Balanced heave compensation (BHC) is a

heave compensation Heave compensation is motion compensator technology applied to minimizing the vertical movement of a load supported by lifting gear mounted on a Heave (translational motion), heaving platform. Techniques include active heave compensation and pass ...

technology engaging the principle of a

balanced-arm lamp A balanced-arm lamp, sometimes called a floating arm lamp, is a lamp with an adjustable folding arm which is constructed such that the force due to gravity is always counteracted by springs, regardless of the position of the arms of the lamp. Many ...

for offshore

motion compensation Motion compensation in computing is an algorithmic technique used to predict a frame in a video given the previous and/or future frames by accounting for motion of the camera and/or objects in the video. It is employed in the encoding of video ...

Working principle

The technical working principle can be summarized as converting the non-linear

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

of a gas spring or hydro-pneumatic spring into an adjustable, substantially linear force, by several mechanical measures. The technology comprises a series of

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

ed inventions by NHLO licensed to and marketed by Seaqualize. An active balanced heave compensation (ABHC) system adds an active component to a BHC for even further stabilisation of the mass.

Research project

In cooperation with IHC and research partners MARIN and ECN, a scale model of a first device comprising the technology, an offshore access bridge has been tested. Seaqualize is currently working on a full-scale prototype of the access bridge. The project has been subsidized by the

Dutch Ministry of Economic Affairs The Ministry of Economic Affairs (; EZ) is the Netherlands' ministry responsible for international trade, commercial, industrial, investment, technology, space policy, as well as tourism. The Ministry was created in 1905 as the Ministry of Ag ...

as a

renewable energy Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind pow ...

project. The research project indicates balanced heave compensation enables a range of potential benefits compared to currently available solutions. This may lead to improvements and

cost saving Cost reduction is the process used by organisations aiming to reduce their costs and increase their profits, or to accommodate reduced income. Depending on a company’s services or products, the strategies can vary. Every decision in the produc ...

s in (engaging) heave compensation systems.

Comparison to traditional heave compensation systems

Balanced heave compensation (BHC) differs from traditional (spring-based)

passive heave compensation Passive heave compensation is a technique used to reduce the influence of waves upon lifting and drilling operations. A simple passive heave compensator (PHC) is a soft spring which utilizes spring isolation to reduce transmissibility to less th ...

(PHC) and

active heave compensation Active heave compensation (AHC) is a technique used on lifting equipment to reduce the influence of waves upon offshore operations. AHC differs from Passive Heave Compensation by having a control system that actively tries to compensate for any m ...

(AHC) in several ways. In traditional spring based heave compensation systems, the movement of the

mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

is parallel to the movement of the spring cylinder. A passive heave compensation system is in effect a mass spring system: it stabilizes a certain mass in a single position of the spring, in that position only the spring and the mass are balanced. In other positions of the spring, the mass and the spring are not balanced and the mass will tend to start moving towards the stabilized position due to residual forces in the spring. A mass spring system can be beneficial for heave compensation only in certain (preset) conditions: the spring, its excitation, the mass and the frequency of the excitation of the spring all need to be taken into account in order for a mass to be substantially stabilised in a moving environment. In other (unexpected) conditions, mass spring systems may experience unwanted effects such as load amplification: its mass may start to move viciously instead of being stabilised. An active heave compensation system adds an active component to a traditional passive heave compensation system in order to counteract these residual forces / in order to counteract load amplification, in effect minimising the movement of the load. In BHC systems, the movement of the mass is not parallel to the movement of the spring, leading to significantly lower residual forces, and therefore lower requirements on the active components. In BHC systems, load amplification is unlikely to occur since the mass is substantially balanced in the whole range of movement of the spring. Residual forces are minimized and therefore unexpected conditions such as variations in the wave pattern have a negligible effect on the working principle. This leads to a better stabilisation of the mass compared to PHC systems.

References

{{reflist Offshore engineering