DEVELOPMENT OF A LOW-COST WIRELESS SURFACE AND SUBMARINE VEHICLE FOR MONITORING OCEANIC PARAMETERS.

Abstract

Wireless Surface and Submarine Vehicle (WSSV) is a robotic machine that can be used in a wide area for detailed survey and oceanographic data collection. A low-cost WSSV is presented in the present study. The WSSV can adjust its altitude freely by changing the direction of propulsive forces and making the vehicle flexible when moving in the water. In order to achieve the goal of this research, the specific objectives were to design, simulate and develop the control system of the WSSV. Oceanographic sensors and a system for regular tracking of the vehicle were attached to the designed WSSV. The oceanographic sensors were used for measuring oceanic parameters such as sea surface temperature, pressure, salinity, turbidity, ocean depth and communications subsystems. The design, construction and control of the WSSV can be divided into three phases. The first phase involves the design and construction of the WSSV were includes the mechanical system, power system, and body of the vehicle. The second phase involves the system identification using an incorporated Global Positioning System (GPS) for the remote control, simulating the parameters for tracking and positioning control of the vehicle with onboard sensors and software. The third phase involves the design and construction of surface and underwater sensors for sea surface and underwater temperature, turbidity, salinity, depth, and data logger for data averaging and archiving. The materials used to construct a low-cost WSSV are commercial grade polyvinyl chloride (PVC) pipes. The designed vehicle has 9 Degrees of Freedom (9DOF) for motion simulator control using rotational matrices. The designed sensors for surface and underwater vehicles consist of four electronics units: the power, input (sensor), gain (amplifies the output signal), and output units. Each unit/block utilizes various low-power integrated circuits. The design analysis and simulation were carried out using SOLIDWorks CAD software. The stress analysis and deformation zone were obtained for surface and underwater condition, conceding the pressure acting on the WSSV and the results were: the maximum bending action point on the WSSV are 0.414 mm, the maximum and minimum forces action point on Fx and Fy directions of the WSSV were 35.58 N and -38.03 N for Fx and 58.27 N and -20.99 N for Fy the maximum and minimum of moment forces action on the WSSV Mx, My and Mz directions on WSSV were 4156 Nmm and -3881 Nmm, 5708 Nmm and -3709 Nmm and 2777 Nmm and -1900 Nmm respectively, the maximum and minimum of normal stress Smax and Smin acting on the WSSV were between -0.36 MPa and 18.26 MPa and between -18.55 MPa and 0.01 MPa respectively, the maximum and minimum of bending stress Smax (Mx), Smin (Mx) and Smin (My) acting on the WSSV were between 0 Mpa to 7.757 Mpa, between -7.757 MPa and 0 MPa and between -10.65 MPa and 0 MPa respectively, the maximum and minimum of axial stress (Saxial) and Torsianal Stress (T) acting on the WSSV were between -0.4805 Mpa and 0.1731 Mpa and between -2.592 MPa and 1.773 MPa respectively, the maximum and minimum of shear stress Ty and Tx acting on the WSSV were between -0.5755 Mpa and 0.673 MPa and between -0.5827 MPa and 0.6227 MPa respectively, the deformation of stress analysis at the bottom of the WSSV were between 2.947e+001 N/m2 and 6.524e+006 N/m2 respectively, the deformation of stress analysis towards the back of the WSSV were between 2.947e+001 N/m2 and 6.524e+006 N/m2 respectively, the stress analysis at 100m for the WSSV below the water surface were between 1.019e+001 N/m2 and 7.290e+006 N/m2 respectively and the strain analysis at 100m for the WSSV below the water surface were between 5.772e-009 N/m2 and 2.124e-003 N/m2 respectively. The calibration equations for constructed turbidity, salinity and temperature sensors were 6.2487e0.8864 v/g/l, 1055.6exp-1.062 ml/mg/volt and 0.0872x oC/mv respectively. The correlation coefficient (r) result for constructed turbidity, salinity and temperature sensors were 0.9938, 0.9795 and 0.9818 respectively. The performance and the coefficient of efficiency of the constructed sensor were compared with a standard sensor, showing the Mean Bias Error (MBE) result for constructed turbidity, salinity and temperature sensors were 0.003836 g/l, -2.105564 ml/mg and 0.000012 OC respectively, Root Mean Square Error (RMSE) result for constructed turbidity, salinity and temperature sensors were 21.53173 g/l, 145.8701 ml/mg and 0.000557 OC respectively, and Standard Deviation result for constructed turbidity, salinity and temperature sensors were 16.8282, 673.501 and 0.06 respectively, the error margins were relatively small, indicating an excellent performance by the sensor. However, the negative MBE for the salinity sensor was suggested a slight underestimation of the standard. Conclusively, the sensor is efficient in hydro-meteorological studies, capable of monitoring solution conductivity and measuring salinity (and total dissolved salt) in the ocean or brackish water. In conclusion, the developed WSSV and oceanographic sensors are viable and have ready for field deployment.