Follow-the-leader motion strategy for multi-section continuum robots based on differential evolution algorithm

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
GuoHua Gao ◽  
Pengyu Wang ◽  
Hao Wang
Keyword(s):  
Differential Evolution ◽  
Kinematic Model ◽  
Differential Evolution Algorithm ◽  
Open Loop ◽  
Continuum Robots ◽  
Content Type ◽  
Loop Control ◽  
Continuum Robot ◽  
Motion Strategy ◽  
The Continuum

Purpose The purpose of this paper is to present a follow-the-leader motion strategy for multi-section continuum robots, which aims to make the robot have the motion ability in a confined environment and avoid a collision. Design/methodology/approach First, the mechanical design of a multi-section continuum robot is introduced and the forward kinematic model is built. After that, the follow-the-leader motion strategy is proposed and the differential evolution (DE) algorithm for calculating optimal posture parameters is presented. Then simulations and experiments are carried out on a series of predefined paths to analyze the performance of the follow-the-leader motion. Findings The follow-the-leader motion can be well performed on the continuum robots this study proposes in this research. The experimental results show that the deviation from the path is less than 9.7% and the tip error is no more than 15.6%. Research limitations/implications Currently, the follow-the-leader motion is affected by the following factors such as gravity and continuum robot design. Furthermore, the position error is not compensated under open-loop control. In future work, this paper will improve the accuracy of the robot and introduce a closed-loop control strategy to improve the motion accuracy. Originality/value The main contribution of this paper is to present an algorithm to generate follow-the-leader motion of the continuum robot based on DE. This method is suitable for solving new arrangements in the process of following a nonlinear path. Then, it is expected to promote the engineering application of the continuum robot.

An Analytical Tension Model for Continuum Robots with n Generally Positioned Tendons

2019 ◽  
Vol 04 (03n04) ◽  
pp. 1942003
Author(s):  
Mohsen Moradi Dalvand ◽  
Saeid Nahavandi ◽  
Robert D. Howe
Keyword(s):  
Stereo Vision ◽  
Control Algorithm ◽  
Open Loop ◽  
Open Loop Control ◽  
Continuum Robots ◽  
Loop Control ◽  
Proposed Model ◽  
Continuum Robot ◽  
Tension Loading ◽  
Tendon Compliance

The estimation of tension loads in multi-tendon continuum robots or catheters plays an important role not only in the design process but also in the control algorithm to avoid slack. An analytical tension loading model is developed that, for any given beam configuration within the workspace, calculates tendon tensions in [Formula: see text]-tendon continuum robots with general tendon positioning. The model accounts for the bending and axial compliance of the manipulator as well as tendon compliance. A 6-tendon continuum robot integrated with a stereo vision-based 3D reconstruction system is utilized to experimentally validate the proposed analytical model in open-loop control architecture. The proposed model demonstrates around 95% accuracy in estimating tendon tensions in a continuum robot with general tendon positioning and axial stretch in its tendons for all of the trials and experiments.

scholarly journals Task space-based orientability analysis and optimization of a wire-driven continuum robot

2019 ◽  
Vol 233 (23-24) ◽  
pp. 7658-7668
Author(s):  
Cong Wang ◽  
Shineng Geng ◽  
David T Branson ◽  
Chenghao Yang ◽  
Jian S Dai ◽  
...  
Keyword(s):  
Particle Swarm Optimization Algorithm ◽  
Kinematic Model ◽  
Task Space ◽  
Continuum Robots ◽  
Swarm Optimization ◽  
The Monte Carlo Method ◽  
Continuum Robot ◽  
Two Indices ◽  
Joint Length ◽  
The Continuum

Compared to traditional rigid robots, continuum robots have intrinsic compliance and therefore behave dexterously when performing tasks in restricted environments. Although there have been many researches on the design and application of continuum robots, a theoretical investigation of their dexterity is still lacking. In this paper, a two-joint wire-driven continuum robot is utilized to demonstrate dexterity by introducing the concept of orientability taking into account two indices, the accessible ratio and angle of the robot, when its tip reaches a certain task space inside the workspace. Based on the kinematic model, the accessible ratio and angle of the continuum robot are calculated using the Monte-Carlo method. From this, the influence of individual joint lengths on the proposed orientability indices and the optimal joint length are then investigated via an improved particle swarm optimization algorithm. Finally, the presented methods were validated through experiments showing that the use of optimal joint length can increase the accessible ratio and reduce the minimum accessible angle by more than 10° in the task space.

Development of a Multi-Cable-Driven Continuum Robot Controlled by Parallel Platforms

2020 ◽  
pp. 1-11 ◽  
Author(s):  
Xinbo Chen ◽  
Jiantao Yao ◽  
Tong Li ◽  
Haili Li ◽  
Pan Zhou ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Load Capacity ◽  
Continuum Robots ◽  
Position Accuracy ◽  
Continuum Robot ◽  
In Series ◽  
Kinematic Models ◽  
Parallel Platform ◽  
Tube Structure ◽  
The Continuum

Abstract Cable-driven continuum robots exhibit excellent capabilities in the unstructured environment due to their inherent compliance and dexterity. To improve the reliability and load capacity of continuum robots, increasing the number of cables is often used in the control of continuum robots. However, the number of actuators will increase with the cables. To tackle this challenge, this work proposes a method for increasing the number of cables without increasing actuators in a continuum robot through parallel platforms. The parallel platforms are used to control all the cables in the continuum robot, and can be separated from the continuum robot to enable the remote drive of a manipulation arm by using the cable-tube structure. The manipulation arm is composed of several independent bending modules in series, which can be configured freely according to the demand of degrees of freedom. Further, each bending module is controlled independently by a parallel platform, which can avoid the mutual interference between the cables of one bending module and another one, improve the position accuracy and simplify the control difficulty of the manipulation arm. To evaluate the proposed method, this work develops a prototype of six-cable-driven continuum robot controlled by 3RPS parallel platforms, and presents some basic kinematic models to describe its function, and then an experimental work characterizing its performance. Experimental results illustrated the importance of increasing the number of cables, the rationality of kinematic models of the continuum robot, and the feasibility of controlling multiple cables by a parallel platform.

Study on multi-section continuum robot wire-tension feedback control and load manipulability

2020 ◽  
Vol 47 (6) ◽  
pp. 837-845
Author(s):  
Azamat Nurlanovich Yeshmukhametov ◽  
Koichi Koganezawa ◽  
Zholdas Buribayev ◽  
Yedilkhan Amirgaliyev ◽  
Yoshio Yamamoto
Keyword(s):  
Control Method ◽  
Tension Control ◽  
Estimation Model ◽  
Content Type ◽  
Wire Tension ◽  
Payload Capacity ◽  
Continuum Robot ◽  
Continuum Manipulators ◽  
And Control ◽  
The Continuum

Purpose The purpose of this paper is to present a novel hybrid pre-tension mechanism for continuum manipulators to prevent wire slack and improve continuum robot payload capacity, as well as to present a new method to control continuum manipulators’ shape. Design/methodology/approach This research explains the hardware design of a hybrid pre-tension mechanism device and proposes a mathematic formulation wire-tension based on robot design. Also, the wire-tension control method and payload estimation model would be discussed. Findings Wire-tension is directly related to the continuum manipulators’ rigidity and accuracy. However, in the case of robot motion, wires lose their tension and such an issue leads to the inaccuracy and twist deformation. Therefore, the proposed design assists in preventing any wire slack and derailing the problem of the wires. Originality/value The novelty of this research is proposed pre-tension mechanism device design and control schematics. Proposed pre-tension mechanism designed to maintain up to eight wires simultaneously.

scholarly journals Micrometer Positioning Accuracy With a Planar Parallel Continuum Robot

2021 ◽  
Vol 8 ◽  
Author(s):  
Benjamin Mauzé ◽  
Guillaume J. Laurent ◽  
Redwan Dahmouche ◽  
Cédric Clévy
Keyword(s):  
Kinematic Model ◽  
High Accuracy ◽  
Circular Path ◽  
Continuum Robots ◽  
Continuum Robot ◽  
Good Potential ◽  
Proper Estimation ◽  
Articulated Robots ◽  
Automatic Positioning ◽  
Influential Parameters

Parallel Continuum Robots (PCR) have several advantages over classical articulated robots, notably a large workspace, miniaturization capabilities and safe human-robot interactions. However, their low accuracy is still a serious drawback. Indeed, several conditions have to be met for PCR to reach a high accuracy, namely: a repeatable mechanical structure, a correct kinematic model, and a proper estimation of the model’s parameters. In this article, we propose a methodology that allows reaching a micrometer accuracy with a PCR. This approach emphasizes the importance of using a repeatable continuum mechanism, identifying the most influential parameters of an accurate kinematic model of the robot and precisely measuring them. The experimental results show that the proposed approach allows to reach an accuracy of 3.3 µm in position and 0.5 mrad in orientation over a 10 mm long circular path. These results push the current limits of PCR accuracy and make them good potential candidates for high accuracy automatic positioning tasks.

Optimal stable gait for nonlinear uncertain humanoid robot using central force optimization algorithm

2019 ◽  
Vol 36 (2) ◽  
pp. 599-621 ◽  
Author(s):  
Tran Thien Huan ◽  
Ho Pham Huy Anh
Keyword(s):  
Differential Evolution ◽  
Humanoid Robot ◽  
Differential Evolution Algorithm ◽  
Humanoid Robots ◽  
Central Force ◽  
Content Type ◽  
Force Optimization ◽  
Gait Parameters ◽  
Stable Gait ◽  
Central Force Optimization

Purpose The purpose of this paper is to design a novel optimized biped robot gait generator which plays an important role in helping the robot to move forward stably. Based on a mathematical point of view, the gait design problem is investigated as a constrained optimum problem. Then the task to be solved is closely related to the evolutionary calculation technique. Design/methodology/approach Based on this fact, this paper proposes a new way to optimize the biped gait design for humanoid robots that allows stable stepping with preset foot-lifting magnitude. The newly proposed central force optimization (CFO) algorithm is used to optimize the biped gait parameters to help a nonlinear uncertain humanoid robot walk robustly and steadily. The efficiency of the proposed method is compared with the genetic algorithm, particle swarm optimization and improved differential evolution algorithm (modified differential evolution). Findings The simulated and experimental results carried out on the small-sized nonlinear uncertain humanoid robot clearly demonstrate that the novel algorithm offers an efficient and stable gait for humanoid robots with respect to accurate preset foot-lifting magnitude. Originality/value This paper proposes a new algorithm based on four key gait parameters that enable dynamic equilibrium in stable walking for nonlinear uncertain humanoid robots of which gait parameters are initiatively optimized with CFO algorithm.

An inspection continuum robot with tactile sensor based on electrical impedance tomography for exploration and navigation in unknown environment

2019 ◽  
Vol 47 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Yaming Wang ◽  
Feng Ju ◽  
Yahui Yun ◽  
Jiafeng Yao ◽  
Yaoyao Wang ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Aircraft Engine ◽  
Tactile Sensor ◽  
Average Error ◽  
Impedance Tomography ◽  
Content Type ◽  
Inspection Robot ◽  
Continuum Robot ◽  
The Continuum

Purpose This paper aims to introduce an aircraft engine inspection robot (AEIR) which can go in the internal of the aircraft engine without collision and detect damage for engine blades. Design/methodology/approach To obtain the position and pose information of the blades inside the engine, a novel tactile sensor based on electrical impedance tomography (EIT) is developed, which could provide location and direction information when it contacts with an unknown object. In addition, to navigate the continuum robot, a control method is proposed to control the continuum robot, which can control the continuum robot to move along the pre-planned path and reduce the deviation from the planned path. Findings Experiment results show that the average error of contact location measurement of the tactile sensor is 0.8 mm. The average error relative to the size (diameter of 18 mm) of the sensor is 4.4%. The continuum robot can successfully reach the target position through a gap of 30 mm and realize the spatial positioning of blades. The validity of the AEIR for engine internal blade detection is verified. Originality/value The aero-engine inspection robot developed in this paper can replace human to detect engine blades and complete different detection tasks with different kinds of sensors.

scholarly journals Kinematic Model and Real-Time Path Generator for a Wire-Driven Surgical Robot Arm with Articulated Joint Structure

2019 ◽  
Vol 9 (19) ◽  
pp. 4114 ◽  
Author(s):  
Jin ◽  
Lee ◽  
Lee ◽  
Han
Keyword(s):  
Kinematic Model ◽  
Joint Space ◽  
Open Loop ◽  
Surgical Robot ◽  
Path Generation ◽  
Robot Arm ◽  
Open Loop Control ◽  
Loop Control ◽  
Joint Structure ◽  
Forward Kinematic

This paper presents a forward kinematic model of a wire-driven surgical robot arm with an articulated joint structure and path generation algorithms with solutions of inverse kinematics. The proposed methods were applied to a wire-driven surgical robot for single-port surgery. This robot has a snake-like robotic arm with double segments to fit the working space in a single port and a joint structure to secure stiffness. The accuracy of the model is highly important because small surgical robot arms are usually controlled by open-loop control. A curvature model is widely used to describe and control a continuum robotic body. However, the model is quite different from a continuum robotic arm with a joint structure and can lead to slack of the driving wires or decreased stiffness of the joints. An accurate forward kinematic model was derived to fit the actual hardware structure via the frame transformation method. An inverse kinematic model from the joint space to the wire-length space was determined from an asymmetric model for the joint structure as opposed to a symmetric curvature model. The path generation algorithm has to generate a command to send to each actuator in open-loop control. Two real-time path generation algorithms that solve for inverse kinematics from the task space to the joint space were designed and compared using simulations and experiments. One of the algorithms is an optimization method with sequential quadratic programming (SQP), and the other uses differential kinematics with a PID (Proportional-Integral-Derivative) control algorithm. The strengths and weaknesses of each algorithm are discussed.

Drive optimization of a pulsatile total artificial heart

2014 ◽  
Vol 33 (3) ◽  
pp. 941-952
Author(s):  
André Pohlmann ◽  
Kay Hameyer
Keyword(s):  
Cardiovascular Diseases ◽  
Differential Evolution ◽  
Cost Function ◽  
Human Body ◽  
Differential Evolution Algorithm ◽  
Optimization Methods ◽  
Parameter Variation ◽  
Optimization Process ◽  
Total Artificial Heart ◽  
Content Type

Purpose – Total artificial hearts (TAHs) are required for the treatment of cardiovascular diseases. In order to replace the native heart a TAH must provide a sufficient perfusion of the human body, prevent blood damage and meet the implantation constraints. Until today there is no TAH on the market which meets all constraints. So the purpose of this paper is to design a drive in such a way that the operated TAH meets all predefined constraints. Design/methodology/approach – The drive is designed in terms of weight and electric losses. In setting up a cost function containing those constraints, the drive design can be included in a optimization process. When reaching the global minimum of the cost function the optimum drive design is found. In this paper the optimization methods manual parameter variation and differential evolution are applied. Findings – At the end of the optimization process the drive's weight amounts to 460 g and its mean losses sum up to 10 W. This design meets all predefined constraints. Further it is proposed to start the optimization process with a parameter variation to reduce the amount of optimization parameters for the time consuming differential evolution algorithm. Practical implications – This TAH has the potential to provide a therapy for all patients suffering from cardiovascular diseases as it is independent of donor organs. Originality/value – The optimization-based design process yields an optimum drive for a TAH in terms of weight and electrical losses. In this way a TAH is developed which meets all implantation constraints and provides sufficient perfusion of the human body at the same time.

Jacobian Matrix of a Novel Continuum Robot for Search and Rescue

2013 ◽  
Vol 303-306 ◽  
pp. 1695-1701 ◽  
Author(s):  
Guang Zhu Meng ◽  
Ling Yu Sun ◽  
Ping Peng ◽  
Xian Chun Meng ◽  
Hong Mei Wang ◽  
...  
Keyword(s):  
Jacobian Matrix ◽  
Kinematic Model ◽  
Search And Rescue ◽  
Chain Rule ◽  
Continuum Robots ◽  
Actuation System ◽  
Continuum Robot ◽  
Forward Kinematic

In this paper, a novel continuum robot for search and rescue is presented. A forward kinematic model is derived by product of exponentials formula, compare with conventional D-H method, this method is concise and simplicity. Finally, based on the differential kinematics using the chain rule, the overall Jacobian of the robot is established. This approach can be generally applied to various continuum robots, regardless of the specific actuation system used.

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