A design method for contact contour based on the distribution of target contact pressure

An effective human-machine interface is of utmost importance. However, the current methods for designing contact contours are not entirely flawless, frequently relying on experience and multiple design iterations, and are challenging to achieve the desired distribution of target contact pressure. This study proposes a novel design method for contact contour that is based on the equilibrium relationship under contact conditions and is aimed at achieving target contact pressure. The mechanical properties of human tissue were analyzed, and a finite element model of the human body was established. Using two design cases of a wheelchair cushion and a bicycle saddle, contact pressure distribution was constructed based on design expectations. The deformed surface profile of the human body under the target contact pressure distribution was obtained through simulation. Additionally, the mechanical properties of polyurethane hyper-elastic foam and its variation with model parameters were analyzed, and a mathematical model of it was established. The deformation of foam was calculated and compensated to the deformed body surface according to the target pressure, and the reconstructed contour was then obtained and fitted to the design contour. A control group model was constructed, and contact simulation was used to validate the designed contour. The simulation results of both design cases showed that the difference between the contact pressure distribution of the design contour and the target contact pressure distribution was small, and it was better than the traditional empirical design contour of the control group, thus verifying the feasibility of this method.