Index Finger of a Human-Like Robotic Hand Using Thin Soft Muscles

The application of solar drying (SD) and heat pump-assisted solar drying (HPSD) on the retention of flavonoid components, total color changes, and water activity of Clinacanthus nutans Lindau leaves were investigated. Analysis of data shows significantly higher extractable yield and flavonoid (orientin and vitexin) percentage during the drying with HPSD. The same drying technique also revealed optimum color values and low water activity. Thin-layer models fitted to the experimental data show that Hii and Law model is suitable for SD, while logarithmic model is able to give a good fit to HPSD

Hybrid extendable linear actuators: design and applications

There are many types of different actuators in the field of robotics. For applications where a linear displacement is required, a linear extendable actuator would be the method of choice. The hybrid class of extendable actuators possesses unique features making it suitable for many applications where the soft and rigid types fall short. However, there has not been a clear designation and classification of extendable linear hybrid actuators in the literature. This paper addresses this matter and provides the first overview of the hybrid class of extendable actuators. The paper performs a categorization and characterization of this class of extendable linear actuators based on their method of operation as well as the inherent unique features separating them from the rest. The paper contains five sections, and three sub-sections pertaining to the different categories of Hybrid actuators, and their applications. New research in this field continues to add features to this class of actuators through improvements and added capabilities

A Modular Bio-inspired Robotic Hand with High Sensitivity

While parallel grippers and multi-fingered robotic hands are well developed and commonly used in structured settings, it remains a challenge in robotics to design a highly articulated robotic hand that can be comparable to human hands to handle various daily manipulation and grasping tasks. Dexterity usually requires more actuators but also leads to a more sophisticated mechanism design and is more expensive to fabricate and maintain. Soft materials are able to provide compliance and safety when interacting with the physical world but are hard to model. This work presents a hybrid bio-inspired robotic hand that combines soft matters and rigid elements. Sensing is integrated into the rigid bodies resulting in a simple way for pose estimation with high sensitivity. The proposed hand is in a modular structure allowing for rapid fabrication and programming. The fabrication process is carefully designed so that a full hand can be made with low-cost materials and assembled in an efficient manner. We demonstrate the dexterity of the hand by successfully performing human grasp types.Comment: 7 pages, 13 figures, IEEE RoboSoft 202

Requirement Gathering Problems: Environmental Issues in Robot Development

This paper deals with the importance of environment consideration in developed countries while collecting the requirement from customer to make robot that would address the question “Why robots should be made more precisely according to the environment needs? “In developed countries, robots are used in manufacturing work as well as in performing the hazardous tasks such as bomb-disposal. So, there is a need to pay attention towards making the robots that can fit perfectly to some extent in environment to be utilized more efficiently. A lot of money, effort and time is spent on making the robots .But what if such a worth costing robot fails to fit in the operational environment? The best way to solve this problem is proposed in this paper which is to make the environment as a part of Requirement gathering process carrying high importance in robot making process to make the robots more Operational and suitable for the working environment .Like the other main attributes in requirement gathering process such as user requirements, system requirements and external requirements, there should be an attribute “Environmental requirements” which will automatically put emphasis on the considering also the environment as a main subject to  pay heed

3D-printed hierarchical arrangements of actuators mimicking biological muscular architectures

: Being able to imitate the sophisticated muscular architectures that characterize the animal kingdom in biomimetic machines would allow them to perform articulated movements with the same naturalness. In soft robotics, multiple actuation technologies have been developed to mimic the contraction of a single natural muscle, but a few of them can be implemented in complex architectures capable of diversifying deformations and forces. In this work, we present three different biomimetic muscle architectures, i.e., fusiform, parallel, and bipennate, which are based on hierarchical arrangements of multiple pneumatic actuators. These biomimetic architectures are monolithic structures composed of thirty-six pneumatic actuators each, directly 3D printed through low-cost printers and commercial materials without any assembly phase. The considerable number of actuators involved enabled the adoption and consequent comparison of two regulation strategies: one based on input modulation, commonly adopted in pneumatic systems, and one based on fiber recruitment, mimicking the regulation behavior of natural muscles. The straightforward realization through additive manufacturing processes of muscle architectures regulated by fiber recruitment strategies facilitates the development of articulated muscular systems for biomimetics machines increasingly similar to the natural ones

Pulley-based McKibben actuator mechanism for adjustable soft hand rehabilitation splint

Hand rehabilitation robots were developed to assist in rehabilitation procedures conducted by rehabilitation professionals. However, current hand rehabilitation robots are mostly made from heavy and rigid structures that caused discomfort and fitting issues to the patients. McKibben actuator is a type of soft actuator that could be used in hand rehabilitation robots for its flexibility and light weight. However, it has a limited contraction ratio for the required range of motion for finger flexion. In this thesis, a pulley mechanism is proposed to improve McKibben actuator’s contraction ratio while providing the required contraction force. A double groove pulley made of a hybrid of gear and pulley is proposed to enhance McKibben’s actuator contraction ratio. Various pulley ratio was studied to find optimum contraction ratio and its relation to contraction force. A pulley ratio of 1:4 increases the contraction ratio from 19.85 % to 76.67 % but reduces the contraction force from 42.68 N to 9.69 N. Hence, pulley ratio of 1:2 was implemented to the McKibben linear actuator based on its optimized 39.72 % contraction ratio and 20 N contraction force for the soft splint application. Next, an adjustable finger size soft splint with fixed wrist motion was developed. It consists of three parts, namely pulley-based McKibben actuator, wrist component, and McKibben ring actuators. The wrist component was designed with an adjustable strap buckle while the finger insertion part utilized the elasticity of McKibben ring actuator during contraction to fit a wide range of sizes. The size range for wrist and hand circumference is 12 cm - 21.6 cm and 15.8 cm - 22.3 cm respectively, which fit 90 % of Malaysian young adults. The soft splint was tested on two healthy subjects. At 400 kPa supply pressure, the bending angle of the finger joints achieved was [71.8°, 72.8°, 18.70] for Metacarpophalangeal, Proximal Interphalangeal and Distal Interphalangeal respectively. The range of motion achieved by the soft splint is lower than the functional range of motion, but higher compared to other research works. The subjects were able to grasp and lift objects of different shapes including a box, cylinder, and irregular shape under 250 g while wearing the soft splint. The developed soft splint with adjustable McKibben ring actuators and pulley-based McKibben linear actuator could initiate finger motion and assist object grasping for a possible clinical hand rehabilitation assessment

A hybrid, wearable exoskeleton glove equipped with variable stiffness joints, abduction capabilities, and a telescopic thumb

Robotic hand exoskeletons have become a popular and efficient technological solution for assisting people that suffer from neurological conditions and for enhancing the capabilities of healthy individuals. This class of devices ranges from rigid and complex structures to soft, lightweight, wearable gloves. In this work, we propose a hybrid (tendon-driven and pneumatic), lightweight, affordable, easy-to-operate exoskeleton glove equipped with variable stiffness, laminar jamming structures, abduction/adduction capabilities, and a pneumatic telescopic extra thumb that increases grasp stability. The efficiency of the proposed device is experimentally validated through five different types of experiments: i) abduction/adduction tests, ii) force exertion experiments that capture the forces that can be exerted by the proposed device under different conditions, iii) bending profile experiments that evaluate the effect of the laminar jamming structures on the way the fingers bend, iv) grasp quality assessment experiments that focus on the effect of the inflatable thumb on enhancing grasp stability, and v) grasping experiments involving everyday objects and seven subjects. The hybrid assistive, exoskeleton glove considerably improves the grasping capabilities of the user, being able to exert the forces required to execute a plethora of activities of daily living. All files that allow the replication of the device are distributed in an open-source manner

An anthropomorphic robotic finger with innate human-finger-like biomechanical advantages part II : flexible tendon sheath and grasping demonstration

The human hand has a fantastic ability to interact with various objects in the dynamic unstructured environment of our daily activities. We believe that this outstanding performance benefits a lot from the unique biological features of the hand musculoskeletal system. In Part I of this article, a bio-inspired anthropomorphic robotic finger was developed, based on which two human-finger-like biomechanical advantages were elaborately investigated, including the anisotropic variable stiffness associated with the ligamentous joints and the enlarged feasible force space associated with the reticular extensor mechanisms. In Part II, the fingertip force-velocity characteristics resulting from the flexible tendon sheath are studied. It indicates that the fingertip force–velocity workspace can be greatly augmented owing to the self-adaptive morphing of the flexible tendon sheaths, showing the average improvement of 41.2% theoretically and 117.5% experimentally compared with the results of 2 mm, 4 mm, and 6 mm size rigid tendon sheaths. Grasping tests and comparisons are then conducted with four three-fingered robotic hands (one with the robotic finger proposed in Part I, one with hinge joints, one with linear extensors, and one with rigid tendon sheaths) and the human hands of six subjects to handle various objects on flat, rough, and soft surfaces. The results show that the novel bio-inspired design in this research could improve the grasping success rates of the robotic hand. Compared with the grasping test results from the robotic hand with the bio-inspired robotic finger proposed in Part I, the overall grasping performance of a robotic hand with hinge joints, linear extensors, and rigid tendon sheaths decreases by 10%, 6%, and 17%, respectively. The results have also shown that with the embedded biomechanical advantages, even without complex control and sensory systems, the robotic fingers can achieve very comparable performance to human fingers in the grasping demonstrations presented, indicating average 94% of the success rate achieved by the human fingers. Successfully demonstrating 14 of 16 grasp types in the Cutkoskey taxonomy further shows the human-finger-like grasping capability of the proposed robotic fingers