Screw-Nut Robotized Assembling (original) (raw)
Design and Development of a Lead Screw Gripper For Robotic Application
Mechatronics and Applications: An International Journal (MECHATROJ)
This paper gives details on the electromechanical design concept and prototype development of a lead screw linear actuated, parallel robotic gripper. Robotic applications are known to be catering to many industries from a range of tasks namely pick & place, material handling, as fixtures, tool & instrument holders etc. These application specific robots are equipped with end effectors customised with design appropriate for the application. In this paper, presented are the details for the design of an end effector also known as the gripper which works on a lead screw linear mechanism actuated by a dc motor. The gripper of stroke 100 mm is designed to hold bottles, tools or pick and place objects of rectangular section of 90mm x 90mm or of circular section of 90mm diameter and up to 3kg weight. Mechanical assembly comprises a sheet metal fixture plate holding the actuating components and a sheet metal gripper plate performing the gripping action. The motor is driven by a 24V, 2A dc motor driver. The gripping action is sensed and signalled by a force sensitive resistor. Prototype development of the gripper and on/off testing for the gripping action is investigated. The mechanical construction for this unique lead screw gripper is observed to be robust and can be used as an end effector to a suitable robotic arm.
Design of an industrial robotic gripper for precise twisting and positioning in high-speed assembly
In electronic manufacturing system, the design of the robotic hand is important for the successful accomplishment of the assembly task. Due to the restriction of the architecture of traditional robotic hands, it is difficult to grasp the cylinder shaped assembly parts with correct posture. In this research, a novel 4-DOF jaw like gripper is designed and built for precise positioning and twisting online. It can apply a constant gripping force on assembly parts and perform reliable twisting movement. Manipulating a cylinder shaped assembly part by robot, as an experimental case in this paper, is studied to evaluate the performance. The effectiveness of proposed gripper design and mechanical analysis is proved by the experiments.
Advanced Robotics, 2020
In this article, we propose a versatile robotic system for kitting and assembly tasks which uses no jigs or commercial tool changers. Instead of specialized end effectors, it uses its two-finger grippers to grasp and hold tools to perform subtasks such as screwing and suctioning. A third gripper is used as a precision picking and centering tool, and uses in-built passive compliance to compensate for small position errors and uncertainty. A novel grasp point detection for bin picking is described for the kitting task, using a single depth map. Using the proposed system we competed in the Assembly Challenge of the Industrial Robotics Category of the World Robot Challenge at the World Robot Summit 2018, obtaining 4th place and the SICE award for lean design and versatile tool use. We show the effectiveness of our approach through experiments performed during the competition.
A pivoting gripper for feeding industrial parts
Proceedings of the 1994 IEEE International Conference on Robotics and Automation
To be cost effective and highly precise, many industrial assembly robots have only four degrees of freedom (D.O.F.) plus a binary pneumatic gripper. Such robots commonly permit parts to be rotated only about a vertical axis. However it is often necessary to reorient parts about other axes prior to assembly. In this paper we describe a way to orient parts about an arbitrary axis by introducing a rotating bearing between the jaws of a simple gripper. Based on this mechanism, we are developing a rapidly configurable vision-based system for feeding parts. In this system, a camera determines initial part pose; the robot then reorients the part to achieve a desired final pose. We have implemented a prototype version in our laboratory using a commercially-available robot system.
Lecture Notes on Multidisciplinary Industrial Engineering, 2018
In today's era of mass customization, assembly automation systems should be designed with necessary production flexibility to cope with the growing product varieties to adapt to diverse customer requirements, yet the production costs should not be significantly different from those of comparable products made by mass production. In order to cope with this product variety-cost trade-off, robotics offers a flexible automation technology for turning assembly systems into efficient and flexible systems. Despite their great potential for high flexibility, there is a range of issues which must be addressed for its successful implementation. This chapter examines some of these key issues and challenges, reviews the results of previous research and describes our ongoing research on development of a flexible assembly system for mechanical products, using an industrial robot with machine vision guidance and dexterous multi-finger gripper. As part of the research work reported in this chapter, a Sexual Genetic Algorithm (SGA)-based approach for generation of optimal assembly sequence, a knowledge-based system for generating the robot task-level plan, a multi-finger robot gripper for flexible assembly based on a tendon-driven mechanism and an impedance control algorithm, and finally a strategy for implementation of robotic assembly under machine vision guidance have been presented.
A Hand Combining Two Simple Grippers to Pick Up and Arrange Objects for Assembly
IEEE robotics and automation letters, 2019
This paper proposes a novel robotic hand design for assembly tasks. The idea is to combine two simple grippers -an inner gripper which is used for precise alignment, and an outer gripper which is used for stable holding. Conventional robotic hands require complicated compliant mechanisms or complicated control strategy and force sensing to conduct assemble tasks, which makes them costly and difficult to pick and arrange small objects like screws or washers. Compared to the conventional hands, the proposed design provides a low-cost solution for aligning, picking up, and arranging various objects by taking advantages of the geometric constraints of the positioning fingers and gravity. It is able to deal with small screws and washers, and eliminate the position errors of cylindrical objects or objects with cylindrical holes. In the experiments, both real-world tasks and quantitative analysis are performed to validate the aligning, picking, and arrangements abilities of the design.
Automated robot-based screw insertion system
IECON 98, 1998
This paper introduces an automated robot-based system for the insertion of self-tapping screws into unthreaded holes. The system consists of three main components: a manipulator-guided screwdriver, a camera and a system which controls and monitors the overall process. The focus of this paper is on the key stages of the insertion procedure: a) detection of the insertion location by means of a camera, b) positioning of the electrical screwdriver employing a manipulator, and c) appropriately monitored insertion of a screw. Experiments were carried out in order to identify the requirements needed for a fully automated insertion system. Results are presented.
2014 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2014
In electronic manufacturing system, the design of the robotic hand with sufficient dexterity and configuration is important for the successful accomplishment of the assembly task. It is significant that the robot can grasp assembly parts and do some simple in-hand manipulation so as to fit them with the package slots. In this research, we study the process of precise in-hand posture transition problem using a novel jaw like gripper with human-sized anthropomorphic features. We transform the in-hand manipulation problem into a series of static grasping problems. Then we study the successful twisting condition on each grasp frame by analyzing its dynamic performance and requirements. Based on this data-driven idea, simulation and experimental data is obtained from both successful and failed trials. Finally, we create the distribution of parameters grasp map for successful twisting.
Robotized Assembly Process Using Dual Arm Robot
Procedia CIRP, 2014
This paper investigates into the use of a dual arm robot system for performing manual assembly operations. The investigation is based on a case study, originating from the final assembly area of an automotive assembly plant. The motivation as well as the benefits derived from the employment of a dual arm robot are discussed. The station layout, tooling design and robot programming are elaborated. The use of a dual arm robot enables the performance of operations that are carried out by humans, while the comparison of using single arm robots offers a number of advantages, which are discussed in the paper. The assembly of a vehicle dashboard is used as the use case coming from the automotive industry.
Robotic assembly : chamferless peg-hole assembly operation from X/Y/Z directions
2000
A great deal of research of the robotic peg-in hole assembly operation has evolved over the past decades. In the case of a chamfered peg-hole, it is normal to use a simple wrist such as the Remote Centre Compliance (RCC), which is fitted between the robot arm and the end effector to accommodate misalignments between the peg and the hole during the engagement stage. Otherwise jamming could occur and cause damage to the assembly robot and or the mating parts. However, in case of no chamfer on either of the mating parts, complicated and expensive devices are used to accommodate the same misalignments as the RCC. The objective of this research is to develop a new paSSIve assembly strategy and consequently a compliant wrist for the peg-hole insertion process. The wrist should adopt the passive technique as the RCC, but should accommodate positional errors even in case of no chamfer on either of the peg or the hole. Moreover, it should function from vertical as well as the horizontal dire...
Experimental studies of robotic assembly of precision parts
FME Transactions, 2021
At present, robotization of assembly processes is achieved through the use of industrial robots with high positioning accuracy in conjunction with tactile means of adaptation to the conditions of assembly of precision parts. The cost of such robots is many times higher than the cost of simple robots with low positioning accuracy of the robot arm. The research in this article is aimed at reducing the cost of assembly processes for precision parts by applying the position correction of the connected parts not by the robot hand, but by an additional technological module that is installed on the manipulator of a simple robot and performs high-speed stochastic mismatch scan of assembly objects. The article presents the results of a full factorial experiment of the process of joining precision cylindrical parts with a gap of no more than 3...5 microns. A regression model of this process is proposed, a formula for calculating the quasi-optimal modes of precision assembly and graphanalytica...
Unfastening of Hexagonal Headed Screws by a Collaborative Robot
IEEE Transactions on Automation Science and Engineering, 2020
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Designing a Mechanical Tool for Robots With Two-Finger Parallel Grippers
IEEE robotics and automation letters, 2019
This work designs a mechanical tool for robots with 2-finger parallel grippers, which extends the function of the robotic gripper without additional requirements on tool exchangers or other actuators. The fundamental kinematic structure of the mechanical tool is two symmetric parallelograms which transmit the motion of the robotic gripper to the mechanical tool. Four torsion springs are attached to the four inner joints of the two parallelograms to open the tool as the robotic gripper releases. The forces and transmission are analyzed in detail to make sure the tool reacts well with respect to the gripping forces and the spring stiffness. Also, based on the kinematic structure, variety tooltips were designed for the mechanical tool to perform various tasks. The kinematic structure can be a platform to apply various skillful gripper designs. The designed tool could be treated as a normal object and be picked up and used by automatically planned grasps. A robot may locate the tool through the AR markers attached to the tool body, grasp the tool by selecting an automatically planned grasp, and move the tool from any arbitrary pose to a specific pose to grip objects. The robot may also determine the optimal grasps and usage according to the requirements of given tasks.
High Reconfigurable Robotic Gripper for Flexible Assembly
This paper describes a general purpose gripper to be used into industrial manufacturing application. The gripper has been developed in the context of the AUTORECON project. It is based on a 2 degrees of freedom finger that is able to adapt itself to objects of various shape, size, material and weight. Thanks to its highly reconfigurable and adaptive capabilities, the gripper described here is an attempt to create a gripper suitable in industrial application to assemble compounds of several different workpieces using only one robot. The high dexterity and the wide range of possible uses of the gripper described here intends to explore a new approach to the design of industrial grippers to be used in factory automation. Moreover, the adaptive capabilities of this gripper make it suitable to grasp workpieces with complicated geometry or highly irregular shape, as it has been proved in performed automotive test rig described here.
Robotic assembly: chamferless peg-hole assembly
Robotica, 1999
The peg-in-hole insertion process is the most common task in the robotic/automatic assembly industry. However, the inaccuracy of the assembly robot in positioning the inserted peg into the hole due to the uncertainty of the assembly environment, represents an obstacle in this area of automation. To overcome this problem, complex and expensive equipment has been designed. The objective of this paper is to provide an in-depth understanding of the chamferless peg-hole assembly, by showing the geometrical, dynamical conditions for a successful assembly operation. Also, the results of this analysis have been simulated to demonstrate the chamferless peg-hole insertion process.
Haptics of Screwing and Unscrewing for Its Application in Smart Factories for Disassembly
Lecture Notes in Computer Science, 2018
Reconstruction of skilled humans sensation and control system often leads to a development of robust control for the robots. We are developing an unscrewing robot for the automated disassembly which requires a comprehensive control system, but unscrewing experiments with robots are often limited to several conditions. On the contrary, humans typically have a broad range of screwing experiences and sensations throughout their lives, and we conducted an experiment to find these haptic patterns. Results show that people apply axial force to the screws to avoid screwdriver slippage (cam-outs), which is one of the key problems during screwing and unscrewing, and this axial force is proportional to the torque which is required for screwing. We have found that type of the screw head influences the amount of axial force applied. Using this knowledge an unscrewing robot for the smart disassembly factory RecyBot is developed, and experiments confirm the optimality of the strategy, used by humans. Finally, a methodology for robust unscrewing algorithm design is presented as a generalization of the findings. It can seriously speed up the development of the screwing and unscrewing robots and tools.
Accomplishing task-invariant assembly strategies by means of an inherently accommodating robot arm
1997
Despite the fact that the main advantage of robot manipulators was always meant to be their flexibility, they have not been applied widely to the assembly of industrial components in situations other than those where hard automation might be used. We identify the two main reasons for this as the 'fragility' of robot operation during tasks that involve contact, and the lack of an appropriate user interface. This thesis describes an attempt to address these problems. We survey the techniques that have been proposed to bring the performance of cur¬ rent industrial robot manipulators in line with expectations, and conclude that the main obstacle in realising a flexible assembly robot that exhibits robust and reliable behaviour is the problem of spatial uncertainty. Based on observations of the performance of position-controlled robot manipulators and what is involved during rigid-body part mating, we propose a model of assembly tasks that exploits the shape invariance of the par...
A Double Jaw Hand Designed for Multi-Object Assembly
2018 IEEE-RAS 18th International Conference on Humanoid Robots (Humanoids), 2018
This paper presents a double jaw hand for industrial assembly. The hand comprises two orthogonal parallel grippers with different mechanisms. The inner gripper is made of a crank-slider mechanism which is compact and able to firmly hold objects like shafts. The outer gripper is made of a parallelogram that has large stroke to hold big objects like pulleys. The two grippers are connected by a prismatic joint along the hand's approaching vector. The hand is able to hold two objects and perform in-hand manipulation like pull-in (insertion) and push-out (ejection). This paper presents the detailed design and implementation of the hand, and demonstrates the advantages by performing experiments on two sets of peg-in-multi-hole assembly tasks as parts of the World Robot Challenge (WRC) 2018 a using a bimanual robot. Index Terms-Assembly, grippers, grasping, in-hand manipulation.
Manipulation of Boltlike Fasteners Through Fingertip Tactile Perception in Robotic Assembly
IEEE-ASME Transactions on Mechatronics, 2022
Robust manipulation of mechanical parts in different grasping configurations is a challenging problem in autonomous robotic assembly that can be overcome by adopting suitable mechatronic solutions. This article proposes a tactile-sensor-based approach that exploits inhand pose estimation and contact perception to compensate for unavoidable picking, placing, and insertion errors that may occur during task assembly execution under uncertain/perturbed conditions. The main objective of this work is to demonstrate how the use of tactile data, together with both machine learning and model-based methods, allows us to obtain an advanced system able to successfully complete a task that requires the manipulation of boltlike fasteners with different shapes and grasped in different poses. Experiments carried out using the proposed robotic system are reported for a specific assembly task in order to evaluate the effectiveness of the proposed solution. By means of suitable calibration procedures exploiting the same methods proposed here, the system can be easily adapted to different objects and shapes. Index Terms-Assembly robotic task, grasping pose estimation, tactile sensor. I. INTRODUCTION T HE evolution of industrial and manufacturing processes often requires robots to be involved in complex and highprecision manipulation tasks [1].