Hirozumi Oku

A Millimetre-Sized Robot Realized by a Piezoelectric Impact-Type Rotary Actuator and a Hardware Neuron Model

Micro-robotic systems are increasingly used in medicine and other fields requiring precision engineering. This paper proposes a piezoelectric impact-type rotary actuator and applies it to a millimetre-size robot controlled by a hardware neuron model. The rotary actuator and robot are fabricated by micro-electro-mechanical systems (MEMS) technology. The actuator is composed of multilayer piezoelectric elements. The rotational motion of the rotor is generated by the impact head attached to the piezoelectric element. The millimetre-size robot is fitted with six legs, three on either side of the developed actuator, and can walk on uneven surfaces like an insect. The three leg parts on each side are connected by a linking mechanism. The control system is a hardware neuron model constructed from analogue electronic circuits that mimic the behaviour of biological neurons. The output signal ports of the controller are connected to the multilayer piezoelectric element. This robot system requires no specialized software programs or A/D converters. The rotation speed of the rotary actuator reaches 60 rpm at an applied neuron frequency of 25 kHz during the walking motion. The width, length and height of the robot are 4.0, 4.6 and 3.6 mm, respectively. The motion speed is 180 mm/min.

Neural Networks Integrated Circuit for Biomimetics MEMS Microrobot

In this paper, we will propose the neural networks integrated circuit (NNIC) which is the driving waveform generator of the 4.0, 2.7, 2.5 mm, width, length, height in size biomimetics microelectromechanical systems (MEMS) microrobot. The microrobot was made from silicon wafer fabricated by micro fabrication technology. The mechanical system of the robot was equipped with small size rotary type actuators, link mechanisms and six legs to realize the ant-like switching behavior. The NNIC generates the driving waveform using synchronization phenomena such as biological neural networks. The driving waveform can operate the actuators of the MEMS microrobot directly. Therefore, the NNIC bare chip realizes the robot control without using any software programs or A/D converters. The microrobot performed forward and backward locomotion, and also changes direction by inputting an external single trigger pulse. The locomotion speed of the microrobot was 26.4 mm/min when the step width was 0.88 mm. The power consumption of the system was 250 mWh when the room temperature was 298 K.

Artificial neural circuit integration for MEMS microrobot system

This paper discussed about less than 5mm in size hexapod locomotive type microrobot system. The microrobot system consisted by micro-mechanical systems which were fabricated by micro fabrication technology and micro-electro systems which was constructed by integrated circuit (IC) technology. Micro-mechanical systems were equipped with small size rotary type actuators, body frame, link mechanisms, and 6 legs to realize the ant-like switching behavior. Micro-electro system was the locomotion rhythm generator of the microrobot using artificial neural circuit. Both systems were made from silicon wafer. Therefore, both systems could integrate on same silicon wafer using micro-electro-mechanical systems (MEMS) technology. Artificial neural circuit consisted by 4 cell body models and 12 inhibitory synaptic models. Cell body model was analog circuit model which could output oscillatory patterns such as the biological neuron. Cell body models were connected mutually by the inhibitory synaptic models. Thus, artificial neural circuit could generate the locomotion rhythms using synchronization phenomena of the cell body models such as biological neural networks. Locomotion rhythm generator using artificial neural circuit realized the locomotion of the robot without using any software programs or analog digital converters. As a result, MEMS microrobot performed forward and backward locomotion, and also changes direction by inputting an external single trigger pulse to the artificial neural circuit.

MEMS Microrobot Controlled by Mounted Neural Networks IC with Two Types Actuators

We report the hexapod microrobot controlled by the bare chip IC of hardware neural networks. MEMS (micro electro mechanical systems) technology is used for fabrication of the microrobot. Lead zirconium titanate (PZT) and shape memory alloy (SMA) are used in each actuator, respectively. As the result, PZT type is realized the walking motion by bare chip IC. Moreover, SMA type shows the hexapod walking locomotion with mounted bare chip IC. The walking speed is 2.4mm / min and the step width was 0.083mm.

Development of mountable pulse-type hardware neuron model integrated circuit on MEMS microrobot

This paper proposes a pulse-type hardware neuron model (P-HNM) bare chip integrated circuit (IC). And the developed bare chip IC realizes a mountable size on a millimeter scale robot. The P-HNM is mimicking a neural networks of a brain system of the living organisms. The neural networks receive the information as stimulation from the outside at a cell body through an axon, and then, it work to the outside as the response. As a result, the living organisms can respond to the accidental events. Therefore, the application of the neural networks for industrial fields such as a control system will realize the adaptable respond in the future. In this research, the P-HNM is developed for the robot control. A hardware approach can realize a continuously process and nonlinear operations at high speed. And it is realized the miniaturization by integrating the CMOS IC. The developed IC is constructed by a single cell body model circuit and an amplifier circuit. The developed P-HNM circuit is an oscillation circuit characterized by a firing threshold and a refractory period, and produces a continuous pulse similar to the pulses delivered to biological neurons. And it shows the single voltage pulse. The controlled robot is insect-type microrobot that is fabricated by the micro electro mechanical systems (MEMS) process. The MEMS microrobot is constructed by leg parts and an impact-type rotary actuator that uses a multilayer ceramic piezoelectric element. The rotational motion is generated by the single voltage pulse. The dimensions of the driving circuit that is including the bare chip IC are 2.9 mm and 4.7 mm, length and width, respectively. The fabricated driving circuit can realize the mountable size to the millimeter scale robot.

IC design of pulse-type hardware neuron model for piezoelectric element impact-type MEMS microrobot

This paper presents the integrated circuit (IC) which could output a driving waveform to generate the walking motion of the piezoelectric element impact-type micro electro mechanical systems (MEMS) microrobot. The microrobot was made from silicon wafer fabricated by micro fabrication technology. The size of the fabricated robot was 4.0 × 4.6 × 3.6 mm. IC design of the pulse-type hardware neuron model (P-HNM) had been done by using CMOS process. P-HNM has the same basic features of biological neurons to generate the pulse waveform. Therefore, P-HNM outputs the driving waveform using electrical oscillation such as biological neuron. In this paper, we showed that the P-HNM which outputs the driving waveform for the piezoelectric element impact-type MEMS actuator could design as bare chip IC. As a result, we showed that P-HNM with driving circuit could generate the driving waveform of the rotary-type actuator of piezoelectric element impact-type MEMS microrobot. The generation of the driving waveform could realize without any software programs or analog digital converters.

Impact-type MEMS microrobot controlled by bare chip IC of hardware neuron

This paper reports the hexapod-type millimeter size microrobot, which is composed of a link mechanism and an impact drive mechanism actuator based on a piezoelectric device. Developed mechanism is composed of the multilayer piezoelectric element and the micro components fabricated by micro electro mechanical systems (MEMS) technology. The microrobot was able to walk like insects. Walking motion was realized by rotation of the actuator and link mechanisms. The rotational motion was generated by the impact head attached to the piezoelectric element. Walking pattern emulates an insect and the microrobot can walk on uneven surfaces. The size of mechanical system of microrobot was 4.0mm, 4.6mm and 3.6mm, width, length, and height in size, respectively. The rotational speed of the actuator was 60 rpm at square wave of 20V and frequency of 25 kHz. The battery was externally connected. In this study, the control system using an hardware neuron is made from analog electronic circuits that mimic the behavior of the biological neuron. This neuron could generate the driving waveforms of the actuator without using any software programs. In this research, we develop the hardware neuron by analog CMOS IC bare chip. This bare chip was wire bonded to the pad pattern of the peripheral circuit. The size of the circuit board with IC was 5.5mm, 6.0mm the width and the length in the size, respectively. The weight of the electrical system was 0.082g whereas that of the mechanical system was 0.047g. The control system could output the driving waveform to operate the walking motion.