scholarly journals Novel Design of a Soft Lightweight Pneumatic Continuum Robot Arm with Decoupled Variable Stiffness and Positioning

Soft Robotics ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 54-70 ◽  
Author(s):  
Maria Elena Giannaccini ◽  
Chaoqun Xiang ◽  
Adham Atyabi ◽  
Theo Theodoridis ◽  
Samia Nefti-Meziani ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Robot Arm ◽  
Continuum Robot ◽  
Novel Design

scholarly journals Novel Design and Position Control Strategy of a Soft Robot Arm

Robotics ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 72 ◽  
Author(s):  
Alaa Al-Ibadi ◽  
Samia Nefti-Meziani ◽  
Steve Davis ◽  
Theo Theodoridis
Keyword(s):  
Position Control ◽  
Control Strategies ◽  
Tensile Force ◽  
Compressive Force ◽  
Soft Robot ◽  
Robot Arm ◽  
Bending Actuator ◽  
Muscle Actuators ◽  
Novel Design ◽  
Bending Behaviour

This article presents a novel design of a continuum arm, which has the ability to extend and bend efficiently. Numerous designs and experiments have been done to different dimensions on both types of McKibben pneumatic muscle actuators (PMA) in order to study their performances. The contraction and extension behaviour have been illustrated with single contractor actuators and single extensor actuators, respectively. The tensile force for the contractor actuator and the compressive force for the extensor PMA are thoroughly explained and compared. Furthermore, the bending behaviour has been explained for a single extensor PMA, multi extensor actuators and multi contractor actuators. A two-section continuum arm has been implemented from both types of actuators to achieve multiple operations. Then, a novel construction is proposed to achieve efficient bending behaviour of a single contraction PMA. This novel design of a bending-actuator has been used to modify the presented continuum arm. Two different position control strategies are presented, arising from the results of the modified soft robot arm experiment. A cascaded position control is applied to control the position of the end effector of the soft arm at no load by efficiently controlling the pressure of all the actuators in the continuum arm. A new algorithm is then proposed by distributing the x, y and z-axis to the actuators and applying an effective closed-loop position control to the proposed arm at different load conditions.

scholarly journals Development of Continuum Robot Arm and Gripper for Harvesting Cherry Tomatoes

2019 ◽  
Author(s):  
Azamat Yeshmukhametov ◽  
Koichi Koganezawa ◽  
Zholdas Buribayev ◽  
Yedilkhan Amirgaliyev ◽  
Yoshio Yamamoto
Keyword(s):  
Machine Learning ◽  
Recognition System ◽  
Stem Cutting ◽  
Robot Arm ◽  
Design And Development ◽  
Challenging Issue ◽  
Continuum Robot ◽  
Unstructured Environment ◽  
Backbone Structure ◽  
Cherry Tomatoes

Designing and development of agricultural robot is always a challenging issue, because of robot intends to work an unstructured environment and at the same time, it should be safe for the surrounded plants. Therefore, traditional robots cannot meet the high demands of modern challenges, such as working in confined and unstructured workspaces. Based on current issues, we developed a new tomato harvesting wire-driven discrete continuum robot arm with a flexible backbone structure for working in confined and extremely constrained spaces. Moreover, we optimized a tomato detaching process by using newly designed gripper with passive stem cutting function. Moreover, by designing the robot we also developed ripe tomato recognition by using machine learning. This paper explains the proposed continuum robot structure, gripper design, and development of tomato recognition system.

Cadaveric feasibility study of a teleoperated parallel continuum robot with variable stiffness for transoral surgery

2020 ◽  
Vol 58 (9) ◽  
pp. 2063-2069
Author(s):  
Changsheng Li ◽  
Xiaoyi Gu ◽  
Xiao Xiao ◽  
Chwee Ming Lim ◽  
Hongliang Ren
Keyword(s):  
Feasibility Study ◽  
Variable Stiffness ◽  
Transoral Surgery ◽  
Continuum Robot

scholarly journals The Stiffness Calculation and Optimization for the Variable Stiffness Load Torque Simulation System

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Zhe Ji ◽  
Xiaoxian Yao ◽  
Zuobao Liang
Keyword(s):  
Wind Tunnel ◽  
Calculation Method ◽  
Tracking Error ◽  
Wind Tunnel Test ◽  
Variable Stiffness ◽  
Simulation System ◽  
Load Torque ◽  
Loading System ◽  
Optimal Set ◽  
Novel Design

This paper presents a novel design for a variable stiffness load torque simulation system. The system is applied to the load torque on a rudder in a real-time hardware-in-the-loop system (HILS). Compared with the traditional loading method, in which unavoidable additional torque exists, the variable stiffness loading system employs a “first decomposed and then coupled” approach to output the load torque and to significantly reduce the additional torque. Based on experimental data obtained from a wind tunnel test, a calculation method is proposed to determine the loading parameters of the variable stiffness loading system. Since the load stiffness is related to a variety of factors, the stiffness values obtained from wind tunnel test data, such as the fixed Mach number and the rudder deflection angle, are not definite values. By analyzing the influencing factors of the loading parameters, an optimal set of load stiffness is obtained using an optimization algorithm, and exact tracking of the load torque is achieved. Using the calculation method to obtain a loading torque for the rudder as an example, the torque tracking error is less than 0.05 Nm. The simulation results indicate that the proposed calculation method for variable stiffness loading is effective.

scholarly journals Conceptual mechanical design of antagonistic variable stiffness joint based on equivalent quadratic torsion spring

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094129
Author(s):  
Jishu Guo
Keyword(s):  
Degrees Of Freedom ◽  
Modular Design ◽  
Angular Displacement ◽  
Variable Stiffness ◽  
Human Robot Interaction ◽  
Design Calculation ◽  
Robot Arm ◽  
Compact Structure ◽  
Torsion Spring ◽  
Stiffness Characteristics

The variable stiffness joint is a kind of flexible actuator with variable stiffness characteristics suitable for physical human–robot interaction applications. In the existing variable stiffness joints, the antagonistic variable stiffness joint has the advantages of simple implementation of variable stiffness mechanism and easy modular design of the nonlinear elastic element. The variable stiffness characteristics of antagonistic variable stiffness joints are realized by the antagonistic actuation of two nonlinear springs. A novel design scheme of the equivalent nonlinear torsion spring with compact structure, large angular displacement range, and desired stiffness characteristics is presented in this article. The design calculation for the equivalent quadratic torsion spring is given as an example, and the actuation characteristics of the antagonistic variable stiffness joint based on the equivalent quadratic torsion spring are illustrated. Based on the design idea of constructing the antagonistic variable stiffness joint with compact structure and high compliance, as well as the different design requirements of the joints at different positions of the multi–degrees of freedom robot arm, nine types of mechanical schemes of antagonistic variable stiffness joint with the open design concept are proposed in this article. Finally, the conceptual joint configuration schemes of the robot arm based on the antagonistic variable stiffness joint show the application scheme of the designed antagonistic variable stiffness joint in the multi–degrees of freedom robot.

A Novel Continuum Robot Using Twin-Pivot Compliant Joints: Design, Modeling, and Validation

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Xin Dong ◽  
Mark Raffles ◽  
Salvador Cobos-Guzman ◽  
Dragos Axinte ◽  
James Kell
Keyword(s):  
Kinematic Analysis ◽  
Joint Construction ◽  
Wide Range ◽  
Continuum Robot ◽  
Adequate Accuracy ◽  
Compliant Joint ◽  
Section Design ◽  
Twisting Angle ◽  
Accuracy And Repeatability ◽  
Novel Design

A twisting problem is identified from the central located flexible backbone continuum robot. Regarding this problem, a design solution is required to mechanically minimize this twisting angle along the backbone. Further, the error caused by the kinematic assumption of previous works is identified as well, which requires a kinematic solution to minimize. The scope of this paper is to introduce, describe and teste a novel design of continuum robot which has a twin-pivot compliant joint construction that minimizes the twisting around its axis. A kinematics model is introduced which can be applied to a wide range of twin-pivot construction with two pairs of cables per section design. And according to this model, the approach for minimising the kinematic error is developed. Furthermore, based on the geometry and material property of compliant joint, the work volumes for single/three-section continuum robot are presented, respectively. The kinematic analysis has been verified by a three-section prototype of continuum robot and adequate accuracy and repeatability tests carried out. And in the test, the system generates relatively small twisting angles when a range of end loads is applied at the end of the arm. Utilising the concept presented in this paper, it is possible to develop a continuum robot which can minimize the twisting angle and be accurately controlled. In this paper, a novel design of continuum robot which has a twin-pivot compliant joint construction that minimizes the twisting around its axis is introduced, described and tested. A kinematics model is introduced which can be applied to a wide range of twin-pivot construction with two pairs of cables per section design. Furthermore, based on the geometry and material property of compliant joint, the work volumes for single/three-section continuum robot are presented, respectively. Finally, the kinematic analysis has been verified by a three-section prototype of continuum and adequate accuracy and repeatability tests carried out.

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