One of the recent developments in physical reservoir computing, which uses the complex dynamics of a physical system as a computational resource, is the use of a pneumatic pipeline system as a computational resource. This uses the dynamics of air for computation, and because it is lightweight and power-saving, it is used for gait-assist control using a soft exoskeleton with pneumatic rubber artificial muscles. In this study, we verified that by feeding back the estimated information to a pneumatic pipeline system, the pneumatic physical reservoir computing can generate periodic pressure changes as a stable limit cycle, such as those seen in walking. A pneumatic reservoir with feedback loops was modeled to generate limit cycles in the simulation, and it was confirmed that the system could generate limit cycles with high accuracy even from initial positions far from the target limit cycle. This system is expected to be applied to assist walking movements with a soft exoskeleton with a lightweight computational device.

In human physical activity, motion and sensation affect each other. By utilizing this interaction and appropriately controlling and presenting sensory input during exercise with an external device, it is expected that training will become more efficient and exercise performance will improve. This study proposes a novel visual and force sensory stimulus presentation system using a pneumatically driven gait assistive suit and a head-mounted display (HMD). We aim to develop a gait simulator that realizes the same training effect as walking in various environments by presenting designed sensory stimuli with external devices to solve the spatial limitation of gait training. As an application example of the proposed system, the gait assistive suit applies loads to the legs of a subject walking on flat ground, and an HMD is used to show images of the slope climbing, allowing the subject to virtual experience climbing a slope. In the experimental validation, four subjects measured the average muscle load and leg motion trajectory during virtual slope climbing using the proposed system. We compared the above results with other experimental conditions: (i) normal flat ground walking, (ii) normal slope walking, and (iii) walking with force presentation only. As a result, we confirmed that the root mean square of the myoelectric potential at the front thigh for all four subjects approached the result of normal climbing when the proposed system was used.

We developed a novel ophthalmologic surgery robot for needle insertion to assist ophthalmologists. The robot consists of a single-degree-of-freedom injection device with a needle on its tip and an intraocular pressure control device. The device is driven by a pneumatic cylinder and uses the back drivability of the actuator to estimate the needle forces. The insertion force of the needle is estimated from the position and pressure difference of the cylinder. This insertion force is recognized as a trigger to start intraocular pressure control and assist smooth needle insertion medical solution. The pressure is increased by the control of the syringe with a pneumatic cylinder. The operator can manually inject medication after the needle is inserted. The effectiveness of the robot was confirmed with experiments using porcine eyes. The robot can successfully insert the needle when the target intraocular pressure is 2.4kPa.

Wearable gait assistive devices have been im-proved by soft robotics in terms of safety and physical burden of the wearer. Currently, electrical sensors and computers around the wearer are bottlenecks in enhancing the wearer's activities. In this paper, we present a wearable gait assistive system using soft pneumatic system for all the actuation, sensing, and computation. Pneumatic artifical muscles (PAMs) on the thighs were used to generate assistance force, and thin PAMs on the whole legs were used for sensing the wearer's motion. All thin PAMs were connected to each other by tubes, and the pressure response in the tubes were exploited to compute the wearer's motion in manner of physical reservoir computing. The left thigh angular velocity estimated from the reservoir response was used for control the PAMs for actuation. Our experiment with the use of gait assistance showed that the system worked correctly. This paper shows that the pneumatic analog computation system for sensing soft body can help the functionality of soft wearable assistive devices.