Modelling and control of underactuated finger-based gripper with adjustable compliance for grasping of varying and deformable objects

Finished: 2022-09-27

MSc assignment

Grasping and manipulation of objects remains one of the most challenging problems in robotics. Objects needing to be grasped can vary wildly in size, mass, stiffness, surface and other properties. In contrast, humans from a very young age perform complex grasping and manipulation tasks effortlessly; the human hand is a marvel in its complexity, capability, and robustness.

To achieve satisfactory robustness, most robotic solutions are highly specialized to a particular class of objects where they can perform sufficiently well. However, even within the same object class, inter-object variation can be significant. One such situation occurs in the food processing industry, where natural products such as fruits, vegetables and meats, even of the same type, are highly variable.

The NWO project FlexCRAFT ( aims to bring robust perception, world modelling, control, and gripping manipulation technology to the Dutch agri-food sector. The Robotics and Mechatronics group is involved in P4: Gripping and manipulation. Some of the questions that need to be answered are:

- How do we deal with significant variation in size, shape, stiffness, and surface properties?
- What should an effective gripper for such products look like and what sensing does it need?
- How do we control the gripper for robust manipulation?

This MSc project aims to start addressing these questions. Specifically, the focus is on gripper design, using principles such as underactuation and compliance.

After a study on the available literature on underactuated and compliant gripper designs, concept gripper designs will me modelled and evaluated against simple deformable object models.

Depending on the outcomes, these can then be extended to more complex grippers that include multiple links, underactuation, and/or variable stiffness. If large progress is made, simple prototypes will be constructed using rapid prototyping techniques, to validate the developed techniques in experiment. Testing on a Franka Emika Panda will also be considered as a possiblity.