Wire Harness Assembly Process Supported by Collaborative Robots: Literature Review and Call for R&D

The wire harness assembly process is a complicated manufacturing activity, which is becoming more complex because of the evolving nature of mechatronic and electronic products that require more connectors, sensors, controllers, communication networking, etc. Furthermore, the demand for wire harnesses continues to grow in all industries worldwide as the majority of equipment, appliances, machinery, vehicles, etc., are becoming "smart" (i.e., more mechatronic or electronic). Moreover, most of the wire harness assembly process tasks are done manually, and most of these are considered non-ergonomic for human assembly workers. Hence, the wire harness manufacturing industry is faced with the challenge of increasing productivity while improving the occupational health of its human assembly workers. The purpose of this paper is to conduct a literature review exploring the state of the use of collaborative robots in the wire harness assembly process due to their potential to reduce current occupational health problems for human assembly workers and increase the throughput of wire harness assembly lines, and to provide main findings, discussion, and further research directions for collaborative robotics in this application domain. Eleven papers were found in the scientific literature. All papers demonstrated the potential of collaborative robots to improve the productivity of wire harness assembly lines, and two of these in particular on the ergonomics of the wire harness assembly process. None of the papers reviewed presented a cost-benefit or a cycle time analysis to qualitatively and/or quantitatively measure the impact of the incorporation of collaborative robots in the wire harness assembly process. This represents an important area of opportunity for research with relevance to industry. Three papers remark on the importance of the integration of computer vision systems into a collaborative wire harness assembly process to make this more versatile as many types of wire harnesses exist. The literature review findings call for further research and technological developments in support of the wire harness manufacturing industry and its workers in four main categories: (i) Collaborative Robotics and Grippers, (ii) Ergonomics, (iii) Computer Vision Systems, and (iv) Implementation Methodologies

Preliminary design of a 100 kW turbine generator

The National Science Foundation and the Lewis Research Center have engaged jointly in a Wind Energy Program which includes the design and erection of a 100 kW wind turbine generator. The machine consists primarily of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades operates at 40 rpm and generates 100 kW of electrical power at 18 mph wind velocity. The entire assembly is placed on top of a tower 100 feet above ground level

Continuous maintenance and the future – Foundations and technological challenges

High value and long life products require continuous maintenance throughout their life cycle to achieve required performance with optimum through-life cost. This paper presents foundations and technologies required to offer the maintenance service. Component and system level degradation science, assessment and modelling along with life cycle ‘big data’ analytics are the two most important knowledge and skill base required for the continuous maintenance. Advanced computing and visualisation technologies will improve efficiency of the maintenance and reduce through-life cost of the product. Future of continuous maintenance within the Industry 4.0 context also identifies the role of IoT, standards and cyber security

Space shuttle avionics system

The Space Shuttle avionics system, which was conceived in the early 1970's and became operational in the 1980's represents a significant advancement of avionics system technology in the areas of systems and redundacy management, digital data base technology, flight software, flight control integration, digital fly-by-wire technology, crew display interface, and operational concepts. The origins and the evolution of the system are traced; the requirements, the constraints, and other factors which led to the final configuration are outlined; and the functional operation of the system is described. An overall system block diagram is included

Geometric-based Optimization Algorithms for Cable Routing and Branching in Cluttered Environments

The need for designing lighter and more compact systems often leaves limited space for planning routes for the connectors that enable interactions among the system’s components. Finding optimal routes for these connectors in a densely populated environment left behind at the detail design stage has been a challenging problem for decades. A variety of deterministic as well as heuristic methods has been developed to address different instances of this problem. While the focus of the deterministic methods is primarily on the optimality of the final solution, the heuristics offer acceptable solutions, especially for such problems, in a reasonable amount of time without guaranteeing to find optimal solutions. This study is an attempt to furthering the efforts in deterministic optimization methods to tackle the routing problem in two and three dimensions by focusing on the optimality of final solutions. The objective of this research is twofold. First, a mathematical framework is proposed for the optimization of the layout of wiring connectors in planar cluttered environments. The problem looks at finding the optimal tree network that spans multiple components to be connected with the aim of minimizing the overall length of the connectors while maximizing their common length (for maintainability and traceability of connectors). The optimization problem is formulated as a bi-objective problem and two solution methods are proposed: (1) to solve for the optimal locations of a known number of breakouts (where the connectors branch out) using mixed-binary optimization and visibility notion and (2) to find the minimum length tree that spans multiple components of the system and generates the optimal layout using the previously-developed convex hull based routing. The computational performance of these methods in solving a variety of problems is further evaluated. Second, the problem of finding the shortest route connecting two given nodes in a 3D cluttered environment is considered and addressed through deterministically generating a graphical representation of the collision-free space and searching for the shortest path on the found graph. The method is tested on sample workspaces with scattered convex polyhedra and its computational performance is evaluated. The work demonstrates the NP-hardness aspect of the problem which becomes quickly intractable as added components or increase in facets are considered

UNMANNED GROUND VEHICLE (UGV) DOCKING, CONNECTION, AND CABLING FOR ELECTRICAL POWER TRANSMISSION IN AUTONOMOUS MOBILE MICROGRIDS

Autonomous Mobile Microgrids provide electrical power to loads in environments where humans either can not, or would prefer not to, perform the task of positioning and connecting the power grid equipment. The contributions of this work compose an architecture for electrical power transmission by Unmanned Ground Vehicles (UGV). Purpose-specific UGV docking and cable deployment software algorithms, and hardware for electrical connection and cable management, has been deployed on Clearpath Husky robots. Software development leverages Robot Operating System (ROS) tools for navigation and rendezvous of the autonomous UGV robots, with task-specific visual feedback controllers for docking validated in Monte-Carlo outdoor trials with a 73% docking rate, and application to wireless power transmission demonstrated in an outdoor environment. An “Adjustable Cable Management Mechanism” (ACMM) was designed to meet low cost, compact-platform constraints for powered deployment and retraction by a UGV of electrical cable subject to disturbance, with feed rates up to 1 m/s. A probe-and-funnel AC/DC electrical connector system was de- veloped for deployment on UGVs, which does not substantially increase the cost or complexity of the UGV, while providing a repeatable and secure method of coupling electrical contacts subject to a docking miss-alignment of up to +/-2 cm laterally and +/-15 degrees axially. Cabled power transmission is accomplished by a feed-forward/feedback control method, which utilizes visual estimation of the cable state to deploy electrical cable without tension, in the obstacle-free track of the UGV as it transverses to connect power grid nodes. Cabling control response to step-input UGV chassis velocities in the forward, reverse, and zero-point-turn maneuvers are presented, as well as outdoor cable deployment. This power transmission capability is relevant to diverse domains including military Forward-Operating-Bases, disaster response, robotic persistent operation, underwater mining, or planetary exploration

Development and Launch of the World\u27s First Orbital Propellant Tanker

This paper describes the development of Orbit Fab’s Tanker-001 Tenzing mission, the world’s first orbital propellant tanker. The development of a robust orbital propellant supply chain is critical to accelerating the growth of government and commercial space activities. The widespread availability of spacecraft refueling has the potential to provide a number of revolutionary benefits. High-value space assets could have their operational lives extended, as they would no longer be constrained by the amount of propellant stored onboard for maneuvering. On-orbit servicing missions would become more efficient, as servicing vehicles could be refueled and repeatedly used. A large orbital propellant supply would also enable new mission and business models based on operational flexibility and frequent maneuvering. These benefits would be particularly impactful on small satellites, where the ability to refuel could overcome the operational constraints of having smaller propellant tanks. This will greatly expand the market for small spacecraft as it increases their range of missions and capabilities. Launching no earlier than June 24, 2021, Tenzing is a 35 kg small satellite with an Astro Digital bus carrying a supply of storable propellant, high test peroxide (HTP). Tenzing’s propellant supply is being offered to customers for refueling and used to gather data on propellant storage. In addition to being the first propellant tanker, Tenzing is also an orbital laboratory including a variety of payloads intended to test key technologies for refueling. This includes the first flight of Orbit Fab’s Rapidly Attachable Fluid Transfer Interface (RAFTI), a stereo camera system, and a Halcyon HTP propulsion system designed and built by Benchmark Space Systems for orbital maneuvers. The latter two elements can be used to test rendezvous and flyby maneuvers, providing data to support the development of full rendezvous, proximity operations, and docking (RPOD) systems for future Orbit Fab missions