Hydraulic & Electronic Motion Control System Integration
A house is only as good as its foundation. The same is true of a machine’s control system. A lot can be done to optimize its control functions, but you can never compensate for a machine’s flawed hydraulic design. While it’s tempting to initially focus on a machine’s primary touchpoints, a machine will best perform in terms of safety and productivity if you start with the end functions and work backwards. You must start with “what is the end goal,” before deciding, “how will I achieve it.”
Start with Accurate Hydraulic Functionality
Understanding your machine and application needs is always step one in designing a control system. With one crane manufacturer, our engineers analyzed their system and saw that although the original system flow rate was 62 gallons per minute, in order to carry out all desired functions simultaneously, that needed to be adjusted to 95 gpm. However, that high flow rate was not necessary when the machine wasn’t at high pressure. This analysis allowed us to narrow down the exact hydraulic solution, in this instance torque-limited pumps rather than valving, to achieve the desired machine capabilities.
Once you have a firm understanding of the hydraulic requirements, preferred electronics can be integrated into the machine to better control those factors, including ramping, control safety locks, and priority flow. Still, both the hydraulic and electronic components within a control system must be designed with the other in mind. While you need the proper hydraulic foundation in order to correctly set up a machine’s functions, it’s important to also know how you ultimately want to control them.
The Choice Between Hydraulic and Electronic Components
Let’s take a look at joysticks. Historically, operators liked the simplicity of pilot operated hydraulic joysticks and believed they were easier to troubleshoot. The physical feedback that comes with a hydraulic joystick was also seen as a benefit. However, their negatives, the load instability, high stresses that come along with zero ramping abilities, and in-cab oil and hydraulic housing, outweigh the benefits. While an electronic joystick may seem less rugged, you have the ability to easily adjust the ramping parameters within the system’s program. Not only does this feature make it much simpler and faster to make system adjustments, but it’s also much more precise and consistent than any method available with hydraulic controls, like dampening the pilot line.
Perhaps even more importantly, utilizing an electronic joystick can significantly increase your machine’s longevity. When comparing two similar machines, one with a hydraulic and the other with an electronic joystick, doing the same function, over time, the machine that utilized an electronic joystick saw 1/3 of the amount of boom stress utilizing start and stop ramps on the valve.
Integrating Electronic and Hydraulic Features For Increased Machine Efficiency
Another benefit of electronic components is the ability to more precisely control your machine’s hydraulic system. Consider integrating a load sensing function into a lift truck. As that is typically a hydraulic function, it can be adversely affected by temperature. Utilizing electronic load sensing eliminates that issue. You are also able to monitor the function and actually control the pump, as well as eliminate flows and pressure and mitigate load dynamics.
Hydraulic and electronic components both have their advantages. But in order for OEMs to best utilize the maximum benefits from each category, you need to start with the proper hydraulic foundation, and design your electronic system to work hand in hand within that. A machine will perform the most efficiently and safely when both aspects of its system work together.
