Automotive Seat Cushion Research Articles

Validation of a Nonlinear Automotive Seat Cushion Vibration Model

SUMMARY A low-order, lumped parameter model is proposed to describe the vertical vibration compliance of an automotive seat. The model includes nonlinear stiffness and damping effects that mimic the properties exhibited by open cell foams that are commonly used in the construction of an automotive seat cushion. A shaped sandbag was positioned on a seat cushion and vibrated to obtain test data. White noise acceleration with amplitude ranging from 0.05 g rms to 0.45 g rms in increments of 0.05 g rms was used to excite the seat track. A luxury car seat and a sports car seat were tested and a nonlinear seat model was identified that predicts the actual test data with fidelity. The paper demonstrates that once a family of model parameters is identified for a particular seat, then the model can be used for a wide spectrum of seat track inputs. Additional experiments also verified that when the sandbag mass was increased by as much as 50%, the predicted response using the proposed model was in agreement with the measured response. Finally, the paper reports the result of an experiment using a human subject on a seat cushion. A simulation using the new cushion model and an ISO vibration model of a seated human produced response data that was very similar to the actual test data.

A flexible automated foam cutting system

Direct cutting of foam has the advantage of greater flexibility and reduced lead time over molding. This paper discusses the design and development of a flexible automated system for foam cutting that utilizes hot-wire cutters. The cutters are moved through the use of a five-axis gantry-type robot system equipped with a tool turret. A method for modeling the cut geometry, based on representing the three-dimensional cut shape as a combination of basic geometrical block shapes, is presented. This method gives the system flexibility to handle different workpiece geometries. A technique for generating the required cutting paths from the modeled geometry is also shown. The developed methodology was applied for the cutting of automotive seat cushions. The results show that the automated system significantly reduces the cutting time and produces cuts of improved quality.