Comprehensive analyses of the elasto-plastic oblique contact-impact with vibration response

Robotics Computer Surgery

et al. 2020

Self Cite

Background Robot‐assisted puncture has gradually attracted more attention and practical clinical application. The lesion positioning and the needle positioning are the basis to ensure the accuracy of puncture and the key techniques in insertion operation. Methods A lesion positioning method is established which is realized only by the robot‐CT system without using external positioning system, and an omnidirectional needle positioning method is also developed and realized by using VRCM, in order to make the puncture needle always keep pointing to the lesion point. A CT‐guided surgical robotic system used for minimally invasive percutaneous lung is designed and the physical prototype is manufactured, to perform in‐vitro experiments, thereby to validate the effectiveness of the lesion positioning method and the feasibility of omnidirectional needle positioning method. Results The accuracy of established lesion positioning method based on three non‐collinear markers is within 3 mm, which is similar to that of the least squares method based on the five non‐coplanar markers, but the positioning efficiency can be improved by about 40%, and the non‐collinearity of markers is easier to be satisfied than non‐coplanarity in practical applications. The average calculation error of the established positioning method is 0.997 mm. Moreover, the omnidirectional positioning of the puncture needle under the designed surgical robot is feasible. Conclusions The designed surgical robot has good control accuracy and it can satisfy the requirements for use. The established lesion positioning method can provide a good precision basis for robot‐assisted puncture surgery. The suitable insertion point and insertion posture can be determined by the developed omnidirectional needle positioning method. This study can provide theoretical reference for further study of path planning or autonomous positioning.

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needs at least three markers.…”

Section: Mathematical Methodsmentioning

confidence: 99%

Lesion positioning method of a CT‐guided surgical robotic system for minimally invasive percutaneous lung

Zhang

Robotics Computer Surgery

et al. 2020

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“…A MATLAB program has been developed to analyze the captured video images. 39,40 After some sample tests, we select the frame rate of 30/s to capture the needle motion. Each pixel in each frame is assigned its corresponding gray-scale value ranging from 0 to 255, with the value 0 representing pure black and 255 representing pure white.…”

Section: Methodsmentioning

confidence: 99%

Experimental study of the optimum puncture pattern of robot-assisted needle insertion into hyperelastic materials

Zhao

et al. 2020

Proc Inst Mech Eng H

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The robot-assisted insertion surgery plays a crucial role in biopsy and therapy. This study focuses on determining the optimum puncture pattern for robot-assisted insertion, aiming at the matching problem of needle insertion parameters, thereby to reduce the pain for patients and to improve the reachability to the lesion point. First, a 6-degrees of freedom (DOFs) Computed Tomography (CT)-guided surgical robotic system for minimally invasive percutaneous lung is developed and used to perform puncture experiments. The effects of four main insertion factors on the robotic puncture are verified by designing the orthogonal test, where the inserting object is the artificial skin-like specimen with high transparent property and a digital image processing method is used to analyze the needle tip deflection. Next, the various phases of puncture process are divided and analyzed in detail in view of the tissue deformation and puncture force. Then, short discussion on the comparison of puncture force with different effect factors for the same beveled needle is presented. The same pattern can be observed for all of the cases. Finally, based on the experimental data, the formulations of the puncture force and needle deflection which depends on Gauge size, insertion velocity, insertion angle, and insertion depth are developed using the multiple regression method, which can be used to get an optimum puncture pattern under the constrains of minimum peak force and minimum needle tip deflection. The developed models have the effectiveness and applicability on determining the optimum puncture pattern for one puncture event, and which can also provide insights useful for the setting of insertion parameters in clinical practice.

“…Published amounts of research indicated that the effect of longitudinal and/or transverse vibration response during the motion and dynamic modeling can not be neglected for the elasto-plastic contact-impact events (Bazrafshan et al, 2014;Shafei et al, 2018). Authors previous works had done a quantitative analysis for mechanical vibration of the impacting object during impact events, and the longitudinal and transverse vibration responses were found to effect the normal and tangential velocities of the contact point after the impact, respectively.…”

Section: Dynamic Model With Vibration Responsementioning

confidence: 99%

“…Contact-impact is a particularly salient phenomenon which plays an important role pervasive in many applications involving the design and analysis of mechanical system, such as robotics (Banerjee et al, 2017;Flores-Abad et al, 2014), iron and steel metallurgy (Y. , vehicles (Yuan et al, 2016), civil structures (H. , composite structures (Mao et al, 2017;Park, 2017), and many other fields (Brake, 2015), since it affects motion parameters of the impacting object (e.g. rebound linear and an-gular velocity), contact force, and indentation deformation involving its patterns etc (Dong et al, 2018;Ghaednia et al, 2017b).…”

Section: Introductionmentioning

confidence: 99%

Analytical Study of Babbitt/steel Composite Structural Bars in Oblique Contact-impact with a Solid Flat Surface

2019

Mech. Sci.

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Abstract. The oblique contact-impact characteristic of the composite structural bar composed of Babbitt alloy and low-carbon steel (ZChSbSb11-6 ∕ AISI 1020) with a solid flat surface (AISI 1045) was studied theoretically and experimentally. The dynamic equation of the composite structural bar with vibration response during the contact-impact was established using the momentum theorem and assumed mode method, and the instantaneous contact forces during different impact phases were analyzed based on modified Jackson–Green model. Four sets of experiments (i.e. different proportion of Babbitt, ξ={1/8,1/2,3/4,7/8}) for the initial angle, θ=45∘, and different initial velocities were performed; and, the rebound linear and angular velocity of the contact point of composite structural bar after impact was calculated and compared with experimental results. Besides, the coefficient of restitution, the relation of contact force and contact deflection, and the permanent deformation were also compared for the composite structural bars with different proportions in combination, ξ. Three critical angles are found to determine whether the composite bar slides or not, but are prominently different for the composite bars with different ξ. In comparing with the experimental results, the numerical solutions of rebound linear and angular velocity had yield encourage results and, all relative errors were small, indicating that the simulations are in good agreement with the experimental results. Also, the oblique contact-impact behavior involving the coefficient of restitution, the relation of contact force and contact deflection, and the permanent deformation was explained in detail. It can be concluded that as the proportion of Babbitt ξ increases, the composite structural bar presents a characteristic of ease of deflection. And the contact-impact behavior of structural entity is closely related to the inherent properties of the elasto-plastic material, especially for the weak material of composite structures. The more easily the impacting object is deformed, the small the contact force during the contact-impact, which also indicates the yield strength of weak material is a very significant parameter in the event of collision. Such work could give conducive insights to contact-impact problems of the key parts or structures composed of composite materials in mechanical system.