This project develops a method for the design of linkages which allows for determining the linkage dimensions directly from specifications on the applied or transmitted forces and moments. Linkages form the basis of many mechanical systems. They may have either closed chain or open chain (a robot) configurations, and may require multiple actuators to simultaneously control several independent degrees of freedom. It has become standard practice to design linkages with position, velocity, and acceleration requirements as the foremost criteria in determining linkage kinematic parameters. In contrast to the primacy of position based design, force is usually considered secondarily after the kinematic geometry is determined, and is used to size actuators or structural and transmission members. This research develops the theory for force based design which allows forces and moments to be taken into account in a more direct manner and earlier in the design process than heretofore possible. In addition to leading to an expanded kinematic theory, the results should lead to more efficient and optimized designs. In summary, the research goal is as follows: given a requirement for prescribed wrenches (a system of force and moment) to be applied at prescribed points in space, develop a systematic procedure for determining the dimensions of all linkages of a given type and structure which will satisfy the requirements. The project comprises five topics including dimensional synthesis of open chain linkages to match wrench specifications, dimensional synthesis of closed loop linkages to match wrench specifications, design for incompletely specified wrenches (when not all six wrench parameters need to be specified), design for combined motion-wrench constraints, and design of linkages with springs or dynamic effects to match wrench constraints. This work should lead to new approaches to mechanical design which supplement and enhance traditional position based methods.
