Input-Shaped Model Reference Control Using Sliding Mode Design for Sway Suppression of An Industrial Overhead Crane

Input-shaped model reference control using sliding mode design is a proven method for controlling systems with parameter variations and disturbance. However, this method has never been reported for an industrial overhead crane, which is operated under nonlinear elements such as acceleration and deceleration limits caused by inverters for driving a crane in speed control mode. The successful implementation of this method will allow the crane to be operated in “hybrid mode”, which results in the fastest response from the feedforward control technique, unity magnitude zero vibration (UMZV) and tracking performance from the feedback control. This paper shows the implementation and experimental result of the input-shaped model reference control using sliding mode design for sway suppression of an industrial overhead crane. The control scheme was implemented on an industrial grade 1-ton overhead crane using a PLC and inverters. The experiments compared the control results of the UMZV and the presented control scheme on the industrial overhead crane in the cases that the system parameters are known and uncertain. When the parameters are uncertain, the presented method, with the feedback elements, provided the advantage of reducing residual vibration, while keeping the benefits of the UMZV performance

Multi-objective Anti-swing Trajectory Planning of Double-pendulum Tower Crane Operations using Opposition-based Evolutionary Algorithm

Underactuated tower crane lifting requires time-energy optimal trajectories for the trolley/slew operations and reduction of the unactuated swings resulting from the trolley/jib motion. In scenarios involving non-negligible hook mass or long rig-cable, the hook-payload unit exhibits double-pendulum behaviour, making the problem highly challenging. This article introduces an offline multi-objective anti-swing trajectory planning module for a Computer-Aided Lift Planning (CALP) system of autonomous double-pendulum tower cranes, addressing all the transient state constraints. A set of auxiliary outputs are selected by methodically analyzing the payload swing dynamics and are used to prove the differential flatness property of the crane operations. The flat outputs are parameterized via suitable B\'{e}zier curves to formulate the multi-objective trajectory optimization problems in the flat output space. A novel multi-objective evolutionary algorithm called Collective Oppositional Generalized Differential Evolution 3 (CO-GDE3) is employed as the optimizer. To obtain faster convergence and better consistency in getting a wide range of good solutions, a new population initialization strategy is integrated into the conventional GDE3. The computationally efficient initialization method incorporates various concepts of computational opposition. Statistical comparisons based on trolley and slew operations verify the superiority of convergence and reliability of CO-GDE3 over the standard GDE3. Trolley and slew operations of a collision-free lifting path computed via the path planner of the CALP system are selected for a simulation study. The simulated trajectories demonstrate that the proposed planner can produce time-energy optimal solutions, keeping all the state variables within their respective limits and restricting the hook and payload swings.Comment: 14 pages, 14 figures, 6 table

Bio-inspired robotic control in underactuation: principles for energy efficacy, dynamic compliance interactions and adaptability.

Biological systems achieve energy efficient and adaptive behaviours through extensive autologous and exogenous compliant interactions. Active dynamic compliances are created and enhanced from musculoskeletal system (joint-space) to external environment (task-space) amongst the underactuated motions. Underactuated systems with viscoelastic property are similar to these biological systems, in that their self-organisation and overall tasks must be achieved by coordinating the subsystems and dynamically interacting with the environment. One important question to raise is: How can we design control systems to achieve efficient locomotion, while adapt to dynamic conditions as the living systems do? In this thesis, a trajectory planning algorithm is developed for underactuated microrobotic systems with bio-inspired self-propulsion and viscoelastic property to achieve synchronized motion in an energy efficient, adaptive and analysable manner. The geometry of the state space of the systems is explicitly utilized, such that a synchronization of the generalized coordinates is achieved in terms of geometric relations along the desired motion trajectory. As a result, the internal dynamics complexity is sufficiently reduced, the dynamic couplings are explicitly characterised, and then the underactuated dynamics are projected onto a hyper-manifold. Following such a reduction and characterization, we arrive at mappings of system compliance and integrable second-order dynamics with the passive degrees of freedom. As such, the issue of trajectory planning is converted into convenient nonlinear geometric analysis and optimal trajectory parameterization. Solutions of the reduced dynamics and the geometric relations can be obtained through an optimal motion trajectory generator. Theoretical background of the proposed approach is presented with rigorous analysis and developed in detail for a particular example. Experimental studies are conducted to verify the effectiveness of the proposed method. Towards compliance interactions with the environment, accurate modelling or prediction of nonlinear friction forces is a nontrivial whilst challenging task. Frictional instabilities are typically required to be eliminated or compensated through efficiently designed controllers. In this work, a prediction and analysis framework is designed for the self-propelled vibro-driven system, whose locomotion greatly relies on the dynamic interactions with the nonlinear frictions. This thesis proposes a combined physics-based and analytical-based approach, in a manner that non-reversible characteristic for static friction, presliding as well as pure sliding regimes are revealed, and the frictional limit boundaries are identified. Nonlinear dynamic analysis and simulation results demonstrate good captions of experimentally observed frictional characteristics, quenching of friction-induced vibrations and satisfaction of energy requirements. The thesis also performs elaborative studies on trajectory tracking. Control schemes are designed and extended for a class of underactuated systems with concrete considerations on uncertainties and disturbances. They include a collocated partial feedback control scheme, and an adaptive variable structure control scheme with an elaborately designed auxiliary control variable. Generically, adaptive control schemes using neural networks are designed to ensure trajectory tracking. Theoretical background of these methods is presented with rigorous analysis and developed in detail for particular examples. The schemes promote the utilization of linear filters in the control input to improve the system robustness. Asymptotic stability and convergence of time-varying reference trajectories for the system dynamics are shown by means of Lyapunov synthesis

Integrated sensing, dynamics and control of a moble gantry crane

This thesis investigates the dynamics and control of a Rubber Tyred Gantry (RTG) crane which is commonly used in container handling operations. Both theoretical and experimental work has been undertaken to ensure the balance of this research. The concept of a Global Sensing System (GSS) is outlined, this being a closed loop automatic sensing system capable of guiding the lifting gear (spreader) to the location of the target container by using feedback signals from the crane's degrees of freedom. To acquire the crucial data for the coordinates and orientation of the swinging spreader a novel visual sensing system (VSS) is proposed. In addition algorithms used in the VSS for seeking the central coordinates of the clustered pixels from the digitised images are also developed. In order to investigate the feasibility of different control strategies in practice, a scaleddown, 1/8 full size, experimental crane rig has been constructed with a new level of functionality in that the spreader in this rig is equipped with multiple cables to emulate the characteristics of a full-size RTG crane. A Crane Application Programming Interface (CAPI) is proposed to reduce the complexity and difficulty in integrating the control software and hardware. It provides a relatively user-friendly environment in which the end-user can focus on implementing the more fundamental issues of control strategies, rather than spending significant amounts of time in low-level devicedependent programming. A control strategy using Feedback Linearization Control (FLC) is investigated. This can handle significant non-linearity in the dynamics of the RTG crane. Simulation results are provided, and so by means of the CAPI this controller is available for direct control of the experimental crane rig. The final part of the thesis is an integration of the analyses of the different subjects, and shows the feasibility of real-time implementation

有段変速クレーンの高速制振搬送に関する研究

クレーンによる吊り荷の高速自動搬送には，高度な自動制御技術が求められる．ワイヤロープを用いて玉掛けした吊り荷を，クラブトロリの巻き上げ装置を用いて吊り上げたあと，駆動装置によって目的地に向けて搬送すると，クラブトロリの加減速によって吊り荷に振り子運動が生じる．このとき，制振制御を考慮せずに目的地の直上まで搬送した場合，目的地に到着したあとも吊り荷には振れが残留する．このため，すぐに吊り荷を地面に着地させることができず，クレーンの総運搬時間が長くなり，運搬効率の低下を招く．したがって，クレーンで吊り荷の高速自動搬送を行うとき，吊り荷の振り子運動を制御して，目的地で振れを収束させるための制振制御技術が必要である．これまで，制振制御に関するさまざまな方法が提案されているが，トロリの駆動システムに加速度一定の制約を持つクレーンに対する制振制御法は報告されていない．このようなシステムは旧式の有段変速クレーンに多く採用されており，リレー回路によるOn/Off指令でトロリが駆動される．そこで本論文では，トロリ駆動システムに加速度一定の制約をもつクレーンに適用可能な，新たなフィードフォワード(FF)制振制御法を提案する．本手法は，時間多項式によるFF制御法(FFT)に基づき，制約条件を考慮するためにFFT法により生成した制御入力をパルス幅変調法(PWM)により近似する．FFT法は線形近似モデルによりFF制御入力を生成するためモデル化誤差が生じる．また，生成した制御入力をPWM制御入力で近似するため量子化誤差が生じる．これらの誤差の影響に対してロバストな制御入力を生成するアルゴリズムとして更新型FFT法(UFFT)と総当たり更新型FFT法(NSFTC)を構築した．これらは，残留振れが小さくなるように制御入力を繰り返し計算するアルゴリズムであり，シミュレーションによる性能評価によって，FFT法より有効な制振制御法であることを確認した．さらに，FFT法に比べてUFFT法が有効な制御法であることを，実験評価用クレーンを利用して実証した．実験ではさらに，吊り荷の質量変化に対してロバストな制御入力も探索できることを確認した．以上，本論文では，クレーントロリの駆動システムに加速度一定の制約を持つ有段変速クレーンにおいて，高速制振搬送のためのFF制御入力を生成できる新たなアルゴリズムを提案し，その有効性をシミュレーションと実験で明らかにした．Advanced automatic control technology is required for high-speed automatic transport of suspended loads by cranes. When a suspended load slung by a wire rope is lifted by a hoisting device of a crane\u27s club trolley and transported to a destination by a driving device at high speed, a pendulum motion is caused by the acceleration and deceleration of the trolley. If the trolley is moved above the destination without considering sway control, the load continues to oscillate even after arrival. Therefore, the load cannot be immediately unloaded, and the crane transportation time increases, resulting in a deterioration in yard productivity. High-speed automatic transfer of suspended load by crane requires technology to sway control. A number of crane control methods have been proposed in the past. However, if the drive system of the crane has restrictions, the conventional anti-sway control method may not be directly applicable. This type of system is used for many older cranes which are driven of multistep speed by on/off relay circuits. In this study, we propose a feedforward (FF) control input generation method that can realize automatic anti-sway transport of a suspended load for a crane system with restrictions that the trolley can only accelerate or decelerate at a constant rate; the switching frequency of the acceleration input cannot be too high. The proposed method combines the FF control input generation using the time-polynomial (FFT) method and pulse width modulation (PWM) control. In the FFT method, the derived FF control input may be unable to suppress the swing of the suspended load because of the modeling error in deriving the FF control input and the quantization error in approximating the FF control input by the PWM control input. To solve these problems, we propose two algorisms. First algorism is the update type FF control input generation using the time-polynomial (UFFT) method, second algorism is the neo-style FF control input generation using the time-polynomial (NSFTC) method, both of which evaluates the residual sway at a constant time interval and updates the original FF control input derived by the FFT method. The effectiveness of these methods is confirmed through simulations. Moreover, the effectiveness of the UFFT method is experimentally confirmed, and it is also confirmed that a control input that is robust to the mass variation of the suspended load can be easily explored. In conclusion, we propose the new FF control input generation algorithms for high speed transfer in a multi-step speed operation crane.室蘭工業大学 (Muroran Institute of Technology)博士（工学

Advanced Mathematics and Computational Applications in Control Systems Engineering

Control system engineering is a multidisciplinary discipline that applies automatic control theory to design systems with desired behaviors in control environments. Automatic control theory has played a vital role in the advancement of engineering and science. It has become an essential and integral part of modern industrial and manufacturing processes. Today, the requirements for control precision have increased, and real systems have become more complex. In control engineering and all other engineering disciplines, the impact of advanced mathematical and computational methods is rapidly increasing. Advanced mathematical methods are needed because real-world control systems need to comply with several conditions related to product quality and safety constraints that have to be taken into account in the problem formulation. Conversely, the increment in mathematical complexity has an impact on the computational aspects related to numerical simulation and practical implementation of the algorithms, where a balance must also be maintained between implementation costs and the performance of the control system. This book is a comprehensive set of articles reflecting recent advances in developing and applying advanced mathematics and computational applications in control system engineering

15th Conference on Dynamical Systems Theory and Applications DSTA 2019 ABSTRACTS

From Preface: This is the fifteen time when the conference „Dynamical Systems – Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and the Ministry of Science and Higher Education. It is a great pleasure that our invitation has been accepted by so many people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcome nearly 255 persons from 47 countries all over the world. They decided to share the results of their research and many years experiences in the discipline of dynamical systems by submitting many very interesting papers. This booklet contains a collection of 338 abstracts, which have gained the acceptance of referees and have been qualified for publication in the conference edited books.Technical editor and cover design: Kaźmierczak, MarekCover design: Ogińska, Ewelina; Kaźmierczak, Mare

Time Localization of Abrupt Changes in Cutting Process using Hilbert Huang Transform

Cutting process is extremely dynamical process influenced by different phenomena such as chip formation, dynamical responses and condition of machining system elements. Different phenomena in cutting zone have signatures in different frequency bands in signal acquired during process monitoring. The time localization of signal’s frequency content is very important. An emerging technique for simultaneous analysis of the signal in time and frequency domain that can be used for time localization of frequency is Hilbert Huang Transform (HHT). It is based on empirical mode decomposition (EMD) of the signal into intrinsic mode functions (IMFs) as simple oscillatory modes. IMFs obtained using EMD can be processed using Hilbert Transform and instantaneous frequency of the signal can be computed. This paper gives a methodology for time localization of cutting process stop during intermittent turning. Cutting process stop leads to abrupt changes in acquired signal correlated to certain frequency band. The frequency band related to abrupt changes is localized in time using HHT. The potentials and limitations of HHT application in machining process monitoring are shown