The history of walking machines is a surprisingly long and detailed one. Early sketches and designs can be traced as far back as the 18th century. Towards the end of the 19th century more ambitious designs began to surface with the first biped (two-legged) walking machine designed in 1893 by Georges Moore. Further designs arose around this time covering quadruped walking machines, which were little more than trucks with legs. The earliest walking machine to make it off the drawing board was the Millipede, developed during the first World War, and was a walking machine based on the modification of wheels and chains.
The breakthrough development in the history of walking robots came in 1966, when Phoney, the first computer-controlled walking machine was created by Mcgee and Frank at the university of South Carolina.
The first manual controlled walking truck was the GEE Quadruped, General Electric Walking Truck by R. Mosher. The project was finished in 1968. More complex walking machines began to occur in the '70s with a number of six-legged walking machines being built. The level of complexity developed from early models occurring around 1973 to fairly sophisticated models like the Titan models of the '80s. Whereas all previous legged walkers had concentrated on getting the walking action right, the Titan III model took things a step further and incorporated whisker sensors and a processing system on the feet, to determine the status of the ground. The Titan IV model debuted in 1985, and was a faster model, able to display a variety of different walking patterns. Three prototypes of this model were made by Mitsubishi industries, one running autonomously, with an onboard computer and batteries. Developments in robots with more than two legs continues to the day with emphasis being placed upon advanced navigation methods and increased strength and speed.
Development in robots with two legs occurred in much the same way as those with more legs, with the first working models begging to appear at the end of the '60s. Early bipeds had to be connected to large computational devices, with early models like the 1969 Wap-1, designed by Ichiro Kato using computers to alter artificial muscles connected to a twin-legged frame. In 1970 and 1971 Wap-2 and Wap-3 followed, with Wap-3 able to move its center of gravity on the frontal plane so that it was able to not only walk on a flat surface but also descend and ascend a staircase or slope and turn while walking. The three dimensional walking and turning that Wap-3 achieved was the first in the world. It was directed by a controller-based memory.
Kato went on to develop numerous other biped machines, and is regarded as a one of the main pioneers in the biped sector. In 1973 Kato led a project to construct a human-like robot. Wabot I was developed, and was the first full-scale anthropomorphic robot in the world. It was highly sophisticated, consisting of a limb control system, a vision system and a conversation system. It was estimated that it had the mental ability of a one and a half year old child. Kato developed a variety of further robots in the '80s, robots including in 1980 one which realised quasi-dynamic walking for the first time in the world. The model WL-9DR, used a 16-bit microcomputer as its controller rather than a mini computer, allowing for increased versatility. In 1985 Kato and his group developed a new robot that could descend stairs and slight inclines. This is far harder to do with a biped than quadrupeds because of the decreased stability and complex balance issues. In 1989 Kato and his group developed a walking control method (implemented in the WL-12RIII) which enables stable walking under unknown external forces and moments by using "co-operation motion of a trunk and lower limbs". This enabled increased speed of movement whilst ascending or descending stairs because of the added stability that this new system provided.
As time progressed into the '90s a man named Raibert in 1991 managed to get a 3D biped to travel round a laboratory, and in 1992 Playter managed to make a 3D biped somersault.
There are a wide variety of other walking robots and other developments but these are the most important ones to date. The current emphasis now centres around commercial and industrial applications of walking machines, and the necessary improvements needed to provide robots able to perform valid actions in commercial and industrial environments. Most of the innovation in the walking robots sector occurs in Japan.
Run The Planet thanks the Robots That Walk website for the permission to reprint the article "History of walking robots" by Thomas Isaac. Text © by Thomas Isaac. Illustration © 2004 by Run The Planet.
