. This model may be directly realized as the compliant forceps. However, for the compact realization of the mechanism, we synthesize the spring model with two torsional springs that has equivalent compliance characteristics to the linear-torsional spring model. Then, each of the synthesized torsional springs is realized physically by means of a flexure hinge. From this design approach, direct measurement of the pulling and grasp forces is possible at the forceps, and measuring sensitivity can be adjusted in the synthesis process. The validity of the design is evaluated by finite element analysis. Further, from the measured values of bending strains of two flexure hinges, a method to compute the decoupled pulling and grasp forces is presented via the theory of screws. Finally, force-sensing performance of the proposed compliant forceps is verified from the experiments of the prototype using some weights and load cells.

Inroads Toward Robot-Assisted Cochlear Implant Surgery Using Steerable Electrode Arrays

Robotic insertions of actively steerable perimodiolar electrode arrays can substantially reduce insertion forces and prevent electrode buckling. Perimodiolar electrodes have been proven to be effective in reducing insertion forces. However, the dedicated techniques of atraumatic electrode insertion require intensive surgeon training. Although some specialized medical robots have been developed to help surgeons in certain minimally invasive surgeries, none are applicable to electrode insertions. A robot prototype capable of automatically inserting novel steerable electrode array and adjusting its approach angle toward the scala tympani has been constructed and tested. Comparisons of insertion forces using robotically assisted steerable and straight electrodes on scala tympani models are presented. Simulations and experiments are conducted to compare the robotic insertion outcomes and insertion forces. The use of robotically assisted steerable electrodes for insertions significantly reduces the insertion forces compared with straight electrodes. Based on the results from the experiments, a second-generation robot with insertion force-sensing capability and haptic control to be used in the operating room has been designed for cochlear implant surgery. Preliminary experimental results using robot-assisted steerable electrode prototype show that it is effective in reducing insertion forces and preventing electrode buckling. A second-generation robot has been designed and constructed for cochlear implant surgery under operating room conditions.

A mechatronic platform for early diagnosis of neurodevelopmental disorders

Neurodevelopmental engineering is a new interdisciplinary research area at the intersection of developmental neuroscience and biomedical engineering, mainly concerned with quantitative analysis and modeling of human behaviour during neural development. Along such a line, our research focuses on early diagnosis of neurodevelopmental disorders such as autism, typically diagnosed after 2–3 years of age. With the purpose of beating new paths in the emerging field of neurodevelopmental engineering, we propose a novel approach to the assessment of basic patterns of goal-directed actions in developing babies, in the 0–24 months of age range, both under laboratory and naturalistic conditions. In particular, we propose novel mechatronic devices, either wearable or embedded into toys, for ecological, unobtrusive assessment of infant behavior. Guidelines for the design of a particular toy embedding both kinematics and force-sensing capabilities as well as of experimental scenarios where similar instrumented toys can be deployed are provided. Preliminary experiments for the technical validation of an early prototype in ecological conditions are also presented.

Reliable, Built-in, High-Accuracy Force Sensing for Legged Robots

An approach for achieving reliable, built-in, high-accuracy force sensing for legged robots is presented, based on direct exploitation of the properties of a robot’s mechanical structure. The proposed methodology relies on taking account of force-sensing requirements at the robot design stage, with a view to embedding force-sensing capability within the mechanical structure of the robot itself. The test case is ROBOCLIMBER, a bulky, quadruped climbing and walking machine whose weighty legs enable it to carry out heavy-duty drilling operations. The paper shows that, with finite-element analysis of ROBOCLIMBER’s mechanical configuration during the design stage, candidate positions can be selected for the placement of force transducers to measure indirectly the contact forces between the feet and the ground. Force sensors are then installed at the theoretically best positions on the mechanical structure, and several experiments are carried out to calibrate all sensors within their operational range of interest. After calibration, the built-in sensors are subjected to experimental performance evaluation, and the final best sensor option is found. The built-in force-sensing capability thus implemented is subjected to its first test of usability when it is employed to compute the actual centre of gravity of ROBOCLIMBER. The method is shown to be useful for determining variation during a gait (due to the non-negligible weight of the legs). Afterwards the force sensors are shown to be useful for controlling foot-ground interaction, and several illustrative experiments confirm the high sensitivity, reliability and accuracy of the selected approach. Lastly, the built-in sensors are used to measure ground-reaction forces and to compute the zero-moment point for ROBOCLIMBER in real time, both while standing and while executing a dynamically balanced gait.

Control of Manipulator with Force Sensing Capability

Abstract It is rather a difficult task to use force sensing informa-tion for a manipulator motion control. We propose to form complex motions as a superposition of a limited set of basic procedures. A number of tasks including arbitrarily positioned objects hanlding and constrained motion can be solved using this approach. To develope the approach real-life features of the problems in question are to be taken into consideration. To this end mathematical models of transient processes in the considered system are studied. Allowable ranges of force feedback gain are investigated, taking into account a delay in the control loop, compliance or backlash in structure. The case of nonideal constraint is also studied. Manipulator control at the fettling process is built up here.