Towards self-sensed drives in linear haptic systems

Within the framework of a project consisting in developing a novel haptic computer keyboard, force and position control is required for each key. The previous project phase consisted in the design and optimization of a miniature actuator which is to be inserted under each key. This paper addresses the application of self-sensing principles to linear short stroke actuators in order to control their position. Due to the great number of keys, as well as the limited space available under each of them, self-sensing detection appears as a must. A passive method using the coil back emf to determine the key position is presented.