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.

Dynamic Performance Limitations Due to Yielding in Cable-Driven Robotic Manipulators

2005 ◽  
Vol 128 (1) ◽  
pp. 311-318 ◽  
Author(s):  
Xiaolei Yin ◽  
Alan P. Bowling
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Performance ◽  
Robotic Manipulators ◽  
Comprehensive Description ◽  
Body Model ◽  
Kinematic Coupling ◽  
Rigid Body Model ◽  
Torque Capacity ◽  
Reaction Forces ◽  
Performance Limitations

This paper presents a method for characterizing the performance limitations imposed by the yielding of the cables in systems with cable-driven transmissions. The method involves developing a rigid-body model of the system, where the cable tensions are considered as reaction forces. The kinematic coupling between links in the mechanism due to the use of cables is also considered. Here, the limitations on dynamic performance caused by cable yielding are added to the limitations caused by the bounds on actuator torque capacity, in order to give a more comprehensive description of the system’s capabilities. A two degrees-of-freedom planar mechanism is analyzed in order to illustrate the methodology.

Design of a Human-Like Range of Motion Hip Joint for Humanoid Robots

2014 ◽  
Author(s):  
Bryce Lee ◽  
Coleman Knabe ◽  
Viktor Orekhov ◽  
Dennis Hong
Keyword(s):  
Range Of Motion ◽  
Hip Joint ◽  
Disaster Response ◽  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Large Range ◽  
Humanoid Robots ◽  
Linkage Mechanism ◽  
Joint Torques ◽  
Similar Range

For a humanoid robot to have the versatility of humans, it needs to have similar motion capabilities. This paper presents the design of the hip joint of the Tactical Hazardous Operations Robot (THOR), which was created to perform disaster response duties in human-structured environments. The lower body of THOR was designed to have a similar range of motion to the average human. To accommodate the large range of motion requirements of the hip, it was divided into a parallel-actuated universal joint and a linkage-driven pin joint. The yaw and roll degrees of freedom are driven cooperatively by a pair of parallel series elastic linear actuators to provide high joint torques and low leg inertia. In yaw, the left hip can produce a peak of 115.02 [Nm] of torque with a range of motion of −20° to 45°. In roll, it can produce a peak of 174.72 [Nm] of torque with a range of motion of −30° to 45°. The pitch degree of freedom uses a Hoeken’s linkage mechanism to produce 100 [Nm] of torque with a range of motion of −120° to 30°.

Design of a Robotic Gripper Based on a Psittacus Erithacu Beak

2012 ◽  
Author(s):  
Alex W. Grammar ◽  
Robert L. Williams
Keyword(s):  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Large Range ◽  
Robotic Manipulators ◽  
African Grey Parrot ◽  
Beak Shape ◽  
Grey Parrot ◽  
Low Degrees ◽  
Application Specific ◽  
Single Part

A high versatility, low degrees-of-freedom (DOF) gripper was designed based on avian morphology. Grasping mechanisms for robotic manipulators are often developed for application-specific tasks, such as manipulating a single part or performing a repetitive action. In contrast, more dexterous grippers are complex, multiple-DOF mechanisms. A simple, minimal-DOF, versatile gripper has been developed based on the morphology of the Psittacus Erithacu (African Grey Parrot) beak shape. This species is highly intelligent and uses its beak for digging, gripping, climbing, and foraging. Giving a robot a similar capability would allow the platform to pick up targets such as single, small seeds, liquids, large irregular rocks and soft Robocup style balls. By using the beak as a model for a grasping mechanism the design maintains its versatility without the need for a complex system and allows a large range of targets to be gripped. This gripper is intended for use in the new open-source humanoid robot DARwIn-OP.

scholarly journals Software Sensor to Enhance Online Parametric Identification for Nonlinear Closed-Loop Systems for Robotic Applications

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3653
Author(s):  
Lilia Sidhom ◽  
Ines Chihi ◽  
Ernest Nlandu Kamavuako
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Parametric Identification ◽  
Recursive Least Squares ◽  
Unknown Parameters ◽  
Closed Loop Identification ◽  
Input Variables ◽  
Robotic Applications

This paper proposes an online direct closed-loop identification method based on a new dynamic sliding mode technique for robotic applications. The estimated parameters are obtained by minimizing the prediction error with respect to the vector of unknown parameters. The estimation step requires knowledge of the actual input and output of the system, as well as the successive estimate of the output derivatives. Therefore, a special robust differentiator based on higher-order sliding modes with a dynamic gain is defined. A proof of convergence is given for the robust differentiator. The dynamic parameters are estimated using the recursive least squares algorithm by the solution of a system model that is obtained from sampled positions along the closed-loop trajectory. An experimental validation is given for a 2 Degrees Of Freedom (2-DOF) robot manipulator, where direct and cross-validations are carried out. A comparative analysis is detailed to evaluate the algorithm’s effectiveness and reliability. Its performance is demonstrated by a better-quality torque prediction compared to other differentiators recently proposed in the literature. The experimental results highlight that the differentiator design strongly influences the online parametric identification and, thus, the prediction of system input variables.

On the Theory of the Calculation of the Constant Velocity Ball Transmission Joints

1976 ◽  
Vol 98 (3) ◽  
pp. 852-857 ◽  
Author(s):  
N. Bellomo
Keyword(s):  
Working Conditions ◽  
Load Distribution ◽  
Constant Velocity ◽  
Numerical Calculations ◽  
Torque Capacity ◽  
Safe Working ◽  
General Method

In this work a general method for the calculation of constant velocity ball transmission joint with straight grooves is studied. Numerical calculations concerning the forces transmitted by each driving ball and the torque capacity have been realized with reference to known and manufactured types of joint. The study allows one to deduce some important and experimentally confirmed designing rules and gives a precise picture of the load distribution in the joint as well as the limits of safe working conditions.

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 Planning Fail-Safe Trajectories for Space Robotic Arms

2021 ◽  
Vol 8 ◽  
Author(s):  
Oliver Porges ◽  
Daniel Leidner ◽  
Máximo A. Roa
Keyword(s):  
Degrees Of Freedom ◽  
Fault Tolerant ◽  
Robotic Manipulators ◽  
Task Completion ◽  
Joint Failure ◽  
Space Applications ◽  
Robotic Arms ◽  
Hazardous Environments ◽  
Potential Risks ◽  
Fail Safe

A frequent concern for robot manipulators deployed in dangerous and hazardous environments for humans is the reliability of task executions in the event of a joint failure. A redundant robotic manipulator can be used to mitigate the risk and guarantee a post-failure task completion, which is critical for instance for space applications. This paper describes methods to analyze potential risks due to a joint failure, and introduces tools for fault-tolerant task design and path planning for robotic manipulators. The presented methods are based on off-line precomputed workspace models. The methods are general enough to cope with robots with any type of joint (revolute or prismatic) and any number of degrees of freedom, and might include arbitrarily shaped obstacles in the process, without resorting to simplified models. Application examples illustrate the potential of the approach.

A Robotic Cell for Embedding Prefabricated Components in Extrusion-Based Additive Manufacturing

2020 ◽  
Author(s):  
Yeo Jung Yoon ◽  
Oswin G. Almeida ◽  
Aniruddha V. Shembekar ◽  
Satyandra K. Gupta
Keyword(s):  
Additive Manufacturing ◽  
Degrees Of Freedom ◽  
Robotic Manipulators ◽  
The Other ◽  
Robotic Arm ◽  
Robotic Cell ◽  
Material Extrusion ◽  
Surface Polishing ◽  
Pick And Place ◽  
6 Degrees Of Freedom

Abstract By attaching a material extrusion system to a robotic arm, we can deposit materials onto complex surfaces. Robotic manipulators can also maximize the task utility by performing other tasks such as assembly or surface polishing when they are not in use for the AM process. We present a robotic cell for embedding prefabricated components in extrusion-based AM. The robotic cell consists of two 6 degrees of freedom (DOF) robots, an extrusion system, and a gripper. One robot is used for printing a part, and the other robot takes a support role to pick and place the prefabricated component and embed it into the part being printed. After the component is embedded, AM process resumes, and the material is deposited onto the prefabricated components and previously printed layers. We illustrate the capabilities of the system by fabricating three objects.

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