Sharif Digital Repository

Object handling is one of the most important applications of cable-suspended robots, which can be obtained by use of a gripper as its end-effector. In this paper, a novel cable-driven multi-finger gripper assembled on a cable-suspended robot has been presented. Using lock/unlock mechanisms, the under-actuated finger mechanism has been designed to have a human like motion. A cable-suspended robot structure with 3 position degrees of freedom is also proposed by employing active/passive cables in such a way that makes it capable of resisting external moments, while it may be simplified to a spatial point-mass cable robot during positioning operation. Furthermore, the robot workspace has been... 

This paper presents the measurements results of simulated partial discharge propagation on a compact three phase XLPE cable, and shows how the high frequency signal on one phase of the cable is induced on the other two phases. A frequency dependent three phase cable model is employed to simulate this phenomena. © 2008 Australasian Universities Power Engineering Conference (AUPEC'08)  

In this paper, modeling and control of a new cable-driven robot is presented. In this mechanism, the cable arrangement eliminates the rotational motions leaving the moving platform with three translational motion. The mechanism has potentials for large scale manipulation and robotics in harsh environments. In this article kinematics and dynamics models for the proposed cable-driven architecture are derived. Additionally, Feedback linearization under input constraints is used for the control of the robot. The control algorithm ensures the cable tensions are positive while minimizing the sum of all the torques exerted by the actuators. Finally, the implementation of the proposed method is... 

The application of manipulators is becoming more and more popular in object handling especially when it is desired to have access to remote areas in destructive or hazardous taskspaces. For this purpose, a hand-like mechanism must be designed to be used as an end-effector, which can grasp objects. In this paper a cable driven grasping mechanism has been presented. In the proposed mechanism each finger consists of three phalanxes which are actuated by a single motor. Locking and unlocking constraints are used in the mechanism in order to generate an anthropomorphic motion, in which, the order of reaching phalanxes to the object is sequential. In this way, each phalanx starts moving toward the... 

In this paper, modeling and control of a new cable-driven robot is presented. In this mechanism, the cable arrangement eliminates the rotational motions leaving the moving platform with three translational motion. The mechanism has potentials for large scale manipulation and robotics in harsh environments. In this article kinematics and dynamics models for the proposed cable-driven architecture are derived. Additionally, Feedback linearization under input constraints is used for the control of the robot. The control algorithm ensures the cable tensions are positive while minimizing the sum of all the torques exerted by the actuators. Finally, the implementation of the proposed method is... 

This article proposes modelling, simulation and applied wrench workspace analysis of a 3D cable based robots which are consist of six cables are studies. After modelling, the kinds of workspace are defined then an available static combined workspace for different geometric structures of fixed and moving platform is obtained. This workspace is defined as the situations of reference point of the moving platform (center of mass) which under external forces such as weight and with ignorance of inertial effects, the end effector should be in static equilibrium under conditions that length of all cables must not be exceeded from the maximum value and all of cables must be at tension (they must... 

Online monitoring of HV XLPE cables is a major interest for utilities. Due to severe and rapid risk of life of this type of cable with occurrence of partial discharges, studies are carried out for detection and location of PD. However there is a lack of models that can help to accurately detect the partial discharge and its location in installed cables, due to the relatively long length and the load condition of cable. Detection and location of any partial discharge signal requires: A verified knowledge of phenomena which contributes to P.D. propagation and its deformation, measured data of P.D. type signal propagation on different cable test setups, accurate frequency dependent cable model... 

Cable-driven parallel robots have several outstanding characteristics that make them unique in many robotic applications. Since cables can only pull, one of the most important issues associated with these robots is obtaining their workspace. In this paper a spatial translational cable-driven robot with active/passive cables is considered and its workspace is investigated from several points of views. First the moment resisting capability of the robot is discussed and the effects of some robot's parameters on the workspace are studied. Then, both force-feasibility and moment-resisting capability of the robot are considered to find the region where the end-effector may exert the required... 

In this paper, modeling and control of a new cable-driven robot is presented. In this mechanism, the cable arrangement eliminates the rotational motions leaving the moving platform with three translational motion. The mechanism has potentials for large scale manipulation and robotics in harsh environments. In this article kinematics and dynamics models for the proposed cable-driven architecture are derived. Additionally, Feedback linearization under input constraints is used for the control of the robot. The control algorithm ensures the cable tensions are positive while minimizing the sum of all the torques exerted by the actuators. Finally, the implementation of the proposed method is... 

This paper presents the design and the application of a new self-powered hybrid electromagnetic damper that can harvest energy while mitigating the vibration of a structure. The damper is able to switch between an energy harvesting passive mode and a semi-active mode depending on the amount of energy harvested and stored in the battery. The energy harvested in the passive mode resulting from the suppression of vibration is employed to power up the monitoring and electronic components necessary for the semi-active control. This provides a hybrid control capability that is autonomous in terms of its power requirement. The proposed hybrid circuit design provides two possible options for the... 

This paper presents a kinematics and workspace analysis of cable-suspended manipulators with elastic cable. The mechanics of extensible cable with a deflection to its selfweight are studied. The problem of evaluating the workspace is approached by using a modified formulation for a deformable cable. The proposed algorithm for testing whether a given configuration lies within the reachable workspace is applied. Starting with a general statement of the kinetic equations of the elastic cable and incorporate cable flexibility into workspace generation. This algorithm is verified through simulation results of various cable-suspended robots. © 2008 IEEE  

In under-constrained spatial cable suspended robots, maximum number of cables are equivalent to the number of degree of freedom, therefore the equations of kinetostatic have unique solutions and invention of positive cable tensile forces in these robots must come into being by redundant cables, springs or by Moving Platform (MP) weight. In this research, MP weight is considered to create tension in cables so both increasing workspace volume and decreasing possibility of cable encounter with together can be created because of using less cables. The range of MP weight to generate tension in cables is calculated by using Interval method, optimum weight is selected and then optimal tension... 

The design of a new cable-driven robot for large-scale manipulation is presented with focus on the tension condition in the cables. In this robot, the arrangement of the cables is such that the moving platform has three translational motions. The robot has potentials for large-scale robotic manipulations, machining of large parts and material handling. The design analysis presented here is towards the synthesis of the robot as well as the sizing of the actuators and cables. The synthesis of this robot is dependent on the results of the tensionable workspace analysis previously published by the Alikhani et al. [6]. The analysis of the cable forces is presented in detail, which is then used to... 

An effective iterative method is proposed for three-dimensional large-displacement analysis of structures consisting of slack cables as the primary load-bearing system. This approach takes advantage of substructuring technique that is specially tailored to address the analysis and form-finding problem of slack cables subjected to arbitrary loads, and to reduce the overall analysis costs. At the overall structural level, a robust procedure is employed for detecting the instabilities and limiting the corresponding incremental displacements. The effectiveness of the proposed method for the analysis of highly unstable or variable-form structures is demonstrated by a number of analysis examples... 

This paper discusses the necessity of considering the concurrent effects of uniform temperature and earthquake loadings in the design of cable-stayed bridges. This load combination is not foreseen in current design standards such as AASHTO and Eurocode. Three-dimensional finite element models of cable-stayed bridges are employed for nonlinear time history analyses. A load combination is proposed that adds uniform temperature loading to the existing extreme event load combination. The proposed combination is compared with existing extreme event load combination and the changes in forces and displacements are noted. A parametric study is then conducted by varying a number of properties of the... 

A cable-driven mechanism based on the idea of BetaBot (2005, "A New Cable-Based Parallel Robot With Three Degrees of Freedom, " Multibody Syst. Dyn., 13, pp. 371-383) is analyzed and geometrical description of its workspace boundary is found. In this mechanism, the cable arrangement eliminates the rotational motions leaving the moving platform with three translational motions. The mechanism has potentials for large scale manipulation and robotics in harsh environments. A detailed analysis of the tensionable workspace of the mechanism is presented. The mechanism, in a tensionable position, can develop tensile forces in all cables to maintain its rigidity under arbitrary external loading. A... 

The objective of this paper is designing, modeling and wrench feasible workspace analysis of a 3D cable suspended robot as IRPM (Incompletely Restrained Positioning Mechanism). This type of robots supports a load platform in space by less than or equal to six spatially arranged cables. We use the model of 6 cables spanned in the same manner as a Stewart parallel mechanism. This mechanism is suitable for the accurate positioning of heavy loads. Concentrating on the operations of heavy loads handling, studying the workspace and ways of increasing it is of high importance. Several workspaces exist amongst which the constant and total orientation statically reachable combined and wrench feasible... 

The detection and location of any Partial Discharge (PD) signal requires an accurate frequency dependent cable model to correctly simulate the PD signal attenuation during its propagation in the cable. This model should be capable of simulating the semiconducting layers, which have significant effects on PD signal attenuation and its propagation velocity. There is a substantial need for improvements in the flexibility of the transient cable model through direct introduction of the two semiconducting layers in the cable model. This can be employed in the next step to develop a 3-phase cable model for ATP. This paper has derived an impedance formula for the semiconducting layers. The... 

Detection and location of any partial discharge signal requires an accurate frequency dependent cable model to correctly simulate the P.D. signal attenuation during its propagation in the cable. This model should be capable of simulating the semiconducting layers which have significant effects on P.D. signal attenuation and its propagation velocity. There is a substantial need for improvements in the flexibility of transient cable model through direct introduction of the two semiconducting layers in the cable model. This can be employed, in the next step to develop a 3 phase cable model for ATP. This paper has derived an impedance formula for the semiconducting layers. The propagation...