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Hoi! -- A Multimodal Dataset for Force-Grounded, Cross-View Articulated Manipulation

Engelbracht, Tim, Zurbrügg, René, Wohlrapp, Matteo, Büchner, Martin, Valada, Abhinav, Pollefeys, Marc, Blum, Hermann, Bauer, Zuria

arXiv.org Artificial Intelligence

W e present a dataset for force-grounded, cross-view articulated manipulation that couples what is seen with what is done and what is felt during real human interaction. The dataset contains 3048 sequences across 381 articulated objects in 38 environments. Each object is operated under four embodiments - (i) human hand, (ii) human hand with a wrist-mounted camera, (iii) handheld UMI gripper, and (iv) a custom Hoi! gripper - where the tool embodiment provide synchronized end-effector forces and tactile sensing. Our dataset offers a holistic view of interaction understanding from video, enabling researchers to evaluate how well methods transfer between human and robotic viewpoints, but also investigate underexplored modalities such as force sensing and prediction.


Head Stabilization for Wheeled Bipedal Robots via Force-Estimation-Based Admittance Control

Wang, Tianyu, Yan, Chunxiang, Liao, Xuanhong, Zhang, Tao, Wang, Ping, Wen, Cong, Liu, Dingchuan, Yu, Haowen, Lyu, Ximin

arXiv.org Artificial Intelligence

Abstract-- Wheeled bipedal robots are emerging as flexible platforms for field exploration. However, head instability induced by uneven terrain can degrade the accuracy of onboard sensors (e.g., cameras) or damage fragile payloads. Existing research primarily focuses on stabilizing the mobile platform but overlooks active stabilization of the head in the world frame, resulting in vertical oscillations that undermine overall stability. T o address this challenge, we developed a model-based ground force estimation method for our 6-degree-of-freedom (6-DOF) wheeled bipedal robot. Leveraging these force estimates, we implemented an admittance control algorithm to enhance terrain adaptability. I. INTRODUCTION As robotics technology advances, wheeled bipedal robots are being increasingly deployed for agile exploration [1].


TransForSeg: A Multitask Stereo ViT for Joint Stereo Segmentation and 3D Force Estimation in Catheterization

Fekri, Pedram, Zadeh, Mehrdad, Dargahi, Javad

arXiv.org Artificial Intelligence

--Recently, the emergence of multitask deep learning models has enhanced catheterization procedures by providing tactile and visual perception data through an end-to-end architecture. This information is derived from a segmentation and force estimation head, which localizes the catheter in X-ray images and estimates the applied pressure based on its deflection within the image. These stereo vision architectures incorporate a CNN-based encoder-decoder that captures the dependencies between X-ray images from two viewpoints, enabling simultaneous 3D force estimation and stereo segmentation of the catheter . With these tasks in mind, this work approaches the problem from a new perspective. We propose a novel encoder-decoder Vision Transformer model that processes two input X-ray images as separate sequences. Given sequences of X-ray patches from two perspectives, the transformer captures long-range dependencies without the need to gradually expand the receptive field for either image. The embeddings generated by both the encoder and decoder are fed into two shared segmentation heads, while a regression head employs the fused information from the decoder for 3D force estimation. The proposed model is a stereo Vision Transformer capable of simultaneously segmenting the catheter from two angles while estimating the generated forces at its tip in 3D. This model has undergone extensive experiments on synthetic X-ray images with various noise levels and has been compared against state-of-the-art pure segmentation models, vision-based catheter force estimation methods, and a multitask catheter segmentation and force estimation approach. It outperforms existing models, setting a new state-of-the-art in both catheter segmentation and force estimation. A catheter is a flexible, intravascular tube used in cardiac catheterization to access and navigate the cardiovascular system with precision.


Estimation of Aerodynamics Forces in Dynamic Morphing Wing Flight

Gupta, Bibek, Kim, Mintae, Park, Albert, Sihite, Eric, Sreenath, Koushil, Ramezani, Alireza

arXiv.org Artificial Intelligence

Accurate estimation of aerodynamic forces is essential for advancing the control, modeling, and design of flapping-wing aerial robots with dynamic morphing capabilities. In this paper, we investigate two distinct methodologies for force estimation on Aerobat, a bio-inspired flapping-wing platform designed to emulate the inertial and aerodynamic behaviors observed in bat flight. Our goal is to quantify aerodynamic force contributions during tethered flight, a crucial step toward closed-loop flight control. The first method is a physics-based observer derived from Hamiltonian mechanics that leverages the concept of conjugate momentum to infer external aerodynamic forces acting on the robot. This observer builds on the system's reduced-order dynamic model and utilizes real-time sensor data to estimate forces without requiring training data. The second method employs a neural network-based regression model, specifically a multi-layer perceptron (MLP), to learn a mapping from joint kinematics, flapping frequency, and environmental parameters to aerodynamic force outputs. We evaluate both estimators using a 6-axis load cell in a high-frequency data acquisition setup that enables fine-grained force measurements during periodic wingbeats. The conjugate momentum observer and the regression model demonstrate strong agreement across three force components (Fx, Fy, Fz).


How can AI reduce wrist injuries in the workplace?

Pitzalis, Roberto F., Cartocci, Nicholas, Di Natali, Christian, Caldwell, Darwin G., Berselli, Giovanni, Ortiz, Jesús

arXiv.org Artificial Intelligence

This paper explores the development of a control and sensor strategy for an industrial wearable wrist exoskeleton by classifying and predicting workers' actions. The study evaluates the correlation between exerted force and effort intensity, along with sensor strategy optimization, for designing purposes. Using data from six healthy subjects in a manufacturing plant, this paper presents EMG-based models for wrist motion classification and force prediction. Wrist motion recognition is achieved through a pattern recognition algorithm developed with surface EMG data from an 8-channel EMG sensor (Myo Armband); while a force regression model uses wrist and hand force measurements from a commercial handheld dynamometer (Vernier GoDirect Hand Dynamometer). This control strategy forms the foundation for a streamlined exoskeleton architecture designed for industrial applications, focusing on simplicity, reduced costs, and minimal sensor use while ensuring reliable and effective assistance.


GeoDEx: A Unified Geometric Framework for Tactile Dexterous and Extrinsic Manipulation under Force Uncertainty

Chen, Sirui, Marinovic, Sergio Aguilera, Iba, Soshi, Zarrin, Rana Soltani

arXiv.org Artificial Intelligence

--Sense of touch that allows robots to detect contact and measure interaction forces enables them to perform challenging tasks such as grasping fragile objects or using tools. T actile sensors in theory can equip the robots with such capabilities. However, accuracy of the measured forces is not on a par with those of the force sensors due to the potential calibration challenges and noise. This has limited the values these sensors can offer in manipulation applications that require force control. In this paper, we introduce GeoDEx, a unified estimation, planning, and control framework using geometric primitives such as plane, cone and ellipsoid, which enables dexterous as well as extrinsic manipulation in the presence of uncertain force readings. Through various experimental results, we show that while relying on direct inaccurate and noisy force readings from tactile sensors results in unstable or failed manipulation, our method enables successful grasping and extrinsic manipulation of different objects. Additionally, compared to directly running optimization using SOCP (Second Order Cone Programming), planning and force estimation using our framework achieves a 14x speed-up. Dexterous manipulation capabilities are essential for robots to function effectively in human-centered environments, such as helping with tasks that involve handling different objects or tools [1]. Planning and control methods for such tasks that can enable robust and generalizable contact-rich manipulation need contact force information. While force sensors can provide accurate force readings, physical limitations associated with embedding the sensors into the robotic hands, as well as lack of high-resolution tactile information limit the use of these sensors. On the other hand, recent developments in tactile sensors resulted in ever lighter and higher resolution sensors, which can be installed on different robot end-effectors such as fingertips of a dexterous hand. However, it is still quite challenging and expensive to develop tactile sensors that can provide accurate force readings, especially in both normal and shearing directions. While developing such tactile sensors is important, the ongoing research efforts in the field of dexterous manipulation require relying on the available tactile sensors with the aforementioned shortcomings. Previous works have shown that even using binary [2] or highly discretized [3] information from tactile sensors can already significantly improve performance during in-hand object reorientation.


MagicGel: A Novel Visual-Based Tactile Sensor Design with MagneticGel

Shan, Jianhua, Zhao, Jie, Liu, Jiangduo, Wang, Xiangbo, Xia, Ziwei, Xu, Guangyuan, Fang, Bin

arXiv.org Artificial Intelligence

Abstract-- F orce estimation is the core indicator for evaluating the performance of tactile sensors, and it is also the key technical path to achieve precise force feedback mechanisms. This study proposes a design method for a visual tactile sensor (VBTS) that integrates a magnetic perception mechanism, and develops a new tactile sensor called MagicGel. The sensor uses strong magnetic particles as markers and captures magnetic field changes in real time through Hall sensors. On this basis, MagicGel achieves the coordinated optimization of multimodal perception capabilities: it not only has fast response characteristics, but also can perceive non-contact status information of home electronic products. I. INTRODUCTION With the rapid advancement of tactile sensor technology, its crucial role in robotics, automation systems, and human-computer interaction has become increasingly evident. Tactile sensors enhance a robot's ability to perceive its environment, equipping the robot with more precise and intelligent operational capabilities. In the field of flexible operation and human-computer interaction, accurate tactile perception is the key to realizing core functions such as bionic grasping and force-controlled interaction. Traditional tactile sensors are mostly based on piezoresistance, capacitance or piezoelectric principles, which can achieve quantitative force perception. However, they have significant limitations in spatial resolution, dynamic response range and force estimation accuracy. J Shan and J Zhao are co-first authors of the article.


ForcePose: A Deep Learning Approach for Force Calculation Based on Action Recognition Using MediaPipe Pose Estimation Combined with Object Detection

M, Nandakishor, Govind, Vrinda V, Puthalath, Anuradha, L, Anzy, S, Swathi P, R, Aswathi, R, Devaprabha A, Raj, Varsha, K, Midhuna Krishnan, T, Akhila Anilkumar V, P, Yamuna V

arXiv.org Artificial Intelligence

Force estimation in human-object interactions is crucial for various fields like ergonomics, physical therapy, and sports science. Traditional methods depend on specialized equipment such as force plates and sensors, which makes accurate assessments both expensive and restricted to laboratory settings. In this paper, we introduce ForcePose, a novel deep learning framework that estimates applied forces by combining human pose estimation with object detection. Our approach leverages MediaPipe for skeletal tracking and SSD MobileNet for object recognition to create a unified representation of human-object interaction. We've developed a specialized neural network that processes both spatial and temporal features to predict force magnitude and direction without needing any physical sensors. After training on our dataset of 850 annotated videos with corresponding force measurements, our model achieves a mean absolute error of 5.83 N in force magnitude and 7.4 degrees in force direction. When compared to existing computer vision approaches, our method performs 27.5% better while still offering real-time performance on standard computing hardware. ForcePose opens up new possibilities for force analysis in diverse real-world scenarios where traditional measurement tools are impractical or intrusive. This paper discusses our methodology, the dataset creation process, evaluation metrics, and potential applications across rehabilitation, ergonomics assessment, and athletic performance analysis.


Sensorless Remote Center of Motion Misalignment Estimation

Yang, Hao, Al-Zogbi, Lidia, Yildiz, Ahmet, Simaan, Nabil, Wu, Jie Ying

arXiv.org Artificial Intelligence

Laparoscopic surgery constrains instrument motion around a fixed pivot point at the incision into a patient to minimize tissue trauma. Surgical robots achieve this through either hardware to software-based remote center of motion (RCM) constraints. However, accurate RCM alignment is difficult due to manual trocar placement, patient motion, and tissue deformation. Misalignment between the robot's RCM point and the patient incision site can cause unsafe forces at the incision site. This paper presents a sensorless force estimation-based framework for dynamically assessing and optimizing RCM misalignment in robotic surgery. Our experiments demonstrate that misalignment exceeding 20 mm can generate large enough forces to potentially damage tissue, emphasizing the need for precise RCM positioning. For misalignment $D\geq $ 20 mm, our optimization algorithm estimates the RCM offset with an absolute error within 5 mm. Accurate RCM misalignment estimation is a step toward automated RCM misalignment compensation, enhancing safety and reducing tissue damage in robotic-assisted laparoscopic surgery.


Image-to-Force Estimation for Soft Tissue Interaction in Robotic-Assisted Surgery Using Structured Light

Wang, Jiayin, Yao, Mingfeng, Wei, Yanran, Guo, Xiaoyu, Zheng, Ayong, Zhao, Weidong

arXiv.org Artificial Intelligence

For Minimally Invasive Surgical (MIS) robots, accurate haptic interaction force feedback is essential for ensuring the safety of interacting with soft tissue. However, most existing MIS robotic systems cannot facilitate direct measurement of the interaction force with hardware sensors due to space limitations. This letter introduces an effective vision-based scheme that utilizes a One-Shot structured light projection with a designed pattern on soft tissue coupled with haptic information processing through a trained image-to-force neural network. The images captured from the endoscopic stereo camera are analyzed to reconstruct high-resolution 3D point clouds for soft tissue deformation. Based on this, a modified PointNet-based force estimation method is proposed, which excels in representing the complex mechanical properties of soft tissue. Numerical force interaction experiments are conducted on three silicon materials with different stiffness. The results validate the effectiveness of the proposed scheme.