Robot design and construction

The group designs and constructs innovative mechatronic devices mainly based on parallel architectures. Our developments include the "Wrenchpad" (a six-axis tactile pad), an original air-pumped positioning table, several tensegrity-based robots, a pentaglide, several variations of the Gough-Stewart platform kinematically equivalent the octahedral manipulator, and a twelve degree-of-freedom ameba-like robot.

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Position analysis of multi-loop linkages

The group develops techniques for linkage position analysis, i.e., for computing all possible configurations that a linkage can adopt, while respecting the kinematic constraints imposed by its joints. The problem finds applications to robotics (direct and inverse kinematics of serial/parallel robots, cooperative manipulation, and closed-chain motion planning), structural biology (conformational analysis of biomolecules), multibody dynamics (initial position and finite displacement problems), and computer-aided design (variational CAD and assembly positioning). The group works essentially along two different approaches, one based on relaxation techniques (see the CUIK project), and the other based on the deduction of characteristic polynomials using Distance Geometry.

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Motion planning

The group also develops methods for closed-chain motion planning. In Robotics, for instance, this problem appears in motion planning for parallel manipulators, in object manipulation with anthropomorphic hands, in constraint-based object positioning, or in surgery or humanoid robots. The problem also appears in Biochemistry, when searching for low-energy paths between different molecular conformations. In all cases, a number of loop-closure constraints give rise to a configuration space of a complex structure on which standard algorithms for motion planning cannot be directly applied. The group addresses this problem using higher-dimensional continuation methods that allow characterizing the configuration space in an incremental way.

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Singularity analysis

Singularities play a prominent role on understanding of a robot's configuration space. Depending on their nature, singularities give rise to dexterity or controllability losses and thus are to be avoided during the normal operation of a robot. They may, however, give rise to mechanical advantage too - i.e., to the transformation of small joint torques into large end-effector forces - which may be beneficial on specific applications. Also, output singularities provide the boundary of the workspace, which is a useful information for the robot designer. As a consequence, the group is developing new geometric tools that allow characterizing and computing the various singularity loci of a manipulator, either for classes of parallel mechanisms, or for general multi-body systems.

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Kinematic and Robot Design Laboratory

The Kinematics and Robot Design Laboratory was created thanks to the financial support of the VALTEC program, co-financed with FEDER funds, of the Autonomous Goverment of Catalonia. It was initially created to validate the practical interest of our parallel robot designs, but it has rapidly derived into an active lab where the prototypes designed by the researchers of the Group of Kinematics and Robot Design are implemented as proofs of concept.