Talk 1 : Sensory Substitution using 3-Degree-of-Freedom Tangential and Normal Skin Deformation Feedback Speaker : Zhan Fan Quek Advisor : Allison Okamura Abstract: During manual interactions, we experience both kinesthetic forces and tactile sensations. Friction and normal force between the fingerpads and the tool/interaction surfaces cause shear and normal deformation of the skin. Capitalizing on this observation, we designed a 3-degree-of-freedom (DoF) tactile device that is grasped by a user and can render both tangential skin stretch and normal deformation on the skin of the user's fingerpads. Tactile feedback from the device is delivered in a manner consistent with natural tactile cues from manual interaction. An experiment assessed the accuracy with which users can locate the center of a contoured hole on a virtual surface. The task was completed under four conditions: the cases of skin deformation and force feedback, with both 3- and 1-DoF feedback in each case. With 3-DoF feedback, users located the hole faster and more accurately than with 1-DoF feedback, for both force and skin deformation feedback. These results indicated that users were able to interpret the additional DoF cues provided by our 3-DoF tactile device to improve task performance. Talk 2 : Scalable Control of Pin Arrays Speaker : Ryder Winck Advisor : Allison Okamura Controlling a pin array haptic device is challenging in part due to the many inputs required. This presentation discusses the application of singular value decomposition (SVD) within a feedback control system, called the SVD System, to control numerous subsystems with a reduced number of control inputs. The subsystems are coupled using a row-column structure to permit mn subsystems to be controlled using m+n inputs. The SVD System permits simultaneous control of every subsystem, which increases the convergence rate by an order of magnitude compared with previous methods. Talk 3 : Combining Haptics and Functional Neuroimaging to Study Human Motor Control Speaker : Samir Menon Advisor : Oussama Khatib Abstract: Recent advances in combining haptics and virtual simulation with functional magnetic resonance imaging (fMRI) have enabled experiments that map complex unconstrained motions on to the brain. Reliably mapping neural responses to complex motor tasks, however, requires careful haptics engineering to avoid imaging artifacts, along with intuitive experiments that elicit reliable responses. In this talk, I will discuss our work in developing fMRI-compatible haptic interfaces and demonstrate that these interfaces avoid common neuroimaging artifacts. I will also demonstrate how well designed experiments can help overcome limits on fMRI's indirect and slow measurements of neural activity. Finally, I will show that our interface and experiment protocol can reliably elicit and localize heterogeneous neural activation in motor, pre-motor, and somatosensory cortex. Talk 4 : Simulation-based Design of Performance Enhancing Devices for a Standing Long Jump Speaker : Carmichael Ong Advisor : Scott Delp Abstract: Advances in robotic technology have recently enabled the development of wearable devices aimed at assisting human movement. A major challenge in their development is characterizing how these devices interact with the neuromuscular system. My work addresses this challenge by creating accurate simulations of a standing long jump that enable the study of how external actuation of lower body joints affects neuromuscular performance. A planar, six segment (foot, shank, thigh, head-torso, upper arm, and lower arm) model was implemented in OpenSim, a musculoskeletal modeling package, and was driven by physiologically accurate torque actuators at the ankle, knee, hip, and shoulder. Dynamic optimization was used to solve for the set of torque-time profiles that maximize jumping distance while respecting joint limits and minimizing slipping during takeoff. The simulations were then augmented with an actuator that can provide up to 50 Nm of extension torque at the ankle, knee, or hip, and optimization was performed again. The optimization of the unassisted model yielded a simulated motion that captured salient features of kinematics and joint torques in comparison with experimental data of standing long jumps. Optimization of the model augmented with an actuator at the ankle, knee, or hip predicts that extra extension torque at the knee would yield the best improvement. This work serves as a first step to creating a framework for simulation-based design of augmentative devices.