scholarly journals Partial gravity compensation of a surgical robot

2021 ◽  
Vol 18 (3) ◽  
pp. 172988142110154
Author(s):  
Omar W Maaroof ◽  
Saad Zaghlul Saeed ◽  
Mehmet İsmet Can Dede
Keyword(s):  
Optimization Method ◽  
Surgical Robot ◽  
Gravity Compensation ◽  
Surgical Robots ◽  
Novel Approach ◽  
Partial Gravity ◽  
Safety Features ◽  
Compact Design ◽  
Multiple Domains ◽  
Compensation Design

Surgical robots are safety-critical devices that require multiple domains of safety features. This article focuses on the passive gravity compensation design optimization of a surgical robot. The limits of this optimization are related with the safety features including minimization of the total moving mass/inertia and compactness of the design. The particle swarm optimization method is used as a novel approach for the optimization of a parallel remote-center-of-motion mechanism. A compact design is achieved by partially balancing the mechanism, which also decreases the torque requirements from the actuators.

scholarly journals 3D Mapping of the Sprinkler Activation Time

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1450
Author(s):  
Wojciech Węgrzyński ◽  
Grzegorz Krajewski ◽  
Piotr Tofiło ◽  
Wolfram Jahn ◽  
Aleksander Król ◽  
...  
Keyword(s):  
Fire Safety ◽  
Natural Ventilation ◽  
Sprinkler System ◽  
Activation Time ◽  
Ansys Fluent ◽  
Design Fire ◽  
Novel Approach ◽  
Rti Model ◽  
Safety Features

Sprinkler activation is one of the key events defining the course of a compartment fire. The time when activation occurs is commonly used in the determination of the design fire scenario, which is the cornerstone of the design of building fire safety features. A well-known model of sprinkler activation (response time index (RTI) model) was introduced into the numerical scheme of the ANSYS Fluent computational fluid dynamics (CFD) package. The novel way in which the model is used is the calculation of the time for sprinkler activation within each discrete cell of the domain. The proposed novel approach was used in a case-study to assess the effects of comfort mode natural ventilation on a sprinkler’s activation pattern. It was found that hinged vents in the comfort mode had a significant effect on sprinkler activation, both in terms of delaying it as well as limiting the total number of cells in which the sprinkler would have activated. In some scenarios with a hinged vent, no activation was observed in the central point of the vent, possibly indicating problems with the autonomous triggering of the fire mode of such a device. It was also found that the RTI and C (related to the conductive transport of sprinkler fitting) parameter values had a moderate influence on sprinkler activation time—only for high-temperature sprinklers (≥ 141 °C). This study shows the applicability of the 3D activation time mapping for research focused on the fire safety of sprinkler-protected compartments and for the performance-based approach to sprinkler system design. Even though the RTI model is the industry standard for the determination of sprinkler response, the model implementation in ANSYS Fluent was not validated. This means that sources of uncertainty, mainly connected with the determination of flow velocity and temperature are not known, and the model should be used with caution. An in-depth validation is planned for subsequent studies.

Automated Tool-Orientation Determinations for 4-Axis Non-Gouge, Non-Interference Milling of Axial-Flow Compressors Airfoils

2007 ◽  
Author(s):  
Zezhong C. Chen ◽  
Gang Liu
Keyword(s):  
Manufacturing Industry ◽  
Axial Flow ◽  
Optimization Method ◽  
Free Form ◽  
Software Systems ◽  
Cnc Milling ◽  
Novel Approach ◽  
Cad Cam ◽  
Free Form Surfaces ◽  
Axial Flow Compressors

As important components of gas turbine engines, axial-flow compressors have been improved with a more complex and accurate airfoil design to meet high aerodynamic requirements; specifically, the pressure and suction surfaces of the airfoils (or blades) are now represented with free-form surfaces in CAD software systems. Since quality of the blades affects efficiency of the engines and safety of the aircrafts, some types of compressors are produced with the blades and the hub as a single piece on 4-axis CNC milling machines. However, it is still quite challenging to automatically determine cutter sizes and orientations without gouging and interference during the 4-axis milling, because the geometric shape of the blades is complex and the blades overlap with each other. As a result, the established method of determining tool size and orientation in industry is by trial and error in a repetitive process of selecting cutters and planning tool-paths with CAM systems. To address this problem, a novel approach is proposed to automatically determine cutter sizes and orientations for 4-axis milling of the axial-flow compressors blades without gouging and interference. The main contribution of this work is that (1) a mathematical model for optimizing cutter sizes in 4-axis milling is established; and (2) by applying a global optimization method — the particle swarm optimization method — to this model, the maximum allowable size of a cutter and its corresponding orientation can be found at each cutter-contact (CC) point on the surface being machined. Therefore, all the maximum allowable sizes of cutters for all the CC points and the corresponding cutter orientations can be computed. A group of standard cutters are then selected; each of which can sweep particular CC points without damaging the compressor. Since it is efficient and reliable, this newly proposed approach can be directly implemented in commercial CAD/CAM software systems to benefit the manufacturing industry.

Static balancer for the neck of a face robot

2013 ◽  
Vol 228 (3) ◽  
pp. 561-568 ◽  
Author(s):  
Changhyun Cho ◽  
Seungjong Kim
Keyword(s):  
Degree Of Freedom ◽  
Experimental Results ◽  
The Other ◽  
Gravity Compensation ◽  
Gravity Compensator ◽  
Face Robot ◽  
The Face ◽  
Static Balancer ◽  
Compact Design

We propose a 3-degree of freedom gravity compensator for the neck of a robotic face. The neck of the face robot is configured with yaw-pitch-pitch-roll rotations. Since the yaw rotation is made parallel to gravity, only the pitch-pitch-roll rotations are considered for gravity compensation. The 1-degree of freedom gravity compensator is located at the first pitch joint. A 2-degree of freedom gravity compensator equivalent to the existing gravity compensator is proposed and applied to the second pitch and roll rotations. A parallelogram is adopted between the first and second pitch rotations. One end of the 2-degree of freedom gravity compensator is attached at the parallelogram and the other is fixed at the face. Wires are used to realize a zero-length spring for all gravity compensators and all springs are located at the base for compact design. Experimental results for gravity compensation show that gravitational torques were effectively counterbalanced by the proposed 3-degree of freedom gravity compensator.

Improved Surgical Robot Design Using a Novel Compliant Rolling-Contact Joint

2019 ◽  
Author(s):  
Carl A. Nelson ◽  
Cole A. Dempsey ◽  
Ethan R. Brush ◽  
M. Amine Laribi
Keyword(s):  
Human Robot Interaction ◽  
Rolling Contact ◽  
Surgical Robot ◽  
Excessive Force ◽  
Robot Interaction ◽  
Rolling Element ◽  
Spherical Wrist ◽  
Improved Design ◽  
Safety Features ◽  
And Control

Abstract This paper presents an improved design concept for a surgical robot that contributes to improved human-robot interaction and precise positioning of surgical tools. Based on a spherical wrist design, the robot incorporates new human-safe features limiting its ability to apply excessive force and uses a novel adaptation of the compliant rolling-element (CORE) joint suitable for conical rolling surfaces. The proposed safety features aim to provide novel functionality by mechanically disengaging the drive in overload conditions. This approach avoids the necessity of force sensing and control to detect and compensate for unintended device collisions. Further, proof of concept of a novel compliant rolling-element joint is presented as a low-backlash alternative to bevel gear pairs for heightened precision in angular positioning.

scholarly journals Novel Approach for Visualizing Multiple Domains of Quality of Life Scales

2019 ◽  
Vol 12 (5) ◽  
Author(s):  
Nobuhiro Ikemura ◽  
Takehiro Kimura ◽  
Mitsuaki Sawano ◽  
Keiichi Fukuda ◽  
Seiji Takatsuki ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Novel Approach ◽  
Multiple Domains

scholarly journals Solving the Time-Varying Inverse Kinematics Problem for the Da Vinci Surgical Robot

2019 ◽  
Vol 9 (3) ◽  
pp. 546 ◽  
Author(s):  
Long Bai ◽  
Jianxing Yang ◽  
Xiaohong Chen ◽  
Pei Jiang ◽  
Fuqiang Liu ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Da Vinci ◽  
Newton Iteration ◽  
Surgical Robot ◽  
Unitary Matrix ◽  
Surgical Robots ◽  
Unknown Variable ◽  
Inverse Kinematics Problem ◽  
Da Vinci Surgical Robot ◽  
Order Nonlinear Equation

A dialytic-elimination and Newton-iteration based quasi-analytic inverse kinematics approach is proposed for the 6 degree of freedom (DOF) active slave manipulator in the Da Vinci surgical robot and other similar systems. First, the transformation matrix-based inverse kinematics model is derived; then, its high-dimensional nonlinear equations are transformed to a high-order nonlinear equation with only one unknown variable by using the dialytic elimination with a unitary matrix. Finally, the quasi-analytic solution is eventually obtained by the Newton iteration method. Simulations are conducted, and the result show that the proposed quasi-analytic approach has advantages in terms of accuracy (error < 0.00004 degree (or mm)), solution speed (< 20 ms) and is barely affected by the singularity during intermediate calculations, which proves that the approach meets the real-time and high-accuracy requirements of master‒slave mapping control for the Da Vinci surgical robots and other similar systems. In addition, the proposed approach can also serve as a design reference for other types of robotic arms that do not satisfy the Pieper principle.

Fuzzy PID Sliding Mode Control for Robotics: An Application to Surgical Robot

2019 ◽  
Vol 12 (2) ◽  
pp. 118-129
Author(s):  
Mohd S. Qureshi ◽  
Pankaj Swarnkar ◽  
Sushma Gupta
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Technological Development ◽  
Minimal Invasive ◽  
Surgical Robot ◽  
System Stability ◽  
Surgical Robots ◽  
Mode Control ◽  
Control Methodology

Background: Continually in view of the fact that digital technology entered in the Operating Theatre (OT), surgery has moved out through one of the big revolutions in medical field. Robotic-Assisted Surgery (RAS) is a way of technological development in the medical environment, designed to thrash the limitations of Minimal Invasive Surgery (MIS). Surgical robots carry out operation with the motion control of manipulator joints on the patient. Precise and fine control of these robots is very imperative. Methods: The paper depicts the control methodology for surgical robots based on the combination of Sliding Mode Control (SMC) with Fuzzy Logic Control (FLC). The destructive chattering phenomenon in SMC is circumvented by espousing FLC in SMC. System stability is investigated using Lyapunov theorem. All numerical simulations have been carried out using MATLAB tool for 2 DOF robot manipulator formulated for trajectory tracking process which shows the efficacy of the proposed methodology. Results: The simulation results of FSMC are compared with the conventional SMC which represents the improvement of control law for the attainment of optimized results. Conclusion: The proposed methodology in the paper is very much suitable in controlling surgical robot during typical surgical operations. The effectiveness of proposed control methodology is shown using simulation studies in the paper.

Efficient Post-Tensioned Slab Design Informed Through Topology Optimization

2019 ◽  
Author(s):  
Mark Sarkisian ◽  
Eric Long ◽  
Alessandro Beghini ◽  
Rupa Garai ◽  
David Shook ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Design Method ◽  
Design Procedure ◽  
Optimization Method ◽  
High Rise ◽  
Load Paths ◽  
Novel Approach ◽  
Optimal Load ◽  
Construction Documents ◽  
Post Tensioned

<p>Post-tensioned (PT) flat-plate gravity framing systems are highly efficient and reduce embodied carbon, improve construction speed, and reduce seismic mass when compared to conventional reinforced concrete framing systems. While efficiency is especially apparent in multi-span applications with regular orthogonal support arrangement, single-span or irregular support applications are common in high-rise buildings.</p><p>A novel approach to determining PT tendon arrangements has been applied to several buildings informed by topology optimization results. Topology optimization is an optimization method which determines optimal load paths in a finite element continuum. By orienting PT tendons along the optimal load paths suggested by topology optimization, several applications have consistently demonstrated reductions in post-tensioned tendon quantities while the amount of mild reinforcement is maintained unchanged. Many of the observed tendon layouts do not follow traditional uniform/banded layouts. Also, the deflection performance is enhanced since tendons are placed in a manner consistent with the load demands.</p><p>This new design method has been applied to three buildings and coordinated with construction teams. This presentation will discuss the design procedure which was developed through construction documents as applied to three buildings.</p>

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