Assembly Operations Research Articles

Visual Localization Method for Fastener-Nut Disassembly and Assembly Robot Based on Improved Canny and HOG-SED

Visual positioning accuracy is crucial for ensuring the successful execution of nut disassembly and assembly tasks by a fastener-nut disassembly and assembly robot. However, disturbances such as on-site lighting changes, abnormal surface conditions of nuts, and complex backgrounds formed by ballast in complex railway environments can lead to poor visual positioning accuracy of the fastener nuts, thereby affecting the success rate of the robot’s continuous disassembly and assembly operations. Additionally, the existing method of detecting fasteners first and then positioning nuts has poor applicability in the field. A direct positioning algorithm for spiral rail spikes that combines an improved Canny algorithm with shape feature similarity determination is proposed in response to these issues. Firstly, CLAHE enhances the image, reducing the impact of varying lighting conditions in outdoor work environments on image details. Then, to address the difficulties in extracting the edges of rail spikes caused by abnormal conditions such as water stains, rust, and oil stains on the nuts themselves, the Canny algorithm is improved through three stages, filtering optimization, gradient boosting, and adaptive thresholding, to reduce the impact of edge loss on subsequent rail spike positioning results. Finally, considering the issue of false fitting due to background interference, such as ballast in gradient Hough transformations, the differences in texture and shape features between the rail spike and interference areas are analyzed. The HOG is used to describe the shape features of the area to be screened, and the similarity between the screened area and the standard rail spike template features is compared based on the standard Euclidean distance to determine the rail spike area. Spiral rail spikes are discriminated based on shape features, and the center coordinates of the rail spike are obtained. Experiments were conducted using images collected from the field, and the results showed that the proposed algorithm, when faced with complex environments with multiple interferences, has a correct detection rate higher than 98% and a positioning error mean of 0.9 mm. It exhibits excellent interference resistance and meets the visual positioning accuracy requirements for robot nut disassembly and assembly operations in actual working environments.

ОБЕСПЕЧЕНИЕ ЭКСПЛУАТАЦИОННЫХ ПАРАМЕТРОВ ШПИНДЕЛЕЙ МЕТАЛЛОРЕЖУЩИХ СТАНКОВ НА ЭТАПАХ РЕМОНТА И ВОССТАНОВЛЕНИЯ

The study objective is to develop a model for determining the parameters of the spindle bearing assembly of metal-cutting machines, taking into account the minimum runout of the functional surface. The task to which the paper is devoted is to develop a technique for evaluating deviations from the alignment of the functional surface of a part (spindle) relative to the axis of the base necks. Research methods: modeling the influence of shape accuracy parameters and the relative position of the spindle support necks on the radial runout of the base cone using the theory of dimensional relationships. The novelty of the work: for the first time the effect of the accuracy parameters of the mating parts on the performance of the spindle assembly is analyzed and recommendations are given to reduce the radial runout of the functional surface. Research results: a model is developed to determine the parameters of the shape error and the error of the relative position of the surfaces and their effect on the radial runout of the spindle functional surface at the stage of the bearing assembly. Conclusions: in order to achieve the specified operational parameters of the spindle assembly at the stages of restoration and repair, it is necessary to develop a technique for performing control and assembly operations, taking into account the influence of shape accuracy parameters and the accuracy of the mutual positioning of the mating surfaces of all parts of the assembly unit.

A chemical approach for probing the interphase boundary between polymer electrolyte membrane and HT-PEM fuel cell carbon nanofiber anode

Interphase boundary interactions are essential for high-temperature polymer electrolyte membrane fuel cell membrane electrode assembly (MEA) operation. Interactions between the self-phosphorylating polybenzimidazole (PBI)-6F coating on a carbon nanofiber electrode and the self-phosphorylating proton-conducting membrane during MEA operation would improve the cell performance. The presented approach represents a novel path for the development of a PBI membrane-based MEA.

Technical and Economic Analysis of a Robotic Station for Assembling the FPV Drone Body

Abstract The current technological progress is possible due to automated assembly and transport operations, and the increasing use of robotic cells. This article presents a robotic station for assembling the body of an FPV drone. The article uses analyzes and simulations as well as the results of simulation studies. The research has shown that the robotic station significantly increases the efficiency of the assembly process compared to traditional methods, shortening the unit production time by approximately 30-50%. The economic analysis has shown that despite higher initial costs, the investment in a robotic station pays off in approximately 3.3 years, which results from lower operating costs and the elimination of some labor costs. Moreover, the automation of assembly processes not only contributes to financial savings, but also to the improved quality of the final product. The future research should focus on further optimization of robotic stations, in particular on increasing their flexibility and adaptability in dynamic production environments.

Enhanced efficiency and quality in wind turbine gearbox assembly: a new parallel assembly sequence planning (PASP) model

ABSTRACT This paper presents two major advances in parallel assembly sequence planning (PASP) for complex systems, specifically wind turbine gearboxes. The proposed time-cost-quality PASP hybrid model (PASP-TCQ) aims to enhance efficiency, reduce costs, and improve quality by aligning optimisation parameters with real-world demands. This model is designed to optimise complex assembly processes by addressing constraints on time, cost, and quality effectively. Additionally, we introduce a particle swarm-bacteria foraging optimisation (PSBFO) algorithm that integrates the global search capability of particle swarm optimisation (PSO) with the local optimisation strengths of bacteria foraging optimisation (BFO). Integrating PSBFO into PASP-TCQ achieves significant improvements: a 17% reduction in assembly time to 100 hours, a 10% cost reduction to $94,500, and a quality index improvement to 0.93. Statistical tests, including analysis of variance (ANOVA) and tukey’s honest significant difference (HSD), confirmed the PSBFO’s superiority, with significant gains of 8.44 units over BFO and 13.02 units over PSO in objective function values (p < 0.05). Extensive simulations on a 10 MW wind turbine gearbox validate the effectiveness of the PASP-TCQ and PSBFO, demonstrating their potential to enhance efficiency and productivity in industrial assembly operations.

Innovation in technology solutions for erecting large-span coatings through module lifting

Based on the conducted analysis of the characteristics of known organizational and technological options for non-crane lifting, including the preliminary assembly of structural-technological coating blocks on low scaffolding using the pulling method with hydraulic lifting modules placed on the tops of design columns, or the pushing method, where the support beams are pushed to the design height resting on the tops of growing lifting column shafts with the growing unit located on the foundations, a new technology has been developed. This technology for large-span coatings erection uses mechanized process equipment in the form of lifting modules. According to this method, the vertical movement of the bearing beams of the large-span coating, pre-assembled into a structural-technological block on the foundations, is performed by pushing within the space between paired columns of the supporting frame, resting on the tops of the growing installation columns. The growing up of installation column sections occurs by alternately resting the column sections on the hydraulic jacks of the lifting modules, located in the intercolumn space on the foundations, and on the lifting latch beams fixed on the external surfaces of the paired columns. Vertical guiding profiles are fixed on the internal surfaces of the paired columns to function as deviation limiters for the column sections during the growing process. This approach reduces the amount of high-altitude assembly work to the operations of final securing of the coating beams at the design height between the tops of the paired columns of the supporting frame. It automates all processes of growing the installation column sections and moving the bearing beams of the coating from the foundation level to the column top level, reducing the overall number of construction and assembly operations, shortening the erection timelines for large-span coatings, and ensuring the complete execution of erection work within a tightly built site, with dimensions not exceeding the planned dimensions of the large-span coating being erected.

Integrating collaborative robots in manufacturing, logistics, and agriculture: Expert perspectives on technical, safety, and human factors.

This study investigates the implementation of collaborative robots across three distinct industrial sectors: vehicle assembly, warehouse logistics, and agricultural operations. Through the SESTOSENSO project, an EU-funded initiative, we examined expert perspectives on human-robot collaboration using a mixed-methods approach. Data were collected from 31 technical experts across nine European countries through an online questionnaire combining qualitative assessments of specific use cases and quantitative measures of attitudes, trust, and safety perceptions. Expert opinions across the use cases emphasized three primary concerns: technical impacts of cobot adoption, social and ethical considerations, and safety issues in design and deployment. In vehicle assembly, experts stressed the importance of effective collaboration between cobots and exoskeletons to predict and prevent collisions. For logistics, they highlighted the need for adaptable systems capable of handling various object sizes while maintaining worker safety. In agricultural settings, experts emphasized the importance of developing inherently safe applications that can operate effectively on uneven terrain while reducing workers' physical strain. Results reveal sector-specific challenges and opportunities: vehicle assembly operations require sophisticated sensor systems for cobot-exoskeleton integration; warehouse logistics demand advanced control systems for large object handling; and agricultural applications need robust navigation systems for uneven terrain. Quantitative findings indicate generally positive attitudes toward cobots, particularly regarding societal benefits, moderate to high levels of trust in cobot capabilities and favorable safety perceptions. The study highlights three key implications: (1) the need for comprehensive safety protocols tailored to each sector's unique requirements, (2) the importance of user-friendly interfaces and intuitive programming methods for successful cobot integration, and (3) the necessity of addressing workforce transition and skill development concerns. These findings contribute to our understanding of human-robot collaboration in industrial settings and provide practical guidance for organizations implementing collaborative robotics while considering both technological advancement and human-centered design principles.

A New Approach to Characterize Superplastic Materials from Free-Forming Test and Inverse Analysis

For about 60 years, the aerospace industry has been strongly interested in superplastic forming processes to produce extremely light and complex-shaped components. Superplastic characteristics are found in lightweight metallic materials such as titanium-based, aluminum-based, and, more recently, magnesium-based alloys. Since the high ductility exhibited by superplastic materials is two orders of magnitude higher than that of conventional materials, complex-shaped components can be obtained. If made with conventional materials, they require expensive assembly operations. The behaviour of superplastic materials is summarized by a constitutive equation commonly obtained via tensile testing that subjects the tested material to a one-dimensional stress state. On the contrary, free-forming tests allows us to test the material by subjecting it to a stress state similar to that determined during a real superplastic-forming process. The aim of this work is to define the characteristic parameters of superplastic materials by free-forming tests. The behaviour of superplastic materials is commonly modelled using a power law which puts the material into a stress-to-strain-rate relationship. This law needs to identify two parameters characterizing superplastic materials: the strain rate sensitivity index and the strength coefficient. In this work, a new procedure is presented that implies the two material parameters vary with strain. It allows for a reduction in the number of constants needed to determine the material constitutive equation, thus requiring low simulation time compared to models that adopt the multiple-objective optimization based on genetic algorithms (GAs). It is more suitable to be used in the industrial field. Furthermore, the proposed procedure is compared with a conventional procedure which is also based on the inverse analysis carried out through the use of a finite element analysis. The results of the conventional procedure, based on the inverse analysis, which is conducted through the use of a finite element analysis, are used to calculate the material constants, and are compared with those coming from the procedure proposed in this work. The proposed procedure appears equally simple and gives more accurate results compared to the conventional procedure. In fact, the maximum percentage error, regarding the prediction of the forming times of a free-forming process, was reduced from 20% to 8%. The development of the proposed procedure, as well as the comparison of the results with a conventional procedure, required the development of an experimental activity. This activity consists of free-forming tests conducted at a constant pressure (the pressures employed vary from 0.2 to 0.4 MPa), at a temperature of 753 K, and on circular sheets (thickness 1.0 mm and radius 40 mm) in superplastic magnesium alloy AZ31.

Mechanical Stability of Membranes in PEMWE

This study investigates the structural mechanics of membranes in proton exchange membrane water electrolysis (PEMWE) cells, with a particular focus on mechanical stressors and the resultant membrane deformation. Membrane defects such as cracks, pinholes, and thinning can occur due to mechanical stressors. Structural mechanical simulations can predict the membrane behaviour under stress if the boundary conditions are set accurately and the material models are chosen to fit experimental data. This presentation describes such model-based investigations and is divided into three parts. It begins with a general investigation of mechanical membrane behaviour in a PEMWE cell, followed by investigations regarding two different membrane reinforcing methods. Firstly, the study examines the mechanical stress exposure of Nafion® 117 membranes within PEMWE cells, with a focus on the gap geometry between the cell frame and porous transport layers (PTL). Using a finite-element analysis, mechanical stresses and strains on the membrane during assembly and PEMWE cell operation are quantified. For this purpose, a suitable material model was implemented and parameterized based on experimental data. The results of the cell simulation demonstrate that no critical states arise with a gap size of 0.15 mm, even under differential pressure up to 10 bar. However, increasing the gap sizes to over 0.3 mm can lead to membrane buckling, resulting in membrane thinning, possibly followed by membrane failure. [1]Secondly, the potential of reinforcing the membrane with a subgasket layer outside the active area is explored. Subgaskets can be used as a reinforcing layer for the membrane and are usually glued to the membrane. This study shows that subgasket layers can stabilize the membrane at the gap interface, even under differential pressure. However, this study highlights the need for careful positioning and thickness considerations of the subgasket for optimal mechanical stabilization. Furthermore, it was found that a subgasket can prevent membrane buckling, which can occur at increased gap sizes between cell frame and PTL. [2]Lastly, the use of woven web layers within the membrane structure is assessed as a reinforcement strategy to avoid membrane defects. Our findings suggest that no failure is expected during normal operation with applied woven web reinforcement, including varied temperatures and differential pressure, unless the gap size at the edge of the electrochemically active cell area exceeds 0.1 mm. [3] In conclusion, the research indicates that the choice of gap size in cell designs is crucial for preventing mechanical failures in PEMWE membranes. Additionally, the application of a reinforcement, such as a subgasket layer or woven web, can significantly enhance membrane stability, particularly at the gap interface. However, the thickness and the positioning of the subgasket must be carefully considered for optimal results. J. Kink, M. Ise, B. Bensmann and R. Hanke-Rauschenbach, J. Electrochem. Soc.(170), 54507 (2023). J. Kink, M. Suermann, M. Ise, Boris Bensmann, P. Junker and R. Hanke-Rauschenbach, Int. J. Hydrogen Energy (2024 (submitted)). J. Kink, M. Ise, B. Bensmann, P. Junker and R. Hanke-Rauschenbach, J. Electrochem. Soc.(170), 114513 (2023). Figure 1

Investigating Safety Awareness in Assembly Operations via Mixed Reality Technology

OCCUPATIONAL APPLICATIONS We investigated the impact of using Mixed Reality (MR) technology as a training tool to help trainees identify safety risks during machine assembly tasks, by analyzing their task completion efficiency and safety risk estimation capabilities. As proof-of-concept, an interactive MR module on hydraulic gripper assembly was designed and incorporated in fluid power laboratories to be tested with mechanical engineering technology students. The developed MR environment was evaluated using accident causation models. An environment analysis revealed smooth operation and minimal challenges. Incorporating interactive MR modules into training programs allows practitioners to provide trainees with hands-on experience in a simulated environment while identifying potential safety risks. Addressing limitations, such as simulating physical feedback more accurately, will be crucial for optimizing future safety training effectiveness using MR technology.

Estimation of direction and zero errors of satellite laser terminals in low-light conditions based on machine learning.

In the assembly, launch, and on-orbit operation of satellite optical communication terminals, small deviations are difficult to avoid, which can lead to pointing errors and challenges to the establishment of optical communication links. To estimate the pointing errors of on-orbit satellite terminals, a calibration algorithm is developed based on lunar surface imagery. First, a feature extraction algorithm for low-light images is employed to process consecutive frames of low-light images to obtain a lunar surface feature map. Then, by combining the feature map and error estimation model, predictions of direction errors and zero errors were achieved. The ground validation results demonstrate the effectiveness and feasibility of the proposed on-orbit error estimation algorithm under low-signal-to-noise-ratio conditions.

Detection of Piston Ring Deficiency in The Assembly of Automotive Ball Joint and Tie Rod End Parts

In today's intensely competitive environment, businesses strive to optimize production efficiency to reduce costs, increase profitability, and ensure customer satisfaction. This focus on efficiency and quality enables businesses to operate more effectively, gain a competitive advantage in the market, and move towards sustainable growth. This study uses image processing techniques to detect missing segments in the assembly of ball joints automatically. In the automotive industry, performing quality control of critical components before assembly and detecting and classifying the defective ones is essential. Many quality control methods can be applied with existing technologies. This paper proposes an automatic real-time control based on image processing techniques to detect ball joint missing segments, a common defect in the automotive industry. In the company, operators perform defect detection by visual inspection. In this system, production continues in cases where the operator cannot detect the defect. This system aims to detect the errors made by the operator during the assembly operations and provide instant feedback. The developed system uses OpenCV library algorithms that are highly accurate in detecting defects in manual assembly processes so that missing components are removed from the production chain, and production quality is significantly improved. Accuracy is over 94% when identifying missing segments, about 30% better than traditional methods. In tests, 1200 ball joints were run through the system, resulting in 1150 defects being correctly identified and removed from the production line. Accuracy is high thanks to the application of various image processing techniques such as grayscale conversion, edge detection, and shape recognition. This also provides real-time feedback to the operator so the system can reduce detection and response time from 15 seconds to 5 seconds. This increases production speed and reduces the error rate in manual assembly processes by 20%. This paper also highlights the potential of image processing technology in manufacturing. It will contribute to improved quality control mechanisms to increase the reliability and efficiency of production lines in the automotive industry.

Exploring the influence of music on cognitive performance in female assembly line workers at a medical device manufacturing unit.

The significance of enhancing working conditions for the physical health and performance of workers, particularly female workers, underscores the need for research in this domain and the examination of interventions such as music. Previous studies have yielded diverse outcomes regarding the influence of music on individuals' performance; hence, further research in this area appears imperative. The aim of this study is to explore the impact of music on the cognitive and task performance of female assembly operation operators. This study is an interventional (quasi-experimental) study that involved 81 participants from the female workforce of the medical equipment assembly unit in Isfahan, Iran. The evaluation encompassed task performance, working memory using N-Back test, sustained attention using continues performance test (CPT), degree of sleepiness, and mental fatigue using Flicker Fusion test, along with physiological parameters such as heart rate and blood oxygen level. Participants underwent testing both in the presence of classical music and in a condition without music playback. The provision of background music enhanced the workers' sustained attention and working memory. It led to improved task performance and a reduction in drowsiness. Concerning physiological parameters, it resulted in a slight decrease in heart rate at the end of the work shift and a marginal increase in participants' blood oxygen levels. Background music enhanced working memory (p-value = 0.001), sustained attention (p-value = 0.001), and improved the task performance of workers(p-value = 0.005). Additionally, likely due to increased relaxation, it led to a decrease in heart rate (p-value = 0.001) and an increase in blood oxygen levels (p-value = 0.016). Music also played a role in reducing participants' sleepiness (p-value = 0.001).

Graduation-inspired manufacturing system and synchronization mechanism for hybrid assembly cell lines

This paper presents an innovative flexible assembly system – hybrid assembly cell lines (HACL) to adapt to small batch, high product variety and dynamic demands. HACL provides specially designed trolleys for assembly operations, materials and tools to form the workstations flexibly and quickly at low reconfiguration cost. To conduct accurate and effective control for this complex assembly system, this paper presents a modified Graduation-inspired Manufacturing System (GMS), a recently proposed new card-based control system. GMS for HACL designs three kinds of tickets and the ticketing mechanism to absorb the uncertainties of HACL. Job tickets are for workload control and synchronization of part deliveries; setup tickets are for cell line formation and synchronization of resources of tools and machines; operation tickets are for production execution and synchronization of workers and operations in cell lines. GMS for HACL develops Internet of Things-enabled (IoT-enabled) architecture for managing the smart tickets to achieve automatic and intelligent interoperability between GMS and the physical workstations of HACL. This work designs synchronization mechanism based on specific model and genetic algorithm to synchronize manufacturing resources under GMS for HACL.

Usulan Perbaikan Proses Produksi Pada CV. Kandayas Furniture dengan Pendekatan Model Simulasi Sistem

Kandayas Furniture is one of the companies engaged in manufacturing tables. The table production process goes through several stages. Based on field observations and interviews that have been conducted, problems arise from the company's production process. The problem exists in the assembly process because many products are waiting, so there is a buildup in the assembly process of the table. The buildup occurs because the assembly process to the finished material warehouse has a considerable distance difference. This resulted in an ineffective production process. Then, in Promodel Now the movement of each work station still uses human labor which results in delays in the production process. From this problem, it is obtained that the process flow changes are more structured, the material handling distance from assembly to finished goods is shorter because there are changes in the lay out that we propose and make material handling time more efficient, using handlift conveyance in each flow, adding assembly operators due to bottlenecks in assembly due to the paint drying process, using a paint oven machine for drying paint to shorten the time and reduce the accumulation of goods, and implementing K3 according to the SOP so that employees avoid work accidents. Keywords: Bottleneck; Productivity; ProModel Software; System Simulation

Impact of bolt positioning on the stiffness of angular support brackets

Bolts and screws are usually preferred over other joining techniques when assembly and disassembly operations are required. However, they add extra weight to the system, so it is essential to reduce their size and weight by optimizing bolt parameters. Additionally, the stiffness of bolted members is very crucial; those with low stiffness may affect the correct functioning of the other connected components. This study focuses on the impact produced by bolt positions, specifically their center of gravity and spacing among them, on the stiffness of angular L-shaped brackets using Finite Element Analysis. Bending and torsional loads were applied to the free end of the member and deformations were recorded under these loads. The results revealed that a triangular bolt pattern is recommended for three bolts, whereas for four or more bolts, the pattern should be uniform to avoid stress concentrations. Moreover, the center of gravity and bolt spacing have a significant impact on stiffness. By optimizing bolt spacing and the center of gravity, a combination of six bolts can be replaced with four bolts of the same size while maintaining the same stiffness.

АНАЛІЗ ВПЛИВУ ІНДИВІДУАЛЬНИХ ХАРАКТЕРИСТИК КОМІРОК LiFePO4 НА ПАРАМЕТРИ РОБОТИ АКУМУЛЯТОРНИХ ЗБІРОК

The article analyzes the influence of the individual characteristics of lithium-iron-phosphate (LiFePO4) cells on the overall efficiency, stability and duration of operation of battery assemblies. The influence of such parameters as internal resistance, polarization resistance and capacity on the operation of battery assemblies under different load regimes and changes in temperature conditions was studied. It was found that these parameters can vary significantly between cells within the same assembly, which leads to an imbalance during the operation of the battery system. Such an imbalance causes an uneven distribution of charge between the cells, which reduces the overall performance of the system, accelerates the degradation of the cells and shortens their service life. To overcome these problems, the use of active balancing methods based on Unscented Kalman Filter (UKF) algorithms was proposed. The application of UKF allows for dynamic evaluation of the state of charge (SOC) of each cell and adjustment of system parameters in real time, which provides more accurate management of battery assemblies in conditions of variable external factors such as temperature and current loads. Special attention is paid to online identification of battery parameters, such as polarization resistance and capacity, which change over time due to cell aging. The conducted studies confirmed that constant monitoring of temperature regimes is critically important for maintaining stable operation of battery cells, preventing overheating and ensuring uniform load distribution. The performed simulation confirmed the effectiveness of the application of adaptive methods of balancing and temperature control, which allows to increase the reliability and overall performance of battery assemblies.

Camera Calibration in High-Speed Robotic Assembly Operations

The increase in positioning accuracy and repeatability allowed the integration of robots in assembly operations using guidance systems (structured applications) or video acquisition systems (unstructured applications). This paper proposes a procedure to determine the measuring plane using a 3D laser camera. To validate the procedure, the camera coordinates and orientation will be verified using robot coordinates. This procedure is an essential element for camera calibration and consists of developing a mathematical model using the least square method and planar regression. The mathematical model is considered necessary as a step towards optimizing the integration of robotic vision systems in assembly applications. A better calibrated camera has the potential to provide better recognition results, which are essential in this field. These improved results can then be used to increase the accuracy and repeatability of the robot.

On Self-Positioning and Self-Fixation of Parts Made of Alloys with Shape Memory Effect under Component Assembling

Introduction Violation of mutual positioning and fixation of parts worsens the operation of the equipment. Traditional approaches to solving the problem under consideration have been sufficiently studied: interchangeability of parts and the use of special equipment. Both methods involve a significant number of additional elements and assembly operations. Fixation is often provided by means of force fitting and welding. Disadvantages of these methods include assembly, residual and other stresses, engineering constraints, etc. To solve these problems, alloys with thermoelastic phase transformations are used, which provide shape memory effects (SME) to manifest themselves. This article describes, for the first time, self-positioning and self-fixation using the example of parts specially made from an alloy with SME. Materials and Methods. The pin element under pressing mandrels the blind hole of the cup and enters the seat. The alloy with SME was Ti-55.7wt%Ni. The temperature of the onset of its austenitic transformation was As = 95°C ± 5°C. The elemental composition was determined by a Shimadzu EDX-8000 X-ray fluorescence spectrometer, the phase composition — by a Shimadzu XRD-7000 diffractometer. The temperature was specified through differential scanning calorimetry. The range was 20–300°C, the heating rate was 5 deg/min. A Guide T120 thermal imager and a RangeVision DIY 3D scanner with structured illumination were used. After pressing the pin into the cup at different angles, the alignment and deviations between the axes of the cup and the pin were examined. Then, the cup was heated to 110–120°C, cooled, and control measurements were taken.Results. Values of the deflection angle after pressing were 0.2–11°. With a rigid structure and an installation angle of 0°, the pin deflected in the mounting hole by 0.2–0.5°. The axes shifted and did not intersect. The pin was not always completely pressed in. This indicated uneven deformation of the metal and different stress values around the hole. Such a unit would soon fail. The pin took the required position after heating the cup to 110–120°C (this temperature was higher than at the end of the reverse martensitic transformation). The angular deviation of the axes was noted to be 0.03–0.1°. The maximum misalignment (0.04 mm) corresponded to high positioning accuracy. Heating during the reverse martensitic transformation created internal stresses that returned the initial geometry of the cup. They also formed the forces that positioned and fixed the pin in the hole. That is, it is the parts that provide positioning and fixation (this is selfpositioning and self-fixation).Discussion and Conclusion. For self-positioning and self-fixation of parts due to the shape memory effect, it is necessary to avoid sharp transition lines between the surfaces of parts during design, select rounded corners or fillets, and get a clean surface without burrs. Self-fixation and self-positioning reduce defects and inaccuracies during assembly. The use of certain alloys increases the profitability of equipment production.

Soft Robotic Honeycomb-Velcro Jamming Gripper Design

In this paper, using a honeycomb-velcro structure to generate a novel jamming gripper is explored. Each finger of the gripper consists of multi-layers with a honeycomb sandwich structure acting as a core wrapped by a fabric sheet and sealed by a latex membrane. This structure can transit between unjammed (flexible) and jammed (rigid) states thanks to the vacuum pressure. Various materials of honeycomb structure, fabric, and reinforcements are investigated to seek optimal combinations for making the jamming fingers. Then, such fingers are deployed in experiments to evaluate the stiffness and the surface friction with different loads in terms of with or without vacuum. Vacuum pressure boosts the stiffness and friction of all the jamming fingers compared with the without-vacuum case. Attached to a gripper, the jamming finger shows good performance in diverse manipulation with food, a metal component, a toy, a can, and a bottle. Furthermore, the variable-stiffness finger under vacuum pressure can be utilized to perform assembly and installation operations such as pushing a bolt into an aligned hole.