An Open-Source Integration Platform for Multiple Peripheral Modules with Kuka Robots

This paper presents an open-source software interface for the integration of a Kuka robot with peripheral tools and sensors, KUI: Kuka User Interface. KUI is developed based on Kuka Fast Research Interface (FRI) which enables soft real-time control of the robot. Simulink Desktop Real-Time™ or any User Datagram Protocol (UDP) client can send real-time commands to Kuka robot via KUI. In KUI, third-party tools can be added and controlled synchronously with Kuka light-weight robot (LWR). KUI can send the control commands via serial communication to the attached devices. KUI can generate low-level commands using data acquisition (DAQ) boards. This feature enables rapid prototyping of new devices for the Kuka robot. Type II Reflexxes Motion Library is used to generate an online trajectory for Kuka LWR and the attached devices in different control modes. KUI is capable of interfacing a broad range of sensors such as strain gauges, compression load cells, pressure sensors/barometers, piezoresistive accelerometers, magnetoresistive sensors (compasses) using either a DAQ board or through the connection interface of amplified bridges. Sensors data, as well as all robot parameters such as joint variables, Jacobian matrix, mass matrix, etc. can be logged during the experiments using a separate stable thread. All these capabilities are readily available through a multithreaded graphical user interface (GUI). Three experimental case studies are presented to demonstrate the capabilities of the software in action. KUI is freely available as open source software under GPL license and can be downloaded from https://github.com/mahyaret/KUI

A New Approach for Grasp Quality Calculation using Continuous Boundary Formulation of Grasp Wrench Space

In this paper, we aim to use a continuous formulation to efficiently calculate the well-known wrench-based grasp metric proposed by Ferrari and Canny which is the minimum distance from the wrench space origin to the boundary of the grasp wrench space. Considering the L∞ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 16.200000762939453px; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3e metric and the nonlinear friction cone model, the challenge of calculating this metric is to determine the boundary of the grasp wrench space. Instead of relying on convex hull construction, we propose to formulate the boundary of the grasp wrench space as continuous functions. By doing so, the problem of grasp quality calculation can be efficiently solved as typical least-square problems and it can be easily implemented by employing off-the-shelf optimization algorithms. Numerical tests will demonstrate the advantages of the proposed formulation compared to the conventional convex hull-based methods

Grasp Evaluation Method for Applying Static Loads leading to Beam Failure

This paper deals with the problem of purposefully failing or yielding an object by a robotic gripper. We propose a grasp quality measure fabricated for robotic harvesting in which picking a crop from its stem is desired. The proposed metric characterizes a suitable grasp configuration for systematically controlling the failure behavior of an object to break it at the desired location while avoiding damage on other areas. Our approach is based on failure task information and gripper wrench insertion capability. Failure task definition is accomplished using failure theories. Gripper wrench insertion capability is formulated by modeling the friction between the object and gripper. A new method inspired by human pre-manipulation process is introduced to utilize gripper itself as a friction measurement device. The provided friction model is capable of handling the anisotropic behavior of materials which is the case for fruits and vegetables. The evaluation method is formulated as a quasistatic grasp problem. Additionally, the general case of both fully-actuated and under-actuated grippers are considered. As a validation of the proposed evaluation method, experimental results for failing parts using Kuka Light-Weight Robot IV robot are presented

A lightweight magnetorheological actuator using hybrid magnetization

Copyright © 2020, IEEE This paper presents the design and validation of a lightweight Magneto-Rheological (MR) clutch, called Hybrid Magneto-Rheological (HMR) clutch. The clutch utilizes a hybrid magnetization using an electromagnetic coil and a permanent magnet. The electromagnetic coil can adjust the magnetic fieldgenerated by the permanent magnet to a desired value, and fully control the transmitted torque. To achieve the maximum torque to mass ratio, the design of HMR clutch is formulated as a multiobjective optimization problem with three design objectives, namely the transmitted torque, the mass of the clutch, and themagnetic field strength within the clutch pack. A prototype of the HMR clutch is fabricated and its dynamic performance is experimentally validated. Experimental results clearly demonstrate the advantages of the HMR clutch in applications requiring fast and precise motion and torque control. This article presents the design and validation5 of a lightweight magnetorheological (MR) clutch, called hy6brid magnetorheological (HMR) clutch. The clutch utilizes7 a hybrid magnetization using an electromagnetic coil and8 a permanent magnet. The electromagnetic coil can adjust9 the magnetic field generated by the permanent magnet to10 a desired value and fully control the transmitted torque. To11 achieve the maximum torque-to-mass ratio, the design of12 the HMR clutch is formulated as a multiobjective optimiza13tion problemwith three design objectives, namely the trans14mitted torque, themass of the clutch, and themagnetic field15 strength within the clutch pack. A prototype of the HMR16 clutch is fabricated, and its dynamic performance is ex17perimentally validated. Experimental results clearly demon18strate the advantages of the HMR clutch in applications19 requiring fast and precise motion and torque control

Optimal Grasp Synthesis to Apply Normal and Shear Stresses of Failure in Beams

This paper investigates the less-studied problem of failing/yielding an object purposefully by a robotic hand. A grasp synthesis capable of using the whole limb surface of the robotic hand is designed based on internal force decomposition. The introduced approach is based on quasistatic assumption and optimization of active internal forces in order to counterbalance the formulated task wrench/load of yielding. As different geometrical constraints are dictated by the manipulation circumstances (e.g. metallic sheet shaping or robotic harvesting), the yielding wrench optimization is developed to be not only sufficient for yielding the object but also effective in meeting all motion restrictions on manipulator. Maximum shear- stress theory is used for yielding analysis of a grasped object. Finite Element Modeling (FEM) simulation results are provided as a validation of our proposed approach

Development of MR Clutch for a Prospective 5-DOF Robot

This paper presents an improved design approach for the construction of a Magneto-Rheological (MR) clutch intended to be used in a prospective 5 degrees of freedom robot. The MR clutch features embedded Hall sensors for intrinsic torque control. After a brief description of the MR clutch principles, the details of the mechanical design are discussed. Simulation and preliminary experimental results demonstrate the main characteristics and advantages of the proposed MR clutch