Nahian Rahman

A novel bio-inspired modular gripper for in-hand manipulation

In the automation industry, in-hand manipulation is a frequently required task which needs a significant dexterity of grippers. Operations such as object twisting, re-grasp and repositioning with correct posture are the major challenges driving the gripper design and which determine its complexity. This paper proposes a new bio-inspired modular gripper which is capable to provide an object with motions of rotation about two independent axes. The proposed gripper is a modular device made of four identical fingers each one having two DOFs. Moreover, a proper mechanism was conceived to move two fingers out of four so as to ensure the grasping. In this research, the feasibility of the idea is proved by means of simulations in a multibody environment.

Kinematic analysis and synthesis of a novel gripper for dexterous applications

This paper demonstrates kinematic analysis and synthesis of a novel, modular, reconfigurable gripper, which is capable to manipulate plurality of object. The gripper consists of four identical modular fingers, dexterous among all axes. Each modular finger of the gripper is conceived to the aim of satisfying efficient grasping, manipulation and also object release with accordance of desired posture. The proposed gripper has 16 DOFs, which can be reduced by decreasing the number of fingers depending on its target uses. In this paper, the in-hand manipulation capability is explained from kinematic perspective and some analysis carried through to synthesize the gripper for user specific applications.

Dynamic Modelling and Analysis of an Articulated Robotic Leg

In robotics, both the analytical and numerical studies play a vital role to predict the dynamic behaviours of robotic systems. Nevertheless, dynamic modelling is essential to predict the system behaiours. In this paper, both the analytical and numerical approaches are worked out for a leg of a hydraulic quadruped robot. The research aims at the identification of system parameters like inertial and geometrical magnitudes of a complex assembled leg at various cases. Due to the articulated mechanism, the model owns a significant mathematical complexity which should be possibly reduced through a combined use of analytical and multibody tools as a preliminary step to experimental identification. Both simulations and experiments results have been carried out for the goal.Copyright

A dexterous gripper for in-hand manipulation

During the last few decades, robotic grippers are developed by research community to solve grasping complexities of several objects as their primary objective. Due to the increasing demands of industries, many issues are rising and remain unsolved such as in-hand manipulation, placing object with appropriate posture. Operations like twisting, altering orientation of object, in a hand, requires significant dexterity of the gripper that must be achieved from a compact mechanical design at the first place. In this paper, a newly designed gripper is proposed whose primary goal is to solve in-hand manipulation. The gripper is derived from four identical finger modules; each module has four DOFs, consists of a five bar linkage to grasp and additional two DOFs mechanism similar to ball spline is conceived to manipulate object. Hence the easily constructible gripper is capable to grasp and manipulate plurality of object. As a preliminary inspection, an optimized platform that represents the central concept of the proposed gripper is developed, to the aim of evaluating kinematic feasibilities of manipulation of different objects.

Kinematic Analysis, Prototypation and Control of a Novel Gripper for Dexterous Applications

Speed and flexibility are the primary concerns to whom a well designed industrial gripper should target. The first one leads to unquestionable pros in terms of production, while the second one to the ability of grasping and manipulating several payloads. However, these qualities are opposed to each other in terms of design requirements: speed requires a structure built of rigid bodies, flexibility would have to be favoured by the use of soft materials. As a common target, the human hand represents the most interesting inspiration source in this field, due to its natural dexterity and ability to perform in-hand manipulations. Thus, many bio-inspired or bio-mimicked grippers have been developed in the last decades with the final aim of replicating the terrific capabilities offered by the human hand. In such panorama, this paper presents the kinematic synthesis of a novel, modular, reconfigurable gripper, which is capable to manipulate a plurality of objects, being dexterous at the same time. Instead of using soft materials to achieve in-hand manipulation, the authors focused to use mechanisms to address the problem. The concept of manipulation is firstly evaluated in a multibody software environment, then a physical prototype was developed, and the necessary control laws were derived. Several experiments were conducted to test the effectiveness of the proposed structure. Results in terms of accuracy and repeatability are shown, and also the ability to address the three major tasks of grasp, in-hand manipulation and release with appropriate posture have been demonstrated.

Manipulation & workspace analysis of Dexclar: A newly formed DEXterous gripper

This paper demonstrates manipulation, workspace and dimensional synthesis process of a novel gripper named Dexclar (DEXterous reConfigurable moduLAR), which is capable to manipulate plurality of object. The aim to develop such gripper is to address some current industrial issues particularly the rising in-hand manipulation problem. Operations like twisting, flipping, altering orientation of an object, in a hand, require both the dexterous and adaptable properties of the gripper. To be adaptable or flexible to numerous objects while grasping or manipulating, the usual practice is to use soft material in the gripper design, which opposes the speed and dexterity of the overall operations. To solve that, Dexclar is proposed in this paper, which is supposed to build with rigid material with accordance to meet both the dexterity and manipulation problem. The 16 DOFs Dexclar is consists of four identical modular fingers, dexterous among all axes. Each modular finger is conceived to the aim of satisfying efficient grasping, manipulation and also object release with accordance to desired posture. In this paper, the in-hand manipulation, grasping and release capabilities are explained from kinematic perspective and some analysis carried through to synthesize the gripper for user specific applications.

Origami Carton Folding Analysis Using Flexible Panels

This paper demonstrates a virtual prototyping of origami carton folding process using flexible panels instead of using rigid panels. The aims of this work are, to study of contact forces between flexible panels and fingers and further also to explore different non-rigid materials to be considered as a panel-body in future for different synchronous carton folding applications. Similar to previous research, in this paper, the D-RAPS multi-finger robot has been used in simulation and the mechanism of the robot fingers are explained. That work also permits to investigate the torque between two panels.

KARL: A new bio-inspired modular limb for robotic applications

The modular and self-reconfigurable mechanisms are arising the interest of the robotics research community for their peculiarities of flexibility and cost effectiveness. In this scenario, this work presents a newly conceived device suitable for being used as a limb, as well as a planar two degrees of freedom manipulator, for robotic applications. The concept design here exposed merges the features of both parallel and serial kinematic mechanisms to obtain a limb whose primary characteristic is that of being independent from the frame to whom it is connected. In fact the actuation is realized by means of two linear motors directly arranged on the body and connected to the chassis through different closed kinematic chains. The manuscript introduces the formal aspects of this novel limb facing position, differential kinematics, expected performances and experimental results obtained thanks to a specifically built prototype.

A novel parallely actuated bio-inspired modular limb

An increasing interest towards functionally independent and self-reconfigurable robots featured the research direction in the recent past. Such attention is well explained by the characteristics of flexibility and cost-effectiveness which distinguish these modular machines. This scenario framed the birth of many different devices characterized by simplicity of use and versatility. The present manuscript follows these trends by presenting a newly conceived device suitable for being used as a limb, as well as a planar two degrees of freedom manipulator. The features of both parallel and serial kinematic mechanisms have been exploited to the aim of obtaining a device as much as possible independent from the frame to whom it is connected. Formal aspects about position and velocity kinematics are addressed and a specifically built prototype is then used for experimental tests on the new limb.