When we want a cup of coffee, our need to drink is at the forefront of our consciousness. On a subconscious level, our brain handles the tasks of moving our hand to the cup, grasping the cup, lifting the cup, and bringing it toward our mouth.
To accomplish this feat, the brain constantly monitors the position of the hand (our proprioceptive sense), the contact between the hand and the cup (our cutaneous sense), and the force with which we grip the cup (our kinesthetic sense). If the cup is almost full or if there is moisture on the outside of the cup or our hand, we instinctively grip the cup more firmly. Likewise, we can feel the dynamic movement of the liquid in the cup and adjust our limb movement to keep the liquid from spilling. These three senses, proprioceptive, cutaneous, and kinesthetic, comprise our haptic sense, or as it is more commonly known, our sense of touch.
Our sense of touch is vital to most tasks involving physical interaction with the world around us. Imagine trying to drink the cup of coffee with you hands and fingers anesthetized. Yet, there are situations in which the sense of touch is not available. For many of these, haptic feedback technologies hold the potential to restore the sense of touch.
Two situations in particular that are the focus of our research are the application of haptic feedback technologies to upper-limb prostheses and minimally invasive surgical robots.