Norihiro Kamamichi

A snake-like swimming robot using IPMC actuator/sensor

We constructed a snake-like swimming robot using IPMC actuator, and verified swimming motion based on numerical simulation and experiments. In applying periodic inputs with appropriate frequency and phase shift, the snake-like robot is capable of smooth propulsion. It is known that IPMC has a sensor function that IPMC films generate electromotive voltage when bending or being deformed. By using the sensor function into the snake-like robot, it is considered that autonomous propulsive motion can be realized by feedback of the sensor signal. In this paper, we consider the autonomous locomotion of the snakelike swimming robot with IPMC actuator/sensor, and verify the realization of swimming motion by feedback of the sensor signal. Furthermore, the efficiency of the autonomous locomotion is investigated

A novel gait generation for biped walking robots based on mechanical energy constraint

This paper proposes novel energy-based gait generation and control methods for biped robots based on an analysis of passive dynamic walking. First, we discuss the essence of dynamic walking using a passive walker on a gentle slope from the mechanical energy point of view. Second, we propose a simple and effective gait-generation method, which imitates the energy behavior in every walking cycle considering the zero-moment point condition and other factors of the active walker. The control strategy is formed by taking into account the features of mechanical energy dissipation and restoration. Following the proposed method, the robot can exhibit a natural and reasonable walk on a level ground without any gait planning and design in advance. The effectiveness of the method is examined through numerical simulations and experiments.This paper proposes a novel energy-based control law for biped robots based on an analysis of passive dynamic walking. Firstly we discuss the essence of dynamic walking using a passive walker on a gentle slope. In the second, we propose a simple and effective control law which imitates the energy behavior in every cycle considering the ZMP condition and other factors of the active walker. The control strategy is formed by the feature of mechanical energy dissipation and restoration. By the effect of the proposed method, the robot can exhibit natural and reasonable walk on a level ground without any gait design in advance. The validity of the proposed method is examined by numerical simulations and experiments.

Integrated design of IPMC actuator/sensor

We are studying about robotic application of ionic polymer-metal composite (IPMC). The characteristics of IPMC highly depend on the type of counter-ions, and it is considered that the performance of the actuators can be improved by combining the actuators with several types of counter-ions and applying an integrated control. IPMC has also a sensor function, as the IPMC film generates electromotive force when it is deformed. It has possibility to be integrated into IPMC actuator with soft actuation. In this paper, we consider an integrated design of IPMC actuator/sensor, and investigate a control of the combined IPMC actuators using Hinfin control and the construction of IPMC sensor system

A snake-like swimming robot using IPMC actuator and verification of doping effect

Ionic polymer metal composite (IPMC) is one of the most promising EAF actuators for applications, and slave good property of response and durability. The characteristics of IPMC materials depend on a type of counter ion. In applying to mechanical systems such as a robot, there exist possibilities to change the properties of the dynamics by changing the counter ions according to environment or purpose adequately. In this paper, we consider swimming of a snake-like robot with IPMC actuator, and demonstrate a smooth swimming motion. Then, we also verify the doping effects by experiments.

Extended virtual passive dynamic walking and virtual passivity-mimicking control laws

In our previous works (2000), we have proposed virtual passive dynamic walking utilizing modified gravity condition with virtual gravity field. The virtual passive walking motion critically depends on the physical parameters and the steady walking pattern is not easily obtained without suitable physical parameters. In this paper we propose a more generalized method of virtual passive walk and a virtual passivity mimicking control law. With the effect of the control laws, we can generate the steady walking pattern even if the physical parameters are not suitable. We call the walking pattern generated by the control methods as extended virtual passive dynamic walking. The validity of the proposed method is examined by numerical simulations and tested by a prototype experimental machine.

IPMC Linear Actuator with Re-Doping Capability and its Application to Biped Walking Robot

Abstract We are developing an artificial muscle linear actuator using ionic polymer-metal composite (IPMC) which is an electro-active polymer (EAP) that bends in response to electric stimuli and the goal of our study is applying the actuator to robotic applications especially to a biped walking robot. In this paper, we will describe the structure of the actuator and an empirical model of the actuator, and whose parameters are identified from input-output data. Based on the empirical model, basic experiments and position control of the linear actuator are demonstrated. We consider walking control of a small-sized biped walking robot and investigate changes of the characteristics of the actuator for walking by ionic re-doping chemically. In the application we assume that the developed actuators are connected both in series and in parallel to a joint of the walking robot so that the actuators supply enough torque to the robot and that they are stretched and compressed enough. It is shown throughout simulations that the biped walking robot with the actuators can walk on a level ground with a period synchronized with a period of input signal, and that walking patterns are changed by ionic re-doping.