A motion axis driven by a pair of hydraulic cylinders often requires synchronized motion of the cylinders. One of the most common ways of doing this is to incorporate a linear displacement transducer into both cylinders to provide position feedback. Routing signals from the transducers back to an electronic controller. The controller closes the control loop by monitoring position of both cylinders and regulating electrical power to the solenoid(s) controlling each cylinder's proportional directional valve.
However, many applications can forego the cost and complexity of colosed-loop electronic control using only hydraulic components. Here are links to a two-part article we published a few years ago describing ways to synchronize motion of hydraulic cylinders:
But that's not all. We also describe synchronizing circuits in our Fluid Power Handbook & Directory
And if you still want more, our eBook covers synchronizing circuits even more extensively.
But there's nothing like leanring by example, so our eBook also examines the design and operation of circuits in existing systems.