117 research outputs found
Causality : exploratory data analysis and knowledge discovery
No full textD.Phil. (Electrical and Electronic Engineering)Abstract: The phenomenon of cause and effect which rules the natural behaviour of the universe is simple in observation but complicated in interdependency. While all action and reaction states observed in time space are easier to work on, still the difficulty lies in the factor relations. Only knowing the facts/features without the time frame as they occurred/observed heightens the complexity of information retrieval. The relation of cause and effect is vital for knowing the past information which constructs the present state, although feature links remain debatable in this case. The study of Causality deals with these exploratory data analysis problems to inform all possible vital facts which can be extracted from the feature sets. Many researchers also consider the Causal Analysis as the golden standard in data mining and analysis. As is frequently the case, this causal analysis is represented by directed acyclic graphs for simplification of complexity. The directed edges with weighted values inform the flow of information from source/parent to the receiver/child nodes in the graph. The definition of the causal structure for inference analysis is insufficient for many reasons, and the works concluded in this field are inadequate. Most of the techniques proposed provide limited structural analysis, while many others are not able to validate the required criteria for causal analysis. The background study of all the proposed articles with definite contributions towards causality have been studied and are thoroughly analyzed in the literature review. All the methods proposed yet, use the bivariate model for causal analysis. In this scenario, the model, Linear Non-Gaussian Acyclic Model (LiNGAM) is the first to provide estimation for the most number of features. However, it is not completely effective in analyzing the causal models for datasets of mixed distribution types and also constructing a complete causal model from the estimated results is not possible. While using the fundamental structure of LiNGAM, the estimation process for causal detection is newly introduced by the method Altered-LiNGAM (ALiNGAM) in this work. ALiNGAM uses least square estimation on dseparable sets to find the probable causal directions in the observed feature set. The proposed..
Kinematic Analysis of Multi-Fingered, Anthropomorphic Robotic Hands
No full textThe ability of stable grasping and fine manipulation with the multi-fingered robot hand with required precision and dexterity is playing an increasingly important role in the applications like service robots, rehabilitation, humanoid robots, entertainment robots, industries etc.. A number of multi-fingered robotic hands have been developed by various researchers in the past. The distinct advantages of a multi-fingered robot hand having structural similarity with human hand motivate the need for an anthropomorphic robot hand. Such a hand provides a promising base for supplanting human hand in execution of tedious, complicated and dangerous tasks, especially in situations such as manufacturing, space, undersea etc. These can also be used in orthopaedic rehabilitation of humans for improving the quality of the life of people having orthopedically and neurological disabilities. The developments so far are mostly driven by the application requirements. There are a number of bottlenecks with industrial grippers as regards to the stability of grasping objects of irregular geometries or complex manipulation operations. A multi-fingered robot hand can be made to mimic the movements of a human hand. The present piece of research work attempts to conceptualize and design a multi-fingered, anthropomorphic robot hand by structurally imitating the human hand.
In the beginning, a brief idea about the history, types of robotic hands and application of multi-fingered hands in various fields are presented. A review of literature based on different aspects of the multi-fingered hand like structure, control, optimization, gasping etc. is made. Some of the important and more relevant literatures are elaborately discussed and a brief analysis is made on the outcomes and shortfalls with respect to multi-fingered hands. Based on the analysis of the review of literature, the research work aims at developing an improved anthropomorphic robot hand model in which apart from the four fingers and a thumb, the palm arch effect of human hand is also considered to increase its dexterity.
A robotic hand with five anthropomorphic fingers including the thumb and palm arch effect having 25 degrees-of-freedom in all is investigated in the present work. Each individual finger is considered as an open loop kinematic chain and each finger segment is considered as a link of the manipulator. The wrist of the hand is considered as a fixed point.
The kinematic analyses of the model for both forward kinematics and inverse kinematic are carried out. The trajectories of the tip positions of the thumb and the fingers with respect to local coordinate system are determined and plotted. This gives the extreme position of the fingertips which is obtained from the forward kinematic solution with the help of MATLAB. Similarly, varying all the joint
iv
angles of the thumb and fingers in their respective ranges, the reachable workspace of the hand model is obtained. Adaptive Neuro-Fuzzy Inference System (ANFIS) is used for solving the inverse kinematic problem of the fingers.
Since the multi-fingered hand grasps the object mainly through its fingertips and the manipulation of the object is facilitated by the fingers due to their dexterity, the grasp is considered to be force-closure grasp. The grasping theory and different types of contacts between the fingertip and object are presented and the conditions for stable and equilibrium grasp are elaborately discussed. The proposed hand model is simulated to grasp five different shaped objects with equal base dimension and height. The forces applied on the fingertip during grasping are calculated. The hand model is also analysed using ANSYS to evaluate the stresses being developed at various points in the thumb and fingers. This analysis was made for the hand considering two different hand materials i.e. aluminium alloy and structural steel.
The solution obtained from the forward kinematic analysis of the hand determines the maximum size for differently shaped objects while the solution to the inverse kinematic problem indicates the configurations of the thumb and the fingers inside the workspace of the hand. The solutions are predicted in which all joint angles are within their respective ranges.
The results of the stress analysis of the hand model show that the structure of the fingers and the hand as a whole is capable of handling the selected objects.
The robot hand under investigation can be realized and can be a very useful tool for many critical areas such as fine manipulation of objects, combating orthopaedic or neurological impediments, service robotics, entertainment robotics etc.
The dissertation concludes with a summary of the contribution and the scope of further work
Finite Element Based Vibration Analysis of a Nonprismatic Timoshenko Beam with Transverse Open Crack
No full textAbstractThe present day structures and machineries are designed based on optimizing of multi-objectives such as maximum strength, maximum life, minimum weight and minimum cost. Due to this they are flexible and allow having a very high level of stresses. This leads to development of cracks in their elements. Many engineering structures may have structural defects such as cracks due to long-term service. So it is very much essential to know the property of structures and its response in various cases. The present article deals with finite element based vibration analysis of a nonprismatic cracked beam. The beam is modeled using the Timoshenko beam theory. The governing equation of motion is derived by the Hamilton's principle. In order to solve the governing equation two noded beam element with two degrees of freedom (DOF) per node is considered. In this work the effect of structural damping is also incorporated in the finite element model. The dynamic analysis is carried out by using state space model in time domain
Finite Element Based Modeling of a Piezolaminated Tapered Beam for Voltage Generation
No full textAbstractThe present article deals with finite element (FE) based modeling of a nonprismatic piezolaminated cantilever beam for voltage generation. The beam is modeled using the Euler-Bernoulli beam formulation. The governing equation of motion is derived by using the Hamilton's principle. In order to solve the governing equation two noded beam element with two degrees of freedom (DOF) per node is considered. In this work the effect of structural damping is incorporated in the finite element model. The effects of taper (both in width and height direction) on output voltage are discussed as well
DESIGN AND ANALYSIS OF MULTI- FINGERED ROBOTIC GRIPPER
No full textThe aim of the project is to design and analyze multi-fingered robotic grippers which shall be used for the stable grasping of an object. The design and modeling shall be carried out using CAD software and the analysis of the mechanical properties of the respective robotic system shall be done by using suitable FEA software. A detailed analysis and comparison is made on three fingered and four fingered robotic grippers by the use of results provided by the FEA tool and then a thorough conclusion is formed at the end
Analysis of Inverse Kinamtics of an Anthropomorphic Robotic hand
No full textIn this paper, a new method for solving the inverse kinematics of the fingers of an anthropomorphic hand is proposed. Solution of inverse kinematic equations is a complex problem, the complexity comes from the nonlinearity of joint space and Cartesian space mapping and having multiple solutions.This is a typical problem in robotics that needs to be solved to control the fingers of an anthropomorphic robotic hand to perform tasks it is designated to do. With more complex structures operating in a 3-dimensional space deducing a mathematical soluation for the inverse kinematics may prove challenging. In this paper, using the ability of ANFIS (Adaptive Neuro-Fuzzy Inference System) to learn from training data, it is possible to create ANFIS network, an implementation of a representative fuzzy inference system using ANFIS structure, with limited mathematical representation of the system. The main advantages of this method with respect to the other methods are implementation is easy, very fast and shorter computation time and better response with acceptable error
- …
