Mobile Heave Compensator with Passive-Active Hybrid Control
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Solution Overview
Problem
Traditional active heave compensators lack a passive backup system, are typically non-mobile, and incur high capital and maintenance costs, with poor performance in rough seas and limited operational weather windows due to high power demand and lack of models for heavy lifts.
Innovation Solution
A mobile active heave compensator with a passive heave compensation part and an active heave compensation part, integrated with a sensor arrangement and a power source, utilizing hydraulic fluid pumps and gas accumulators for efficient control of motion, allowing self-support and reduced wear on crane wire ropes, and capable of operating without external energy sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional active compensators are permanently installed on vessels, then heave compensation performance is improved, but capital binding increases and mobility is lost
Solution Approach 1:
The heave compensator is divided into separate modular components including a passive compensator unit with gas accumulators and an active compensator unit with hydraulic actuators, allowing the system to be transported and reinstalled on different vessels as needed
2Measurement precision
If active heave compensation is implemented, then motion control precision is improved, but power demand increases
Solution Approach 1:
The system dynamically switches between passive and active compensation modes based on sea state conditions, using the passive gas accumulators for baseline compensation and activating hydraulic actuators only when higher precision is needed, thereby reducing overall power consumption
Solution Approach 2:
The active compensation system operates periodically rather than continuously, activating hydraulic actuators during critical phases of the heave cycle or when precision requirements exceed passive capability, reducing energy demand while maintaining control precision
3Reliability
If passive backup system is added to active compensator, then reliability is improved, but device complexity increases
Solution Approach 1:
The passive gas accumulator compensator and active hydraulic compensator are merged into a single integrated unit with shared components such as the cylinder, piston, and control system, allowing the passive system to serve as both a backup and a load-bearing element, thereby reducing overall complexity despite improved reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mobile active heave compensator enhances performance and operational availability, reduces wear on crane systems, and lowers costs by providing effective motion control and reduced energy consumption, enabling operations in rougher seas with improved precision and reliability.
Implementation Method 1
Gas accumulators for efficient control of motion
Implementation Method 2
utilizing hydraulic fluid pumps and gas accumulators for efficient control of motion
Data Source
AI summary
The publication describes a mobile active heave compensator provided with an attachment device for suspending the compensator from a load bearing device and an attachment device for carrying a payload. The compensator comprises a passive heave compensation part and an active heave compensation part and is associated with a sensor arrangement producing input signals for a control unit and a power source. The compensator incorporates a hydraulic fluid pump and/or motor device, affecting the active heave compensating part, producing output signal(s) to the hydraulic fluid and/or motor device to transport the hydraulic fluid as required, based on input signals received from the sensor arrangement.