1,721,070 research outputs found
A novel kinematic directional index for industrial serial manipulators
Full text linkIn the last forty years, performance evaluations have been conducted to evaluate the behavior of industrial manipulators throughout the workspace. The information gathered from these evaluations describes the performances of robots from different points of view. In this paper, a novel method is proposed for evaluating the maximum speed that a serial robot can reach with respect to both the position of the robot and its direction of motion. This approach, called Kinematic Directional Index (KDI), was applied to a Selective Compliance Assembly Robot Arm (SCARA) robot and an articulated robot with six degrees of freedom to outline their performances. The results of the experimental tests performed on these manipulators prove the effectiveness of the proposed index
A sensorless approach for cable failure detection and identification in cable-driven parallel robots
Full text linkCable-driven parallel robots (CDPRs) are a particular class of parallel robots that provide several advantages that may well be received in the industrial field. However, the risk of damage due to cable failure is not negligible, thus procedures that move the end-effector to a safe pose after failure are required. This work aims to provide a sensorless failure detection and identification strategy to properly recognize the cable failure event without adding additional devices. This approach is paired with an end-effector recovery strategy to move the end-effector towards a safe position, thus providing for a complete cable failure recovery strategy, which detects the failure event and controls the end-effector accordingly. The proposed strategy is tested on a cable-driven suspended parallel robot prototype composed of industrial-grade components. The experimental results show the feasibility of the proposed approach
A Comparison of Control Strategies for Collaborative Mobile Robots
No full textMobile collaborative robots are more and more common in the industrial scenario, increasing the workspace of collaborative manipulators and, thus the shared workspace. This work compares different admittance controllers for mobile collaborative robots. In particular, we focused on an application where a human operator manually moves a mobile collaborative robot by applying forces to a collaborative manipulator attached to the mobile platform. Three different forms of admittance control were presented and tested with experiments on a real mobile robot. Finally, the capabilities of these controllers were compared
Exploiting the Redundancy of Cable Suspended Parallel Robots for the Actuation of the End-Effector
No full textCable-driven parallel robots are a class of parallel robots whose performance, and lightweight and inexpensive design are of interest for industrial applications. For the design to be effective in the industrial field, an end-effector should be designed, and traditional end-effectors require an external power source for the actuation, which can be limiting in larger workspaces. This work presents the design of an end-effector which exploits the redundancy in the tension configuration to actuate a gripper. To fully exploit the variation in cable tension, a force-transmission mechanism is presented. Given the influence of the end-effector Cartesian position on the tension configuration, this work presents the available gripping force in the robot workspace. The results show a promising solution for the design, which is effective in grasping a mass of 1.5 kg in the workspace
Integrated electromechanical simulation of traction systems: Relevant factors for the analysis and estimation of energy efficiency
No full textElectromechanical analysis and simulation of traction systems are required to estimate the power consumption, to size the power system and to optimize system parameters for energy saving. The number of variables and parameters (mechanical and electrical) is huge, affected by various degrees of uncertainty. An integrated simulation approach is presented, where the requisites for the correct evaluation of regenerative capability are considered. © 2012 IEEE
A framework for the integration of traditional and collaborative robotics
No full textIn recent years, a new type of robotic manipulator, i.e., collaborative robots (cobots), was introduced in the market. Their ability to share the workspace with the operator without any safety fences allows automating tasks that were too difficult or too expensive to automate. Moreover, collaborative workcells merge the flexibility of the human operator and the accuracy of automated systems. However, they are usually separated from the main industrial plant, reducing their influence on the process. Hence, a framework to connect traditional and collaborative robotics is presented in this work. The framework is developed in three layers with a top-down approach, where a first offline layer will solve the task scheduling problem of a human-robot collaborative workcell. Due to the unpredictability of the human operator, it is important to develop a second layer to monitor the operator and dynamically adapt the cobot. A possible implementation with depth cameras is presented along with a control scheme. Lastly, a third layer is responsible for the connection between the collaborative workcell and the other devices connected to the process line. A case study presents a possible application of the proposed approach
Robotic Additive Printing of Cylindrical Auxetic Structures
No full textAdditive manufacturing technologies represent an interesting solution to aid companies to offer a wide range of customized products. Furthermore, they allow printing complex lattice and auxetic structures. The use of robot manipulators for 3D printing allows overcoming several limitations of traditional additive manufacturing systems, i.e. low surface quality (stair-casing effects) and undesirable anisotropic properties, so as to print complex geometries on curved surfaces. This work presents an experimental setup designed to print cylindrical auxetic structures composed of a 3D printer and a robotic arm. The system produces the part without any assembly and avoiding stair-case effects. Furthermore, using the robot for moving the printing based simplified the control system and allows for simpler printing devices
Analytical Movement Optimization of Dual-Arm Planar Robots with Rotating Platform
Full text linkIn the last years some industrial robots have been realized with two robot arms connected to a single rotating platform. Such a redundant structure allows moving the platform to adjust each robot base for optimizing each arm movement. In this paper, a planar model of two 7-axis robots connected to a rotating platform is proposed, and a novel analytical optimization procedure, retrieved from a geometrical analysis, is presented
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