Movable Rig Steering System with Electric Drive
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Solution Overview
Problem
Current movable oil rig systems face challenges with environmental risks due to high-pressure hydraulic systems, tire scrubbing, and limited maneuverability, particularly in Arctic environments, where hydraulic fluid leaks and tire failures can lead to spills and stability issues.
Innovation Solution
An electric drive, hydraulic steer system with 8 AC electric motors, right-angle gearboxes, and planetary gearboxes integrated into trunnions, allowing independent control of each tire for balanced speed and torque, along with a double-ended steering cylinder mechanism for improved steering geometry and reduced hydraulic fluid usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-pressure hydraulic systems are used to power the rig, then sufficient power and tractive effort are provided, but the risk of environmental oil spills increases due to hose failure or leaks
Solution Approach 1:
The patent extracts the high-pressure hydraulic power transmission system from the rig and replaces it with electric motors. Each wheel assembly has its own electric motor, eliminating the need for high-pressure hydraulic hoses that traverse the rig structure. This removes the source of potential hydraulic fluid leaks while maintaining the required tractive effort through direct electric propulsion.
Solution Approach 2:
The patent substitutes the mechanical hydraulic power transmission system with an electrical propulsion system. Instead of using hydraulic motors driven by high-pressure fluid, the rig uses electric motors with gearboxes directly mounted on each wheel assembly. This replacement eliminates hydraulic fluid while providing equivalent or superior power delivery and control.
2Ease of operation
If Akermann steering with a long steering bar is used, then steering control is provided, but the system cannot rotate wheel sets 90 degrees without removal of the steering bar which exceeds 15 feet in length and 1000 pounds in weight
Solution Approach 1:
The patent segments the steering function from the traditional long steering bar and distributes it to individual wheel assemblies. Each wheel assembly has its own steering mechanism controlled by independent actuators, eliminating the need for a single long steering bar that must be removed for 90-degree rotations. This segmentation allows each wheel to be steered independently without mechanical interference.
Solution Approach 2:
The patent implements dynamic steering control where each wheel assembly can independently adjust its steering angle through electric actuators. This dynamic system replaces the static, rigid steering bar configuration with movable, independently controlled wheel assemblies that can achieve 90-degree rotations and any intermediate angle without physical constraints.
3Adaptability or versatility
If front and back steering mechanisms are used simultaneously, then maneuverability is improved, but tires may walk off rims because each tire travels about a different center of rotation
Solution Approach 1:
The patent implements feedback control through independent sensors and actuators on each wheel assembly. The control system monitors the position and orientation of each wheel and adjusts steering angles to maintain proper kinematic relationships. This feedback mechanism ensures that when front and back steering are used simultaneously, all tires converge to the same center of rotation, preventing tire-walk-off conditions while maintaining enhanced maneuverability.
Solution Approach 2:
The patent changes the control parameters from fixed geometric steering relationships to dynamically adjusted steering angles for each wheel. By independently controlling the steering angle of each wheel assembly based on real-time position data, the system can maintain proper turning geometry even when using both front and back steering mechanisms, ensuring all tires follow concentric radial paths to a common center.
4Temperature
If excessive flexing of tires occurs during movement, then heat is produced which can cause tire failure, but reducing tire flexibility reduces comfort and stability
Solution Approach 1:
The patent replaces the mechanical hydraulic steering system with an electric propulsion and steering system. This substitution provides more precise and gentle control of the rig, reducing sudden movements and vibrations that cause excessive tire flexing. The electric motors with gearboxes provide smooth torque delivery and controlled acceleration, minimizing dynamic loads on the tires while maintaining their necessary flexibility for comfort and stability.
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
Enables precise directional control and reduced tire scrub, minimizing the risk of environmental spills and improving maneuverability, while reducing hydraulic fluid usage and heat-related tire failures.
Implementation Method 1
8 AC electric motors driving 8 right angle gearboxes built into the trunnions
Implementation Method 2
planetary gearboxes which are bolted to the rims thus driving the 8 rim and tire assemblies
Implementation Method 3
double-ended steering cylinder mechanism for improved steering geometry
Data Source
AI summary
A drill rig with a steering system may include a substructure having a wheelhouse, a drill floor arranged atop the substructure, a mast extending upwardly and above the drill floor, and a steering system arranged within the wheelhouse. The steering system may include a wheel assembly comprising an electric motor configured for driving rotational motion of a wheel, a deployment device configuring for deploying the wheel assembly to carry the drill rig, and a steering mechanism configured for selective engagement with the wheel assembly and rotating the wheel assembly.