scholarly journals 1A1-H4 Learning of optimal joint stiffness of a tendon-driven robotic arm with GA

2001 ◽  
Vol 2001 (0) ◽  
pp. 13
Author(s):  
H. Kobayashi ◽  
N. Fujio ◽  
T. Yoshidome
Keyword(s):  
Joint Stiffness ◽  
Robotic Arm

Posture Control Considering Joint Stiffness of a Robotic Arm Driven by Rubberless Artificial Muscle

2016 ◽  
Vol 10 (4) ◽  
pp. 503-510 ◽  
Author(s):  
Naoki Saito ◽  
◽  
Toshiyuki Satoh ◽  
Keyword(s):  
Joint Angle ◽  
Joint Stiffness ◽  
Mathematical Expression ◽  
Artificial Muscle ◽  
Good Control ◽  
Robotic Arm ◽  
Rubber Tube ◽  
Robotic Arms ◽  
Control Scheme ◽  
The Relationship

This paper describes a joint angle control considering the passive joint stiffness of robotic arms driven by rubberless artificial muscle (RLAM), which is a pneumatic actuator. The contraction mechanism of RLAM is the same as that of the McKibben artificial muscle. Unlike the McKibben artificial muscle, RLAM is constructed using an airbag made of a nonelastic material instead of a rubber tube.The objective of this study is to realize a soft contact movement of robotic arms by applying the passive compliance characteristics of RLAMs. In this study, we derive a mathematical expression for the relationship between the output of an RLAM and the joint stiffness of a robotic arm. In addition, we suggest a control scheme for each RLAM. We confirm the validity of these suggestions experimentally. From the result, we observe a good control performance of the joint angle. A robotic arm moves smoothly according to the force added from outside by setting the passive stiffness of the arm.

scholarly journals On the elastodynamics of a five-axis lightweight anthropomorphic robotic arm

2021 ◽  
Author(s):  
Guanglei Wu
Keyword(s):  
Sensitivity Analysis ◽  
Joint Stiffness ◽  
Robotic Arm ◽  
Response Analysis ◽  
Modeling And Analysis ◽  
Robotic Arms ◽  
Linear Elastic ◽  
Small Influence ◽  
Elastodynamic Modeling ◽  
Five Axis

This paper presents elastodynamic modeling and analysis for a five-axis lightweight robotic arm. Natural frequencies are derived and visualized within the dexterous workspace to show the overall performances and compare them to the frequencies when the robotics is with payload. The comparison shows that the payload has a relatively small influence to the first- and second-order frequencies. Sensitivity analysis is conducted, and the system's frequency is more sensitive to the second joint stiffness than the others. Moreover, observations from the displacement response analysis reveal that the robotics produces linear elastic displacements of the same level between the loaded and unloaded working modes but larger rotational deflections under the loaded working condition. The main contribution of this work lies in that a systematic approach of elastodynamic analysis for serial robotic manipulators is formulated, where the arm gravity and external load are taken into account to investigate the dynamic behaviors of the robotic arms, i.e., frequencies, sensitivity analysis, and displacement responses, under the loaded mode.

Three-dimensional flexural-joint stiffness analysis of flexible manipulator arms

Robotica ◽  
1988 ◽  
Vol 6 (3) ◽  
pp. 203-212 ◽  
Author(s):  
A. Meghdari ◽  
M. Shahinpoor
Keyword(s):  
Stiffness Matrix ◽  
Three Dimensional ◽  
Joint Stiffness ◽  
Beam Theory ◽  
Flexible Manipulator ◽  
Robotic Arm ◽  
Flexible Robot ◽  
Stiffness Analysis ◽  
Stiffness Matrices ◽  
Stiffness Properties

SUMMARYThis paper presents a complete derivation of the combined flexural-joint stiffness matrix and the elastic deformation field of flexible manipulator arms treated in a three-dimensional fashion. The stiffness properties are derived directly from the differential equations used in the engineering beam theory. The expressions developed here can readily be used in the modeling, control and design of light weight flexible robot manipulators. A two-link arm is used to formulate these expressions and the results can be generalized to n–link manipulators. The stiffness matrix for a robotic link element in 3-D is of the order of 12 X 12, and for an n–link robotic arm the total elemental and system stiffness matrices will be of the order of the (12n X 12n) and 6(n + 1) X 6(n + 1), respectively.

scholarly journals Design and Control of an Inflatable Spherical Robotic Arm for Pick and Place Applications

Actuators ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 299
Author(s):  
Matthias Hofer ◽  
Jasan Zughaibi ◽  
Raffaello D’Andrea
Keyword(s):  
Lightweight Design ◽  
Joint Stiffness ◽  
Robotic Arm ◽  
Robot Arm ◽  
Allocation Strategy ◽  
Modeling And Control ◽  
Control Approach ◽  
Flow Capacity ◽  
Payload Mass ◽  
And Control

We present an inflatable soft robotic arm made of fabric that leverages state-of-the-art manufacturing techniques, leading to a robust and reliable manipulator. Three bellow-type actuators are used to control two rotational degrees of freedom, as well as the joint stiffness that is coupled to a longitudinal elongation of the movable link used to grasp objects. The design is motivated by a safety analysis based on first principles. It shows that the interaction forces during an unexpected collision are primarily caused by the attached payload mass, but can be reduced by a lightweight design of the robot arm. A control allocation strategy is employed that simplifies the modeling and control of the robot arm and we show that a particular property of the allocation strategy ensures equal usage of the actuators and valves. The modeling and control approach systematically incorporates the effect of changing joint stiffness and the presence of a payload mass. An investigation of the valve flow capacity reveals that a proper timescale separation between the pressure and arm dynamics is only given for sufficient flow capacity. Otherwise, the applied cascaded control approach can introduce oscillatory behavior, degrading the overall control performance. A closed form feed forward strategy is derived that compensates errors induced by the longitudinal elongation of the movable link and allows the realization of different object manipulation applications. In one of the applications, the robot arm hands an object over to a human, emphasizing the safety aspect of the soft robotic system. Thereby, the intrinsic compliance of the robot arm is leveraged to detect the time when the robot should release the object.

Monkeys move robotic arm using brain power

Nature ◽  
2008 ◽  
Author(s):  
Michael Hopkin
Keyword(s):  
Robotic Arm

Control Algorithm for an Industrial Robotic Arm Using Computer Vision

2015 ◽  
Vol 9 (2) ◽  
pp. 182
Author(s):  
Germán Buitrago Salazar ◽  
Olga Lucía Ramos ◽  
Dario Amaya
Keyword(s):  
Computer Vision ◽  
Control Algorithm ◽  
Robotic Arm

Forward Kinematic Analysis of JACO2 Robotic Arm Towards Implementing a Grapes Harvesting Robot

2020 ◽  
Author(s):  
Theodore Pachidis ◽  
Christos Sgouros ◽  
Vassilis G. Kaburlasos ◽  
Eleni Vrochidou ◽  
Theofanis Kalampokas ◽  
...  
Keyword(s):  
Kinematic Analysis ◽  
Robotic Arm ◽  
Forward Kinematic ◽  
Harvesting Robot

Controllable Compliance Joint For Human Oriented Robots

2013 ◽  
Vol 43 (1) ◽  
pp. 47-60
Author(s):  
Mihail Tsveov ◽  
Dimitar Chakarov
Keyword(s):  
Numerical Experiments ◽  
Position Control ◽  
Joint Stiffness ◽  
Joint Motion ◽  
Compliance Control ◽  
Leaf Springs ◽  
Antagonistic Actuation

Abstract In the paper, different approaches for compliance control for human oriented robots are revealed. The approaches based on the non- antagonistic and antagonistic actuation are compared. In addition, an approach is investigated in this work for the compliance and the position control in the joint by means of antagonistic actuation. It is based on the capability of the joint with torsion leaf springs to adjust its stiffness. Models of joint stiffness are presented in this paper with antagonistic and non-antagonistic influence of the spring forces on the joint motion. The stiffness and the position control possibilities are investigated and the opportunity for their decoupling as well. Some results of numerical experiments are presented in the paper too.

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