Showing papers in "Mechanism and Machine Theory in 1998"

TL;DR: In this paper, an inverse dynamic formulation by the Newton-Euler approach for the Stewart platform manipulator of the most general architecture and models all the dynamic and gravity effects as well as the viscous friction at the joints is presented.

TL;DR: In this paper, the design of underactuated mechanical hands is addressed and a robust mechanical hand capable of performing industrial tasks involving the grasping of a wide variety of objects with large forces is presented.

TL;DR: In this paper, the authors address the question of dynamic formulation of the six-degrees-of-freedom parallel manipulator known as the Stewart platform and derive the dynamic equations for the two widely used kinematic structures of the Stewart platforms through the Newton-Euler approach.

TL;DR: This paper presents geometrical algorithms for the determination of various workspaces of planar parallel manipulators and one of them is used to illustrate the algorithms.

TL;DR: In contrast to kinematic redundancy (widely studied in literature) in serial manipulators, the natural choice should be force (static) redundancy in parallel manipulators.

TL;DR: In this paper, a method for finding and classifying all the singularities of an arbitrary non-redundant mechanism is presented. But this method is based on the velocity-equation formulation of kinematic singularity and the singularity classification first introduced in (Zlatanov et al., 1994-1,2).

TL;DR: In this article, a new approach to solve the inverse kinematics problem of redundant robot manipulators in environments cluttered with obstacles is presented, where the physical problem is formulated as an optimization problem under constraints, and solved via a modified GA.

TL;DR: This paper addresses the problem of singularity-free path planning for the six-degree-of-freedom parallel manipulator known as the Stewart platform manipulator with an algorithm developed to construct continuous paths within the workspace of the manipulator by avoiding singularities and ill-conditioning.

TL;DR: In this article, the authors utilize a geometric model of the solution space to obtain analytical relationships between the link lengths of two-degree-of-freedom parallel planar manipulators and performance criteria based on the global conditioning and global velocity indices.

TL;DR: In this paper, the authors considered a solution to the problem of moving a robot manipulator with minimum cost along a specified geometric path, where the optimal traveling time and the minimum mechanical energy of the actuators were considered together to build a multi-objective function.

TL;DR: In this paper, two online singularity avoidance schemes are proposed to find an alternate path of the manipulator near singularity to keep the actuator forces always within their capacities, which is shown to yield a minimum deviation of the PPM from the specified path but it requires a high computation time.

TL;DR: In this article, the transient vibration response of a cracked rotor passing through its critical speed is analyzed, as an attempt for crack detection and monitoring, and effects of different factors such as crack depth, unbalance eccentricity with phase and acceleration influencing vibration are investigated.

TL;DR: In this paper, an energy method is applied to design configurations for the perfect elimination of the influence of ideal springs, acting on rotatable bodies, on arbitrary coupler points of four-bar linkages and on two-link open loop kinematic chains.

TL;DR: In this article, it was shown that the Cartesian stiffness matrix associated with a linear elastic coupling between two rigid bodies is, in general, asymmetric if the resulting forces and moments do not sum to zero.

TL;DR: In this article, the coupling between bending and torsion due to gears as well as the effect of axial torque on bending vibrations is taken into account to determine the coupled lateral and Torsional response due to torsional excitation.

TL;DR: In this article, a linear regression method to minimize the deviations of a real cut gear-tooth surface is investigated, based on the Gleason hypoid gear generator, a mathematical model of the tooth surface is proposed.

TL;DR: In this paper, an experimental investigation on the speed and torque loss components of the power loss of a rubber V-belt continuously variable transmission (CVT) as operating conditions (parameters) change is presented.

TL;DR: In this article, a new set of branch coordinates are introduced and used to define the time-varying configuration of a planar multibody system with open and closed kinematic chains.

TL;DR: In this article, the authors proposed an approach that enables one to localize and stabilize the bearing contact, and simplify the design of a face-gear free of undercutting and pointing.

TL;DR: In this article, the 3-RPR parallel manipulator is studied in the Clifford algebra of the projective plane, C + (P 2 ), which yields a manifold defining its set of reachable positions and orientations.

TL;DR: In this article, the stiffness mapping matrix for a planar compliant mechanism is analyzed using two different reference frames, one rigidly attached to the fixed body of the coupling and the other attached to a moving body.

TL;DR: In this article, it was shown that the dynamic equations of a parallel manipulator have a parallel structure and that this parallelism gives rise to a recursive formula for the inverse of the inertia matrix of the manipulator.

TL;DR: In this article, the screw system spanned by the wrenches associated with the actuated joints of the branches and also by the screws reciprocal to all the joints of degenerate branch configurations can be concluded to always have an order of six for redundant actuation of all main-arm joints.

TL;DR: In this article, a method of designing high-contact-ratio spur gears using quadratic parametric tooth profiles for the shorter addendums and no undercut was proposed.

TL;DR: A centro-based characterization of singularities in planar multi-DOF mechanisms with arbitrary kinematic structure has been presented in this paper, where the singularities have been classified into five types and their physical implications have been explained.

TL;DR: In this article, the composition principle of kinematic chains with multiple joints is discussed, and a factor of M.J. about kinematics chain with multiple-joints is defined, so that the structural analysis and synthesis of the K.C. with MJ. could be simplified.

TL;DR: In this paper, a novel approach, employing Pythagorean-hodograph (PH) curves to define transitional segments of the pitch curve, is described: the polynomial rectification and rational offset properties of these curves eliminate computational limitations to the accuracy of cam manufacture.

TL;DR: The mathematical model of multiple non-redundant rigid robot manipulators performing cooperative work on a single dynamical object of which the motion is constrained by a dynamical environment is presented.

TL;DR: In this paper, a new method for tooth contact analysis in mismatched hypoid gears is applied for the investigation of the influence of misalignments of the mating members on mesh performances.

TL;DR: In this paper, the concept of enveloping tangent planes dealing with gear geometry and normal deviations is applied to bevel gears and exact spherical involute is established by the procedure outlined in this paper.