For improving the comprehensive driving performance in the gastrointestinal (GI) tract,a new type of petal-shaped capsule robot is proposed. The convergent wedge-like gap is formed between each surface of the four eccentric tiles and the inner pipe wall,which changes the liquid flow path around each of the four convergent wedge-like gaps and generates multiple wedge effects. Based on Couette flow theory and Newton inner friction law,a fluid dynamics model of the petal-shaped capsule robot is derived. According to the analytical solution of swimming speed,hydrodynamic pressure and fluid resistance torsion moment,the comprehensive performance of the petal-shaped capsule robot are investigated. Theoretical and experimental results show that both fluid dynamic pressure and swimming speed of the petal-shaped capsule robot are improved greatly,and fluid resistance torsion moment is reduced significantly. The petal-shaped capsule robot possesses a better comprehensive performance,achieving the non-contact drive and complete suspension in the middle of the pipe,shorter diagnosis time,more weaken fluid resistance torsion moment and safer drive in the GI tract,the petal-shaped capsule robot has a promising application prospect in the GI diagnosis.