Steerable Underwater Trenching Apparatus Track Control
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Solution Overview
Problem
Conventional subsea trenching vehicles with articulated tracks face issues such as reduced tractive effort and sinkage during course correction, pitching, and potential damage upon landing due to skid steering, especially in hard seabed soils and when encountering obstacles.
Innovation Solution
An underwater trenching apparatus with steerable endless track units, height adjustment mechanisms, and damping systems to manage contact loads, allowing for independent control of track units for improved maneuverability and even load distribution, reducing the risk of damage during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional skid steering is used to change direction, then the trenching vehicle can correct its course, but the tractive effort is reduced and the tracks sink into the seabed
Solution Approach 1:
The track units are made steerable with independent angular adjustment capability, allowing dynamic redirection of tractive effort vectors. Each track unit can be individually angled to provide steering without relying on differential speed control, maintaining consistent tractive effort while changing direction
Solution Approach 2:
The patent replaces the conventional skid steering mechanism (which relies on differential wheel speeds) with a steerable track system where each track unit can be independently angled. This substitution eliminates the need to reduce tractive effort for direction correction, as steering is achieved through angular orientation rather than speed differential
2Ease of operation
If conventional skid steering is used to change direction, then the trenching vehicle can correct its course, but sinkage of the tracks into the seabed occurs
Solution Approach 1:
The steerable track units allow dynamic steering by angular adjustment rather than speed differential, maintaining stable track contact with the seabed during direction changes and preventing sinkage
Solution Approach 2:
The patent changes the steering parameter from speed differential to angular orientation. Each track unit's angle relative to the vehicle body can be independently adjusted, providing direction control without the adverse effects of skid steering on track stability
3Ease of operation
If conventional skid steering is used, then direction change is possible, but pitching of the vehicle occurs resulting in high loading of the trench forming tool
Solution Approach 1:
The steerable track units enable smooth directional changes by independently angling each track, avoiding the sudden pitching motions that occur with conventional skid steering. This dynamic steering method maintains vehicle stability and consistent tool loading
Solution Approach 2:
The patent changes the steering mechanism from speed-based differential control to angle-based independent track orientation, eliminating the pitching vibrations and sudden load changes on the trench forming tool that characterize conventional skid steering
4Productivity
If the apparatus is lowered from a service vessel at high speed, then deployment is efficient, but the apparatus can be damaged on contact with the seabed
Solution Approach 1:
The height adjustment mechanisms are pre-configured to provide controlled descent and cushion the impact when the apparatus contacts the seabed. The dampers are positioned to absorb shock loads during high-speed deployment, protecting the apparatus from damage while maintaining efficient deployment rates
5Reliability
If height adjustment means is provided for each track unit, then even load distribution is achieved, but the device complexity increases
Solution Approach 1:
The patent divides the track system into independently controllable track units, each with its own height adjustment mechanism. This segmentation allows precise local adjustment of each track's contact pressure, achieving even load distribution across the seabed while maintaining overall system manageability through modular control
Data Source
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AI summary
An underwater trenching apparatus comprises at least one trenching tool; a lifting attachment point configured for attachment of a lifting means for lowering the trenching apparatus to, or raising the trenching apparatus from, its location of operation; at least two steerable endless track units for transmitting tractive effort to move the underwater trenching apparatus in use; and for each steerable endless track unit, a first mounting arrangement permitting rotation of the track unit about a vertical axis, and a first actuator configured to move the track unit about the vertical axis, and control means configured to control the action of the actuator. In alternative forms, in addition to, or alternative to the steerable endless track units, the apparatus includes height adjustment means for adjusting the vertical spacing between the main body portion and the respective endless tracks; and control means configured to control the action of the height adjustment means.