An instrumented manipulandum for human grasping studies

This work presents a novel haptic device to study human grasp, which integrates different technological solutions thus enabling, for the first time, to achieve: (i) a complete grasp characterization in terms of contact forces and moments; (ii) an estimation of contact point location for varying-orientation contact surfaces; (iii) a compensation of force/torque offsets and estimation of the mass and center of mass of the device, for different orientations and configurations in the workspace; (iv) different stiffness properties for the contact points, i.e. rigid, compliant non-deformable and compliant deformable, thus allowing to study the effects of cutaneous cues in multi-finger grasps. In addition, given the modularity of the architecture and the simple mechanism to attach/detach the contact modules, this structure can be easily modified in order to analyze different multi-finger grasp configurations. The effectiveness of this device was experimentally demonstrated and applications to neuroscientific studies and state of the art of devices for similar investigations are discussed in depth within the text.