Positional kinematics of humanoid arms

Robotica ◽  
2005 ◽  
Vol 24 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Jadran Lenarčič ◽  
Nives Klopčar
Keyword(s):  
Shoulder Joint ◽  
Glenohumeral Joint ◽  
Humanoid Robots ◽  
Optical Measurements ◽  
Constant Length ◽  
Human Arm ◽  
Joint Coordinates ◽  
Healthy Female ◽  
Shoulder Complex ◽  
And Control

We present the positional abilities of a humanoid manipulator based on an improved kinematical model of the human arm. This was synthesized from electro-optical measurements of healthy female and male subjects. The model possesses three joints: inner shoulder joint, outer shoulder joint and elbow joint. The first functions as the human sternoclavicular joint, the second functions as the human glenohumeral joint, and the last replicates the human humeroulnar rotation. There are three links included, the forearm and the upper arm link which are of a constant length, and the shoulder link which is expandable. Mathematical interrelations between the joint coordinates are also taken into consideration. We determined the reachability of a humanoid arm, treated its orienting redundancy in the shoulder complex and the positional redundancy in the shoulder-elbow complexes, and discussed optimum configurations in executing different tasks. The results are important for the design and control of humanoid robots, in medicine and sports.

A KINEMATIC MODEL OF THE UPPER LIMB WITH A CLAVICLE-LIKE LINK FOR HUMANOID ROBOTS

2008 ◽  
Vol 05 (01) ◽  
pp. 87-118 ◽  
Author(s):  
BERTRAND TONDU
Keyword(s):  
Upper Limb ◽  
Humanoid Robot ◽  
Frontal Zone ◽  
Kinematic Model ◽  
Shoulder Girdle ◽  
Humanoid Robots ◽  
Biomechanical Study ◽  
The Body ◽  
Human Arm ◽  
Shoulder Complex

Starting from a biomechanical study of the shoulder complex, the relevance of a serial nine d.o.f. kinematic model of the human arm, including a clavicle-like link, was analyzed. It is shown that this partial biomimetic joint model of the upper limb is able to mimic the ability of the natural arm to practically eliminate internal and bound singularities over a large frontal zone, so as to maintain its elbow laterally to the body. In this sense, it appears to be an advanced solution for increasing the dexterity of humanoid robot upper limbs, thus replacing classical seven d.o.f. anthropomorphic arms where a device mimicking the shoulder girdle mechanism is absent.

scholarly journals Errors in Shoulder Joint Position Sense Mainly Come from the Glenohumeral Joint

2017 ◽  
Vol 33 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Yin-Liang Lin ◽  
Andrew Karduna
Keyword(s):  
Shoulder Joint ◽  
Glenohumeral Joint ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Active Joint ◽  
Angle Effect ◽  
Shoulder Complex ◽  
Predictive Relationship ◽  
Scapular Plane

While synchronous movement of the glenohumeral and scapulothoracic joints has been emphasized in previous kinematics studies, most investigations of shoulder joint position sense have treated the shoulder complex as a single joint. The purposes of this study were to investigate the joint position sense errors of the humerothoracic, glenohumeral, and scapulothoracic joints at different elevation angles and to examine whether the errors of the glenohumeral and scapulothoracic joints contribute to the errors of the humerothoracic joint. Fifty-one subjects with healthy shoulders were recruited. Active joint position sense of the humerothoracic, glenohumeral, and scapulothoracic joints was measured at 50°, 70°, and 90° of humerothoracic elevation in the scapular plane. The results showed that while scapulothoracic joint position sense errors were not affected by target angles, there was an angle effect on humerothoracic and glenohumeral errors, with errors decreasing as the target angles approached 90° of elevation. The results of a multiple regression analysis revealed that glenohumeral errors explained most of the variance of the humerothoracic errors and that scapulothoracic errors had a weaker predictive relationship with humerothoracic errors. Therefore, it may be necessary to test scapular joint position sense separately in addition to the assessment of the overall shoulder joint position sense.

scholarly journals Cadaveric evaluation of the feasibility of glenohumeral joint denervation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Amr M. Aly
Keyword(s):  
Muscle Weakness ◽  
Shoulder Joint ◽  
Glenohumeral Joint ◽  
Axillary Nerve ◽  
Low Risk ◽  
Dorsal Approach ◽  
Articular Branch ◽  
Pectoral Nerve ◽  
Teres Minor

Abstract Purpose To assess the feasibility of total shoulder denervation through two proposed incisions. Methods Total shoulder denervation was performed through an extended delta-pectoral approach and a transverse dorsal approach at the spine of the scapula. The study involved six cadavers. Course and number of articular branches from the lateral pectoral, axillary and supra-scapular nerve were documented. Results All shoulder joint articular branches were accessible through the proposed anterior and posterior approaches. The articular branch of the lateral pectoral nerve and supra scapular nerve were present in all the specimen. Axillary nerve articular branches were variable in number but when present anteriorly were proximal to the deltoid muscular branches and posteriorly proximal to the muscular branches to the teres minor. Conclusion Total glenohumeral denervation was feasible through our proposed anterior and posterior approaches. Enhanced knowledge of articular nerve branches could provide interventional targets for joint and ligament pain, with low risk of muscle weakness.

scholarly journals Turning Gait Planning Method for Humanoid Robots

2018 ◽  
Vol 8 (8) ◽  
pp. 1257 ◽  
Author(s):  
Tianqi Yang ◽  
Weimin Zhang ◽  
Xuechao Chen ◽  
Zhangguo Yu ◽  
Libo Meng ◽  
...  
Keyword(s):  
Inverted Pendulum ◽  
Center Of Mass ◽  
Translational Motion ◽  
Humanoid Robots ◽  
Inverted Pendulum Model ◽  
Straight Line ◽  
Pendulum Model ◽  
The Stability ◽  
And Control ◽  
Present Simulation

The most important feature of this paper is to transform the complex motion of robot turning into a simple translational motion, thus simplifying the dynamic model. Compared with the method that generates a center of mass (COM) trajectory directly by the inverted pendulum model, this method is more precise. The non-inertial reference is introduced in the turning walk. This method can translate the turning walk into a straight-line walk when the inertial forces act on the robot. The dynamics of the robot model, called linear inverted pendulum (LIP), are changed and improved dynamics are derived to make them apply to the turning walk model. Then, we expend the new LIP model and control the zero moment point (ZMP) to guarantee the stability of the unstable parts of this model in order to generate a stable COM trajectory. We present simulation results for the improved LIP dynamics and verify the stability of the robot turning.

scholarly journals Optimal Design of a Bio-Inspired Anthropocentric Shoulder Rehabilitator

2006 ◽  
Vol 3 (3) ◽  
pp. 199-208 ◽  
Author(s):  
S. K. Mustafa ◽  
G. Yang ◽  
S. H. Yeo ◽  
W. Lin
Keyword(s):  
Performance Evaluation ◽  
Shoulder Joint ◽  
Stroke Rehabilitation ◽  
Design Methodology ◽  
Anatomical Structure ◽  
Robotic Arm ◽  
Analysis And Design ◽  
Non Invasive ◽  
Performance Requirements ◽  
Human Arm

This paper presents the design of a bio-inspired anthropocentric 7-DOF wearable robotic arm for the purpose of stroke rehabilitation. The proposed arm rehabilitator synergistically utilizes the human arm structure with non-invasive kinematically under-deterministic cable-driven mechanisms to form a completely deterministic structure. It offers the advantages of being lightweight and having high dexterity. Adopting an anthropocentric design concept also allows it to conform to the human anatomical structure. The focus of this paper is on the analysis and design of the 3-DOF-shoulder module, called the shoulder rehabilitator. The design methodology is divided into three main steps: (1) performance evaluation of the cable-driven shoulder rehabilitator, (2) performance requirements of the shoulder joint based on its physiological characteristics and (3) design optimization of the shoulder rehabilitator based on shoulder joint physiological limitations. The aim is to determine a suitable configuration for the development of a shoulder rehabilitator prototype.

Humanoid Robots and Control

2016 ◽  
pp. 15-47
Author(s):  
Adam Spiers ◽  
Said Ghani Khan ◽  
Guido Herrmann
Keyword(s):  
Humanoid Robots ◽  
And Control

Efficient Actor-Critic Reinforcement Learning With Embodiment of Muscle Tone for Posture Stabilization of the Human Arm

2021 ◽  
Vol 33 (1) ◽  
pp. 129-156
Author(s):  
Masami Iwamoto ◽  
Daichi Kato
Keyword(s):  
Reinforcement Learning ◽  
Muscle Tone ◽  
Muscle Tension ◽  
Experimental Studies ◽  
Control Policy ◽  
Humanoid Robots ◽  
Pedunculopontine Tegmental Nucleus ◽  
Learning Efficiency ◽  
Human Arm ◽  
Posture Stabilization

This letter proposes a new idea to improve learning efficiency in reinforcement learning (RL) with the actor-critic method used as a muscle controller for posture stabilization of the human arm. Actor-critic RL (ACRL) is used for simulations to realize posture controls in humans or robots using muscle tension control. However, it requires very high computational costs to acquire a better muscle control policy for desirable postures. For efficient ACRL, we focused on embodiment that is supposed to potentially achieve efficient controls in research fields of artificial intelligence or robotics. According to the neurophysiology of motion control obtained from experimental studies using animals or humans, the pedunculopontine tegmental nucleus (PPTn) induces muscle tone suppression, and the midbrain locomotor region (MLR) induces muscle tone promotion. PPTn and MLR modulate the activation levels of mutually antagonizing muscles such as flexors and extensors in a process through which control signals are translated from the substantia nigra reticulata to the brain stem. Therefore, we hypothesized that the PPTn and MLR could control muscle tone, that is, the maximum values of activation levels of mutually antagonizing muscles using different sigmoidal functions for each muscle; then we introduced antagonism function models (AFMs) of PPTn and MLR for individual muscles, incorporating the hypothesis into the process to determine the activation level of each muscle based on the output of the actor in ACRL. ACRL with AFMs representing the embodiment of muscle tone successfully achieved posture stabilization in five joint motions of the right arm of a human adult male under gravity in predetermined target angles at an earlier period of learning than the learning methods without AFMs. The results obtained from this study suggest that the introduction of embodiment of muscle tone can enhance learning efficiency in posture stabilization disorders of humans or humanoid robots.

scholarly journals Stress Distribution Patterns Across the Shoulder Joint in Gymnasts: A Computed Tomography Osteoabsorptiometry Study

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096210
Author(s):  
Daisuke Momma ◽  
Wataru Iwamoto ◽  
Kaori Endo ◽  
Kazuki Sato ◽  
Norimasa Iwasaki
Keyword(s):  
Bone Density ◽  
Stress Distribution ◽  
Distribution Pattern ◽  
Subchondral Bone ◽  
Shoulder Joint ◽  
Glenohumeral Joint ◽  
Articular Surface ◽  
Articular Surfaces ◽  
Subchondral Bone Density ◽  
Collegiate Gymnasts

Background: The distribution pattern of subchondral bone density is an indicator of stress distribution over a joint surface under long-term physiologic loading. The biomechanical characteristics of the articular surfaces of the shoulder joint in gymnasts can be determined by measuring this distribution pattern. Purpose: To evaluate the distribution of subchondral bone density across the shoulder joint in male collegiate gymnasts and to determine the effects of gymnastic activities on its articular surfaces under long-term loading conditions using computed tomography osteoabsorptiometry (CTOAM). Study Design: Descriptive laboratory study. Methods: CT image data were obtained from both shoulders of 12 asymptomatic male collegiate gymnasts (gymnast group; mean age, 19.4 years; range, 18-22 years) and 10 male collegiate volunteers (control group; mean age, 20.2 years; range, 18-22 years). The distribution pattern of subchondral bone density across the articular surfaces of each shoulder joint was assessed by CTOAM. Quantitative analysis was performed of the locations and percentages of high-density areas on the articular surface. Results: Stress distribution patterns over the articular surfaces differed between the gymnasts and the controls. In the gymnasts, high-density areas were detected on the posterosuperior articular surface of the humeral head and the anterosuperior and/or posterosuperior articular surface of the glenoid. Mean bone density was greater in the gymnasts than in the controls ( P < .0001). Conclusion: Stress distribution over the articular surfaces of the shoulder joint was affected by gymnastic activities. Stress was concentrated over the superior part of the glenohumeral joint in male collegiate gymnasts. Clinical Relevance: The present findings suggest that gymnastic activities increase stress to the articular surfaces of the superior glenohumeral joint. This supports the notion that mechanical conditions play a crucial role in the origin of disorders particular to gymnastic activities.

scholarly journals Anatomy and Biomechanic of the Shoulder

2019 ◽  
Vol 7 (11_suppl6) ◽  
pp. 2325967119S0046
Author(s):  
Troydimas Panjaitan
Keyword(s):  
Rotator Cuff ◽  
Humeral Head ◽  
Glenohumeral Joint ◽  
External Rotation ◽  
Central Component ◽  
Subscapularis Tendon ◽  
Glenoid Fossa ◽  
Greater Tuberosity ◽  
Glenohumeral Ligaments ◽  
Shoulder Complex

The shoulder is one of the most complex joints of the human body. Consequently, they are susceptible to injury and degeneration. Mechanical shoulder pathology typically results when overuse, extremes of motion, or excessive forces overwhelm intrinsic material properties of the shoulder complex resulting in tears of the rotator cuff, capsule, and labrum. The fundamental central component of the shoulder complex is the glenohumeral joint. It has a ball-and-socket configuration with a surface area ratio of the humeral head to glenoid fossa of about 3:1 with an appearance similar to a golf ball on a tee. Overall, there is minimal bony covering and limited contact areas that allow extensive translational and rotational ability in all three planes. The glenohumeral joint has 2 groups of stabilizers, which are static (passive) and dynamic (active) restrains. Static stabilizers include the concavity of the glenoid fossa, glenoid fossa retroversion and superior angulation, glenoid labrum, the joint capsule, and glenohumeral ligaments, and a vacuum effect from negative intra-articular pressure. Dynamic stabilization is merely the coordinated contraction of the rotator cuff muscles that create forces that compress the articular surfaces of the humeral head into the concave surface of the glenoid fossa. During upper extremity movement, the effects of static stabilizers are minimized and dynamic or active stabilizers become the dominant forces responsible for glenohumeral stability The simple act of arm elevation is a complex task that occurs via the combination of glenohumeral and scapulothoracic motion, together known as scapulohumeral rhythm. In the first 1200, glenohumeral arm abduction, the supraspinatus and deltoid work together and create a force couple that promotes stability, while raising the arm (deltoid contraction). In addition, the humerus must undergo 450 external rotation to not only clear the greater tuberosity posteriorly but also loosen the inferior glenohumeral ligament (IGHL) to allow maximum elevation. There are several anatomical updates regarding the rotator cuff and capsular footprint. The footprint of the supraspinatus on the greater tuberosity is much smaller than previously believed, and this area of the greater tuberosity is actually occupied by a substantial amount of the infraspinatus. The superior-most insertion of the subscapularis tendon extends a thin tendinous slip, which attaches to the fovea capitis of the humerus. The teres minor muscle inserts to the lowest impression of the greater tuberosity of the humerus and additionally inserts to the posterior side of the surgical neck of the humerus.

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