Shogo Yonekura

Detection of Weak Signals by Emotion-Derived Stochastic Resonance

This paper reports a new finding on functionalities of trembling, the bodily manifestation of fear and joy. We consider trembling of a physically-simulated agent consisting of a vision system and a neural system. It is demonstrated that the noise to visual streams generated by trembling enhances signal to noise ratio of the neural system.

Emergence of multiple sensory-motor response patterns from cooperating bursting neurons

In this paper, characteristics of a sensory-motor system driven by coupled bursting neurons are examined. We constructed a sensory-motor system by connecting networks of coupled bursting neurons. Mutually connected networks showed several kinds of oscillation rhythms. When networks oscillate at 5-10 Hz, a robot pushed an object in an environment, and when networks oscillate at 20-50 Hz, a robot avoided an object. Spontaneous transition between these rhythms was observed, and was clarified to be an emergent property based on cooperative phenomena of bursting neurons. These studies may provide a basis for utilization of coupled bursting neurons and its primitive applications.

Bodily motion fluctuation improves reaching success rate in a neurophysical agent via geometric-stochastic resonance

Organisms generate a variety of noise types, including neural noise, sensory noise, and noise resulting from fluctuations associated with movement. Sensory and neural noises are known to induce stochastic resonance (SR), which improves information transfer to the subjects control systems, including the brain. As a consequence, sensory and neural noise provide behavioral benefits, such as stabilization of posture and enhancement of feeding efficiency. In contrast, the benefits of fluctuations in the movements of a biological system remain largely unclear. Here, we describe a novel type of noise-induced order (NIO) that is realized by actively exploiting the motion fluctuations of an embodied system. In particular, we describe the theoretical analysis of a feedback-controlled embodied agent system that has a geometric end-effector. Furthermore, through several numerical simulations we demonstrate that the ratio of successful reaches to goal positions and capture of moving targets are improved by the exploitation of motion fluctuations. We report that reaching success rate improvement (RSRI) is based on the interaction of the geometric size of an end-effector, the agents motion fluctuations, and the desired motion frequency. Therefore, RSRI is a geometrically induced SR-like phenomenon. We also report an interesting result obtained through numerical simulations indicating that the agents neural and motion noise must be optimized to match the prey’s motion noise in order to maximize the capture rate. Our study provides a new understanding of body motion fluctuations, as they were found to be the active noise sources for a behavioral NIO.

Erratum: Growth of stochastic resonance in neuronal ensembles with the input signal intensity [Phys. Rev. E 86, 011922 (2012)].

The effective noise intensity D that is used to evaluate theoretical value of 〈C1〉 throughout the original paper is inaccurate. In Sec. III A, we derived the piecewise-linear FitzHugh-Nagumo (plFHN) neuron model, and we introduced the noise scaling ξ (t) → 7τξ (t̃) in correspondence with the time scaling t → 7τ t̃ . However, the noise should be scaled as ξ (t) → √7τξ (t̃). Therefore, the plFHN neuron mode I in Eq. (6) and (A1) should read

Super thin 3D form display for multimodal user experiences using vertically deformation of leaf spring and SMA

In this paper, we present super-thin 3D form display as visual and haptics multimodal interface. In contrast to the existing 3D form displays and surfaces requiring huge and complicated system, we developed super-thin 3D form display. We achieved its thickness by using our proposed flat mechanical system that consists of a SMA-coil and a single leaf spring. The thickness of this system is below 1.0 mm and this system can generate 30.0 mm stroke. Furthermore, it can lift an object of 50 g at 30.0 mm and can withstand 100 g load at the top. This super-thin 3D form display using this system has no precedent and is expected to be used for entertainment and digital signage. In addition to this, our proposed flat system provides a basis for the future ubiquitous and portable mechanical man-machine interfaces.

1-DOF spherical mobile robot that can generate two motions

A spherical mobile robot has been developed with a 1-DOF mechanism that can generate two motions, translational and rotational, using only one motor. The basic concept is to attach vinyl strips to the sphere at regular intervals and to change the driving modes of the motor to produce the desired motion. For example, placing the motor in vibration mode causes the trajectory of the contact point between the sphere and ground to follow a specified closed path, such as an elliptical path, which makes the sphere rotate against the ground. Testing of this concept using a self-developed simulator confirmed that rotational motion is generated by the interactions between the surface attachments and the ground. On the basis of these results, a prototype spherical mobile robot was developed, and testing confirmed that switching the motor driving mode generated two different motions.

Development of emotional tremor-based vision system

We aim to investigate biological function of emotional bodily movements while building a robot in the sense of survival. In this particular paper, we build a novel active vision system which detects weak signals by generating tremor actively. Proposed active vision system consists of a noise generator and a neural system. As a noise generator, we use motors with a decentered weight. And as a neural system in order to detect visual signals, we use ensemble of FitzHugh-Nagumo neurons. We first show that our robotic platform can generate several kinds of tremors; tremor around 40 Hz, 50Hz, and tremor which does not involve specific peak in its power spectrum. And, in order to evaluate the effect of tremor, we prepare clear-films as visual stimuli which move aperiodically in a dark environment. We show that as a result of sensory noise induced by tremor, and as a result of stochastic resonance, neural system successfully detects movements of clear films.

Multiple Behaviors Generation by 1 D.O.F. Mobile Robot

In this research, we developed a sphere-shaped mobile robot that can generate multiple behaviors by using only one motor. The robot can generate the translational motion and the rotational motion by controlling the motion of the motor. The motor itself acts as an eccentric weight during motions. To generate emergent behaviors, many protrusions are mounted on the surface of the spherical body. The emergent behaviors occur by an interaction between the external world and these protrusions when the sphere is vibrating, and the robot can move in a random walk manner.

Development of swing-slip locomotion for no-legged primevaloids

In this paper, synthetic research for primevaloids, robots of primitive appearance, is described. First, we briefly introduce goals of the project within a perspective of entertainment robotics. Next, we sketch design concepts and prospective principles for a novel kind of entertainment robots, while placing our emphasis on primeval appearance, survivability, and emotions. Then, after introducing several appearance designs of a robot, we shift our focus to a locomotor for them. After we simplified their appearances into a skeletal model, we implement a simple embodied agent within a physical simulation. Using the physical simulation, we test the validity of the locomotion model, and analyze basic behaviors of the agent. We also test swing-slip locomotion within the real-world. It is shown that swinging creaturepsilas head leads to stable locomotion.