358 research outputs found
Control of Cooperating Mobile Manipulators
We describe a framework and control algorithms for coordinating multiple mobile robots with manipulators focusing on tasks that require grasping, manipulation and transporting large and possibly flexible objects without special purpose fixtures. Because each robot has an independent controller and is autonomous, the coordination and synergy are realized through sensing and communication. The robots can cooperatively transport objects and march in a tightly controlled formation, while also having the capability to navigate autonomously. We describe the key aspects of the overall hierarchy and the basic algorithms, with specific applications to our experimental testbed consisting of three robots. We describe results from many experiments that demonstrate the ability of the system to carry flexible boards and large boxes as well as the system’s robustness to alignment and odometry errors
Control of Cooperating Mobile Manipulators
We describe a framework and control algorithms for coordinating multiple mobile robots with manipulators focusing on tasks that require grasping, manipulation and transporting large and possibly flexible objects without special purpose fixtures. Because each robot has an independent controller and is autonomous, the coordination and synergy are realized through sensing and communication. The robots can cooperatively transport objects and march in a tightly controlled formation, while also having the capability to navigate autonomously. We describe the key aspects of the overall hierarchy and the basic algorithms, with specific applications to our experimental testbed consisting of three robots. We describe results from many experiments that demonstrate the ability of the system to carry flexible boards and large boxes as well as the system’s robustness to alignment and odometry errors
Safety Awareness for Rigid and Elastic Joint Robots: An Impact Dynamics and Control Framework
This thesis aims at making robots with rigid and elastic joints aware of human collision safety. A framework is proposed that captures human injury occurrence and robot inherent safety properties in a unified manner. It allows to quantitatively compare and optimize the safety characteristics of different robot designs and is applied to stationary and mobile manipulators. On the same basis, novel motion control schemes are developed and experimentally validated
Hybrid Force-Impedance Control for Fast End-Effector Motions
Controlling the contact force on various surfaces is essential in many robotic applications such as in service tasks or industrial use cases. Mostly, classical impedance and hybrid motion-force control approaches are employed for these kinds of physical interaction scenarios. In this work, an extended Cartesian impedance control algorithm is developed, which includes geometrical constraints and enables explicit force tracking in a hybrid manner. The unified framework features compliant behavior in the free (motion) task directions and explicit force tracking in the constrained directions. Advantageously, the involved force subspace in contact direction is fully dynamically decoupled from dynamics in the motion subspace. The experimental validation with a torque-controlled robotic manipulator on both flat and curved surfaces demonstrates the performance during highly dynamic desired trajectories and confirms the theoretical claims of the approach
Enabling technologies for precise aerial manufacturing with unmanned aerial vehicles
The construction industry is currently experiencing a revolution with automation techniques
such as additive manufacturing and robot-enabled construction. Additive Manufacturing (AM)
is a key technology that can o er productivity improvement in the construction industry by
means of o -site prefabrication and on-site construction with automated systems. The key
bene t is that building elements can be fabricated with less materials and higher design freedom
compared to traditional manual methods.
O -site prefabrication with AM has been investigated for some time already, but it has limitations
in terms of logistical issues of components transportation and due to its lack of design
exibility on-site. On-site construction with automated systems, such as static gantry systems
and mobile ground robots performing AM tasks, can o er additional bene ts over o -site
prefabrication, but it needs further research before it will become practical and economical.
Ground-based automated construction systems also have the limitation that they cannot extend
the construction envelope beyond their physical size. The solution of using aerial robots
to liberate the process from the constrained construction envelope has been suggested, albeit
with technological challenges including precision of operation, uncertainty in environmental
interaction and energy e ciency.
This thesis investigates methods of precise manufacturing with aerial robots. In particular,
this work focuses on stabilisation mechanisms and origami-based structural elements that allow
aerial robots to operate in challenging environments. An integrated aerial self-aligning delta
manipulator has been utilised to increase the positioning accuracy of the aerial robots, and
a Material Extrusion (ME) process has been developed for Aerial Additive Manufacturing
(AAM). A 28-layer tower has been additively manufactured by aerial robots to demonstrate the
feasibility of AAM. Rotorigami and a bioinspired landing mechanism demonstrate their abilities
to overcome uncertainty in environmental interaction with impact protection capabilities and
improved robustness for UAV. Design principles using tensile anchoring methods have been
explored, enabling low-power operation and explores possibility of low-power aerial stabilisation.
The results demonstrate that precise aerial manufacturing needs to consider not only just the
robotic aspects, such as
ight control algorithms and mechatronics, but also material behaviour
and environmental interaction as factors for its success.Open Acces
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