Crane motion induces payload oscillation that makes accurate positioning of the payload a challenging task. As the payload size increases, it may be necessary to utilize multiple cranes for better control of the payload position and orientation. However, simultaneously maneuvering multiple cranes to transport a single payload increases the complexity and danger of the operation. This thesis investigates the dynamics and control of dual-hoist bridge cranes transporting distributed payloads. Insights from this dynamic analysis were used to design input shapers that reduce payload oscillation originating from various crane motions. Also, studies were conducted to investigate the effect input shaping has on the performance of human operators using a dual-hoist bridge crane to transport distributed payloads through an obstacle course. In each study, input shaping significantly improved the task completion time. Furthermore, input-shaping control greatly decreased operator effort, as measured by the number of interface button pushes needed to complete a task. These results clearly demonstrate the benefit of input-shaping control on dual-hoist bridge cranes. In addition, a new system identification method that utilizes input shaping for determining the modal frequencies and relative amplitude contributions of individual modes was developed to aid in the dynamic analysis of dual-hoist bridge cranes, as well as other multi-mode systems. This method uses a new type of input shaper to suppress all but one mode to a low level. The shaper can also be used to bring a small-amplitude mode to light by modifying one of the vibration constraints.

Command Generation has been shown to be a practical and effective control scheme for eliminating payload swing on industrial cranes. However, this technology has not been used to its full potential. One reason is that nonlinear crane dynamics degrade the performance of current command generators, making them challenging to use. A second reason is that few crane operators are aware of this technology. Therefore, this thesis strives to alleviate these problems through the completion of three major tasks. First, new command generation algorithms are developed that compensate for nonlinear crane dynamics. Two major sources of non-linear dynamics are targeted: nonlinear drive dynamics, and non-linear physical dynamics of tower cranes. Second, command generation are examined from an educational perspective; both in the classroom and in the working field. Third, three experimental crane devices were built to fulfill the two prior tasks.

Ship-mounted cranes are used to transfer cargo from large container ships to smaller lighters when deep-water ports are not available. The wave-induced motion of the crane ship produces large pendulations of hoisted cargo and causes operations to be suspended. In this work, we show that in boom type ship-mounted cranes, it is possible to reduce these pendulations significantly by controlling the slew and luff angles of the boom. Such a control can be achieved with the heavy equipment that is already part of the crane so that retrofitting existing cranes would require a small effort. Moreover, the control is superimposed on the commands of the operator transparently. The successful control strategy is based on delayed-position feedback of the cargo motion in-plane and out-of-plane of the boom and crane tower. Its effectiveness is demonstrated with a fully nonlinear three-dimensional computer simulation and with an experiment on a 1/24 scale model of a T-ACS (The Auxiliary Crane Ship) crane mounted on a platform moving with three degrees of freedom to simulate the ship roll, pitch, and heave motions of the crane ship. The results demonstrate that the pendulations can be significantly reduced, and therefore the range of sea conditions in which cargo-transfer operations could take place can be greatly expanded. Furthermore, the control strategy is applied experimentally to a scaled model of a tower crane. The effectiveness of the controller is demonstrated for both rotary and gantry modes of operation of the crane. This work was supported by the Office of Naval Research under Contract #N00014-96-1-1123. / Ph. D.

It is sometimes necessary to transfer cargo from a large ship to a smaller ship at sea. Specially designed craneships are used for this task, however the wave-induced motions of the ship can cause large pendulations of cargo being hoisted by a ship-mounted crane. This makes cargo transfer in rough seas extremely dangerous and therefore transfer operations normally cease when sea state 3 is reached. If the cargo pendulations could be reduced in higher sea states, transfer operations would be possible. By controlling the boom luff angle, one can reduce the cargo pendulations in the plane of the boom significantly. A two-dimensional pendulum with a rigid massless cable and massive point load is used to model the system. A control law using time-delayed position feedback is developed and the system is simulated on a computer using the full nonlinear equations of motion. A three-degree-of-freedom ship-motion simulation platform, capable of simulating heave, pitch, and roll motions, was built. The computer simulation results were experimentally verified by mounting a 1/24th scale model of a T-ACS crane on the ship-motion simulation platform. / Master of Science

Rotary Cranes (Tower Cranes) are common industrial structures that are used in building construction, factories, and harbors. These cranes are usually operated manually. With the size of these cranes becoming larger and the motion expected to be faster, the process of controlling them became dicult without using automatic control methods. In general, the movement of cranes has no prescribed path. Cranes have to be run under dierent operating conditions, which makes closed-loop control preferable. In this work, two types of controllers are studied: fuzzy logic and time-delayed position feedback controllers. The fuzzy logic controller is introduced first with the idea of split-horizon; that is, to use some fuzzy engines for tracking position and others for damping load oscillations. Then the time-delayed position feedback method is applied. Finally, an attempt to combine these two controllers into a hybrid controller is introduced. Computer simulations are used to verify the performance of these controllers. An experimental setup was built on which the time-delayed position feedback controller was tested. The results showed good performance. / Master of Science

This dissertation presents new fuzzy logic techniques for designing control systems for a wide class of complex systems. The methods are developed in detail for a crane system which contains one rigid-body and one oscillation mode. The crane problem is to transfer the rigid body a given distance such that the pendulation of the oscillation mode is regulated at the final time using a single control input. The investigations include in-depth studies of the time-optimal crane control problem as an integral part of the work. The main contributions of this study are: (1) Development of rule-based systems (both fuzzy and crisp) for the design of optimal controllers. This development involves control variable parametrization, rule derivation with parameter perturbation methods, and the design of rule based controllers, which can be combined with model-based feedback control methods. (2) A thorough investigation and analysis of the solutions for time-optimal control problems of oscillation mode systems, with particular emphasis on the use of phase-plane interpretation. (3) Development of fuzzy logic control system methodology using expert rules obtained through energy reducing considerations. In addition, dual mode control is a "spin-off" design method which, although no longer time optimal, can be viewed as a near-optimal control method which may be easier to implement. In both types of design optimization of the fuzzy logic controller can be used to improve performance. / Ph. D.

Cranes occupy a crucial role within the industry. They are used throughout the world in thousands of shipping yards, construction sites, and warehouses. However, payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. Manipulation difficulty is also increased by non-intuitive crane control interfaces. Intuitiveness is characterized by ease of learning, simplicity, and predictability. This thesis addresses the issue of intuitive crane control in two parts: the design of the interface, and the design of the controller. Three novel types of crane control interface are presented. These interfaces allow an operator to drive a crane by moving his or her hand freely in space. These control interfaces are dependent on machine vision and radio-frequency-based technology. The design of the controller based on empirical means is also discussed. Various control architectures were explored. It was concluded that a controller with an input shaper within a Proportional Derivative feedback loop produced the desirable crane response. The design of this controller is complemented with a structured design methodology based on root locus analysis and computer numerical methods. The intuitive crane control systems were implemented on a 10-ton industrial bridge crane; simulation and experimental results are presented for validation purposes.

abstract: Human operators have difficulty driving cranes quickly, accurately, and safely because of the slow response of heavy crane structures, non-intuitive control interfaces, and payload oscillations. Recently, a novel hand-motion crane control system has been proposed to improve performance by coupling an intuitive control interface with an element that reduces the complex oscillatory behavior of the payload. Hand-motion control allows operators to drive a crane by simply moving a hand-held radio-frequency tag through the desired path. Real-time location sensors are used to track the movements of the tag and the tag position is used in a feedback control loop to drive the crane. An input shaper is added to eliminate dangerous payload oscillations. However, tag position measurements are corrupted by noise. It is important to understand the noise properties so that appropriate filters can be designed to mitigate the effects of noise and improve tracking accuracy. This work discusses implementing filtering techniques to address the issue of noise in the operating environment. Five different filters are used on experimentally-acquired tag trajectories to reduce noise. The filtered trajectories are then used to drive crane simulations. Filter performance is evaluated with respect to the energy usage of the crane trolley, the settling time of the crane payload oscillations, and the safety corridor of the crane trajectory. The effects of filter window lengths on these parameters are also investigated. An adaptive filtering technique, namely the Kalman filter, adapts to the noise characteristics of the workspace to minimize the tag tracking error and performs better than the other filtering techniques examined. / Dissertation/Thesis / M.S. Bioengineering 2012

In this thesis a class of robust non-linear controllers for a gantry crane system are discussed. The gantry crane has three degrees of freedom, all of which are interrelated. These are the horizontal traverse of the cart, the vertical motion of the goods (i.e. rope length) and the swing angle made by the goods during the movement of the cart. The objective is to control all three degrees of freedom. This means achieving setpoint control for the cart and the rope length and cancellation of the swing oscillations. A mathematical model of the gantry crane system is developed using Lagrangian dynamics. In this thesis it is shown that a model of the gantry crane system can be represented as two sub models which are coupled by a term which includes the rope length as a parameter. The first system will consist of the cart and swing dynamics and the other system is the hoist dynamics. The mathematical model of these two systems will be derived independent of the other system. The model that is comprised of the two sub models is verified as an accurate model of a gantry crane system and it will be used to simulate the performance of the controllers using Matlab. For completeness a fully coupled mathematical model of the gantry crane system is also developed. A detailed design of a gain scheduled sliding mode controller is presented. This will guarantee the controller's robustness in the presence of uncertainties and bounded matched disturbances. This controller is developed to achieve cart setpoint and swing control while achieving rope length setpoint control. A non gain scheduled sliding mode controller is also developed to determine if the more complex gain scheduled sliding mode controller gives any significant improvement in performance. In the implementation of both sliding mode controllers, all system states must be available. In the real-time gantry crane system used in this thesis, the cart velocity and the swing angle velocity are not directly available from the system. They will be estimated using an alpha-beta state estimator. To overcome this limitation and provide a more practical solution an optimal output feedback model following controller is designed. It is demonstrated that by expressing the system and the model for which the system is to follow in a non-minimal state space representation, LQR techniques can be used to design the controller. This produces a dynamic controller that has a proper transfer function, and negates the need for the availability of all system states. This thesis presents an alternative method of solving the LQR problem by using a generic eigenvalue solution to solve the Riccati equation and thus determine the optimal feedback gains. In this thesis it is shown that by using a combination of sliding mode and H??? control techniques, a non-linear controller is achieved which is robust in the presence of a wide variety of uncertainties and disturbances. A supervisory controller is also described in this thesis. The supervisory control is made up of a feedforward and a feedback component. It is shown that the feedforward component is the crane operator's action, and the feedback component is a sliding mode controller which compensates as the system's output deviates from the desired trajectory because of the operator's inappropriate actions or external disturbances such as wind gusts and noise. All controllers are simulated using Matlab and implemented in real-time on a scale model of the gantry crane system using the program RTShell. The real-time results are compared against simulated results to determine the controller's performance in a real-time environment.

Heavy-lifting machines such as cranes are widely used at ports, construction sites, and manufacturing plants in a variety of material-transporting applications. However, cranes possess inherent flexible dynamics that make fast and precise operation challenging. Most cranes are driven by human operators, which adds another element of complexity. The goal of this thesis is to develop controllers that allow human operators to easily and efficiently control machines with flexible dynamics. To improve the ease of human operation of these machines, various control structures are developed and their effectiveness in aiding the operator are evaluated. Cranes are commonly used to swing wrecking balls that demolish unwanted structures. To aid the operator in such tasks, swing-amplifying controllers are designed and their performance are evaluated through simulations and experiments with real operators. To make maneuvering of these machines in material-transporting operations easier, input-shaping control is used to reduce oscillation induced by operator commands. In the presence of external disturbances, input shaping is combined with a low-authority feedback controller to eliminate unwanted oscillations, while maintaining the human operator as the primary controller of the machine. The performance and robustness of the proposed controllers are thoroughly examined via numerical simulations and a series of experiments and operator studies on a small-scale mobile boom crane and a two-ton dual-hoist bridge crane.