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IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

作者： Liam M. Sullivan Suzi Creveling Marissa Cowan Lukas Gabert Tommaso Lenzi Department of Mechanical Engineering and Robotics Center University of Utah Rocky Mountain Center for Occupational and Environmental Health Department of Biomedical Engineering University of Utah

Ambulation in everyday life requires walking at variable speeds, variable inclines, and variable terrains. Powered prostheses aim to provide this adaptability through control of the actuated joints. Some powered prosthesis controllers can adapt to discrete changes in speed and incline but require manual tuning to determine the control parameters, leading to poor clinical viability. Other data-driven controllers can continuously adapt to changes in speed and incline but do so by imposing the same non-amputee gait patterns for all amputee subjects, which does not consider subjective preferences and differing clinical needs of users. Here, we present a controller for powered knee and ankle prostheses that can continuously adapt to different walking speeds, inclines, and uneven terrains without enforcing a specific prosthesis position, impedance, or torque. A virtual biarticular muscle connection determines the knee flexion torque, which changes with both speed and slope. Adaptation to inclines and uneven terrains is based solely on the global shank orientation. Continuously variable damping allows for speed adaptation. Minimum-jerk programming defines the prosthesis swing trajectory at variable cadences. Experiments with one individual with an above-knee amputation suggest that the proposed controller can effectively adapt to different walking speeds, inclines, and rough terrains.

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A General Formulation for Path Constrained Time-Optimized Trajectory Planning with Environmental and Object Contacts

A General Formulation for Path Constrained Time-Optimized Tr...

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IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

作者： Dasharadhan Mahalingam Aditya Patankar Riddhiman Laha Srinivasan Lakshminarayanan Sami Haddadin Nilanjan Chakraborty Department of Mechanical Engineering Stony Brook University USA Munich Institute of Robotics and Machine Intelligence (MIRMI) Technical University of Munich

ISBN: (数字)9798350377705

ISBN: (纸本)9798350377712

A typical manipulation task consists of a manipulator equipped with a gripper to grasp and move an object with constraints on the motion of the hand-held object, which may be due to the nature of the task itself or from object-environment contacts. In this paper, we study the problem of computing joint torques and grasping forces for time-optimal motion of an object, while ensuring that the grasp is not lost and any constraints on the motion of the object, either due to dynamics, environment contact, or no-slip requirements, are also satisfied. We present a second-order cone program (SOCP) formulation of the time-optimal trajectory planning problem that considers nonlinear friction cone constraints at the hand-object and object-environment contacts. Since SOCPs are convex optimization problems that can be solved optimally in polynomial time using interior point methods, we can solve the trajectory optimization problem efficiently. We present simulation results on three examples, including a non-prehensile manipulation task, which shows the generality and effectiveness of our approach.

关键词： Uncertainty Trajectory planning Friction Simulation Dynamics Noise Polynomials Nonlinear dynamical systems Trajectory optimization Manipulator dynamics

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Design and In-Hand Analysis of a 6-Dof 3prs-Finger-Based Parallel Dexterous Hand with Bidirectional Pinching Capability

SSRN

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SSRN 2023年

作者： Zhao, Fuqun Xu, Donglai Jin, Xiaodong Ding, Xilun Guo, Sheng Xu, Kun Fang, Yuefa Department of Mechanical Engineering Beijing Jiaotong University Beijing100044 China Robotics Institute School of Mechanical Engineering and Automation Beihang University Beijing100191 China

In view of the shortcomings of the serial dexterous hand (SDH) in heavy load, precise in-hand manipulation, and bidirectional pinching capability, this paper presents a 6-DOF 3PRS-finger-based parallel dexterous hand (PDH). The PDH structure is designed, which is composed of three 3PRS parallel fingers. The pinching shape analysis is conducted to demonstrate the bidirectional pinching capability. Through the workspace analysis of the PDH pinching nine objects, the influence rule on in-hand manipulation workspace of different objects is obtained. The PDH can perform symmetrical in-hand manipulation workspace to solve the problem that almost all of humanoid dexterous hands pinch objects in a single direction. The pinching force transmission capability of the PDH is compared with that of the 3R SDH. The results show that the maximum pinching force provided by the PDH is much greater than that provided by the SDH. Bidirectional pinching experiments are carried out, which demonstrate the PDH can complete the accurate in-hand manipulation under almost frictionless conditions. The proposed PDH can provide a feasible design idea for the theoretical development and practical application of dexterous hands. © 2023, The Authors. All rights reserved.

关键词： Robotic arms

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Dynamic Neural Curiosity Enhances Learning Flexibility for Autonomous Goal Discovery

arXiv

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arXiv 2024年

作者： Houbre, Quentin Pieters, Roel Tampere University Tampere Finland Department of Automation Technology and Mechanical Engineering Cognitive Robotics Tampere University Tampere33720 Finland

The autonomous learning of new goals in robotics remains a complex issue to address. Here, we propose a model where curiosity influence learning flexibility. To do so, this paper proposes to root curiosity and attention together by taking inspiration from the Locus Coeruleus-Norepinephrine system along with various cognitive processes such as cognitive persistence and visual habituation. We apply our approach by experimenting with a simulated robotic arm on a set of objects with varying difficulty. The robot first discovers new goals via bottom-up attention through motor babbling with an inhibition of return mechanism, then engage to the learning of goals due to neural activity arising within the curiosity mechanism. The architecture is modelled with dynamic neural fields and the learning of goals such as pushing the objects in diverse directions is supported by the use of forward and inverse models implemented by multilayer perceptrons. The adoption of dynamic neural fields to model curiosity, habituation and persistence allows the robot to demonstrate various learning trajectories depending on the object. In addition, the approach exhibits interesting properties regarding the learning of similar goals as well as the continuous switch between exploration and exploitation. © 2024, CC BY-NC-SA.

关键词： Adversarial machine learning

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Dynamic disturbance substructuring: identifying localized nonlinear vibrations 30

Dynamic disturbance substructuring: identifying localized no...

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30th International Conference on Noise and Vibration engineering, ISMA 2022 and 9th International Conference on Uncertainty in Structural Dynamics, USD 2022

作者： Brøns, M. Rixen, D.J. Technical University of Denmark Department of Civil and Mechanical Engineering Nils Koppels Allé Kgs. Lyngby2800 Denmark Technical University of Munich Department of Mechanical Engineering Munich Institute for Robotics and Machine Intelligence Boltzmannstraße 15 Garching bei München85748 Germany

ISBN: (纸本)9789082893151

In this work, the novel approach Dynamic disturbance (Dydis) substructuring is introduced, and the concept is demonstrated, first on a linear system and then on a simple nonlinear system. Dydis is a means to characterize nonlinear interfaces in complex dynamic engineering structures. It can be any known slight change in the system affecting the vibrational response, as a change in stiffness, mass, inertia, or pre-loading. By measuring the vibrations of systems with and without Dydis, two sets of independent data is obtained, allowing robust estimation of interface dynamics. Nonlinear systems' natural frequencies are amplitude-dependent. Adding mass will change the frequencies and the forcing level, thus enhancing amplitude-dependent nonlinear effects. This work takes the first steps towards a nonlinear Dydis substructuring approach by applying nonlinear frequency response functions and adapting an estimation procedure to work for a simple nonlinear case. Results are promising: in a situation polluted by noise, Dydis halves the error compared to not using it. © 2022 Proceedings of ISMA 2022 - International Conference on Noise and Vibration engineering and USD 2022 - International Conference on Uncertainty in Structural Dynamics. All rights reserved.

关键词： Nonlinear systems

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Black ice danger area estimation and active speed control research by utilizing road condition sensor

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Journal of Institute of Control, robotics and Systems 2021年第11期27卷 815-823页

作者： Hwang, Daekyu Kim, Bongsang Lee, Kyuho Sim, Hongseok Moon, Heechang Industrial Convergence Interdepartmental Program Autonomous Vehicle･Intelligent Robotics The Graduate School of Hongik University Korea Republic of Mechanical & System Design Engineering Hongik University Korea Republic of

This study was performed to verify the feasibility of using a black ice danger area estimation function based on the wetness data acquired by a piezoelectric based RCS (Road Condition Sensor) through real road tests under each environment and real vehicle conditions. The techniques and system implementation are considered for the prevention of accidents caused by black ice, which primarily causes critical issues in winter every year. System detects the value of wetness on the road during (or right after) rain and snow using an RCS then can estimate the possibility of the presence of black ice on the forward path at low temperatures by combining with those obtained using the ambient temperature sensor and GIS (GPS and map). Accident avoidance and damage minimization effect is expected by securing safe driving conditions through active speed control. © ICROS 2021.

关键词： Ice

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Analysis of Effects of Sensor Error Factors on Attitude and Heading Errors for Inertial/Magnetic Sensor-based Stationary Alignment

Analysis of Effects of Sensor Error Factors on Attitude and ...

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IEEE SENSORS

作者： Chang June Lee Jung Keun Lee Department of Integrated Systems Engineering Hankyong National University Anseong South Korea School of ICT Robotics & Mechanical Engineering Hankyong National University Anseong South Korea

ISBN: (数字)9798350363517

ISBN: (纸本)9798350363524

Attitude and heading reference system (AHRS) plays an important role in a variety of application fields. In the AHRS, stationary alignment is performed to determine the initial orientation of the sensor frame with respect to the navigation frame based on inertial/magnetic sensor signals. In this study, we analyze the effects of sensor error factors of accelerometer and magnetometer on attitude and heading accuracy for stationary alignment in undisturbed conditions. This study compared the attitude and heading errors by sensor error factors including noise, bias, nonorthogonality, and misalignment. Simulation results showed that sensor noise with a constant noise density made attitude/heading errors converge to specific RMSEs regardless of sensor orientations, while nonorthogonality and misalignment caused large deviations in attitude/heading errors depending on sensor orientations.

关键词： Accelerometers Accuracy Navigation Magnetometers Simulation Noise Magnetic analysis

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Multiagent Consensus over Time-Invariant and Time-Varying Signed Digraphs via Eventual Positivity

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IEEE Transactions on Automatic Control 2023年第9期68卷 5429-5444页

作者： Fontan, Angela Wang, Lingfei Hong, Yiguang Shi, Guodong Altafini, Claudio Linköping University Division of Automatic Control Department of Electrical Engineering LinköpingSE-58183 Sweden KTH Royal Institute of Technology Division of Decision and Control Systems StockholmSE-10044 Sweden Chinese Academy of Sciences Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing100190 China University of Chinese Academy of Sciences Beijing100190 China Tongji University Department of Control Science and Engineering Shanghai201804 China University of Sydney Australian Center for Field Robotics School of Aerospace Mechanical and Mechatronic Engineering SydneyNSW2008 Australia

Laplacian dynamics on signed digraphs have a richer behavior than those on nonnegative digraphs. In particular, for the so-called 'repelling' signed Laplacians, the marginal stability property (needed to achieve consensus) is not guaranteed a priori and, even when it holds, it does not automatically lead to consensus, as these signed Laplacians may lose rank even in strongly connected digraphs. Furthermore, in the time-varying case, instability can occur even when switching in a family of systems each of which corresponds to a marginally stable signed Laplacian with the correct corank. In this article, we present novel conditions for achieving consensus on signed digraphs based on the property of eventual positivity, a Perron-Frobenius (PF) type of property for signed matrices. The conditions we develop cover both time-invariant and time-varying cases. A particularly simple sufficient condition, valid in both cases, is that the Laplacians are normal matrices. Such condition can be relaxed in several ways. For instance, in the time-invariant case it is enough that the Laplacian has this PF property on the right side, but not on the left side (i.e., on the transpose). For the time-varying case, convergence to consensus can be guaranteed by the existence of a common Lyapunov function for all the signed Laplacians. All conditions can be easily extended to bipartite consensus. © 1963-2012 IEEE.

关键词： Lyapunov functions

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A CNN-LSTM Model for IMU-based Energy Expenditure Estimation under Various Walking Conditions

A CNN-LSTM Model for IMU-based Energy Expenditure Estimation...

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International Symposium on Inertial Sensors and Systems INERTIAL

Energy expenditure (EE) is important quantities in evaluating the intensity of physical activity and health status. EE can be estimated based on signals from wearable sensors such as inertial measurement unit (IMU) and electromyography (EMG) sensor. Although many algorithms have been developed to estimate EE during daily life [1] – [4] , only a few algorithms have evaluated the performance of EE according to walking conditions (speed and incline) [2] – [4] . This paper presents a combined model of convolutional neural network (CNN) and long short-term memory (LSTM) for an IMU-based EE estimation under various walking conditions. The results of this study suggest the optimal IMU location for estimating EE during level walkings/runnings and inclined walkings.

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Experimental Investigation of Relationship between Inner Ground Resistance Force and Vibration Kinds for Underground Moving Robots

Experimental Investigation of Relationship between Inner Gro...

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Mechatronics and robotics engineering (ICMRE), International Conference on

作者： Tomohiro Watanabe Kojiro Iizuka Mechanical Engineering Program Faculty of Engineering Niigata University Niigata City Japan Department of Systems and Engineering and Science Shibaura Institute of Technology Saitama City Japan

ISBN: (数字)9798350394276

ISBN: (纸本)9798350394283

In recent years, there have been many missions where the rovers land and explore the surface of planets or other extraterrestrial bodies. The purpose of these missions is to return the samples of extraterrestrial ground. These samples can solve the planets’ origins and their sources of life. They have not only scientific value but also engineering value. Information on ground characteristics is helpful when building the base. The underground samples are especially valuable because they are not affected by space weathering and keep good conditions. In this background, the rovers, which move underground, have received attention as the method to obtain underground samples. In our previous study, the moving mechanism, which moves underground using vibrations, was proposed. The internal ground resistance decreases when imparting vibrations because the ground particles move and behave like a fluid. On the other hand, the inner ground resistance increases after imparting vibrations because the ground was compacted. The proposed mechanism moves underground while changing the ground condition. This study investigated the relationship between internal ground resistance force and vibration kinds because this relationship helps move underground. In the experiment, inner ground resistance force was measured when an object vibrating was dragged on the ground. In the results, the inner ground resistance force is increased by the vibration whose vibratory force is low. On the other hand, it is decreased by the vibration whose vibratory force is high. This knowledge is valuable for designing the rover’s underground movement using vibrations.

关键词： Vibrations Resistance Knowledge engineering Mechatronics Planets Force Land surface

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