Kinematic Model In Order Research Articles

Stretchable-thickness model for dynamic responses of graphene origami reinforced badminton sport plate

In this article, we organize a stretchable-thickness model to present a frequency analysis for a composite plate applicable in badminton court which is reinforced with origami graphene. A higher order kinematic model is extended in this work including three bending, shear, and stretching functions, where the stretching functions is responsible for satisfying the out of plane shear strains and stresses at top/bottom surfaces of the badminton equipment. The sport or composites plate is manufactured from a copper matrix reinforced with graphene origami where the effective material properties are calculated based on micromechanical models as a function of volume fraction and folding degree of graphene origami, material properties of matrix and reinforcement and temperature. The numerical results are presented with changes of volume fraction, folding degree of reinforcement, and thermal loading along the thickness direction. The main novelty of this work is accounting thickness stretching deformation for the analysis of a graphene origami reinforced plate and investigating the responses of graphene origami as a new reinforcement. A verification investigation is presented for approve of the methodology, and solution procedure. An investigation on the order of deformation is presented for various thickness ratio of the badminton sport plate.

Robust Arbitrary-Time Path-Tracking Control Using Reduced Order Kinematic Model for Unmanned Ground Vehicles

Robust Arbitrary-Time Path-Tracking Control Using Reduced Order Kinematic Model for Unmanned Ground Vehicles

An effort for resolving redundancy of a multi-finger robotic hand in straight-line motions

Multi-finger robotic hands are the main robotic invention for providing assistive movement therapy in hand rehabilitation. In this paper, the concept of task priority is adopted in order to solve the redundancy resolution of a robotic hand. The redundancy parameter has been used to design the inverse kinematic model in order to determine the joint angles when the finger moves to perform the initial subtask of tracing the desired trajectory while considering the secondary subtask of increasing the instantaneous manipulability. Five different human subjects performed the experimentation where the index finger and thumb are allowed to follow the three desired motion trajectories. Markers are placed on the finger joints in order to track the motion and obtain the finger joint angles. Further, the experimental joint angles are compared with those obtained from inverse kinematics. The index finger and thumb behaviour is analysed based on the redundancy resolution scheme. It has been observed that the optimized root-mean-square error remains insignificant of the different subjects performing the motion and the type of motion trajectories adopted for the index finger as well as the thumb. Thereafter, the proposed scheme is applied to a four-finger tendon-actuated robotic hand and it has been observed that the scheme can be applied to solve the redundancies of any robotic hand.

Pose Observation for Second Order Pose Kinematics

This paper proposes an equivariant observer for second order pose estimation of a rigid body. The observer exploits the second order kinematic model and its symmetry group. The observer uses conventional sensors and simple computations that allow it to be run on resource-constrained devices. The observer design is based on the lifted kinematics and we prove its asymptotic convergence property. The performance of the observer is demonstrated in simulation.

Leader-Follower Control Strategy with Rigid Body Behavior

Abstract This work presents a control strategy for a leader-follower formation distance-based model of two single order kinematic model of robots. It uses feedback linearization techniques to derive the control action on the follower robot to maintain a desired distance and orientation with respect to the leader robot. Besides, it is shown that a suitable selection of the desired parameters make the formation behave as a rigid body. The control strategy is applied in a laboratory environment with two omnidirectional robots to show its performance.

Kinematic Analysis of Planar Parallel Mechanism

The paper deals with kinematic model of parallel mechanism equipped with elastic members. The main aim is to determine the workspace of particular point of the mechanism in order to designing of whole mechanism for the future. Whole mechanisms should consist of several same segments which creates concept of serial mechanism. Since there is investigated parallel mechanism, at first has to be solved inverse kinematic model in order to obtain generalized variables, which are necessary for direct kinematic model. In the paper Jacobian matrix is derived for investigated mechanism. Then the algorithm for inverse kinematic model is described. The inverse kinematic model uses damped least squares method which appears as suitable method for our purposes. The results of inverse kinematic solution is consequently used for direct kinematic model, which is described by homogeneous transformation matrices. The planar parallel mechanism is simulated in software Matlab and the results are expressed in the graphs as well as our approach is discussed in the conclusion.

Kinematic analysis and experimental investigation on vibratory finishing

Vibratory finishing has been widely used for surface polishing, burnishing, edge finishing, texturing, and cleaning with a wide variety of different media. Medium properties and their motions dominate material removal efficiency and surface treatment quality in the vibratory finishing process. In this study, medium kinematic model and movement simulation of vibratory finishing were developed. Medium motion simulation was verified through a digit video recorded by a high-speed camera. It was found that medium kinematic path line is a circular-feeding helical motion, which is determined by the angular velocity ratio between the rolling and feeding, the rotation direction, and vibratory finishing machine configuration. Material removal intensity model was further established based on the kinematic model in order to better understand the vibratory finishing process. The optimal fixing location and orientation of workpiece were obtained through the analysis of the kinematic model. Finishing experiments were further carried out for the Ti6Al4V test pieces which were fixed onto the wall of a vibratory bowl. The surface roughness, Ra values (with initial surface roughness of 1.50 μm), approached to 0.13 μm after processing time of 2.5 h and 0.10 μm after processing time of 6.0 h. Surface quality of finished test pieces has been significantly improved as compared with the existing method (i.e., loosed workpiece in the vibratory bowl), whereby the surface roughness, Ra values (with initial surface roughness of 1.50 μm), tapered off (saturated) to about 0.52 μm with the increase of processing time.

Control of 2D Minimally Persistent Formations with the Fault Tolerance of Three Co-Leaders in Cycle

This paper mainly addresses a novel control law with rigidity matrix based on three co-leaders minimally persistent formations in the plane. This control law particularly considers the fault tolerance of the leaders, and in this way, the three co-leaders model is better than leader-first follower model, leader-remote follower model, etc. in persistent formation. Firstly, the first order kinematic model is adopted for every agent. Then the fundamental moving principal of the leaders and the followers are described in detail. On the basis of these principals, the control law with the rigidity matrix for the whole formation is proposed. Moreover, the stability analysis is also supplied. Finally, simulations show that the proposed controllers ensure the group formation stabilized to maintain the rigid shape, while the distances between the agents remain unchanged.

Chaotic advection in a steady, three-dimensional, Ekman-driven eddy

AbstractWe investigate and quantify stirring due to chaotic advection within a steady, three-dimensional, Ekman-driven, rotating cylinder flow. The flow field has vertical overturning and horizontal swirling motion, and is an idealization of motion observed in some ocean eddies. The flow is characterized by strong background rotation, and we explore variations in Ekman and Rossby numbers, $E$ and ${R}_{o} $, over ranges appropriate for the ocean mesoscale and submesoscale. A high-resolution spectral element model is used in conjunction with linear analytical theory, weakly nonlinear resonance analysis and a kinematic model in order to map out the barriers, manifolds, resonance layers and other objects that provide a template for chaotic stirring. As expected, chaos arises when a radially symmetric background state is perturbed by a symmetry-breaking disturbance. In the background state, each trajectory lives on a torus and some of the latter survive the perturbation and act as barriers to chaotic transport, a result consistent with an extension of the KAM theorem for three-dimensional, volume-preserving flow. For shallow eddies, where $E$ is $O(1)$, the flow is dominated by thin resonant layers sandwiched between KAM-type barriers, and the stirring rate is weak. On the other hand, eddies with moderately small $E$ experience thicker resonant layers, wider-spread chaos and much more rapid stirring. This trend reverses for sufficiently small $E$, corresponding to deep eddies, where the vertical rigidity imposed by strong rotation limits the stirring. The bulk stirring rate, estimated from a passive tracer release, confirms the non-monotonic variation in stirring rate with $E$. This result is shown to be consistent with linear Ekman layer theory in conjunction with a resonant width calculation and the Taylor–Proudman theorem. The theory is able to roughly predict the value of $E$ at which stirring is maximum. For large disturbances, the stirring rate becomes monotonic over the range of Ekman numbers explored. We also explore variation in the eddy aspect ratio.

Automatic finite element formulation and assembly of hyperelastic higher order structural models

The formulation of higher order structural models and their discretization using the finite element method is difficult owing to their complexity, especially in the presence of nonlinearities. In this work a new algorithm for automating the formulation and assembly of hyperelastic higher-order structural finite elements is developed. A hierarchic series of kinematic models is proposed for modeling structures with special geometries and the algorithm is formulated to automate the study of this class of higher order structural models. The algorithm developed in this work sidesteps the need for an explicit derivation of the governing equations for the individual kinematic modes. Using a novel procedure involving a nodal degree-of-freedom based automatic assembly algorithm, automatic differentiation and higher dimensional quadrature, the relevant finite element matrices are directly computed from the variational statement of elasticity and the higher order kinematic model. Another significant feature of the proposed algorithm is that natural boundary conditions are implicitly handled for arbitrary higher order kinematic models. The validity algorithm is illustrated with examples involving linear elasticity and hyperelasticity.

A Kinematic Model for Volumetric Error Estimation of a Special Purpose CNC Machine

This research reports on error identification and compensation of a special purpose CNC machine. The kinematic model of the machine was developed using rigid body kinematics and small angle approximation of the axes of the machine through homogenous transform matrices, and the equations describing the volumetric errors. The machine was calibrated to measure the axes errors, which were used in the kinematic model in order to determine compensation values. The model was evaluated by means of direct measurements of axis movements using a laser interferometer, as well as in cutting tests, where a large number of holes were drilled in plates and measured with a CMM. The results showed that the developed model achieved an average error reduction of 40%, for the X and Y axes.

Calibration of an articulated CMM using stochastic approximations

A coordinate measuring machine (CMM) is meant to digitise the spatial locations of points and feed the resulting measurements to a CAD system for storing and processing. For reliable utilisation of a CMM, a calibration procedure is often undertaken to eliminate the inaccuracies which result from manufacturing, assembly and installation errors. In this paper, an Immersion digitizer coordinate measuring machine has been calibrated using an accurately manufactured master cuboid fixture. This CMM has been designed as an articulated manipulator to enhance its dexterity and versatility. As such, the calibration problem is tackled with the aid of a kinematic model similar to those employed for the analysis of serial robots. In addition, a stochastic-based optimisation technique is used to identify the parameters of the kinematic model in order for the accurate performance to be achieved. The experimental results demonstrate the effectiveness of this method, whereby the measuring accuracy has been improved considerably.

Human Gait Feature Extraction Including a Kinematic Analysis toward Robotic Power Assistance

The present work proposes a method for human gait and kinematic analysis. Gait analysis consists of the determination of hip, knee and ankle positions through video analysis. Gait kinematic for the thigh and knee is then generated from this data. Evaluations of the gait analysis method indicate an acceptable performance of 86.66% for hip and knee position estimation, and comparable findings with other reported works for gait kinematic. A coordinate systems assignment is performed according to the DH algorithm and a direct kinematic model of the legs is obtained. The legs' angles obtained from the video analysis are applied to the kinematic model in order to revise the application of this model to robotic legs in a power assisted system.

A modified kinematic model for particle flow in moving beds

Granular materials are utilized in a wide variety of industrial applications. The complex hydrodynamics of granular flow is still not fully understood. The flow characteristics of solid particles in a two-dimensional moving bed were studied experimentally and theoretically. The effects of mass velocity, properties of particles and the shape of moving bed on flow pattern were examined. The experiments show that the mass velocity of solid particles and the placement of baffles in stagnant zones have no effect on flow pattern. The shape, size and repose angle of particles affect the flow pattern greatly. The particles have more liquidity and the mixture between particles is easier with the increasing of sphericity degree of particles and the decreasing of particle size. The shape of flowing zone becomes more sharp-angled with the increasing of the repose angle, and the stagnant zone becomes larger. The kinematic model was used to simulate the particle flow. For center discharge the simulation results are in agreement with experiment data very well, while for eccentric discharge the simulation couldn't show the effects of side walls on particle flow. An analytic solution of kinematic model was obtained by Lie transformation group. It shows that the velocity of particle flow is the maximum when x equals 0. The method of translational coordinate was used to modify the traditional kinematic model in order to make sure the x value of each point on the maximum particles velocity distribution lines is zero. The modified kinematic model could simulate the eccentric discharge well, and the field of kinematic model applications was expanded.

Kinematic Model for Determination of Human Arm Reachable Workspace

In physiotherapy, a standard method to determine the movability and functionality of the human arm is to measure the ranges of motion in joints in sagittal, horizontal and frontal plane. It is clear, however, that these angles can hardly interpret the characteristics of the arm. The main idea in the article is to combine these angles with an adequate kinematic model in order to compute and graphically represent the reachable workspace of the arm, which then serves as an advanced criterion for a more objective evaluation. In this article, we report an improved kinematic model of the human arm which is appropriate for computing and visualizing the human arm reachable workspace. Optical measurements were performed to define the structure and parameters of the model and to develop the mathematical relations between the joint angles. The kinematic model was implemented in a computer programme which is now being introduced in practice and can be used in rehabilitation, ergonomics and sports.

Geomorphic evidence and kinematic model for quaternary transfer faulting of the Pakuashan anticline, Central Taiwan

The Pakuashan–Tatushan anticline and the related Changhua thrust are characterized by a regional curvature of the deformation front, which deviates from the general trend of the thrust system in the Western Foothills of Taiwan. A Quaternary transfer fault zone, which accommodates the motion of connected thrust sheets over an oblique feature of the preexisting margin basement, is proposed to explain this regional phenomenon. There are distinct morphological features in the Pakuashan ridge related to the transfer faulting. The stream valley orientations responding to the regional slope change and left-laterally offset valleys concur to support the existence of the tear faults. These observations lead us to propose a 2-D kinematic model in order to illustrate the geometry of the Pakuashan ridge adjusted by the tear faulting. Based on this kinematic model, we infer that the Changhua thrust system moves over an oblique ramp which bounds the Peikang Basement High. The oblique ramp is composed of three segments corresponding to the northern, central and southern Pakuashan. The gentle northern and southern ramps are connected by the steep central ramp. This ramp model can illustrate the kinematics of the Pakuashan transfer fault zone and has the potential to predict the local deformation (extension and compression) with respect to the geometry of the intersection of oblique ramps. The Pakuashan–Tatushan anticline and the related Changhua thrust system is one of typical examples of thrust sheet deformation associated with oblique ramps.

Application of an automatic method for determining normal fault geometries

An automatic method is used to determine the geometries of normal faults on depth-converted seismic reflection profiles from the Gulf of Mexico and from the North Sea. The general method has previously been tested on synthetic and sand-box data and assumes that the hanging wall deforms within the plane of section by a combination of arbitrarily inclined, bulk simple-shear and differential compaction. The range of possible solutions is systematically investigated using inverse modelling. We assume that the fault surface does not significantly change shape during deformation. However, inversion of flexural forward models shows that when the fault surface does change shape, the misfit function at an automatically determined solution is unacceptably large and featureless. Consequently, spurious solutions, obtained when the principal assumptions break down, can be identified. The approximations used in modelling the effects of differential compaction are justified by a range of appropriate synthetic models. We reiterate that the inversion procedure is dependent upon careful identification of: (a) two or more deformed horizons within the hanging wall; and (b) the regional levels of deformed horizons before deformation. The numerical stability of the scheme is demonstrated by inverting synthetic data to which random and systematic noise have been added. The solutions we have obtained are good and indicate that the method works regardless of the scale and shape of the faults. Throughout, we emphasize the importance of combining inverse theory with a simple kinematic model in order to investigate the solution space and the resolution of the model parameters obtained.