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1 – 10 of over 98000Qi Jiang, Jihua Li and Danish Masood
With the increasing development of the surgical robots, the opto-mechatronic technologies are more potential in the robotics system optimization. The optic signal plays an…
Abstract
Purpose
With the increasing development of the surgical robots, the opto-mechatronic technologies are more potential in the robotics system optimization. The optic signal plays an important role in opto-mechatronic systems. This paper aims to present a review of the research status on fiber-optic-based force and shape sensors in surgical robots.
Design/methodology/approach
Advances of fiber-optic-based force and shape sensing techniques in the past 20 years are investigated and summarized according to different surgical requirement and technical characteristics. The research status analysis and development prospects are discussed.
Findings
Compared with traditional electrical signal conduction, the phototransduction provides higher speed transmission, lower signal loss and the immunity to electromagnetic interference in robot perception. Most importantly, more and more advanced optic-based sensing technologies are applied to medical robots in the past two decades because the prominence is magnetic resonance imaging compatibility. For medical robots especially, fiber-optic sensing technologies can improve working security, manipulating accuracy and provide force and shape feedback to surgeon.
Originality/value
This is a new perspective. This paper mainly researches the application of optical fiber sensor according to different surgeries which is beneficial to learn the great potential of optical fiber sensor in surgical robots. By enumerating the research progress of medical robots in optimization design, multimode sensing and advanced materials, the development tendency of fiber-optic-based force and shape sensing technologies in surgical robots is prospected.
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Xuefeng Zhang, Yulong Zhao and Xuelei Zhang
The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.
Abstract
Purpose
The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.
Design/methodology/approach
The sensor array consists of a sandwich structure. Sensing elements are distributed discretely in the sensor. Each sensing element has two electrodes and a piece of conductive rubber with piezoresistive property. The electrodes, as well as the conductive trace for signal transmission, are printed on the substrate layer by the screen printing technique. A scanning circuit based on zero potential method and an experimental set‐up based on balance to characterize the sensor array are designed and implemented in the test of the sensor array.
Findings
Experimental results verify the validity of the sensor array in measuring the vertical tactile force between the sensing elements and the object.
Research limitations/implications
In this paper, all the sensors are tested without calibration procedures and the procedure of the dynamic test is implemented by manual operation.
Practical implications
The sensor array could be applied to measure the plantar force for gait detection in clinical applications.
Originality/value
The paper presents a tactile force sensor array with discrete sensing elements to essentially restrict the cross‐talk among sensing elements. This paper will provide many practical details that can help others in the field.
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Zhou Gaofeng, Zhao Yulong and Jiang Zhuangde
The flexibly thin film grid pressure sensor is mainly used to detect the interface pressure distribution between touching objects. Aim at larger measurement error, the strip…
Abstract
Purpose
The flexibly thin film grid pressure sensor is mainly used to detect the interface pressure distribution between touching objects. Aim at larger measurement error, the strip double sensing layer pressure sensor are designed and fabricated and tested.
Design/methodology/approach
Defects and characteristic of the flexibly thin film grid pressure sensor based on piezoresistive effect are analyzed and pointed out in this paper. After comparison of four sensors, the strip double sensing layer pressure sensor was thought to be best.
Findings
Experiment shows that the strip double sensing layer pressure sensor could eliminate the measurement error basically and illustrates the validity of measuring the interface pressure distribution between area touching objects.
Research limitations/implications
In this paper, only the strip double sensing layer pressure sensor was used to verify the validity of measuring the static interface pressure distribution between peach and platform. But there also exists some problems such as the adhering reliability of electrode and the unevenness of sensing layer. These problems could be overcome in the future research if the fabricating procedure and ingredient of material could be adjusted correctly.
Practical implications
The strip double sensing layer pressure sensor could be applied to detect the static interface pressure distribution such as peach pressure distribution. For dynamic measurement, this research needs to be done further.
Originality/value
Strip double sensing layer pressure sensor with simple “interlayer” structure and with low manufacture cost is presented to basically eliminate the measurement error of interface pressure distribution of original sensor.
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Kang Min, Fenglei Ni and Hong Liu
The purpose of the paper is to propose an efficient and accurate force/torque (F/T) sensing method for the robotic wrist-mounted six-dimensional F/T sensor based on an excitation…
Abstract
Purpose
The purpose of the paper is to propose an efficient and accurate force/torque (F/T) sensing method for the robotic wrist-mounted six-dimensional F/T sensor based on an excitation trajectory.
Design/methodology/approach
This paper presents an efficient and accurate F/T sensing method based on an excitation trajectory. First, the dynamic identification model is established by comprehensively considering inertial forces/torques, sensor zero-drift values, robot base inclination errors and forces/torques caused by load gravity. Therefore, the sensing accuracy is improved. Then, the excitation trajectory with optimized poses is used for robot following and data acquisition. The data acquisition is not limited by poses and its time can be significantly shortened. Finally, the least squares method is used to identify parameters and sense contact forces/torques.
Findings
Experiments have been carried out on the self-developed robot manipulator. The results strongly demonstrate that the proposed approach is more efficient and accurate than the existing widely-adopted method. Furthermore, the data acquisition time can be shortened from more than 60 s to 3 s/20 s. Thus, the proposed approach is effective and suitable for fast-paced industrial applications.
Originality/value
The main contributions of this paper are as follows: the dynamic identification model is established by comprehensively considering inertial forces/torques, sensor zero-drift values, robot base inclination errors and forces/torques caused by load gravity; and the excitation trajectory with optimized poses is used for robot following and data acquisition.
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An extensive survey of over 300 reports worldwide shows that the state‐of‐the‐art in tactile sensing — defined as continuously variable touch sensing over an area where there is…
Abstract
An extensive survey of over 300 reports worldwide shows that the state‐of‐the‐art in tactile sensing — defined as continuously variable touch sensing over an area where there is special resolution — is primitive. Only now is a new level of sophistication beginning to appear. However, for industrial systems the simplest may prove to be the most reliable.
Kun Li, Bo Pan, Juncheng Zhan, Wenpeng Gao, Yili Fu and Shuguo Wang
This paper aims to develop a novel miniature 3-axis force sensor which can detect the interaction forces during tissue palpation in MIS (minimally invasive surgery). MIS offers…
Abstract
Purpose
This paper aims to develop a novel miniature 3-axis force sensor which can detect the interaction forces during tissue palpation in MIS (minimally invasive surgery). MIS offers many significant merits compared with traditional open surgery, the wound to the patients and the postoperative pains are alleviated and reduced dramatically. However, the inherent drawback due to lack of force feedback still exists while conducting some operation procedures. For example, tissue palpation performed easily during open surgery could not be realized in an MIS manner.
Design/methodology/approach
The force sensor is based on the resistive-based sensing method that utilizes strain gauges to measure the strain when the external loads are acting on the tip of the sensor. A novel flexible tripod structure with bending and compression deformations is designed to discriminate the magnitudes and directions of the three orthogonal force components. A linear characteristic matrix is derived to disclose the relationship between the sensitivity and the geometric parameters of the structure, and a straightforward geometric parameterized optimization method considering the sensitivity isotropy is proposed to provide the sensor structure with high sensitivity and adequate stiffness.
Findings
The sensor prototype can perform force measurement with sensing ranges of ± 3.0 N in axial direction and ± 1.5 N in radial direction, and the resolutions are 5 per cent and 1 per cent, respectively. It is concluded that this force sensor is compatible with MIS instruments and the ex-vivo experiment shows that the sensor can be used to perform tissue palpation during MIS procedures.
Originality/value
This paper is intended to address the significant role of force sensing and force feedback during MIS operations, and presents a new application of the resistive-based sensing method in MIS. A tripod structure is designed and a straightforward optimization method considering the sensitivity isotropy of the sensor is proposed to determine geometric parameters suited for the given external loads.
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Abstract
Purpose
Existing robot-assisted minimally invasive surgery (RMIS) system lacks of force feedback, and it cannot provide the surgeon with interaction forces between the surgical instruments and patient’s tissues. This paper aims to restore force sensation for the RMIS system and evaluate effect of force sensing in a master-slave manner.
Design/methodology/approach
This paper presents a four-DOF surgical instrument with modular joints and six-axis force sensing capability and proposes an incremental position mode master–slave control strategy based on separated position and orientation to reflect motion of the end of master manipulator to the end of surgical instrument. Ex-vivo experiments including tissue palpation and blunt dissection are conducted to verify the effect of force sensing for the surgical instrument. An experiment of trajectory tracking is carried out to test precision of the control strategy.
Findings
Results of trajectory tracking experiment show that this control strategy can precisely reflect the hand motion of the operator, and the results of the ex-vivo experiments including tissue palpation and blunt dissection illustrate that this surgical instrument can measure the six-axis interaction forces successfully for the RMIS.
Originality/value
This paper addresses the important role of force sensing and force feedback in RMIS, clarifies the feasibility to apply this instrument prototype in RMIS for force sensing and provides technical support of force feedback for further clinical application.
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Haifeng Fang, Yangyang Wei and Shuo Dong
Tactile sensation is an important sensory function for robots in contact with the external environment. To better acquire tactile information about objects, this paper aims to…
Abstract
Purpose
Tactile sensation is an important sensory function for robots in contact with the external environment. To better acquire tactile information about objects, this paper aims to propose a three-layer structure of the interdigital flexible tactile sensor.
Design/methodology/approach
The sensor consists of a bottom electrode layer, a middle pressure-sensitive layer and a top indenter layer. First, the pressure sensitive material, structure design, fabrication process and circuit design of the sensor are introduced. Then, the calibration and performance test of the designed sensor is carried out. Four functions are used to fit and calibrate the relationship between the output voltage of the sensor and the contact force. Finally, the contact force sensing test of different weight objects and the flexible test of the sensor are carried out.
Findings
The performance test results show that the sensitivity of the sensor is 0.93 V/N when it is loaded with 0–3 N and 0.23 V/N when it is loaded with 3–5 N. It shows good repeatability, and the cross-interference between the sensing units is generally low. The contact force sensing test results of different weight objects show that the proposed sensor performs well in contact force. Each part of the sensor is a flexible material, allowing the sensor to achieve bending deformation, so that the sensor can better perceive the contact signs of the grasped object.
Practical implications
The sensor can paste the surface of the paper robot’s gripper to measure the contact force of the grasping object and estimate the contour of the object.
Originality/value
In this paper, a three-layer interdigital flexible tactile sensor is proposed, and the structural parameters of the interdigital electrode are designed to improve the sensitivity and response speed of the sensor. The indenter with three shapes of the prism, square cylinder and hemisphere is preliminarily designed and the prism indenter with better conduction force is selected through finite element analysis, which can concentrate the external force in the sensing area to improve the sensitivity. The sensor designed in this paper can realize the measurement of contact force, which provides a certain reference for the field of robot tactile.
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When designing hardware and algorithms for robotic manipulation and grasping, sensory information is typically needed to control the grasping process. This paper presents an…
Abstract
Purpose
When designing hardware and algorithms for robotic manipulation and grasping, sensory information is typically needed to control the grasping process. This paper presents an overview of the major grasping and manipulation approaches and the more common hardware used to obtain the necessary sensory information.
Design/methodology/approach
This paper presents an overview of tactile sensing in intelligent robotic manipulation. The history, the common issues, and applications are reviewed. Sensor performance is briefly discussed and compared to the human tactile sense. Advantages and disadvantages of the most common sensor approaches are discussed. Some examples are given of sensors that are widely available as of today. Eventually, some examples of the state‐of‐the‐art in tactile sensing application are presented.
Findings
Although many sensor technologies and strong theoretical models have been developed, there is still much left to be done in intelligent grasping and manipulation. This is partly due to the youth of the field and the complex nature of safe control in uncertain environments. Even though there are impressive results when it comes to specific examples of advanced manipulation, there seems to be room for great improvements of hardware and especially algorithms when it comes to more generic everyday domestic tasks.
Originality/value
This paper presents a review of sensor hardware while also giving a glimpse of the major topics in grasping and manipulation. While better hardware of course is desirable, the major challenges seem to lie in the development and application of grasping and manipulation algorithms.
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Abstract
Purpose
This study aims to introduce the DoraHand, and the basic capability and performance have been verified in this paper. Besides the idea of sharing modular design and sensor design, the authors want to deliver an affordable and practical dexterous hand to the research area to contribute to the robotic manipulation area.
Design/methodology/approach
This paper introduced the DoraHand, a novel scalable and practical modular dexterous hand, which, adopting modular finger and palm design, fully actuated joint and tactile sensors, can improve the dexterity for robotic manipulation and lower the complexity of maintenance. A series of experiments are delivered to verify the performance of the hand and sensor module.
Findings
The parameters of the DoraHand are verified and suitable for the research of robotics manipulation area, the sensing capability has been tested with the static experiment and the slip prediction algorithm. And, the advantage of modular design and extensible interface have been verified by the real application.
Research limitations/implications
The authors continue improving the DoraHand and extend it to more different applications. The authors want to make the DoraHand as a basic research platform in the robotic manipulation area.
Practical implications
The DoraHand has been sent to more than ten different research institutes for different research applications. The authors continue working on this hand for better performance, easier usage and more affordability.
Social implications
This kind of dexterous hand can help researchers get rid of complex physical issues and pay more attention to the algorithm part; it can help to make robotic manipulation work more popular.
Originality/value
The key design in the DoraHand is the modular finger and sensing module. With the special design in mechanical and electrical parts, the authors build reliable hardware and can support the diversity requirement in the robotic manipulation area. The hand with tactile sensing capability can be used in more research and applications with its extensibility.
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