Performance Evaluation of a Multi-Vectored Water-Jet Propellers Device for an Amphibious Spherical Robot

This paper presents a performance evaluation of the multi-vectored water-jet propellers system (MVWPS) for the amphibious spherical robot IV (ASR-IV), which will contribute to the real-time dynamic thrust vectoring of ASR-IV. This work extends the 2D modeling into 3D space, which benefits the 4DoFs control of ASR-IV more. The dynamic modeling (forces and moments) of ASR-IV can be obtained by synthesizing the propulsive vectors of four propellers. Thus, a novel experimental mechanism was developed to evaluate the MVWPS. This mechanism was designed with the mass distribution centered for the robot. Using a six-axis force/torque sensor at the equivalent mass center, we obtained the direct propulsive effect of the system for the robot. Experiments of one propeller were conducted to establish the relationship between the pulse width module (PWM) signal and the thrust. Then, experiments of MVWPS were carried out to evaluate the performance of MVWPS.