Weidong Chen

Shanghai Jiao Tong University | SJTU · Department of Automation

Endoluminal and endocavitary intervention via natural orifices of the body is an emerging trend in medicine, further underpinning the future of early intervention and precision surgery. This motivates the development of small continuum robots to navigate freely in confined and tortuous environment. The trade-off between a large range of motion and...

Continuum robots are being increasingly used in minimally invasive surgery because of their high dexterity. Most studies have adopted the redundancy approach-increase the number of actuation degrees of freedom (DOFs)-to improve the performance of robots. However, a continuum robot with a large number of actuation DOFs will feature a complex structu...

Achieving the balance between stiffness and range of motion (ROM) in continuum manipulators is a primary design challenge. To tackle this design trade-off, this paper introduces a novel notched-tube continuum manipulator (NTCM) called the Steerable Cross-axis Notched (SCAN) manipulator. It achieves this by integrating asymmetric cross-axis notches...

Sparse feature based visual-inertial SLAM system shows great potential for accurate pose estimation in real-time, especially for low-cost devices. However, the feature correspondence outliers inevitably degrade the localization accuracy, or cause failures. Unlike the existing methods that eliminate outliers by fitting a geometric model, which have...

Cable-driven continuum robots are widely used for endoluminal intervention because of their dexterity and shape conforming steerability. However, body contact between the continuum robot and its surrounding anatomy is unavoidable, which imposes a potential safety risk, including vessel wall damage or even perforation. This paper presents an approac...

We study the transport-pick agents task scheduling (TPTS) problem in heterogeneous agents pickup and delivery (HAPD). Two functionally heterogeneous agent types, transport agents and pick agents, collaborate to execute multi-goal tasks subjecting to complex-schedule dependency. The objective is to plan a collective time-extended task schedule with...

Robotic telemedicine can provide timely treatment to critical patients in geographically remote locations. However, owing to the lack of depth information, occlusion of instrument, and view direction limitations, visual feedback from the patient to the clinician is typically unintuitive, which affects surgical safety. Herein, an omnidirectional aug...

4D imaging radars (4D radars) provide point clouds with range, azimuth, elevation as well as Doppler velocity. They are much cheaper sensors than LiDARs and can operate under extreme weather conditions. However, its drawbacks of high noise and sparsity would pose great challenges for SLAM. In this paper, we present a 4D radar-based SLAM framework b...

Force sensing is vital for situational awareness and safe interaction during minimally invasive surgery. Consequently, surgical robots with integrated force-sensing techniques ensure precise and safe operations. Over the past few decades, there has been considerable progress in force-sensing techniques for surgical robots. This review summarizes th...

With the rapidly growing demand for accurate localization in real-world environments, visual simultaneous localization and mapping (SLAM) has received significant attention in recent years. However, those existing methods still suffer from the degradation of localization accuracy in long-term changing environments. To address these problems, we pro...

Microactuators can autonomously convert external energy into specific mechanical motions. With the feature sizes varying from the micrometer to millimeter scale, microactuators offer many operation and control possibilities for miniaturized devices. In recent years, advanced microfluidic techniques have revolutionized the fabrication, actuation, an...

To achieve precise localization, autonomous vehicles usually rely on a multi-sensor perception system surrounding the mobile platform. Calibration is a time-consuming process, and mechanical distortion will cause extrinsic calibration errors. Therefore, we propose a lidar-visual-inertial odometry, which is combined with an adapted sliding window me...

Surgical endoscopes deployable through natural orifices are necessary to facilitate further reduction in invasiveness. However, the constant curvature deflection shapes of conventional instruments may result in tissue damage while navigating narrow tortuous variable curvature anatomy. A multi-contact-aided (MCA) continuum manipulator comprising spa...

A novel origami-inspired foldable pneumatic actuator is proposed in this paper to satisfy the comprehensive requirements in wearable assistive application. The pneumatic actuator combines the origami structure of designed Quadrangular-Expand pattern and the foldable pneumatic bellow. Integrated origami structure regulates the motion of actuator wit...

This paper presents the kinetostatic analysis of pneumatic bending soft actuator coupling with revolute joint, aimed to discover the bending performance of soft actuator wearing on physical joint of human body as exoskeleton. First, a new pneumatic bidirectional bending soft actuator is designed and its mechanical characteristic is obtained by expe...

Robotic telemedicine has a high potential to promote the development of future medicine. It enables the treatment of critical patients in geographically remote locations in time, and also particularly useful for avoiding infection risks during pandemics of infectious diseases. However, visual feedback from the patient’s side to the clinician’s side...

Medical robotics is a rapidly advancing discipline that is leading the evolution of robot-assisted surgery, personalized rehabilitation and assistance, and hospital automation. In China, both research and commercial developments in medical robotics have undergone exponential growth in recent years. In this review, we first give an overview of the c...

Visual localization of autonomous robots in dynamic scenes is a critical problem to be solved. Unlike the existing methods that regard the dynamic changes as outliers, we explore the hidden regularities of the long-term dynamic changes, and propose a new visual topological localization system. According to the regular pattern of feature existence c...

We formulate the problem of multi-robot path planning with due times (MRPP-DT), which is a variant of the classical path planning problem with task due times explicitly considered. The objectives are to obtain collision-free paths with the minimization of maximum lateness, total tardiness or total unit penalties. When task due times are available,...

Long-term scene changes present challenges to localization systems using a pre-built map. This paper presents a LiDAR-based system that can provide robust localization against those challenges. Our method starts with activation of a mapping process temporarily when global matching towards the pre-built map is unreliable. The temporary map will be m...

Visual-inertial odometry (VIO) shows high localization accuracy in many environments. However, the inevitable estimation drift is constantly accumulating, which even leads to failures. Hence, an efficient loop closing (LC) is necessary for correcting drift. Unlike most existing methods rely on pre-trained model, we propose an incremental hierarchic...

In the Heterogeneous Robots Task Scheduling (HTS) problem, multiple transport robots and multiple pick robots collaborate to achieve complex-schedule order-fulfillment tasks, and we want to obtain the collective time-extended task schedule with the minimization of makespan. As a typical strongly NP-hard integrated routing and scheduling problem, me...

Robust long-term visual localization is challenging for mobile robot, especially in changing environments, where the dynamic scene changes degrade localization accuracy, or even cause failures. Most of the existing methods eliminate dynamic changes as outliers, which strictly rely on the static world assumptions. Conversely, we efficiently exploit...

This article presents a study on pneumatic bending soft actuator (SA) coupling with revolute joint (RJ) with different boundary constraints (BCs), aimed to discover the bending performance of SA wearing on physical joint of human body as body joint actuators with different installation methods. First, a new pneumatic bidirectional bending SA is des...

We study the Transport and Pick Robots Task Scheduling (TPS) problem, in which two teams of specialized robots, transport robots and pick robots, collaborate to execute multi-station order fulfillment tasks in logistic environments. The objective is to plan a collective time-extended task schedule with the minimization of makespan. However, for thi...

Grasping objects in clutter is more difficult than grasping a separated single object. An important issue is that unsafe grasps may occur, in case, one object sits or leans on another, which could cause the collapse of objects. In addition, reachability of each object surrounded by other obstacles also has to be considered. So the order of multiple...

Current robotic endoluminal interventions require surgeons to hold a proximal joystick to control the distal flexible robot under 2-D X-ray guidance. However, the 2-D X-ray image is not intuitive, which not only increases the risk of surgical misoperation but also the workload of surgeons. Moreover, contact teleoperation exposes surgeons to the pot...

Soft robots characterize operational safety due to inherent compliance from their soft mechanism, whereas their mechanism enhances the difficulty in accurate closed-loop control. To explore their applicability in manipulation tasks, in this article, we propose a visual servoing pushing controller considering the effect of contact. The controller is...

We consider the uncalibrated vision-based control problem of robotic manipulators in this work. Though lots of approaches have been proposed to solve this problem, they usually require calibration (offline or online) of the camera parameters in the implementation, and the control performance may be largely affected by parameter estimation errors. I...

A new unsupervised learning method of depth and ego-motion using multiple masks from monocular video is proposed in this paper. The depth estimation network and the ego-motion estimation network are trained according to the constraints of depth and ego-motion without truth values. The main contribution of our method is to carefully consider the occ...

The world was unprepared for the COVID-19 pandemic, and recovery is likely to be a long process. Robots have long been heralded to take on dangerous, dull, and dirty jobs, often in environments that are unsuitable for humans. Could robots be used to fight future pandemics? We review the fundamental requirements for robotics for infectious disease m...

Cable-driven continuum manipulators have shown excellent benefits to work for endoluminal intervention. Demand of small diameter for confined anatomy limits the usage of multiple actuations, leading to limited DOFs and bending shapes. To address this problem, this letter proposes an omni-directional continuum manipulator with anisotropic bending sh...

Soft continuum robot is of superiority in the applications in unstructured environments due to its high flexibility and safe interaction ability. Accurate shape control is regarded as one of the prerequisites to improve its practicability. Considering the situation where the 3D position signals are not available, this paper investigates the vision-...

Automatic manipulation of deformable objects is a challenging problem. Improper operations, such as excessive stretching, collision, are easy to cause damages to the deformable objects. Thus, not only the final configuration but also the trajectory of the deformation is supposed to be controlled during the process of interaction. In this paper, a m...

Visual localization is a crucial component in the application of mobile robot and autonomous driving. Image retrieval is an efficient and effective technique in image-based localization methods. Due to the drastic variability of environmental conditions, e.g., illumination changes, retrieval-based visual localization is severely affected and become...

Object manipulation planning in clutter suffers from perception uncertainties due to occlusion, as well as action constraints required by collision avoidance. Partially observable Markov decision process (POMDP) provides a general model for planning under uncertainties. But a manipulation task usually have a large action space, which not only makes...

The production of wingbeat motion of flapping wing hovering flight is determined by the actuating, aerodynamic and inertia forces/moments, which influence the dynamic unsteadiness and controllability of flapping wing flying. This paper presents the feasible solution for cracking the problem of two degrees of freedom (two DoFs, namely, flapping and...

Accurate localization is essential for remote rover in scientific planet exploration missions. However, limited by energy supply, onboard computing capacity often cannot handle all multisensor fusion tasks simultaneously, which degrades localization performance rapidly. In this article, we propose a new ground station-assisted visual-inertial (VI)...

This paper proposes a novel method as an im-provement of the active fault detection method for eliminat-ing the negative influences generated by auxiliary signals used in it. In this method, the signals used for fault detec-tion are generated by the controller and are merged with control signals and therefore, the stability of the system can be rig...

Automatic cutting is an essential task in the field of robot-assisted surgery (RAS). In this paper, a novel vision-based cutting control algorithm is proposed to cut a deformable object along the pre-designed path with specified cutting depth. The method to model soft tissue considering viscoelasticity is developed, and unknown parameters of the de...

Visual localization is a crucial component in the application of mobile robot and autonomous driving. Image retrieval is an efficient and effective technique in image-based localization methods. Due to the drastic variability of environmental conditions, e.g.Su illumination, seasonal and weather changes, retrieval-based visual localization is sever...

The decline in muscle strength of the lower limbs because of ageing and diseases is the main reason why elderly and disabled have difficulty in standing and walking. In this paper, a transfer robot is designed to assist the elderly and disabled in standing and moving. The robot uses the traction assist method to lift the user, which can reduce the...

This paper addresses multi-robot task scheduling for two robot types arising from heterogeneous robotic order fulfillment systems. The heterogeneous multi-robot system comprises two types of robots with specialized and complementary capabilities to achieve long-duration and multi-station order fulfillment tasks on a logistic network. This problem i...

Due to the features of soft material such as softness, deformability and adaptability to constrained surroundings, soft manipulators can collide with external objects in some extent. To take the best advantage of this merit, this paper presents a method of visual servo considering collisions with obstacles for a soft manipulator. First of all, a co...

Although many vision-based control methods have been proposed for nonholonomic mobile robots, in their implementation, it is usually necessary to calibrate the camera intrinsic and/or extrinsic parameters using offline/online parameter estimation algorithms or online adaptation laws. To avoid the tediousness of camera calibration and to make the sy...

Robots inspired from marine organisms are tremendously developed for applications of underwater exploration, rescuing, navigation, etc. In this paper, we implement an uncalibrated visual servoing scheme to achieve accurate positioning performance of an octopus-tentacle-like soft robot arm. The image-based adaptive visual servoing controller is desi...

This article presents the system integration, sensing, and control of a novel modular soft-rigid pneumatic exoskeleton for lower limb. The proposed exoskeleton consists of three soft hinges (to drive the hip, knee, and ankle joints) and four rigid links (aligned with the waist, thigh, crus, and foot). Each soft hinge is made of and actuated by a cu...

Visual localization is a crucial problem in mobile robotics and autonomous driving. One solution is to retrieve images with known pose from a database for the localization of query images. However, in environments with drastically varying conditions (e.g. illumination changes, seasons, occlusion, dynamic objects), retrieval-based localization is se...

Purpose In the running of multiple automated guided vehicles (AGVs) in warehouses, delay problems in motions happen unavoidably as there might exist some disabled components of robots, the instability of networks and the interference of people walking. Under this case, robots would not follow the designed paths and the coupled relationship between...

In this research heterogeneous multi-agent routing strategy for a robot-and-picker-to-good order fulfillment system based on collaboration between mobile robots and human workers is proposed. As it is intractable to solve all agents’ routing problems as a large global optimization problem, individual agent’s routing is planned separately based on u...

As unmanned aerial vehicles (UAVs) are used in challenging environments to carry out various complex tasks, a satisfactory level of localization performance is required to ensure safe and reliable operations. 3D laser range finder (LRF)-based localization is a suitable approach in areas where GPS signal is not accesible or unreliable. During naviga...

In large-scale and sparse scenes, such as farmland, orchards, mines, and substations, 3D simultaneous localization and mapping are challenging matters that need to address issues such as maintaining reliable data association for scarce environmental information and reducing the computational complexity of global optimization for large-scale scenes....

Purpose Soft robotics, regarded as a new research branch of robotics, has generated increasing interests in this decade and has demonstrated its outperformance in addressing safety issues when cooperating with human beings. However, there is still lack of accurate close-loop control because of the difficulty in acquiring feedback information and a...

During autonomous navigation, environmental information and map noises at different locations may have dissimilar influence on a vehicle's localization process. This implies that the vehicle's localizability, i.e., the ability to localize itself in an environment using laser range finder (LRF) readings, varies over a given map. It is essential to t...