Booms on aerial fire trucks are subject to oscillation, also known as boom bounce, as a result of quick movements and disturbances such as wind, the flow of pumped water or individuals on the ladder. Further magnification of this oscillation occurs as the boom extends.

A system solution for aerial fire apparatus has been developed by power management technologies and services company, Eaton, to help original equipment manufacturers (OEMs) eliminate boom bounce and address a variety of challenges and trends in modern aerial design.

The elevation, extension and rotation of the boom are critical hydraulic functions on aerial fire trucks. Whether a pumper or platform model, the boom needs to reach its target location quickly and safely. While modern ramped controls are seen as an improvement over previous models, un-commanded movement resulting from the ramps limits boom extension speed and placement accuracy and, in some cases, ramped controls can also present safety hazards.

Eaton’s system solution for aerial fire apparatus is designed to increase safety and truck capabilities while reducing overall design complexity. The centrepiece of the system is its CMA advanced mobile valve, a Controller Area Network-, or CAN-, enabled electrohydraulic valve with on-board electronics and integrated software algorithms that, beyond the elimination of boom bounce to maintain aerial stability, is said to provide a number of additional advantages. For instance, the system delivers tighter response for increased operator control, helps firefighters to deploy the aerial boom faster and with greater placement accuracy and simplifies aerial apparatus customisation.

The company explains that Boom stability control (BSC) technology, an integrated control ap­plication on the CMA valve, reduces boom oscillation by up to 75% and settling time by up to 90%. BSC can be active even when the operator is not commanding the boom, keeping the aerial apparatus stable and in position at all times.

Eaton asserts that the technology provides su­perior control to augment operator skills, reduce the impact of external disturbances and provide peace-of-mind to those on the ladder or platform. BSC is designed to main­tain apparatus safety and manual override features and works in tandem with the company’s counterbalance valves to reduce CBV-related judder.

The company outlines that its system solution helps to enhance capability, particularly regarding rapid point-to-point movement. The faster a boom can be positioned, the quicker firefighters can get to work, whether accessing a building, rescuing individuals from height or dousing flames. BSC enables operators to deploy and stop the boom more quickly, safely and precisely than ramped controls.

Another benefit relates to system simplification. Growing demand upon aerial fire truck manufacturers to provide customers with ever-increasing levels of customisation means there is a need for simplified interconnected systems. With software-driven configuration and elec­tronic tuning, Eaton’s CMA valve helps to streamline set-up and optimisation. In addition, CAN communication simplifies controller requirements and integration with other CAN-based systems.

OEMs are able to adopt common hard­ware across aerial fire truck models as the software facilitates customisation and advanced controls without the need to change the spools or wiring harness. The valve’s on-board controller and sensors further ease system integration, while also minimising external components and providing a range of data that can serve functions such as load detection – all of which helps to reduce costs and complexity.

In addition, CMA valve banks can be configured with CMA sections and Eaton’s recently introduced CMT sections, enabling OEMs to create a tailored solution that matches performance and capability with the specific machine function.

The overall effect of the system solution is to help counter quick boom movements and external disturbances that can cause boom tip oscillation, as well as overcome limitations regarding the speed and control at which firefighters can deploy a boom, ensuring safety and stability for personnel climbing up ladders on platform trucks.