This example shows a digital hydraulic actuator that consists of 3 double-acting cylinders mounted in the same shell and interconnected through the hard stops. The gap between the leftmost piston and the shell is equal to 2^0*base_length, the gap between the first and the second pistons is set to 2^1*base_length, and the gap between the second and the third pistons is set to 2^2*base_length. The piston area in the rightmost chamber is half the size of the areas of the other chambers. The rightmost chamber is permanently connected to the pump while the other three chambers are connected either to pump or tank depending on the 2-position 3-way electro-hydraulic valves. As a result, 2^3 discrete positions can be reached within 2^3*base_length range.
The plots below show the pressures in each cylinder chamber and the extension of each cylinder. Six of the eight possible positions are shown during this cycle.