Pantograph mechanism for conversion from swelling into contraction motion of pneumatic balloon actuator

This paper proposes a pantograph mechanism to convert swelling motion of pneumatic balloon actuator (hereafter PBA) into linear contraction motion. PBA swells in nature by internal pressurization. Bending PBA, which was previously proposed, converts swelling into bending motion by bimorph mechanism. In addition, we reported conversion from bending motion of PBA into contraction elsewhere. This paper presents direct conversion from swelling motion into contraction by a pantograph mechanism. Direct conversion improves conversion efficiency and performance of actuator. A developed single actuator could achieve efficient conversion and generate 1.2N at 80kPa in the case of 6mm×6mm×400μm device (5mm×5mm balloon). Design for outputs accumulation is also demonstrated. Medical forceps and endoscope are demonstrated as promising medical application of the contracting motion PBA.