Analysis of Optimal Cable Configurations in the Design of a 3-DOF Cable-Driven Robot Leg

2014 ◽  
Author(s):  
Joshua T. Bryson ◽  
Sunil K. Agrawal
Keyword(s):  
Range Of Motion ◽  
Degrees Of Freedom ◽  
Serial Robot ◽  
Placement And Routing ◽  
Robot Leg

The operational workspace of a cable-driven serial robot is largely dictated by the choice of cable placement and routing. As robot complexity increases with additional cables and degrees of freedom, the problem of designing a cable architecture can quickly become challenging. This paper builds upon a previously described methodology to identify and analyze optimal cable configurations, expanding the approach to a 3-DoF robot leg driven by four cables. The methodology is used to analyze configuration trends in the routing and placement of the cables which achieve the desired range of motion for the robot. The results of the analysis are used to inform the design of a cable architecture which is shown to be capable of controlling the robot through the desired task.

Methodology to Identify and Analyze Optimal Cable Configurations in the Design of Cable-Driven Serial Manipulators

2013 ◽  
Author(s):  
Joshua T. Bryson ◽  
Sunil K. Agrawal
Keyword(s):  
Range Of Motion ◽  
Mechanism Design ◽  
Critical Parameters ◽  
Robot Design ◽  
Serial Manipulators ◽  
General Terms ◽  
Placement And Routing ◽  
Robot Leg

The choice of cable placement and routing for a cable-driven serial manipulator has profound effects on the operational workspace of the mechanism. Poor choices in cable attachment can hamper or preclude the ability of the mechanism to perform a desired task, while a clever configuration might allow for an expanded workspace and kinematic redundancies, providing additional capability and flexibility. This paper outlines a methodology to identify and analyze optimal cable configurations for a serial manipulator which maximize operational workspace subject to mechanism design and configuration constraints. This process is first described in general terms for a generic 2-link robot and then applied to an illustrative example of a cable-driven robot leg. The methodology is used to determine the placement and routing of the cables to achieve the desired range of motion, as well as highlight the critical parameters within the cable configuration and identify possible areas of improvement in the overall robot design.

Configuration Robustness Analysis of the Optimal Design of Cable-Driven Manipulators

2016 ◽  
Vol 8 (6) ◽  
Author(s):  
Joshua T. Bryson ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Optimal Design ◽  
Stochastic Optimization ◽  
High Dimension ◽  
Degrees Of Freedom ◽  
Robustness Analysis ◽  
Optimal Solution ◽  
Design Parameters ◽  
Robot Leg ◽  
Robot Performance

Designing an effective cable architecture for a cable-driven robot becomes challenging as the number of cables and degrees of freedom of the robot increase. A methodology has been previously developed to identify the optimal design of a cable-driven robot for a given task using stochastic optimization. This approach is effective in providing an optimal solution for robots with high-dimension design spaces, but does not provide insights into the robustness of the optimal solution to errors in the configuration parameters that arise in the implementation of a design. In this work, a methodology is developed to analyze the robustness of the performance of an optimal design to changes in the configuration parameters. This robustness analysis can be used to inform the implementation of the optimal design into a robot while taking into account the precision and tolerances of the implementation. An optimized cable-driven robot leg is used as a motivating example to illustrate the application of the configuration robustness analysis. Following the methodology, the effect on robot performance due to design variations is analyzed, and a modified design is developed which minimizes the potential performance degradations due to implementation errors in the design parameters. A robot leg is constructed and is used to validate the robustness analysis by demonstrating the predicted effects of variations in the design parameters on the performance of the robot.

A Model of the Human Spine: Forward and Inverse Kinematics

1992 ◽  
Author(s):  
Sunil Kumar Agrawal ◽  
Siyan Li ◽  
Glen Desmier
Keyword(s):  
Range Of Motion ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Joint Angles ◽  
Human Spine ◽  
Forward And Inverse Kinematics ◽  
Position And Orientation ◽  
Three Degrees Of Freedom ◽  
Adjacent Vertebra

Abstract The human spine is a sophisticated mechanism consisting of 24 vertebrae which are arranged in a series-chain between the pelvis and the skull. By careful articulation of these vertebrae, a human being achieves fine motion of the skull. The spine can be modeled as a series-chain with 24 rigid links, the vertebrae, where each vertebra has three degrees-of-freedom relative to an adjacent vertebra. From the studies in the literature, the vertebral geometry and the range of motion between adjacent vertebrae are well-known. The objectives of this paper are to present a kinematic model of the spine using the available data in the literature and an algorithm to compute the inter vertebral joint angles given the position and orientation of the skull. This algorithm is based on the observation that the backbone can be described analytically by a space curve which is used to find the joint solutions..

Simulated Compensatory Motion of Transradial Prostheses

2008 ◽  
Author(s):  
Derek Lura ◽  
Rajiv Dubey ◽  
Stephanie L. Carey ◽  
M. Jason Highsmith
Keyword(s):  
Range Of Motion ◽  
Shoulder Joint ◽  
Degrees Of Freedom ◽  
Biomechanical Model ◽  
Elbow Flexion ◽  
Limited Range ◽  
Joint Movement ◽  
Range Of Movement ◽  
Limited Range Of Motion ◽  
Compensatory Motion

The prostheses used by the majority of persons with hand/arm amputations today have a very limited range of motion. Transradial (below the elbow) amputees lose the three degrees of freedom provided by the wrist and forearm. Some myoeletric prostheses currently allow for forearm pronation and supination (rotation about an axis parallel to the forearm) and the operation of a powered prosthetic hand. Older body-powered prostheses, incorporating hooks and other cable driven terminal devices, have even fewer degrees of freedom. In order to perform activities of daily living (ADL), a person with amputation(s) must use a greater than normal range of movement from other body joints to compensate for the loss of movement caused by the amputation. By studying the compensatory motion of prosthetic users we can understand the mechanics of how they adapt to the loss of range of motion in a given limb for select tasks. The purpose of this study is to create a biomechanical model that can predict the compensatory motion using given subject data. The simulation can then be used to select the best prosthesis for a given user, or to design prostheses that are more effective at selected tasks, once enough data has been analyzed. Joint locations necessary to accomplish the task with a given configuration are calculated by the simulation for a set of prostheses and tasks. The simulation contains a set of prosthetic configurations that are represented by parameters that consist of the degrees of freedom provided by the selected prosthesis. The simulation also contains a set of task information that includes joint constraints, and trajectories which the hand or prosthesis follows to perform the task. The simulation allows for movement in the wrist and forearm, which is dependent on the prosthetic configuration, elbow flexion, three degrees of rotation at the shoulder joint, movement of the shoulder joint about the sternoclavicular joint, and translation and rotation of the torso. All joints have definable restrictions determined by the prosthesis, and task.

COMPARATIVE KINEMATIC ANALYSIS OF THE RANGE OF MOVEMENT OF A NORMAL HUMAN KNEE JOINT, STANDARD ARTIFICIAL KNEE AND NOVEL ARTIFICIAL HIGH FLEXION KNEE

2010 ◽  
Vol 22 (01) ◽  
pp. 41-45
Author(s):  
Sam Prasanna Rajkumar ◽  
Sudesh Sivarasu ◽  
Lazar Mathew
Keyword(s):  
Knee Joint ◽  
Range Of Motion ◽  
Degrees Of Freedom ◽  
Range Of Movement ◽  
High Flexion ◽  
Additional Degree ◽  
Normal Knee ◽  
Standard Version ◽  
Knee Movement ◽  
Human Knee Joint

Total Knee Arthroplasty (TKA) using standard artificial knee implant has a limitation in restriction in the range of motion and freedom of movements'. This study was worked out to compare the kinematics of a reconstructed 3D knee with standard and high flexion artificial knee designs. A CT bone model reconstructed with MIMICS for a 3D normal knee joint and the simulation was done for normal knee, standard version of artificial knee as well as the high flexion knee designs. The results of the analyses, provides us an insight that high flexion designs were most suited and gives increased range of motion and also provides an additional degree of freedom so that it almost mimics the normal knee movement. The high flexion design when tested under simulated environment provided a better functionality and increased movements. It was concluded that the normal knee has 6 degrees of freedom (DOF); the standard version has 1 rotation and 1 translation. The high flexion design provides 2 rotations and 1 translation.

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.

Posture Prediction Versus Inverse Kinematics

2001 ◽  
Author(s):  
Karim Abdel-Malek ◽  
Wei Yu ◽  
Zan Mi ◽  
E. Tanbour ◽  
M. Jaber
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Human Performance ◽  
Inverse Kinematic ◽  
Cost Functions ◽  
Optimization Approach ◽  
Final Position ◽  
Serial Robot ◽  
Posture Prediction

Abstract Inverse kinematics is concerned with the determination of joint variables of a manipulator given its final position or final position and orientation. Posture prediction also refers to the same problem but is typically associated with models of the human limbs, in particular for postures assumed by the torso and upper extremities. There has been numerous works pertaining to the determination and enumeration of inverse kinematic solutions for serial robot manipulators. Part of these works have also been directly extended to the determination of postures for humans, but have rarely addressed the choice of solutions undertaken by humans, but have focused on purely kinematic solutions. In this paper, we present a theoretical framework that is based on cost functions as human performance measures, subsequently predicting postures based on optimizing one or more of such cost functions. This paper seeks to answer two questions: (1) Is a given point reachable (2) If the point is reachable, we shall predict a realistic posture. We believe that the human brain assumes different postures driven by the task to be executed and not only on geometry. Furthermore, because of our optimization approach to the inverse kinematics problem, models with large number of degrees of freedom are addressed. The method is illustrated using several examples.

Singularity Analysis of Serial Robot-Manipulators

1996 ◽  
Vol 118 (4) ◽  
pp. 520-525 ◽  
Author(s):  
A. Karger
Keyword(s):  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Singularity Analysis ◽  
Singular Set ◽  
Singular Configurations ◽  
Special Cases ◽  
Serial Robot ◽  
Singular Configuration ◽  
Actual Configuration

This paper is devoted to the description of the set of all singular configurations of serial robot-manipulators. For 6 degrees of freedom serial robot-manipulators we have developed a theory which allows to describe higher order singularities. By using Lie algebra properties of the screw space we give an algorithm, which determines the degree of a singularity from the knowledge of the actual configuration of axes of the robot-manipulator only. The local shape of the singular set in a neighbourhood of a singular configuration can be determined as well. We also solve the problem of escapement from a singular configuration. For serial robot-manipulators with the number of degrees of freedom different from six we show that up to certain exceptions singular configurations can be avoided by a small change of the motion of the end-effector. We also give an algorithm which allows to determine equations of the singular set for any serial robot-manipulator. We discuss some special cases and give examples of singular sets including PUMA 560.

Impedance Control of Two d.o.f. CPM Device for Elbow Joint

2014 ◽  
Vol 26 (4) ◽  
pp. 518-518
Author(s):  
Nobutomo Matsunaga ◽  
◽  
Shota Miyaguchi ◽  
Hiroshi Okajima ◽  
Shigeyasu Kawaji
Keyword(s):  
Range Of Motion ◽  
Musculoskeletal System ◽  
Elbow Joint ◽  
Degrees Of Freedom ◽  
Impedance Control ◽  
Reaction Force ◽  
Continuous Passive Motion ◽  
Collateral Ligament ◽  
Passive Motion ◽  
Post Surgery

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260004/16.jpg"" width=""200"" /> Two d.o.f. CPM device</span></div> Continuous passive motion (CPM) involves orthopedic or post-surgery physiotherapy. Following surgery to correct ulna collateral ligament (UCL) injury in the elbow, for example, excessively extending the UCL aggravates the injury and reaction force of the arm increases excessively near the end of the range of motion (ROM). Controlling pro/supination, i.e., rotarymotion of the wrist, effectively suppresses reaction force, but may extend the UCL excessively. We propose a 2 d.o.f. (degrees of freedom) impedance controller as a CPM device for the elbow to suppress reaction force based on the musculoskeletal system. </span>

scholarly journals Design of a Spherically Actuated Human Interaction Robot Head

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Nevan C. Hanumara ◽  
Alexander H. Slocum ◽  
Takeshi Mitamura
Keyword(s):  
Range Of Motion ◽  
Degrees Of Freedom ◽  
Limited Range ◽  
Human Interaction ◽  
The Other ◽  
Specific Information ◽  
Prior Art ◽  
Limited Range Of Motion ◽  
Robot Head

This paper presents the development of a mechanism for actuating a sphere holonomically about 3 degrees of freedom (DOF). The target application is a robot head for mounting inside a vehicle to provide a driver with companionship, location specific information, and other assistance, via head motions in conjunction with auditory communication. Prior art is reviewed and two designs are presented: One mechanism is located below the sphere and provides an unlimited range of motion (ROM), and the other is contained entirely within the sphere but has a limited range of motion. The latter is stable and easily mounted, provides a clean appearance, and is particularly suited to human interaction applications.

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