Extraction of combined environmental information by bilateral control based on DFT modal control

Future robots are expected to support human physically. The physical support by them should be based on the individual's sensation and action. This means the robots must actively recognize the unknown environment according to the individual's action. They also have to transmit the obtained environmental information to the individual in harmony with his or her sensation. Then, real world haptics will be a key technology for the realization of human support. There are two kinds of environmental information. One is the spatial information of environmental modes. The other is the temporal information of environmental impedance. Both spatial information and temporal information are so important for recognition of the unknown environment. Then, this paper proposes the extraction method of the combined environmental information based on real world haptic techniques. In the proposed method, the combined environmental information is extracted by bilateral motion control based on discrete Fourier transform (DFT) modal control. As a result, the environmental modes and the environmental impedance are able to be extracted simultaneously. In addition, the environmental impedance is able to be associated with each environmental mode based on DFT. Finally, the validity of the proposed method is verified by the experimental results.