Implementation of gaits for achieving omnidirectional walking in a quadruped robot
TL;DR: The proposed modified crawl gait is compared to the conventional method with respect to the above parameters geometrically as well as mathematically and is shown to have positive stability margin at all times.
Abstract: In this paper, we propose a better planning technique of the standard walking gaits for a quadruped robot than the conventional successive gait transition method to realize omnidirectional static walking. The technique involved planning the sequence as well as motion of the swinging and supporting legs. The relationship between the stability margin, the stride length and the duty factor are also formulated mathematically. The proposed modified crawl gait is compared to the conventional method with respect to the above parameters geometrically as well as mathematically and is shown to have positive stability margin at all times. The successive gait transition is demonstrated on the modified crawl and rotation gaits. Computer simulations of a model quadruped robot were performed to validate the theory proposed. Experiments were performed on an actual quadruped robot to realize the omnidirectional static walking with increased stability margin.
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Patent•
15 Aug 2017
TL;DR: In this paper, a quadruped robot control method and control device on the basis of a sine opposite angle gait and a quick table look-up method was proposed, where the table lookup method is adopted to quickly, accurately and stably carry out the foot end trajectory control.
Abstract: The invention relates to a quadruped robot control method and control device on the basis of a sine opposite angle gait and a quick table look-up method. The method comprises the following steps that: (1) combining with the opposite angle gait to analyze the leg structure of a quadruped robot, establishing the leg movement mathematical model of the quadruped robot, and adopting a novel sine gait; (2) solving a nonlinear equation set to obtain the control rate of each joint of four limbs, establishing a database which specially faces robot movement control, obtaining an accurate joint opening and closing angle through the quick table look-up method, and quickly and accurately realizing foot end trajectory control; and (3) designing a foot end trajectory control unit and a steering control unit so as to bring convenience to the access of other control systems. On an aspect of trafficability characteristics, the novel sine gait is designed and adopted, and therefore, and the robot owns high trafficability when the robot faces a complex terrain. On the aspect of operation stability, when a step taking period stops, the horizontal speed of a swing phase is zero, and therefore, the method is high in stability. The table look-up method is adopted to quickly, accurately and stably carry out the foot end trajectory control.
4 citations
01 Dec 2017
TL;DR: The quadruped robot kinematic model of the forward and inverse kinematics for each 3-DOF leg has been calculated which leading to find the minimum stability margins during walking on the vertical geometrical projection of the robot body.
Abstract: The potential ability of the quadruped (four-legged) robot locomotion has been used for many different applications such as walking over soft and rough terrains. These applications are needed to grantee the mobility and flexibility. Generally, quadruped robots have three main periodic gaits: creeping gait, running gait and galloping gait. The stability criteria is the main problem of the quadruped robot during walking with a slow motion gait such as creeping gait. The static stability gait is completely depends on the stability margins during the walking which have been calculated in this paper. The quadruped robot kinematic model of the forward and inverse kinematics for each 3-DOF leg has been calculated which leading to find the minimum stability margins during walking on the vertical geometrical projection of the robot body. These margins are needed to be optimized for achieving the best stability margin during the robot walking.in this paper we using the PSO optimization algorithm to find the best value of the stability margin. Simulation and results verify the stability margin range values and the optimized results.
3 citations
TL;DR: In this article, the authors proposed a framework to improve the stability of stability in the field of health care by using the concept of stability index (SINR) which is a measure of the health status of a patient.
Abstract: الكوادروبيد ربوت هو روبوت رباعي الارجل له القابلية على القيام بمهمات عديدة منها المشي والانتقال على الارض المسطحة فضلا عن قدرته على المشي على الارض الوعرة. يقوم هذا الروبت على محاكاة الحيوانات او الحشرات رباعية الارجل من خلال تقليد الحركات التي تقوم بها هذه الحيوانات. إن من أشهر الحركات التي يستخدمها هذا الروبوت في الانتقال هي: المشي والركض والركض مع القفز. ان حركة المشي التي تم تنفيذها في هذه الورقة هي عبارة عن تحريك رجل واحدة بعد الاخرى خلال مدة زمنية معينة وبعد وصول الرجل الى المكان المناسب تبدأ رجل اخرى بالحركة. يستخدم هذا الايقاع في الحركة لكي نضمن بقاء ثلاثة أرجل ملتصقة على الارض لتحقيق الاستقرارية خلال مدة انتقال الرجل المرفوعة. خلال عملية رفع احدى الارجل سوف يتكون مثلث ناتج من اسقاط نقاط تثبيت بقية الارجل الثلاث مع سنتر الروبوت على الارض.ان مهمة هذا الروبوت هو البقاء مستقرا خلال هذه الحركات لذلك يحتاج الى تحليل الاستقرارية عن طريق حساب الـ (Stability Margins) في هذه الورقة ايضا تم تحليل حركة الروبوت بالنسبة للمشي البطيء(Creeping Gait) ومن ثم حساب معادلات الكاينماتيك الخاصة للحصول على موقع الارجل على الارض واللازمة لتحقيق الاستقرارية الثابتة للروبوت اثناء المشي. ومن بعدها تم الحصول على النتائج اللازمة لتحقيق هذه الاستقرارية من خلال مواقع الارجل على الارض.
3 citations
Cites background from "Implementation of gaits for achievi..."
...These systems present better adaptability over wheeled systems, particularly when dealing with irregular territories [1]....
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Journal Article•
TL;DR: In this article, the PSO optimization algorithm was used to find the minimum stability margin with walking on the vertical projection of the robot geometrical body for quadruped robot locomotion.
Abstract: The ability of the quadruped (four-legged) robot locomotion was used in a lot of different applications like walking over soft and rough terrains. These applications needed to guarantee the flexibility and mobility. Generally, quadruped robots have three basic periodic gaits: creeping gait, running gait and galloping gait. The stability criteria are the main issue of the quadruped robot throughout walking with the slow motion gait like creeping gait. The gait of static stability is completely bases on the stability margins in the walking that was calculated in this paper. The quadruped robot legs walking sequence and creeping gait within the leg fixing and swinging phases carried out. The kinematics model of quadruped robot of the forward and inverse kinematics for each leg 3-DOF was calculated that lead to discover the minimum stability margins with walking on the vertical projection of the robot geometrical body. These stability margins needed to be optimized in order to obtain the best stability margin throughout this robot walking. In this paper we use the PSO optimization algorithm to get the best stability margins value. Simulation and results are verified the range of the stability margin values and the optimized results.
2 citations
Cites background from "Implementation of gaits for achievi..."
...These systems adapted their ability in order to deal with irregular territories especially when compared with wheel systems [1]....
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15 Apr 2020
TL;DR: This paper proposes an open-source low-cost quadruped robot that employs a ROS framework to give the learner the necessary tools to develop a basic autonomous robot, capable of mapping its surroundings while avoiding obstacles.
Abstract: The use of legged robots in non-uniform terrains is a deeply studied subject, as they are capable of performing activities such as exploration, monitoring, and collection in places where other solutions present serious disadvantages. However, most of these robots are too expensive and complex for young researchers and students to develop their algorithms and test them in a standardized model. In contrast, we propose an open-source low-cost quadruped robot that employs a ROS framework to give the learner the necessary tools to develop a basic autonomous robot, capable of mapping its surroundings while avoiding obstacles. This paper presents the details of the whole development process, which includes the motion of the robot, achieved using quadratic optimization and static stability of the center of gravity, a LiDAR-based SLAM system, and path planning using the A* algorithm. Simulation and testing show that the robot is capable of successfully achieving the tasks with responsive and natural movements.
1 citations
Cites background from "Implementation of gaits for achievi..."
...This sequence is based on static stability; that is, for the robot to be stable in each step, the center of gravity (CoG) must always be kept within the support polygon formed by the contact points of the remaining legs on the ground [15]....
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References
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TL;DR: Research carried out on locomotor central pattern generators (CPGs), i.e. neural circuits capable of producing coordinated patterns of high-dimensional rhythmic output signals while receiving only simple, low-dimensional, input signals, is reviewed.
1,737 citations
"Implementation of gaits for achievi..." refers methods in this paper
...Mimicking biological walking patterns also requires mimicking of their control principles, such as Neural Networks and Central Pattern Generators discussed in [4] and [5]....
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TL;DR: The mission at Boston Dynamics is to develop a new breed of rough-terrain robots that capture the mobility, autonomy and speed of living creatures, which will travel in outdoor terrain that is too steep, rutted, rocky, wet, muddy, and snowy for conventional vehicles.
1,380 citations
"Implementation of gaits for achievi..." refers background in this paper
...Use of a sophisticated sensing and feedback system to determine gait characteristics has been demonstrated by [4] and [2]....
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TL;DR: The trade-off problem between the stability and the energy consumption in determining the cyclic period of walking on irregular terrain is pointed out, and one example is shown to solve this problem.
Abstract: We have been trying to induce a quadruped robot to walk with medium walking speed on irregular terrain based on biological concepts. We propose the necessary conditions for stable dynamic walking on irregular terrain in general, and we design the mechanical system and the neural system by comparing biological concepts with those necessary conditions described in physical terms. A PD controller at the joints can construct the virtual spring-damper system as the visco-elasticity model of a muscle. The neural system model consists of a central pattern generator (CPG) and reflexes. A CPG receives sensory input and changes the period of its own active phase. The desired angle and P-gain of each joint in the virtual spring-damper system is switched based on the phase signal of the CPG. CPGs, the motion of the virtual spring-damper system of each leg and the rolling motion of the body are mutually entrained through the rolling motion feedback to CPGs, and can generate adaptive walking. We report on our experimen...
665 citations
"Implementation of gaits for achievi..." refers background or methods in this paper
...Use of a sophisticated sensing and feedback system to determine gait characteristics has been demonstrated by [4] and [2]....
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...[4] describes a robust quadruped walking system that relies on complex mechanical and control structures....
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...Mimicking biological walking patterns also requires mimicking of their control principles, such as Neural Networks and Central Pattern Generators discussed in [4] and [5]....
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TL;DR: In this paper, a mathematical analysis showed that for only three of the six possible quadruped crawl gaits, it is possible to place the feet of an animal or machine so that it is statically stable at all times.
Abstract: While the total number of theoretically possible quadruped gaits is quite large, only six gaits have the property that they can be executed while keeping at least three feet on the ground at all times. These gaits, called creeping gaits, seem to be well suited for low-speed locomotion since they permit a quadruped to remain statically stable during most of a locomotion cycle. A mathematical analysis shows, however, that for only three of the six creeping gaits it is possible to place the feet of an animal or machine so that it is statically stable at all times. Furthermore, among these three, there exists a unique optimum gait that maximizes static stability. This gait corresponds to the normal quadruped crawl favored by most animals for very low-speed locomotion.
588 citations
"Implementation of gaits for achievi..." refers background in this paper
...stability and efficiency has been performed in [10]....
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10 Apr 2007
TL;DR: A controller for a quadrupedal robot statically walking on known rough terrain has both deliberative and reactive components for task specific control issues, such as impassable terrain and unmodeled foot slippage.
Abstract: We present a controller for a quadrupedal robot statically walking on known rough terrain. The controller has both deliberative and reactive components for task specific control issues, such as impassable terrain and unmodeled foot slippage. The controller architecture supports multiple gaits, and we present both a stable omnidirectional gait and a faster directional gait. The robot successfully negotiates obstacles up to 7.5 cm (ap40% leg length) tall and navigates over rocky terrain.
167 citations