This thesis sets up terrain parameters and locomotion strategies of a hexapod robot walking on variable and discontinuous terrain. Walking on this kind of terrain is the greatest advantage of legged robots compared with wheeled robots. First, establish a randomly distributed parameterized terrain. Second, set up morphological parameters and dimension parameters of the robot. Third, build kinematic model and generate continuous gaits of the robot, including crab gaits and turning gaits. The locomotion strategy can determine every AEP ,PEP and stride depending on terrain. Finally, verify the strategy through computer programming and find shorter path by calculating if foothold is available in advance. Because of applying randomly distributed parameterized terrain, in addition to describing the terrain more comprehensively, the terrain parameters can be adjusted easily according to different needs. This research will bring about more applications and developments of legged robots.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This paper presents an alternative solution to improve the locomotion system of a hexapod robot by artificial intelligence. Through an optimal design to achieve static stability, dynamic stability and optimize energy consumption through an autonomous system that is able to perform trajectories without any inconvenience. For the robot to move without flaws has certain restrictions in design (weight, size, materials, etc.) The hexapod has a high degree of movement and this allows many trajectories handle at the time of travel. Using sensors under certain working conditions we will obtain the necessary data and signals to satisfactorily comply with the hexapod robot design. / Revisión por pares

No description available.

The Defence, Peace, Safety and Security (DPSS) competency area within the Council for Scientific and Industrial Research (CSIR) has identified the need for the development of a robot that can operate in almost any land-based environment. Legged robots, especially hexapod (six-legged) robots present a wide variety of advantages that can be utilised in this environment and is identified as a feasible solution. The biggest advantage and main reason for the development of legged robots over mobile (wheeled) robots, is their ability to navigate in uneven, unstructured terrain. However, due to the complicated control algorithms needed by a legged robot, most literature only focus on navigation in even or relatively even terrains. This is seen as the main limitation with regards to the development of legged robot applications. For navigation in unstructured terrain, postural controllers of legged robots need fast and precise knowledge about the state of the robot they are regulating. The speed and accuracy of the state estimation of a legged robot is therefore very important. Even though state estimation for mobile robots has been studied thoroughly, limited research is available on state estimation with regards to legged robots. Compared to mobile robots, locomotion of legged robots make use of intermitted ground contacts. Therefore, stability is a main concern when navigating in unstructured terrain. In order to control the stability of a legged robot, six degrees of freedom information is needed about the base of the robot platform. This information needs to be estimated using measurements from the robot’s sensory system. A sensory system of a robot usually consist of multiple sensory devices on board of the robot. However, legged robots have limited payload capacities and therefore the amount of sensory devices on a legged robot platform should be kept to a minimum. Furthermore, exteroceptive sensory devices commonly used in state estimation, such as a GPS or cameras, are not suitable when navigating in unstructured and unknown terrain. The control and localisation of a legged robot should therefore only depend on proprioceptive sensors. The need for the development of a reliable state estimation framework (that only relies on proprioceptive information) for a low-cost, commonly available hexapod robot is identified. This will accelerate the process for control algorithm development. In this study this need is addressed. Common proprioceptive sensors are integrated on a commercial low-cost hexapod robot to develop the robot platform used in this study. A state estimation framework for legged robots is used to develop a state estimation methodology for the hexapod platform. A kinematic model is also derived and verified for the platform, and measurement models are derived to address possible errors and noise in sensor measurements. The state estimation methodology makes use of an Extended Kalman filter to fuse the robots kinematics with measurements from an IMU. The needed state estimation equations are also derived and implemented in Matlab®. The state estimation methodology developed is then tested with multiple experiments using the robot platform. In these experiments the robot platform captures the sensory data with a data acquisition method developed while it is being tracked with a Vicon motion capturing system. The sensor data is then used as an input to the state estimation equations in Matlab® and the results are compared to the ground-truth measurement outputs of the Vicon system. The results of these experiments show very accurate estimation of the robot and therefore validate the state estimation methodology and this study. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

The Defence, Peace, Safety and Security (DPSS) competency area within the Council for Scientific and Industrial Research (CSIR) has identified the need for the development of a robot that can operate in almost any land-based environment. Legged robots, especially hexapod (six-legged) robots present a wide variety of advantages that can be utilised in this environment and is identified as a feasible solution. The biggest advantage and main reason for the development of legged robots over mobile (wheeled) robots, is their ability to navigate in uneven, unstructured terrain. However, due to the complicated control algorithms needed by a legged robot, most literature only focus on navigation in even or relatively even terrains. This is seen as the main limitation with regards to the development of legged robot applications. For navigation in unstructured terrain, postural controllers of legged robots need fast and precise knowledge about the state of the robot they are regulating. The speed and accuracy of the state estimation of a legged robot is therefore very important. Even though state estimation for mobile robots has been studied thoroughly, limited research is available on state estimation with regards to legged robots. Compared to mobile robots, locomotion of legged robots make use of intermitted ground contacts. Therefore, stability is a main concern when navigating in unstructured terrain. In order to control the stability of a legged robot, six degrees of freedom information is needed about the base of the robot platform. This information needs to be estimated using measurements from the robot’s sensory system. A sensory system of a robot usually consist of multiple sensory devices on board of the robot. However, legged robots have limited payload capacities and therefore the amount of sensory devices on a legged robot platform should be kept to a minimum. Furthermore, exteroceptive sensory devices commonly used in state estimation, such as a GPS or cameras, are not suitable when navigating in unstructured and unknown terrain. The control and localisation of a legged robot should therefore only depend on proprioceptive sensors. The need for the development of a reliable state estimation framework (that only relies on proprioceptive information) for a low-cost, commonly available hexapod robot is identified. This will accelerate the process for control algorithm development. In this study this need is addressed. Common proprioceptive sensors are integrated on a commercial low-cost hexapod robot to develop the robot platform used in this study. A state estimation framework for legged robots is used to develop a state estimation methodology for the hexapod platform. A kinematic model is also derived and verified for the platform, and measurement models are derived to address possible errors and noise in sensor measurements. The state estimation methodology makes use of an Extended Kalman filter to fuse the robots kinematics with measurements from an IMU. The needed state estimation equations are also derived and implemented in Matlab®. The state estimation methodology developed is then tested with multiple experiments using the robot platform. In these experiments the robot platform captures the sensory data with a data acquisition method developed while it is being tracked with a Vicon motion capturing system. The sensor data is then used as an input to the state estimation equations in Matlab® and the results are compared to the ground-truth measurement outputs of the Vicon system. The results of these experiments show very accurate estimation of the robot and therefore validate the state estimation methodology and this study. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18946号 / 工博第3988号 / 新制||工||1614 / 31897 / 京都大学大学院工学研究科航空宇宙工学専攻 / (主査)教授 泉田 啓, 教授 藤本 健治, 教授 松野 文俊 / 学位規則第4条第1項該当

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18946号 / 工博第3988号 / 新制||工||1614(附属図書館) / 31897 / 京都大学大学院工学研究科航空宇宙工学専攻 / (主査)教授 泉田 啓, 教授 藤本 健治, 教授 松野 文俊 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

No description available.

Baigiamajame magistro darbe nagrinėjamas šešiakojo roboto judėjimas. Pateikiami vienos kojos atvirkštinės kinematikos uždavinio sprendimai Denavito ir Hartenbergo bei geometriniu metodais. Analizuojamas vienos kojos trajektorijos sudarymo metodas ir pateikiams jos aprašymo būdas. Pateikiami galimi trajektorijų pavyzdžiai. Sudaroma trikojės roboto eisenos seka bei diagrama. Darbe pateikiamas roboto valdymo algoritmas ir valdymo programa, atsižvelgiant į apibrėžtus variklių valdymo kriterijus. Eksperimentiškai tiriamas roboto judėjimas lygiu paviršiumi taikant trikoję eiseną. Pagal rezultatus koreguojama eisena. Atliekami trajektorijos pakartojimo tikslumo bandymai. Įvertinus rezultatus pateikiamos baigiamojo darbo išvados ir pasiūlymai. / Hexapod robot locomotion is analyzed in this paper. Inverse kinematics solutions are proposed for one leg using Denavit-Hartenberg and geometric methods. Trajectory forming for one leg is analyzed and solution for delineating trajectory is introduced. Possible leg trajectory examples are presented. Tripod gait sequence and diagram is designed for robot. Work presents robot control algorithm and program according to motor control parameters. Robot locomotion over regular terrain using tripod gait is tested. Gait then is corrected according to test results. Tests are made for trajectory repeating accuracy. Conclusions and solutions are made according to results.

The diploma thesis deals with the construction of a walking mobile robot, which is intended for passing through a rugged or forest terrain, whose task is to collect the sample. The first part is devoted to the review of walking robots. Follow-up an analysis of two-legged and four-leg walking robot technologies and a brief overview of drives. The second part is devoted to problem analysis and design variant. The work contains 4 design variants in the form of schemes. Using the multi-criteria analysis, the variants were evaluated and the optimal variant was chosen taking into account the representative parameters. The third part is devoted to the construction of the chosen variant, it is divided into body and leg construction. The overall design is processed in the form of a virtual 3D model. In the leg construction, the design itself, but also the calculations of drives, shafts, gears and belt transmissions are solved. The end of the thesis is devoted to drawing documentation based on 3D model and economic evaluation. Follow-up and discussion with possible continuation and use in practice.