A cable-suspended intelligent crane assist device for the intuitive manipulation of large payloads

This paper presents a cable-suspended crane system to assist operators in moving and lifting large payloads. The main objective of this work is to develop a simple and reliable system to help operators in industry to be more productive while preventing injuries. The system is based on the development of a precise and reliable cable angle sensor and a complete dynamic model of the system. Adaptive horizontal and vertical controllers designed for direct physical human-robot interaction are then proposed. Different techniques are then proposed to estimate the payload acceleration in order to increase the controller performances. Finally, experiments performed on a full-scale industrial system are presented

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

Payload's sway angle measurement for container in the crane system based on remote sensing

The demand for a high quickly measuring angle in the port crane system should be considered when the container has been transferred from one place to another place. It is significant to build the feedback linking of payload's angle in the integrated crane system. The value of accurate measurement of the angle can be used to optimize the crane control system. In this context, the design and implementation of the experimental setup associated with emulated cranes will be carried out. Several solutions for remote angle measurement were considered one of the considered solutions being represented by millimeter microwave radar sensors. Special developments of algorithms to calculate the sway angle of payload or container were considered as so as the real-time processing using Arduino Uno computation platform. The following objectives were successfully reached. 1. Development of remote sensing system for payload's swing angle measurement considering radars such the sensing devices; 2. Development of a novel angle algorithm measurement and real-time processing of data; 3. Development of a prototype characterized by real-time processing and remote detection capabilities considering short-range and long-range measurements, such as lidar sensor or radar sensor.A demanda por um ângulo de medição rápido e alto no sistema de guindaste portuário deve ser considerada quando o contêiner for transferido de um local para outro. É significativo construir a ligação de feedback do ângulo da carga útil no sistema de guindaste integrado. O valor da medição precisa do ângulo pode ser usado para otimizar o sistema de controle do guindaste. Neste contexto, será realizada a concepção e implementação da configuração experimental associada a gruas emuladas. Diversas soluções para medição remota de ângulos foram consideradas uma das soluções consideradas sendo representadas por sensores de micro-ondas milimetrados. Desenvolvimentos especiais de algoritmos para calcular o ângulo de oscilação da carga útil ou contêiner foram considerados, assim como o processamento em tempo real usando a plataforma de computação Arduino Uno. Os seguintes objetivos foram alcançados com sucesso. 1. Desenvolvimento de sistema de sensoriamento remoto para medição do ângulo de oscilação da carga útil considerando radares como os dispositivos de detecção; 2. Desenvolvimento de um novo algoritmo de medição de ângulos e processamento de dados em tempo real; 3. Desenvolvimento de um protótipo caracterizado por processamento em tempo real e capacidade de detecção remota considerando medições de curto e longo alcance, como sensor LIDAR ou sensor de radar

Improving cable driven parallel robot accuracy through angular position sensors

Conventionally, a cable driven parallel mechanism (CDPM) pose is obtained through the forward kinematics from measurements of the cable lengths. However, this estimation method can be limiting for some applications requiring more precision. This paper proposes to use cable angle position sensors in addition to cable length measurements in order to improve the accuracy of such mechanisms. The robot pose is first obtained individually by the cable length measurements and the cable angle position measurements. A data fusion scheme combining these two types of measurements is then proposed in order to improve the CPDM accuracy. Finally, simulations and experiments are presented in order to assess the benefits of using cable angle position sensors on the CDPM

Upgrading for overhead crane anti-sway method using variable frequency drive

The paper discusses about upgrading the overhead crane anti-sway method base on the induction motor torque control from rotor resistance starter to variable frequency drives (VFDs). The upgrading included two phases. The phase 1 is to identify the performance of the overhead crane operation on anti-sway method base on the induction motor torque control using rotor resistance starter (old existing motor starter). The phase 2 is to identify the performance of the overhead crane operation on anti-sway method base on the induction motor torque control that use a variable of frequency drive (new upgrading motor starter). The primary equations connecting tractive force and load sway angle, which the motor torque control law is based on is designed for 0% load wobble at the end of the journey. The words accelerating and braking have been written. Outcomes of modelling the behaviour of a trolley-load of two masses for the normal overhead crane load ratios, a system is described weight to the length of the rope, which supports the hypothesis concerning the feasibility of direct load anti-sway control ON and OFF for regulation of motor for overhead cranes

Trailer Sway Control Using an Active Hitch

The handling and yaw stability characteristics of passenger vehicles are drastically changed when towing a trailer, which can lead to unsafe oscillations in the trailer yaw, known as trailer sway. This thesis examines the feasibility of using lateral articulation of the hitch ball to reduce sway behavior in passenger-sized tractor-trailer configurations. An articulating hitch ball design has the advantage of not being dependent on the trailer being towed, providing stability improvements to the wide variety of trailers that a passenger vehicle may tow over its life cycle. Changes in the lateral position of the hitch relative to the tractor create dynamic changes to the heading angle of the trailer relative to the tractor, which act as compensating steering inputs into the system. To examine the effectiveness of this method, a linear handling model was developed to predict the system response with different trailer configurations and feedback methods. This model was simulated with various feedback controllers, and the modeling was validated using a model constructed in MapleSim, a high-fidelity multibody simulation tool. After establishing the required performance characteristics of the active hitch, a prototype was designed, manufactured, and tested in a full scale tractor-trailer combination. The modeling techniques showed good agreement with the physical testing, where the control design of proportional feedback on the trailer articulation angle provided improved yaw stability across many trailer configurations. The simple controller design is adaptable to driving conditions and requires minimal measurements of vehicle states. The performance of the active hitch prototype is best shown in a response to a steering impulse at 65km/h, where a highly unstable trailer causes steady state oscillation without control, and settles in under 4 seconds with control active

Trailer Sway Control Using an Active Hitch

The handling and yaw stability characteristics of passenger vehicles are drastically changed when towing a trailer, which can lead to unsafe oscillations in the trailer yaw, known as trailer sway. This thesis examines the feasibility of using lateral articulation of the hitch ball to reduce sway behavior in passenger-sized tractor-trailer configurations. An articulating hitch ball design has the advantage of not being dependent on the trailer being towed, providing stability improvements to the wide variety of trailers that a passenger vehicle may tow over its life cycle. Changes in the lateral position of the hitch relative to the tractor create dynamic changes to the heading angle of the trailer relative to the tractor, which act as compensating steering inputs into the system. To examine the effectiveness of this method, a linear handling model was developed to predict the system response with different trailer configurations and feedback methods. This model was simulated with various feedback controllers, and the modeling was validated using a model constructed in MapleSim, a high-fidelity multibody simulation tool. After establishing the required performance characteristics of the active hitch, a prototype was designed, manufactured, and tested in a full scale tractor-trailer combination. The modeling techniques showed good agreement with the physical testing, where the control design of proportional feedback on the trailer articulation angle provided improved yaw stability across many trailer configurations. The simple controller design is adaptable to driving conditions and requires minimal measurements of vehicle states. The performance of the active hitch prototype is best shown in a response to a steering impulse at 65km/h, where a highly unstable trailer causes steady state oscillation without control, and settles in under 4 seconds with control active

Motion cueing in driving simulators for research applications

This research investigated the perception of self-motion in driving simulation, focussing on the dynamic cues produced by a motion platform. The study was undertaken in three stages, evaluating various motion cueing techniques based on both subjective ratings of realism and objective measures of driver performance. Using a Just Noticeable Difference methodology, Stage 1 determined the maximum perceptible motion scaling for platform movement in both translation and tilt. Motion cues scaled by 90% or more could not be perceptibly differentiated from unscaled motion. This result was used in Stage 2‟s examination of the most appropriate point in space at which the platform translations and rotations should be centred (Motion Reference Point, MRP). Participants undertook two tracking tasks requiring both longitudinal (braking) and lateral (steering) vehicle control. Whilst drivers appeared unable to perceive a change in MRP from head level to a point 1.1m lower, the higher position (closer to the vestibular organs) did result in marginally smoother braking, corresponding to the given requirements of the longitudinal driving task. Stage 3 explored the perceptual trade-off between the specific force error and tilt rate error generated by the platform. Three independent experimental factors were manipulated: motion scale-factor, platform tilt rate and additional platform displacement afforded by a XY-table. For the longitudinal task, slow tilt that remained sub-threshold was perceived as the most realistic, especially when supplemented by the extra surge of the XY-table. However, braking task performance was superior when a more rapid tilt was experienced. For the lateral task, perceived realism was enhanced when motion cues were scaled by 50%, particularly with added XY-sway. This preference was also supported by improvements in task accuracy. Participants ratings were unmoved by changing tilt rate, although rapid tilt did result in more precise lane control. Several interactions were also observed, most notably between platform tilt rate and XY-table availability. When the XY-table was operational, driving task performance varied little between sub-threshold and more rapid tilt. However, while the XY-table was inactive, both driving tasks were better achieved in conditions of high tilt rate. An interpretation of these results suggests that without the benefit of significant extra translational capability, priority should be given to the minimisation of specific force error through motion cues presented at a perceptibly high tilt rate. However, XY-table availability affords the simulator engineer the luxury of attaining a slower tilt that provides both accurate driving task performance and accomplishes maximum perceived realism

NASA/ASEE Summer Faculty Fellowship Program, 1990, Volume 1

The 1990 Johnson Space Center (JSC) NASA/American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program was conducted by the University of Houston-University Park and JSC. A compilation of the final reports on the research projects are presented. The topics covered include: the Space Station; the Space Shuttle; exobiology; cell biology; culture techniques; control systems design; laser induced fluorescence; spacecraft reliability analysis; reduced gravity; biotechnology; microgravity applications; regenerative life support systems; imaging techniques; cardiovascular system; physiological effects; extravehicular mobility units; mathematical models; bioreactors; computerized simulation; microgravity simulation; and dynamic structural analysis

Underwater Vehicles

For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties