Active Vibration Fluidization for Granular Jamming Grippers

Granular jamming has recently become popular in soft robotics with widespread applications including industrial gripping, surgical robotics and haptics. Previous work has investigated the use of various techniques that exploit the nature of granular physics to improve jamming performance, however this is generally underrepresented in the literature compared to its potential impact. We present the first research that exploits vibration-based fluidisation actively (e.g., during a grip) to elicit bespoke performance from granular jamming grippers. We augment a conventional universal gripper with a computer-controllled audio exciter, which is attached to the gripper via a 3D printed mount, and build an automated test rig to allow large-scale data collection to explore the effects of active vibration. We show that vibration in soft jamming grippers can improve holding strength. In a series of studies, we show that frequency and amplitude of the waveforms are key determinants to performance, and that jamming performance is also dependent on temporal properties of the induced waveform. We hope to encourage further study focused on active vibrational control of jamming in soft robotics to improve performance and increase diversity of potential applications.Comment: arXiv admin note: substantial text overlap with arXiv:2109.1049

Novel Adaptive Gripping Device for Tasks Requiring Fine Motor Control

Fine motor control is essential for a student’s success in school, and beneficial for their independence and quality of life. A C6 spinal cord injury left our client with a severe lack of fine motor control and complete paralysis below his shoulders. The goal of this project was to design and produce a novel device to aid the user in performing tasks requiring fine motor control in order to increase his independence. There are no current devices available that fit our client’s specific need. A device was designed to be lightweight, portable, easy to use, and purely mechanical. It was shown to be successful through a series of tests, allowing the client to complete tasks requiring fine motor control more quickly and efficiently than before, increasing his independence and quality of life

Proceedings of the 4th Baltic Mechatronics Symposium - Tallinn April 25, 2019

The Baltic Mechatronics Symposium is annual symposium with the objective to provide a forum for young scientists from Baltic countries to exchange knowledge, experience, results and information in large variety of fields in mechatronics. The symposium was organized in co-operation with Taltech and Aalto University. The venue of the symposium was Nordic Hotel Forum Tallinn.The symposium was organized parallel to the 12th International DAAAM Baltic Conference and 27th International Baltic Conference BALTMATTRIB 2019. The selected papers are published in Proceedings of Estonian Academy of Sciences indexed in ISI Web of Science. The content of the proceedings: 1. Continuous wet spinning of cellulose nanofibrils 2. Development of motor efficiency test setup for direct driven hydraulic actuator 3. Development of pressure former for continuous nanopaper manufacturing 4. Device for tree volume measurements 5. Effect of external load on rotor vibration 6. Granular jamming based gripper for heavy objects 7. Integrated car camera system for monitoring inner cabin and outer traffic 8. Inverted pendulum controlled with CNC control system 9. Multi-material mixer and extruder for 3D printing 10. Object detection and trajectory planning using a LIDAR for an automated overhead cran

The design and development of an artificial hand incorporating function and cosmesis

The thesis presents some of the work carried out as part of the research and development programme for the provision of practical artificial upper limbs for a group of congenital amputee patients. The account commences by reviewing, in Volume 1, the problems presented by this population of amputees in the context of an ongoing limb fitting service, and shows hoer the difficulties of prehension arise in this situation. The provision of upper limb prostheses in general is then reviewed with reference to representative literature on the subject, where various inadequacies of existing systems are considered in the context of the immediate practical problem of the provision of adequate prehension facilities for bilateral amputees. The experimental and practical work of Volume 2 commences with an appraisal of the requirements for a hand prosthesis in the light of the information derived from Volume Is, and this, together with the results of some simple experiments, leads to a broad specification for a hand mechanism. Various experimental mechanisms are then described, leading to the development of a mechanism suitable for patient trials. The problem of the provision of the cosmetic cover for the mechanism emerges as the major obstacle in the way of further progress, and a new process for cosmetic glove production is devised, This is followed by consideration of the various problems of control associated with the hand prosthesis, some working hardware is developed and guidelines for future work on control are outlined. The thesis concludes with an appraisal of the work following trial fittings on patients, which shows the principles to be successful in Operation and indications for future trends are given in the context of a wider amputee population who may benefit from some aspects of the work

Design and Development of a Soft Robotic Gripper for Fabric Material Handling

Fabric and textile materials are widely used in many industrial applications, especially in automotive, aviation and consumer goods. Currently, there is no semi-automatic or automatic solution for rapid, effective, and reconfigurable pick and place activities for limp, air permeable flexible components in industry. The production of these light-weight flexible textile or composite fiber products highly rely on manual operations, which lead to high production costs, workplace safety issues, and process bottlenecks. As a bio-inspired novel technology, soft robotic grippers provide new opportunities for the automation of fabric handling tasks. In this research, the characteristics of fabric pick and place tasks using the clamping grippers are quantitatively investigated. Experiments on a carbon fiber fabric are performed with a collaborative robot to explore the damage, slippage, draping, and wrinkling during basic pick and place operations. Based on the experimental results, multiple soft robotic gripper configurations are developed, including a compliant glove set that can improve the performance of traditional rigid grippers, an elastomer-based soft gripper, and a linkage-based underactuated gripper. The gripper designs are analyzed and refined based on finite element simulation. Prototypes of the grippers are fabricated using a rapid tooling solution for an overmolding strategy to verify their functionality. Through the research, it is proven feasible to reliably perform flexible fabric handling operations using soft grippers with appropriate toolpath planning. Finite element simulation and additive manufacturing have shown to be useful tools during the gripper design and development procedure, and the methodologies developed and applied in this work should be expanded for more flexible material handling challenges

Fabric-based eversion type soft actuators for robotic grasping applications

Humans have managed to simplify their lives by using robots to automate dull and repetitive tasks. Traditional robots have been very helpful in this respect, but in certain applications, the complexity of manufacturing and the requisite control strategies have rendered these systems inadequate. The concept of robots made of soft materials has increasingly been explored and a new avenue of research has opened up within the robotics community. In terms of construction, robots made of soft and flexible materials have several advantages over their rigid-bodied counterparts, among them simple design, simple control mechanisms, inexpensive constituent materials and the fact that they can be easily integrated into existing systems. Soft grippers in particular have been the subject of extensive research and we have witnessed significant development in terms of attributes like grasping, payload and sensing methodologies. Progress has been enhanced by the development of new materials used in the construction of actuators or end effectors of the grippers. The use of lightweight, non-stretch fabrics is a relatively new concept but initial studies have demonstrated their effectiveness in grasping applications. This thesis sets out a comparative study of popular gripping systems, focusing on the advantages of using fabrics in the construction of soft grippers. Multiple designs for fabric based finger like actuators, each addressing the drawbacks of the preceding design, are discussed along with the experimental evaluation of each design. A novel gripping mechanism in which the fingers of the gripper grow lengthwise from the tip (evert) to access and grasp the object is also presented. Large-scale fabric based eversion robots have been constructed to access environments with restricted access and for monitoring purposes. An experimental evaluation of the eversion capable finger is also presented, outlining important attributes such as payload, bending and force capability of the designed finger. An optical fibre based sensing methodology is also presented, capable of measuring the bending behaviour in soft actuators. The proposed sensor can be configured to sense bending angles, as well as the contact forces along different points along the length of the actuators

Dexterous grippers: between simple industrial grippers and complex robotic hands

This thesis addresses the issue of introducing dexterity, namely the ability to manipulate objects in hand, into simple mechanical grippers. Among the many possibilities to give dexterity to a gripping device we opted to intervene at the finger-pad surface since it is the part of the end effector directly in contact with the object to be manipulated. The first contribution is the development of an under-actuated gripper with Active Surfaces on the inner side of the fingers which allow to in-hand manipulate the grasped objects. The gripper, named Velvet Fingers, was designed from the theoretical concepts, manufactured, assembled and then turned into an applicative scenario. A second main contribution of this thesis, carried out in collaboration with AASS Research Center, of the University of \"Orebro (Sweden), is a grasp execution routine using the Active Surfaces of the Velvet Fingers to achieve a robust power grasp starting from an initial fingertip grasp. This routine is very useful and effective in cluttered environment where an initial fingertip grasp is much more likely to be feasible than a bulky power grasp. The third main contribution is the development of a small gripper for small household objects such as cans, small bottles, little boxes, tennis balls etc. This gripper, named Velvet-II, is able to perform in-hand manipulation tasks, to elicit information from the grasped object, namely the contact point location and the components of the grasping forces and to detect incipient slippage between the gripper and the object. Within a collaboration with AASS Research Center the gripper has been employed on a robotic platform for autonomous picking and palletizing

Design of a non-invasive device to measure bone strength recovery of distal radius fractures for use with HR-pQCT Imaging

Distal radius fractures are the most common bone injury in adults, with the majority occurring in postmenopausal women. Often these fractures result in painful healing defects, leading to extended treatment and even surgery. Currently, there is no clinical method to quantify the extent of bone healing beyond the limited capabilities of standard x-rays. The goal of this project is to develop a device, which can determine the strength of a healing fracture. This is achieved by applying a known bending load to the distal radius and measuring the displacement of the bone in High Resolution CT images. The device created was manufactured via 3D printing. Validation of device performance was performed using cadaver wrist models

Research and development of a reconfigurable robotic end-effector for machining and part handling.

Masters Degree. University of KwaZulu-Natal, Durban.Abstract available in PDF