Bilateral Teleoperation With Autoelimination of Probing Signal for Environmental Impedance Identification Considering Operability

Abstract

Environmental impedance recognition is important for abstracting human dexterous motion characteristics. One of the methods to abstract such beneficial information is bilateral teleoperation, which expresses the interaction between the human and the object. To identify the environmental impedance, injecting a probing signal with a wide range of frequency components is an effective method for improving system identification performance. However, such signals introduce vibration components that deteriorate human operability; therefore, there is a tradeoff between identification performance and operability. Hence, a probing signal autoelimination method based on the environmental impedance identification error is proposed. When the identification error is adequately small, the probing signal should be eliminated to avoid disturbance. Conversely, when the identification error increases because of environmental variation, the probing signal is reinjected. The proposed method can adaptively switch between injection and elimination of the probing signal according to changes in the environment. Furthermore, the effect of the probing signal is analytically formulated, and its characteristics are clarified. Therefore, the proposed approach overcomes the tradeoff between identification performance and operability. The effectiveness of the proposed method is experimentally validated by evaluating the convergence of identified impedance parameters and the squared identification residual under spring-type environments.