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Multi-robotic fabrication method has potential to build complex, stable, three-dimensional constructions

Figure 1: Multi-robotic assembly of spatial discrete elements structures.
Figure 1: Multi-robotic assembly of spatial discrete elements structures. Source: NCCR Digital Fabrication.

Multi-robotic fabrication methods can strongly increase the potential of robotic fabrication for architectural applications through the definition of cooperative assembly tasks. As such, the objective of this research is to investigate and develop methods and techniques for the multi-robotic assembly of discrete elements into geometrically complex space frame structures.

This endeavour implies the definition of an integrative digital design method that leads to fabrication and structure informed assemblies that can be automatically built up into custom configurations. The research is being conducted at Gramazio Kohler Research as part of the interdisciplinary research program of the Swiss National Centre of Competence in Research (NCCR) Digital Fabrication. It started in September 2014 by Stefana Parascho and currently includes collaborations with Augusto Gandía and Thomas Kohlhammer.

Spatial Structures

Space frames structures developed during the industrial revolution as efficient systems for large-span constructions, but quickly reached a limitation of their variability through the necessity of standardisation as well as complex connection detailing. Through the development of a multi-robotic assembly method as well as an integrated joining system, irregular space frame geometries become buildable, enhancing existing typologies through their potential for variability and efficient material use. The use of robotic fabrication techniques and the avoidance of pre-fabricated, rigid connections lead to a system that relies not only on digital planning and manufacturing but includes digital assembly as an addition to the digital chain. A process of robotic build-up of triangulated structures was developed, based on the alternating placement of rods. This way, one robot always serves as a support for the already built structure while the other assembles a new element (Figure 02). As a result, the built structures do not require any additional support structures and are constantly stabilised by the robots.

Figure 2: Conceptual Diagram of multi-robotic assembly strategy, exemplified through the sequential build-up of a spatial triangulated structure. Two robots are alternating in order to position the elements and at the same time serve as support structure.
Figure 2: Conceptual Diagram of multi-robotic assembly strategy, exemplified through the sequential build-up of a spatial triangulated structure. Two robots are alternating in order to position the elements and at the same time serve as support structure. Source: NCCR Digital Fabrication.

Integrative Design Methods

Traditional architectural design methods commonly follow a top-down strategy in which both construction and fabrication are subordinated to a previously predefined geometry. In an integrative design approach, the fabrication, structural performance and given boundary constraints can simultaneously function as design drivers, allowing for a much higher flexibility and performance of the system. As such, the presented research focuses on the development of a design strategy in which various factors, such as constraints and characteristics of the multi-robotic fabrication process, are included in the geometric definition process of the structures.

Multi-robotic fabrication

The use of multiple robots for the assembly of discrete element structures opens up potentials for the build-up of complex, stable, three-dimensional constructions. At the same time, the process introduces various challenges such as the necessity for collision avoidance strategies between multiple robots and respective robotic path planning. In order to generate buildable structures, the design process needs to integrate the robots’ constraints, such as robot reach and kinematic behaviour, and at the same time process data from robotic simulation in order to foresee the robots’ precise movements. Through the collaboration with Augusto Gandía from Gramazio Kohler Research a strategy for implementing robotic simulation into a CAD environment and for generating collision free trajectories for multi-robotic applications was developed.

Figure 3: Mid-air build-up of tetrahedral structure without the use of any additional support structure. Source: NCCR Digital Fabrication.
Figure 3: Mid-air build-up of tetrahedral structure without the use of any additional support structure. Source: NCCR Digital Fabrication.

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In automation we trust: senior thesis project examines concept of over-trusting robotic systems

Serena Booth and her robot, Gaia, in its cookie-delivery disguise. (Photo by Adam Zewe/SEAS Communications.)
Serena Booth and her robot, Gaia, in its cookie-delivery disguise. (Photo by Adam Zewe/SEAS Communications.)

By Adam Zewe

Hollywood is to be believed, there are two kinds of robots, the friendly and helpful BB-8s, and the sinister and deadly T-1000s. Few would suggest that “Star Wars: the Force Awakens” or “Terminator 2: Judgment Day” are scientifically accurate, but the two popular films beg the question, “Do humans place too much trust in robots?”

The answer to that question is as complex and multifaceted as robots themselves, according to the work of Harvard senior Serena Booth, a computer science concentrator at the John A. Paulson School of Engineering and Applied Sciences. For her senior thesis project, she examined the concept of over-trusting robotic systems by conducting a human-robot interaction study on the Harvard campus. Booth, who was advised by Radhika Nagpal, Fred Kavli Professor of Computer Science, received the Hoopes Prize, a prestigious annual award presented to Harvard College undergraduates for outstanding scholarly research.

During her month-long study, Booth placed a wheeled robot outside several Harvard residence houses. While she controlled the machine remotely and watched its interactions unfold through a camera, the robot approached individuals and groups of students and asked to be let into the keycard-access dorm buildings.

Booth's robot, Gaia, waits outside the entrance to Quincy House. (Image courtesy of Serena Booth.)
Booth’s robot, Gaia, waits outside the entrance to Quincy House. (Image courtesy of Serena Booth.)

When the robot approached lone individuals, they helped it enter the building in 19 percent of trials. When Booth placed the robot inside the building, and it approached individuals asking to be let outside, they complied with its request 40 percent of the time. Her results indicate that people may feel safety in numbers when interacting with robots, since the machine gained access to the building in 71 percent of cases when it approached groups.

“People were a little bit more likely to let the robot outside than inside, but it wasn’t statistically significant,” Booth said. “That was interesting, because I thought people would perceive the robot as a security threat.”

In fact, only one of the 108 study participants stopped to ask the robot if it had card access to the building.

But the human-robot interactions took on a decidedly friendlier character when Booth disguised the robot as a cookie-delivering agent of a fictional startup, “RobotGrub.” When approached by the cookie-delivery robot, individuals let it into the building 76 percent of the time.

“Everyone loved the robot when it was delivering cookies,” she said.

The cookie delivery robot successfully gained entrance into the residence hall. (Image courtesy of Serena Booth.)
The cookie delivery robot successfully gained entrance into the residence hall. (Image courtesy of Serena Booth.)

Whether they were enamored with the knee-high robot or terrified of it, people displayed a wide range of reactions during Booth’s 72 experimental trials. One individual, startled when the robot spoke, ran away and called security, while another gave the robot a wide berth, ignored its request, and entered the building through a different door.

Booth had thought individuals who perceived the robot to be dangerous wouldn’t let it inside, but after conducting follow-up interviews, she found that those who felt threatened by the robot were just as likely to help it enter the building.

“Another interesting result was that a lot of people stopped to take pictures of the robot,” she said. “In fact, in the follow-up interviews, one of the participants admitted that the reason she let it inside the building was for the Snapchat video.”

While Booth’s robot was harmless, she is troubled that only one person stopped to consider whether the machine was authorized to enter the dormitory. If the robot had been dangerous—a robotic bomb, for example—the effects of helping it enter the building could have been disastrous, she said.

A self-described robot enthusiast, Booth is excited about the many different ways robots could potentially benefit society, but she cautions that people must be careful not to put blind faith in the motivations and abilities of the machines.

“I’m worried that the results of this study indicate that we trust robots too much,” she said. “We are putting ourselves in a position where, as we allow robots to become more integrated into society, we could be setting ourselves up for some really bad outcomes.”

Airborne tech is coming to the rescue

L'Aquila, Abruzzo, Italy. A goverment's office disrupted by the 2009 earthquake. Source: Wikipedia Commons
L’Aquila, Abruzzo, Italy. A government’s office disrupted by the 2009 earthquake. Source: Wikipedia Commons

by Fintan Burke

‘There’s no real way to determine how safe it is to approach a building, and what is the safest route to do that,’ said Dr Angelos Amditis of the Institute of Communication and Computer Systems, Greece. ‘Now for the first time you can do that in a much more structured way.’

Dr Amditis coordinates the EU-funded RECONASS project, which is using drones and satellite technology to help emergency workers in post-disaster scenarios.

It’s part of a new arsenal of airborne disaster response technologies which is giving a bird’s eye view of disaster zones to help save lives.

The system developed by RECONASS places wireless positioning tags into a building’s structure, along with strain, temperature and acceleration sensors, either when it is first built or through retrofitting. Then after a disaster strikes drones are deployed to scan the building’s exterior and match data from the sensors to this image to build an accurate representation of the damage.

This allows the system to precisely calculate potential areas of structural weakness in the damaged building, and it can then be paired with satellite data to get an overview of the damage in an area.

‘From one side we have 3D virtual images showing the status of the building … produced by ground sensors’ input, and from the other side we have the 3D real images from the drones and satellite views,’ said Dr Amditis.

‘There’s no real way to determine how safe it is to approach a building, and what is the safest route to do that.’

Dr Angelos Amditis, Institute of Communication and Computer Systems, Greece

Dr Amditis and colleagues are hoping to test the system in September by detonating a mock three-storey building in Sweden to investigate how well the drone technology works.

The end goal is for emergency services to use the drone technology to provide information about the structural state of tagged buildings within the first crucial hours after the disaster.

To boost rescue services’ ability to respond quickly in the event of a crisis, researchers in Spain are working on how to help emergency helicopter pilots successfully navigate through a disaster area by giving them more precise and reliable information about their position.

The EU-funded 5 LIVES project is building a system that uses both the newly launched Galileo Global Navigation Satellite System (GNSS) from the European Commission and the European Geostationary Navigation Overlay Service (EGNOS), which reports on the reliability and accuracy of data from satellites.

At the moment, most European helicopters use visual navigation, meaning they cannot fly in bad conditions such as fog, clouds or bad weather.

While more and more are beginning to use GNSS technology, the system has been known to be affected by slight changes in the earth’s atmosphere. There is also no way of knowing how accurate the information is.

‘With conventional GNSS technology positioning, there are a lot of external effects that might negatively affect the precision of positioning,’ said project manager Santi Vilardaga of Barcelona-based Pildo Labs.

In order to encourage the adoption of GNSS technology, the 5 LIVES system overlays information from EGNOS to confirm the precision and accuracy of satellite data.

‘Different parameters that affect the displacement of the signal or the propagation of the satellite signal through the atmosphere are collected through a network of ground-based stations and then transferred to the geostationary satellites that then broadcast the corrections to the EGNOS users,’ he said.

More flexible

This extra precision and confidence in the data allows emergency helicopters to become more flexible. ‘They can operate at night, they can operate technology in meteorological conditions without need of added technology on the ground,’ said Vilardaga.

They are also designing drone-based search and rescue operations. Drones can be used to fly around disaster areas, using on-board cameras to continue the search for survivors even when weather conditions make it unsafe for human pilots to do so, explains Vilardaga.

The team is now ensuring that the drones satisfy existing European regulation and their new positioning technology is up to standard for a demonstration of their search and rescue procedures next year.

The need for a new way to combat natural disasters from the air is being driven in part by a new type of crisis – so-called mega-fires. These once-rare fires, which are known to spread at a rate of more than three acres per second, are forest fires large enough to spread between fire-fighting jurisdictions.

A variety of factors such as drought, climate change and the practice of preventing smaller fires to develop naturally have all been blamed for the increasing frequency of mega-fires.

To defend against these fires, the EU-funded Advanced Forest Fire Fighting project is trying to improve both firefighting logistics and technology.

One method involves developing a pellet made of extinguishing materials which can be dropped from a greater height, meaning pilots are less likely to encounter risks from smoke or heat from the fire.

Another area under development is centralising the information from satellite data, drones and ground reports into what is being called a core expert engine to help firefighters to prioritise procedures.

‘The commander can have at his disposal just one aircraft with a pellet,’ said project coordinator Cecilia Coveri of Finmeccanica SpA, Italy, ‘and in case the pellet is the best way to extinguish a fire … this simulation can help the commander to take this decision.’

The project begins its first trials in Athens during the summer in cooperation with Greek naval forces, with additional testing of the risk analysis and simulation tools to follow.

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Photos from the Airbus Shopfloor Challenge


Robohub covered the Airbus Shopfloor Challenge that took place during #ICRA16 in Stockholm. Below, you can see an extensive photo gallery as part of our coverage. Check it out!

Team Naist


Team Naist, from Nara Institute of Science and Technology, Japan won first prize. They used a KUKA robot arm, an advanced head with stabilizing rods, and an advanced computer vision system that enabled them to drill holes efficiently and with great precision.



Team CriGroup


Team CriGroup is based at the School of Mechanical and Aerospace Engineering, within Nanyang Technological University in Singapore. They used ready made parts and a Denso arm with a special focus on software. Their method produced an innovative drilling pattern that minimized robot motion. They came in second place.



Team Sirado


Team Sirado brings together 6 researchers from the graduate School of Engineering, Arts et Métiers Lille campus, and 3 experienced industrial representatives from KUKA Systems Aerospace France, and KUKA Automatisme Robotique SAS. They also used a KUKA arm and a specially designed drill unit. Sirado took third place in the competition.



Team R3


R3 is a robotics collective based out of Ryerson University in Ontario, Canada. Their custom-made XY platform used 7 drill bits in one unit to drill many holes at once. They performed two rounds and competed on the final round.


Team Vayu


Team Vayu from India brings together five undergraduate students who share a passion for aerospace. They had the simplest approach with a compact 3 axis robot that performed well throughout the challenge.


Team Akita Prefectural University


Japanese team Akita Prefectural University implemented a unique solution for the challenge. Their robot used a delta-based solution to place the drill bit accurately. The arms themselves used rolled metallic tape under restrictors to extend and contract. They were able to demonstrate their setup, but weren’t able to compete.


Team Bug Eaters


The Bug Eaters team from the University of Nebraska-Lincoln, USA is made up of four undergraduate Mechanical and Materials Engineering students. Their robot is an innovative version of the delta robot, but issues with their motors didn’t allow them to perform.

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