End effectors play a privileged role in the manipulation chain. They contact the world. That role gives them an advantageous position to convey function and contribute to a solution to the manipulation problem. This thesis proposal explores the problem of designing the shape of a rigid end effector to perform a given manipulation task.
We present three main contributions: First, a model to describe the contact kinematics of an effector in terms of its shape and motion. Second, a description of contact constraints, their relation to mechanical function, and what it means for an effector to satisfy them. Third, a formulation of Shape-for-Contact, the problem of designing the shape of an effector to comply with a set of contact constraints, and perform the given manipulation task. We illustrate its application to the case studies of designing grippers with invariant grasp geometry and grippers with improved grasp stability.
We propose to derive an optimization-based solution to the Shape-for-Contact problem and extend the current formulation of the concepts of effector and contact constraint satisfaction from planar to spatial mechanisms and from 1 DOF to multiple DOFs. We further propose to apply the technique to the design of a gripper (MLab hand) with a single actuator capable of exerting any combination of power/pinch and spherical/cylindrical grasps.
This thesis proposal demonstrates applications in the context of the design of grasping fingers. However, the formalization of the concept of effector shape is agnostic to application. As a result, the approach is, in principle, applicable to other rigid effectors used to manipulate the environment such as feet or wheels.