Challenge of solving
Underwater Robot Engineering, Consulting, and Optimization
Our client reports that his old underwater robots range which expected to be more than 55 miles are about 35 miles. And its velocity is 6 Knots which is supposed to be 8.5 Knots. These two parameters were nominal and no one can be witnessed that the underwater robot was qualified for when they were new. then the problem was totally vague. The problem was some kind of blind engineering consulting.
Winning the contract
The user had no view about the source of the problem. It was impossible to tests the underwater robot in the field before the contract. He just looks someone to analyses and solves the problem in shortest time and lowest price. Here Lian Innovative entered to the problem by offering shortest time and lowest price just by analyzing the problem not by doing field tests.
Lian Innovative analyzed the system and draw a complete energy transfer line from batteries of the underwater robot to the Hull of the underwater robot.
Each subsystem performance and efficiency tested in the system, and separately to understand assembly problems if there were any. Surprisingly results showed that overall efficiency from battery pack to Hull was less than 23% !!! That was too low for an underwater robot which its energy comes from expensive batteries.
After it, Lian Innovative focused on energy consumption of the hull. At first, the towing test (drag test) in the sea was done. Total drag force was measured in different speeds precisely and carefully.
In the next step, Lian Innovative designed and developed a scaled model of the underwater robot, and did the towing test in the tank.
Field test reports confirmed the underwater robot model test results. It revealed that the drag force is beyond what was expected from theory and analyses. Froud No. and Reynolds No. carefully computed and discovered that the main factor which increases the drag force is Up-welling Fluid.
In synchronous with our client, we decided to change the underwater robot nose shape. Six different standard nose performances were investigated. All of them designed and manufactured to be used on downscaled model.
The drag force of all models in different speeds precisely measured by towing test. Two of them with lowest drag force was selected, and other factors such as manufacturability and maneuverability were carefully investigated and tested.
Results show that proposed underwater robot nose reduces the drag force to 53% of the main nose. That was great!!!
By huge investigation and having experienced consultant engineers, it revealed that the rudder and elevator airfoils and their bases were not optimum in water streamline and have a considerable effect on underwater robot performance. Engineering consultation and training, let the client understand the side effects of the problem. He accepted the problem analyses deeper.
With client acceptance, Lian Innovative developed a newly designed control surfaces and repeat the drag tests by the towing test. Results show that finalized model drag forces were about 32% of the main model. Wonderful!!!
Field Verification Test
To prove our model test results, we need to make two full-scale underwater robot nose prototype and control surfaces, assembled them on the real underwater robot, and repeated the field test with the new configuration. The client didn’t accept to had any modifications on his underwater robot body and structure. Any kind of welding, drilling, and permanent modifications were prohibited. Lots of innovative engineering solutions by Lian Innovative mechanical engineers consultant helped us to find a way to do the test due to client restrictions. Finally filed tests were ran and the results validated model test by error less than 4%. Client accepted to change the nose and hydrodynamic surfaces.
In the next step Lian innovative propose to change old fashion underwater robot thruster, to a new modern high efficiency, low noise PMSM Underwater Thruster. A custom designed enhanced underwater thruster was designed and developed and a prototype was manufactured.
Prototype underwater thruster along with new nose and control surfaces started to be tested in the field for more than 250 hours. Client accepted the whole story. The speed of underwater robot set to be 8.5 Knots as the client ordered. But its range goes up to 75 miles with same batteries !!! that’s because not only the underwater thruster system efficiency raised up to 58% from 23%, But also the hull consumption reduced to 32% of initial value. This wonderful results convinced the client to ordered Lian Innovative to renew 12 of his underwater robots.
Client accepted to apply newly design system to all 12 robots. And we did it proudly!!!