Three methods for formulating the dynamic model of parallel manipulators are compared in terms of their computational efficiency. The first two have been previously presented in the literature while the last one is introduced in this paper. Analysis of these numerical formulations provides a guideline for computational cost reduction for optimal design of this type of manipulator and for real-time embedded control.
In this work we analyze the main differences in muscle force production between the three different and widely used Hill-type muscle models (Soest and Bobbert, Silva-Kaplan and Thelen). As this work shows, there are slight differences between the obtained muscle efforts that arise from the assumptions made on each model. The computational effort or the control of the parameters involved in the experiments may determine the use of any of these descriptions of muscle tissue.
We propose two Interval Analysis based methods to characterize novel robots. Interval analysis theory allows us to consider intervals instead of values, making it possible to use computer algorithms, without the drawback of rounding errors. The first proposed method can isolate chosen interest points and is applied to the characteristic cusp and node points of 3R orthogonal manipulators. The second method encloses the robot available postures, giving complementary information on the novel robot.
The paper introduces a comprehensive symbolic matrix representation for characterizing the topology of a metamorphic mechanism using general information concerning links and joints. Operations on the matrices of the adjacent configuration mechanisms are defined to construct an origin matrix and joint variation matrices. The representation of the configurations and evolution of metamorphic Mechanisms provides a foundation for the analysis and synthesis of novel metamorphic mechanisms.
This paper presents the output decoupling property of flexure-based mechanisms. The model shows that mechanisms are output decoupled when they are symmetry about two perpendicular axes or when they are composed of either three or an even number of identical limbs distributed evenly around the center. The results obtained from the proposed model and FEA are almost same, which validates the model. It provides a reference point for further studies on the design and optimization of mechanisms.
The offset panel technique (OPT) is a method which accommodates for the use of thick materials in origami models and preserves both the range of motion and the kinematics. This work explores new possibilities for origami-based product applications presented by the OPT. Examples are included to illustrate some of the capabilities of the OPT, including the use of various materials in a design and manipulation of panel geometry resulting in increased stiffness and strength in the design.
Our work mainly focuses on the dynamic modeling of a piezoelectric actuator (PA) in the impact drive mechanism in the case of the in-pipe inspection application. The novel model we have developed is able to capture the inertia of the PA and the feature of this model is its computational efficiency with reasonable accuracy. This study has concluded that the inertia of the PA in such a robot can significantly affect the accuracy of the entire model of IDM.
the effect of machining parameters and recrystallization on surface quality of Al5083 has been investigated. In order to achieve minimum surface roughness of aluminum 5083 samples, statistical test design method of "full factorial" was used. In order to achieve the phenomenon of recrystallization, aluminum 5083 samples were set under 50 % cold rolling mechanical operations. roughness, tensile, and microstructure tests indicated the reduction of surface roughness in crystallized sample.
The subject of this work is modeling of single-bodied wheeled mobile robots. In the past, it was shown that the kinematics of each such robot can be modeled by one out of only five different generic models. However, the precise conditions under which a model is the proper description of the kinematic capabilities of a robot were not clear. These shortcomings are eliminated in this work, leading to a simple procedure for model selection and a classification of singularities.
The "double-banana" problem is a counter-example of Laman's rigidity condition formula for which existing standard Degree of Freedom counting formulas fail. The novelty of the approach for rigidity detection presented in this paper consists in regarding the structure not as a set of joint-connected bodies but as a set of interconnected loops. By tracking isolated DOFs such as those arising between pairs of spherical joints, rigidity/mobility subspaces can be identified successfully.
This paper presents the design and testing of a new large-range compliant microgripper. The gripper arms not only provide large gripping range but deliver approximately rectilinear movement as the displacement in nonworking direction is extremely small. The large gripping range is enabled by a dual-stage flexure amplifier to magnify the stroke of piezoelectric actuator. Finite-element analysis simulation study has been conducted. A prototype of the gripper is developed for experimental testing.