Dynamic virtual fixture on the Euclidean group for admittance-type manipulator in deforming environments

Zhang, Dongwen; Zhu, Qingsong; Xiong, Jing; Wang, Lei

doi:10.1186/1475-925x-13-51

Cited by 9 publications

(4 citation statements)

References 29 publications

(25 reference statements)

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“…This configuration is redundant, and existing methods cannot simultaneously solve its IK timely and accurately. Point virtualization is useful in solving IK of robotic models [ 36 , 37 ], and collision avoidance with surrounding organs [ 38 ]. This serves as the basis of the geometric method we proposed in this study.…”

Section: Proposed Geometric Methodsmentioning

confidence: 99%

Non-iterative geometric approach for inverse kinematics of redundant lead-module in a radiosurgical snake-like robot

et al. 2017

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BackgroundSnake-like robot is an emerging form of serial-link manipulator with the morphologic design of biological snakes. The redundant robot can be used to assist medical experts in accessing internal organs with minimal or no invasion. Several snake-like robotic designs have been proposed for minimal invasive surgery, however, the few that were developed are yet to be fully explored for clinical procedures. This is due to lack of capability for full-fledged spatial navigation. In rare cases where such snake-like designs are spatially flexible, there exists no inverse kinematics (IK) solution with both precise control and fast response.MethodsIn this study, we proposed a non-iterative geometric method for solving IK of lead-module of a snake-like robot designed for therapy or ablation of abdominal tumors. The proposed method is aimed at providing accurate and fast IK solution for given target points in the robot’s workspace. n-1 virtual points (VPs) were geometrically computed and set as coordinates of intermediary joints in an n-link module. Suitable joint angles that can place the end-effector at given target points were then computed by vectorizing coordinates of the VPs, in addition to coordinates of the base point, target point, and tip of the first link in its default pose. The proposed method is applied to solve IK of two-link and redundant four-link modules.ResultsBoth two-link and four-link modules were simulated with Robotics Toolbox in Matlab 8.3 (R2014a). Implementation result shows that the proposed method can solve IK of the spatially flexible robot with minimal error values. Furthermore, analyses of results from both modules show that the geometric method can reach 99.21 and 88.61% of points in their workspaces, respectively, with an error threshold of 1 mm. The proposed method is non-iterative and has a maximum execution time of 0.009 s.ConclusionsThis paper focuses on solving IK problem of a spatially flexible robot which is part of a developmental project for abdominal surgery through minimal invasion or natural orifices. The study showed that the proposed geometric method can resolve IK of the snake-like robot with negligible error offset. Evaluation against well-known methods shows that the proposed method can reach several points in the robot’s workspace with high accuracy and shorter computational time, simultaneously.

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Section: Proposed Geometric Methodsmentioning

confidence: 99%

Non-iterative geometric approach for inverse kinematics of redundant lead-module in a radiosurgical snake-like robot

et al. 2017

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“…Nevertheless, our work is similar to ref. [31], in the choice of orientation representation and distance definition in SE(3).…”

Section: Virtual Guide Literaturementioning

confidence: 99%

“…The spatial compliance/stiffness matrix synthesis for admittance and impedance-controlled devices was also studied. In more recent work, 31 the authors studied the application of virtual guides in the deforming environment and proposed a novel framework of DVG for admittance-type devices. This framework in the Euclidean group SE(3) was proposed to enhance the surgical operation accuracy of admittance-type medical robotics in the deforming environment.…”

Section: Virtual Guide Literaturementioning

confidence: 99%

Toward an Intuitive and Iterative 6D Virtual Guide Programming Framework for Assisted Human–Robot Comanipulation

Restrepo¹,

Raiola²,

Guerry³

et al. 2020

Robotica

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SUMMARY In human–robot comanipulation, virtual guides are an important tool used to assist the human worker as they constrain the movement of the robot to improve the task accuracy and to avoid undesirable effects, such as collisions with the environment. Consequently, the physical effort and cognitive overload are reduced during accomplishment of comanipulative tasks. However, the construction of virtual guides often requires expert knowledge and modeling of the task, which restricts the usefulness of virtual guides to scenarios with fixed constraints. Moreover, few approaches have addressed the implementation of virtual guides enforcing orientation constraints and, when done, these approaches have treated translation and orientation separately, and consequently there is no synchronization of the translational and rotational motions. To overcome these challenges and enhance the programming flexibility of virtual guides, we present a new framework that allows the user to create 6D virtual guides through XSplines which we define as a combination of Akima splines for the translation component and spherical cubic interpolation of quaternions for the orientation component. For complex tasks, the user is able to initially define a 3D virtual guide and then use this assistance in translational motion to concentrate only on defining the orientations along the path. It is also possible for the user to modify a particular point or portion of a guide while being assisted by it. We demonstrate in an industrial scenario that these innovations provide an intuitive solution to extend the use of virtual guides to 6 degrees of freedom and increase the human worker’s comfort during the programming phase of these guides in an assisted human–robot comanipulation context.

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“…Generation of AC geometry has been the focus of numerous works in the literature because tissue deformability and the lack of structural features create major challenges in defining and updating the geometries. Examples include concave tunnels, dynamic admittance‐type, streaming Point Clouds‐based and 3D eye gaze‐based . Fewer studies have proposed enforcement methods, but as the generation of geometry and methods of tracking improve and practical implementations become more likely, the need for novel and efficient enforcement methods will grow.…”

Section: Introductionmentioning

confidence: 99%

Performance metrics for guidance active constraints in surgical robotics

Enayati

Ferrigno

Momi

2017

Robotics Computer Surgery

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Active constraint (AC)/virtual fixture (VF) is among the most popular approaches towards the shared execution of subtasks by the surgeon and robotic systems. As more possibilities appear for the implementation of ACs in surgical scenarios, the need to introduce methods that guarantee a safe and intuitive user-interaction increases. The presence of the human in the loop adds a layer of interactivity and adaptability that renders the assessment of such methods non-trivial. In most works, guidance ACs have been evaluated mainly in terms of enhancement of accuracy and completion time with little regard for other aspects such as human factors, even though the continuous engagement of these methods can considerably degrade the user experience. This paper proposes a set of performance metrics and considerations that can help evaluate guidance ACs with reference to accuracy enhancement, force characteristics and subjective aspects. The use of these metrics is demonstrated through two sets of experiments on 12 surgeons and 6 inexperienced users.

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Dynamic virtual fixture on the Euclidean group for admittance-type manipulator in deforming environments

Cited by 9 publications

References 29 publications

Non-iterative geometric approach for inverse kinematics of redundant lead-module in a radiosurgical snake-like robot

Non-iterative geometric approach for inverse kinematics of redundant lead-module in a radiosurgical snake-like robot

Toward an Intuitive and Iterative 6D Virtual Guide Programming Framework for Assisted Human–Robot Comanipulation

Performance metrics for guidance active constraints in surgical robotics

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