〈Vol.10 No.3(2017.5)〉



[Special Iuue on SICE Annual Conference 2016]

[Contributed Papers]


■ Approximate MLD System Model of Switched Linear Systems for Model Predictive Control

Hokkaido University・Shin KANAZAWA, Koichi KOBAYASHI, and Yuh YAMASHITA

In this paper, to reduce the computation time for solving the finite-time optimal control problem (i.e., the model predictive control  (MPC) problem), an approximate model of switched linear systems is proposed. A switched linear system is one of the typical subclasses of hybrid systems, and has several applications such as networked control systems. First, an approximation of the state variable in switched linear systems is derived. Next, using auxiliary binary and continuous variables, an approximate model given by a mixed logical dynamical system model is derived. Using this approximate model, the dimension of  the auxiliary continuous variable can be reduced. As a result, the online computation time in MPC can decrease. Finally, the effectiveness  of the proposed method is presented by a numerical example.


■ Some Improvements in Elastoplastic Friction Compensator

Kyushu University・Masayoshi IWATANI and Ryo KIKUUWE

For robotic joints with compliant transmissions, Mahvash and Okamura have proposed a friction compensator based on an elastoplastic friction model. One drawback of the compensator is that the compensator continues producing non-zero output force in the static friction state, which results in the degraded backdrivability of joints. In order to remedy this problem, this paper proposes an elastoplastic friction compensator with improved static friction behavior, which is realized by an additional term that makes the output force exponentially decay in the static friction state. This paper also proposes an additional algorithm that adjust the decay rate of the output force in real time. The proposed methods are experimentally tested with a linear actuator with a timing belt and a six-axis industrial manipulator.


■ The Detection of the Rise to Stand Movements Using Bereitschaftspotential from Scalp Electroencephalography (EEG)

Kyushu Institute of Technology・Balbir SINGH,
Kyushu Institute of Technology/Riken BSI・Hiroaki WAGATSUMA,
and Kyushu Institute of Technology・Kiyohisa NATSUME

The negative-going Bereitschaftspotential (BP) is associated with the preparation and execution of dynamic movement. So far, BP for simple movements involving either the upper or the lower body has been studied. However,BP has not yet been recorded during both movements. Our study reveals that the negative-going BP was evoked around 3 to 2 seconds before the onset of the rise in response to start cue. The BP had a negative peak before the onset of the movement of the trunk. BP for the rise to standing up was started around -3 seconds. The corresponding BP could not be recorded during keep seated in response to the other start cue. Then we tried to discriminate the onset for rise to stand,and for keeping seated using BP data in time domain. BP for 0.5 seconds in the time window is used for the time-shifted leave-one-out cross validation method. The method shows that using 0.5 – 2 seconds before the onset of the movement could detect whether the subject would stand up or keep seated with the correction rate of about 60-70%. These results suggest that using the negative BP can detect the subject’s will to stand-up.


■ Effects of Cruising Speed on Steering Oscillations of Car Induced by Modeled Cognitively Impaired Human Driver

Doshisha University・Dipak G. SHARMA, Rahadian YUSUF,
Ivan TANEV, and Katsunori SHIMOHARA

In this paper, we proposed an approach that uses genetic programming (GP) to automatically develop a driving agent ? as a model of a human driver ? to optimally steer a realistically simulated car with an instant, non-latent steering response. Using the latter, we tested the hypothesis that introducing a delay in the steering response of an evolved model of a human driver results in well-expressed steering oscillations. We further evaluated the effects of speeding on the steering oscillation and observed that (i) the evolved model of the human driver (driving agent) could robustly control the car driven at various speeds and (ii) the increase in speed results in increase of amplitude of observed steering oscillations. The detection of these oscillations could pave the way for providing early warnings of inadequate driver cognitive load (as an underlying cause of such delays) in normal driving conditions ? well before any urgent response to an eventual hazardous traffic situation may be required.


■ Area-Efficient Decimation Filter with 50/60 Hz Power-Line Noise Suppression for ΔΣ A/D Converters

Azbil Corporation・Hideki KURIBAYASHI, Tetsuya KAJITA

This paper introduces a new digital filter utilizing a SINC filter used in ΔΣ A/D converters and featuring 50/60 Hz power-line noise rejection. Compared
to a simple series connection of the SINC filter and a noise suppression filter for the power-line,this digital filter reduces gate size by approximately 40% and enables the attenuation of 50 Hz and 60 Hz elements by approximately 55 dB.


■ Evaluation of Grasping Accuracy When Using a Passive Force Display Glove

Toyama Prefectural University・Ken'ichi KOYANAGI,

In virtual reality (VR) technology, force feedback/display devices are expected to enhance fine sensation and contribute to the user's immersive experience. This is particularly true for glove-type devices. Force display gloves, however, do not have a specific numerical value to indicate display accuracy. In this paper, we report the results of sensory testing and analysis with VR cylindrical objects using a passive-type force display glove. The size discrimination threshold for grasping was determined to be smaller than the nominal average error of the device; however, the threshold was larger than either the actual accuracy of the device or the threshold from an organoleptic test of a barehanded human. We have also identified the possible superimposition of the sensory accuracy errors of the operator with those of the glove. Despite this finding, we have determined that the device shows adequate accuracy for representing cylindrical objects during specific grasping tasks.


■ Vibrotactile Stimulation to Change Velocity Perception in Automobiles

Nagoya Institute of Technology・Motoki TACHIIEI,
Yoshihiro TANAKA and Akihito SANO

Velocity perception is important in safety, traffic jam relaxation, concentration and drivability enhancement while driving automobiles. This paper proposes control of velocity perception by using vibrotactile stimulation. We have focused on vibrotactile stimulation since tactile stimulation can be reasonable and be privately given to a driver. First, the seat vibration is measured using actual vehicle to discover available stimulation of changing velocity perception. The results shows that peak frequency clearly increases with the rise of velocity and the intensity roughly increases. Then we investigate the influence of intensity or frequency- shifted vibrotactile stimulation on the velocity perception by using a driving simulator reflecting actual vehicle characteristics. Experimental result shows a possibility of changing velocity perception by using frequency-shifted vibrotactile stimulation.


■ An Improvement Method for Program Structure Using Code Clone Detection, Impact Analysis, and Refactoring Formats

University of Yamanashi・Masakazu TAKAHASHI, Dai-ichi Institute of Technology・Reiji NANBA,
University of Yamanashi・Yunarso ANANG, and Yoshimichi WATANABE

This paper proposes a method that aggregates similar portions (code clones) in the developed program and redesigns the current program structure to an adequate program structure. The procedure of the proposed method is followings: Code clones are detected, and their characteristics are extracted, the design methods that code clones are aggregated are proposed, the program is modified, and the affected portions in the program are clarified and retested. Furthermore, a tool that supports the proposed method is created.  As a result of applying the proposed method and the tool, it is found that 45% CCs are aggregated and 13% instructions of the program are deleted. Additionally, it is found that an adequate program structure is realized by using the proposed method and the tool.


■ Constrained Optimal Flyby Guidance Algorithm by Iterative Two-Stage Stochastic Programming

The University of Tokyo・Naoya OZAKI, Yosuke KAWABATA,
The University of Tokyo・Ryu FUNASE, and JAXA・Yasuhiro KAWAKATSU

Interplanetary micro-spacecraft have been recently demonstrated for various missions. Orbital control of micro-spacecraft is challenging because the spacecraft systems have severe constraints. This paper presents a constrained optimal flyby guidance algorithm. We iteratively introduce two-stage stochastic programming and achieve rapid and global optimization by using delta-v mappings and cross-correlation technique, which is well-known in the field of image and signal processing. Finally, numerical examples and Monte-Carlo simulation show that the proposed algorithm is efficient in terms of the expected total delta-v.


■ Delay-Independent Synchronization and Network Topology of Systems with Transmission Delay Couplings

Tokyo Metropolitan University・Koki RYONO and Toshiki OGUCHI

We investigate the relationship between graph topology and delay-independent synchronization occurs in networks of the identical nonlinear systems with transmission delays. In this paper, we show that if networks contain a cycle subgraph of an odd number of nodes, partial synchronization corresponding to the equitable graph partition with the fewest cells occurs for a sufficiently large coupling strength regardless of the size of time-delay.The validity of the obtained results are examined through numerical simulations of Hindmarsh-Rose neuron systems networks.


■ Visual Feedback Position Tracking and Attitude Analysis of Two-Wheeled Vehicles Integrating a Target Vehicle Motion Model

Tokyo Institute of Technology・Satoshi NANANO,Tatsuya IBUKI,Mitsuji SAMPEI

This paper studies visual feedback position tracking control of two-wheeled vehicles in the situation that a camera and a target object are attached to the vehicles, respectively.Here, the body velocity of the target object vehicle is modeled as a Fourier series expansion.The relative position between the camera and the target object is controlled to the desired relative position.The present control law is based only on visual measurements, and the necessary information to implement the law is estimated by them.The asymptotic stability of the equilibrium of the total system including the internal attitude behavior is analyzed under some conditions of the target object vehicle velocity via stability theory of perturbed systems.Finally, a numerical simulation is conducted to show the effectiveness of the proposed method.


■ An Intra-Oral Interface to Affect a Taste Change Continuously by Using Electrical Stimulation with Periodic Intervals

University of Tsukuba・Kazuki TSUKAMOTO and Tomoyuki YAMAGUCHI

Recently, increasing attention has been paid to the health impacts and lifestyle diseases due to the excessive intake of salt and sugar. To address this problem, there have been studies to control taste by the electrical stimulation of food and drink through tableware. However, it is not possible to realize a change of taste during the chewing of food and drink with this approach. Therefore, we consider that a change of taste is also required during chewing in order to achieve satisfied consumption. In this study, we develop an intra-oral interface to effect a taste change continuously by using electrical stimulation. We performed preliminary experiments to measure the sensitivity of the tongue by the position and area of an electrode. Then, we developed an interface to take into account the results of the experiments. We confirmed the effectiveness of the proposed interface through experiments examining the intensity of taste when using the developed interface. Moreover, by having periodic intervals to electrical stimulation by the PWM control the proposed interface was confirmed that can improve the intensity of taste continuously.


■ Effect of Instructions on Parts' Positions during an Assembly Task on Efficiency and Workload

Gifu University・Kojiro MATSUSHITA, Keita NIWA,
Satoshi ITO, and Minoru SASAKI

This paper examines the effect of instructions on parts' positions during an assembly task having numerous parts for someone to remember where they are located. Hypothesizing that instructions relating to the positions of the parts would enhance work efficiency and reduce workload, we designed an experimental method to test this theory. In this experiment using educational blocks, visual instructions were given by illuminating the space where the parts are kept, while auditory instructions were provided to aid locating the parts to compare the efficiency of visual and auditory instructions.Experiments with six participants showed that the visual instruction significantly shortened not only the search time but also the assembly time (which was one way in which efficiency was assessed in this study). The use of parts' positions instructions tended to reduce the workload as evaluated with NASA-TLX compared with the cases without instructions.


■ The Relative Speed Control of Super Multi-Link Space Manipulator to Capture Space Debris

Yokohama Nationaol University・Shunsuke KURODA,
Takehiro HIGUCHI, Yoshito TSUJIMOTO, Seiya UENO

Space debris became one of the difficulties for mankind to utilize the space environment. Among the variable efforts to the debris problem, the development of technology for the active debris removal (ADR) is especially imperative. This paper is on the motion simulation of debris capture manipulator for ADR with large number of links. Lightweight actuator using hydrogen storage alloy is developed for use in outer space as an actuator for the manipulator. The controllable time with the extended resolved motion rate control was examined in the past study. In this paper, to research the motion of the debris in the interaction with the end-effector, the simple collision model for the special end-effector was established. The control law to lower the relative velocity after the impact is brought in, and the results has shown almost 90\% of reduction regardless of the initial velocity of moving target debris. The proposed system will enable the system to capture the target debris more safely.


■ Gain-Scheduled Control/Steering Design for a Spacecraft with Variable-Speed Control Moment Gyros

Osaka Prefecture University/University of Colorado Boulder・Takahiro SASAKI
and Osaka Prefecture University・Takashi SHIMOMURA

In this paper, we establish the dynamics of a spacecraft with Variable-Speed Control Moment Gyros (VSCMGs). Based on this dynamics, we develop an easy-to-use Linear Parameter-Varying (LPV) model, in which we deal with 3-axis attitude control of a spacecraft with pyramid-array VSCMGs. Although it is hard to consider overall stability and control performance of attitude control at the same time with conventional Lyapunov function-based controllers, this paper attains both of them via LPV control theory. And also we design two types of Gain-Scheduled (GS) steering laws for singularity avoidance and escape. Through numerical examples, the efficiency of the proposed GS controller and the GS steering laws is demonstrated.


L1 Adaptive Control for Single-Input Multiple-Output (SIMO) Non-Homogeneous System with MR Damper Semi-Active Suspension

Keio University・Yongyut UPPATTHANGKUL and Hiromitsu OHMORI

During the investigation of controlling the magnetorheological(MR) damper semi-active suspension controlling system with L_{1} adaptive controller, the method is introduced by taking an account of avoiding the solving process of the convolution of transfer matrix in non-homogeneous system, and the performance of the system must have an acceptable result. The result, which is simulated by MATLAB/SIMULINK, proves that the proposed control architecture can work well for reducing calculation process. Moreover, this method is compared with auto-tuned PID function in SIMULINK; as a result, the method shows a better overall performance by adjusting a few parameters.


■ MPC-Based Surveillance over Graphs by Multiple Agents

Hokkaido University・Mifuyu KIDO, Koichi KOBAYASHI, and Yuh YAMASHITA

The multi-agent surveillance problem over graphs is to find trajectories  of multiple agents that travel each node as evenly as possible. This  problem has several applications such as city safety management and  disaster rescue. In this paper, the finite-time optimal surveillance  problem is formulated, and is reduced to a mixed integer linear  programming (MILP) problem. Based on the policy of model predictive  control, an optimal trajectory is generated by solving the MILP problem  at each discrete time, and persistent surveillance can be realized.  Finally, a numerical example is presented, and further discussion is  also provided.


■ State Estimation under Lebesgue Sampling and an Approach to Event-Triggered Control

Keio University・Takahiro KAWAGUCHI, Masaki INOUE, and Shuichi ADACHI

In a standard setup of conventional state estimation problems, the output signal of a dynamical system is sampled at every regular time interval. This paper addresses an estimation problem under event-triggered sampling: an irregular sampling rule in which the output signal is sampled only when a specified event occurs. In particular, this paper focuses on the Lebesgue sampling, which is a type of event-triggered sampling such that the output signal is sampled only when it crosses specific thresholds. In the proposed estimation method, not only information in the sampled points but also that in the inter-sample intervals are utilized to improve the estimation accuracy efficiently. The particle filter is applied to the estimation since the inter-sample information makes the distribution of the estimates non-Gaussian.Furthermore, the proposed estimator is combined with a linear-quadratic-regulator (LQR) type state-feedback controller.The derived control law can be an effective approach to an event-triggered control problem in which the Lebesgue- sampled output is utilized. The effectiveness of both of estimation and control methods is examined through numerical examples.


■ Opinion Formation over Signed Gossip Networks

Osaka University・Linh Thi Hoai NGUYEN, Takayuki WADA,
Kobe University・Izumi MASUBUCHI,
Nagoya Universitiy・Toru ASAI, and Osaka University・Yasumasa FUJISAKI

Opinion formation is investigated over signed gossip networks, where  asymptotic and transient opinion behaviors are analyzed in detail. The network is modeled by a connected signed graph, where each edge  of the graph has positive or negative weight, i.e., these edges represent friendly or hostile relationship. Interactions each of which occurs between two persons chosen randomly follow an  asynchronous procedure. Then it is shown that their opinions always  converge in mean square and converge almost surely. A convergence  time is defined as the smallest time such that it takes for the values of nodes to get within a given neighborhood of the consensus value with high probability, regardless of initial state. An upper  bound and a lower bound of the convergence time of the gossip algorithm are given in terms of a structure of the given network.