Master-slave Robotic System Research Articles

Output based bilateral adaptive control of partially known robotic systems

This paper describes the design and implementation of a robust adaptive bilateral observer based control to solve the trajectory tracking problem for a class of master–slave robotic systems. The output-based bilateral control uses an adaptive observer to estimate the force and the unmeasurable velocity state considering only the master–slave system order as well as the position measurements. The stability of the observer and controller is simultaneously proved via the second method of Lyapunov. A set of experimental tests proved the performance of the presented algorithm for a manipulation task in a bilateral teleoperated system based on two delta robots.

Design, Modeling, and Evaluation of a Compact and Lightweight Needle End-effector with Simple Force-feedback Implementation for Robotic CT-guided Needle Interventions

We present a compact and lightweight two degrees-of-freedom (DOF) needle end-effector to be applied to a teleoperated needle interventional robotic system. The suggested needle end-effector is computerized tomography (CT)-compatible and easy to sterilize. Because the proposed needle end-effector can be attached to a robotic manipulator, the needle can translate into and rotate in the human body. In addition, a 1-axis load cell is attached to the needle end-effector to measure the longitudinal force applied to the needle. With this force measurement, force-feedback ability has been implemented in the entire master-slave robotic system. Basic performance tests of repeatability and maximum insertion force were performed. Several force-feedback experiments to determine free space response and contact response, as well as a discrimination test, were conducted. Through this verification process, the suggested needle end-effector was found to have potential for application in real environments that require robotic CT-guided needle interventions.

Advantage of Steerable Catheter and Haptic Feedback for a 5-DOF Vascular Intervention Robot System

Vascular intervention involves inserting a catheter and guidewire into blood vessels to diagnose and treat a disease in an X-ray environment. In this conventional vascular intervention procedure, the doctor is exposed to considerable radiation. To reduce the exposure, we developed a master–slave robot system. A steerable catheter is employed to shorten the task-time and reduce the contact force applied to the vessel walls during catheter insertion. The steerable catheter helps to select a vascular branch; thus, the radiation exposure time for patients is reduced, and perforation in the patient’s vessel is prevented. Additionally, the robot system employs a haptic function to replicate the physician’s tactile sensing in vascular intervention. In this study, the effectiveness of the steering catheter and haptic function was demonstrated experimentally in comparison with a conventional catheter.

Control of master slave robotics system using optimal control schemes

This paper presents application of Proportional Integral Derivative (PID) and Non-linear PID (NPID) controllers to optimally operate the master slave robotic system. Teleoperation is widely used in different applications, such as surgical robots, underwater vehicles, power lines and even in space. However there are problems in teleoperation systems that may lead to degradation in system performance or even to system instability. This paper presents new and optimal control schemes that can satisfy the required performance, insure system stability and achieve zero tracking error in presence of constant time delay and model approximation. Optimal gains are obtained using the Genetic Algorithm in a systematic way that could be applied to other control schemes. The results proved the effectiveness of both control schemes than the previously applied scheme. The NPID control scheme has better performance, provided position tracking and achieved zero tracking error in less settling time than PID one. The results obtained by the presented control schemes are evaluated based on comparing the system performance using three different types of controllers which are P-like, Genetic PID and Genetic NPID. The study was carried out using MATLAB/SIMULINK 2017a.

A Soft Master-Slave Robot Mimicking Octopus Arm Structure Using Thin Artificial Muscles and Wire Encoders

An octopus arm with a flexible structure and no rigid skeleton shows a high degree of freedom and flexibility. These excellent features are suitable for working in an environment having fragile and unknown-shaped objects. Therefore, a soft robot arm resembling an octopus arm can be useful as a harvesting machine without damaging crops in the agricultural field, as a rehabilitation apparatus in the welfare field, as a safe surgery tool in the medical field, and so on. Unlike industrial robots, to consider the applications of the soft robot arm, the instructions for it relating to a task cannot in many cases be given as a numerical value, and the motion according to an operator’s sense and intent is useful. This paper describes the design and feedback control of a soft master-slave robot system. The system is configured with two soft rubber machines; one is a slave machine that is the soft robot arm mimicking the muscle arrangement of the octopus arm by pneumatic artificial muscles, and the other is a master machine that gives the target motion to the slave machine. Both are configured with soft materials. The slave machine has an actuating part and a sensing part, it can perform bending and torsional motions, and these motions are estimated by the sensing part with threads that connect to wire encoders. The master machine is almost the same configuration, but it has no actuating part. The slave machine is driven according to the deformation of the master machine. We confirmed experimentally that the slave machine followed the master machine that was deformed by an operator.

Safety Control Method of Robot-Assisted Cataract Surgery with Virtual Fixture and Virtual Force Feedback

Surgery is an effective means of treating cataracts and restoring vision. However, cataract surgery rate (CSR) in developing countries and regions is relatively low due to the lack of experienced high-level surgeons. In this paper, to reduce the reliance of surgery on physician experience and thereby increase CSR, a master-slave robotic system and safety control strategies with a virtual fixture and virtual force feedback are proposed to assist cataract surgery. First, the surgery is divided into four different stages with different robot control modes. Secondly, the virtual constraint area with virtual spring model in the operating stage is established, so that the doctor can distinguish the operation area where the end of the surgical instrument is located by feedback force. Thirdly, safety control algorithm guarantees that the surgical instrument strictly moves around the surgical incision point, which is regarded as a remote centre of motion, so that the cornea outside the incision point is not injured. Finally, the experimental results show that the proposed safety control strategy allows the robotic system to perform the procedure safely.

12.4 THE BODILY SELF IN PSYCHOSIS: SENSORIMOTOR INDUCTION OF AUDITORY MISATTRIBUTION IN PSYCHOSIS IS LINKED TO NEURAL DISCONNECTIVITY

Abstract Background Psychosis is often depicted as a disruption of the self-model. Patients suffering from psychosis report many symptoms relating to deficiencies in the minimal self, including loss of the sense of control over their actions (Sense of Agency) as well as numerous disturbances of body representation (e.g. Body Ownership). Positive symptoms of psychosis such as passivity symptoms and auditory hallucinations (termed first-rank symptoms) are characterized by a diminished demarcation of self-other boundaries, causing misattribution of self-generated actions to external sources. It has been suggested that this deficiency in self-monitoring in schizophrenia is due to abnormal sensorimotor prediction mechanisms, causing a loss of agency for actions and thoughts. While the neurobiological underpinnings of schizophrenia are yet unclear, many studies have reported aberrant neural connectivity in schizophrenia patients which may impact sensorimotor prediction and integration. Methods Recently, we have shown that introducing sensorimotor conflict (SMC) can induce psychosis like symptoms in healthy patients. Employing a master-slave robotic system we induced a conflict by introducing a delay between the participants’ movements and the haptic feedback. The SMC caused a feeling of a Presence (FoP) which is a first rank symptom of psychosis. The FoP is also found in neurological patients with lesions in cortical regions of the temporoparietal cortex, insular cortex and fronto-parietal cortex related to abnormal bodily self-representation. Here, we tested if SMC may cause misattribution of auditory stimuli and if this is related to neural connectivity. We tested first episode psychosis patients (N=31) with and without first rank symptoms (related to the sense of control over actions and thoughts) as well as healthy participants (N=20) on an auditory attribution task while inducing conflict with the master-slave robot. Results We found that when a SMC was introduced patients with first rank symptoms showed a decrease in their ability to judge if the auditory stimuli were in their own voice or the voice of another person. Resting state functional connectivity analysis indicated that the first rank patients had reduced connectivity in the network related to the SMC, but not in other control regions. Furthermore, the reduced functional connectivity correlated with the rates of auditory misattribution. Conclusions Our results show that induction of SMC can cause auditory misattributions, and that this is related to reduced cortical communication in regions related to sensorimotor body representation. These findings connect two influential theories of psychosis linking cognitive theories of sensorimotor prediction error in schizophrenia with systems level theories of neural disconnectivity. Understanding these neurocognitive mechanisms underlying the disruption of the self-model in psychosis may allow novel approaches in early diagnosis and treatment of these conditions.

Design of a Miniature Series Elastic Actuator for Bilateral Teleoperations Requiring Accurate Torque Sensing and Control

Compared with stiff actuators, series elastic actuators (SEAs) can render more accurate output torque and stiffness. Hence, SEAs are suitable for robots that need to interact safely with human or properly with the actual or virtual environment. Many existing rotary SEAs are bulky and not suitable for multiple-degree-of-freedom (DoF) applications. To explore the merits of SEAs in bilateral teleoperations that often require multiple-DoF force feedback, this letter presents a miniature rotary SEA. By using a specifically designed planar spring, the size of the SEA can be minimized while the output torque and stiffness can still be accurately controlled. Dynamic modeling and impedance control experiments show that the torque and stiffness rendering results are better than those of existing SEAs. A master-slave robot system using the proposed SEA demonstrates that both stiff and soft remote environments can be virtually realized. We expect that this miniature SEA can serve as an alternative actuator for robotic teleoperations requiring accurate torque sensing and control.

A novel robotic system for vascular intervention: principles, performances, and applications.

This paper describes the design, principles, performances, and applications of a novel image-guided master-slave robotic system for vascular intervention (VI), including the performance evaluation and in vivo trials. Based on the peer-to-peer (P2P) remote communication system, the kinetics analysis, the sliding-mode neural network self-adaptive control model and the feedback system, this new robotic system can accomplish in real time a number of VI operations, including guidewire translation and rotation, balloon catheter translation, and contrast agent injection. The master-slave design prevents surgeons from being exposed to X-ray radiation, which means that they are not required to wear a heavy lead suit. We also conducted a performance evaluation of the new system, which assessed the speed, position tracking, and accuracy, as well as in vivo swine trials. The speed and position tracking effects are really good, which contribute to the high level of performance in terms of the translational (error ≤ 0.45%) and rotational (error ≤ 2.6°) accuracy. In addition, the accuracy of the contrast agent injection is less than 0.2ml. The robotic system successfully performed both the stent revascularization of an arteria carotis and four in vivo trials. The haptic feedback data correspond with the robotic-assisted procedure, and peaks and troughs of data occur regularly. By means of the performance evaluation and four successful in vivo trials, the feasibility and efficiency of the new robotic system are validated, which should prove helpful for further research.

Development of a virtual reality training simulator for robot-assisted dura mater suturing in endonasal neurosurgery

Manual suturing of dura mater after endonasal tumor resection is a difficult task in neurosurgery due to the constrained workspace and narrow field of view, requiring hours of training. Master-slave robotic systems are being developed to support such a complex task; however, the neurosurgeons still need to adapt themselves to the new robotic systems. We propose the development of a virtual reality simulation for surgical training of robot-assisted dura mater suturing. The simulator is also useful to test the robot inside a safe environment without risking the physical prototype.

Using Brain Activation to Evaluate Arrangements Aiding Hand-Eye Coordination in Surgical Robot Systems.

To realize intuitive, minimally invasive surgery, surgical robots are often controlled using master-slave systems. However, the surgical robot's structure often differs from that of the human body, so the arrangement between the monitor and master must reflect this physical difference. In this study, we validate the feasibility of an embodiment evaluation method that determines the arrangement between the monitor and master. In our constructed cognitive model, the brain's intraparietal sulcus activates significantly when somatic and visual feedback match. Using this model, we validate a cognitively appropriate arrangement between the monitor and master. In experiments, we measure participants' brain activation using an imaging device as they control the virtual surgical simulator. Two experiments are carried out that vary the monitor and hand positions. There are two common arrangements of the monitor and master at the brain activation's peak: One is placing the monitor behind the master, so the user feels that the system is an extension of his arms into the monitor; the other arranges the monitor in front of the master, so the user feels the correspondence between his own arm and the virtual arm in the monitor. From these results, we conclude that the arrangement between the monitor and master impacts embodiment, enabling the participant to feel apparent posture matches in master-slave surgical robot systems.

Research and Realization of a Master-Slave Robotic System for Retinal Vascular Bypass Surgery

Retinal surgery continues to be one of the most technical demanding surgeries for its high manipulation accuracy requirement, small and constrained workspace, and delicate retinal tissue. Robotic systems have the potential to enhance and expand the capabilities of surgeons during retinal surgery. Thus, focusing on retinal vessel bypass surgery, a master-slave robot system is developed in this paper. This robotic system is designed based on characteristics of retinal vascular bypass surgery and analysis of the surgical workspace in eyeball. A novel end-effector of two degrees of freedom is designed and a novel remote center of motion mechanism is adopted in the robot structure. The kinematics and the mapping relationship are then established, the gravity compensation control strategy and the hand tremor elimination algorithm are applied to achieve the high motion accuracy. The experiments on an artificial eyeball and an in vitro porcine eye are conducted, verifying the feasibility of this system.

Image-Guided Dual Master–Slave Robotic System for Maxillary Sinus Surgery

The pathway to the maxillary sinus is anatomically curved and narrow. Thus, the conventional approach using a straight endoscope and surgical tools is difficult to diagnose and treat some blind regions of the maxillary sinus through the nostrils. Such cases are usually dealt with by an approach with an external incision that causes large invasive surgery. In order to approach the blind regions without any external incision, a new bendable device and an image-guided robotic approach for the maxillary sinus surgery are required. This work reports design, development, and validation of an image-guided dual master–slave robotic system for the maxillary sinus surgery. Initially, specifications of the robotic system for sinus surgery are decided by analysis of the anatomical structure of the sinus. A method for determining the design parameters of continuum type salve robot is also presented. Based on the specifications and the design parameter determining method, a compact design of bendable dual slave robotic system for inspection and biopsy operation of the maxillary sinus area is devised and workspace analysis for verifying the robot design is conducted. The performance of the dual master–slave system equipped with flexible devices is validated through several phantom tests. The results suggest that bendable end-effectors and navigation software are useful to navigate and treat blind regions inside general sinus areas as well as the maxillary sinus.

Random Weighting, Strong Tracking, and Unscented Kalman Filter for Soft Tissue Characterization.

This paper presents a new nonlinear filtering method based on the Hunt-Crossley model for online nonlinear soft tissue characterization. This method overcomes the problem of performance degradation in the unscented Kalman filter due to contact model error. It adopts the concept of Mahalanobis distance to identify contact model error, and further incorporates a scaling factor in predicted state covariance to compensate identified model error. This scaling factor is determined according to the principle of innovation orthogonality to avoid the cumbersome computation of Jacobian matrix, where the random weighting concept is adopted to improve the estimation accuracy of innovation covariance. A master-slave robotic indentation system is developed to validate the performance of the proposed method. Simulation and experimental results as well as comparison analyses demonstrate that the efficacy of the proposed method for online characterization of soft tissue parameters in the presence of contact model error.

A Study of Accuracy and Time Delay for Bilateral Master-Slave Industrial Robotic Arm Manipulator System

Bilateral master-slave industrial robotic arm manipulator system is an advanced technology used to help human to interact with environments that are unreachable to human, due to its remoteness or perilous. The system has been used in different areas such as tele-surgery, autonomous tele-operation for sea and space operation and handling explosive or high radiation operation fields. It is beneficial both for science and society. Remarkably, the system is not common and generally used in Malaysia. Likewise, the number of research conducted that focused about this technology in our country manufacturing industry are not yet discovered and existent. The implementation of this bilateral manipulator system in an industrial robot could be useful for industrial imminent and development over our country and people, specifically for production yield size and human operative. Hence, the study of bilateral robotic arm manipulator system in an industrial robot and analyzation of its performance and time delay in 3 differ controllers will be discussed to attest the efficiency and its effectiveness on the said design system. The experiment conducted was on KUKA youBot arm in V-Rep simulation with three different controllers (P, PD, PID).

Method for Latency Measurement of Visual Feedback-Based Master–Slave Minimally Invasive Surgical Robot

To measure the latency between human motion stimulation and stereo image display response in a visual feedback-based minimally invasive surgical (MIS) robotic system, a method was proposed by comparing the orientations of input and output events through image-processing technology. This method used a black bar to keep pace with the measured joint rotating at a number of speeds. During tests, an external camera was placed in front of the apparatus with a proper visual field, so that it can simultaneously view orientations of both bars fixed on the corresponding joints. After quantitatively analyzing the accuracy of the proposed measurement method, the method was applied to a visual feedback-based master–slave robotic system with two-degrees-of-freedom. Experimental results show that the latency of the overall system was approximately 250 ms, and the opposite clearance of the measured joint was in the range of 1.7°–1.9°.

Design of a new haptic device and experiments in minimally invasive surgical robot

In this paper, we designed a 8 degrees of freedom (DOFs) haptic device for applications in minimally invasive surgical robot. The device can provide three translational, three rotational and a grasping motion and force feedback capability. It is composed of three parts, including an arm mechanism, a redundant wrist mechanism and a grasper mechanism. The kinematics and gravity compensation algorithms are also detailed in the paper. In addition, the haptic device and a slave surgical robot for minimally invasive surgery (MIS) developed by our lab are integrated as a master-slave surgical robotic system in this paper. In the master-slave robotic system, a new control system is designed to realize real-time mater-slave control based on EtherCAT bus technology. Experiments show that the haptic device can effectively compensate gravity at any position in its workspace and successfully realize master-slave operation by the control method, which prove the haptic device designed in this paper can be used as a master manipulator to control the surgical robot.

Master-slave robotic system for needle indentation and insertion

Bilateral control of a master-slave robotic system is a challenging issue in robotic-assisted minimally invasive surgery. It requires the knowledge on contact interaction between a surgical (slave) robot and soft tissues. This paper presents a master-slave robotic system for needle indentation and insertion. This master-slave robotic system is able to characterize the contact interaction between the robotic needle and soft tissues. A bilateral controller is implemented using a linear motor for robotic needle indentation and insertion. A new nonlinear state observer is developed to online monitor the contact interaction with soft tissues. Experimental results demonstrate the efficacy of the proposed master-slave robotic system for robotic needle indentation and needle insertion.

Shadow and Mirror Mode Bilateral Control for a Tele-Operated Robot System

This paper proposes the development of haptic robot system for rehabilitation exercises. Recently, haptic communication is widely applied in a robot system for sensing the force between robot and human operator. The bilateral control which consists of master and slave robot is used to transfer and receive action/ reaction force and position information. In this paper, the controlling of robot has been designed by considering the specification requirements of user. This master-slave robot system can be controlled by two different approaches: 1) by using the shadow mode and 2) by using the mirror mode. In the force control designed, such force sensor can use to measure the external force. It is shown that the reaction force response can be controlled. However, the problem of sensor noise and bandwidth are deteriorated the performance not only at the master or slave side but also at the whole control system. Thus, disturbance observer (DOB) has been proposed and used instead of force sensor for improve the performance and robustness of the whole system. In this study, the shadow and mirror mode of bilateral control is used with the master-slave robot for rehabilitation exercise. On the shadow mode slave robot is controlled according to the master robot like a shadow while mirror mode, slave robot has moved in the opposite direction like a reflection image. The results of each mode are represented in an experimental result. By using the proposed robot system, it is possible to apply in the rehabilitation process.

Validation of a CT-guided intervention robot for biopsy and radiofrequency ablation: experimental study with an abdominal phantom.

We aimed to evaluate the accuracy of a needle-placement robot for biopsy and radiofrequency ablation on an abdominal phantom. A master-slave robotic system has been developed that includes a needle-path planning system and a needle-inserting robot arm with computed tomography (CT) and CT fluoroscopy guidance. For evaluation of its accuracy in needle placement, a commercially available abdominal phantom (Model 057A; CIRS Inc.) was used. The liver part of the phantom contains multiple spherical simulated tumors of three different size spheres. Various needle insertion trials were performed in the transverse plane and caudocranial plane two nodule sizes (10 mm and 20 mm in diameter) to test the reliability of this robot. To assess accuracy, a CT scan was performed after each trial with the needle in situ. The overall error was 2 mm (0-2.6 mm), which was calculated as the distance from the planned trajectory before insertion to the actual needle trajectory after insertion. The standard deviations of the insertions on two nodules (10 mm and 20 mm in diameter) were 0.5 mm and 0.2 mm, respectively. The CT-compatible needle placement robot for biopsy and radiofrequency ablation shows relatively acceptable accuracy and could be used for radiofrequency ablation of nodules ≥10 mm under CT fluoroscopy guidance.