Seiji Hashimoto

Prof. Dr. Seiji Hashimoto

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 January 2024 in Sensors
Verified
Journal Article
Open access
PDF file
YCYu Cao
Yu Cao
KNKan Ni
Kan Ni
TKTakahiro Kawaguchi
Takahiro Kawaguchi
SHSeiji Hashimoto
Seiji Hashimoto
Autonomous mobile robots have become integral to daily life, providing crucial services across diverse domains. This paper focuses on path following, a fundamental technology and critical element in achieving autonomous mobility. Existing methods predominantly address tracking through steering control, neglecting velocity control or relying on path-specific reference velocities, thereby constraining their generality. In this paper, we propose a novel approach that integrates the conventional pure pursuit algorithm with deep reinforcement learning for a nonholonomic mobile robot. Our methodology employs pure pursuit for steering control and utilizes the soft actor-critic algorithm to train a velocity control strategy within randomly generated path environments. Through simulation and experimental validation, our approach exhibits notable advancements in path convergence and adaptive velocity adjustments to accommodate paths with varying curvatures. Furthermore, this method holds the potential for broader applicability to vehicles adhering to nonholonomic constraints beyond the specific model examined in this paper. In summary, our study contributes to the progression of autonomous mobility by harmonizing conventional algorithms with cutting-edge deep reinforcement learning techniques, enhancing the robustness of path following.

26 January 2025 in Sensors
Verified
Journal Article
Open access
PDF file
XJXiongwen Jiang
Xiongwen Jiang
TKTaiga Kuroiwa
Taiga Kuroiwa
YCYu Cao
Yu Cao
LSLinfeng Sun
Linfeng Sun
HZHaohao Zhang
Haohao Zhang
SHSeiji Hashimoto
Seiji Hashimoto
With the rapid development of automation and intelligent technology, mobile robots have shown wide application potential in many fields, and accurate navigation systems are the key to robots completing tasks. This paper proposes an enhanced pure pursuit path tracking algorithm for mobile robots, which is optimized using NSGA-II, with high-precision GNSS navigation for accurate positioning. The improved algorithm considers the dynamic characteristics and real–world operating conditions of the robot, optimizing steering decisions to enhance path tracking accuracy. Experimental results demonstrate the effectiveness of the algorithm: with a look–ahead distance of 0.5 and a maximum linear velocity of 3, the average absolute pose error (APE) is reduced by 14.63%, while a velocity of 4 reduces the APE by 55.94%. The enhanced algorithm significantly reduces path deviation and improves navigation performance.

3 January 2024 in IEEE Journal of Emerging and Selected Topics in Power Electronics
Verified
Journal Article
Closed access
LSLinfeng Sun
Linfeng Sun
WJWei Jiang
Wei Jiang
SHSeiji Hashimoto
Seiji Hashimoto
Zhengyu LinZhengyu Lin
Zhengyu Lin
TKTakahiro Kawaguchi
Takahiro Kawaguchi
The DC micro-grid has emerged as an increasingly popular solution for localized energy integration and dispatching. With multiple DC micro-grids in a system, an effective DC tie can facilitate various generation, storage, and consumption modes. It enhances energy versatility and contributes to improved energy resiliency. Hence, this paper introduces the concept of a multi-port energy router (MER) aims to multiplex DC power across various DC communities all with close-margin bus voltages. The proposed MER functions as a "super node" following Kirchhoff’s current law. It incorporates a unique partial power topology, enabling direct control of DC current flow between any two buses or towards local energy storage, solely based on bus voltage differences. To align modulation and control with industrial standard frameworks and provide flexibility in controlling energy storage current, a multi-dimension space vector modulation method is proposed. The instantaneous power theory is re-defined for the DC energy router’s operation. The power transfer efficiency of the standard half-bridges partial power topology is empirically verified through rigorous testing. Various operational scenarios are examined to demonstrate the feasibility of the MER concept, with findings supported by both simulation and experimental data.

1 January 2020 in Processes
Verified
Journal Article
Open access
PDF file
SXSong Xu
Song Xu
SHSeiji Hashimoto
Seiji Hashimoto
YJYuQi Jiang
YuQi Jiang
KIKatsutoshi Izaki
Katsutoshi Izaki
TKTakeshi Kihara
Takeshi Kihara
WJWei Jiang
Wei Jiang
Artificial neural networks (ANNs), which have excellent self-learning performance, have been applied to various applications, such as target detection and industrial control. In this paper, a reference-model-based ANN controller with integral-proportional-derivative (I-PD) compensation has been proposed for temperature control systems. To improve the ANN self-learning efficiency, a reference model is introduced for providing the teaching signal for the ANN. System simulations were carried out in the MATLAB/SIMULINK environment and experiments were carried out on a digital-signal-processor (DSP)-based experimental platform. The simulation and experimental results were compared with those for a conventional I-PD control system. The effectiveness of the proposed method was verified.

5 June 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
YCYu Cao
Yu Cao
KNKan Ni
Kan Ni
XJXiongwen Jiang
Xiongwen Jiang
TKTaiga Kuroiwa
Taiga Kuroiwa
HZHaohao Zhang
Haohao Zhang
WJWei Jiang
Wei Jiang
The potential of autonomous driving technology to revolutionize the transportation industry has attracted significant attention. Path following, a fundamental task in autonomous driving, involves accurately and safely guiding a vehicle along a specified path. Conventional path-following methods often rely on rule-based or parameter-tuning aspects, which may not be adaptable to complex and dynamic scenarios. Reinforcement learning (RL) has emerged as a promising approach that can learn effective control policies from experience without prior knowledge of system dynamics. This paper investigates the effectiveness of the Deep Deterministic Policy Gradient (DDPG) algorithm for steering control in ground vehicle path following. The algorithm quickly converges and the trained agent achieves stable and fast path following, outperforming three baseline methods. Additionally, the agent achieves smooth control without excessive actions. These results validate the proposed approach’s effectiveness, which could contribute to the development of autonomous driving technology.

28 March 2021 in Electronics
Verified
Journal Article
Open access
PDF file
WJWei Jiang
Wei Jiang
LSLinfeng Sun
Linfeng Sun
YCYan Chen
Yan Chen
HMHaining Ma
Haining Ma
SHSeiji Hashimoto
Seiji Hashimoto
This paper proposes a low-cost on-chip Hardware-in-the-Loop (HIL) platform for teaching and fast prototyping of dynamic systems. A dual-core digital signal controller (DSC)-based solution is proposed for the HIL system. CPU core A, as the simulation engine, is dedicated to circuit and system simulation. The actuation and control logic are implemented in CPU core B, which is working as the control engine. Inter-processor communication is used to interchange variables between the CPUs. The digital-to-analog converter and digital outputs are used to send the duty cycle and system state variables to the oscilloscope for users’ visual feedback. Two typical systems with fast and slow dynamics are modeled and implemented in the simulation engine. Under the excitation generated by the control engine, system dynamics can be observed for studying purposes. Close-loop control for a buck converter is also demonstrated on the developed prototype, where both input voltage and load variations performance are tested. The test results indicate that the digital simulator can well emulate the average small signal model of a power converter in open-loop and close-loop scenario. Meanwhile, the control parameters can be modified for system performance evaluation and education purposes. The proposed low-cost HIL system can be easily applied to the engineering teaching as well as fast prototype development phase of product design.