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K-BMPC: Derivative-based Koopman Bilinear Model Predictive Control for Tractor-Trailer Trajectory Tracking with Unknown Parameters

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arXiv 2023年

作者： Wang, Zehao Zhang, Han Wang, Jingchuan Department of Automation Institute of Medical Robotics Shanghai Jiao Tong University Key Laboratory of System Control and Information Processing Ministry of Education of China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai200240 China

Nonlinear dynamics bring difficulties to controller design for control-affine systems such as tractor-trailer vehicles, especially when the parameters in the dynamics are unknown. To address this constraint, we propose a derivative-based lifting function construction method, show that the corresponding infinite dimensional Koopman bilinear model over the lifting function is equivalent to the original control-affine system. Further, we analyze the propagation and bounds of state prediction errors caused by the truncation in derivative order. The identified finite dimensional Koopman bilinear model would serve as predictive model in the next step. Koopman Bilinear Model Predictive control (K-BMPC) is proposed to solve the trajectory tracking problem. We linearize the bilinear model around the estimation of the lifted state and control input. Then the bilinear Model Predictive Control problem is approximated by a quadratic programming problem. Further, the estimation is updated at each iteration until the convergence is reached. Moreover, we implement our algorithm on a tractor-trailer system, taking into account the longitudinal and side slip effects. The open-loop simulation shows the proposed Koopman bilinear model captures the dynamics with unknown parameters and has good prediction performance. Closed-loop tracking results show the proposed K-BMPC exhibits elevated tracking precision with the commendable computational efficiency. The experimental results demonstrate the feasibility of K-BMPC. © 2023, CC BY-NC-SA.

关键词： Model predictive control

Optimal Energy Shaping Control for a Backdrivable Hip Exoskeleton

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Optimal Energy Shaping Control for a Backdrivable Hip Exoske...

American Control Conference (ACC)

作者： Jiefu Zhang Jianping Lin Vamsi Peddinti Robert D. Gregg Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China Robotics University of Michigan Ann Arbor MI USA

Task-dependent controllers widely used in exoskeletons track predefined trajectories, which overly constrain the volitional motion of individuals with remnant voluntary mobility. Energy shaping, on the other hand, provides task-invariant assistance by altering the human body’s dynamic characteristics in the closed loop. While human-exoskeleton systems are often modeled using Euler-Lagrange equations, in our previous work we modeled the system as a port-controlled-Hamiltonian system, and a task-invariant controller was designed for a knee-ankle exoskeleton using interconnection-damping assignment passivity-based control. In this paper, we extend this framework to design a controller for a backdrivable hip exoskeleton to assist multiple tasks. A set of basis functions that contains information of kinematics is selected and corresponding coefficients are optimized, which allows the controller to provide torque that fits normative human torque for different activities of daily life. Human-subject experiments with two able-bodied subjects demonstrated the controller’s capability to reduce muscle effort across different tasks.

关键词：

Hitchhiker: A Quadrotor Aggressively Perching on a Moving Inclined Surface Using Compliant Suction Cup Gripper

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arXiv 2022年

作者： Liu, Sensen Wang, Zhaoying Sheng, Xinjun Dong, Wei The State Key Laboratory of Mechanical System and Vibration Robotics Institute School of Mechanical and Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai China

Perching on the surface of moving objects, like vehicles, could extend the flight time and range of quadrotors. Suction cups are usually adopted for surface attachment due to their durability and large adhesive force. To seal on a surfaces, suction cups must be aligned with the surface and possess proper relative tangential velocity. However, quadrotors' attitude and relative velocity errors would become significant when the object surface is moving and inclined. To address this problem, we proposed a real-time trajectory planning algorithm. The time-optimal aggressive trajectory is efficiently generated through multimodal search in a dynamic time-domain. The velocity errors relative to the moving surface are alleviated. To further adapt to the residual errors, we design a compliant gripper using self-sealing cups. Multiple cups in different directions are integrated into a wheel-like mechanism to increase the tolerance to attitude errors. The wheel mechanism also eliminates the requirement of matching the attitude and tangential velocity. Extensive tests are conducted to perch on static and moving surfaces at various inclinations. Results demonstrate that our proposed system enables a quadrotor to reliably perch on moving inclined surfaces (up to 1.07m/s and 90◦) with a success rate of 70% or higher. The efficacy of the trajectory planner is also validated. Our gripper has larger adaptability to attitude errors and tangential velocities than conventional suction cup grippers. The success rate increases by 45% in dynamic perches. Copyright © 2022, The Authors. All rights reserved.

关键词： Grippers

A Method for Measurement of Workpiece Form Deviations Based on Machine Vision

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SSRN

SSRN 2022年

作者： Zhang, Wei Han, Zongwang Li, Yang Rong, Weibin Zheng, Hongyu Cheng, Xiang School of Mechanical Engineering Shandong University of Technology Zibo255000 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China

Machine vision has been studied for measurements of workpiece form deviations due to its ease for automation. However, the measurement accuracy limits its wide implementation in industrial applications. In this study, a method based on machine vision for measurement of straightness, roundness, and cylindricity of a workpiece is presented. A subsumed line search algorithm and an improved particle swarm optimization algorithm are proposed to evaluate the straightness and roundness deviations of the workpiece. Moreover, an image evaluation method of cylindricity deviation by the least square fitting of circle’s center coordinates is investigated. An image acquisition system incorporating image correction and sub-pixel edge positioning technology is developed. Performance of the developed system is evaluated against the measurement results of the standard cylindricity measuring instrument. The differences in measurement of straightness, roundness, and cylindricity are -4.69μm, 3.98μm, and 5.33μm, respectively. The proposed method would provide a viable industrial solution for measurement of workpiece form deviations. © 2022, The Authors. All rights reserved.

关键词： Computer vision

Perching on Moving Inclined Surfaces using Uncertainty Tolerant Planner and Thrust Regulation

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arXiv 2022年

作者： Liu, Sensen Hu, Wenkang Wang, Zhaoying Dong, Wei Sheng, Xinjun The State Key Laboratory of Mechanical System and Vibration Robotics Institute School of Mechanical and Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai China

Quadrotors with the ability to perch on moving inclined surfaces can save energy and extend their travel distance by leveraging ground vehicles. Achieving dynamic perching places high demands on the performance of trajectory planning and terminal state accuracy in SE(3). However, in the perching process, uncertainties in target surface prediction, tracking control and external disturbances may cause trajectory planning failure or lead to unacceptable terminal errors. To address these challenges, we first propose a trajectory planner that considers adaptation to uncertainties in target prediction and tracking control. To facilitate this work, the reachable set of quadrotors’ states is first analyzed. The states whose reachable sets possess the largest coverage probability for uncertainty targets, are defined as optimal waypoints. Subsequently, an approach to seek local optimal waypoints for static and moving uncertainty targets is proposed. A real-time trajectory planner based on optimized waypoints is developed accordingly. Secondly, thrust regulation is also implemented in the terminal attitude tracking stage to handle external disturbances. When a quadrotor’s attitude is commanded to align with target surfaces, the thrust is optimized to minimize terminal errors. This makes the terminal position and velocity be controlled in closed-loop manner. Therefore, the resistance to disturbances and terminal accuracy is improved. Extensive simulation experiments demonstrate that our methods can improve the accuracy of terminal states under uncertainties. The success rate is approximately increased by 50% compared to the two-end planner without thrust regulation. Perching on the rear window of a car is also achieved using our proposed heterogeneous cooperation system outdoors. This validates the feasibility and practicality of our methods. Copyright © 2022, The Authors. All rights reserved.

关键词： Trajectories

Real-Time Stereo Matching Networks Based on Multi-Modal and Sparse-Dense Fusion

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SSRN

SSRN 2023年

作者： Zhang, Xi Wu, Xiaojun Liang, Guoyuan School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen Shenzhen518055 China Guangdong Provincial Key Laboratory of Robotics and Intelligent System Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China

Binocular depth estimation models based on deep learning are difficult to balance accuracy and efficiency, and often occupy a lot of memory during inference. This paper proposes a new, concise and easily scalable model architecture based on disparity iterative optimization, Fusion-Stereo, which can achieve real-time inference speed and low memory occupation on the basis of ensuring excellent prediction accuracy. Based on the observation of different modal information of image texture feature, matching similarity feature and disparity feature, we propose a new disparity residual prediction module based on multi-modal information coding and fusion to help the adaptive propagation of reliable disparity information in spatial dimension and disparity dimension. In order to improve the reliability of depth prediction, we design an efficient fusion mechanism between Fusion-Stereo and external priori data sources, and introduce sparse disparity priori into the model to facilitate the dense disparity prediction, while ensuring that the inference speed and memory occupation are basically unchanged. © 2023, The Authors. All rights reserved.

关键词： Stereo vision

A Simple Robotic Cell Transportation Method Based on Narrow-necked Micropipette

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A Simple Robotic Cell Transportation Method Based on Narrow-...

第43届中国控制会议

作者： Shaojie Fu Jinyu Qiu Ripeng Zhu Ruimin Li Detian Zhang Zijian Guo Mingzhu Sun Xin Zhao Qili Zhao National Key Laboratory of Intelligent Tracking and Forecasting folnfectious Diseases Engineering Research Center of Trusted Behavior IntelligenceMinistry of EducationTianjin Key Laboratory of Intelligent Robotic (tikLIR)Institute of Robotics and Automatic Information System(IRAIS)Nankai University Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University

ISBN: (数字)9789887581581

ISBN: (纸本)9798350366907

Cell transportation has a wide range of applications in biological and medical research.A key step in cell transportation is to aspirate a single cell into micropipette and hold it at a designated *** current manual operations highly rely on the experience of the experimenters,while automated operations rely on complex control algorithms,which limits the promotion and application of transportation *** paper proposes a simple robotic cell transportation method using narrow-necked micropipette to address this ***,this paper proposes a fabrication method of a narrow-necked micropipette,which is developed to aspirate in and accurately stop cell at the designated narrow-necked ***,whether the cell has been stuck at the designated narrow-neck position is detected based on the changes in image ***,the minimum aspiration force for the cell to be held at the designated narrow-necked position is determined to reduce mechanical damage to the *** to the experimental results of 12 porcine oocytes,this method can aspirate the cell in and hold the designated position in 1.803 seconds on average,which is about 2 times faster than the commonly used transportation methods,and the success rate of cell holding reaches up to 100%.

关键词： Narrow-necked micropipette cell transportation position detection minimal injury holding force

MRI-guided robot intervention—current state-of-the-art and new challenges

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Med-X 2023年第1期1卷 1-41页

作者： Huang, Shaoping Lou, Chuqian Zhou, Ying He, Zhao Jin, Xuejun Feng, Yuan Gao, Anzhu Yang, Guang-Zhong Institute of Medical Robotics and School of Biomedical Engineering Shanghai Jiao Tong University Shanghai China National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT) Shanghai Jiao Tong University Shanghai China Materials and Technology Center of Robotics Empa Dübendorf Switzerland State Key Lab of Metal Matrix Composites and School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai China Institute of Medical Robotics and Department of Automation Shanghai Jiao Tong University Shanghai China The Key Laboratory of System Control and Information Processing Ministry of Education Shanghai China

Magnetic Resonance Imaging (MRI) is now a widely used modality for providing multimodal, high-quality soft tissue contrast images with good spatiotemporal resolution but without subjecting patients to ionizing radiation. In addition to its diagnostic potential, its future theranostic value lies in its ability to provide MRI-guided robot intervention with combined structural and functional mapping, as well as integrated instrument localization, target recognition, and in situ, in vivo monitoring of the therapeutic efficacy. Areas of current applications include neurosurgery, breast biopsy, cardiovascular intervention, prostate biopsy and radiotherapy. Emerging applications in targeted drug delivery and MRI-guided chemoembolization are also being pursued. Whilst promising progress has been made in recent years, there are still significant basic science research and engineering challenges. This paper provides a comprehensive review of the current state-of-the-art in MRI-guided robot intervention and allied technologies in actuation, sensing, new materials, interventional instruments, and interactive/real-time MRI. Potential future research directions and new clinical developments are also discussed.

关键词： MRI-guided robot intervention Actuation Sensing Materials Interventional instruments Interactive/realtime MRI

Joint Design of Radar Receive Filter and Unimodular ISAC Waveform with Sidelobe Level Control

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arXiv 2025年

作者： Zhang, Kecheng Liu, Ya-Feng Wang, Zhongbin Yuan, Weijie Keskin, Musa Furkan Wymeersch, Henk Xia, Shuqiang School of System Design and Intelligent Manufacturing The Shenzhen Key Laboratory of Robotics and Computer Vision Southern University of Science and Technology Shenzhen518055 China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Department of Electrical Engineering Chalmers University of Technology Gothenburg41296 Sweden ZTE Corporation The State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen518055 China

Integrated sensing and communication (ISAC) has been considered a key feature of next-generation wireless networks. This paper investigates the joint design of the radar receive filter and dual-functional transmit waveform for the multiple-input multiple-output (MIMO) ISAC system. While optimizing the mean square error (MSE) of the radar receive spatial response and maximizing the achievable rate at the communication receiver, besides the constraints of full-power radar receiving filter and unimodular transmit sequence, we control the maximum range sidelobe level, which is often overlooked in existing ISAC waveform design literature, for better radar imaging performance. To solve the formulated optimization problem with convex and nonconvex constraints, we propose an inexact augmented Lagrangian method (ALM) algorithm. For each subproblem in the proposed inexact ALM algorithm, we custom-design a block successive upper-bound minimization (BSUM) scheme with closed-form solutions for all blocks of variable to enhance the computational efficiency. Convergence analysis shows that the proposed algorithm is guaranteed to provide a stationary and feasible solution. Extensive simulations are performed to investigate the impact of different system parameters on communication and radar imaging performance. Comparison with the existing works shows the superiority of the proposed algorithm. © 2025, CC BY-NC-SA.

关键词： Mean square error