Digital Clay is an NSF funded project for human machine communication through a tangible haptic surface actuated using fluid power. Digital Clay's hardware can be divided into three subsystems: massive-integrated actuator-sensor array, fluidic driving system, and control system. Focus of this paper is the control of some of the special mechanisms of Digital Clay. Specifically, the Fluid Matrix Drive, Capacitive-Coupled Resistive Sensing technology for position feedback and the other control related issues are discussed. Analysis and testing results on these topics are provided based on a 5x5 actuator array prototype. Most of the topics discussed in this paper are widely applicable to other devices as well as Digital Clay.