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  1. In modern industrial manufacturing processes, robotic manipulators are routinely used in the assembly, packaging, and material handling operations. During production, changing end-of-arm tooling is frequently necessary for process flexibility and reuse of robotic resources. In conventional operation, a tool changer is sometimes employed to load and unload end-effectors, however, the robot must be manually taught to locate the tool changers by operators via a teach pendant. During tool change teaching, the operator takes considerable effort and time to align the master and tool side of the coupler by adjusting the motion speed of the robotic arm and observing the alignment from different viewpoints. In this paper, a custom robotic system, the NeXus, was programmed to locate and change tools automatically via an RGB-D camera. The NeXus was configured as a multi-robot system for multiple tasks including assembly, bonding, and 3D printing of sensor arrays, solar cells, and microrobot prototypes. Thus, different tools are employed by an industrial robotic arm to position grippers, printers, and other types of end-effectors in the workspace. To improve the precision and cycle-time of the robotic tool change, we mounted an eye-in-hand RGB-D camera and employed visual servoing to automate the tool change process. We thenmore »compared the teaching time of the tool location using this system and compared the cycle time with those of 6 human operators in the manual mode. We concluded that the tool location time in automated mode, on average, more than two times lower than the expert human operators.« less
  2. Recent advancements in additive manufacturing such as Direct Write Inkjet printing introduced novel tools that allow controlled and precise deposition of fluid in nano-liter volumes, enabling fabrication of multiscale structures with submillimeter dimensions. Applications include fabrication of flexible electronics, sensors, and assembly of Micro-Electro-Mechanical Systems (MEMS). Critical challenges remain in the control of fluid deposition parameters during Inkjet printing to meet specific dimensional footprints at the microscale necessary for the assembly process of microscale structures. In this paper we characterize an adhesive deposition printing process with a piezo-electric dispenser of nano-liter volumes. Applications include the controlled delivery of high viscosity Ultraviolet (UV) and thermal curable adhesives for the assembly of the MEMS structures. We applied the Taguchi Design of Experiment (DOE) method to determine an optimal set of process parameters required to minimize the size of adhesive printed features on a silicon substrate with good reliability and repeatability of the deposition process. Experimental results demonstrate repeatable deposition of UV adhesive features with 150 μm diameter on the silicon substrate. Based on the observed wettability effect of adhesive printed onto different substrates we propose a solution for further reduction of the deposit-substrate contact area for microassembly optimization.
  3. The sAFAM is a novel mm-size microrobot built using MicroElectroMechanical Systems (MEMS) technology. It consists of a monolithically fabricated microrobotic arm assembled onto four in-plane actuators, capable of moving along four degrees of freedom, including translational movement in X and Y axes as well as pitch and yaw. In this paper, several design modifications were proposed to increase movement precision, stability, and controllability to the sAFAM tip. An interface is developed to assist a human operator accurately position the microrobot tip during nano-object handling. A Python-based graphical user interface (GUI) was programmed to make it intuitive for an operator to use and obtain required tip precision under a microscope. Experimental results demonstrate the functionality of the proposed control solution, and the tip motion resolution using microscope images of the microrobot tip under 20x magnification during operation. The hardware and software requirements for the proposed experimental setup and control platform are discussed in detail.
  4. Industrial robots, as mature and high-efficient equipment, have been applied to various fields, such as vehicle manufacturing, product packaging, painting, welding, and medical surgery. Most industrial robots are only operating in their own workspace, in other words, they are floor-mounted at the fixed locations. Just some industrial robots are wall-mounted on one linear rail based on the applications. Sometimes, industrial robots are ceiling-mounted on an X-Y gantry to perform upside-down manipulation tasks. The main objective of this paper is to describe the NeXus, a custom robotic system that has been designed for precision microsystem integration tasks with such a gantry. The system tasks include assembly, bonding, and 3D printing of sensor arrays, solar cells, and microrobotic prototypes. The NeXus consists of a custom designed frame, providing structural rigidity, a large overhead X-Y gantry carrying a 6 degrees of freedom industrial robot, and several other precision positioners and processes. We focus here on the design and precision evaluation of the overhead ceiling-mounted industrial robot of NeXus and its supporting frame. We first simulated the behavior of the frame using Finite Element Analysis (FEA), then experimentally evaluated the pose repeatability of the robot end-effector using three different types of sensors. Results verifymore »that the performance objectives of the design are achieved.« less
  5. Direct write Inkjet Printing is a versatile additive manufacturing technology that allows for the fabrication of multiscale structures with dimensions spanning from nano to cm scale. This is made possible due to the development of novel dispensing tools, enabling controlled and precise deposition of fluid with a wide range of viscosities (1 – 50 000 mPas) in nano-liter volumes. As a result, Inkjet printing has been recognized as a potential low-cost alternative for several established manufacturing methods, including cleanroom fabrication. In this paper, we present a characterization study of PEDOT: PSS polymer ink deposition printing process realized with the help of an automated, custom Direct Write Inkjet system. PEDOT: PSS is a highly conductive ink that possesses good film forming capabilities. Applications thus include printing thin films on flexible substrates for tactile (touch) sensors. We applied the Taguchi Design of Experiment (DOE) method to produce the optimal set of PEDOT:PSS ink dispensing parameters, to study their influence on the resulting ink droplet diameter. We experimentally determined that the desired outcome of a printed thin film with minimum thickness is directly related to 1) the minimum volume of dispensed fluid and 2) the presence of a preprocessing step, namely air plasmamore »treatment of the Kapton substrate. Results show that an ink deposit with a minimum diameter of 482 μm, and a thin film with approximately 300 nm thickness were produced with good repeatability.« less
  6. Abstract Microassembly systems utilizing precision robotics have long been used for realizing three-dimensional microstructures such as microsystems and microrobots. Prior to assembly, microscale components are fabricated using micro-electromechanical-system (MEMS) technology. The microassembly system then directs a microgripper through a series of automated or human-controlled pick-and-place operations. In this paper, we describe a novel custom microassembly system, named NEXUS, that can be used to prototype MEMS microrobots. The NEXUS integrates multi-degrees-of-freedom (DOF) precision positioners, microscope computer vision, and microscale process tools such as a microgripper and vacuum tip. A semi-autonomous human–machine interface (HMI) was programmed to allow the operator to interact with the microassembly system. The NEXUS human–machine interface includes multiple functions, such as positioning, target detection, visual servoing, and inspection. The microassembly system's HMI was used by operators to assemble various three-dimensional microrobots such as the Solarpede, a novel light-powered stick-and-slip mobile microcrawler. Experimental results are reported in this paper to evaluate the system's semi-autonomous capabilities in terms of assembly rate and yield and compare them to purely teleoperated assembly performance. Results show that the semi-automated capabilities of the microassembly system's HMI offer a more consistent assembly rate of microrobot components and are less reliant on the operator's experience andmore »skill.« less
  7. In this paper, we propose a method for tracking a microrobot’s three-dimensional position using microscope machine vision. The microrobot, theSolid Articulated Four Axis Microrobot (sAFAM), is being developed to enable the assembly and manipulation of micro and nanoscale objects. In the future, arrays of sAFAMS working together can be integrated into a wafer-scale nanofactory, Prior to use, microrobots in this microfactory need calibration, which can be achieved using the proposed measurement technique. Our approach enables faster and more accurate mapping of microrobot translations and rotations, and orders of magnitude larger datasets can be created by automation. Cameras feeds on a custom microscopy system is fed into a data processing pipeline that enables tracking of the microrobot in real-time. This particular machine vision method was implemented with a help of OpenCV and Python and can be used to track the movement of other micrometer-sized features. Additionally, a script was created to enable automated repeatability tests for each of the six trajectories traversable by the robot. A more precise microrobot workable area was also determined thanks to the significantly larger datasets enabled by the combined automation and machine vision approaches. Keywords: Micro robotics, machine vision, nano microscale manufacturing.
  8. Microassembly systems utilizing precision robotics have long been used for realizing 3-dimensional microstructures such as microrobots. Prior to assembly, such components are fabricated using Micro-Electro-Mechanical-System (MEMS) technology. The microassembly system then directs a microgripper through automated or human-controlled pick-and-place operations. In this paper, we describe a novel custom microassembly system, named NEXUS. The NEXUS integrates multi-degree of freedom (DOF) precision positioners, microscope computer vision, and micro-scale process tools such as a microgripper and vacuum tip. A semi-autonomous human-machine interface (HMI) is programmed by NI LabVIEW® to allow the operator to interact with the microassembly system. The NEXUS human-machine interface includes multiple functions, such as positioning, target detection, visual servoing, and inspection. The microassembly system’s HMI was used by operators to assemble various 3-dimensional microrobots such as the Solarpede, a novel light-powered stick-and-slip mobile microcrawler. Experimental results are reported in this paper that evaluate the system’s semi-autonomous capabilities in terms of assembly rate and yield and compare them to purely teleoperated assembly performance. Results show that the semi-automated capabilities of the microassembly system’s HMI offer a more consistent assembly rate of microrobot components.