scholarly journals Development of a Spherical Positioning Robot and Neuro-Navigation System for Precise and Repetitive Non-Invasive Brain Stimulation

2019 ◽  
Vol 9 (21) ◽  
pp. 4561
Author(s):  
Shin ◽  
Ryu ◽  
Cho ◽  
Yang ◽  
Lee
Keyword(s):  
Brain Stimulation ◽  
Navigation System ◽  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Human Head ◽  
Non Invasive ◽  
Serial Robot ◽  
The Subject ◽  
6 Degrees Of Freedom ◽  
Spherical Mechanism

Although non-invasive brain stimulation techniques do not involve surgical procedures, the challenge remains in correctly locating the stimulator from outside the head. There is a limit to which one can manually and precisely position and orient the stimulator or repeatedly move the stimulator around the same position. Therefore, in this study, we developed a serial robot with 6 degrees-of-freedom to move the stimulator and a neuro-navigation system to determine the stimulus point from looking at the shape of the subject’s brain. The proposed robot applied a spherical mechanism while considering the safety of the subject, and the workspace of the robot was designed considering the shape of the human head. Position-based visual servoing was applied to compensate for unexpected movements during subject stimulation. We also developed a neuro-navigation system that allows us visually to check the focus of the stimulator and the human brain at the same time and command the robot to the desired point. To verify the system performance, we first performed repeatability and motion compensation experiments of the robot and then evaluated the repeated biosignal response experiments through transcranial magnetic stimulation, a representative technique of non-invasive brain stimulation.

Feasibility Study of Force Measurement for Multi-digit Unconstrained Grasping via Fingernail Imaging and Visual Servoing

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Navid Fallahinia ◽  
Stephen A. Mascaro
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Field Of View ◽  
Imaging Method ◽  
Shear Forces ◽  
Maximum Value ◽  
6 Degrees Of Freedom ◽  
Finger Pad ◽  
Rms Errors

Abstract A fingernail imaging has been shown to be effective in estimating the finger pad forces along all three directions simultaneously in previous works. However, this method has never been used for the purpose of force measurement during a grasping task with multiple fingers. The objective of this paper is to demonstrate the grasp force-sensing capabilities of the fingernail imaging method integrated with a visual servoing robotic system. In this study, the fingernail imaging method has been used in both constrained and unconstrained multi-digit grasping studies. Visual servoing has been employed to solve the issue of keeping fingernail images in the field of view of the camera during grasping motions. Two grasping experiments have been designed and conducted to show the performance and accuracy of the fingernail imaging method to be used in grasping studies. The maximum value of root-mean-square (RMS) errors for estimated normal and shear forces during constrained grasping has been found to be 0.58 N (5.7%) and 0.49 N (9.2%), respectively. Moreover, a visual servoing system implemented on a 6-degrees-of-freedom (DOF) robot has been devised to ensure that all of the fingers remain in the camera frame at all times. Comparing unconstrained and constrained forces has shown that force collaboration among fingers could change based on the grasping condition.

Estimation of ACL Forces Utilizing a Novel Non-Invasive Methodology That Reproduces Knee Kinematics Between Sets of Knees

2003 ◽  
Author(s):  
Shon P. Darcy ◽  
Robert H. P. Kilger ◽  
Savio L.-Y. Woo ◽  
Richard E. Debski
Keyword(s):  
Degrees Of Freedom ◽  
Cruciate Ligament ◽  
Knee Kinematics ◽  
Acl Injuries ◽  
Non Invasive ◽  
Rehabilitation Protocols ◽  
Anterior Cruciate ◽  
6 Degrees Of Freedom ◽  
Rehabilitation Exercises

A non-invasive, non-contact methodology to estimate forces in the anterior cruciate ligament (ACL) in response to in vivo knee kinematics will allow surgical procedures and rehabilitation protocols for ACL injuries to be improved. During the last decade, intensive efforts have been made to quantify the forces in the ACL in vivo (Holden, 1994; Lundberg, 1997; Zacharias, 2001). With the use of these methods, valuable information on the forces experienced by the ACL has been obtained, however many of these methods were invasive, and involved direct contact with the ACL, which may affect the force measurements. It has been proposed at our research center that the forces in the ACL during activities of daily living and rehabilitation exercises can be estimated in a non-contact, non-invasive manner by reproducing in vivo kinematics in 6-degrees of freedom (DOF) on a cadaveric knee. Therefore, the specific aim of this study was to evaluate the feasibility of a non-invasive, non-contact methodology for estimating force in the ACL by reproducing average kinematics in 6-DOF degrees of freedom from one set of porcine knees (source) onto a separate set of porcine knees (target).

Design and Implementation of a Binary Redundant Manipulator With Cascaded Modules1

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Emmanouil Tzorakoleftherakis ◽  
Anastasia Mavrommati ◽  
Anthony Tzes
Keyword(s):  
Computational Complexity ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Redundant Manipulator ◽  
Stable States ◽  
Design And Implementation ◽  
Serial Robot ◽  
The Subject ◽  
Forward And Inverse Kinematics ◽  
Three Degrees Of Freedom

The subject of this paper is the design and implementation of a prototype snakelike redundant manipulator. The manipulator consists of cascaded modules eventually forming a macroscopically serial robot and is powered by shape memory alloy (SMA) wires. The SMAs (NiTi) act as binary actuators with two stable states and as a result, the repeatability of the manipulator's movement is ensured, alleviating the need for complex feedback sensing. Each module is composed of a customized spring and three SMA wires which form a tripod with three degrees of freedom (DOFs). Embedded microcontrollers networked with the I2C protocol activate the actuators of each module individually. In addition, we discuss certain design aspects and propose a solution that deals with the limited absolute stroke achieved by SMA wires. The forward and inverse kinematics of the binary manipulator are also presented and the tradeoff between maneuverability and computational complexity is specifically addressed. Finally, the functionality and maneuverability of this design are verified in simulation and experimentally.

Classification of Serial Robot-Manipulators with Nonremovable Singularities

1996 ◽  
Vol 118 (2) ◽  
pp. 202-208 ◽  
Author(s):  
A. Karger
Keyword(s):  
Degrees Of Freedom ◽  
Robot Manipulators ◽  
Removable Singularity ◽  
Singular Set ◽  
Singular Configurations ◽  
Serial Robot ◽  
Small Change ◽  
6 Degrees Of Freedom ◽  
4 Degrees Of Freedom

In this paper we discuss singular configurations of serial robot-manipulators with respect to their removability. A removable singularity is a singularity which can be removed from a motion of the end-effector by a small change of the motion. The most interesting situation appears for robot-manipulators with 5 degrees of freedom, because the case of 4 degrees of freedom is easy and singular configurations of robot-manipulators with 6 degrees of freedom are nonremovable. In the paper we give the complete list of all 5R robot-manipulators which have nonremovable singularities. The image of the singular set in the parameter space for such manipulators can be a plane, a quadric, a cylinder or an algebraic surface of degree 3 or 7. All of them are explicitly given.

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