Ride comfort of patient transport robot chassis

The ride comfort is a significant property of patient transport robots, which is directly related to the performance of rescue instruments and the cause of secondary damage. Previous studies overlook the design optimization of patient transport robots to improve ride comfort in hospital environments. This study designs a mobility system with an improved chassis that enables a more comfortable ride for patients. The system incorporates a longitudinal arm-independent suspension, which has a regulating device that changes the shock absorber angle and longitudinal arm length. A four-wheel vibration coupling response model of the robot vehicle is established. An optimization model with variable stiffness and damping coefficients is built and analyzed. The effective and maximum values of the body's vertical, pitch angular, and roll angular accelerations are used as evaluation criteria of the robot's ride comfort, which is analyzed on random roads and roadblocks, comparing its performance before and after the optimization. The results show that the weighted acceleration of the optimized body reduces by 61.9%, and the optimized suspension system improves the overall robot's ride comfort. The evaluation indices of the optimized robot are measured through experiments. The weighted acceleration in the three directions of the optimized body is 0.18m/s(2), which is less than 0.315m/s(2) as required by ISO 2631-1, indicating that the patient does not feel uncomfortable, rendering an excellent evaluation, and verifying the rationality of the suspension system modeling analysis. The establishment of the multi-objective optimization model provides a theoretical basis for improving the ride comfort of mobile robots.