Axiomatic Design of Customizable Automotive Suspension
by Deo, Hrishikesh, Suh, Nam P.
June 21, 2004 | Link to full document (172K PDF)
Abstract
The design of existing suspension systems typically involves a compromise solution for the conflicting requirements of comfort and handling. For instance, cars need a soft suspension for better comfort, whereas a stiff suspension leads to better handling. Cars need high ground clearance on rough terrain, whereas a low center of gravity (CG) height is desired for swift cornering and dynamic stability at high speeds. It is advantageous to have low damping for low force transmission to vehicle frame, whereas high damping is desired for fast decay of oscillations. To avoid these trade-offs, we have proposed a novel design for a customizable automotive suspension system with independent control of stiffness, damping and ride-height, which is capable of providing the desired performance depending on user preference, road conditions and maneuvering inputs. A suspension prototype has been built to demonstrate the concept. Axiomatic design theory was used for the development of the concept, design and fabrication of the prototype and design and implementation of the control system for the suspension system. The mechanical design of the proposed system is decoupled with respect to the functional requirements (FRs) of stiffness and ride-height; moreover ride-height is affected by the load on the vehicle (noise factor). A feedback control system for the customizable suspension was designed and implemented to uncouple the system and to make it robust to the noise factor. With this example, feedback control is proposed as a strategy for converting coupled or decoupled designs to uncoupled designs and for achieving robustness to noise factors.
Link to full document (172K PDF)
