Master of Science

thesisLegs are found to be a better mode of locomotion than wheels when it comes to mobile robots traversing on rough terrains. However, maintaining the stability of a legged robot while it moves is a big factor in the development and use of these machines. Studies conducted on legged robots show that the choice of leg-configuration and directional compliance can influence the stability of a robot. Research has also shown that the stability of a robot can be improved by controlling the compliance of the robot's legs. The goal of this research has been to develop a robot leg and show that variable compliance in the leg can be achieved using a pneumatic cylinder. First, a mathematical model of a pneumatic cylinder is made and validated through experiments. A leg is then designed and fabricated with the pneumatic cylinder as its variable compliant member while considering the directional compliance of the leg. A mathematical model of the whole leg along with the pneumatic cylinder's model is then made. An experiment is conducted to observe the behavior of the fabricated leg using a robot manipulator and the mathematical model of the leg is validated. Results obtained from the experiment and the leg's model indicate that the ground reaction force and the compliance of the leg can be modulated by changing the initial air pressure in the pneumatic cylinder and by varying the knee angle of the leg