scholarly journals 3D Printed Robot Hand Structure Using Four-Bar Linkage Mechanism for Prosthetic Application

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4174 ◽  
Author(s):  
Mohamad Aizat Abdul Wahit ◽  
Siti Anom Ahmad ◽  
Mohammad Hamiruce Marhaban ◽  
Chikamune Wada ◽  
Lila Iznita Izhar
Keyword(s):  
Load Test ◽  
Human Hand ◽  
Robot Hand ◽  
Linkage Mechanism ◽  
Design Problems ◽  
Joint Protection ◽  
Structural Details ◽  
Motion Range ◽  
3D Printed ◽  
Four Bar Linkage

Trans-radial prosthesis is a wearable device that intends to help amputees under the elbow to replace the function of the missing anatomical segment that resembles an actual human hand. However, there are some challenging aspects faced mainly on the robot hand structural design itself. Improvements are needed as this is closely related to structure efficiency. This paper proposes a robot hand structure with improved features (four-bar linkage mechanism) to overcome the deficiency of using the cable-driven actuated mechanism that leads to less structure durability and inaccurate motion range. Our proposed robot hand structure also took into account the existing design problems such as bulky structure, unindividual actuated finger, incomplete fingers and a lack of finger joints compared to the actual finger in its design. This paper presents the improvements achieved by applying the proposed design such as the use of a four-bar linkage mechanism instead of using the cable-driven mechanism, the size of an average human hand, five-fingers with completed joints where each finger is moved by motor individually, joint protection using a mechanical stopper, detachable finger structure from the palm frame, a structure that has sufficient durability for everyday use and an easy to fabricate structure using 3D printing technology. The four-bar linkage mechanism is the use of the solid linkage that connects the actuator with the structure to allow the structure to move. The durability was investigated using static analysis simulation. The structural details and simulation results were validated through motion capture analysis and load test. The motion analyses towards the 3D printed robot structure show 70–98% similar motion range capability to the designed structure in the CAD software, and it can withstand up to 1.6 kg load in the simulation and the real test. The improved robot hand structure with optimum durability for prosthetic uses was successfully developed.

scholarly journals Development of a humanoid robot hand with coupling four-bar linkage

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668631 ◽  
Author(s):  
Xinhua Liu ◽  
Xianhua Zheng ◽  
Shengpeng Li
Keyword(s):  
Humanoid Robot ◽  
Three Dimensional ◽  
Human Hand ◽  
Robot Hand ◽  
End Effector ◽  
Kinematics Simulation ◽  
Contact Kinematics ◽  
Motion Range ◽  
Four Bar Linkage ◽  
The Mathematical Model

To improve the operating performance of robots’ end-effector, a humanoid robot hand based on coupling four-bar linkage was designed. An improved transmission system was proposed for the base joint of the thumb. Thus, a far greater motion range and more reasonable layout of the palm were obtained. Moreover, the mathematical model for kinematics simulation was presented based on the Assur linkage group theory to verify and optimize the proposed structure. To research the motion relationships between the fingers and the object in the process of grasping object, the grasping analysis of multi-finger manipulation was presented based on contact kinematics. Finally, a prototype of the humanoid robot hand was produced by a three-dimensional printer, and a kinematics simulation example and the workspace solving of the humanoid robot hand were carried out. The results showed that the velocities of finger joints approximately met the proportion relationship 1:1:1, which accorded with the grasping law of the human hand. In addition, the large workspace, reasonable layout, and good manipulability of the humanoid robot hand were verified.

scholarly journals Customization of a 3D Printed Prosthetic Finger Using Parametric Modeling

2018 ◽  
Author(s):  
Daniel Lim ◽  
Thomás Georgiou ◽  
Aashish Bhardwaj ◽  
Grace D. O’Connell ◽  
Alice M. Agogino
Keyword(s):  
Mechanical Design ◽  
Parametric Modeling ◽  
Width Ratio ◽  
Linkage Mechanism ◽  
Prosthetic Limbs ◽  
3D Printed ◽  
Finger Width ◽  
Prosthetic Finger ◽  
Finger Tip ◽  
Four Bar Linkage

Prosthetic limbs and assistive devices require customization to effectively meet the needs of users. Despite the expense and hassle involved in procuring a prosthetic, 56% of people with limb loss end up abandoning their devices [1]. Acceptance of these devices is contingent on the comfort of the user, which depends heavily on the size, weight, and overall aesthetic of the device. As seen in numerous applications, parametric modeling can be utilized to produce medical devices that are specific to the patient’s needs. However, current 3D printed upper limb prosthetics use uniform scaling to fit the prostheses to different users. In this paper, we propose a parametric modeling method for designing prosthetic fingers. We show that a prosthetic finger designed using parametric modeling has a range of motion (ROM) (path of the finger tip) that closely aligns with the digit’s natural path. We also show that the ROM produced by a uniformly scaled prosthetic poorly matches the natural ROM of the finger. To test this, finger width and length measurements were collected from 50 adults between the ages of 18–30. It was determined that there is negligible correlation between the length and width of the index (D2) digit among the participants. Using both the highest and the lowest length to width ratio found among the participants, a prosthetic finger was designed using a parametric model and fabricated using additive manufacturing. The mechanical design of the prosthetic finger utilized a crossed four bar linkage mechanism and its ROM was determined by Freudenstein’s equations. By simulating the different paths of the fingers, we demonstrate that parametrically modeled fingers outperform uniformly scaled fingers at matching a natural digit’s path.

scholarly journals Development of Real-Time Electromyography Controlled 3D Printed Robot Hand Prototype

2019 ◽  
Vol 10 (1) ◽  
pp. 35-44
Author(s):  
Mohamad Aizat Abdul Wahit ◽  
Fatimahtul Zahrah Romzi ◽  
Siti Anom Ahmad ◽  
Mohd Hamiruce Marhaban ◽  
Wada Chikamune
Keyword(s):  
Structural Design ◽  
Control Method ◽  
Muscular Activity ◽  
Movement Control ◽  
Research Field ◽  
Human Hand ◽  
Robotic Hand ◽  
Robot Hand ◽  
3D Printed ◽  
Average Size

Developing an anthropomorphic robotic hand (ARH) has become a relevant research field due to the need to help the amputees live their life as normal people. However, the current state of research is unsatisfactory, especially in terms of structural design and the robot control method. This paper, which proposes a 3D printed ARH structure that follows the average size of an adult human hand, consists of five fingers with a tendon-driven actuator mechanism embedded in each finger structure. Besides that, the movement capability of the developed 3D printed robot hand validated by using motion capture analysis to ensure the similarity to the expected motion range in structural design is achieved. Its system functionality test was conducted in three stages: (1) muscular activity detection, (2) object detection for individual finger movement control, and (3) integration of both stages in one algorithm. Finally, an ARH was developed, which resembles human hand features, as well as a reliable system that can perform opened hand palm and some grasping postures for daily use.

A Fully 3D‐Printed Wearable Piezoresistive Strain and Tactile Sensing Array for Robot Hand

2021 ◽  
pp. 2100038
Author(s):  
Zhen Pei ◽  
Qiang Zhang ◽  
Kun Yang ◽  
Zhongyun Yuan ◽  
Wendong Zhang ◽  
...  
Keyword(s):  
Tactile Sensing ◽  
Robot Hand ◽  
3D Printed

Optimal Control of a Flexible Mechanism Using a Combined Feedforward-Feedback Strategy: Simulation and Experiment

1999 ◽  
Author(s):  
Hubertus v. Stein ◽  
Heinz Ulbrich
Keyword(s):  
Optimal Control ◽  
Control Strategy ◽  
System Performance ◽  
High Speed ◽  
Time Varying ◽  
Linkage Mechanism ◽  
Additional Degree ◽  
Control Approach ◽  
Feedback Optimal Control ◽  
Four Bar Linkage

Abstract Due to the elasticity of the links in modern high speed mechanisms, increasing operating speeds often lead to undesirable vibrations, which may render a required accuracy unattainable or, even worse, lead to a failure of the whole process. The dynamic effects e.g. may lead to intolerable deviations from the reference path or even to the instability of the system. Instead of suppressing the vibration by a stiffer design, active control methods may greatly improve the system performance and lead the way to a reduction of the mechanism’s weight. We investigate a four-bar-linkage mechanism and show that by introducing an additional degree of freedom for a controlled actuator and providing a suitable control strategy, the dynamically induced inaccuracies can be substantially reduced. The modelling of the four-bar-linkage mechanism as a hybrid multi body system and the modelling of the complete system (including the actuator) is briefly explained. From the combined feedforward-feedback optimal control approach presented in (v. Stein, Ulbrich, 1998) a time-varying output control law is derived that leads to a very good system performance for this linear discrete time-varying system. The experimental results show the effectiveness of the applied control strategy.

scholarly journals Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli , an ancient apex predator

2006 ◽  
Vol 3 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Philip S.L Anderson ◽  
Mark W Westneat
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Mouth Opening ◽  
Biomechanical Model ◽  
Bite Force ◽  
Rapid Expansion ◽  
Large Individual ◽  
Linkage Mechanism ◽  
Feeding Mechanics ◽  
Four Bar Linkage

Placoderms are a diverse group of armoured fishes that dominated the aquatic ecosystems of the Devonian Period, 415–360 million years ago. The bladed jaws of predators such as Dunkleosteus suggest that these animals were the first vertebrates to use rapid mouth opening and a powerful bite to capture and fragment evasive prey items prior to ingestion. Here, we develop a biomechanical model of force and motion during feeding in Dunkleosteus terrelli that reveals a highly kinetic skull driven by a unique four-bar linkage mechanism. The linkage system has a high-speed transmission for jaw opening, producing a rapid expansion phase similar to modern fishes that use suction during prey capture. Jaw closing muscles power an extraordinarily strong bite, with an estimated maximal bite force of over 4400 N at the jaw tip and more than 5300 N at the rear dental plates, for a large individual (6 m in total length). This bite force capability is the greatest of all living or fossil fishes and is among the most powerful bites in animals.

Miniaturized Pneumatic Artificial Muscles Actuating a Bio-Inspired Robot Hand

2013 ◽  
Author(s):  
Thomas E. Pillsbury ◽  
Ryan M. Robinson ◽  
Norman M. Wereley
Keyword(s):  
Degrees Of Freedom ◽  
Full Scale ◽  
Constitutive Relationship ◽  
Force Density ◽  
Human Hand ◽  
Artificial Muscles ◽  
Specific Work ◽  
Robotic Hand ◽  
Robot Hand ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are used in robotics applications for their light-weight design and superior static performance. Additional PAM benefits are high specific work, high force density, simple design, and long fatigue life. Previous use of PAMs in robotics research has focused on using “large,” full-scale PAMs as actuators. Large PAMs work well for applications with large working volumes that require high force and torque outputs, such as robotic arms. However, in the case of a compact robotic hand, a large number of degrees of freedom are required. A human hand has 35 muscles, so for similar functionality, a robot hand needs a similar number of actuators that must fit in a small volume. Therefore, using full scale PAMs to actuate a robot hand requires a large volume which for robotics and prosthetics applications is not feasible, and smaller actuators, such as miniature PAMs, must be used. In order to develop a miniature PAM capable of producing the forces and contractions needed in a robotic hand, different braid and bladder material combinations were characterized to determine the load stroke profiles. Through this characterization, miniature PAMs were shown to have comparably high force density with the benefit of reduced actuator volume when compared to full scale PAMs. Testing also showed that braid-bladder interactions have an important effect at this scale, which cannot be modeled sufficiently using existing methods without resorting to a higher-order constitutive relationship. Due to the model inaccuracies and the limited selection of commercially available materials at this scale, custom molded bladders were created. PAMs created with these thin, soft bladders exhibited greatly improved performance.

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