Cable Manipulator Research Articles

Wiring connector-terminated cables based on manipulation planning with collision-free EMD net

In this paper, we propose a manipulation planning method for cable wiring in the assembly of electric appliances etc. We address a scenario where a robot grasps a connector attached to the end of a cable and has to bring the connector to a socket. To accomplish this automatically, we propose a novel manipulation planning method. The method extends the Encode-Manipulate-Decode network (EMD net), which can predict shape changes of deformable objects and generate robot motion sequences for producing desired shape transitions. This enables us to find connector trajectories that avoid collision between the cable and the surrounding environment. We conducted experiments with several different cable lengths. We also introduce some functions required for real-world wiring, such as online cable shape modification. Experimental results show that the proposed method can achieve stable manipulation of real cables.

Manipulation Planning for Cable Shape Control

The control of deformable linear objects (DLOs) such as cables presents a significant challenge for robotic systems due to their unpredictable behavior during manipulation. This paper introduces a novel approach for cable shape control using dual robotic arms on a two–dimensional plane. A discrete point model is utilized for the cable, and a path generation algorithm is developed to define intermediate cable shapes, facilitating the transformation of the cable into the desired profile through a formulated optimization problem. The problem aims to minimize the discrepancy between the cable configuration and the targeted shape to ensure an accurate and stable deformation process. Moreover, a cable dynamic model is developed in which the manipulation approach is validated using this model. Additionally, the approach is tested in a simulation environment in which a framework of two manipulators grasps a cable. The results demonstrate the feasibility and accuracy of the proposed method, offering a promising direction for robotic manipulation of cables.

Manipulation Planning for Wiring Connector-Attached Cables Considering Linear Object’s Deformability

In this paper, we propose a method of manipulation planning for cable wiring. The method enables to take into account the deformation of cables while connector incorporation process. Using a physical simulation that predicts the shape of a cable based on the pose of both ends of the cable, we generate a connector moving path that avoids intereference between the cable and surrounding structures. We conducted experiments under several different environments and several different lengths of cables, and confirmed that actual cable manipulation can stably be achieved by using the proposed method.

Prediction of Cable Behavior Using Finite Element Analysis Results for Flexible Cables

In actual industrial sites, verifying the framework for cable manipulation is crucial. Therefore, it is necessary to simulate the deformation of the cable to predict its behavior accurately. By simulating the behavior in advance, it is possible to reduce the time and cost required for work. Although finite element analysis is used in various fields, the results may differ from the actual behavior depending on the method of defining the analysis model and analysis conditions. This paper aims to select appropriate indicators that can effectively cope with finite element analysis and experiments during cable winding work. We perform finite element analysis of the behavior of flexible cables and compare the analysis results with results from experiments. Despite some differences between the experimental and analysis outcomes, an indicator was developed through trial and error to align the two cases. Errors occurred during the experiments depending on the analysis and experimental conditions. To address this, weights were derived through optimization to update the cable analysis results. Additionally, deep learning was utilized to update the errors caused by material properties using the weights. This allowed for finite element analysis even when the exact physical properties of the material were unknown, ultimately improving the analysis performance.

Grasp Analysis for the Robot-Based Manipulation of Pre-Assembled Cables with Electrical Connectors

The mounting of pre-assembled cables with electrical connectors is mainly carried out manually in industry today. An exemplary application is the interconnection of battery modules. Automation of such assembly tasks offers the potential for increasing efficiency but requires the design of suitable gripper systems. This is challenging as the cable induces state-dependent forces and torques on the gripper system, which must be transmitted via the complex surface geometries of the plugs. Currently, the required grasp force cannot be determined in advance but only after prototypes have been manufactured and with elaborate physical experiments. To overcome these drawbacks, we present a methodology for the grasp analysis of pre-assembled cables with electrical connectors. The novelty of this approach is to combine a physics simulation for deformable linear objects with a contact model for non-planar grasping surfaces. The results indicate that the cable deformation significantly affects the required grasp force. In addition, each combination of contact surface and dynamic cable deformation results in an individual grasp force course. The methodology enables comparison of different electrical connectors and their grasping surfaces, as well as cables and their manipulation paths, efficiently and with little expert knowledge.

BILATERAL SHOULDER DISARTICULATION FOLLOWING HIGH VOLTAGE ELECTRIFICATION: CASE REPORT

The high voltage electrical burn is a rare but very serious incident involving the vital and functional prognosis. It generally occurs in young active subjects and in professional environments, especially in the context of work accidents. Tissue damage is immediately disastrous and requires multidisciplinary management. The recourse to amputation or bilateral disarticulation leads to a serious disability with a heavy socio-professional and psychological repercussion, hence the interest of prevention and awareness. We report the case of a 35 years old patient who suffered a high voltage electrification of both upper limbs during a false manipulation of high voltage cables.

Learning-based cable coupling effect modeling for robotic manipulation of heavy industrial cables

The robotic manipulation of a heavy industrial cable is challenging to model and control because of the high number of degrees of freedom and the rigid-flexible coupling dynamics. In this paper, we report the development of modeling the cable effect and control methodology for robotic cable manipulation. Our cable effect model is based on the 2D convolutional neural network, which is a deep learning-based method uses the effective cable representation method to achieve the accurate, generalizable, and efficient estimation of the cable coupling forces and torques. Practical problems such as the measurement limits and time efficiency are considered in our method for real applications. With these approaches, we are the first to solve the problem of dynamic payload effect caused by heavy industrial cables in experimental cases. The used control methodology combines the active disturbance rejection control framework with the sliding mode control method, which can acquire promising tracking performance. We integrate our cable effect model into the control scheme, and demonstrate it satisfies the high-quality robotic manipulation of heavy cables. The performance of the proposed method is assessed with both a simulated system and real robot system. The results show that our method can estimate the cable coupling effect with over 85% accuracy and accomplish manipulation with a positioning error less than 0.01 mm. This reveals that our method is promising for robotic manipulation of heavy industrial cables and can accomplish the challenging cable insertion task.

Offline-Online Learning of Deformation Model for Cable Manipulation With Graph Neural Networks

Manipulating deformable linear objects by robots has a wide range of applications, e.g., manufacturing and medical surgery. To complete such tasks, an accurate dynamics model for predicting the deformation is critical for robust control. In this work, we deal with this challenge by proposing a hybrid offline-online method to learn the dynamics of cables in a robust and data-efficient manner. In the offline phase, we adopt Graph Neural Network (GNN) to learn the deformation dynamics purely from the simulation data. Then a linear residual model is learned in real-time to bridge the sim-to-real gap. The learned model is then utilized as the dynamics constraint of a trust region based Model Predictive Controller (MPC) to calculate the optimal robot movements. The online learning and MPC run in a closed-loop manner to robustly accomplish the task. Finally, comparative results with existing methods are provided to quantitatively show the effectiveness and robustness.

The Design of a Lightweight Cable Aerial Manipulator with a CoG Compensation Mechanism for Construction Inspection Purposes

Conventionally, aerial manipulators, when used for inspection, use drone rotors to stabilize the center of gravity (CoG) shifts, which highly affects its performance. This paper discusses the development of a self-balancing lightweight cable aerial manipulator that can be used for construction inspection purposes. The design is based on a 3D-printed, three degrees of freedom (DoF), planar cable manipulator that is mounted on an extended platform below it as a counter-balance mechanism. The actuators control the manipulator links through a cable system, allowing them to be mounted at the system base to reduce the moving mass of the manipulator during operation. The counter-balance mechanism compensates for any shifts in the CoG of the system by actively sliding a counter-balance weight, mainly a battery, which powers the setup. This mechanism can be attached beneath an off-the-shelf quadrotor to solve the problem of CoG shifts. CoG shifts are due to the manipulator operation when a payload or inspection tool is attached to the end effector to perform a given task. For construction integrity inspection, the aerial manipulator must remain stable during the push or slide processes on both flat and curved surfaces while the non-destructive tests are carried out. To validate the effectiveness of the proposed design, an experimental setup was used, and comparisons were made between the compensated and uncompensated tilt angles of the aerial manipulator. Significant tilt angle reductions were observed with an average of 94.69% improvement, undergoing different manipulator motions during different operation scenarios, as a result of an active compensation of the CoG shift and lightweight design of the system, without sacrificing the functionality of the manipulator for the task.

Cable manipulation with a tactile-reactive gripper

Cables are complex, high-dimensional, and dynamic objects. Standard approaches to manipulate them often rely on conservative strategies that involve long series of very slow and incremental deformations, or various mechanical fixtures such as clamps, pins, or rings. We are interested in manipulating freely moving cables, in real time, with a pair of robotic grippers, and with no added mechanical constraints. The main contribution of this paper is a perception and control framework that moves in that direction, and uses real-time tactile feedback to accomplish the task of following a dangling cable. The approach relies on a vision-based tactile sensor, GelSight, that estimates the pose of the cable in the grip, and the friction forces during cable sliding. We achieve the behavior by combining two tactile-based controllers: (1) cable grip controller, where a PD controller combined with a leaky integrator regulates the gripping force to maintain the frictional sliding forces close to a suitable value; and (2) cable pose controller, where an linear–quadratic regulator controller based on a learned linear model of the cable sliding dynamics keeps the cable centered and aligned on the fingertips to prevent the cable from falling from the grip. This behavior is possible with the use of reactive gripper fitted with GelSight-based high-resolution tactile sensors. The robot can follow 1 m of cable in random configurations within two to three hand regrasps, adapting to cables of different materials and thicknesses. We demonstrate a robot grasping a headphone cable, sliding the fingers to the jack connector, and inserting it. To the best of the authors’ knowledge, this is the first implementation of real-time cable following without the aid of mechanical fixtures. Videos are available at http://gelsight.csail.mit.edu/cable/

Tethered Tool Manipulation Planning With Cable Maneuvering

In this letter, we present a planner for manipulating tethered tools using dual-armed robots. The planner generates robot motion sequences to maneuver a tool and its cable while avoiding robot-cable entanglements. Firstly, the planner generates an object manipulation motion sequence (OMMS) to handle the tool and place it in desired poses. Secondly, the planner examines the tool movement associated with the OMMS and computes candidate positions for a cable slider, to maneuver the tool cable and avoid collisions. Finally, the planner determines the optimal slider positions to avoid entanglements and generates a cable manipulation motion sequence (CMMS) to place the slider in these positions. The robot executes both the OMMS and CMMS to handle the tool and its cable to avoid entanglements and excess cable bending. Simulations and real-world experiments help validate the proposed method.

Investigation of the configuration of a parallel manipulator for additive manufacturing of solid structures

The last decade has seen an increase in publications on mechatronic systems of parallel structure with flexible connections. Such manipulators are used in the field of videography of sports events and in crane structures for special purposes. The paper proposes and studies the question of the use of a parallel structure manipulator with flexible connections to create a complex of additive manufacturing of building structures. The basic structural schemes of kinematics of cable parallel manipulators are considered. The solutions of direct and inverse kinematics problems of parallel structures suitable for building additive systems are considered. The developed mathematical model of the kinematics of cable manipulators makes it possible to conduct further research on the implementation of the control system in real-time mode.

Robotic Manipulation Planning for Shaping Deformable Linear Objects WithEnvironmental Contacts

Humans use contacts in the environment to modify the shape of deformable objects. Yet, few papers have studied the use of contacts in robotic manipulation. In this letter, we investigate the problem of robotic manipulation of cables with environmental contacts. Instead of avoiding contacts, we propose a framework that allows the robot to use them for shaping the cable. We introduce an index to quantify the contact mobility of a cable with a circular contact. Based on this index, we present a planner to plan robot motions. The planner is aided by a vision-based contact detector. The framework is validated with robot experiments on different desired cable configurations.

Dual-arm Cable Manipulation by Whole-body Control of a Humanoid Robot

Dual-arm Cable Manipulation by Whole-body Control of a Humanoid Robot

Dynamical Analysis of a Cable Manipulator Using Multibody Approaches

This paper deals with the creation of a computational model of a particular cable manipulator composed of a rigid manipulator with three degrees of freedom and a platform driven by four fibers. Each fiber is led over a pulley and is driven by a linear motor, which can be controlled. The multibody dynamics approach is a suitable way in order to create the manipulator model. The most common cable modelling techniques are summarized in this paper and then the computational model of the cable manipulator QuadroSphere is created using MSC.Adams software. The computational model verification is done using the modal analysis of linearized model and the experimental modal analysis on the real set up. Further results of various numerical simulations are presented and their utilization is discussed.

Analysis of planar shear deformable beam using rotation field curvature formulation

In recent years, research on space debris removal technique has received wide attention in aerospace field. Many novel concepts on active flexible debris remover have been proposed, such as flexible flying net, tethered cable manipulator. In view with the high flexibility and large deformation of this kind of structure, the implementation of attitude control is challenging. An accurate dynamic model of highly flexible structure is important and needed. The beam element is the most common element adopted in flexible remover models. So, in this investigation, a rotation field-based curvature shear deformable beam using absolute nodal coordinate formulation (ANCF) (named RB-curvature ANCF beam) is proposed and its geometrically nonlinear characteristic under large deformation motion is studied. Curvature is first derived through planar rotation transformation matrix between the reference frame and current tangent frame of beam centerline, and written as an arc-length derivative of the orientation angle of the tangent vector. Using the geometrically exact beam theory, the strain energy is expressed as an uncoupled form, and the new curvature is adopted to formulate bending energy. Based on the ANCF, the dynamic equation of beam is established, where mass and external force matrices are constant. In order to validate the performance of proposed beam element, other two types of beams are introduced as the comparative models. One is the classical ANCF fully parameterized shear deformable beam derived by continuum mechanics theory, and the other is position field-based curvature ANCF shear deformable beam (named PBcurvature ANCF beam). The PB-curvature model is evaluated by differentiating unit tangent vector of beam centerline with respect to its arc length quoted from differential geometry theory. A series of static analysis, eigenfrequency tests and dynamic analysis are implemented to examine the performance of the proposed element. In static analysis, both small and non-small deformation cases show that the proposed RB-curvature ANCF beam achieves the faster speed, higher precision and good agreement with analytical solution in the case of cantilever beam subjected to a concentrated tip force, which is compared with other two beam models. The eigenfrequency analysis validates RB-curvature ANCF beam in a simply supported beam case that converges to its analytical solution. Meanwhile, the mode shapes of the proposed ANCF beam could be correctly corresponded to vibration state of element with respect to each different eigenfrequency. In the dynamics test, a flexible pendulum case is used and simulation results show that the proposed RB-curvature ANCF beam accords well with ANSYS BEAM3, classical ANCF shear beam and PB-curvature ANCF beam in vertical displacements of tip point and middle point. Since deformation modes are uncoupled in the cross section of proposed beam element, its shear strain is achieved with much better convergence in the case of lower elastic modulus, and shear locking is significantly alleviated, compared with classical ANCF beam. Therefore, RB-curvature ANCF shear deformable beam element proposed in this paper is able to describe accurately geometric nonlinearity in large deformation problem, and can be a potential candidate in the modeling of flexible/rigid-flexible mechanisms.

A Three-Dimensional-Printed Home-Based Flexible Nasopharyngeal Explorer With Diamond Cuts1

A Three-Dimensional-Printed Home-Based Flexible Nasopharyngeal Explorer With Diamond Cuts1

Adaptive Controller for ROV Based on Hybrid Theory

In order to deal with the model uncertainties of ROV (remotely operated vehicles) caused by current disturbances, umbilical cable and robotic manipulators, an adaptive backstepping controller and an adaptive PD controller are applied to control the ROV. The adaptive backstepping controller is used to control the horizontal motion, and the adaptive PD controller is applied to control the Vertical motion. Finally, the method is verified effective by the computer simulation.

An Overview of the Development for Cable-Driven Parallel Manipulator

In the last two decades, cable-driven parallel robots have attracted a lot of attention in robot community as a hot topic of robot research. In this paper, the development of the cable-driven parallel manipulator is first introduced in general. Second, the latest advance in theory and applications of cable-driven parallel manipulator is presented in detail, especially some notable implementations. Finally, an other probable application foresight with this cable manipulator is proposed and discussed.

21st Century Kinematics: Synthesis, Compliance, and Tensegrity

As we move into the second decade of the 21st century, we can identify three research trends that we can expect to persist into the future. They are the analysis and synthesis of (i) spatial mechanisms and robotic systems, (ii) compliant linkage systems, and (iii) tensegrity and cable-driven systems. In each case, we find that researchers are formulating and solving polynomial systems of total degrees that dwarf those associated with major kinematics problems of the previous century.