Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593804
Kuo Chen, Sehoon Ha, K. Yamane
The hardware compatibility of legged locomotion is often illustrated by Zero Moment Point (ZMP) that has been extensively studied for decades. One of the most popular models for computing the ZMP is the linear inverted pendulum (LIP) model that expresses ZMP as a linear function of the center of mass(COM) and its acceleration. In the real world, however, it may not accurately predict the true ZMP of hardware due to various reasons such as unmodeled dynamics and differences between simulation model and hardware. In this paper, we aim to improve the theoretical ZMP model by learning the real hardware dynamics from experimental data. We first optimize the motion plan using the theoretical ZMP model and collect COP data by executing the motion on a force plate. We then train a new ZMP model that maps the motion plan variable to the actual ZMP and use the learned model for finding a new hardware-compatible motion plan. Through various locomotion tasks of a quadruped, we demonstrate that motions planned for the learned ZMP model are compatible on hardware when those for the theoretical ZMP model are not. Furthermore, experiments using ZMP models with different complexities reveal that overly complex models may suffer from over-fitting even though they can potentially represent more complex, unmodeled dynamics.
腿式运动的硬件兼容性通常用零力矩点(Zero Moment Point, ZMP)来说明，这一概念已经被广泛研究了几十年。计算ZMP最流行的模型之一是线性倒立摆(LIP)模型，它将ZMP表示为质心(COM)及其加速度的线性函数。然而，在现实世界中，由于各种原因，如未建模的动力学和仿真模型与硬件之间的差异，它可能无法准确预测硬件的真实ZMP。在本文中，我们旨在通过从实验数据中学习真实的硬件动态来改进理论ZMP模型。我们首先使用理论ZMP模型优化运动方案，并通过在测力板上执行运动来收集COP数据。然后，我们训练一个新的ZMP模型，该模型将运动计划变量映射到实际的ZMP，并使用学习到的模型来寻找新的硬件兼容的运动计划。通过四足动物的各种运动任务，我们证明了学习ZMP模型所规划的运动在硬件上是兼容的，而理论ZMP模型所规划的运动在硬件上是不兼容的。此外，使用不同复杂性的ZMP模型的实验表明，过于复杂的模型可能会遭受过拟合，即使它们可能代表更复杂、未建模的动态。
{"title":"Learning Hardware Dynamics Model from Experiments for Locomotion Optimization","authors":"Kuo Chen, Sehoon Ha, K. Yamane","doi":"10.1109/IROS.2018.8593804","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593804","url":null,"abstract":"The hardware compatibility of legged locomotion is often illustrated by Zero Moment Point (ZMP) that has been extensively studied for decades. One of the most popular models for computing the ZMP is the linear inverted pendulum (LIP) model that expresses ZMP as a linear function of the center of mass(COM) and its acceleration. In the real world, however, it may not accurately predict the true ZMP of hardware due to various reasons such as unmodeled dynamics and differences between simulation model and hardware. In this paper, we aim to improve the theoretical ZMP model by learning the real hardware dynamics from experimental data. We first optimize the motion plan using the theoretical ZMP model and collect COP data by executing the motion on a force plate. We then train a new ZMP model that maps the motion plan variable to the actual ZMP and use the learned model for finding a new hardware-compatible motion plan. Through various locomotion tasks of a quadruped, we demonstrate that motions planned for the learned ZMP model are compatible on hardware when those for the theoretical ZMP model are not. Furthermore, experiments using ZMP models with different complexities reveal that overly complex models may suffer from over-fitting even though they can potentially represent more complex, unmodeled dynamics.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"95 1","pages":"3807-3814"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74099106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593867
Takuya Ohashi, Y. Ikegami, Kazuki Yamamoto, W. Takano, Yoshihiko Nakamura
This paper discusses video motion capture, namely, 3D reconstruction of human motion from multi-camera images. After the Part Confidence Maps are computed from each camera image, the proposed spatiotemporal filter is applied to deliver the human motion data with accuracy and smoothness for human motion analysis. The spatiotemporal filter uses the human skeleton and mixes temporal smoothing in two-time inverse kinematics computations. The experimental results show that the mean per joint position error was 26.1mm for regular motions and 38.8mm for inverted motions.
{"title":"Video Motion Capture from the Part Confidence Maps of Multi-Camera Images by Spatiotemporal Filtering Using the Human Skeletal Model","authors":"Takuya Ohashi, Y. Ikegami, Kazuki Yamamoto, W. Takano, Yoshihiko Nakamura","doi":"10.1109/IROS.2018.8593867","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593867","url":null,"abstract":"This paper discusses video motion capture, namely, 3D reconstruction of human motion from multi-camera images. After the Part Confidence Maps are computed from each camera image, the proposed spatiotemporal filter is applied to deliver the human motion data with accuracy and smoothness for human motion analysis. The spatiotemporal filter uses the human skeleton and mixes temporal smoothing in two-time inverse kinematics computations. The experimental results show that the mean per joint position error was 26.1mm for regular motions and 38.8mm for inverted motions.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"65 1","pages":"4226-4231"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75147721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593733
Congying Sui, Zerui Wang, Yunhui Liu
In this paper, we propose a novel 3D laparoscopic imaging system based on stereo-photogrammetry which is assisted by projecting patterns on the tissue surface. The proposed laparoscopic imaging system has three optic channels, two of which are responsible for stereo vision feedback and the other one is used for coded structured patterns projection. The projected patterns provide the robustness to homogeneous tissue surface since they add more features that can be relied on in the stereo matching. Image fiber bundles (100k pixels) and Gradient-index (GRIN) lenses are utilized to facilitate the remote image acquisition and miniaturization of the laparoscopic probe. Moreover, we adopt a digital micromirror device (DMD) and high-speed cameras to achieve fast pattern switching (up to 4 kHz) and high frame rate image acquisition. The system configuration allows for implementation of the time multiplexing pattern codification strategy in the 3D laparoscopic imaging system to enhance the reliability and resolution of the 3D surface reconstruction. A prototype is established, and various experiments are conducted. Comparative experimental results prove the advantages of our system design. The static and dynamic 3D reconstruction results validate the performance of the proposed 3D laparoscopic imaging system quantitatively and qualitatively.
{"title":"A 3D Laparoscopic Imaging System Based on Stereo-Photogrammetry with Random Patterns","authors":"Congying Sui, Zerui Wang, Yunhui Liu","doi":"10.1109/IROS.2018.8593733","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593733","url":null,"abstract":"In this paper, we propose a novel 3D laparoscopic imaging system based on stereo-photogrammetry which is assisted by projecting patterns on the tissue surface. The proposed laparoscopic imaging system has three optic channels, two of which are responsible for stereo vision feedback and the other one is used for coded structured patterns projection. The projected patterns provide the robustness to homogeneous tissue surface since they add more features that can be relied on in the stereo matching. Image fiber bundles (100k pixels) and Gradient-index (GRIN) lenses are utilized to facilitate the remote image acquisition and miniaturization of the laparoscopic probe. Moreover, we adopt a digital micromirror device (DMD) and high-speed cameras to achieve fast pattern switching (up to 4 kHz) and high frame rate image acquisition. The system configuration allows for implementation of the time multiplexing pattern codification strategy in the 3D laparoscopic imaging system to enhance the reliability and resolution of the 3D surface reconstruction. A prototype is established, and various experiments are conducted. Comparative experimental results prove the advantages of our system design. The static and dynamic 3D reconstruction results validate the performance of the proposed 3D laparoscopic imaging system quantitatively and qualitatively.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"51 1","pages":"1276-1282"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74879173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8594403
Carly M. Thalman, Quoc P. Lam, P. Nguyen, Saivimal Sridar, Panagiotis Polygerinos
This paper investigates the design of a soft elbow exosuit capable of providing supplemental lifting assistance by reducing muscle activity of the bicep muscle. The aim is to improve the efficiency and endurance of workers who are tasked with repetitive lifting. The design consists of an array of pneumatically pressurized soft actuators, which are encased in nylon fabric that allows for a high force-to-weight ratio of 211.SN/g. An analytical model governing the bending behavior of two consecutive actuators and torque generated by the exosuit is developed, with test results showing less than 10% error from the theoretical model. An elbow joint torque value of 27.6N.m is achieved at 300kPa, which is comparable to the 30N.m maximum set by OSHA requirements in the USA. Further testing with a healthy participant is performed using surface electromyography (sEMG) sensors and a motion capture system to assess the capabilities of the exosuit to provide active assistance to the bicep during isometric and concentric contractions. Measurable assistance to lifting is observed with minimal obstruction to the user's range of motion for all experiments.
本文研究了一种软肘外装的设计，能够通过减少肱二头肌的肌肉活动来提供补充的举重辅助。目的是提高工人的效率和耐力，他们的任务是重复举起。该设计由一系列气动加压软执行器组成，这些执行器包裹在尼龙织物中，可以实现211 sn /g的高力重比。建立了控制两个连续致动器弯曲行为和外太空服产生的扭矩的解析模型，试验结果表明与理论模型误差小于10%。肘关节转矩值为27.6N。在300kPa时达到m，与30N相当。美国职业安全与健康管理局(OSHA)规定的最大值。对健康参与者进行进一步的测试，使用表面肌电图(sEMG)传感器和运动捕捉系统来评估外伤服在等长和同心收缩期间为二头肌提供主动辅助的能力。在所有实验中，观察到可测量的举重辅助，对用户运动范围的阻碍最小。
{"title":"A Novel Soft Elbow Exosuit to Supplement Bicep Lifting Capacity","authors":"Carly M. Thalman, Quoc P. Lam, P. Nguyen, Saivimal Sridar, Panagiotis Polygerinos","doi":"10.1109/IROS.2018.8594403","DOIUrl":"https://doi.org/10.1109/IROS.2018.8594403","url":null,"abstract":"This paper investigates the design of a soft elbow exosuit capable of providing supplemental lifting assistance by reducing muscle activity of the bicep muscle. The aim is to improve the efficiency and endurance of workers who are tasked with repetitive lifting. The design consists of an array of pneumatically pressurized soft actuators, which are encased in nylon fabric that allows for a high force-to-weight ratio of 211.SN/g. An analytical model governing the bending behavior of two consecutive actuators and torque generated by the exosuit is developed, with test results showing less than 10% error from the theoretical model. An elbow joint torque value of 27.6N.m is achieved at 300kPa, which is comparable to the 30N.m maximum set by OSHA requirements in the USA. Further testing with a healthy participant is performed using surface electromyography (sEMG) sensors and a motion capture system to assess the capabilities of the exosuit to provide active assistance to the bicep during isometric and concentric contractions. Measurable assistance to lifting is observed with minimal obstruction to the user's range of motion for all experiments.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"1 1","pages":"6965-6971"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74899558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593821
F. Asano
Stealth walking is a way of walking carefully and noiselessly, and is an approach to stable legged locomotion of underactuated robotic walkers on irregular terrains. This paper proposes a method for generating a high-speed stealth walking gait without including double-limb support phase, and discusses the effect of upper-body control and semicircular feet on the gait properties. First, we introduce a model of a 3-link planar underactuated biped with an upper body and semicircular feet, and derive the approximate target initial state of the upper body by using the linearized equation of motion. Second, we conduct numerical simulations of the nonlinear model to observe the typical stealth walking gaits, and analyze the changing tendency of the upper body motion with respect to the foot radius. Furthermore, we discuss the advantage of semicircular feet through parametric studies of the gait efficiencies.
{"title":"High-Speed Stealth Walking of Underactuated Biped Utilizing Effects of Upper-Body Control and Semicircular Feet","authors":"F. Asano","doi":"10.1109/IROS.2018.8593821","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593821","url":null,"abstract":"Stealth walking is a way of walking carefully and noiselessly, and is an approach to stable legged locomotion of underactuated robotic walkers on irregular terrains. This paper proposes a method for generating a high-speed stealth walking gait without including double-limb support phase, and discusses the effect of upper-body control and semicircular feet on the gait properties. First, we introduce a model of a 3-link planar underactuated biped with an upper body and semicircular feet, and derive the approximate target initial state of the upper body by using the linearized equation of motion. Second, we conduct numerical simulations of the nonlinear model to observe the typical stealth walking gaits, and analyze the changing tendency of the upper body motion with respect to the foot radius. Furthermore, we discuss the advantage of semicircular feet through parametric studies of the gait efficiencies.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"240 1","pages":"4375-4380"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72774988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593834
Hyunsoo Yang, Nicolas Staub, A. Franchi, Dongjun Lee
The MAGMaS (Multiple Aerial-Ground Manipulator System) was proposed in [1] as a heterogeneous system composed of multiple ground (mobile) manipulators and aerial robots to collaboratively manipulate a long/large-sized object and demonstrated therein for rigid load manipulation. Here, we extend this result of [1] to the case of load manipulation with flexibility, which is crucial for long/slender object manipulation, yet, not considered in [1]. We first provide a rigorous modeling of the load flexibility and its effects on the MAGMaS dynamics. We then propose a novel collaborative control framework for flexible load-tip pose tracking, where the ground manipulator provides slower nominal pose tracking with overall load weight holding, whereas the aerial robot allows for faster vibration suppression with some load weight sharing. We also discuss the issue of controllability stemming from that the aerial robot provides less number of actuation than the modes of the load flexibility; and elucidate some peculiar conditions for this vibration suppression controllability. Simulations are also performed to demonstrate the effectiveness of the proposed theory.
{"title":"Modeling and Control of Multiple Aerial-Ground Manipulator System (MAGMaS) with Load Flexibility","authors":"Hyunsoo Yang, Nicolas Staub, A. Franchi, Dongjun Lee","doi":"10.1109/IROS.2018.8593834","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593834","url":null,"abstract":"The MAGMaS (Multiple Aerial-Ground Manipulator System) was proposed in [1] as a heterogeneous system composed of multiple ground (mobile) manipulators and aerial robots to collaboratively manipulate a long/large-sized object and demonstrated therein for rigid load manipulation. Here, we extend this result of [1] to the case of load manipulation with flexibility, which is crucial for long/slender object manipulation, yet, not considered in [1]. We first provide a rigorous modeling of the load flexibility and its effects on the MAGMaS dynamics. We then propose a novel collaborative control framework for flexible load-tip pose tracking, where the ground manipulator provides slower nominal pose tracking with overall load weight holding, whereas the aerial robot allows for faster vibration suppression with some load weight sharing. We also discuss the issue of controllability stemming from that the aerial robot provides less number of actuation than the modes of the load flexibility; and elucidate some peculiar conditions for this vibration suppression controllability. Simulations are also performed to demonstrate the effectiveness of the proposed theory.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"85 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73036288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593681
Justin W. Hart, Rishi Shah, Sean Kirmani, Nick Walker, Kathryn Baldauf, Nathan John, P. Stone
Many robotics applications involve navigating to positions specified in terms of their semantic significance. A robot operating in a hotel may need to deliver room service to a named room. In a hospital, it may need to deliver medication to a patient's room. The Building-Wide Intelligence Project at UT Austin has been developing a fleet of autonomous mobile robots, called BWIBots, which perform tasks in the computer science department. Tasks include guiding a person, delivering a message, or bringing an object to a location such as an office, lecture hall, or classroom. The process of constructing a map that a robot can use for navigation has been simplified by modern SLAM algorithms. The attachment of semantics to map data, however, remains a tedious manual process of labeling locations in otherwise automatically generated maps. This paper introduces a system called PRISM to automate a step in this process by enabling a robot to localize door signs – a semantic markup intended to aid the human occupants of a building – and to annotate these locations in its map.
{"title":"PRISM: Pose Registration for Integrated Semantic Mapping","authors":"Justin W. Hart, Rishi Shah, Sean Kirmani, Nick Walker, Kathryn Baldauf, Nathan John, P. Stone","doi":"10.1109/IROS.2018.8593681","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593681","url":null,"abstract":"Many robotics applications involve navigating to positions specified in terms of their semantic significance. A robot operating in a hotel may need to deliver room service to a named room. In a hospital, it may need to deliver medication to a patient's room. The Building-Wide Intelligence Project at UT Austin has been developing a fleet of autonomous mobile robots, called BWIBots, which perform tasks in the computer science department. Tasks include guiding a person, delivering a message, or bringing an object to a location such as an office, lecture hall, or classroom. The process of constructing a map that a robot can use for navigation has been simplified by modern SLAM algorithms. The attachment of semantics to map data, however, remains a tedious manual process of labeling locations in otherwise automatically generated maps. This paper introduces a system called PRISM to automate a step in this process by enabling a robot to localize door signs – a semantic markup intended to aid the human occupants of a building – and to annotate these locations in its map.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"81 1","pages":"896-902"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73266935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593521
Firas Abi-Farraj, Bernd Henze, Alexander Werner, M. Panzirsch, C. Ott, M. Roa
Robotic teleoperation is a key technology for a wide variety of fields. Teleoperating a humanoid in particular is essential as it allows the user to act remotely on an interface designed especially for humans, e.g., in a space station, or operating tools and machinery in disaster scenarios. This paper presents a ‘task-relevant’ haptic interface for humanoid teleoperation, which bridges the gap between the task at hand and the balance of the robot. The operator is given command over the humanoid's hands and is informed through haptic cues about the impact of her/his potential actions on the robot’ stability. Moreover, a null-space autonomous controller acts in the operator's null-space to provide her/him with a wider workspace and help in the successful execution of the task. The architecture is designed to top an existing compliance controller for a torque-controlled humanoid robot. Experiments on the humanoid robot TORO are reported to demonstrate the feasibility and effectiveness of the approach.
{"title":"Humanoid Teleoperation Using Task-Relevant Haptic Feedback","authors":"Firas Abi-Farraj, Bernd Henze, Alexander Werner, M. Panzirsch, C. Ott, M. Roa","doi":"10.1109/IROS.2018.8593521","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593521","url":null,"abstract":"Robotic teleoperation is a key technology for a wide variety of fields. Teleoperating a humanoid in particular is essential as it allows the user to act remotely on an interface designed especially for humans, e.g., in a space station, or operating tools and machinery in disaster scenarios. This paper presents a ‘task-relevant’ haptic interface for humanoid teleoperation, which bridges the gap between the task at hand and the balance of the robot. The operator is given command over the humanoid's hands and is informed through haptic cues about the impact of her/his potential actions on the robot’ stability. Moreover, a null-space autonomous controller acts in the operator's null-space to provide her/him with a wider workspace and help in the successful execution of the task. The architecture is designed to top an existing compliance controller for a torque-controlled humanoid robot. Experiments on the humanoid robot TORO are reported to demonstrate the feasibility and effectiveness of the approach.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"8 1","pages":"5010-5017"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75530947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593759
M. Logothetis, G. Karras, Shahab Heshmati-alamdari, Panagiotis Vlantis, K. Kyriakopoulos
This paper presents the design of a vision-based object grasping and motion control architecture for a mobile manipulator system. The optimal grasping areas of the object are estimated using the partial point cloud acquired from an onboard RGB-D sensor system. The reach-to-grasp motion of the mobile manipulator is handled via a Nonlinear Model Predictive Control scheme. The controller is formulated accordingly in order to allow the system to operate in a constrained workspace with static obstacles. The goal of the proposed scheme is to guide the robot's end-effector towards the optimal grasping regions with guaranteed input and state constraints such as occlusion and obstacle avoidance, workspace boundaries and field of view constraints. The performance of the proposed strategy is experimentally verified using an 8 Degrees of Freedom KUKA Youbot in different reach-to-grasp scenarios.
{"title":"A Model Predictive Control Approach for Vision-Based Object Grasping via Mobile Manipulator","authors":"M. Logothetis, G. Karras, Shahab Heshmati-alamdari, Panagiotis Vlantis, K. Kyriakopoulos","doi":"10.1109/IROS.2018.8593759","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593759","url":null,"abstract":"This paper presents the design of a vision-based object grasping and motion control architecture for a mobile manipulator system. The optimal grasping areas of the object are estimated using the partial point cloud acquired from an onboard RGB-D sensor system. The reach-to-grasp motion of the mobile manipulator is handled via a Nonlinear Model Predictive Control scheme. The controller is formulated accordingly in order to allow the system to operate in a constrained workspace with static obstacles. The goal of the proposed scheme is to guide the robot's end-effector towards the optimal grasping regions with guaranteed input and state constraints such as occlusion and obstacle avoidance, workspace boundaries and field of view constraints. The performance of the proposed strategy is experimentally verified using an 8 Degrees of Freedom KUKA Youbot in different reach-to-grasp scenarios.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"13 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75725542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.1109/IROS.2018.8593418
T. Takayama, C. Tsai, M. Kaneko
This video presents a microfluidic phenomenon called “Virtual Vortex Gear (VVG)” and an application of it. The video contains 4 parts and is described as follows: The 1st part shows an application of VVG as a controllable valve in a micro fluidic system and the on and off of the valve are controlled by different flow speeds. The valve is turned on when the flow speed is high enough, and vice versa. The 2nd part shows the generation of VVG and its mechanism. When the flow speed, which is proportional to Reynolds Number, is gradually increased, the flow pattern evolves in the order as (1)parallel streamlines, (2)one vortex, (3)two vortices and eventually (4)three vortices including the last vortex inside the circular chamber. The evolution indicates the transmission of flow energy from the main stream to the inside of the chamber when the flow speed is over a certain range. In addition, every two adjacent vortices rotate in opposite directions which is just like a set of gears, and that is why we named it “VVG”. In the 3rd part, an application of VVG for chemical injection is demonstrated. A colored liquid is represented for the chemical and is surrounded by different sheath flow for the control of injection locations. It is found that only the fluid in a particular pinpoint can be injected into the target chamber. Furthermore, the complex but stable 3D flow patterns are visualized from the video. The last part of the video shows that different amount of chemical injection can be performed in different chambers along the same main stream and the distribution of the color is gradually become uniform by spontaneous diffusing.
{"title":"On-Chip Virtual Vortex Gear and Its Application","authors":"T. Takayama, C. Tsai, M. Kaneko","doi":"10.1109/IROS.2018.8593418","DOIUrl":"https://doi.org/10.1109/IROS.2018.8593418","url":null,"abstract":"This video presents a microfluidic phenomenon called “Virtual Vortex Gear (VVG)” and an application of it. The video contains 4 parts and is described as follows: The 1st part shows an application of VVG as a controllable valve in a micro fluidic system and the on and off of the valve are controlled by different flow speeds. The valve is turned on when the flow speed is high enough, and vice versa. The 2nd part shows the generation of VVG and its mechanism. When the flow speed, which is proportional to Reynolds Number, is gradually increased, the flow pattern evolves in the order as (1)parallel streamlines, (2)one vortex, (3)two vortices and eventually (4)three vortices including the last vortex inside the circular chamber. The evolution indicates the transmission of flow energy from the main stream to the inside of the chamber when the flow speed is over a certain range. In addition, every two adjacent vortices rotate in opposite directions which is just like a set of gears, and that is why we named it “VVG”. In the 3rd part, an application of VVG for chemical injection is demonstrated. A colored liquid is represented for the chemical and is surrounded by different sheath flow for the control of injection locations. It is found that only the fluid in a particular pinpoint can be injected into the target chamber. Furthermore, the complex but stable 3D flow patterns are visualized from the video. The last part of the video shows that different amount of chemical injection can be performed in different chambers along the same main stream and the distribution of the color is gradually become uniform by spontaneous diffusing.","PeriodicalId":6640,"journal":{"name":"2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)","volume":"90 1","pages":"5544-5544"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72551746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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