Robotic Propulsion Technology Jonathan Greening Chief Engineer SMD Remote & Autonomous Systems Subsea UK Underwater Robotics Conference 2020
Robotic Propulsion TechnologyJonathan Greening
Chief Engineer SMD Remote & Autonomous Systems
Subsea UK Underwater Robotics Conference 2020
Next Generation ROV Technology from SMD
Objectives:
• Lower OPEX cost
• Improved Reliability
• Higher Performance
• Easier of Use
• Flexibility
Why Electric Propulsion?
• Efficient - Significantly more efficient than hydraulic
• Reliable - Fewer moving parts; less leak paths
• Cheap to Operate - Lower fuel consumption and no start up in-rush (so smaller gen sets)
• Controllable - Better control over speed & torque
Delivering the Power – DC Transmission
• Reliable - AC-DC Surface System• Efficient - no reactive losses• Flexible - shared infrastructure - HV DC bus• Lightweight – smaller umbilical's
Developed with our parent company
CRRC Times Electric
Industry First – Subsea DC/DC ConverterStepping the DC HV transmission down to the vehicle bus voltage was one of the most difficult tasks.
• Power electronics - no large and heavy transformers
• Compact and lightweight - works in oil under pressure
• Reliable - quick change modular units give redundancy
• Flexible - DC vehicle bus at 680V allows• Umbilical connection • Battery connection• Hybrid Umbilical/Battery connection
Maximising Power into the Water
All-in-one modular thruster:• Built-in drive control unit• Built-in compensation
High thrust:• Class leading bollard pull• Power across the vehicle
speed spectrum
Reliable:• Magnetically coupled gearbox• No meshing gears• No shaft seal, typically
the weakest point of any thruster
• Optimised motor efficiency
Vehicle PerformanceA compact power system gives our Electric Quantum a 20% smaller footprint than existing ROVs
Higher power from smaller thrusters delivers un-rivalled power into the water:
• 1250kgf horizontal bollard pull• 1500kgf vertical bollard pull
The result is, Electric Quantum will work in higher currents than any other work class ROV, travelling at speeds up to:
• 4.5 knots forwards• 3.5 knots laterally
AND carry out heavy lift duties up to 1.5 tonnes
A look at Efficiency Electric Quantum vs Hydraulic ROV - 150kW (200hp)
If power into the water is pegged to hydraulic ROV for comparison…
The power required at the surface is:• Hydraulic – 254kW• Electric - 158kW
The overall efficiencies are:• Hydraulic – 40%• Electric – 64%
The fuel use to generate the electricity for EROV is 38% less
In addition, the generator set on a hydraulic ROV is sized to cope with in-rush current of an induction motor – typically needing a 800kVA gen set. The Electric Quantum will work with only 400kVA
Extra performance - the electric Quantum has more power available. Up to 143kW at the propellers!
Testing, Testing, TestingReliability - A priority for every operator.
Multi-Level:• Component:
• Performance• Load• Environmental
• Sub-System:• Power System• Control System• Safety System
• Vehicle:• Control Tuning• Performance
Testing programme:• Performance mapping• Endurance testing• Life - fatigue testing
Advanced Flight System
Cascade control, simultaneous rate and
position
Power Management
3rd Party interface
Dynamic PID
Online calibration for controller parameters
Control based on scenarios
Precise control in high currents
Switchable modes of operation
Avoid saturation,
Move power to where needed
Take Commands from other sources
Auto-tune
Advanced Flight Control Improved response, robust
What does this mean for clients?
Higher performance – Increase the up time of a wind turbine installation vessel by 38%
More Efficient – Kinder to environment and save $200k / year on fuel costs
High Reliability – required for Over Horizon and Un-crewed Surface Vessels operations
Advanced flight System - improves stability, quality of data and quality of operation
Questions?