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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
where q(s) is the transfer function model of the open loop system, including the controller and the process in cascade. See also acceleration error constant and position error constant. velocity filtering means for discriminating signals from noise or other undesired signals because of their different apparent velocities. velocity flow field the velocity field calculated in optical flow computation. velocity manipulability ellipsoid an ellipsoid that characterizes the end-effector velocities that can be generated with the given set of joint velocities, with the manipulator in a given posture. Consider a set of generalized joint velocities q of constant, unit norm q T q = 1. Taking into account the differential kinematics J and properties of the pseudo-inverse of the geometrical Jacobian, the unit norm can be rewritten as follows: v T (J J T )-1 v = 1, which is the equation of the points on the surface of an ellipsoid in the endeffector velocity space. velocity of light in vacuum, a constant equal to 2.997928 × 108 meters/second. In other media, equal to the vacuum value divided by the refractive index of the medium. velocity saturation a physical process in a semiconductor where the carrier velocity becomes
A potential field based multi-axis printing path generation algorithm
Published in International Journal of Computer Integrated Manufacturing, 2020
Fubao Xie, Danjie Bi, Kai Tang
During a robotic multi-axis printing process, if the manipulator is near a singular configuration, even a very small change on the printing path may cause a huge and rapid motion of some joints, which is detrimental to the printing accuracy and susceptible to potential collision (Xiao and Huan 2012). The so-called manipulability ellipsoid is employed in this paper to evaluate the existence of singularity, which is well known for its efficacy of evaluating the kinematic quality of a serial robotic manipulator (Lynch, Kevin, and Park 2017; Yoshikawa 2003). In particular, one useful criterion derived from the manipulability ellipsoid is the parameter of singularity (PS) (Huo and Baron 2011). Mathematically, the PS can be expressed as
Evaluation of physical workload during work behavior for work environment design from biomechanical perspective: a case study in initial orientation selection of work object for manual handling tasks
Published in Theoretical Issues in Ergonomics Science, 2021
Akisue Kuramoto, Kazuki Hiranai, Akihiko Seo
To quantitatively represent workability, a few researchers have discussed the manipulability of an end-effector. Manipulability ellipsoid (Hanafusa, Yoshikawa, and Nakamura 1981) describes the ability to position and orient the end-effector. Dynamic manipulability ellipsoid (Yoshikawa 1985) or impedance matching ellipsoid (Kurazume and Hasegawa 2005a, 2005b) indicates the movement direction where the end-effector can output high torque or force transmission rates, considering the hand stiffness. However, these methods do not indicate the amount of physical workload on each part of the human body in the work behavior.
Posture evaluation for mobile manipulators using manipulation ability, tolerance on grasping, and pose error of end-effector
Published in Advanced Robotics, 2021
Satoshi Suzuki, Daisuke Endo, Kimitoshi Yamazaki
The final item can also be explained in terms of manipulability of the manipulator. For instance, a manipulability ellipsoid might form a long and thin shape when the manipulator is close to the singular pose. This fact serves as a rational reason to explain that a suitable evaluation can be obtained at positions that are intermediately distant from the target end-effector pose.