Real-Time Control of Cycling in a High-Performance Leg With Series-Elastic Actuation

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The Ohio State University

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A high-performance, lightweight prototype robotic leg using series-elastic actuation was developed in previous work to study the effects of series-elastic actuation in vertical jumping. However, there was also a desire to perform other high-speed dynamic motions with the leg such as cycling. To this end, the thesis goals were focused on improving the existing embedded controller as well as implementing a high-speed cycling function. An analog potentiometer was used to replace a faulty sensor at the knee joint, which houses the compliant element of the series-elastic actuator. Changes were made to the previous controller hardware and software in order to utilize the data available from this new sensor. Using several new functions, a smooth cyclical trajectory was created and followed by the robotic leg at high speeds. The entire cycle was completed in less than 0.5 seconds with a stroke of more than 15cm. These functions will open the path for development of precise trajectory control in future robotic legs, as well as allow for the study of series-elastic actuation through a new dynamic motion. The design of the aforementioned changes and functions are discussed. The significance of the thesis results is discussed, as well as the expected course of future work.


Bachelor of Science with Distinction


legged locomotion, embedded control, series-elastic actuation