Reconstruction Designs of the Automata in the Ancient Korean Water Clock “Heumgyeonggaknu”

Heumgyeonggaknu (Clock of Respectable Veneration Pavilion) is a Korean water clock made by Jang Yeong-Sil in 1438. Based on astronomical observation, the functions of this water clock include time-keeping through a water wheel and telling the hours through many automata puppets set on the five floors of an artificial mountain. However, this device was not preserved. Although the external appearance and the functions are described in ancient literature, the internal structure is unknown. Based on the development of science and technology in ancient Korea, the historical records and the modern restoration designs of Heumgyeonggaknu are surveyed, and the works of timekeeping devices in Korea during the subject's time are discussed. In this study, a systematic design procedure is proposed for reconstructing the ancient mechanisms with unknown parts, and the automata set on the first floor of the Heumgyeonggaknu are taken as a design example. At first, the design specifications of the automata in the device are concluded from the review of historical documents. Then, based on the atlas of generalized chains, specialization is implemented according to design requirements and constraints. All feasible designs that meet the scientific theories and techniques of the subject's time period are synthesized. As a result, two feasible mechanisms are generated for the automata on the first floor. Then, dimensional parameters are designed to meet the required motion, and a computer-aid virtual models is built for simulation. Finally, a prototype of the reconstructed automata is made to verify the movement characteristics and the feasibility of the presented reconstructed designs.