Self-powered difunctional sensors based on sliding contact-electrification and tribovoltaic effects for pneumatic monitoring and controlling

Pneumatic elements such as position and velocity sensors play a vital role in pneumatic monitoring and servo control, which have great demands for integration, multifunction and self-powering. Here we propose an inte-grated triboelectric nanogenerator (TENG) and tribovoltaic nanogenerator (TVNG) in air cylinder as difunctional pneumatic sensor for simultaneous position and velocity monitoring. Based on the sliding contact-electrification between a semicircular PEDOT: PSS film and a circular PTFE polymer, the output voltage of the freestanding -mode TENG can characterize the rotation angle with a resolution superior of 0.02 degrees. While based on the tribo-voltaic effect by the friction between an annular PEDOT: PSS film and a circular aluminum electrode, the output current of TVNG can characterize the rotation angular velocity with a detection limit as low as 1 r/min. With the difunctional sensors, the pneumatic monitoring and high precision servo control of the rotary cylinder is realized within the overshoot of 2% and the control error of 1.5%. This work has provided an active sensing strategy for pneumatic monitoring and demonstrated the great prospects of triboelectric sensor in intelligent pneumatic systems.