A legged vehicle is potentially more energy efficient and mobile than conventional vehicles in rough terrain. The performance of such a legged vehicle is strongly dependent on the leg geometry. In general, a leg linkage which possesses three-degree-of-freedom foot motion is adequate. A preliminary design of the leg with a view to good energy efficiency resulted in a four-bar leg. This was described by S. M. Song et al.[Mech. Mach. Theory19, 17–24 (1984)]. In the present paper, the mobility of the legged vehicle is brought into consideration in the leg design. A study of the mobility of a six-legged vehicle shows that a large walking envelope is required for each leg linkage. In order to satisfy this requirement, the original four-bar leg was modified into a seven-bar leg by mounting another four-bar linkage on the coupler of the original four-bar linkage. Also, a different type of leg linkage based on pantograph mechanism was designed. A comparison of the leg performance of both types of leg is made in this paper and the pantograph leg is found to be more effective.
Mechanism and Machine Theory
Song, Shin-Min; Waldron, Kenneth J.; Kinzel, Gary L. (1985). Computer-Aided Geometric Design of Legs for a Walking Vehicle. Mechanism and Machine Theory 20(6) 587-596. doi: 10.1016/0094-114X(85)90075-8. Retrieved from https://oaks.kent.edu/caestpubs/33