Summary for CIFE Seed Proposals for Academic Year 2019 20 Proposal number: 2019 05 Proposal title: Leveraging Human Robot Collaboration in Construction
up to 150 words) The problem: Current construction robots rely on bulky industrial robotic arms and simplistic control leading to unsafe operating conditions and limited capabilities that do not leverage human expertise. The proposed solution: Rethink construction tasks using compact, compliant, safe, and multi purpose robots enabling collaboration between humans and robots. The proposed research approach: Develop a haptic simulation environment to explore light weight, multi robot collaborative systems with human interaction for five hazardous and strenuous construction tasks. The results will be experimentally validated. 1 The PI(s) must be academic council member(s) at Stanford. 2 For this and the next points, delete the answers that don't apply to your proposal. Engineering or Business Problem Robotic applications are being developed and tested on construction to handle heavy, repetitive, and hazardous tasks like drywalling, bricklaying, and welding. These robots mostly rely on bulky industrial robotic arms and overly simplistic control algorithms, leading to unsafe operating conditions and limited capabilities that do not leverage human expertise while performing the construction task on site, other than in the role of an operator that oversees robotic performance. In addition, the techniques and products used in construction (from brick sizes to gypsum board dimensions) come from a long history of development and traditions based on labor intensive processes. Efficient robotization may require rethinking some of these methods and standards (Bernold, 1987) By replacing the human worker with a single task machine we could be overlooking what is the best possible product and process for the construction task. Theoretical and Practical Points of Departure Construction task automation: Previous research has evaluated which operations are the most suitable to be robotized and automated. According to Bernold (1987) manufacturing achieved mass production with intensive research and restructuring of their traditional methods to make them more amenable to automation. At that time, both the construction industry mindset and the available technology were not ready to efficiently identify and automate the repetitive tasks that take part in construction projects (Bernold, 1987) Kangari (1985) and Skibniewski Nof (1989) referred to repetitive construction operations by breaking them down into individual processes, tasks, and sub tasks. Similarly, Bernold proposed a hierarchical structure of construction activities as a guideline to evaluate their potential for robotization following six hierarchy levels: organization, project, activity, process, work task, and motion The first three levels were evaluated as unique and non repetitive activities, while the process, work task, and motion were considered semi repetitive and repetitive, and thus optimal for on site robotization (Figure 1) For example, we could characterize earthmoving as the sequence of loading, dumping, and traveling tasks, and each of these tasks could again be decomposed into several motions such as grab, put, turn, and push. To decompose these complex processes on repetitive tasks we should analyze in detail the present construction method, the robotic alternatives and components for each option, and the process to automate the construction task (Warszawski,1989) <Fischer, Khatib> Human Robot collaboration> 2 Figure 1: Example of a functional breakdown structure (Bernold, 1987) According to Skibniewski and Nof (1989) and Warszawski (1989) the value of robotization of tasks increases when these happen in high altitude, extended periods of overtime work, or under any hazardous condition. Some of these tasks are structured enough to be autonomously performed by a robot, while others must still rely on human workers capabilities (Khatib, 1998) The unstructured and dynamic environment of the construction field poses considerable technical challenges (Kangari, 1985) and, even with today's technologies, construction robotics mostly consist of industrial arms mounted in moving platforms performing a single task (Ragaglia et al. 2017; Usmanov et al. 2017; Yamada et al. 2017; Zedin et al. 2017) This configuration has led to complex set ups and programming, non versatile, bulky, stiff, and unsafe robots that do not leverage human collaboration in the field. Inspiration from robotics: State of the art robotics has progressed in mobility, autonomous manipulation skills, AI reasoning and planning, and physical interaction with unstructured environments through multimodal sensing and environment modeling. These capabilities are key to the application of robotics in space, underwater, domestic environments, medical settings, and construction (Khatib, 1998) These environments are challenging for robots because they are highly unstructured and dynamic, changing even while the task is performed (Groll et al. 2017; Kangari, 1985) While the manufacturing industry has traditionally separated workers from robots for safety reasons, integration of humans and robots in the construction industry constitutes a key ergonomic study (Skibniewski Nof, 1989) Ergonomic studies demonstrate the human intent and address how motions can be optimized on the basis of least energy consumption and safety (Bernold, 1989) To successfully introduce robotics in the human environment we need to <Fischer, Khatib> Human Robot collaboration> 3 develop practical, compliant safe, and easy to use systems that are as reliable as the human 3 worker (Khatib, 1998) The use of bimanual robotic manipulation, despite its many advantages, is rare in industrial applications (Kempe, 2007; Smith, 2012) Nevertheless, previous research has provided useful implementation models of two hand object assembly, where the objects held by the robot are increasingly constrained either with respect to the ground or with respect to each other. This gives rise to constraint forces which must be explicitly controlled to prevent damage to the object and control slippage. The virtual linkage model provides a mathematical foundation to control these constraint forces (Khatib, 1996; Williams, 1993) Furthermore, the augmented object model (Chang, 2000) can be used to describe the dynamic behavior of the two manipulators plus object system. Motion coordination for multiple mobile robots and human robot collaboration leveraging bimanual manipulation has been previously considered for drywall operations (Khatib, 1998) This approach incorporated a combination of autonomous behaviors and guided motion interactions for collaboration between humans and robots (Figure 2) The experiments showed the robots could improve the quality and reduce the strain required to perform the task manually, while the workers contribute their knowledge and experience (Khatib, 1998) Figure 2: Robotics in construction drywall (Khatib, 1998) Humans and robots can also collaborate with a haptic visual interface that combines the dexterity, flexibility, problem solving, and expertise of humans with the strength, endurance, and precision of robots in the field. A successful example is Ocean One. This underwater humanoid robot successfully exploits collaboration between a robot and a human to execute tasks at depths where divers cannot reach. The human operator is able to feel exactly what the robot feels through a haptic interface used to guide and control the robot (Figure 3) 3 Compliance refers to the flexibility of the robot to adapt to external forces or torques. The opposite, a non compliant or stiff robot, is a device designed to have predetermined positions or trajectories that cannot be easily altered Belanger Barrette 2014) <Fischer, Khatib> Human Robot collaboration> 4 Figure 3: A human operator guiding the robot in an underwater bimanual task through the haptic visual interface (Khatib et al. 2016)