Leaky Coaxial (LCX) cable is a line-shaped cable with huge number of slots used to transmit / receive wireless signal. Due to its changeable shape and stable and uniform radiation characteristics along cable, it has been largely used for wireless coverage over many scenarios such as linear-cell environments and any irregular shape of coverage. In addition, by opening and closing (On/Off) partial slots, LCX cable can largely increase the total number of different channel patterns, which benefits the capacity increase for LCX system using spatial modulation (SM). However, due to the large number of slots, it is difficult to find an optimal solution in terms of channel patterns set generated from On/Off status of LCX slots, which can be treated as an NP-complete combination optimization problem. In this paper, we propose an efficient channel pattern selection based on genetic algorithm (GA) for 2-by-2 LCX-MIMO system using single LCX.

This paper proposes a load-side acceleration control scheme for geared motors affected by unknown backlash and friction. A backlash-deactivated disturbance observer (BDDOb) is proposed to achieve load-side acceleration control while ensuring quick traversing of backlash. The BDDOb works by executing conditional estimation-compensation of load disturbances, and is driven by a backlash detection scheme based on torsion torque sensing which does not require any information on the backlash gap width. In addition, a variable-order force-position-integrated disturbance observer (VOFPIDO) is proposed to quickly compensate nonlinear friction without requiring information of the nonlinear friction magnitude by applying velocity-dependent switching. Experimental results prove the effectiveness of the proposed method.

This paper focuses on single inertialization on the load-side parameter of two-inertia system and employs the equivalent disturbance compensator (EDC). Conventional EDC is designed in case of the plant system without friction; thus, the back-forward drivability control using the EDC is affected by friction. In this paper, we propose the back-forward drivability control using EDC and DOB for single inertialization of two-inertia system. DOB is used to compensate the friction and the EDC is applied to not only improve the back-forward drivability, but also suppress the vibration on load-side output. This proposal consists of basic actuator and force sensor and it is available to general robot actuator that uses current sensor, motor encoder, and force sensor. The effectiveness of proposed back-forward drivability control is verified through the numerical simulation.

This paper addresses fully-online always-adaptation of a transfer function for robot audition systems based on microphone array processing. The transfer function represents signal propagation characteristics between a microphone and a sound source, which provides essential information for real-world scene analysis, such as sound source localization and separation for robots. Although it is commonly defined as a stationary function, it should be considered together with room acoustics and their environmental changes for practical use, that is, it should be defined as a dynamically-changing function. To fulfill this requirement, we propose a fully-online always-adaptation method for a transfer function, by continuously estimating the transfer function from the observed signals in a passive manner, while performing sound source localization and separation. The proposed method was implemented on open source robot audition software HARK as modules which works online. These modules are applied to sound source localization and separation which are primary functions in robot audition. Experimental results showed that the proposed method successfully adapted to an office environment and improved the performance of sound source localization and separation at a close level to the transfer function recorded in the room.

Load-side acceleration sensing based on load-side acceleration control is proposed for a two-inertia resonance system. The proposed method is divided into two stages. In the first stage, the feedback component from the load-side is canceled using the estimated value of the instantaneous state observer and the load-side acceleration. The two-inertia resonance system is converted into a simple second-order system using this method. The proposed method configures a control system of cascaded loops for the second-order system. Therefore, the load-side acceleration control is achieved by two specified bandwidths. The proposed method is easy to implement for conventional robots and yields superior cost-savings compared with other types of load-side acceleration control. The effectiveness of the proposed load-side acceleration controller is verified by theoretical analysis, numerical simulations, and experiments.

For the high performance of force/torque control, an approach using a disturbance observer is known to be effective. However, a conventional disturbance observer cannot perfectly compensate for the disturbance torque when the disturbance torque (for example, impact torque) is instantaneous. This paper proposes a force and position sensors integrated disturbance observer (FPIDO), and analyzes its disturbance-suppression performance. Moreover, this paper focuses on high-performance torque control using a torsion torque sensor for a two-inertia system. The disturbance-suppression performance of the conventional disturbance observer and the FPIDO are compared using experimental results for motor-side acceleration control and load-side torque control. Finally, the experimental results verify the effectiveness of the proposed disturbance observer.

Recently, a soft robot considering the contact of the human has attracted attention, and the zero stiffness torque control is required. Because a soft robot causes vibration at the load side, vibration suppression control of a soft robot is required. In this paper, the authors discuss position control and torque control of a soft robot by using a torsion torque sensor based on a resonance ratio control. Position control can be used to design parameters. However, torque control cannot be used to design parameters because the proportional gain Kp and resonance ratio gain Kr are not independent with regard to integral-proportional differential(I-PD) torque control. Therefore, in the case of torque control, resonance ratio control is equivalent to I-PD control.

The fusion of graphene with silicon may provide an effective solution to the problem of scale in electronic devices. This approach will allow the excellent electronic properties of graphene to be combined with known Si device technologies. We review the epitaxial growth of graphene on Si substrates (GOS) for fabricating transistors. GOS has been multifunctionalized by controlling the orientation of the Si substrate. The site-selective epitaxy of GOS has also been developed by controlling the base SiC thin films. These results demonstrate that GOS is suitable for integrated devices.