Master-slave Robotic System Research Articles

Estimation of stochastic environment force for master–slave robotic system

The aim of this work is to obtain the maximum likelihood estimate (MLE) of controller-gain parameters \(\widehat{K} \) of the slave robot to determine the stochastic environment force. This is accomplished by measuring the joint positions of master and slave for a known master torque using stochastic difference equation. Here, the environmental force is modelled as a zero-mean white Gaussian random process. Therefore, the joint probability distribution function (pdf) of the slave angle over a given time duration can be computed as a function of the parameters ‘K’. This pdf is maximized with respect to ‘K’ to obtain the MLE of controller-gain parameters. Subsequently, convergence analysis of error in the estimates is performed. Also, an expression of the Cramer–Rao lower bound (CRLB) is derived to measure accuracy of the estimation. Comparison of CRLB with variance of MLE supports that our estimates are asymptotically efficient. The estimation performance is validated analytically and through simulations carried out on a two-link master–slave robotic system.

An assembly-type master-slave catheter and guidewire driving system for vascular intervention.

Current vascular intervention inevitably exposes a large amount of X-ray to both an operator and a patient during the procedure. The purpose of this study is to propose a new catheter driving system which assists the operator in aspects of less X-ray exposure and convenient user interface. For this, an assembly-type 4-degree-of-freedom master-slave system was designed and tested to verify the efficiency. First, current vascular intervention procedures are analyzed to develop a new robotic procedure that enables us to use conventional vascular intervention devices such as catheter and guidewire which are commercially available in the market. Some parts of the slave robot which contact the devices were designed to be easily assembled and dissembled from the main body of the slave robot for sterilization. A master robot is compactly designed to conduct insertion and rotational motion and is able to switch from the guidewire driving mode to the catheter driving mode or vice versa. A phantom resembling the human arteries was developed, and the master-slave robotic system is tested using the phantom. The contact force of the guidewire tip according to the shape of the arteries is measured and reflected to the user through the master robot during the phantom experiment. This system can drastically reduce radiation exposure by replacing human effort by a robotic system for high radiation exposure procedures. Also, benefits of the proposed robot system are low cost by employing currently available devices and easy human interface.

Design and characteristics evaluation of a novel teleoperated robotic catheterization system with force feedback for vascular interventional surgery.

In this paper, we proposed a novel master-slave robotic catheterization system with force feedback for VIS (Vascular Interventional Surgery). The force feedback to the operator on the master side is the key factor to improve the safety during VIS. The developed system used the MR (magneto rheological) fluid to realize force feedback, and it used the developed multidimensional monitoring interface to realize the visualization of force feedback, the developed multidimensional monitoring interface can monitor the motion information of the catheter and contact force between catheter tip or side wall and blood vessel wall, and the motion data of the catheter was collected and generated diagram for reference to surgeon. We have developed a force sensor array to detect the contact force between catheter tip or side wall and blood vessel wall. The force information was detected by the developed contact force sensor array when the catheter contacted with the blood vessel. The force feedback and multidimensional information monitoring interface evaluation experiments were done, the tracking characteristic evaluation experiments were also carried out, the experimental results indicated that the developed novel robotic catheterization system with force feedback and visualization of force feedback is effective for VIS, it can improve the safety during VIS.

高速ビジョンを用いたマスタ・スレーブにおけるボールトラッキングのためのアシスト制御

In recent years, the demand for robots to perform various tasks in dangerous environments has increased. Teleoperated robots are more suitable for dangerous environments than au- tonomous robots. We have developed a master-slave robot system which consists of a light weight master device and a high-power slave robot, and proposed operation assistance methods to improve its dexterity and speedup of the motion. In this paper, we propose an algorithm for tracking a flying ball on the master-slave system. The head of the slave robot is controlled by integrating the operator's command and autonomous visual feedback control so as to track the flying ball. The object motion is predicted by a Kalman filter. The proposed method is verified by experiment.

Design of a haptic device with grasp and push-pull force feedback for a master-slave surgical robot.

We propose a portable haptic device providing grasp (kinesthetic) and push-pull (cutaneous) sensations for optical-motion-capture master interfaces. Although optical-motion-capture master interfaces for surgical robot systems can overcome the stiffness, friction, and coupling problems of mechanical master interfaces, it is difficult to add haptic feedback to an optical-motion-capture master interface without constraining the free motion of the operator's hands. Therefore, we utilized a Bowden cable-driven mechanism to provide the grasp and push-pull sensation while retaining the free hand motion of the optical-motion capture master interface. To evaluate the haptic device, we construct a 2-DOF force sensing/force feedback system. We compare the sensed force and the reproduced force of the haptic device. Finally, a needle insertion test was done to evaluate the performance of the haptic interface in the master-slave system. The results demonstrate that both the grasp force feedback and the push-pull force feedback provided by the haptic interface closely matched with the sensed forces of the slave robot. We successfully apply our haptic interface in the optical-motion-capture master-slave system. The results of the needle insertion test showed that our haptic feedback can provide more safety than merely visual observation. We develop a suitable haptic device to produce both kinesthetic grasp force feedback and cutaneous push-pull force feedback. Our future research will include further objective performance evaluations of the optical-motion-capture master-slave robot system with our haptic interface in surgical scenarios.

Control of a Cable-Driven Platform in a Master–Slave Robotic System: Linear Parameter Varying Approach

Space restrictions prevent surgeons to directly interact with the patient during magnetic resonance imaging (MRI)-guided procedures. One practical solution would be to develop a robotic system that can act as an interface between surgeon and patient during those interventions. The proposed system consists of a commercial PHANTOM device (product of The Sensable Technologies) as the master robot and an MRI-compatible patient-mounted parallel platform (that we name ROBOCATHETER) designed to serve as the slave mechanism inside the scanner bore. As the main contribution of this paper, a linear parameter varying (LPV) gain-scheduling controller is designed and implemented to obtain the desired performance of the slave robot in tracking set points and reference trajectories. To do so, a reduced-order dynamic model of the robot based on the Lagrange method is derived to capture the nonlinear dynamics of the platform. The model is then used for the design of an output-feedback LPV controller to command the robot to position the catheter in any desired states. During the course of control, appropriate selection of scheduling parameters not only helps to compensate for the nonlinearities of the system dynamics but also leads to a set of decoupled models for the system, where each degree-of-freedom (DOF) could be treated separately. The performance of the controller is compared with a variable-gain proportional-derivative-integral (PID) controller. Experimental results show that the proposed control scheme has significant advantages in terms of set point tracking and actuator saturation over the baseline PID controller.

Remote haptic sensing using sliding‐mode assist disturbance observer as force detector

Bilateral controlled master-slave robot system is an important intermediary to realise remote haptic sensing. This study proposes a sliding-mode assist disturbance observer (SMADO) to detect force information in wider bandwidth without force sensors by making use of the fast switching of sliding-mode control values. Moreover, a bilateral control law is proposed based on the SMADO. The proposal tolerates the presence of disturbances and uncertainties in the robots. The influence of these factors is degraded by using the net forces to design the bilateral control rather than employing a robust compensation. This design shows such a feasibility that high performance haptic sensing can be achieved using the SMADO as a wide bandwidth force detector without any robust compensators. The validity of the proposal is confirmed by experiments in practice. The proposal realises the position tracking and action-reaction law between the two robots, which makes the operator vividly feel the remote object.

Bilateral teleoperation with delayed force feedback using time domain passivity controller

Time delay is a long standing impediment of bilateral control and can destabilize the system evidently. This paper presents a mode-based approach to alleviate some of the problems associated with time delays in a master-slave robot system. The originality of the approach proposed mainly lies in its capacity to take into account explicitly the slave force feedback modified according to the output of Passivity Observer (PO). This method consists of a virtual slave environment model together with a PO to calculate the system energy on the master side. The local environment model is built by the parameters that are identified online at the slave side. Simulation results show the superior performance of the proposed control scheme in the presence of time delays. Experimental results, using a 1-DOF master-slave teleoperation system, support this conclusion. Parameters of remote slave environment can be accurately identified by the RLS method.Passivity observer (PO) together with a virtual environment model is built on the local master side and the system passivity can be judged by the PO.Stable force tracking is achieved by the proposed method with time delay.The proposed method is robust to random communication time delay.

Neurological and Robot-Controlled Induction of an Apparition

Tales of ghosts, wraiths, and other apparitions have been reported in virtually all cultures. The strange sensation that somebody is nearby when no one is actually present and cannot be seen (feeling of a presence, FoP) is a fascinating feat of the human mind, and this apparition is often covered in the literature of divinity, occultism, and fiction. Although it is described by neurological and psychiatric patients and healthy individuals in different situations, it is not yet understood how the phenomenon is triggered by the brain. Here, we performed lesion analysis in neurological FoP patients, supported by an analysis of associated neurological deficits. Our data show that the FoP is an illusory own-body perception with well-defined characteristics that is associated with sensorimotor loss and caused by lesions in three distinct brain regions: temporoparietal, insular, and especially frontoparietal cortex. Based on these data and recent experimental advances of multisensory own-body illusions, we designed a master-slave robotic system that generated specific sensorimotor conflicts and enabled us to induce the FoP and related illusory own-body perceptions experimentally in normal participants. These data show that the illusion of feeling another person nearby is caused by misperceiving the source and identity of sensorimotor (tactile, proprioceptive, and motor) signals of one's own body. Our findings reveal the neural mechanisms of the FoP, highlight the subtle balance of brain mechanisms that generate the experience of "self" and "other," and advance the understanding of the brain mechanisms responsible for hallucinations in schizophrenia.

Model-based passive bilateral teleoperation with time delay

Noisy behaviour of time domain passivity control (TDPC) at low velocity is a well known problem for delayed teleoperation systems. This paper presents a novel adaptive model-based passive controller to alleviate some of the noise problems associated with delayed teleoperation system using the TDPC approach. By composing an online estimation of phantom human tissue model and passivity observer on the master side, a high transparency of teleoperation can be achieved while the system passivity is maintained by modifying the damping of the master. The performance of the developed approach was validated using one-degree-of-freedom master–slave robot system with constant time delay. Results show that the phantom tissue parameters can be accurately estimated. In addition, the passivity of the system is observed by the passivity observer using the output of the identified tissue model. Results demonstrate that stable teleoperation with time delay can be achieved and the environment force can be accurately reflected to the operator without chattering.

A novel locally operated master-slave robot system for single-incision laparoscopic surgery

Purpose: Single-incision laparoscopic surgery (SILS) provides more cosmetic benefits than conventional laparoscopic surgery but presents operational difficulties. To overcome this technical problem, we have developed a locally operated master-slave robot system that provides operability and a visual field similar to conventional laparoscopic surgery. Material and methods: A surgeon grasps the master device with the left hand, which is placed above the abdominal wall, and holds a normal instrument with the right hand. A laparoscope, a slave robot, and the right-sided instrument are inserted through one incision. The slave robot is bent in the body cavity and its length, pose, and tip angle are changed by manipulating the master device; thus the surgeon has almost the same operability as with normal laparoscopic surgery. To evaluate our proposed system, we conducted a basic task and an ex vivo experiment. Results: In basic task experiments, the average object-passing task time was 9.50 sec (SILS cross), 22.25 sec (SILS parallel), and 7.23 sec (proposed SILS). The average number of instrument collisions was 3.67 (SILS cross), 14 (SILS parallel), and 0.33 (proposed SILS). In the ex vivo experiment, we confirmed the applicability of our system for single-port laparoscopic cholecystectomy. Conclusion: We demonstrated that our proposed robot system is useful for single-incision laparoscopic surgery.

Implementation of motion transfer in robotic surgery

Minimally invasive surgery is a modern surgical technique in which the operating tools are inserted into the patient through small incisions. Robotic applications in general surgery have evolved from simple surgical assist devices, to more sophisticated systems capable of enhancing surgical performance. The primary class of robots used in general surgery today, are 'master-slave' machines, where the robot mimics the movement of the surgeon. A major drawback with the master-slave robotic systems is the motion coordination between the two. The paper discusses the techniques of motion transfer from master to slave and to implement force feedback from slave to master. Motion is transferred from master surgeon handle to the robotic arm depending on the encoder pulses from master configuration. The pulses from the encoder are processed and fed to the slave, which mimics the hand motion of master configuration. A two channel encoder with DC motor is used in master-slave configuration. The proposed configuration with force feedback capability enables the exact motion coordination between surgeon and robotic surgical system. This technique has a wide application, with accuracy, efficiency, safety and overall user experience that provide superior performance and reliability in master-slave robot-assisted interventions.

3P1-P02 マスタ・スレーブロボットのための実時間自己衝突回避(感覚・運動・計測(2))

3P1-P02 マスタ・スレーブロボットのための実時間自己衝突回避(感覚・運動・計測(2))

3A1-E02 単孔式内視鏡手術のためのローカル操作型マスタ・スレーブロボットシステムの開発(医療ロボティクス・メカトロニクス(1))

3A1-E02 単孔式内視鏡手術のためのローカル操作型マスタ・スレーブロボットシステムの開発(医療ロボティクス・メカトロニクス(1))

Suspension laryngoscopy using a curved-frame trans-oral robotic system

Suspension laryngoscopy has been employed for laryngeal diseases such as treatment for a polyp, cystoma, or granuloma. After securing a straight path with a laryngoscope, the surgeon inserts rigid instruments and examines the target lesion by using a microscope. However, many patients suffer from secondary complications due to the use of a rigid laryngoscope. In addition, about 11-12 % of patients cannot be operated on using laryngoscope because of anatomical restrictions. A surgical method to treat patients using a curved-frame trans-oral robotics system was developed. A new surgical procedure is investigated using a new surgical robot system that employs a curved frame as a guide to insert flexible instruments into the target lesion. For this, a master-slave robotic system was developed, and the performance of the proposed procedure was tested by using a phantom laryngeal model. A routine laryngeal polypectomy procedure was simulated and performed using flexible instruments guided by a master-slave surgical robot in suspension laryngoscopy. A surgical robotic system was able to perform routine procedures to remove a polyp in the vocal cord under clinically realistic conditions on an adult phantom.

Adaptive Fuzzy PID Controller of a Master-Slave Robotic Catheter System in Minimally Invasive Surgery

Minimally Invasive Surgery (MIS) is a good choice to treat cardiovascular disease. However, the accuracy of catheter manipulation is limited by the doctor, and the X-ray damages the health of the doctors. A master-slave Robotic Catheter System (RCS) can solve the disadvantages of the traditional catheter intervention surgery. PID controller has been widely used in the master-slave RCS. However, Traditional PID controller used in the master-slave RCS will cause large overshoot or poor stability. An adaptive fuzzy PID controller can adjust the PID parameters online, reduce the overshoot, and improve the tracking performance of input signal. In this study, the dynamic model of the axial and rotational motion is presented. An adaptive fuzzy PID controller is proposed to improve the performance of the master-slave RCS. Simulation results show that the proposed controller is more effective than the traditional PID control, and the robustness is also improved.

의료용 햅틱 마스터-슬레이브 로봇 시스템 : 실험적 성능 평가

In this work, 4-DOF ER haptic master is proposed and integrated with a slave robot for minimally invasive surgery(MIS). Using a controllable ER fluid, the haptic master can generate a repulsive force/torque with the 4-DOF motion. For realization of master-slave robot system, the motion command of the haptic master is realized by slave surgery robot. In order to follow the 4-DOF motion of the haptic master, novel mechanism of slave surgery robot with gimbal joint is devised. Accordingly, the haptic master-slave robot system is established by incorporating the slave robot with the haptic master device in which the desired repulsive force/torque and position are transferred to each other via wireless communications. In order to obtain the desired force/torque and position trajectories, tracking controllers for haptic master and slave robot are designed and implemented, respectively. It has been demonstrated that the desired effective torque tracking control performance is well achieved using the proposed haptic master-slave robot system.

1A2-B12 手術支援システムの安全性向上のための危険検知・自動回避システムの開発(医療ロボティクス・メカトロニクス(2))

This study aims at developing an autonomous risk detection system to improve the safety of robotic surgery. Conventional robotic laparoscopic surgery is conducted using a master-slave robotic system, which relies on communication stability between the master and slave sites. Communication delay or errors may lead to unwanted motions of the slave manipulators, thus autonomous risk detection methods robust to communication problems are desired. Hence, we propose to estimate the mechanical properties of the organs being manipulated by the slave manipulators using force sensors in order to detect the risk of organ damage. To validate this concept, we developed a system to autonomously detect the perforation risk of a membrane-like object by demonstration-based learning. We performed experiments to evaluate the developed system, and the results showed that the developed system successfully detected the risk of perforation.

2A1-L01 単孔式内視鏡手術のためのマスタ・スレーブロボットシステムに用いる湾曲式手術器具の評価(手術支援ロボティクス・メカトロニクス(1))

Single-incision laparoscopic surgery (SILS) is less invasive than conventional laparoscopic surgery which requires several incisions to perform surgery. However, burden of an operator performing it increases for some reasons such as the limitation of operating ranges, interference between surgical instruments and a laparoscope and requirement of practice. To solve these problems, we developed a master-slave robot system which can conduct as if the operator was performing conventional laparoscopic surgery. We confirmed that our system would reduce the burden of surgeon in SILS by conducting simulation experiments. In this paper, in order to evaluate the proposed system with the real machine, we designed and made two kinds of flexing instruments, and we evaluated the instruments through real experiments.

An ER Haptic Master-Slave Robot System for the Minimally Invasive Surgery

In this research, a slave robot is proposed and integrated with an electrorheological (ER) haptic master for minimally invasive surgery (MIS). A novel mechanism of the slave robot with a gimbal joint is developed to realize 4-DOF motions. The proposed slave robot consists of two arms, gimbal joint and fixed bar. The haptic master can generate a repulsive force as well as position motion for the slave robot. The manufactured slave robot and haptic master are remotely connected with each other via TCP/IP communications. Both repulsive force and position tracking control are evaluated in experiment.