Adhesion State Estimation for Electrostatic Gripper Based on Online Capacitance Measure

Electroadhesion is a suitable technology for developing grippers for applications where fragile, compliant or variable shape objects need to be grabbed and where a retention action is typically preferred to a compression force. This article presents a self-sensing technique for electroadhesive devices (EAD) based on the capacitance measure. Specifically, we demonstrate that measuring the variation of the capacitance between electrodes of an EAD during the adhesion can provide useful information to automatically detect the successful grip of an object and the possible loss of adhesion during manipulation. To this aim, a dedicated electronic circuit is developed that is able to measure capacitance variations while the high voltage required for the adhesion is activated. A test bench characterization is presented to evaluate the self-sensing of capacitance during different states: (1) the EAD is far away from the object to be grasped; (2) the EAD is in contact with the object, but the voltage is not active (i.e., no adhesion); and (3) the EAD is activated and attached to the object. Correlation between the applied voltage, object material and shape and capacitance is made. The self-sensing EAD is then demonstrated in a closed-loop robotic application that employs a robot manipulator arm to pick and place objects of different kinds

Conceptual design of a gripper for a first-aid robot

First aid is the tentative care for anyone who is injured or ill before definitive medical care arrives. Advancements in technology offer robots the potential to be used extensively in first aid to replace human workers. Currently, many elderly people live alone and absence of care can increase risks of illness- or injury-induced unconsciousness. Due to this, it would be useful to investigate if robots could be employed to perform first-aid care. However, their application in aiding humans in such circumstances is still relatively rare due to complexities concerning safety, communication and ability to interact with humans. This thesis is part of a project to design a first-aid robot to manipulate an unconscious human from any position to the recovery position. The only direct contact with human is through gripper of the robot. An attempt to develop a conceptual design of cost-effective grippers has been undertaken. This will enable a robot to perform the handling and manipulation of human segments to achieve the recovery position. For the purpose of robotic application, a research into the feasibility of human body manipulation is being conducted. Initial stage of research is to identify the limit of physical robot-human interaction; the biomechanical characteristics of human body that decide these limits and essential gripper specifications required to theoretically carry out robot-human interactions to those limits. The research is focused on the geometric properties of various human body parts, defined as body segments, and the minimum gripper specification needed to manipulate these segments. A novel systematic design approach has been applied to the gripper by utilizing a design tool known as the Theory of Inventive Problem Solving (TRIZ). Results ii obtained from this study have substantiated design work to derive an enhanced design solution, which will enable the gripper to perform delicate tasks. The gripper‟s main priorities have been identified and concluded that fundamental issues are: safely engaging human segments and preventing pain exceeding the recommended pain threshold. This work could form the basis of developing and integrating the First Aid Robotic System (FAROS) and pave a way for further developments and innovations

Design of Robot Gripper Mechanism for ROBOCON Robot Competition

The project is conducted by assumptions that are prototype built will consist of only lifter and gripper and cost for project research and prototype are neglected. Since there is no robot base and no movement of robot, the workpieces are feed into gripper jaw opening by external action. The outcome is development of an aluminum prototype model of a robot gripper

Modelling and Simulation of a Manipulator with Stable Viscoelastic Grasping Incorporating Friction

Design, dynamics and control of a humanoid robotic hand based on anthropological dimensions, with joint friction, is modelled, simulated and analysed in this paper by using computer aided design and multibody dynamic simulation. Combined joint friction model is incorporated in the joints. Experimental values of coefficient of friction of grease lubricated sliding contacts representative of manipulator joints are presented. Human fingers deform to the shape of the grasped object (enveloping grasp) at the area of interaction. A mass-spring-damper model of the grasp is developed. The interaction of the viscoelastic gripper of the arm with objects is analysed by using Bond Graph modelling method. Simulations were conducted for several material parameters. These results of the simulation are then used to develop a prototype of the proposed gripper. Bond graph model is experimentally validated by using the prototype. The gripper is used to successfully transport soft and fragile objects. This paper provides information on optimisation of friction and its inclusion in both dynamic modelling and simulation to enhance mechanical efficiency

Design of a Smart Gripper for Industrial Applications

The gripper is the most important part from an industrial robot. This one interacts with the environment that surrounds the robot. Nowadays, the industrial robot grippers have to be tuned and custom made for each application by engineers, searching to get the desired repeatability and behaviour. This thesis discusses the design of a smart and flexible gripper for industrial activities. This means that the gripper has to be able to sense the environment that surrounds it. For this will be need to choose different sensors for improving its flexibility and function ability. Furthermore, a power tool finger will be added for make the gripper able to use power tools. With all of these the aim is to choose a design that can be able to be more independent than the other grippers that already exist in the industry. Also tries to keep it easy and the low costs. This thesis also will 3D print a prototype of the results from the design discussions. This prototype would not be functional, it will be for represent the results

Effects of residual charge on the performance of electro-adhesive grippers

Electro-adhesion is the new technology for constructing gripping solutions that can be used for automation of pick and place of a variety of materials. Since the technology works on the principle of parallel plate capacitors, there is an inherent ability to store charge when high voltage is applied. This causes an increased release time of the substrate when the voltage is switched off. This paper addresses the issue of residual charge and suggests ways to overcome the same, so that the performance of the gripper can be improved in a cycle of pick and release. Also a new universal equation has been devised, that can be used to calculate the performance of any gripping solution. This equation has been used to define a desired outcome (K) that has been evaluated for different configurations of the suggested electro-adhesive gripper