The primary goals of this week are to create fully functioning SCP actuators and develop the design for the integration of the SCP actuators within the printable robotic gripper. Thus far, Wenzhong, Devon, Anthony, and I have developed a setup for twist insertion which consists of a servo motor, the DC power source, weights, and the polymer thread. The twist insertion process has been an overall success; however, there appear to be certain spots within the thread in which overtwisting has occurred. The use of a stepper motor could resolve this issue as it would ensure only a certain number of twists are inserted. Another potential solution may be simply timing how long the servo motor has been running for. The length of the string is known, the RPM of the servo is also known; thus, the time that the servo must run for for the coils to be inserted could be calculated. The annealing process is proving to be a greater obstacle. The exact voltage that must be applied in order for the actuators to be annealed is unknown. The melting temperature of the thread is 250; however, the reported value for the temperature that the actuators must reach is 1501. The main goal for this week is calculating the exact value and testing the annealing process with this value.
Next week the goals will be create actuators of different lengths and using the microcontroller to control the annealing process. I also will attach the working actuators to the gripper.
[1] Yip, M. C. and Niemeyer, G., “High -performance robotic muscles from conductive nylon sewing thread,” IEEE International conference on robotics and automation, 2313-2318 (2015).