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Page 360 Sun et al. Intell Robot 2022;2(4):355­70 I http://dx.doi.org/10.20517/ir.2022.23

Figure 6. Frame structure diagram of the rescue ROV.

the acoustic detection system. Photoelectric conversion is adopted between the shore-based control part and
the ROV body, and reliable communication is carried out through wired photoelectric composite cable.

3. HARDWARE DESIGN OF OFFSHORE UNDERWATER SEARCH AND RESCUE ROV
The hardware part of the ROV mainly includes UPE frame, upper shell, thruster, integrated control cabin,
power supply cabin, floating material, counterweight, load-bearing photoelectric composite cable (including
cable retracting and releasing disc device), etc. The UPE frame is the load-bearing support of the whole ROV
body, connecting and fixing each module together. The vertical thruster is mainly used to complete the diving
and floating movement of the equipment, and the horizontal thruster is mainly used to complete the forward
and lateral movement of the equipment. The integrated control cabin is mainly equipped with ROV control-
related equipment. The power cabin mainly supplies power to each module of the equipment and has the
function of independent ROV power switching to reduce the self-noise of acoustic detection. The counter-
weight and floating material are mainly used to adjust equipment balance and stability. The load-bearing
photoelectric composite cable adopts the marine cable standard and belongs to the photoelectric composite
structure, with load-bearing and tensile capacity of more than 400 kg.

3.1. ROV body framework design
h For the ROV design, structural analysis on the frame-cover structure of ROV should be carried out [11] . The
overall frame of the ROV body is made of UPE with a thickness of 20 mm. The relative density of this material
is lower than that of water (0.923 g/cm ), with good heat and cold resistance, good chemical stability, high
3
rigidity and toughness, and good mechanical strength. This solution adopts UPE material, which can not only
improve the total buoyancy of the whole robot but also ensure its stiffness stability. At the same time, the high
toughness of the material can provide a certain anti-collision ability. Its structural design is shown in Figure 6.

Since the force of the search and rescue ROV mainly acts on the main bearing plate, especially when the robot
is hoisted, here, only the relevant finite element stress analysis of the upper bearing plate is carried out, and
the static analysis software built in CATIA is used for analysis (see Figure 7). Figure 7 shows an example of
the tensile force on the upper shell when the robot is hoisted. Figure 8 shows the stress–strain diagram of the
frame structure. It can be seen in the figure that the design meets the allowable deformation requirements.