08 Aug

Weekly update 08/08

Wenzhong Yan [[ Internal only ]]

last week, I focused on the mechianism, parameter setting of annealing process of SCP actuator and mechanical logic design for autonomous paper robot.

For the mechanism of annealing process, the key step is to relax the stress of polymer after coil insertion. So we need to heat the polymer up above its glass transition temperature(Tg, about 70℃ for Nylon 6,6) to evoke plastic elongation. Thus, the final torque-balanced structure of actuator can be set. Usually, when using Joule heating with pulse square voltage, the peak annealing temperature is set as 150℃, much higher than Tg but below melting point(Tm, about 250℃ for Nylon 6,6). In this manner, the stress in the actuator could be released to a great extent. Also, the actuation range is built up for subsequent operation. Hence, in our experiment, we will use pulse square voltage to anneal the actuator, and set the peak temperature as 150℃ for each annealing cycle for 20 times. The parameters we need to decide are voltage and on/off ratio of pulse square voltage according to the annealing peak temperature.

On the other hand, the first version of mechanical logic was designed. The mechanical logic is compose of origami frame and SCP actuator. The SCP actuator functions as conductor and also as actuator to switch the switch. Hopely, I can finish the first demo by next week.

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