PERCE's GRIPES: A robot grasp planner

This project deals with design and development of an advanced multi-fingered gripper designed by using Pro- E and ANSYS. In this research work are motivated by the requirement for grasping of the objects of arbitrary shape and size. The key issues consider here are: the gripper should be able to grasp the object of any shape, size, and weight (with a maximum limit); stability of the object held during the manipulations; should not dependent on the frictional forces between gripper and object; synchronization in fingers motion; and employment of the minimum number of the actuators to manipulate the grippers. Kinematic and dynamic analyses of the gripper are made to support this novel design. The gripper was successfully designed, Analyzed hence can find many applications, e.g., as a robot end effectors, prosthetic hands etc. The robotics, end effectors are a device at the end of a robotic arm, designed to the interact with the environment. Gripper was ending effectors or tool to grasp any physical thing that may be a human hand or any instruments. This type of gripper designed is an impactive type which uses jaws or claws to the physically grasp by direct impact upon the object. A pneumatic pressure was used to actuate the fingers of the gripper. In this project, a simple mechanism is developed for grasping irregular object shapes by using a four-fingered robotic gripper. To the achieve this goal we intend to the incorporate a simple linkage actuation mechanism. The gripper can perform the basic function of picking, holding and grasping of the irregularly shaped objects. The grippers are simple in construction, minimum complexity, and easy manufacturability. The focuses of this project are to achieve four-finger grasp of the irregularly shaped objects.

2008 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, 2008

Automatic grasp planning systems are very important for service robots, which compute what forces should be exerted onto the object and how those forces can be applied by robotic hands. In this paper, a highly integrated grasp planning system is introduced. Initial grasp is computed in the grasp simulator GraspIt! combining hand preshapes and automatically generated approach directions. With fixed relative position and orientation between the robotic hand and object as by the initial grasp, all the contact points between the fingers and the object are efficiently found. A search process tries to improve the grasp quality by moving the fingers to its neighbored joint positions, and uses the corresponding contact points to the joint position to evaluate the grasp quality, until local maximum grasp quality is reached. Optimal forces for the found grasp is computed as a linear inequalities matrix problem, which are exerted onto the object using torque based finger impedance control during execution. Experiments on Schunk Anthropomorphic Hand with 13 degrees of freedom show that, using the introduced grasp planning system, the object can be grasped solidly with shift errors of only some millimeters.

2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012), 2012

This paper introduces a novel grasp planning algorithm which can find feasible grasps within a few milliseconds. The object surface is decomposed into plenar regions, which will be decomposed into smaller ones until a discrete grasp can be determined. We have extended the grasp wrench space formulation for the grasp regions and use ray-shooting method to evaluate the force-closure property of the grasp. Experiments in simulation show the efficiency of our algorithm.

2012

This work proposes an algorithm for designing a simple End Effector configuration for a robotic arm which is able to grasp a given set of objects. The algorithm searches for a common 3-finger grasp over a set of objects. The search algorithm maps all possible grasps for each object which satisfy a quality criterion and takes into account an external wrench (force and torque) applied to the object. The mapped grasps are represented by feature vectors in a high-dimensional space. This feature vector describes the shape of the gripper. We then generate a database of all possible grasps for each object represented as points in the feature vector space. Then we use another search algorithm for intersecting all points over the entire sets and finding common points suitable for all objects. Each point (feature vector) is the grasp configuration for a group of objects, which implies for the end-effector design. The final step classifies the grasps found to subsets of the objects, according to the common points found, this with preference to find one grasp to all the objects. The algorithm will be useful for assembly line robots in reducing end-effector design time, end-effector manufacturing time and final product cost.

IEEE International Conference on …, 2003

Lecture Notes in Mechanical Engineering, 2020

This work presents grasp planning on everyday objects using vision. The hand considered is a one degree-of-freedom parallel jaw gripper of Mitsubishi Movemaster robot. Candidate grasping points are chosen on the object and a grasp matrix is computed for the grasp. The grasp matrix can be used to computationally determine a force-closure grasp feasibility. For selecting the candidate grasping points, image of the object is used. Three quality metrics based on different physical notions of quality of grasp are computed. The first quality measure tells how far a grasp is from violating the friction limits, the second gives the worst case performance of the force-closure for all external wrenches, and the third tells how well the object is enclosed from all directions. The main contribution of the paper is to compare grasps based on different quality measures and understand their physical interpretation.

Algorithmica, 2000

This paper addresses the problem of grasping and manipulating three-dimensional objects with a recon gurable gripper that consists of two parallel plates whose distance can be adjusted by a computer-controlled actuator. The bottom plate is a bare plane, and the top plate carries a rectangular grid of actuated pins that can translate in discrete increments under computer control. We propose to use this gripper to immobilize objects through frictionless contacts with three of the pins and the bottom plate, and to manipulate an object within a grasp by planning the sequence of pin con gurations that will bring this object to a desired position and orientation. A detailed analysis of the problem geometry in con guration space is used to devise simple and e cient algorithms for grasp and manipulation planning. The proposed approach has been implemented and preliminary simulation experiments are discussed.

Robotics and Autonomous Systems, 2011

This overview presents computational algorithms for generating 3D object grasps with autonomous multi-fingered robotic hands. Robotic grasping has been an active research subject for decades, and a great deal of effort has been spent on grasp synthesis algorithms. Existing papers focus on reviewing the mechanics of grasping and the finger-object contact interactions Bicchi and Kumar [12] or robot hand design and their control Al-Gallaf et al. (1993) [70]. Robot grasp synthesis algorithms have been reviewed in [71], but since then an important progress has been made toward applying learning techniques to the grasping problem. This overview focuses on analytical as well as empirical grasp synthesis approaches.

Mechanism and Machine Theory, 1998

Computation of the grasping force between the fingers and object is one of the main requirements for object manipulation. Traditionally the upper bound on the magnitudes of the grasping forces have been determined based on some local static constraints using optimization techniques. These methods usually do not incorporate the actual properties of the motion trajectories and external forces which can act on the grasped object. In addition, in most cases, various subproblems of the general grasping have been considered and a comprehensive method for modelling and analysis of such a system has not been addressed in the literature. This paper presents a general, efficient and elegant framework for computing the grasping forces in dynamics manipulation of objects. The presented framework is general and does not rely on any special relationships between the configuration of the end-effector and properties of the grasped object. The method takes into account the external task forces and the inertia force and then adaptively determines the required grasping forces as a function of the local contact friction properties. It utilizes the screw geometry, Lie algebra, inner product spaces and information regarding the grasp geometry and its motion trajectories. The method of the paper is also demonstrated through an example.

Abstract— In this article a robotic gripper with the ability of cylindrical object grasping is designed and fabricated. With the increasing use of robotic arms in industry, grasping and holding, as a part of industrial processes, are of great importance. Hence, proper design of grippers plays a key role in efficient performance of robotic arms. The main feature of this design is its reliability and efficiency while maintaining simplicity. This robotic gripper is designed for installing on a mobile robot with the task of holding and moving cylindrical object. One of the aspects of an efficient robotic gripper is its ability to satisfy the “Form-gripping” feature which is utilized for the presented design. Kinematic consideration is examined by Catia. Finally, control methods through Matlab and experimental test results are presented in this paper.