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.

In this study, we developed a selective driving joint forceps (SDJF) for laparoscopic surgery. The SDJF has a mechanism that the driving joints can be selected arbitrarily, therefore each joint doesn't require an individual actuator for operating. The developed SDJF has six joints that can be operated using only four actuators. Each joint has 2-degrees-of-freedom (DOF) of flexion. Therefore, the SDJF has the same working area as the forceps having six driving joints (each joints can bend ±30° around the X and Y axes). The mechanism of the SDJF is realized by fixing each joint with a collar made of shape memory polymer. The proposed mechanism not only reduces the number of actuators required for joint operation, but also has the rigidity of the forceps, which is important in surgery. In addition, a driving section of the forceps is driven by pneumatic cylinders, therefore, the forceps joint has high-back-drivability, lightweight and high-output. We measured the heating and cooling time required to change the driving joint, dynamic response and rigidity of the prototype SDJF.

In this study, a robotic forceps with a wrist joint using visual SLAM for joint angle sensing was developed. The forceps has a flexible joint connected to the wrist joint at its rear end and the motion of the rear joint is driven by a parallel linkage. A monocular camera attached on the rear of the parallel linkage is in charge of position sensing, and the joint angles are estimated from the pose of the camera. The pose of the camera is obtained by a visual SLAM. The visual servo system realizes a simple attaching mechanism. The static and dynamic positioning experiments are conducted. We confirmed that the visual servoing system controls the forceps tip within the error of 3 deg in the motion range of 50 deg.

A method to improve quality of life of elderly people is to increase muscle strength. The purpose of this study is to develop a machine to improve muscle strength effectively. In this paper, we proposed a muscle strength training machine that exerts variable resistance using pneumatic artificial rubber muscle. In addition, we observed the effect on muscle activity by using the proposed machine with predictable and unpredictable load change patterns. Experimental results showed that there was a difference between the rising time of muscle activity and the maximum amplitude of electromyogram depending on predictability of the load change and showed the possibility of effective muscle strength improvement against unpredictable load using the arm curl machine.

Motor skill learning is fundamental in many physical activities of human. In the processes of learning of motor skills, learners often receive visual or physical information about postures from teachers. However, the information about postures usually cannot be transmitted precisely. In this paper, we propose a motion teaching system to transmit teachers' motion to learners directly by using a motion capture and an assist suit. The assist suit, which has a pneumatic artificial rubber muscle (PARM) as an actuator, was designed to move a learner's hip joint with less loss of assistive force and less constraint of motion. Hip joint motion of a teacher can be transmitted to the assist suit by master-slave control. In addition, to compensate the delay of the PARM, posture of the teacher is predicted before the occurence by a recurrent neural network by using electromyogram signals and the past joint angle. We confirmed the system can transmit a teacher's motion to a learner in real time, and with the neural network, the delay of the learner's motion could be suppressed to approximately 0.1s, which is enough to feel visual and physical information synchronous. Therefore, the proposed motion teaching system would have the ability to transmit teachers' motion to learners visually and physically with precision sufficient to facilitate skill transmission.

This paper proposes a particular case of a robot body design method which determines a degrees of freedom (DOFs) number and link parameters to maximize a target task performance. The DOFs number is an essential point to be considered in the robot body design problem. In this paper, the target task is to make a long throw, and multi DOFs ball throwing robot is designed. Design parameters are the robot body parameters and its motion pattern, and they are designed to maximize ball flying distance under long throw task conditions. To define the link lengths and the robot DOFs number as design parameters, it is assumed that intermediate links of the robot have identical actuators, and these link parameters are defined as functions of link lengths. These links are chained to construct the whole link system. Because of this assumption, the motion equation, which is utilized in the task conditions, is determined by the given robot DOFs number and link lengths. The proposed method was applied to the ball throwing robot model, and its body parameters and motion pattern were designed in the proposed calculation algorithm. As a result, 5 DOFs robot and its throwing motion were obtained, and the ball flying distance was maximized. The ball flying distance was changed along with the DOFs number, and the effectiveness of the proposed design method was demonstrated.

This paper proposes an off-line periodic motion pattern design method using dimensional reduction. A human periodic motion is measured by a motion capture system, and it is projected onto a low dimensional space based on principal component analysis. The low dimensional motion pattern is modified, so that the high dimensional motion pattern satisfies the motion conditions, dynamical consistency and joint angle and torque limitations. The proposed method is applied to the motion pattern design of the planar bipedal robot. The moon-walk performed by a human is transformed to the robot motion. In this case, the motion conditions are the kinematic closed loop condition and the ground contact states of foot links. The floor reaction force condition and the satisfaction of the motion equation are given for dynamical consistency.