bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Dynamics Simulation of the Contact Force in Planar Mechanism With Clearance
Authors: Yousuf Louay S.
Published: November 2023

A planar mechanism with three moving parts is connected to a cam. The mechanism is consisted from crank arm, connecting rod, flat-faced follower, polydyne cam, and two guides with clearance. The investigation of the dynamic simulation of the contact force between the cam and the follower is considered in the presence of crank arm and connecting rod mechanism. Nonlinear response of the contact force is simulated at different guide width of the follower guide and at different cam speeds. SolidWorks program is used in the calculation of contact force at different cam speeds and different guide’s width. The nonlinear dynamics simulation of the planar mechanism is described using Lyapunov exponent parameter, Poincare’ map, Fast Fourier Transform, and phase-plane mapping. Local Lyapunov exponent is calculated using the MatLab code of the dynamic tool algorithm based on the values of time delay and embedding dimensions. The amplitude of Fast Fourier Transform is determined using the analysis of power spectrum while phaseplane diagram is drawn using the relation between the contact force and its variation.
Investigating the Effect of a Brand Factor in Product Design Based on a Data-Driven Approach Using Online Reviews
Authors: Park Seyoung , Kim Harrison
Published: November 2023

Recently, online user-generated data has emerged as a valuable source for consumer product research. However, most studies have neglected the brand effect, although it is a significant factor in conventional market research. This paper demonstrates the importance of brands in data-driven design using online reviews. Specifically, the study utilizes game theory and suggests a game setting representing market competition. Elements of the game are determined based on online data analysis. The proposed approach consists of three stages. The first stage divides online customers into different segments and analyzes them to extract the feature importance of each brand in each segment. The importance is based on the term frequency of each feature, and it becomes the customer’s partial utility for each feature. The second stage defines the specification of product candidates and calculates their costs. This study refers to real market datasets (Bill of Materials) available online. At this point, the game is all set. The final stage finds the Nash Equilibrium of the designed game and compares the optimal strategy for a product portfolio with and without brand consideration. The suggested approach was tested on smartphone reviews from Amazon. The result shows that the lack of brand consideration leads a company to choose a non-optimal product strategy, illustrating the significance of the brand factor.
A Variable-Stiffness Link for Safe Robot Interactions
Authors: Nelson Carl A. , Swerczek Nick , Tannehill Amber
Published: November 2023

This paper presents a new variable-stiffness link design for safe robot interactions. By integrating a linear spring using the variable-lever principle, the link system replicates the linear rotational stiffness behavior typical of a variable-stiffness joint (or variable-stiffness actuator) while avoiding the size constraints that tend to make the latter difficult to design and build. A nonlinear relationship between lever arm and rotational stiffness gives the system a large range of stiffness variation. Implementation of a prototype validated the theoretical model, and simulation of a two-link variable-stiffness planar robot illustrated the practical utility of the proposed design.
Optimal Control of Spine and Shoulder Powered Exoskeletons for Squat Lifting
Authors: Arefeen Asif , Xiang Yujiang
Published: November 2023

In this study, a two-dimensional (2D) human skeletal model is used to predict the optimal lifting motion for the cases with and without exoskeletons using inverse dynamics optimization. The kinematics and dynamics of the human model were expressed in Denavit-Hartenberg (DH) representation. Furthermore, the electromechanical dynamics of the spine and shoulder exoskeletons’ DC motors are modeled in the lifting optimization formulation. The design variables are human joint angle profiles and exoskeleton motor current profiles. The normalized human joint torque squared is minimized subject to physical and lifting task constraints. The optimization problem was solved by the gradient-based optimizer SNOPT. The comparison of the predicted human joint angle profiles, joint torque profiles, and ground reaction force (GRF) profiles are presented between lifting tasks with and without exoskeleton assistance. The optimal torques of the exoskeletons at the spine and shoulder joints are achieved by solving the lifting optimization problem, and it is observed that the proposed method has reduced the human joint torque magnitudes due to the exoskeletons’ assistance. The peak values of the human spine and shoulder joint torque magnitudes decreased by 6.40% and 38.01% respectively, due to the exoskeleton assistance. However, human knee joint torque has slightly increased due to the extra weight of the exoskeletons.
Amplitude-Voltage Response of Parametric Resonance of Electrostatically Actuated Circular Membranes
Authors: Alipi Marcos , Caruntu Dumitru I.
Published: November 2023

This paper deals with the amplitude-voltage response of parametric resonance of electrostatically actuated MEMS circular membranes resonator for sensing applications. The system consists of a flexible circular membrane over a parallel ground plate. A soft AC voltage is applied between the MEMS membrane and ground plate to actuate the membrane near its first natural frequency. Two methods of investigation are used in this research, namely the method of multiple scales (MMS), and the reduced order model (ROM). These methods were used to solve for the voltage response of the MEMS analytically and numerically. This work also reports the effects the damping and frequency parameters have on the voltage response. It is shown that increasing the damping parameter decreases the size of the escape band and decreases the nonlinear effect on the system. Increasing the detuning frequency decreases the size of the escape band, shifts the bifurcation points to lower voltages, and the steady-state amplitudes of the system decrease.
Spatial Elements and Their Influence on Creative Work: A Systematic Literature Review
Authors: Mejía-Londoño Valentina , Rendon-Velez Elizabeth
Published: November 2023

Creative spaces have been the subject of study in recent years. Multiple research studies have demonstrated the positive impact that an accurate workspace design has on increasing worker productivity and well-being. However, there are still many questions about the influence of workspace design on creativity and creative work. This paper aims to provide a review of the state-of-the-art about spatial elements (e.g., tables, chairs, whiteboards, etc.) that influence creative work which is carried out in creative spaces such as offices or learning environments. We conducted a literature search within the Scopus database, and we screened and filtered the returned 2214 sources based on their title and abstract. After that, we identified 34 relevant articles, with which we carry a full-text analysis. From selected articles, we extracted: (i) spatial elements present in creative environments and (ii) how these elements influence creative work. We found that most of the spatial elements provide visual stimuli and inspiration, allow people to build things and capture spontaneous ideas easily, and contribute to the flexible use of the space, encouraging collaboration, privacy, or social encounters. The results provide an overview of the current state of the art of creative spaces topic that can be used by researchers, practitioners, and educators to conduct further research in this field and to take better decisions about spatial element choice.
Influence of Fixed Ring Gear Structural Compliance on the Quasi-Static and Dynamic Response of Epicyclic Gear Sets
Authors: Ryali Lokaditya , Talbot David
Published: November 2023

The structural compliance of annular ring gear can significantly influence the quasi-static and dynamic performance of an epicyclic gear set. As powertrain components are continually being optimized to their design limits, this influence becomes prominent and can no longer be ignored. The current paper will study the impact of ring gear compliance on the dynamic response of epicyclic gear sets, in fixed ring gear configuration. To achieve this objective the current study will incorporate a finite element (FE) based ring gear formulation into the three-dimensional planetary load distribution model of Ryali and Talbot [1]. The updated model is used to conduct parametric studies involving different planetary gear designs, ring gear fixtures (bolted vs. splined), and operating conditions (quasistatic, dynamic). In the case of a splined ring gear fixture, an external splined tooth contact model is developed, which will be used to validate the model against the quasi-static experiments of Ligata et al. [2]. The discussed results demonstrate the fidelity of the developed model, thus making it an excellent tool for the design and analysis of planetary gears with thin annular ring gears.
Kinematics of an Adjustable Cam-Linkage Mechanism for a Variable Displacement Hydraulic Motor
Authors: Pozo-Palacios Jonatan , Voth John A. F. , Van de Ven James Donald
Published: November 2023

Displacement adjustment is a key method for controlling hydraulic circuits in practical applications that use pumps and motors. However, the currently available low-speed high-torque (LSHT) motor designs do not provide continuous variable displacement capability. For this reason, this research work introduces a novel kinematic formulation of an adjustable cam-linkage mechanism, which is used to design a variable displacement linkage motor (VDLM). This paper presents a general description of the cam-linkage mechanism formulated with a system of kinematic equations. Next, the process to calculate the linkage limits of motion for different displacements is described, followed by the procedure to adjust the linkage mechanism. Subsequently, the synthesis process of the cam-linkage mechanism applied in a variable displacement hydraulic motor is presented. A physical prototype is designed and built using the selected mechanism and is used for validation purposes. Finally, the paper discusses the model development results, the experimental validation of the linkage mechanism, and draws conclusions. The experimental results show that the linkage kinematics model is accurate, with only minor differences found in experimental piston trajectories which are thoroughly analyzed. The models and concepts presented here have the potential to be used for the design and synthesis of adjustable cam-linkage mechanisms with various topologies.
A Visual Representation of Engineering Catalogs Using Variational Autoencoders
Authors: Sridhara Saketh , Suresh Krishnan
Published: November 2023

Catalogs have been used for over a century for designing engineering systems. While catalogs are excellent repositories of engineering information, they are difficult to navigate, specifically to spot clusters, gaps, substitutes, and outliers. Inspired by Ashby charts for material selection, we propose here, a visual representation of engineering catalogs using neural networks. In particular, we employ variational autoencoders (VAEs) to project catalog data onto a lower-dimensional latent space. The latent space can then be visualized to explore the underlying structure of the catalog. Specifically, creators can use this visual representation to identify gaps and outliers in their data, while end users can benefit from this representation to compare catalogs from competitors, and to find substitutes. Contours can be super-imposed on the charts to enable selection based on user-defined attributes; these contours are generalization of design indices associated with Ashby charts. Various examples of catalogs across engineering disciplines, ranging from materials and bearings to motors and batteries are illustrated using the proposed method. Using these examples, we (1) study the impact of the latent space dimension on the representational error, (2) illustrate how designers can easily choose alternate configurations based on their design requirements, and (3) gaps in catalog offerings can be clearly identified, providing a stimulus for new product development.
A Force- and Stress-Deflection Model of Serpentine Flexures for Use in a Compliant Bone Plate
Authors: Huxman Connor , Butler Jared
Published: November 2023

Serpentine flexures offer several advantages for use in linear motion mechanisms, including distributed compliance to reduce stress and increase range of motion and manufacturability. In this work, we develop a model for predicting the moment, vertical deflection, and maximum stress experienced in both uniform and extended serpentine flexures in response to an input vertical force. Finite element validation demonstrates the model’s ability to capture these three metrics across several flexure topologies with a mean error of 0.86%, while maintaining fixed-guided boundary conditions for flexures with any number of horizontal segments. Finally, the model’s utility is demonstrated in the design of a novel single-piece compliant fracture fixation plate that leverages serpentine flexures to deliver controlled axial motion for long bone healing. Model-derived stress-equivalent flexures are compared in their transverse and torsional rigidity. The proposed model and specific findings can be leveraged to design linear motion mechanisms that incorporate serpentine flexures across a wide range of applications.
Identifying a Relationship Between Design Concept Representation Style and Consumer Product Preference
Authors: Echerd Jonathan , Sylcott Brian , Lemken Russell , Weckesser Gerald , Lee Jinkun
Published: November 2023

Product designers are constantly seeking insight into the mind of the consumer in efforts to get a better idea as to what the market demands. Feedback from consumers informs designers on changes that need to be made to a product and can provide information about what end-users expect. To explore possible improvements to the design process, a study was conducted on concept representation style and its effects on consumer preferences. The study employed statistical testing to identify a relationship between representation style and consumer preference consistency, lending insight into the best practices for conveying critical information throughout the design process. The study described consists of conducting a series of surveys, introducing hand drawings, solid models, and realistic renderings as representations of eyeglass frames to participants, eliciting preference data from those participants, and comparing their preference ratings to those of physical models of the same frames. This study was supplemented with an eye-tracking system to establish a connection of where the effective details lie in the design representations, as well as suggest some decision-making strategies at play. Results indicate that a significant difference in consistency between representation styles does exist, and that CAD solid models are inconsistent with preferences of physical models. When only participants with an engineering background were evaluated however, this relationship did not exist, suggesting that a familiarity with a particular design practice may impact how individuals judge a particular representation style. It is also suggested by eye-tracking analysis that participants were more likely to give semantic responses when observing physical models.
Design of Reprogrammable, Rotary, Single-Actuator Mechanical Logic Valves for Fluid Diversion
Authors: Bessette Jonathan T. , Burcat Steven , Slocum Alexander H.
Published: November 2023

Fluid systems often require complex and plentiful valving which route a variety of input and output streams according to a system state. Many valves and actuators can create additional points of failure, maintenance, and cost. Multi-port selector valves are one solution which simplify complex configurations but are designed for a specific application. This custom design can create inflexibility and increased manufacturing cost when the user wishes to consider architectural changes or alternative applications. Modular, reconfigurable systems exist in fluid power systems (hydraulics, pneumatics), but few exist for larger, bulk flow applications. To address the issue of reconfigurability and simplicity within complex fluid valve architectures, we consider how one would design a single-actuator, reprogrammable, mechanical logic valve. We consider design requirements for such a system, various strategies and concepts, and converge on exploring the design of a multiport, rotary valve. Geometric layout and performance models are proposed and parametrically analyzed to understand the design space, trends, and tradeoffs. This work lays initial foundation and exploration of modular, mechanically reconfigurable, rotary valves. We envision this design and architectural toolbox to be metaphorically similar to common, easy-to-assemble and reconfigure, standardized materials such as 80/20, push-to-connect fittings, and even Legos - but instead, with application to valve geometries.
Robust Topology Optimization of Synchronous Reluctance Motors Using Cardinal Basis Function Based Level Set Method
Authors: Tian Jiawei , Torrey David , Luo Fang , Longtin Jon , Chen Shikui
Published: November 2023

Synchronous reluctance motors (SynRMs) have gained considerable attention in the field of electric vehicles as they reduce the need for permanent magnets in the rotor, resulting in less material and manufacturing costs. However, their lower average torque and torque ripple vibrations have been identified as key issues that require resolution. In this study, we present a SynRM design framework employing the cardinal basis functions (CBF)-based parametric level set method. The SynRms design problem is recast as a variational problem constrained by Maxwell’s equations which describe the behavior of electric and magnetic fields in the SynRM. A continuum shape sensitivity analysis is carried out using the material derivative and adjoint method. A distance regularization energy function is employed to maintain the level set function as a signed distance function during the optimization. The parametric topology optimization problem is computationally solved using the Method of Moving Asymptotes (MMA). To demonstrate the effectiveness of our approach, we present a numerical example that compares the torque characteristics of the optimal design with those of a reference design. Preliminary results show that the optimized SynRM has a 30.30% increase in average torque, along with a slight increase in torque ripple, compared to the reference model.
Analytically Determined Frequency Shifts for a Continuous Model 3D Printed Metal Beam With Square Void Defect
Authors: Howell Quin I. , Davis Joshua I. , Folden Trevor , Lamon Stewart , O’Connor Dennis M.
Published: November 2023

Metal 3D printing techniques are now at the forefront of the additive manufacturing industry. These innovative methods permit the use of new and novel methods of fabrication that allow for more intricacy, resolution, and detail than possible with traditional methods. However, despite the advancements in research of crack and defect propagation of conventional manufacturing methods, less attention has been paid to the dynamic attributes of metal 3D printed parts. This study investigates the vibration phenomenon of an additively manufactured, metal, cantilever, beam with an intentionally placed square void using analytical and finite element methods. By considering a segmented continuous beam, the frequency response of higher modes are analytically determined and compared to non-void responses. Relative frequency shifts were realized to indicate the presence of internal defects. Furthermore, this approach is validated using finite element methods (FEM).
Co-Design in the Himalaya: Embracing Local Knowledge and User Innovation to Address Household Energy Challenges
Authors: Richmond Robyn C. , Sweeney Daniel J. , Frey Daniel D. , Baliga Sucheta
Published: November 2023

Around the world, 2.4 billion people use biomass fuels, coal, and kerosene for cooking and heating, and in 2020, 3.2 million deaths worldwide were linked to household air pollution (HAP) from unsafe use of these fuels [1]. Many organizations have been working to address the complex challenges related to traditional cooking and space heating practices in low-resource communities; however, these challenges remain pervasive, and are exacerbated in regions like the Himalaya due to a lack of access to improved technologies and additional barriers experienced by high-elevation communities. Increased engagement of users has shown to result in higher quality solutions that better meet user needs [2, 3]. Practicing participatory design is increasing in stove development, but few examples demonstrate the engagement of users as peers in the design process.

The authors traveled to five villages in the Himalayan region, engaging community members in the design process in order to better understand cooking practices and user priorities. This paper describes the process of co-designing with a traditional stove user in a rural Himalayan community in India. As a result of this process, a deeper understanding of complex patterns of stove usage and preferences was gained. In addition, the user’s participation in the process resulted in a higher quality design that reduced HAP while preserving important features of the traditional stove. This case study contributes to growing research on and practice of participatory design to improve outcomes in household energy initiatives in low-resource communities.
Calculation of Partial Transmission Ratios of Two-Stage Gearboxes by Volume Minimization
Authors: Abraham Tom , Fuentes-Aznar Alfonso
Published: November 2023

A primary design parameter of gearboxes is the transmission ratio. A transmission ratio dictates the ratio of input to output speed and, when it is great enough, is commonly split into several partial transmission ratios via multiple gear stages. The method of splitting up a total transmission ratio is often left to best judgment. This study presents an optimization algorithm for selecting the partial transmission ratios of two-stage non-reverted spur/helical gearboxes. The optimization is accomplished by minimizing the volume of the gears within the transmission while ensuring that each gear maintains a minimum bending and contact safety factor. Results of the optimization performed over a range of total transmission ratios showed a strongly linear model that will allow powertrain designers to quickly select partial transmission ratios by only considering the total transmission ratio. It was additionally shown that, despite the many parameters involved in gearbox design, the most significant factor in this optimization model is the total transmission ratio.
Torque Characteristics of a Planetary Gear Train During Gear Shifting Under Two Inputs and One Output Tandem Driving Conditions
Authors: Shimura Daiki , Hirogaki Toshiki , Aoyama Eiichi , Nakagawa Masao , Yuba Shinnosuke
Published: November 2023

Planetary gear trains (PGTs) are widely used in many machines and are one of the most important mechanisms in hybrid vehicles. In recent years, the automotive industry has been undergoing a once-in-a-century transformation and the shift from gasoline-powered vehicles to electric vehicles (EVs) is accelerating. To respond to the shift to EVs, the possibility of a tandem drive system for EVs consisting of two input motors, and a PGT is attracted attention to achieve it as one of suitable solutions. However, it is necessary to clarify the torque characteristics of the output shaft of the PGT during the gear shifting phase to take advantage of the feature of changing the drive state based on the driving condition. In this study, we proposed a method to elucidate the torque characteristics of a PGT during gear shifting using a block diagram designed from the equations of motion of each element under tandem driving conditions. By comparing the torque fluctuation of a PGT measured in a drive experiment during gear shifting with the results of a simulation using the block diagram, we discussed the effect of the moment of inertia on the torque fluctuation. The results indicate that by reducing the moment of inertia of the ring gear shaft, the maximum amplitude of the torque fluctuation could be reduced, while the convergence time of the torque fluctuation does not change significantly.
A Hybrid Continuation Framework for Analyzing Nonlinear Normal Modes of Piecewise-Linear Systems
Authors: Huang Shih-Chun , Tien Meng-Hsuan
Published: November 2023

The prediction of the modal properties of non-smooth mechanical systems with clearances and prestress presents a computational challenge, since the nonlinearity induced by piecewise-linear stiffness eliminates the use of efficient linear modal analysis techniques. For obtaining nonlinear normal modes (NNMs) of structural systems through modal analysis, a numerical framework that combines numerical integration, the shooting method, and the arc-length continuation scheme is the most widely used approach. This numerical continuation framework computes NNMs through iterative numerical calculations; thus, the computational cost of nonlinear modal analysis of complex nonlinear systems, or non-smooth systems in particular, becomes prohibitively expensive as the model size increases. In this work, a new hybrid continuation framework combining analytic and numerical methods is proposed to efficiently compute the NNMs of non-smooth systems. This new hybrid framework uses a semi-analytic method to conduct the iterative shooting procedure; thus, the computational burden of the numerical continuation can be significantly reduced. The proposed method is demonstrated on a spring-mass oscillator with contact elements, and the NNMs obtained using the new method are validated by those computed using the traditional numerical continuation framework. The modal properties of the system can be computed using the proposed framework with significant computational savings.
A Novel Ultrasonic Fully Reversible Bending Fatigue Test Specimen for Simulated Gear Tooth Bending Fatigue
Authors: Cameron Zachary A. , Tallerico Thomas
Published: November 2023

Gears in vertical lift applications will typically experience greater than 107 bending fatigue cycles over their design lifetime. Currently, fatigue life prediction of gears exceeding 107 cycles are based on empirical correlations, since collection of fatigue data beyond 107 cycles is impractical with traditional fatigue testing methods. Ultrasonic fatigue testing enables fatigue testing in excess of 109 cycles in as few as 14 hours. In this paper, a novel specimen design for ultrasonic fatigue testing to accurately represent the geometry, stress profile, and residual stress of gear teeth in reversible bending fatigue is presented. The specimen design is discussed in detail, testing is performed to validate operating principles, and an initial fatigue data set of 8 specimens is presented.
Consideration of Autonomous Decentralized Coordination of Electric Balancer and Robotic Arm With Inertia Compensation for Larger Payload Manipulation
Authors: Hanai Hiroaki , Ozawa Mikio , Hirogaki Toshiki , Aoyama Eiichi
Published: November 2023

This study proposes an autonomous decentralized coordination of a robotic arm with an electric balancer to achieve larger payload manipulation. The characteristic feature of this research is that the robotic arm performs only position control, while the electric balancer performs only weight compensation in a decentralized manner. The electric balancer is a device that assists a person’s gravity-directional transfer operation. It detects the weight of the object to be transported and generates a torque that balances the weight. Accordingly, the person performs the conveyance manipulation. When a person manipulates the electric balancer, the person learns the characteristics of the balancer to achieve the manipulation. In this study, this is presented using a learning curve. However, the robotic arm manipulates the balancer according to position control; therefore, control interference may occur. Previous studies have focused on viscosity and friction in impedance control of electric balancers. The electric balancer used in this research can modify the magnitude of inertia compensation. Consequently, the influence of the inertia compensation on the coordination assist provided to the robotic arm is discussed.
Design and Control of a Bio-Inspired Inchworm Robot Using a Novel Helical Artificial Muscle Actuator
Authors: Quarnstrom Joel , Xiang Yujiang
Published: November 2023

Bio-inspired robots provide solutions in many applications. Robots that can traverse and transport materials through confined areas are useful in disaster response, mining, mapping, and tunneling. The proposed robot is an inchworm-inspired robot that contracts and expands its body segments to move. It has spiky feet that are angled to only allow each foot to slide forward. It has a small frontal area compared to its length, and this allows it to travel through tight gaps or tunnels. Each segment uses two helical actuators as prismatic linkages to drive both forward movement and turning movement. These helical actuators transform the rotation of stepper motors into linear motion. Many linkage configurations were considered in designing this robot, and one without continuous singularities was selected. The robot stride consists of an extension phase and a contraction phase. In each phase, one foot is stationary, and one foot is moving. When each of the feet is in motion, the ground reaction force is assumed to be zero. The motion planning of the robot is designed so that the velocity and acceleration of each of the robot’s rigid bodies is zero at the beginning and end of each movement phase. In the future, this robot will be prototyped using mostly 3D printed components, and its control algorithm will be refined during testing.
Nonlinear Vibration Absorber for Reducing Hand Vibration From a Vibro-Impact Hammer Model
Authors: Alabi Oreoluwa , Gupta Sunit Kumar , Barry Oumar
Published: November 2023

The transmission of vibrations from hand-held impact machines (HHIM) to the human hands is undesirable and can cause serious injury, including amputation of the hand. Therefore, it is crucial to analyze and develop efficient vibration control methods to curb vibration transmission to the hands from a HHIM. The first step towards developing an efficient vibration control method is to obtain a model that can accurately predict the dynamics of the HHIM. Thereafter, a numerical or theoretical study of the HHIM-Vibration control device model can reveal the devices effectiveness. To address the need for a HHIM model, we analyze a reduced order model of a HHIM which incorporates the vibro-impact interactions of the HHIM bit with the ground. The effectiveness of a cubic nonlinear absorber in the HHIM is then studied via a lumped mass parameter model consisting of a vibro-impact tool model coupled to the hand-arm system (HAS) and a cubic nonlinear tuned vibration absorber (NLTVA). A detailed numerical analysis of this system is performed to show the rich nonlinear dynamics of the system. The results from this study show that an appropriate selection of absorber parameters can effectively change the amplitude and periodicity of vibrations at the hand, thereby proving the potential of a cubic nonlinear absorber as a viable vibration control option.
Workspace Determination of Kinematic Redundant Manipulators Using a Ray-Based Method
Authors: Ginnante Angelica , Caro Stéphane , Simetti Enrico , Leborne François
Published: November 2023

Determining the workspace of a robotic manipulator is extremely significant for knowing its abilities and planning the robot application. There exist several techniques for the robot workspace determination. However, these methods usually are affected by computational redundancy, like in the case of Monte Carlo based methods, or their implementation is difficult. Moreover, the workspace analysis of kinematic redundant manipulators is even more complex. This paper introduces a ray-based workspace determination algorithm, easy to implement and not affected by computational redundancy. The proposed method can be applied to any type of serial robot, but it is tested only on spatial kinematic redundant robots. The results show how the approach can clearly determine the boundary of the robot workspace in a short period of time. Finally the time and quality performance of the ray-based method results are compared to the Monte Carlo one demonstrating the improvement of the proposed method.
Reaction Force Analysis and Validation of a Rigid Origami-Inspired Modified Wren Parallel Mechanism With Flexure Hinges
Authors: Jiang Zhujin , Zhang Ketao
Published: November 2023

Adopting a screw algebra-based approach, this paper analyzes the stiffness of flexure hinges and the resultant reaction force (RRF) of a rigid origami-inspired modified Wren parallel mechanism with flexure hinges (WPM) capable of helical motion. Analytical solution of the RRF, consisting of force in the direction of translation and torque around the axis of helical motion, applied to the platform of the WPM by flexure hinges is revealed. Simulation is implemented to verify the theoretical analysis of the RRF of the WPM. To further validate the theoretical model, multi-layered aluminium composite panel is selected for fabricating flexure hinges and the WPM capable of high precise motion and large force transmission. The resistive torque of the flexure hinge and the RRF of the WPM are measured and compared with the analytical solution. Both simulation and experimental results reveal that the RRF of the WPM resulted from flexure hinges is precisely modelled using the screw algebra-based approach. A novel bipedal robot integrating the WPM is developed for applications in extreme environment where pneumatically actuated systems are preferred over electrical machines and drives. This study paves a way for developing novel WPM-integrated robotic devices and precisely modelling the coherent stiffness of the rigid origami-inspired parallel mechanisms with flexure hinges.
Comparisons of Dynamic Models of a Stacked Miura-Origami Structure Based on Different Modeling Techniques
Authors: Wu Haiping , Liu Zuolin , Fang Hongbin
Published: November 2023

Origami-inspired structures and materials have shown great potential in engineering fields, but encounter some dynamic issues. Conventional research on folding sequence, kinematics, and static analysis is not sufficient to effectively predict the dynamic behavior of origami structures, therefore, an accurate and processible dynamic model is necessary. This paper discusses the effects of different modeling techniques on the static/dynamic behavior of origami structures. Stacked Miura-origami is selected as the research platform to study the effects of different modeling techniques on the static and dynamic characteristics of origami structures. Quasi-static tests and dynamic experiments are first carried out to provide data for modeling purposes. The force-displacement constitution relationships and dynamic responses under harmonic excitation are then studied and compared. It indicates that under low external excitation energy, the response amplitude is closely related to the tangent stiffness at the steady-state equilibrium position, which is related to the accuracy of the constitution curves. Nevertheless, the proposed models show different dynamic behaviors when the excitation frequency is increased, in some circumstances, the response even exceeds the kinematic limits. A complete parameter study is necessary to advance the state of the art of dynamic modeling for origami structures based on different techniques in the future. This paper presents a fundamental understanding of the dynamic modeling of origami structures, and the results are beneficial to provide a guide for establishing an accurate and processible dynamic model.
Building a Cloud-Based Digital Twin for a Robotic Assembly System
Authors: Bin Touhid Md Tahmid , Marne Mrunal , Oskroba Theodore , Mirahmadi Sayed Amirhossein , Zhu Enshen , Mahrabian Alireza , Defersha Fantahun , Yang Sheng
Published: November 2023

The potential of Digital Twin (DT) technology to revolutionize industry by enabling virtual simulations of physical systems in real-time has garnered significant attention in recent years. DTs have been widely applied in the manufacturing field to solve various problems, such as shopfloor resource optimization, layout design, commissioning, monitoring, and supervisory control. However, current DT research works are highly conceptual, and how to develop a DT for a legacy system needs more practical understanding. To address the challenge, this paper develops a cloud-based pipeline for building a digital twin of a robotic assembly system. The proposed pipeline is featured by cloud infrastructures, real-time bi-directional monitoring and control, and web-based DT. The use of cloud infrastructure and WebGL helps to increase remote accessibility, enabling real-time visualization of the DT through web environments. To demonstrate the viability of the proposed pipeline, a proof-of-concept DT of a robotic assembly system with over 2000 components was implemented with demonstrated scenes of online order submission, job status monitoring, exception handling, and remote feedback control. Overall, the proposed cloud-based DT pipeline could provide a practical and efficient solution for integrating DT technology into real-world cyber-physical systems. Future works and limitations are also discussed in the end.
A Novel Pre-Rotating Rotary Guardrail and its Effects on Guiding and Anti-Collision
Authors: Haoyang Su , Kaiqiang Mi , Xiaohui Su , Jiantao Zhang
Published: November 2023

In this paper, a novel pre-rotating guardrail is proposed to enhance the guiding and anti-collision capability of guardrail as the car hits in road accident. The new design sets up pre-rotating through leaf spring installed inside the rotary. The function of the proposed pre-rotating design is numerically studied by using LS-DYNA tool. The preliminary results are reported in the paper.
Safe Robot to Human Tool Handover to Support Effective Collaboration
Authors: Kang Jeon Ho , Limcaoco Paolo , Dhanaraj Neel , Gupta Satyandra K.
Published: November 2023

Robot-to-human mechanical tool handover is a common task in a human-robot collaborative assembly where humans are performing complex, high-value tasks and robots are performing supporting tasks. This paper discusses an approach to ensure the safe handover of mechanical tools to humans. We introduce a framework to enable smart robotic assistants to safely and efficiently perform robot-to-human tool handovers. Our system utilizes a specialized gripper design capable of firmly grasping objects with irregular geometries. We utilize a tool end detection method so that the robot grasps the tool end and ensures that the human can safely grab the handle during handover. Additionally, the system is able to detect if the tool moves during the grasping process and either restart the pickup or account for the new orientation during hand-off planning. Lastly, the hand-off planning ensures the robot releases the tool at the appropriate time when the human has safely grabbed the handle. Our experimental results indicate that our system can safely and effectively hand off many different types of tools. We have tested the system’s ability to handle contingencies that may occur during the handover process successfully.
Large-Scale Path Planning in Complex Environments Based on Genetic Algorithm
Authors: Hu Chuanhui , Jin Yan
Published: November 2023

Path planning has been a hot research topic in robotics, and it is also a vital functionality for autonomous systems. Generating optimal-quality path plans with the least computing time has always been the goal of researchers. As the time complexity of traditional path planning algorithms grows rapidly with the scale and complexity of the problem, evolutionary algorithms are widely applied due to their capability of giving near-optimal solutions to complex problems. However, evolutionary algorithms can be easily trapped in a local optimum and may converge to infeasible solutions. As the scale of the problem increases, evolutionary algorithms usually cannot find a feasible solution with random exploration, which makes it extremely challenging to solve long-range path-planning problems with these algorithms in environments filled with obstacles. This paper introduces a novel area-based collision assessment method for Genetic Algorithm (GA) that can guide the algorithm to find solutions with a variable number of waypoints in large-scale and obstacle-filled environments. To avoid premature convergence, the mutation process is replaced by a self-improving process to let the algorithm focus the operations on any potential solutions before discarding them in the selection process. The case studies show that the proposed GA-focus algorithm can be applied to different types of large-scale and challenging environments, escape local optimums, and find high-quality solutions.
A Comprehensive Dynamic Continuous Impact Model With Plastic Deformation
Authors: Mozaffari Hamed , Dabiri Arman
Published: November 2023

This paper presents a new comprehensive dynamic continuous impact model that accounts for elastic, elastoplastic, and plastic deformations. The model establishes the necessary conditions for each elastic, elastoplastic, and plastic deformation, considering the contact geometry, material characteristics, and impact dynamics. The proposed dynamic continuous impact model addresses the shortcomings of previous models in accurately predicting hysteresis curves and accounts for both material damping and plastic deformation. The proposed impact model solution is obtained through analytical calculation by eliminating additional assumptions and simplification approximations. The multi-variable integrals are transformed into a single one To obtain the analytical solution of the energy loss calculation. The incorporated extra dynamic parameters, such as damping factor and permanent deformation, are adjusted using the coefficient of restitution, resulting in a more practical hysteresis curve. These parameters are particularly important in high-speed impacts where the energy loss of damping is significant. To validate the performance of the proposed impact model, simulations are conducted for the collision of two stainless steel balls under different deformation scenarios (elastic, elastoplastic, and plastic). Additionally, finite element analysis results for an impact between a flat drill rod and a hammer rod are utilized. The simulation outcomes confirm that the newly developed impact model provides more accurate and realistic hysteresis curves compared to traditional static and dynamic continuous impact models.
Influence of Support Posture on Working Plate Operation for Grasp-Less Handling Technology With an Industrial Dual-Arm SCARA Robot
Authors: Yamanishi Genki , Hanai Hiroaki , Mita Yuma , Hirogaki Toshiki , Aoyama Eiichi
Published: November 2023

In this study, a measurement method was developed in which a ball rolling motion is created in a circular orbit on the work plate by horizontal in-plane maneuvering motion of the plate, named graspless ball handling, and the rolling motion error with respect to the reference circle is utilized. An experiment was conducted on a teaching method for controlling the rolling motion of the ball at a position away from the center of the robot on the work plate. It was found that an error occurs in the peripheral speed in the rotation of the plate. When the work plate is grasped and the movement is taught, the program using the master-slave method was the primary influence on the motion error, confirming the possibility of correction.
A Design Automation Framework Supporting Design for Additive Manufacturing
Authors: Wiberg Anton , Persson Johan A. , Ölvander Johan
Published: November 2023

This scientific paper introduces a Design Automation (DA) framework that streamlines the Design for Additive Manufacturing (DfAM) process. The framework is designed to simplify the creation and evaluation of different design options by automating geometry creation using high-level CAD templates and setting up and connecting Computer-Aided Engineering (CAE) models to perform functional and manufacturing evaluations. By considering manufacturing constraints early in the design process, the framework aims to investigate various design alternatives and facilitate design changes late in the development process without additional manual work.

This framework provides a comprehensive view of the entire DfAM process, integrating everything from functional requirements to manufacturing evaluation and preparation into the same design automation framework. To demonstrate the usefulness of the framework, the authors used it to design a hydraulic pump. Compared to the original design, the design created with the proposed framework reduces pressure drop by more than 50% and reduces the pump’s weight by 35%. Furthermore, on an assembly level, the framework consolidates four components into two and eliminates two sealings.

In summary, the Design Automation framework introduced in this paper simplifies the DfAM process by enabling automation of geometry creation and the setup and connection of CAE models. The framework facilitates the exploration of different design alternatives early in the process, considering manufacturing constraints, and enables design changes later in the development process without manual work. The benefits of the framework are illustrated through the design of a hydraulic pump, where it achieved significant improvements in performance, weight, and assembly complexity.
Combined Estimation of Vehicle Body State and Sprung Mass Based on Electronically Controlled Air Suspension System
Authors: Xu Wanqiu , Yu Liangyao , Li Yong , Cheng Yiming
Published: November 2023

Aiming at vehicles equipped with the electronically controlled air suspension system, precise body status signals are needed as control inputs during ride comfort and stability control. However, there is an error between the signals measured by height sensors in the system and the actual body height changes due to the sensor installation and measurement principle. Therefore, a combined estimation method based on the Kalman filter and recursive least squares is proposed to solve the above problem, and the vehicle body state and sprung mass are estimated simultaneously. In this paper, a seven-degree-of-freedom dynamics model of the air suspension system is established. Based on this model, a Kalman filter estimator is established to estimate the state of the body, and the recursive least squares method is introduced to estimate the sprung mass of the vehicle to reduce the deviation in the state estimation. Finally, a simulation platform is built and the effectiveness of the proposed method is verified under the condition of the double lane change. The results show that the variation of sprung mass will deteriorate the state estimation results of the Kalman filter estimator, and the combined estimator of the Kalman filter and recursive least squares can effectively improve the accuracy of body state estimation.