Research Achievements - Original paper -
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Shunsuke Nansai, Norihiro Kamamichi, Akihiro Naganawa
Automation ( Multidisciplinary Digital Publishing Institute (MDPI) ) 6 ( 4 ) 2025.11 [Refereed]
Research paper (journal) Domestic Co-author
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Design and evaluation of Lizard-Inspired Single-Actuated robot
Shunsuke Nansai, Norihiro Kamamichi
ROBOMECH Journal ( Robomech Journal ) 12 ( 16 ) 2025.05 [Refereed]
Research paper (journal) Domestic Co-author
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Path Following Control of Lizard-Inspired Single-Actuated Robot utilizing Kinematics
Shunsuke Nansai, Norihiro Kamamichi
Journal of Advanced Simulation in Science and Engineering ( 一般社団法人 日本シミュレーション学会 ) 12 ( 1 ) 61 - 79 2025.04 [Refereed]
Research paper (journal) Domestic Co-author
<p>The purpose of this paper is to design a path following control system based on the kinematics of the Lizard-Inspired Single-Actuated robot (LISA). LISA is a new type of robot that mimics the quadrupedal walking morphology of lizards with a four-bar linkage mechanism and can realize both propulsion and turning with 1 degree-of-freedom. To achieve this purpose, this paper takes 3 approaches: kinematics formulation, control system design, and numerical simulation. In the kinematics formulation, we formulate LISA’s turning angle, stride length, posture, propulsive direction, curvature, and position coordinate. In control system design, we design a control system that converges not only distance error but also the posture error and control input. Conditional equations that can achieve these 3 control targets are formulated using forward kinematics and reference path functions, and control inputs are obtained by solving the inverse problem. Numerical simulations verify the effectiveness of the designed control system using 3 types of trajectories: linear, circular, and a combination of circular and linear trajectories. As a result, it is confirmed that the designed control system is effective for all 3 types of trajectories and that not only the distance error but also the attitude and control input can be converged.</p>
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The Area Measurement Method for Esophageal Lesion under Endoscopy
Narita Ryo, Nansai Shunsuke, Hoshizaki Midori, Manabe Noriaki, Haruma Ken, Oka Kiyoshi, Naganawa Akihiro
The Japanese Journal of the Institute of Industrial Applications Engineers ( The Institute of Industrial Applications Engineers ) 12 ( 1 ) 17 - 26 2024.03 [Refereed]
Research paper (journal) Domestic Co-author
The risk of developing esophageal cancer from Barrett's Esophagus (BE) is associated with its size. However, the study to measure BE area is not advanced well. In this paper, we propose the method to measure BE area from one endoscopic image with camera distance. First, we assume that the esophagus is a cylinder and the camera is a pinhole camera because 3D reconstruction of no-feature points object like an esophagus is difficult. And then, we get BE area indirectly by calculating the surface area of this virtual cylinder. In measurement experiments, we used USB camera and cylinder phantoms to evaluate the accuracy of the proposed method. The errors were about 4-6% in the bottom area, about 10% in the side area, and about 1±2.5 mm in the phantom's height measurement.
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Tracking Control of Lizard-inspired Single-actuated Robot Utilizing Posture Compensation -Control System Design and Experiments-
60 ( 3 ) 238 - 249 2024.03 [Refereed]
Research paper (journal) Domestic Co-author
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Sensitivity Analysis, Synthesis and Gait Classification of Reconfigurable Klann Legged Mechanism
A.A. Hayat, R.K. Megalingam, D.V. Kumar, G. Rudravaram, S. Nansai, M.R. Elara
Mathematics 2024.01 [Refereed]
Research paper (journal) International Co-author
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Window Shape Estimation for Glass Façade-Cleaning Robot
Takuma Nemoto，Shunsuke Nansai，Shohei Iizuka，Masami Iwase，Hiroshi Itoh
Machines 11 ( 2 ) 2023.02 [Refereed]
Research paper (journal) Domestic Co-author
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Modeling and Control of a Lizard-Inspired Single-Actuated Robot
Shouhei Noji, Shunsuke Nansai, Norihiro Kamamichi, Hiroshi Itoh
IEEE Robotics and Automation Letters 7 ( 3 ) 6399 - 6406 2022.05 [Refereed]
Research paper (journal) Domestic Co-author
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Locomotion Control of Snake-like Robot utilizing Friction Forces: Stability Verification of Model Following Servo Controller
Shunsuke Nansai, Hiroshi Itoh
Journal of Advanced Simulation in Science and Engineering ( Japan Society for Simulation Technology ) 9 ( 1 ) 113 - 127 2022.03 [Refereed]
Research paper (journal) Domestic Co-author
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Design and Implementation of a Lizard-Inspired Robot
Shunsuke Nansai, Yuki Ando, Hirodhi Itoh, Norihiro Kamamichi
Applied Sciences 11 ( 17 ) 2021.08 [Refereed]
Research paper (journal) Domestic Co-author
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Locomotion Control of Snake-Like Robot with Rotational Elastic Actuators Utilizing Observer
Shunsuke Nansai, Takumi Yamato, Masami Iwase, Hiroshi Itoh
Applied Sciences ( MDPI ) 9 ( 19 ) 1 - 26 2019.10 [Refereed]
Research paper (journal) Domestic Co-author
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Foot Location Algorithm considering Geometric Constraints of Facade Cleaning
Journal of Advanced Simulation in Science and Engineering ( Japan Society for Simulation Technology ) 6 ( 1 ) 177 - 188 2019.03 [Refereed]
Research paper (journal) Domestic Co-author
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Design and Experiment of a Novel Facade Cleaning Robot with a Biped Mechanism
Applied Sciences 8 ( 12 ) 1 - 17 2018.11 [Refereed]
Research paper (journal) International Co-author
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Floor cleaning robot with reconfigurable mechanism
Veerajagadheswar Prabakaran, Mohan Rajesh Elara, Thejus Pathmakumar, Shunsuke Nansai
Automation in Construction ( Elsevier ) 91 155 - 165 2018.03 [Refereed]
Research paper (journal) International Co-author
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A Novel Nested Reconfigurable Approach for a Glass Façade Cleaning Robot
Shunsuke Nansai, Mohan Rajesh Elara, Thein Than Tun, Prabakaran Veerajagadheswar, Thejus Pathmakumar
Inventions ( Multidisciplinary Digital Publishing Institute ) 2 ( 3 ) 2017.08 [Refereed]
Research paper (journal) International Co-author
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Speed Control of Jansen Linkage Mechanism for Exquisite Tasks
Shunsuke Nansai, Mohan Rajesh Elara, Masami Iwase
Journal of Advanced Simulation in Science and Engineering ( 一般社団法人 日本シミュレーション学会 ) 3 ( 1 ) 47 - 57 2016 [Refereed]
Research paper (journal) International Co-author
<p>This paper reports a toe speed control approach to achieving complex gaits with the Jansen linkage mechanism. In order to achieve complex gaits, delicate control of the toe is required. Since, the Jansen linkage mechanism is a closed loop linkage mechanism, the trajectory of the toe is defined uniquely by the set of link lengths. Hence, by controlling the toe speed, the locomotion of the toe can be controlled arbitrarily in response to intended purposes of its gait pattern. In this paper, we proved that the norm of the toe speed bears a proportionate relationship to the angular velocity of the driving link in a Jansen mechanism based robot platform. Using this relationship as basis, we derived the angular trajectory that results in a constant toe speed in the robot platform. Numerical simulations were performed to demonstrate the efficacy and validity of the proposed approach.</p>
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A novel approach to gait synchronization and transition for reconfigurable walking platforms
Shunsuke Nansai, Nicolas Rojas, Mohan Rajesh Elara, Ricardo Sosa, Masami Iwase
Digital Communications and Networks ( Chongqing University of Posts and Telecommunications ) 1 ( 2 ) 141 - 151 2015.04 [Refereed]
Research paper (journal) International Co-author
Legged robots based on one degree-of-freedom reconfigurable planar leg mechanisms, that are capable of generating multiple useful gaits, are highly desired due to the possibility of handling environments and tasks of high complexity while maintaining simple control schemes. An essential consideration in these reconfigurable legged robots is to attain stability in motion, at rest as well as while transforming from one configuration to another with the minimum number of legs as long as the full range of their walking patterns, resulting from the different gait cycles of their legs, is achieved. To this end, in this paper, we present a method for the generation of input joint trajectories to properly synchronize the movement of quadruped robots with reconfigurable legs. The approach is exemplified in a four-legged robot with reconfigurable Jansen legs capable of generating up to six useful different gait cycles. The proposed technique is validated through simulated results that show the platform׳s stability across its six feasible walking patterns and during gait transition phases, thus considerably extending the capabilities of the non-reconfigurable design.
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On a Jansen leg with multiple gait patterns for reconfigurable walking platforms
Shunsuke Nansai, Nicolas Rojas, Mohan Rajesh Elara, Ricardo Sosa, Masami Iwase
Advances in Mechanical Engineering ( Hindawi Publishing Corporation ) 7 ( 3 ) 1 - 18 2015.03 [Refereed]
Research paper (journal) International Co-author
Legged robots are able to move across irregular terrains and those based on 1-degree-of-freedom planar linkages can be energy efficient, but are often constrained by a limited range of gaits which can limit their locomotion capabilities considerably. This article reports the design of a novel reconfigurable Theo Jansen linkage that produces a wide variety of gait cycles, opening new possibilities for innovative applications. The suggested mechanism switches from a pin-jointed Grübler kinematic chain to a 5-degree-of-freedom mechanism with slider joints during the reconfiguration process. It is shown that such reconfigurable linkage significantly extend the capabilities of the original design, while maintaining its mechanical simplicity during normal operation, to not only produce different useful gait patterns but also to realize behaviors beyond locomotion. Experiments with an implemented prototype are presented, and their results validate the proposed approach.
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Dynamic modeling and nonlinear position control of a quadruped robot with theo jansen linkage mechanisms and a single actuator
Shunsuke Nansai, Rajesh Elara Mohan, Ning Tan, Nicolas Rojas, Masami Iwase
Journal of Robotics ( Hindawi Publishing Corporation ) 2015 ( 4 ) 2015.01 [Refereed]
Research paper (journal) International Co-author
The Theo Jansen mechanism is gaining widespread popularity among the legged robotics community due to its scalable design, energy efficiency, low payload-to-machine-load ratio, bioinspired locomotion, and deterministic foot trajectory. In this paper, we perform for the first time the dynamic modeling and analysis on a four-legged robot driven by a single actuator and composed of Theo Jansen mechanisms. The projection method is applied to derive the equations of motion of this complex mechanical system and a position control strategy based on energy is proposed. Numerical simulations validate the efficacy of the designed controller, thus setting a theoretical basis for further investigations on Theo Jansen based quadruped robots.
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Dynamic analysis and modeling of Jansen mechanism
Shunsuke Nansai, Mohan Rajesh Elara, Masami Iwase
Procedia Engineering ( Elsevier Ltd ) 64 1562 - 1571 2013.11 [Refereed]
Research paper (journal) International Co-author
Theo Jansen mechanism is gaining wide spread popularity among legged robotics researchers due to its scalable design, energy efficiency, low payload to machine load ratio, bio-inspired locomotion, deterministic foot trajectory among others. In this paper, we present dynamic analysis of a four legged Theo Jansen link mechanism using projection method that results in constraint force and equivalent Lagrange's equation of motion necessary for any meaningful extension and/or optimization of this niche mechanism. Numerical simulations using MaTX is presented in conjunction with the dynamic analysis. This research sets a theoretical basis for future investigation into Theo Jansen mechanism. © 2013 The Authors. Published by Elsevier Ltd.