Roger Bostelman, “Performance Measurement of Mobile Manipulators”, University of Burgundy, Dijon, France, U.F.R. Sciences et Techniques, Thesis for Doctor of the University, Specialty: Computer Science, 16 March, 2018.
An advanced approach to flexible manufacturing is to move robotic manipulators, using an AGV or mobile robot, called mobile manipulators, between workstations. The use of mobile manipulators can be advantageous in a number of situations. It can result in cost savings when a single mobile manipulator can be used to replace several stationary manipulators. However, mobile manipulators are “a relatively young discipline within robotics.” An extensive literature review of the research leading to commercial mobile manipulators and mobile robots was performed. The performance measurement of mobile manipulators, including a mobile base with an onboard robot arm, is virtually non-existent. However, mobile manipulators are beginning to appear in manufacturing, healthcare, and possibly other industries and therefore, a method to measure their performance is critical to both manufacturers and users of these relatively complex systems. Measurements of mobile manipulators performing standard tasks (poses and motions) are also non-existent except for simply ensuring that the task has been more or less completed. The task chosen for this thesis is assembly due to its requirement for relatively precise system posing.
Performance test methods have lagged behind safety test methods for mobile manipulators which is progressing towards development of a new safety standard in the US. Metrics for safety and performance of mobile manipulators include many areas, such as: safe operation, task completion, time to complete the task, quality, and quantity (i.e., accuracy and repeatability, respectively) of tasks completed. Prior to industrial acceptance and standards development for mobile manipulators, users of these new systems will expect manufacturers to provide real performance data to guide their procurement and assure suitability for given application tasks. Due to the relatively high cost to procure and setup motion tracking systems to measure systems performance, an alternative method for use by manufacturers and users is ideal. A new test method concept that uses an artifact, called the Reconfigurable Mobile Manipulator Artifact (RMMA), is described in this thesis and compared to an optical tracking system that was used as ground truth for the RMMA and mobile manipulator.
System modeling the mobile manipulator system, components, and the associated measurements can help to improve the understanding of these relatively complex systems. Systems Modeling Language (SysML) was chosen and used throughout this thesis because of SysML has reusable software modules for structure, behavior, requirements and parametrics off the mobile manipulator. The models describe the many aspects of measuring mobile manipulator performance also as new research area. The models were evaluated through experiments on an example mobile manipulators’ components and the entire system. SysML was used to describe the theoretical basis of the performance through propagation of uncertainty where mathematical equations are also modeled.
A use case is modeled and described where the concepts researched to measure mobile manipulator performance are applied to a manufacturing implementation. The simplistic nature of the measurement process using the RMMA can be directly applied to today’s manufacturing processes, and extended beyond the contributions of this research to other even more complex measurement needs. The research is also discussed to even apply to cross-industry test methods for exoskeletons worn by humans.
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