“…The table in Figure 9 shows the constraints among DH parameters in a Bricard mechanism in which a i is the length of link i + 1, α i is the twist angle between the axes of joints i and i + 1, d i is the offset distance at joint i, and θ i is the joint rotation angle for i=1,…6. It is known that the offset distances, twist angles, and link lengths in the opposite side of this mechanism must be equal 48 resulting in θ4=±θ1,θ5=±θ2,θ6=±θ3. Figure 8.A serial chain, its joints axes and desired poses.Figure 9.The Bricard mechanism with its DH parameters and dimensions.…”
Section: An Example Of Exoskeleton Design For Thumb Motionsmentioning
confidence: 99%
“…6. It is known that the offset distances, twist angles, and link lengths in the opposite side of this mechanism must be equal 48 resulting…”
Introduction
This study is aimed at developing a task-based methodology for the design of
robotic exoskeletons. This is in contrast to prevailing research efforts,
which attempt to mimic the human limb, where each human joint is given an
exoskeleton counter-joint. Rather, we present an alternative systematic
design approach for the design of exoskeletons that can follow the complex
three-dimensional motions of the human body independent of anatomical
measures and landmarks. With this approach, it is not necessary to know the
geometry of the targeted limb but rather to have a description of its motion
at the point of attachment.
Methods
The desired trajectory of the targeted limb has been collected through a
motion capture system from a healthy subject. Then, an approximate
dimensional synthesis has been employed to specify the size of the mechanism
and its location with respect to the limb, while generating the desired
trajectory. The procedure for this method, from motion capture to kinematic
synthesis to mechanism selection and optimization, is validated with an
illustrative example.
Results
The proposed method resulted an exoskeleton which follows the desired
trajectory of the human limb without any need of aligning its joint to the
corresponding human joints.
Conclusion
A method to design lower mobility exoskeletons for specific sets of human
motion is presented; the approach result an exoskeleton with lesser
actuation system while generating complex 3D limb motions, which in turn
results a lighter exoskeletons. It also avoids a need to align each robotic
joint axis with its human counterpart.
“…The table in Figure 9 shows the constraints among DH parameters in a Bricard mechanism in which a i is the length of link i + 1, α i is the twist angle between the axes of joints i and i + 1, d i is the offset distance at joint i, and θ i is the joint rotation angle for i=1,…6. It is known that the offset distances, twist angles, and link lengths in the opposite side of this mechanism must be equal 48 resulting in θ4=±θ1,θ5=±θ2,θ6=±θ3. Figure 8.A serial chain, its joints axes and desired poses.Figure 9.The Bricard mechanism with its DH parameters and dimensions.…”
Section: An Example Of Exoskeleton Design For Thumb Motionsmentioning
confidence: 99%
“…6. It is known that the offset distances, twist angles, and link lengths in the opposite side of this mechanism must be equal 48 resulting…”
Introduction
This study is aimed at developing a task-based methodology for the design of
robotic exoskeletons. This is in contrast to prevailing research efforts,
which attempt to mimic the human limb, where each human joint is given an
exoskeleton counter-joint. Rather, we present an alternative systematic
design approach for the design of exoskeletons that can follow the complex
three-dimensional motions of the human body independent of anatomical
measures and landmarks. With this approach, it is not necessary to know the
geometry of the targeted limb but rather to have a description of its motion
at the point of attachment.
Methods
The desired trajectory of the targeted limb has been collected through a
motion capture system from a healthy subject. Then, an approximate
dimensional synthesis has been employed to specify the size of the mechanism
and its location with respect to the limb, while generating the desired
trajectory. The procedure for this method, from motion capture to kinematic
synthesis to mechanism selection and optimization, is validated with an
illustrative example.
Results
The proposed method resulted an exoskeleton which follows the desired
trajectory of the human limb without any need of aligning its joint to the
corresponding human joints.
Conclusion
A method to design lower mobility exoskeletons for specific sets of human
motion is presented; the approach result an exoskeleton with lesser
actuation system while generating complex 3D limb motions, which in turn
results a lighter exoskeletons. It also avoids a need to align each robotic
joint axis with its human counterpart.
“…1a) is well-constrained, i.e. immobile [Chai & Chen (2010)], corresponding to a 0-dim submanifold. The 6R linkage can also be assembled to the line-symmetric Bricard mechanism in fig.…”
Section: Constraints Configuration Space and Mobilitymentioning
The paper revisits the definition and the identification of the singularities of kinematic chains and mechanisms. The degeneracy of the kinematics of an articulated system of rigid bodies cannot always be identified with the singularities of the configuration space. Local analysis can help identify kinematic chain singularities and better understand the way the motion characteristics change at such configurations. An example is shown that exhibits a kinematic singularity although its configuration space is a smooth manifold.
“…The spatial six‐link mechanisms are typical over constrained mechanisms which have been investigated in depth. The study of the spatial six‐link mechanisms including the 3R2PC (Peisach, 2005), 3R3P (Mavroidis and Roth, 1994), 4RPC (Yuan, 1971; Duffy and Rooney, 1974a, b, c), 4R2P (Jin and Yang, 2002; Mavroidis and Roth, 1994; Roth, 1995), 5RP (Mavroidis and Roth, 1994; Roth, 1995), 5RC (Duffy and Rooney, 1974d; Ju and Duffy, 1985) and 6R (Jin and Yang, 2002; Mavroidis and Roth, 1994; Baker, 2002; Chai and Chen, 2010; Chen and You, 2008a, b, 2009; Shih, 2002; Chen and Baker, 2005; Gan and Pellegrino, 2006; Chen et al , 2005; Lee and Yan, 1993; Brát, 1969; Yu, 1980) mechanisms is mainly concentrated on the synthesis and displacement analyses. Some of them are already used successfully.…”
PurposeThe purpose of this paper is to propose a spatial six‐link RRCCRR (where R denotes a revolute joint, and C denotes a cylindric joint) mechanism to be used as the mechanism body of a biped robot with three translations (3T) manipulation ability.Design/methodology/approachThis biped RRCCRR mechanism can reach any position on the ground by a crawling mode or alternatively, a somersaulting mode. After the robot reaches a designated position, it can work in manipulation mode. Mobility, walking mode, kinematic and stability analyses are performed, respectively.FindingsBased on this biped RRCCRR mechanism, a biped 3T lifter which can be used in industry is designed and analyzed. Finally, the proposed concept is verified by experiments on a prototype.Originality/valueThe work presented in this paper is one of new explorations to apply traditional spatial linkage mechanisms to the field of biped robots, and is also a new attempt to use the biped robot, that is generally used in the field of bionic robots, as a mobile manipulator robot platform in industry.
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