Control of a Scalable Matrix Vasoconstrictor Device for Wet Actuator Arrays

The matrix vasoconstriction device (MVD) is a scalable mechanism than can control the fluid flow through a vascular network with n² wet shape memory alloy (SMA) actuators using 2n+2 constrictors (control elements). This vascular network delivers hot and cold fluid to conductively heat and cool shape memory alloy (SMA) muscles embedded in compliant vessels. The MVD mimics smooth muscles found in biological systems by constricting fluidic vessels to prevent flow. When released, the MVD does not add any fluidic resistance to the system, which has reduced the effective fluid resistance of the vascular network to 20% of the previous vascular system controlled by solenoid valves, therefore increasing the flow rate by a factor of 5. With the MVD´s increased flow rates, a cycling rate of one Hz has been achieved for a single actuator. The MVD has (2n - 1)² possible configurations, which allow fluid flow through a single or multiple vessels at the intersection of one or more released row and column constrictors. As the number of released vessels increases, the total fluid resistance of the system decreases and the total flow through the system increases. Releasing all the constrictors, the flow through a 4 times 4 array can produce 3.5 actuations per unit time (where the unit time is the time necessary to drive a single actuator). This paper examines the operation of the MVD as it controls the ternary fluid flow (hot, cold, no flow) to an n times n array of wet SMA actuators operating independently and operating columns of actuators that are connected mechanically series with each other