Publication Date


Document Type


Committee Members

Zach Fuchs (Committee Member), Luther Palmer, III. (Advisor), Xiaodong Zhang (Committee Member)

Degree Name

Master of Science in Electrical Engineering (MSEE)


For purposes of travelling on all-terrains surfaces that are both uneven and discontinuous, legged robots have upper-hand over wheeled and tracked vehicles. The robot used in this thesis is a simulated hexapod with 3 degrees of freedom per leg. The main aim is to reduce the energy consumption of the system during walking by attaching a passive linear spring to each leg which will aid the motors and reduce the torque required while walking. Firstly, the ideal stiffness and location or the coordinates for mounting the spring is found out using gradient based algorithm called `Simultaneous Perturbation and Stochastic Approximation Algorithm' (SPSA) on a flat terrain using data from a single walking step. Motor load is approximated by computing the torque impulse, which is the summation of the absolute value of the torque output for each joint during walking. Once the ideal spring and mount is found, the motor loading of the robot with the spring attached is observed and compared on three different terrains with the original loading without the spring. The analysis is made on a single middle leg of the robot, which is known to support the highest load when the alternating tripod gait is used. The obtained spring and mounting locations are applied to other legs to compute the overall energy savings of the system. Through this work, the torque impulse was decreased by 14 % on uneven terrain.

Page Count


Department or Program

Department of Electrical Engineering

Year Degree Awarded


Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.