Methodology to Identify and Analyze Optimal Cable Configurations in the Design of Cable-Driven Serial Manipulators

2013 ◽  
Author(s):  
Joshua T. Bryson ◽  
Sunil K. Agrawal
Keyword(s):  
Range Of Motion ◽  
Mechanism Design ◽  
Critical Parameters ◽  
Robot Design ◽  
Serial Manipulators ◽  
General Terms ◽  
Placement And Routing ◽  
Robot Leg

The choice of cable placement and routing for a cable-driven serial manipulator has profound effects on the operational workspace of the mechanism. Poor choices in cable attachment can hamper or preclude the ability of the mechanism to perform a desired task, while a clever configuration might allow for an expanded workspace and kinematic redundancies, providing additional capability and flexibility. This paper outlines a methodology to identify and analyze optimal cable configurations for a serial manipulator which maximize operational workspace subject to mechanism design and configuration constraints. This process is first described in general terms for a generic 2-link robot and then applied to an illustrative example of a cable-driven robot leg. The methodology is used to determine the placement and routing of the cables to achieve the desired range of motion, as well as highlight the critical parameters within the cable configuration and identify possible areas of improvement in the overall robot design.

Analysis of Optimal Cable Configurations in the Design of a 3-DOF Cable-Driven Robot Leg

2014 ◽  
Author(s):  
Joshua T. Bryson ◽  
Sunil K. Agrawal
Keyword(s):  
Range Of Motion ◽  
Degrees Of Freedom ◽  
Serial Robot ◽  
Placement And Routing ◽  
Robot Leg

The operational workspace of a cable-driven serial robot is largely dictated by the choice of cable placement and routing. As robot complexity increases with additional cables and degrees of freedom, the problem of designing a cable architecture can quickly become challenging. This paper builds upon a previously described methodology to identify and analyze optimal cable configurations, expanding the approach to a 3-DoF robot leg driven by four cables. The methodology is used to analyze configuration trends in the routing and placement of the cables which achieve the desired range of motion for the robot. The results of the analysis are used to inform the design of a cable architecture which is shown to be capable of controlling the robot through the desired task.

Addition of Springs and its Impact on Cable-Driven Serial Manipulators

2014 ◽  
Author(s):  
Qingjuan Duan ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Range Of Motion ◽  
Performance Characteristics ◽  
Serial Manipulators ◽  
Placement And Routing ◽  
Multi Body

Serial multi-body systems can be driven by cables routed through the links to achieve the desired range of motion. Placement and routing of the cables alter the performance characteristics of the manipulator. There are possible applications for such mechanisms where low moving inertia is required. One of the challenges in the design of cable-driven mechanisms is to keep cables in tension during the motion. In this article, the addition of springs and its impact on workspace is investigated. A 2-link cable-driven robot is used to illustrate changes in Wrench Feasible Workspace (WFW) as springs are added between the serial manipulator and the ground or between the links.

Mechanism Design and Simulation of the ULTRA Spine: A Tensegrity Robot

2015 ◽  
Author(s):  
Andrew P. Sabelhaus ◽  
Hao Ji ◽  
Patrick Hylton ◽  
Yakshu Madaan ◽  
ChanWoo Yang ◽  
...  
Keyword(s):  
Mechanism Design ◽  
Design Process ◽  
Inverse Kinematics ◽  
Gear Ratio ◽  
Forward Kinematics ◽  
Robot Design ◽  
Link Structure ◽  
Iterative Design ◽  
Quadruped Robots ◽  
Ongoing Effort

The Underactuated Lightweight Tensegrity Robotic Assistive Spine (ULTRA Spine) project is an ongoing effort to create a compliant, cable-driven, 3-degree-of-freedom, underactuated tensegrity core for quadruped robots. This work presents simulations and preliminary mechanism designs of that robot. Design goals and the iterative design process for an ULTRA Spine prototype are discussed. Inverse kinematics simulations are used to develop engineering characteristics for the robot, and forward kinematics simulations are used to verify these parameters. Then, multiple novel mechanism designs are presented that address challenges for this structure, in the context of design for prototyping and assembly. These include the spine robot’s multiple-gear-ratio actuators, spine link structure, spine link assembly locks, and the multiple-spring cable compliance system.

Tension-Efficient Cable-Driven Robot Design Using Particle Swarm Optimization

2015 ◽  
Author(s):  
Joshua T. Bryson ◽  
Sunil K. Agrawal
Keyword(s):  
Particle Swarm Optimization ◽  
Stochastic Optimization ◽  
Optimization Problems ◽  
Particle Swarm ◽  
Robot Design ◽  
Optimization Approach ◽  
Swarm Optimization ◽  
Robot Leg ◽  
Optimization Methodology ◽  
Specific Implementation

Cable-driven robots have advantages which make them attractive solutions for a variety of tasks, however, the unidirectional nature of cable actuators complicates the design and often results in multiply redundant cable architectures which increase cost and robot complexity. This paper presents a stochastic optimization approach to the problem of designing a cable routing for a cable-driven manipulator to provide the desired robot workspace while minimizing the cable tensions required to perform a desired task. Two cable routing design variants are developed for a robot leg through the application of a stochastic optimization methodology called Particle Swarm Optimization. The PSO methodology is summarized, followed by a description of the specific implementation of the methodology to the particular problem of optimizing the cable routing of a robot leg. An objective function is developed to capture all pertinent design criteria in a quantitative evaluation of each particular set of cable parameters. Finally, a description of the PSO execution is presented and the results of the two optimization problems are presented and discussed.

Optimization and analysis of a redundant 4R spherical wrist mechanism for a shoulder exoskeleton

Robotica ◽  
2014 ◽  
Vol 32 (8) ◽  
pp. 1191-1211 ◽  
Author(s):  
Ho Shing Lo ◽  
Shengquan Xie
Keyword(s):  
Genetic Algorithm ◽  
Range Of Motion ◽  
Mechanism Design ◽  
Condition Number ◽  
Optimal Operating ◽  
End Effector ◽  
Singular Configurations ◽  
The Past ◽  
Workspace Analysis ◽  
Spherical Wrist

SUMMARYThis paper presents a redundant 4-revolute (4R) spherical wrist mechanism for a shoulder exoskeleton, which overcomes several major issues with the 3R mechanisms used in the past. An analysis of the 3R mechanism is done to highlight the limitations in its range of motion and problems caused by operating near singular configurations. To ensure that the redundancy in the 4R mechanism is efficiently utilized, genetic algorithm is used to optimize the mechanism design and identify the optimal operating configurations of the mechanism. The capability to reach the entire shoulder workspace is guaranteed and the joint velocities are minimized by considering the joint displacements required to move the end-effector throughout the workspace and the condition number of joint configurations for reaching 89 positions in the workspace. Analysis of the 4R mechanism obtained from the optimization process indicates that it can move throughout the entire shoulder workspace with feasibly low joint velocities.

scholarly journals A novel 2-DOF planar translational mechanism composed by scissor-like elements

2017 ◽  
Vol 8 (1) ◽  
pp. 179-193 ◽  
Author(s):  
Yi Yang ◽  
Yaping Tian ◽  
Yan Peng ◽  
Huayan Pu
Keyword(s):  
Range Of Motion ◽  
Mechanism Design ◽  
Kinematic Chain ◽  
Stiffness Coefficient ◽  
Work Space ◽  
Recovery Function ◽  
Wide Range ◽  
Elastic Elements

Abstract. The kinematic chain comprised by SLEs (scissor-like elements) has a wide range of motion, which provides a benefit for the mechanism design. A family of SLE-Pa (SLE-parallel) legs which consist of two identical SLE limbs are proposed in this paper. The mobility and kinematics are discussed for three kinds of SLE-Pa legs which are distinguished by the different positions of the middle links in legs. Through assembling these SLE-Pa legs, a novel 2-DOF planar translational mechanism is developed and its work space is studied. For the purpose of adding the recovery function, the elastic elements are installed for this mechanism. The stiffness synthesis of the mechanism is investigated for the various elastic elements and their positions. The approximation of the stiffness coefficient is also derived. Further, this kind of mechanism is applied for the design of the passive docking device. The docking procedure is simulated by Adams, and the prototype of one SLE-Pa leg is presented at the end.

Mechanism Design and Kinematics for Parallel Manipulators with a UPU Limb

2013 ◽  
Vol 694-697 ◽  
pp. 1729-1735
Author(s):  
Xiao Hui Wang ◽  
Jian Jun Zhang ◽  
Kai Cheng Qi ◽  
Wei Min Li
Keyword(s):  
Mechanism Design ◽  
General Structure ◽  
Parallel Manipulators ◽  
Parallel Mechanisms ◽  
Application Area ◽  
Input Output ◽  
Mobile Platforms ◽  
Serial Manipulators ◽  
New Type ◽  
Output Characteristics

The workspace of the parallel manipulators is relatively smaller than the serial manipulators. In order to improve the rotational capability, a new type of parallel manipulators with special topology structures and a special limb is proposed. The peculiarity is that the parallel manipulators involve a UPU limb, which makes their mobile platforms rotate continuously. Mechanisms of the type of parallel manipulators are described, and a general structure for this kind of parallel mechanisms is given. Moreover, their kinematic equations are developed to analyze their input-output characteristics. The research can enlarge the application area.

Statics Analysis of Clemen’s Linkage for Robotic Applications

2013 ◽  
Author(s):  
Derek Lahr ◽  
Dennis Hong
Keyword(s):  
Range Of Motion ◽  
Constant Velocity ◽  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Robotic Manipulators ◽  
Electromechanical Actuators ◽  
Serial Manipulators ◽  
Torque Capacity ◽  
Multiple Actuators ◽  
Robotic Applications

Robotic manipulators can be categorized as either parallel, serial, or in some cases a combination of the two. Among others, a notable drawback of serial manipulators in dynamic applications is the large inertia created by typically heavy electromechanical actuators at the distal end of the manipulator. In addition, compact packaging of multiple actuators in a multi-degree of freedom (DOF) joint, as is often necessary with serial manipulators, can be difficult. These difficulties can be alleviated should a means be found to relocate actuators across one or more degrees of freedom. In this paper, we investigate a constant velocity (CV) linkage, the Clemen’s linkage, that may be used to relocate an actuator across a one DOF revolute joint to an adjacent link while maintaining a serially actuated architecture. This can be very advantageous in some applications such as a humanoid robot ankle. The linkage is analyzed for both its range of motion and torque capacity for such applications given limitations of currently available bearing hardware.

scholarly journals Linkage Design and Optimisation of a Hexapod Walking Robot Used For Surveillance

2019 ◽  
Vol 8 (11) ◽  
pp. 705-708
Keyword(s):  
Basic Structure ◽  
Walking Robots ◽  
Robot Design ◽  
Hexapod Robot ◽  
Walking Robot ◽  
Walking Gait ◽  
Linkage Design ◽  
Robot Leg ◽  
Leg Design ◽  
Basic Movement

The technological advancements at the global level have put in a large demand for walking robots in various industrial and domestic applications. The aim of the paper is to develop a Hexapod (robot with six legs) walking robot that is capable of performing basic movement, such as walking forward and backward, carry payloads and used as a surveillance device. A novel robot leg design has been created with Autodesk Fusion 360, linkage mechanisms of the robot leg is determined by using Linkage 2.0 software. Stress and displacement analysis was done in Autodesk fusion360 software in order to determine whether it can hold the self-weight of the robot and the desired payload to carry the surveillance purpose (i.e. medicine, water, blood etc.). Considering all the possibilities final optimized Hexapod robot design is created using Autodesk Fusion 360 software. Mainly, the undertaken design outline takes into account the fundamental features, such as basic structure, motion planning, payload and walking gait. Fabrication of Hexapod robot parts was completed using additive manufacturing technology FDM process.

Creative Design of an Elliptical Trainer with Two Degrees of Freedom

2008 ◽  
Vol 36 (4) ◽  
pp. 284-293 ◽  
Author(s):  
Hsin-Sheng Lee
Keyword(s):  
Range Of Motion ◽  
Mechanism Design ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Teaching Tool ◽  
Creative Design ◽  
Two Degrees Of Freedom ◽  
Design Requirements ◽  
Number Synthesis

The elliptical trainer is a widely used piece of equipment for fitness and rehabilitation. An elliptical trainer with seven links and eight joints, and two degrees of freedom, can have its range of motion adjusted to match the user's stature, and the user can obtain different athletic effects. It allows for more adjustment than an elliptical trainer with one degree of freedom. In this paper, we refer to the present patents that specify the design requirements and constraints for an elliptical trainer. We then use Yan's creative mechanism design methods, which include generalized principles, number synthesis, specialization, and particularization, to obtain a practicable structure for an elliptical trainer with two degrees of freedom. We obtained five alternative kinds of mechanism. We chose one of them for a simulated kinematic analysis, and manufactured the prototype. This paper can serve not only as a reference for the development of fitness equipment but also as a teaching tool for creative mechanism design courses.

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