scholarly journals Topological Analysis of a Novel Compact Omnidirectional Three-Legged Robot with Parallel Hip Structures Regarding Locomotion Capability and Load Distribution

Robotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 117
Author(s):  
David Feller ◽  
Christian Siemers
Keyword(s):  
Degrees Of Freedom ◽  
Topological Analysis ◽  
Legged Robot ◽  
Spherical Parallel Mechanism ◽  
Cad Models ◽  
Central Support ◽  
3D Printed ◽  
Multi Body ◽  
Spherical Parallel Manipulator ◽  
Novel Design

In this study, a novel design for a compact, lightweight, agile, omnidirectional three-legged robot involving legs with four degrees of freedom, utilizing an spherical parallel mechanism with an additional non-redundant central support joint for the robot hip structure is proposed. The general design and conceptual ideas for the robot are presented, targeting a close match of the well-known SLIP-model. CAD models, 3d-printed prototypes, and proof-of-concept multi-body simulations are shown, investigating the feasibility to employ a geometrically dense spherical parallel manipulator with completely spherically shaped shell-type parts for the highly force-loaded application in the legged robot hip mechanism. Furthermore, in this study, an analytic expression is derived, yielding the calculation of stress forces acting inside the linkage structures, by directly constructing the manipulator hip Jacobian inside the force domain.

scholarly journals Musculoskeletal System for Bio-Inspired Robotic Systems

2016 ◽  
Vol 138 (03) ◽  
pp. S11-S16 ◽  
Author(s):  
Yonas Tadesse ◽  
Lianjun Wu ◽  
Lokesh K. Saharan
Keyword(s):  
Musculoskeletal System ◽  
System Integration ◽  
Degrees Of Freedom ◽  
Manufacturing System ◽  
Biological Systems ◽  
Robotic Systems ◽  
Energy Usage ◽  
3D Printed ◽  
Musculoskeletal Systems ◽  
Novel Design

This article presents a research focused on developing musculoskeletal system for bio-inspired robotic systems. A musculoskeletal system is the fundamental structure that allows complex mobility of biological systems. This paper briefly describes the recently introduced twisted and coiled polymer (TCP) muscles and a novel design of musculoskeletal system based on ball and socket joint, as well as their application in a 3D printed humanoid robot. The challenge to develop such systems is multifaceted, including design, manufacturing, system integration, control methods, and energy usage. Some of the challenges in humanoid design are the degrees of freedom and the synergetic combination of hardware and software to perform a particular task. The other challenge is affordability of the platform. Most humanoids are very expensive. Since the TCP-based actuators are inexpensive and musculoskeletal systems inspired by biological systems are optimum for performance, they will address these problems. The bio-inspired ball and socket joint shown in the article can be cascaded to create complex robots, for example, for the shoulder joint of a humanoid.

scholarly journals Torque Reduction of a Reconfigurable Spherical Parallel Mechanism Based on Craniotomy Experimental Data

2021 ◽  
Vol 11 (14) ◽  
pp. 6534
Author(s):  
Terence Essomba ◽  
Juan Sandoval ◽  
Med Amine Laribi ◽  
Chieh-Tsai Wu ◽  
Cyril Breque ◽  
...  
Keyword(s):  
Motion Capture ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Human Cadaver ◽  
Drilling Tool ◽  
Force Interaction ◽  
Spherical Parallel Mechanism ◽  
Angle Modulation ◽  
Spherical Parallel Manipulator

This paper deals with a robotic manipulator dedicated to craniotomy with a remote center of motion based on a Spherical Parallel Manipulator (SPM) architecture. The SPM is proposed to handle the drilling tool through the requested craniotomy Degrees of Freedom (DoF) with two rotations. The proposed architecture allows one degree of redundancy according to the total DoF. Thus, a first contribution of this work focuses on the experimental analysis of craniotomy surgery tasks. Secondly, its behavior is improved, taking advantage of the redundancy of the SPM using the spinning motion as a reconfiguration variable. The spinning angle modulation allows the reconfigurable manipulator to minimize its motor torques. A series of motion capture and force experimentations is performed for the analysis of the kinematic and force interaction characterizing Burr hole craniotomy procedures. Experimentations were carried out by a neurosurgeon on a human cadaver, ensuring highly realistic conditions.

scholarly journals Design and Analysis of a Multi-Legged Robot with Pitch Adjustive Units

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Qiang Ruan ◽  
Jianxu Wu ◽  
Yan-an Yao
Keyword(s):  
Complex Terrain ◽  
Degrees Of Freedom ◽  
Virtual Model ◽  
Legged Robot ◽  
Dynamic Simulations ◽  
Compact Structure ◽  
Multi Body ◽  
6 Degrees Of Freedom ◽  
Body Dynamic ◽  
Pitch Adjustment

AbstractThe paper proposes a novel multi-legged robot with pitch adjustive units aiming at obstacle surmounting. With only 6 degrees of freedom, the robot with 16 mechanical legs walks steadily and surmounts the obstacles on the complex terrain. The leg unit with adjustive pitch provides a large workspace and empowers the legs to climb up obstacles in large sizes, which enhances the obstacle surmounting capability. The pitch adjustment in leg unit requires as few independent adjusting actuators as possible. Based on the kinematic analysis of the mechanical leg, the biped and quadruped leg units with adjustive pitch are analyzed and compared. The configuration of the robot is designed to obtain a compact structure and pragmatic performance. The uncertainty of the obstacle size and position in the surmounting process is taken into consideration and the parameters of the adjustments and the feasible strategies for obstacle surmounting are presented. Then the 3D virtual model and the robot prototype are built and the multi-body dynamic simulations and prototype experiments are carried out. The results from the simulations and the experiments show that the robot possesses good obstacle surmounting capabilities.

scholarly journals A millifluidic chip for cultivation of fish embryos and toxicity testing fabricated by 3D printing technology

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20507-20518
Author(s):  
Petr Panuška ◽  
Zuzana Nejedlá ◽  
Jiří Smejkal ◽  
Petr Aubrecht ◽  
Michaela Liegertová ◽  
...  
Keyword(s):  
3D Printing ◽  
Toxicity Testing ◽  
Toxicity Screening ◽  
Printing Technology ◽  
3D Printing Technology ◽  
Fish Embryos ◽  
3D Printed ◽  
Novel Design

A novel design of 3D printed zebrafish millifluidic system for embryonic long-term cultivation and toxicity screening has been developed. The chip unit provides 24 cultivation chambers and a selective individual embryo removal functionality.

scholarly journals Tablet fragmentation without a disintegrant: A novel design approach for accelerating disintegration and drug release from 3D printed cellulosic tablets

2018 ◽  
Vol 118 ◽  
pp. 191-199 ◽  
Author(s):  
Basel Arafat ◽  
Magdalena Wojsz ◽  
Abdullah Isreb ◽  
Robert T. Forbes ◽  
Mohammad Isreb ◽  
...  
Keyword(s):  
Drug Release ◽  
Design Approach ◽  
3D Printed ◽  
Novel Design

A scalable mass customisation design process for 3D-printed respirator mask to combat COVID-19

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shiya Li ◽  
Usman Waheed ◽  
Mohanad Bahshwan ◽  
Louis Zizhao Wang ◽  
Livia Mariadaria Kalossaka ◽  
...  
Keyword(s):  
Design Process ◽  
Acquisition Time ◽  
Geometric Accuracy ◽  
Depth Sensor ◽  
Content Type ◽  
Mass Customisation ◽  
Equipment Cost ◽  
Cad Models ◽  
3D Printed ◽  
Acquisition Method

Purpose A three-dimensional (3D) printed custom-fit respirator mask has been proposed as a promising solution to alleviate mask-related injuries and supply shortages during COVID-19. However, creating a custom-fit computer-aided design (CAD) model for each mask is currently a manual process and thereby not scalable for a pandemic crisis. This paper aims to develop a novel design process to reduce overall design cost and time, thus enabling the mass customisation of 3D printed respirator masks. Design/methodology/approach Four data acquisition methods were used to collect 3D facial data from five volunteers. Geometric accuracy, equipment cost and acquisition time of each method were evaluated to identify the most suitable acquisition method for a pandemic crisis. Subsequently, a novel three-step design process was developed and scripted to generate respirator mask CAD models for each volunteer. Computational time was evaluated and geometric accuracy of the masks was evaluated via one-sided Hausdorff distance. Findings Respirator masks were successfully generated from all meshes, taking <2 min/mask for meshes of 50,000∼100,000 vertices and <4 min for meshes of ∼500,000 vertices. The average geometric accuracy of the mask ranged from 0.3 mm to 1.35 mm, depending on the acquisition method. The average geometric accuracy of mesh obtained from different acquisition methods ranged from 0.56 mm to 1.35 mm. A smartphone with a depth sensor was found to be the most appropriate acquisition method. Originality/value A novel and scalable mass customisation design process was presented, which can automatically generate CAD models of custom-fit respirator masks in a few minutes from a raw 3D facial mesh. Four acquisition methods, including the use of a statistical shape model, a smartphone with a depth sensor, a light stage and a structured light scanner were compared; one method was recommended for use in a pandemic crisis considering equipment cost, acquisition time and geometric accuracy.

scholarly journals A Concept Design of an Adaptive Tendon Driven Mechanism for Active Soft Hand Orthosis

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 21
Author(s):  
Bruno Lourenço ◽  
Vitorino Neto ◽  
Rafhael de Andrade
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Vital Role ◽  
Dorsal Side ◽  
Concept Design ◽  
Cord Injury ◽  
3D Printed ◽  
Biomechanical Constraints ◽  
Active Orthosis

The Hands exert a vital role in the simplest to most complex daily tasks. Losing the ability to make hand movements, which is usually caused by spinal cord injury or stroke, dramatically impacts the quality of life. In order to counteract this problem, several assisting devices have been proposed, but they still present several usage limitations. The marketable orthoses are generally either the static type or over-expensive active orthosis that cannot perform the same degrees of freedom (DoF) that a hand can do. This paper presents a conceptual design of a tendon-driven mechanism for hand’s active orthosis. This study is a part of an effort to develop an effective and low-cost hand’s orthosis for people with hand paralysis. The tendon design proposed was thought to comply with some requisitions such as lightness and low volume, as well as fit with the biomechanical constraints of the hand joints to enable a comfortable use. The mechanism employs small cursors on the phalanges to allow the tendons to run on the dorsal side and by both sides of the fingers, allowing 2 DoF for each finger, and one extra tendon enlarges the hands’ adduction nuances. With this configuration, it is simple enough to execute the flexion and extension movements, which are the most used movements in daily actives, using one single DC actuator for one DoF to reduce manufacturing costs, or with more DC actuators to enable more natural hand coordination. This system of actuation is suitable to create soft exoskeletons for hands easily embedded into 3D printed parts, which could be merged over statics thermoplastic orthosis. The final orthosis design allows dexterous finger movements and force to grasp objects and perform tasks comfortably.

scholarly journals Kraken: A wirelessly controlled octopus-like hybrid robot utilizing stepper motors and fishing line artificial muscle for grasping underwater

2021 ◽  
Author(s):  
Yara Almubarak ◽  
Michelle Schmutz ◽  
Miguel Perez ◽  
Shrey Shah ◽  
Yonas Tadesse
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Arm Movement ◽  
Artificial Muscle ◽  
Aquatic Life ◽  
Stepper Motors ◽  
3D Printed ◽  
Arm Motion ◽  
Hybrid Actuation ◽  
Underwater Exploration

Abstract Underwater exploration or inspection requires suitable robotic systems capable of maneuvering, manipulating objects, and operating untethered in complex environmental conditions. Traditional robots have been used to perform many tasks underwater. However, they have limited degrees of freedom, manipulation capabilities, portability, and have disruptive interactions with aquatic life. Research in soft robotics seeks to incorporate ideas of the natural flexibility and agility of aquatic species into man-made technologies to improve the current capabilities of robots using biomimetics. In this paper, we present a novel design, fabrication, and testing results of an underwater robot known as Kraken that has tentacles to mimic the arm movement of an octopus. To control the arm motion, Kraken utilizes a hybrid actuation technology consisting of stepper motors and twisted and a coiled fishing line polymer muscle (TCP FL ). TCPs are becoming one of the promising actuation technologies due to their high actuation stroke, high force, light weight, and low cost. We have studied different arm stiffness configurations of the tentacles tailored to operate in different modalities (curling, twisting, and bending), to control the shape of the tentacles and grasp irregular objects delicately. Kraken uses an onboard battery, a wireless programmable joystick, a buoyancy system for depth control, all housed in a three-layer 3D printed dome-like structure. Here, we present Kraken fully functioning underwater in an Olympic-size swimming pool using its servo actuated tentacles and other test results on the TCP FL actuated tentacles in a laboratory setting. This is the first time that an embedded TCP FL actuator within elastomer has been proposed for the tentacles of an octopus-like robot along with the performance of the structures. Further, as a case study, we showed the functionality of the robot in grasping objects underwater for field robotics applications.

Design and Analysis of a New Mechanism for a Snake Like Robot

2020 ◽  
Author(s):  
Johnathon Garcia ◽  
Kooktae Lee
Keyword(s):  
Power Loss ◽  
Robot Design ◽  
The Novel ◽  
Loss Minimization ◽  
Positive Power ◽  
Unit Distance ◽  
Novel Structure ◽  
3D Printed ◽  
Numerical Minimization ◽  
Novel Design

Abstract In this paper, a novel snake like robot design is presented and analyzed. The structure described desires to obtain a robot that is most like a snake found in nature. This is achieved with the combination of both rigid and soft link structures by implementing a 3D printed rigid link and a soft cast silicone skin. The proposed structure serves to have a few mechanical improvements while maintaining the positives of previous designs. The implementation of the silicone skin presents the opportunity to use synthetic scales and directional friction. The design modifications of this novel design are analyzed on the fronts of the kinematics and minimizing power loss. Minimization of power loss is done through a numerical minimization of three separate parameters with the smallest positive power loss being used. This results in the minimal power loss per unit distance. This research found that the novel structure presented can be effectively described and modeled, such that they could be applied to a constructed model.

Numerical Towing Model for LNG Carrier Approach in Exposed Environment Calibrated With Full-Scale Measurements and Operability Criterion

2021 ◽  
Author(s):  
Erwan Auburtin ◽  
Quentin Delivré ◽  
Jason McConochie ◽  
Jim Brown ◽  
Yuriy Drobyshevski
Keyword(s):  
Numerical Model ◽  
Degrees Of Freedom ◽  
Line Tension ◽  
Full Scale ◽  
Model Parameters ◽  
Wave Loads ◽  
Simplified Approach ◽  
Large Matrix ◽  
Multi Body ◽  
The Impact

Abstract The Prelude Floating Liquefied Natural Gas (FLNG) platform is designed to offload liquefied natural and petroleum gas products to carrier vessels moored in a Side-by-Side (SBS) configuration. Prior to the mooring operation, the carrier vessel is escorted and held alongside the FLNG with the assistance of tugs connected to her bow and stern to ensure sufficient control over the vessel in this critical phase. In order to better understand the impact of environmental conditions, to determine the optimum length, strength, material and configuration of the towline stretcher, and to estimate the maximum operable environments, coupled multi-body simulations have been performed in time domain. The numerical model, which considered both the LNG carrier and the forward tug, was calibrated using full-scale measurements of tug motions and tow line tension recorded during a real approach and berthing manoeuvre at Prelude FLNG. The measured environment effects were generated numerically and the model parameters were adjusted to reproduce the recorded behavior as accurately as possible. Since actions of the tug master are difficult to model numerically and only the statistical environment parameters are known, a simplified approach has been adopted for modelling the tug propulsion and steering using a combination of static forces, stiffness and linear and quadratic damping for relevant horizontal degrees of freedom. The calibrated numerical model was first subjected to several sensitivity assessments of the modelling level (single- or multi-body, inclusion of second-order wave loads, inclusion of forward speed). Then sensitivity studies were performed to help address operational requirements related to the wave height and direction, and the stretcher length and strength. The conclusions have been taken into consideration for the selection of the tow line configurations for future operations. Finally, the calibrated coupled LNG carrier and tug model was used to derive Prelude-specific tug operability criteria that may be used for decision-making based on weather forecasts, prior to the SBS offloading operations. A large matrix of swell and wind driven waves was simulated over a range of wave heights, periods, directions and static towing forces to allow a criterion to be developed based on a stochastic extreme tow line tension. Such criterion considers relevant wave parameters while remaining simplified enough for easy use in operations. This paper describes the assumptions and process to numerically model the towing configuration and calibrate the different coefficients, discusses the results obtained for the various sensitivities, and explains the operability criteria. Important conclusions and lessons learnt are also shared.

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