Design of a Humanoid Shoulder Complex Emulating Human Shoulder Girdle Motion Using the Minimum Number of Actuators

2016 ◽  
Vol 13 (04) ◽  
pp. 1550045
Author(s):  
Jeremy T. Newkirk ◽  
Michael M. Stanišić
Keyword(s):  
Range Of Motion ◽  
Entire Range ◽  
Degrees Of Freedom ◽  
Shoulder Girdle ◽  
End Effector ◽  
Natural Motion ◽  
Minimum Number ◽  
Shoulder Complex ◽  
Parallel Platform ◽  
Motion Studies

This paper describes a design for a humanoid shoulder complex that replicates human shoulder girdle motion. The goal here is to use the minimum number of actuators to keep the mechanism as light as possible to help ensure that a humanoid is not too top heavy. The human shoulder girdle has two degrees-of-freedom (DOF), which means the minimum number of actuators is also two. The proposed mechanism is a novel parallel platform with two DOF that acts as a pointing mechanism. As the mechanism is articulated the end-effector moves, which results in contraction or elongation, mimicking the natural motion of the human shoulder girdle. A parallel platform was chosen because of the inherent rigidity and a large workspace is not necessary. The mechanism presented here was chosen because of its simplicity and ability to track human shoulder girdle motion. Motion studies were conducted to collect data representing human shoulder girdle motion, which was used to optimize the mechanism for tracking human shoulder girdle motion as closely as possible. A second optimization was performed to ensure that the mechanism avoids singularities throughout its entire range of motion. The results show that this design closely replicates human shoulder girdle motion and is well-suited for use as a humanoid shoulder girdle to increase the range of motion for a humanoid arm.

scholarly journals Spinal and Shoulder Girdle Range of Motion in Elite Female Volleyball Athletes

2015 ◽  
Vol 22 (3) ◽  
pp. 143-147
Author(s):  
Arletta Hawrylak ◽  
Dorota Wojna ◽  
Krystyna Chromik
Keyword(s):  
Range Of Motion ◽  
Body Mass ◽  
Body Height ◽  
Shoulder Girdle ◽  
Average Height ◽  
Spine Mobility ◽  
Shoulder Complex ◽  
Average Body Mass ◽  
Average Body ◽  
Group 1

Abstract Introduction. Doing asymmetric sports when one suffers from body asymmetry may cause body posture disorders. The aim of the study was to assess the spinal and shoulder complex mobility of professionally trained volleyball athletes compared to that of their peers who do not practise any sports. Material and methods. The study involved 60 participants divided into two groups. Group 1 consisted of 30 girls aged 14 years. The average height in the group was 176.37 ± 6.29 cm, and the average body mass was 64.53 ± 7.12 kg. Group 2 consisted of 30 girls aged 15.6 ± 1.12 years who did not practise any sports. The average body height in this group was 159.37 ± 3.33 cm, and the average body mass was 51.83 ± 4.03 kg. The dominant limb was defined on the basis of lateralization. The spinal range of motion was measured by means of a Saunders digital inclinometer, and the shoulder complex range of motion was examined using the goniometric method. Means and standard deviations were calculated, and Student’s t-test was applied in order to determine the differences between the two groups. Results. The differences in the values obtained in the two groups for the spinal range of motion in the sagittal plane were statistically significant only for the range of lumbar spine bending and extension. It was found that group 1 had a higher range of spine mobility in the frontal and transverse planes, and the differences were statistically significant in all the assessed ranges towards the dominant limb. An analysis of the shoulder girdle range of motion in the groups revealed that the differences were also statistically significant in all of the examined ranges. Conclusion. Professional volleyball practice can cause an increase in spine flexibility in most of its ranges, and the shoulder girdle range of motion in female volleyball players can exceed population norms, especially for the upper dominant limb.

scholarly journals Redundancy Resolution Using Tractrix: Simulations and Experiments

2009 ◽  
Author(s):  
V. C. Ravi ◽  
Subrata Rakshit ◽  
Ashitava Ghosal
Keyword(s):  
Degrees Of Freedom ◽  
Redundancy Resolution ◽  
Redundant Manipulator ◽  
End Effector ◽  
Redundant Robots ◽  
Natural Motion ◽  
Fixed Base ◽  
Effective Use ◽  
Actuated Joints ◽  
Present Simulation

Hyper-redundant robots are characterized by the presence of a large number of actuated joints, many more than the number required to perform a given task. These robots have been proposed and used for many application involving avoiding obstacles or, in general, to provide enhanced dexterity in performing tasks. Making effective use of the extra degrees of freedom or resolution of redundancy have been an extensive topic of research and several methods have been proposed in literature. In this paper, we compare three known methods and show that an algorithm based on a classical curve called the tractrix leads to a more ‘natural’ motion of the hyper-redundant robot with the displacements diminishing from the end-effector to the fixed base. In addition, since the actuators at the base ‘see’ the inertia of all links, smaller motion of the actuators nearer to the base results in a smoother motion of the end-effector as compared to other two approaches. We present simulation and experimental results performed on a prototype eight link planar hyper-redundant manipulator.

scholarly journals Refined clothespin relocation test and assessment of motion

2016 ◽  
Vol 41 (3) ◽  
pp. 294-302 ◽  
Author(s):  
Ali Hussaini ◽  
Peter Kyberd
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Assessment Tools ◽  
Single Degree Of Freedom ◽  
End Effector ◽  
Upper Limb Prosthesis ◽  
Compensatory Motion ◽  
User Groups ◽  
Motion Studies ◽  
Limb Prosthesis

Background:Advancements in upper limb prosthesis design have focused on providing increased degrees of freedom for the end effector through multiple articulations of a prosthetic hand, wrist and elbow. Measuring improvement in patient function with these devices requires development of appropriate assessment tools.Objectives:This study presents a refined clothespin relocation test for measuring performance and assessing compensatory motion between able-bodied subjects and subjects with upper limb impairments.Study design:Comparative analysis.Methods:Trunk and head motions of 13 able-bodied subjects who performed the refined clothespin relocation test were compared to the motion of a transradial prosthesis user with a single degree of freedom hand.Results:There were observable differences between the prosthesis user and the able-bodied group. The assessment used provided a clear indication of the differences in motion through analysis of compensatory motion.Conclusion:The refined clothespin relocation test provides additional benefits over the standard clothespin assessment and makes identification of compensatory motions easily identifiable to the researcher. While this article establishes the method for the new assessment, further validation will need to be performed with more users.Clinical relevanceThe refined test provides a more defined structure for the trajectory of the hand/terminal device than the standard protocol for the clothespin relocation test. This will help researchers interested in motion studies of limb segments to efficiently compare and analyse motion between able-bodied and prosthesis user groups.

Control Algorithms for 3-DoF Handheld Robotic Devices Used in Orthopedic Surgery

2019 ◽  
Vol 04 (02) ◽  
pp. 1950002
Author(s):  
Martin Klemm ◽  
Uwe D. Hanebeck ◽  
Harald Hoppe
Keyword(s):  
Range Of Motion ◽  
Orthopedic Surgery ◽  
Degrees Of Freedom ◽  
Limited Range ◽  
Robotic Systems ◽  
Control Algorithms ◽  
End Effector ◽  
Multiple Degrees Of Freedom ◽  
Limited Range Of Motion ◽  
Robotic Devices

Nowadays, robotic systems are an integral part of many orthopedic interventions. Stationary robots improve the accuracy but also require adapted surgical workflows. Handheld robotic devices (HHRDs), however, are easily integrated into existing workflows and represent a more economical solution. Their limited range of motion is compensated by the dexterity of the surgeon. This work presents control algorithms for HHRDs with multiple degrees of freedom (DOF). These algorithms protect pre- or intraoperatively defined regions from being penetrated by the end effector (e.g., a burr) by controlling the joints as well as the device’s power. Accuracy tests on a stationary prototype with three DOF show that the presented control algorithms produce results similar to those of stationary robots and much better results than conventional techniques. This work presents novel and innovative algorithms, which work robustly, accurately, and open up new opportunities for orthopedic interventions.

Dynamic Modeling of Shoulder Girdle Range of Motion Limits

2007 ◽  
Author(s):  
Brian A. Garner
Keyword(s):  
Range Of Motion ◽  
Degrees Of Freedom ◽  
Joint Angle ◽  
Shoulder Girdle ◽  
Musculoskeletal Modeling ◽  
Multiple Degrees Of Freedom ◽  
Joint Range Of Motion ◽  
Complex Approach ◽  
Joint Range ◽  
Flexion And Extension

For some applications of musculoskeletal modeling it may be important to simulate the passive responses of joint range-of-motion limits. For example, Lemay and Crago [1] enforced dynamic limits of flexion and extension in an elbow model. In cases such as the elbow where the joint can be modeled as a simple hinge, the range of motion can be easily specified in terms of a minimum and maximum joint angle, and the motion limits can be enforced using simple visco-elastic restraining torques against any limit violations. For joints such as the shoulder girdle, however, which involve multiple articulating bones and multiple degrees of freedom, dynamic enforcement of joint range-of-motion limits requires a more complex approach.

Development of an end-effector device for loose body removal in hip arthroscopy

2018 ◽  
Vol 232 (10) ◽  
pp. 987-998
Author(s):  
Chulmin Park ◽  
Shinsuk Park ◽  
Hanpyo Hong ◽  
In-Ho Jeon ◽  
Keri Kim
Keyword(s):  
Range Of Motion ◽  
Hip Arthroscopy ◽  
Degrees Of Freedom ◽  
Wrist Joint ◽  
Loose Body ◽  
Outer Diameter ◽  
Lateral Stiffness ◽  
End Effector ◽  
Material Stiffness ◽  
High Degree

This article describes a novel hand-operated end-effector device developed for loose body removal in hip arthroscopy. This sterilizable and reusable device incorporates a wire-ball joint mechanism that provides motion with 5 degrees of freedom. The design accounted for the following: (1) the diameter of the femoral head, (2) range of motion of the wrist joint of the operator, (3) ease of assembly of modular parts, and (4) material stiffness and durability. The developed device is composed of three parts: a pistol-shaped hand-held unit, forceps module, and end-effector module, all of which were constructed using polyamide-imide. Experiments were conducted to characterize the range of motion, pushing force, and lateral stiffness of the end-effector. Seven consulting surgeons evaluated the performance of the device in arthroscopic hip model and cadaveric studies in comparison with that of a conventional linear grasper. The experimental results show that the developed device can perform tasks that conventional linear graspers cannot. A specialized end-effector device was developed for hip arthroscopy where a high degree of stiffness is required. The end-effector module is interchangeable based on the required outer diameter, and it is also reusable after sterilization at high temperature.

scholarly journals Redundancy Resolution Using Tractrix—Simulations and Experiments

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
V. C. Ravi ◽  
Subrata Rakshit ◽  
Ashitava Ghosal
Keyword(s):  
Degrees Of Freedom ◽  
Redundancy Resolution ◽  
Redundant Manipulator ◽  
End Effector ◽  
Redundant Robots ◽  
Natural Motion ◽  
Fixed Base ◽  
Effective Use ◽  
Actuated Joints ◽  
Present Simulation

Hyper-redundant robots are characterized by the presence of a large number of actuated joints, a lot more than the number required to perform a given task. These robots have been proposed and used for many applications involving avoiding obstacles or, in general, to provide enhanced dexterity in performing tasks. Making effective use of the extra degrees-of-freedom or resolution of redundancy has been an extensive topic of research and several methods have been proposed in literature. In this paper, we compare three known methods and show that an algorithm based on a classical curve, called the tractrix, leads to a more “natural” motion of the hyper-redundant robot with the displacements diminishing from the end-effector to the fixed base. In addition, since the actuators nearer the base “see” a greater inertia due to the links farther away, smaller motion of the actuators nearer the base results in better motion of the end-effector as compared with other two approaches. We present simulation and experimental results performed on a prototype eight-link planar hyper-redundant manipulator.

scholarly journals Finite-Horizon Kinetic Energy Optimization of a Redundant Space Manipulator

2021 ◽  
Vol 11 (5) ◽  
pp. 2346
Author(s):  
Alessandro Tringali ◽  
Silvio Cocuzza
Keyword(s):  
Kinetic Energy ◽  
Real Time ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Computational Time ◽  
Redundant Manipulators ◽  
Space Robotics ◽  
Optimal Method ◽  
End Effector ◽  
Global Optimal

The minimization of energy consumption is of the utmost importance in space robotics. For redundant manipulators tracking a desired end-effector trajectory, most of the proposed solutions are based on locally optimal inverse kinematics methods. On the one hand, these methods are suitable for real-time implementation; nevertheless, on the other hand, they often provide solutions quite far from the globally optimal one and, moreover, are prone to singularities. In this paper, a novel inverse kinematics method for redundant manipulators is presented, which overcomes the above mentioned issues and is suitable for real-time implementation. The proposed method is based on the optimization of the kinetic energy integral on a limited subset of future end-effector path points, making the manipulator joints to move in the direction of minimum kinetic energy. The proposed method is tested by simulation of a three degrees of freedom (DOF) planar manipulator in a number of test cases, and its performance is compared to the classical pseudoinverse solution and to a global optimal method. The proposed method outperforms the pseudoinverse-based one and proves to be able to avoid singularities. Furthermore, it provides a solution very close to the global optimal one with a much lower computational time, which is compatible for real-time implementation.

A Hybrid Self-Stressed Cable-Driven Mechanism

2008 ◽  
Author(s):  
Saeed Behzadipour
Keyword(s):  
Static Loading ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Tensile Force ◽  
Cable System ◽  
End Effector ◽  
Stiffness Analysis ◽  
Cable Length ◽  
Cable Drive ◽  
Forward And Inverse Kinematics

A new hybrid cable-driven manipulator is introduced. The manipulator is composed of a Cartesian mechanism to provide three translational degrees of freedom and a cable system to drive the mechanism. The end-effector is driven by three rotational motors through the cables. The cable drive system in this mechanism is self-stressed meaning that the pre-tension of the cables which keep them taut is provided internally. In other words, no redundant actuator or external force is required to maintain the tensile force in the cables. This simplifies the operation of the mechanism by reducing the number of actuators and also avoids their continuous static loading. It also eliminates the redundant work of the actuators which is usually present in cable-driven mechanisms. Forward and inverse kinematics problems are solved and shown to have explicit solutions. Static and stiffness analysis are also performed. The effects of the cable’s compliance on the stiffness of the mechanism is modeled and presented by a characteristic cable length. The characteristic cable length is calculated and analyzed in representative locations of the workspace.

Kinematics of a Fully-Decoupled Remote Center-of-Motion Parallel Manipulator for Minimally Invasive Surgery

2012 ◽  
Vol 6 (2) ◽  
Author(s):  
Chin-Hsing Kuo ◽  
Jian S. Dai
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Surgical Instruments ◽  
End Effector ◽  
Minimally Invasive Surgical ◽  
Inverse Kinematics Problem

A crucial design challenge in minimally invasive surgical (MIS) robots is the provision of a fully decoupled four degrees-of-freedom (4-DOF) remote center-of-motion (RCM) for surgical instruments. In this paper, we present a new parallel manipulator that can generate a 4-DOF RCM over its end-effector and these four DOFs are fully decoupled, i.e., each of them can be independently controlled by one corresponding actuated joint. First, we revisit the remote center-of-motion for MIS robots and introduce a projective displacement representation for coping with this special kinematics. Next, we present the proposed new parallel manipulator structure and study its geometry and motion decouplebility. Accordingly, we solve the inverse kinematics problem by taking the advantage of motion decouplebility. Then, via the screw system approach, we carry out the Jacobian analysis for the manipulator, by which the singular configurations are identified. Finally, we analyze the reachable and collision-free workspaces of the proposed manipulator and conclude the feasibility of this manipulator for the application in minimally invasive surgery.

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