Addition of Springs and its Impact on Cable-Driven Serial Manipulators

2014 ◽  
Author(s):  
Qingjuan Duan ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Range Of Motion ◽  
Performance Characteristics ◽  
Serial Manipulators ◽  
Placement And Routing ◽  
Multi Body

Serial multi-body systems can be driven by cables routed through the links to achieve the desired range of motion. Placement and routing of the cables alter the performance characteristics of the manipulator. There are possible applications for such mechanisms where low moving inertia is required. One of the challenges in the design of cable-driven mechanisms is to keep cables in tension during the motion. In this article, the addition of springs and its impact on workspace is investigated. A 2-link cable-driven robot is used to illustrate changes in Wrench Feasible Workspace (WFW) as springs are added between the serial manipulator and the ground or between the links.

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.

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.

Statics Analysis of Clemen’s Linkage for Robotic Applications

2013 ◽  
Author(s):  
Derek Lahr ◽  
Dennis Hong
Keyword(s):  
Range Of Motion ◽  
Constant Velocity ◽  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Robotic Manipulators ◽  
Electromechanical Actuators ◽  
Serial Manipulators ◽  
Torque Capacity ◽  
Multiple Actuators ◽  
Robotic Applications

Robotic manipulators can be categorized as either parallel, serial, or in some cases a combination of the two. Among others, a notable drawback of serial manipulators in dynamic applications is the large inertia created by typically heavy electromechanical actuators at the distal end of the manipulator. In addition, compact packaging of multiple actuators in a multi-degree of freedom (DOF) joint, as is often necessary with serial manipulators, can be difficult. These difficulties can be alleviated should a means be found to relocate actuators across one or more degrees of freedom. In this paper, we investigate a constant velocity (CV) linkage, the Clemen’s linkage, that may be used to relocate an actuator across a one DOF revolute joint to an adjacent link while maintaining a serially actuated architecture. This can be very advantageous in some applications such as a humanoid robot ankle. The linkage is analyzed for both its range of motion and torque capacity for such applications given limitations of currently available bearing hardware.

Impairment Tutorial: Recurrent Radioculpathy: Recurrent Radioculpathy and Apportionment

2002 ◽  
Vol 7 (4) ◽  
pp. 8-10
Author(s):  
Christopher R. Brigham ◽  
Leon H. Ensalada
Keyword(s):  
Lumbar Spine ◽  
Range Of Motion ◽  
Disk Herniation ◽  
Fourth Edition ◽  
Recurrent Injury ◽  
Injury Model ◽  
Whole Person ◽  
Spinal Region

Abstract Recurrent radiculopathy is evaluated by a different approach in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, compared to that in the Fourth Edition. The AMA Guides, Fifth Edition, specifies several occasions on which the range-of-motion (ROM), not the Diagnosis-related estimates (DRE) method, is used to rate spinal impairments. For example, the AMA Guides, Fifth Edition, clarifies that ROM is used only for radiculopathy caused by a recurrent injury, including when there is new (recurrent) disk herniation or a recurrent injury in the same spinal region. In the AMA Guides, Fourth Edition, radiculopathy was rated using the Injury Model, which is termed the DRE method in the Fifth Edition. Also, in the Fourth Edition, for the lumbar spine all radiculopathies resulted in the same impairment (10% whole person permanent impairment), based on that edition's philosophy that radiculopathy is not quantifiable and, once present, is permanent. A rating of recurrent radiculopathy suggests the presence of a previous impairment rating and may require apportionment, which is the process of allocating causation among two or more factors that caused or significantly contributed to an injury and resulting impairment. A case example shows the divergent results following evaluation using the Injury Model (Fourth Edition) and the ROM Method (Fifth Edition) and concludes that revisions to the latter for rating permanent impairments of the spine often will lead to different results compared to using the Fourth Edition.

Spinal Impairment Evaluation: Fifth Edition Changes

2001 ◽  
Vol 6 (1) ◽  
pp. 1-3
Author(s):  
Robert H. Haralson
Keyword(s):  
Spinal Cord ◽  
Lower Extremity ◽  
Range Of Motion ◽  
Upper Extremity ◽  
Spinal Cord Injuries ◽  
Clinical Findings ◽  
Fourth Edition ◽  
Treatment Results ◽  
Standard Terminology ◽  
Made In

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, was published in November 2000 and contains major changes from its predecessor. In the Fourth Edition, all musculoskeletal evaluation and rating was described in a single chapter. In the Fifth Edition, this information has been divided into three separate chapters: Upper Extremity (13), Lower Extremity (14), and Spine (15). This article discusses changes in the spine chapter. The Models for rating spinal impairment now are called Methods. The AMA Guides, Fifth Edition, has reverted to standard terminology for spinal regions in the Diagnosis-related estimates (DRE) Method, and both it and the Range of Motion (ROM) Method now reference cervical, thoracic, and lumbar. Also, the language requiring the use of the DRE, rather than the ROM Method has been strengthened. The biggest change in the DRE Method is that evaluation should include the treatment results. Unfortunately, the Fourth Edition's philosophy regarding when and how to rate impairment using the DRE Model led to a number of problems, including the same rating of all patients with radiculopathy despite some true differences in outcomes. The term differentiator was abandoned and replaced with clinical findings. Significant changes were made in evaluation of patients with spinal cord injuries, and evaluators should become familiar with these and other changes in the Fifth Edition.

Osteosynthesis of Combined Injuries of the Capitellum humeri and the Radial Head

Swiss Surgery ◽  
2003 ◽  
Vol 9 (6) ◽  
pp. 275-282
Author(s):  
Ott ◽  
Rikli ◽  
Babst
Keyword(s):  
Range Of Motion ◽  
Radial Head ◽  
Performance Score ◽  
Anatomische Rekonstruktion ◽  
Mayo Elbow Performance Score ◽  
Capitulum Humeri ◽  
Combined Injuries

Einleitung: Kombinierte Verletzungen des Capitulum humeri und des Radiusköpfchens sind selten. Meist sind neben den osteocartilaginären Schäden am Gelenk auch Verletzungen der Kollateralbänder assoziiert. Behandlungsempfehlungen für diese seltenen schwerwiegenden Ellenbogenverletzungen fehlen. Studientyp: In einer retrospektiven Analyse werden fünf Fälle untersucht, bei denen die osteocartilaginären Verletzungen des Capitulum humeri durch den gleichen Zugang, der zur Versorgung des Radiusköpfchens verwendet wurde, versorgt wurden. Die Osteosynthese erfolgte mit Mini-Titanimplantaten z.T. kombiniert mit resorbierbaren Pins. Patienten und Methode: Zwischen 1996-1999 wurden fünf Patienten (vier Männer, eine Frau) mit einer Kombinationsverletzung von Radiuskopf und Capitulum humeri operativ stabilisiert. Das Durchschnittsalter beträgt 34 Jahre (31-40 Jahre). Alle Frakturen wurden über einen direkten radialen Zugang mittels 1.5mm oder 2.0mm Zugschrauben, zum Teil mit resorbierbaren Pins stabilisiert. Anschliessend wurden die Patienten radiologisch und klinisch gemäss dem Mayo-elbow-performance Score beurteilt. Resultate: Alle Patienten konnten persönlich durch einen nicht in die Initialtherapie involvierten Untersucher nach durchschnittlich 12.8 Monaten (8-24 Monate) nachuntersucht werden. 4/5 Patienten konnten bezüglich ihrer subjektiven Einschätzung befragt werden. Radiologische Zeichen einer Nekrose des Capitulum humeri oder Arthrosezeichen fanden sich nicht. Bei drei Patienten fanden sich periartikuläre Verkalkungen. Der range of motion beträgt durchschnittlich 124 Grad (Extension 5-30 Grad, Flexion 110-145 Grad) in drei von fünf Fällen waren Sekundäreingriffe zu Mobilitätsverbesserung nötig. Der Mayo-elbow-performance Score beträgt im Mittel 85 Punkte (range 70-100 Punkte). Schlussfolgerung: Die direkte Verschraubung mit Miniimplantaten zum Teil in Kombination mit resorbierbaren Pins ermöglicht eine stabile anatomische Rekonstruktion des Capitulum humeri durch den gleichen Zugang wie er für die Stabilisierung des Radiusköpfchens notwendig ist. Die transartikuläre Fixation der kleinen Schalenfragmente des Capitulum humeri erlaubt eine sichere interfragmentäre Kompression und damit eine frühfunktionelle Rehabilitation. Sekundäreingriffe zur Verbesserung der Gelenkbeweglichkeit waren in drei von fünf Fällen nötig.

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