Search Results (920)

Gibson’s concept of optic flow established that perception is grounded in lawful structure generated by action. However, no formal mechanical framework has described the invariant structure of action-generated kinesthetic information during skilled manipulation. This study introduces haptic flow as a screw-theoretic invariant defined by the coupled rotational–translational organization of a body–object system. Motion capture data from a two-case comparison (one proficient and one novice golfer) were analyzed using instantaneous screw axes (ISA), pitch evolution, and cylindroid geometry derived from a linear line-complex formulation. The proficient golfer exhibited (1) progressive convergence of ISAs toward a coherent bundle, (2) stabilization of screw pitch through impact, and (3) co-cylindrical alignment of harmonic screws consistent with inertial–restoring conjugacy. In contrast, the novice golfer showed fragmented ISA organization and elevated pitch variability. These differences were descriptive rather than inferential and do not imply population-level generalization. The findings suggest that skilled manipulation is characterized by stabilization of symmetry-bearing screw invariants rather than by independent joint control. Interpreted ecologically, haptic flow is proposed as a mechanically specified candidate invariant generated by lawful body–object coupling. The present study establishes a geometric framework for quantifying such invariants while identifying the need for cross-task and perceptual validation. Full article

Current multi-axis force sensors often rely on complex mechanical structures or arrays of discrete transducers, resulting in larger footprints, higher complexity, and limited scalability for compact applications such as robotic fingertips or wearable tactile interfaces. To address these limitations, this paper introduces a novel optical sensing approach that uses a top-layer patterned color surface and an array of color sensors to decouple and measure normal, shear, and torsional forces within a highly compact 15 × 15 mm footprint. The patterned surface functions as a visual encoding layer, where applied forces induce measurable, direction-dependent shifts in reflected color distribution. By deploying multiple color sensors in an array, each sensor captures localized color variations, enabling spatial reconstruction of both magnitude and direction of applied loads through differential color analysis. The sensor’s performance was validated through robotic gripper integration, where it successfully provided multi-axis force feedback and enabled adaptive gripping force adjustment to achieve robust and stable object manipulation. The experimental results confirm the system’s ability to effectively sensing 3D forces and torsion forces, and support closed-loop control in adaptive robotic grasping. This design presents a scalable, low-profile alternative to conventional multi-axis force sensors, suitable for integration into space-constrained robotic and haptic systems. Full article

Reduced arm swing frequently occurs in older adults and is associated with declined gait performance. Experimental studies have demonstrated that restricting arm swing decreases stride length and walking speed, whereas deliberately increasing arm swing can improve these gait parameters. This study evaluated whether a wearable haptic feedback system could effectively increase arm-swing amplitude and assess its effects on spatiotemporal gait outcomes during overground walking. Using a within-subject repeated-measures design, twelve community-dwelling older adults (6 males/6 females; $75.8\pm 6.5$ years) completed three no-feedback conditions (Baseline, Exaggerated, Fast) and six feedback conditions varying Direction (Forward, Backward, Combined) and target Magnitude (+100%, +200% of the Baseline). The arm-swing angle was estimated in real time from upper-arm inertial measurement unit (IMU) sensors; targets were defined for peak Forward flexion and/or peak Backward extension, and vibrotactile cues were delivered when the corresponding peak failed to reach the target. The arm range of motion (ROM) increased significantly across conditions, with the largest increase during Feedback (+229%), exceeding Exaggerated (+120%) and Fast (+64%) (all $p<0.001$). Walking speed and stride length also increased during Feedback relative to the Baseline ($p<0.001$). Within feedback conditions, the arm ROM showed independent main effects of the Direction and Magnitude, whereas gait outcomes were primarily influenced by Direction. Arm-swing symmetry was largely preserved, with the smallest variability during Feedback. These findings support the feasibility of vibrotactile feedback to enhance arm swing and improve gait outcomes in older adults. Full article

Traditional methods to learn soft-tissue surgical procedures rely on cadaver labs or patient-based learning, which are costly and geographically limited, and raise ethical questions. Virtual reality (VR) with haptic feedback offers a scalable alternative, but most current platforms emphasize bone-based rather than soft-tissue procedures learned by feel. We developed a VR+haptic simulation for preoperative training of retropubic midurethral sling (MUS) surgery. This study examines the usability of this platform with thirteen expert urogynecologic surgeons and subsequently makes improvements (e.g., in haptics) to evaluate the platform with twelve trainees based on the NASA Task Load Index for workload and a UTAUT-informed usability survey. Objective performance scores were recorded as participants completed up to four levels of increasing realism and difficulty, starting with a transparent body and a reference surgical trajectory. Trainees reported high usability, immersion, and engagement. Experts rated the platform as valuable for sling training and skill assessment. NASA-TLX results indicated low physical and temporal demand, low mental demand and frustration, and moderate effort. These findings suggest that SurgicalEd VR is acceptable and has appropriate workload characteristics for surgical education. Future studies could examine how using VR+ haptic training improves intraoperative performance. Full article

This study examines individual-centric multimodal sensory experiences in the museum context, where multimodality is defined as the interplay among sensory modalities. Focusing on visual and haptic experiences, the research aims to investigate the role of museum lighting in shaping sensory perception at the Istanbul Museum of Painting and Sculpture. We asked how local museum visitors aged 18–26 (primarily university students and frequent museum-goers) perceive and engage with the museum atmosphere beyond visual stimuli, particularly through lighting. Data were collected through sensorywalks (n = 16), a sensory-spatial research method, and interviews (n = 10) with local museum visitors. Findings indicated that lighting enhances multimodal sensory interactions during museum visits and enhances visitors’ awareness of spatial scale, materiality, and atmosphere. The discussion highlighted the significance of sensory-based museum design, including the sensory museum models and toolkits, in rethinking how young adults engage with museum environments. Understanding the multimodal experiences offers valuable insights for advancing both research and practice in museum studies. Full article

Modern interaction with smart devices is hindered by the “Midas Touch” problem, where sensors frequently misinterpret incidental physical movements as intentional commands due to a lack of human context. This research addresses this conflict by introducing the Multimodal Haptic Informatics (MHI) index within a novel Scene–Action–Trigger (SAT) framework. The goal is to contextualize mechanical movements as human intent by integrating physical, spatial, and cognitive data locally at the edge. The methodology employs an “Action-as-primary indexing” mechanism where the Action channel (IMU) serves as a temporal anchor t, triggering high-resolution Scene (computer vision) and Trigger (audio) processing only during critical haptic events. Validated through a complex origami crane task generating 29,408 data frames, the framework utilizes a three-stage informatics derivation process: single-modal scoring, score weighting, and hand state mapping. Results demonstrate that applying an adaptive “Speedometer” logic successfully reclassifies the “Transitional State”. While this state constitutes over half of the behavioral dataset (54.76% on average), it is effectively disambiguated into meaningful intent using a self-trained local Large Language Model (LLM) for semantic verification. Furthermore, the event-driven sampling of 93 keyframes reduces the processing overhead by 99.68% compared to linear annotation. This study contributes a low-latency, privacy-preserving “Protocol of Assent” that maintains user agency by providing intelligent system suggestions based on confirmed haptic intensity. Full article

Background: Haptic virtual simulation (HVS) has emerged as a promising tool in dental education, yet evidence comparing its performance to conventional preclinical training remains limited. Establishing its effectiveness is essential to support its integration into competency-based curricula. Objective: The aim of this study was to compare Class V cavity preparations performed using conventional training on extracted teeth with those performed using a haptic virtual simulator, evaluating preparation time and cavity volume. Methods: Sixty-one extracted human molars were digitized using cone-beam computed tomography (CBCT) to generate corresponding virtual replicas. A calibrated operator prepared 122 standardized Class V cavities (61 real and 61 virtual). The simulator automatically recorded preparation time and cavity volume. For natural teeth, cavity volume was calculated by digital superimposition of pre- and post-operative STL models using Blender. Paired means were compared using Student’s t-test (α = 0.05). Results: Preparation time was significantly shorter when using HVS compared with the conventional method (p < 0.001). Virtual preparations resulted in slightly larger cavity volumes than real preparations, with a statistically significant yet clinically small difference (p = 0.047). Conclusions: Haptic virtual simulation enables more time-efficient Class V cavity preparation while producing cavity volumes comparable to those obtained through conventional training. These findings support the implementation of haptic simulators as a valid and effective complement for preclinical skill acquisition in operative dentistry. Full article

Background: Haptic virtual simulators are increasingly incorporated into dental education, yet it remains unclear whether the sequence of simulation-based and natural-tooth training influences early endodontic skill acquisition. Objective: The objective of this study was to compare the effect of two training sequences—haptic simulation followed by natural-teeth practice, versus natural-teeth practice followed by haptic simulation—on performance in endodontic access cavity preparation among undergraduate dental students. Methods: Thirty-eight third-year dental students were randomly assigned to two groups. All participants completed three consecutive attempts on a haptic simulator (Simodont^®) and one access cavity preparation on extracted mandibular incisors. Simulator metrics included progress, precision, target volume removed, and excess volume removed. Natural-tooth preparations were scored by two blinded endodontists (ICC range = 0.75–0.88). Data were analyzed using Mann–Whitney U tests with Holm correction, Wilcoxon signed-rank tests, and a linear mixed-effects model to characterize learning trajectories. Results: No significant between-group differences were found in any simulator metric (Holm-adjusted p = 0.47–0.62; effect sizes r = 0.12–0.20, 95% CI −0.14 to 0.43) or in natural-tooth performance (all Bonferroni-adjusted p = 1.00). Students demonstrated significant improvement between the first and second simulator attempts (p < 0.05), with a clear learning plateau thereafter. Mixed-effects modelling confirmed significant overall improvement across attempts (p < 0.001), with no effect of training sequence or attempt × group interaction. Conclusions: Training sequence did not influence learning outcomes or final clinical-quality access preparations. Early performance gains suggest a rapid familiarization effect, and both modalities provide complementary—but non-hierarchical—learning affordances. Haptic simulation can therefore be integrated flexibly within preclinical endodontic curricula without compromising educational effectiveness. Full article

Robotic-assisted surgery (RAS) provides enhanced dexterity and visualisation but remains constrained by the absence of clinically meaningful palpation and haptic feedback. This perspective examines palpation sensing in RAS from an engineering and system-integration standpoint, identifying the lack of tactile information as a major contributor to increased cognitive load, prolonged training, and risk of tissue injury. Recent advances in force, tactile, vibroacoustic, audio, and optical sensor technologies enable quantitative assessment of tissue mechanical properties and often exceed human tactile sensitivity. However, clinical translation is limited by challenges in sensor miniaturisation, sterilisation, robustness and integration and the absence of standardised evaluation metrics. The integration of artificial intelligence and multimodal sensor fusion with intra-operative imaging and augmented visualisation is highlighted as a key strategy to compensate for sensor limitations and biological variability. Dedicated robotic palpation devices and wireless or magnetically coupled probes are discussed as promising transitional solutions. Overall, the restoration of palpation sensing is presented as a prerequisite for improving safety and efficiency and enabling higher levels of autonomy in future RAS platforms. Full article

Reliable detection of contact states, such as the “mating” of connectors, is crucial for high-quality teleoperated assembly. Conventional systems relying solely on visual and continuous force feedback often fail to convey these discrete high-frequency transients due to the limited high-frequency rendering capabilities. This study investigates the effectiveness of augmenting visual and force feedback with vibrotactile and auditory cues for detecting connector mating. We conducted three experiments: (1) a mating detection task using recorded multimodal data ($N=10$), (2) a modality contribution analysis ($N=10$), and (3) a real-time robot connector insertion task ($N=10$). Results from the real-time task demonstrated that the proposed multimodal feedback significantly reduced the maximum contact force exerted after mating compared to the baseline visual-force condition ($p<0.001$), thereby enhancing physical safety. Furthermore, vibrotactile and auditory cues were found to be redundant yet complementary, providing robust cues even when one modality is compromised. Although subjective mental workload increased due to sensory integration, the significant improvement in detection clarity and safety justifies the multimodal approach. We conclude that providing transient vibrotactile and auditory cues is a highly effective strategy for compensating for the limitations of conventional force feedback in teleoperated assembly. Full article

Active athletes represent a specific target for learning and development. Their schedules, including training sessions and competitions, leave little time for education. However, athletes still need skills beyond sports to ensure they are prepared for future employment. Our study approaches this issue by identifying appropriate settings for athletes’ learning and development. (1) Based on the background of current athletes’ education, it addresses the gap of not enough attention being paid to transferable practices from corporate attitudes to learning and development. (2) The study’s methodology primarily uses the case study concept because this conveys the video content we created for the athletes’ learning and development. This is combined with the method of content analysis of selected examples from corporate learning and development and the design thinking workshop, with the engagement of important stakeholder groups: athletes (2 participants), lecturers (2 participants), and representatives of sports organizations (1 participant). The other 9 workshop participants were master’s students in a managerial study programme because of their age similarities with the current athletes and the applicability of the courses they were studying to athletes’ education. (3) The designed process was created as a digital twin using haptic artefacts and the S2M technology (version 1.0) within the OMiLAB platform (version 1.6). Our results show that video content tailored to the athletes’ constraints is a viable solution that improves their career prospects. (4) The study’s practical implications are supported by the expert validation of the model provided by the inside of the large sports organizations’ management. Full article

Background: The implantable miniature telescope is used to provide functional vision for patients with advanced AMD. However, despite the considerable cost of the device, there are strict criteria to be met for this procedure, since the patients require challenging neuroadaptation afterward, which sometimes fails and leads to the necessity of device explantation. Visual outcomes also depend on the stability of the microtelescope; tilts cause unwanted optical aberrations and can lead to device luxation, with sight-threatening complications. Case report: This case presents a novel technique for fixing the ophthalmic telescope device SING-IMT™. A 76-year-old female with pre-operative visual acuity of 15 letters on the ETDRS scale underwent surgery on her left eye. The superior haptic was fixed at the 12 o’clock position with a Prolene 5-0 suture, achieving good postoperative stability. The implant was stable throughout the entire observation period. Conclusions: Implant stability is crucial for maximizing visual potential in patients with advanced AMD selected for the procedure, since visual acuity in the peripheral retina, where the perceived image eventually lands, is much lower than the macula. Therefore, there is a need to standardize surgical approaches and use objective follow-up measures to assess long-term patient satisfaction. Full article

Magnetorheological (MR) fluids are composite materials composed of ferromagnetic particles, medium oils, and several types of additives. MR fluids are particularly suitable for haptic applications, because their rheological properties can be rapidly, stably, and reversibly controlled using an applied magnetic field, MR fluids are particularly suitable for haptic applications. Moreover, with recent advances in virtual reality technologies, handheld haptic interfaces that offer high portability and operability, owing to their lightweight and compact design, have become increasingly important for enhancing immersion in teleoperation systems. In this study, we design and develop a miniature MR fluid device for handheld haptic interfaces using a cylindrical rotor. The proposed device is compact and light, and exhibits a high output. We analyzed the magnetic field distribution inside the device using an analytical model and confirmed that the serpentine magnetic flux path effectively increased the magnetic flux density in the MR fluid working region. According to the experimental characterization, the device generated a maximum torque of 0.3 Nm. The resulting interface had a total mass of 122 g and provided a maximum force of 4.5 N to the user, demonstrating its suitability for teleoperation and virtual reality applications. Full article

The lack of reliable sensory input from prosthetic limbs limits transfemoral amputees’ ability to perceive limb movement without visual monitoring. This study evaluated design parameters of a proposed forearm-based vibrotactile system in a pre-clinical, design-level perceptual evaluation, conveying prosthetic joint positions through patterned vibrations to provide non-invasive proprioceptive feedback. Healthy participants completed two experiments assessing detection of tactile cues from dual-actuator bands on the wrist and elbow representing assumed ankle and knee positions. The effects of temporal structuring (sequential vs. simultaneous stimulation), actuator configuration, amplitude and frequency settings, and signal duration on response accuracy were examined. Sequential vibrations produced significantly higher recognition accuracy than simultaneous presentation (72.4% vs. 42.7%, p < 0.001) in a variety of vibration signal parameter values. Actuator placement also influenced performance: simultaneous stimulation on opposite forearm sides yielded significantly lower accuracy (p < 0.001) than same-side configurations, whereas this directional effect was not significant for sequential presentation. Accuracy did not differ significantly between equal and unequal amplitude or frequency levels across actuators. Longer stimulus durations improved accuracy, increasing from 82.3% at 60 ms to 92.5% at 240 ms, though the results indicated a saturation point, suggesting an optimal temporal window. These findings inform the design of forearm-based sensory feedback systems for improved prosthetic limb control. Full article

Background/Objectives: From birth, infants learn how to interact with the world through exploration. It has been proposed that this early learning phase is driven by motor babbling: the spontaneous generation of exploratory movements that are progressively consolidated through associative mechanisms. This process leads to the acquisition of a repertoire of hand movements such as single- or multi-finger flexion, extension, touching, and pushing. Later, in a second phase, some of these movements (e.g., those that happen to enable access to biologically salient stimuli, such as grasping food) are further reinforced and consolidated through rewards obtained from the environment. However, the neural mechanisms underlying these processes remain unclear. Here, we used a fully neuroanatomically and neurophysiologically constrained neural network model to investigate the brain correlates of these processes. Methods: The model consists of six neural maps simulating six human brain areas, including three pre-central (motor-related) and three post-central (sensory-related) regions. Each map is composed of excitatory and inhibitory spiking neurons, with biologically constrained within- and between-area connectivity forming recurrent circuits. Hand action execution and corresponding haptic perception are simulated simply as activity in primary motor and somatosensory model areas, respectively. During an initial “exploratory” phase, the network learned, via Hebbian mechanisms, associations—as emerging distributed cell assembly (CA) circuits—linking “motor” to corresponding “haptic feedback” patterns. As a result of this initial training, the model began to exhibit spontaneous ignitions of these CA circuits, an emergent phenomenon taken to represent internally generated, non-stimulus-driven attempts at hand action exploitation. In a second phase, a global reward signal, simulating dopamine-mediated reward encoding, was applied to only a subset of “successful” actions upon their noise-driven ignition. Results: During the first exploratory phase, the neural architecture autonomously developed “action-perception” circuits corresponding to multiple possible hand actions. During the subsequent exploitation phase, positively reinforced circuits increased in size and, consequently, in frequency of spontaneous ignition, when compared to non-rewarded “actions”. Conclusions: These results provide a mechanistic account, at the cortical-circuit level, of the early acquisition of hand actions, of their subsequent consolidation, and of the spontaneous transition of an agent’s behavior from exploration to reward-seeking, as typically observed in humans and animals during development. Full article