Robotic contour tracking with adaptive feedforward control by fuzzy online tuning

Industrial robots have great importance in manufacturing. Typical uses of the robots are welding, painting, deburring, grinding, polishing and shape recovery. Most of these tasks such as grinding, deburring need force control to achieve high performance. These tasks involve contour following. Contour following is a challenging task because in many of applications the geometry physical of the targeted contour are unknown. In addition to that, achieving tasks as polishing, grinding and deburring requires small force and velocity tracking errors. In order to accomplish these tasks, disturbances have to be taken account. In this thesis the aim is to achieve contour tracking with using fuzzy online tuning. The fuzzy method is proposed in this thesis to adjust a feedforward force control parameter. In this technique, the varying feedforward control parameter compensates for disturbance effects. The method employs the chattering of control signal and the normal force and tangential velocity errors to adjust the control term. Simulations with the model of a direct drive planar elbow manipulator are used to last proposed technique

Dört bacaklı robotlarda merkezi örüntü üreteci ve genetik algoritmalar ile referans sentezi

Bu çalışmada Merkezi Örüntü Üretimi (MÖÜ) ile referansları sentezlenen dört bacaklı robotun dengeli yürüyüşü önerilmiştir. MÖÜ biyolojiden ilham alınarak oluşturulan bir referans sentezi yöntemidir. Bu yöntemde kullanılan uygun parametleri belirlemek, robotun düşmesini engellemek için önemlidir. Çalışmamızda bu parametreleri belirlemek için yine biyolojiden ilham alınarak oluşturulan Genetik Algoritma (GA) optimizasyon yöntemi kullanılmıştır. Genetik Algoritma’nın amaç fonksiyonu denge ve enerji tüketimi olarak seçilmiştir. MÖÜ yöntemi ile üretilen referanslar, 16 serbestlik dereceli dört bacaklı robotumuza üç boyutlu (3D) tam dinamikli benzetim ortamında uygulanmıştır. Benzetim sonuçları önerilen metodun geçerliliğini kanıtlamıştır

Dört bacaklı robotlar için önizleme kontrolü ve sıfır moment noktası esaslı yürüyüş yörüngesi üretimi

Robota verilen görevde engel aşımı gerektiğinde bacaklı robotların geri kalan mobil robotlara göre önemli avantajları bulunmaktadır. Bu makalede dört bacaklı robotların düz bir yüzeyde yürüyüşü için bir ölçümleme üretimi yöntemi sunuldu. Bu yaklaşım sıfır moment noktası (SMN) temelli kararlılık ve doğrusal ters sarkaç modeli (DTSM) üzerinedir. Yürüyüş için SMN referans gezingeleri ileri sürülüp oradan önizleme kontorü vasıtasıyla robotun ağırlık merkezi (RAM) referansı için referans gezingeleri elde edildi. Bacak eklemlerinin pozisyonları RAM referans gezingeleri üzerine ters kinematik uygulanarak hesaplandı. Öne sürülen referans gezinge üretimi sentezi, tamamen dinamik 3 boyutlu benzetimle test edildi. Benzetimde 16 serbestlik derecesine (SD) sahip dört bacaklı robot modeli kullanıldı. Benzetim sonuçları, yürüyüş için yapılan referans üretim tekniğinin başarıya ulaştığını gösteriyor

Trajectory generation for flight phase of a quadruped robot jump

Legged robots excel in navigating challenging natural environments, such as steep obstructions or wide gaps in the ground. Apart from rough terrain, they may confront unexpected impact forces during their leaping gaits. While facing external disturbances, legged robots should maintain and restore their stability while completing their gaits. External disturbances and body orientation errors should be identified. Appropriate actions have to be taken to restore the balance of the robot and provide advantageous landing circumstances. This dissertation examines the robot body orientation errors during the flight phase and first offers a unique posture control method that uses reinforcement learning to build reference trajectories for a quadrupedal robot with waist joints during a long jump flight phase. Then, another novel algorithm for posture recovery is provided, this time based on angular momentum. The same algorithm is altered to account for perturbations in the flying phase caused by a push on the robot’s body. We describe a push recovery method that uses angular momentum to build reference trajectories for the long jump. This work also contains a more detailed angular momentum-based reference generating approach for posture recovery. Real-time centroidal dynamics computation is employed in this second technique. These approaches provide reference trajectories for the waist and rear hip joints of the quadrupedal robot in order to acquire the desired orientation of the robot in the air. PID joint position control is used to track reference trajectories. The robot model used in the calculations is comprehensive since each component of the robot’s body—the leg links and three torso portions—is represented by individual parameters. The suggested techniques for trajectory creation are computationally efficient, making them suited for use in real-time applications. The proposed posture control and push recovery approaches are tested on the model of a quadrupedal robot during the flight phase of a long jump via simulations. The findings reveal that the proposed methods are accurate in terms of angular position and angular velocity regulation and can achieve successful landing postures

Balance and posture control of legged robots: a survey

Legged robots excel in navigating challenging natural environments, such as steep obstructions or wide gaps in the ground. In addition to rough terrain, they may confront unexpected impact forces during their leaping gaits. While facing external disturbances, legged robots should maintain and (if necessary) restore their stability while completing their gaits. To this end, external disturbances and body orientation errors should be identified, and appropriate actions have to be taken to restore the balance of the robot and to provide advantageous landing circumstances. This paper briefly surveys the developments for balance and posture control of legged robots. The primary focus of these studies is on balancing legged robots under external disturbances or performing dynamic gaits. This paper also includes a brief focus on the literature that present research on balance and posture control strategies using the angular momentum approach

Genetically optimized pitch angle controller of a wind turbine with fuzzy logic design approach

An important engineering challenge is the design of a wind turbine’s pitch angle controller. The dependability, safety, and power output maximization of a wind turbine are all impacted by this controller. In this study, a 2 MW doubly fed induction generator wind turbine’s blade angle controller design with a novel fuzzy logic controller is tested in a simulated environment. The evolutionary algorithm technique is used to optimize the fuzzy logic controller with three inputs. A genetic algorithm is used to optimize the specified pitch angle controller for a number of coefficients. After the optimization process, the controller’s performance is assessed in terms of power output, overshoot, and steady-state error characteristics

Hybrid force-motion control for one-legged robot in operational space

This paper presents a dynamic locomotion generation for a one-legged floating-base robot. Reference synthesis is performed by planning both swing motion of the foot and contact forces acting from the ground. A fifth-order polynomial is employed as the position reference to reduce the impact forces and ensure a steady transition between the swing and stance phases. Contact force references are designed utilizing the laws of momentum conservation and impulse. A hybrid force-motion control framework is created in the operational space for tracking generated references. Gait phase transition is proposed to assist the transition between the force and motion controller. A full-dynamics simulation environment is utilized to test the proposed control framework. Results supported the competence of the proposed control framework for the floating-base one-legged robot

Push recovery of a quadrupedal robot in the flight phase of a long jump

Legged robots are well-suited for operation in challenging natural environments, such as steep obstacles or vast gaps in the ground. Aside from difficult terrain, robots may also encounter unanticipated impact forces while performing jumping gaits. When performing their gaits, legged robots should be able to maintain and regain their stability in the face of external perturbations. External disturbances should be detected, and necessary actions should be taken to maintain the robot's balance in order to ensure optimum landing conditions. This paper considers flight phase disturbances in the form of a push on the robot body and introduces a novel push recovery algorithm that uses angular momentum to generate reference trajectories for a quadrupedal robot with waist joints during the flight phase of a long jump. This method creates joint position reference trajectories for the quadrupedal robot's waist and rear hip joints in order to achieve the required orientation of the robot in the air. In order to track reference trajectories, PID joint control is utilized. The robot model employed for the computations is comprehensive because components of the robot body - the leg links and three torso sections - are represented with independent mass values. The proposed push recovery trajectory generation approach is computationally efficient and hence suitable to be employed in real-time applications. The suggested method is used to simulate a quadrupedal robot to test the push recovery algorithm following external disturbances in the flight phase of a long jump. The results demonstrate that the suggested approach performs well in terms of angular position and angular velocity accuracy and it can achieve a posture suitable for landing

2MW rüzgar türbini için kanat açısı kontrolörleri P, PI, PID ve optimize edilmiş PID'nin performans karşılaştırması [Performance comparison of pitch angle controllers P, PI, PID and optimized PID for 2MW wind turbine]

Bu çalışma, Matlab Simulink ortamında 2MW DFIG tipi bir rüzgar türbini üzerinde üç farklı kanat açı kontrolörünün etkilerini sunmaktadır. Kanat açı kontrolörünün temel amacı, kontrolörün girişi jeneratör hızı olduğu için rotor ve jeneratör hızını düzenlemektir, burada kontrolörün çıkışı kanat açısını belirlemektir. Türbinin kanat açı kontrolörünü tasarlamak için P, PI, PID ve optimize edilmiş PID kontrol metodolojileri kullanıldı. PID kontrolör için kullanılan optimizasyon yöntemi genetik algoritmadır. Kontrolör tasarımı sayesinde karşılaştırma parametreleri için yinelemeler, oturma zamanı, aşma değeri, hata değerleri ve güç çıkış değerleri hesaplandı ve geçici ve kalıcı konum açısından tüm kontrolör performansları değerlendirildi

Whole-body pace gait control based on centroidal dynamics of a quadruped robot

This paper studies the full-body motion generation of a quadruped robot for pace gait. A motion planning algorithm is designed based on the centroidal dynamics of the robot. The motion planning algorithm generates both position and force reference trajectories. These reference trajectories serve as a guide for the swing motion of feet during the swing phase, while they also serve as a guide for the ground contact forces during the stance phase. A hybrid force-motion control framework is constructed using the operational space formulation (OSF) in order to track generated reference trajectories. We contribute further to the OSF of floating-base robots by decoupling the dynamics of the right and left leg pairs to facilitate pace gait. The proposed motion generation method for pace gait is validated using a full-dynamics simulation environment. The results reveal the competence of the proposed whole-body pace gait control for a quadruped robot