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TakoBot CAD view with spring coefficient k. Equations (8) and (9) include 2n angles of the n universal joints θ xi and θ yi ,(i=1, ⋯, n). X and Y components in (8) and (9) are meaningful since the universal joints do not rotate about the z-axis, which means 2n equations are used to derive the 2n variables. Therefore we can derive θ xi and θ yi , (i=1, ⋯, n) for a given set of wire tensions f a , f b , f c , f d
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This paper presents cable-driven bio-inspired continuum robot with variable backbone hardness and with mounted compliant universal joints. Proposed continuum robot has nine segments and each one of which has two rotary joints. Kinetics, kinematics and design concerns are very challenging in continuum robots. So, in this research, we will present a...
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A bstract
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Citations
... For instance, the silicone-based flexible robotic arm driven by a shape memory alloy (SMA) coil, as designed by Haoyang et al. [12], experiences noticeable deformation due to stress concentration during high-load tasks, resulting in task failure. The cable-driven bio-inspired continuum robot designed by Azamat Yeshmukhametov [13], uses a multi-joint rigid skeletal structure, which enhances load-bearing capacity compared to purely flexible robotic arms [14]; however, this design shows limited performance in adapting to complex terrains and achieving non-damaging contact. Therefore, neither purely flexible nor rigid designs can fully meet the demands of complex tasks [15]. ...
Given the growing complexity of underwater operation tasks, particularly in confined spaces, turbulent environments, and dynamic object manipulation, the limitations of traditional rigid robotic arms are becoming ever more evident. To tackle these challenges, this paper proposes the development of a soft robotic arm modeled after octopus tentacles, incorporating biomimetic suckers. To tackle these challenges, this paper proposes the development of a soft robotic arm modeled after octopus tentacles, incorporating biomimetic suckers. By imitating the functional structure and suction cups of an octopus arm, a soft arm with a dual-segment continuous structure and eight-wire drive control is designed, integrating a flexible suction cup at the distal segment. A three-dimensional, dual-segment eight-wire driven segmented constant curvature motion model is developed to enable precise bending and rotational movements. In underwater grasping experiments, the soft robotic arm exhibited enhanced grasping stability, particularly in underwater environments, where it effectively copes with fluid disturbances and the capture of dynamic objects. This substantially increased the reliability and efficiency of underwater operations.
... The driving mechanisms of continuous manipulators are divided into external driving mechanisms, internal driving mechanisms, and hybrid driving mechanisms. Representative examples of external driving mechanisms include the concentric tube manipulator [5], [6], [7] and the cable-driven continuum manipulator [8], [9], [10]. Internal driving mechanisms are exemplified by manipulators driven by air pressure [11] or magnets [12], [13]. ...
The continuum manipulators are the most common wrist joint design in surgical robots. However, there is currently no complete and accurate evaluation system to evaluate the performance of the continuum manipulator. In this paper, a static model-based assessment method is proposed to evaluate the dexterity of continuum manipulator. Compared to conventional approaches, the methodology presented in this paper demonstrates superior accuracy and scientific rigor, contributing to the establishment of a comprehensive framework for the evaluation of the dexterity of continuum manipulators. Firstly, static models for three commonly encountered continuum manipulators are established. Based on the Bernoulli-Euler beam theory, the static models for the cable-driven continuum manipulator and hybrid continuum manipulator are established taking into account the large deformations of the manipulators. Compared with the traditional constant curvature model, the average error is reduced from 0.67% to 0.33%. The static model for the concentric tube manipulator is established by solving differential equations and based on differential element method. The average error is reduced from 3.09% to 0.90%. Subsequently, the effective workspace of the continuum manipulators is defined based on operational requirements. Based on the established static models and the service sphere theory, a more accurate dexterity assessment method is proposed within the effective workspace. Finally, the assessment of the dexterity is conducted for the three types of continuum manipulators. Simulation results indicate that within the effective workspace, the average dexterity is 0.4571 for the cable-driven continuum manipulator, 0.2495 for the hybrid continuum manipulator, and 0.1753 for the concentric tube manipulator. This paper is of paramount significance in refining the comprehensive performance evaluation framework for surgical robots.
... Additionally, as indicated by [38,45,116], continuum arm robots exhibit specific advantages over RLMs. These research works further suggest that at present, there are only a few features, such as payload capacity, agility, controllability, path planning, and positioning, posing challenges to CMs compared to RLMs. ...
... There are two main approaches followed in positioning the joints. Some designs choose to place the joints along the centreline of the backbone, resembling vertebrae [39,116], while others prefer to position them at the periphery or outer surface of a tubularprofiled manipulator design [134,136]. In the latter approach, the tendon guides (eyelets) are fashioned either in the form of welded guide rings radially attached to the joint supports [134,136], or as guide holes (eyelets) created on disks inserted at equal intervals throughout the manipulator. ...
... In the latter approach, the tendon guides (eyelets) are fashioned either in the form of welded guide rings radially attached to the joint supports [134,136], or as guide holes (eyelets) created on disks inserted at equal intervals throughout the manipulator. Conversely, the centreline-based joints method features radially extended flange/disk profiles around each joint, providing eyelets for routing the tendons [39,116,137]. ...
Aerial manipulators have seen a rapid uptake for multiple applications, including inspection tasks and aerial robot–human interaction in building and construction. Whilst single degree of freedom (DoF) and multiple DoF rigid link manipulators (RLMs) have been extensively discussed in the aerial manipulation literature, continuum manipulators (CMs), often referred to as continuum robots (CRs), have not received the same attention. This survey seeks to summarise the existing works on continuum manipulator-based aerial manipulation research and the most prevalent designs of continuous backbone tendon-driven continuum robots (TDCRs) and multi-link backbone TDCRs, thereby providing a structured set of guidelines for fabricating continuum robots for aerial manipulation. With a history spanning over three decades, dominated by medical applications, CRs are now increasingly being used in other domains like industrial machinery and system inspection, also gaining popularity in aerial manipulation. Fuelled by diverse applications and their associated challenges, researchers have proposed a plethora of design solutions, primarily falling within the realms of concentric tube (CT) designs or tendon-driven designs. Leveraging research works published in the past decade, we place emphasis on the preparation of backbones, support structures, tendons, stiffness control, test procedures, and error considerations. We also present our perspectives and recommendations addressing essential design and fabrication aspects of TDCRs in the context of aerial manipulation, and provide valuable guidance for future research and development endeavours in this dynamic field.
... One of the most critical aspects of cable-driven manipulators design is the material of cables themselves. Cables can be made of stainless steel [22], or synthetic fibre, as in the Super Dragon robot [23]. A comparison between the physical properties of these two materials was performed by Horigome and Endo in 2016 [24], who also conducted repetitive bending experiments on synthetic fibre cables in 2018 [25]. ...
... and using (22), (30) reduces to: ...
Robotic manipulators provide advantages in working environments regarding efficiency and safety, which is further increased in the case of elastic joint manipulators, whose mechanical compliance reduces the energy involved in collisions with workers. Cable-driven manipulators are elastic joint manipulators particularly suitable for industrial inspection thanks to the relocation of actuators outside hostile environments, increasing the manipulator payload-to-weight ratio. Recently, synthetic fibre cables are substituting steel cables due to their better-performing mechanical properties, but their visco-elastic behaviour must be compensated in the controller design. The key novelty of this work is using the four elements model, which includes the viscous behaviour, to design a non-linear full-state feedback controller for cable-driven manipulators. Furthermore, the mathematical proof of the closed-loop Lyapunov stability is provided.
... Similar approaches of antagonistic tendon actuation have been presented in more industrial, agricultural or underwater large scale applications [7,[10][11][12][13]. Here, nonmedical applications often allow for larger diameter robot bodies, simplifying actuator integration. ...
... The robot's dimensions of only 9.9 mm diameter but 260 mm length support application in minimally invasive robotic surgery. In contrast to [12], tendons are implemented directly on the motor's rotors and no slippage was observed. As so far actuator unit miniaturization was out of scope in related literature, comparison of system dimensions is difficult. ...
Continuum robots for application in medicine are of high interest in recent research. However, as most systems in literature show complex and large actuator units, setting up such a system can be time consuming, costly and results in a bulky system, unsuitable for the spatial requirements given in surgical scenarios. In this work, a compact, efficient continuum robotic system is presented. A pair of two antagonistic tendons is controlled by a single servo motor instead of single tendon actuation. This way, the actuator footprint is maintained at a minimum size and the method results in a simpler setup. The resulting 260 mm long robot with 9.9 mm diameter achieves a repeatability with an error of maximum 1.8 % of its length. In future work, this work serves as a basis for integration of various sensing modalities in continuum robots and evaluation of control algorithms.
... Its application in intracranial surgery allows for accurate lesion targeting and effective reduction of robotic-arm-induced tissue damage during surgery. Among the different types of continuum robots, the concentric tube robot [6][7][8] and the cable-driven continuum robot [9,10] have emerged as popular research subjects. ...
The compound continuum robot employs both concentric tube components and cable-driven continuum components to achieve its complex motions. Nevertheless, the interaction between these components causes coupling, which inevitably leads to reduced accuracy. Consequently, researchers have been striving to mitigate and compensate for this coupling-induced error in order to enhance the overall performance of the robot. This paper leverages the coupling between the components of the compound continuum robot to accomplish specific surgical procedures. Specifically, the internal concentric tube component is utilized to induce motion in the cable-driven external component, which generates coupled motion under the constraints of the cable. This approach enables the realization of high-precision surgical operations. Specifically, a kinematic model for the proposed robot is established, and an inverse kinematic algorithm is developed. In this inverse kinematic algorithm, the solution of a highly nonlinear system of equations is simplified into the solution of a single nonlinear equation. To demonstrate the effectiveness of the proposed approach, simulations are conducted to evaluate the efficiency of the algorithm. The simulations conducted in this study indicate that the proposed inverse kinematic (IK) algorithm improves computational speed by a significant margin. Specifically, it achieves a speedup of 2.8 × 10³ over the Levenberg–Marquardt (LM) method. In addition, experimental results demonstrate that the coupled-motion system achieves high levels of accuracy. Specifically, the repetitive positioning accuracy is measured to be 0.9 mm, and the tracking accuracy is 1.5 mm. This paper is significant for dealing with the coupling of the compound continuum robot.
... However, it still requires surgeons to control the movement of this robot-assisted bronchoscopy. This kind of serpentine robot [9][10][11][12] has been discussed as a feasible solution for moving inside the bronchi of the lungs. ...
... As described above, efficient path planning for navigating the robotic bronchoscopy inside the bronchial tree is necessary. Several previous researchers [8][9][10][11][12][13][14] have addressed this issue. In this paper, a backward path planning algorithm is proposed, followed by a forward navigation algorithm. ...
The miniature serpentine robot can be applied to NOTES (Natural Orifice Transluminal Endoscopic Surgery). In this paper, a bronchoscopy application is addressed. This paper describes the basic mechanical design and control scheme of this miniature serpentine robotic bronchoscopy. In addition, off-line backward path planning and real-time and in situ forward navigation in this miniature serpentine robot are discussed. The proposed backward-path-planning algorithm utilizes the 3D model of a bronchial tree constructed from the synthetization of medical images such as images from CT (Computed Tomography), MRI (Magnetic Resonance Imaging), or X-ray, to define a series of nodes/events backward from the destination, for example, the lesion, to the original starting point, for example, the oral cavity. Accordingly, forward navigation is designed to make sure this series of nodes/events shall be passed/occur from the origin to the destination. This combination of backward-path planning and forward navigation does not require accurate positioning information of the tip of the miniature serpentine robot, which is where the CMOS bronchoscope is located. Collaboratively, a virtual force is introduced to maintain the tip of the miniature serpentine robot at the center of the bronchi. Results show that this method of path planning and navigation of the miniature serpentine robot for bronchoscopy applications works.
... Continuum robot designs can be classified predominantly by the method of shape control [7]: multi-backbone designs [8], tendon-actuated designs [9][10][11], shape memory designs [12], and soft robot designs [13][14][15]. Several hybrid driving schemes have also been applied, including pneumatic muscles with embedded elastic rods [16], and the system combining the concentric tube robot and the notched continuum robot [17]. ...
Concentric tube robots (CTRs) are a promising prospect for minimally invasive surgery due to their inherent compliance and ability to navigate in constrained environments. Existing mechanics-based kinematic models typically neglect friction, clearance, and torsion between each pair of contacting tubes, leading to large positioning errors in medical applications. In this paper, an improved kinematic modeling method is developed. The effect of clearance on tip position during concentric tube assembly is compensated by the database method. The new kinematic model is mechanic-based, and the impact of friction moment and torsion on tubes is considered. Integrating the infinitesimal torsion of the concentric tube robots eliminates the errors caused by the interaction force between the tubes. A prototype is built, and several experiments with kinematic models are designed. The results indicate that the error of tube rotations is less than 2 mm. The maximum error of the feeding experiment does not exceed 0.4 mm. The error of the new modeling method is lower than that of the previous kinematic model. This paper has substantial implications for the high-precision and real-time control of concentric tube robots.
... There are several ways to accomplish this. For example, the joint can either be operated using wires [25] and cables [26] or be directly driven by motors [27]. The mechanical challenge of applying motors directly to the rotation axis of the joint lies in the high torque required in some applications. ...
The universal joint is a senior machine element. With the purpose of exploring new applications this paper focuses on active universal joints with three degrees of freedom. This means to embed small motors acting on its gimbals. The objective of this study is therefore to investigate the viability of the proposition through an experiment and formulate a mathematical model that allows for exploring the limits of the design using numerical simulations. A specific joint was designed and manufactured that included, in addition to the driving motor, two further drives at the crosshead. In terms of the operation of the system, this study aimed to investigate its limitations and analyze its kinematics and dynamics, identifying the backlash and possible impact torque. A new approach was proposed for the control of the active universal joint by moving the manipulator’s end-effector from one point to another on an orthodromic trajectory. The orthodromic trajectory is related to a fixed Euler vector, which is presented in a conical motion context combined with a spin motion of the end-effector. Numerical results using the physical model were compared to the experimental results to determine the application limits of the joint.
... Most of the proposed designs are aimed at simplifying the structures of cable-operated continuum robots [82,81,83,46]. ...
Resolution of the inverse kinematic model of continuum robots using Meta-heuristic approaches
