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The use of gantry crane systems for transporting payload is very common in industrial application. However, moving the payload using the crane is not an easy task especially when strict specifications on the swing angle and on the transfer time need to be satisfied. To overcome this problem, an intelligent gantry crane system had been introduced. Fuzzy logic controllers were adopted, designed and implemented for controlling payload position as well as the swing angle of the gantry crane. In this paper, robustness of the proposed intelligent gantry crane system is evaluated and compared with an automatic gantry crane controlled by the classical PID controllers. The result shows that the intelligent gantry crane system is more robust to parameter variation than the automatic gantry crane system.

The use of gantry crane systems for transporting payload is very common in building constructions. However, moving the payload using the crane is not an easy task especially when strict specifications on the swing angle and on the transfer time need to be satisfied. Various attempts in controlling gantry cranes system based on open- loop and closed-loop control systems were proposed. However, most of the proposed controllers were designed based on the model and parameter of the crane system. In general, modeling and parameter identifications are troublesome and time consuming task. To overcome this problem, in this paper, a practical and intelligent control method for automatic gantry crane is introduced and evaluated experimentally. The results show that the proposed method is not only effective for controlling the crane but also robust to parameter variation.

SUMMARYThis paper establishes a novel approach of robotic hand posture and grasping control. For this purpose, the control uses the operational space approach. This permits the consideration of the shape of the object to be grasped. Thus, the control is split into a task control and a particular optimizing posture control. The task controller employs Cylindrical and Spherical coordinate systems due to their simplicity and geometric suitability. This is achieved by using an integral sliding mode controller (ISMC) as task controller. The ISMC allows us to introduce a model reference approach where a virtual mass-spring-damper system can be used to design a compliant trajectory tracking controller. The optimizing posture controller together with the task controller creates a simple approach to obtain pre-grasping/object approach hand postures. The experimental results show that target trajectories can be easily followed by the task control despite the presence of friction and stiction. When the object is grasped, the compliant control will automatically adjust to a specific compliance level due to an augmented compliance parameter adjustment algorithm. Once a specific compliance model has been achieved, the fixed compliance controller can be tested for a specific object grasp scenario. The experimental results prove that the Bristol Elumotion robot hand (BERUL) can automatically and successfully attain different compliance levels for a particular object via the ISMC.

This paper establishes a novel approach of robust active compliance control for a robot hand via an Integral Sliding Mode Controller (ISMC). The ISMC allows us to introduce a model reference approach where a virtual mass-spring damper system can be used to design a compliant control. In order to allow for practical grasping, we consider the shape of the object to be grasped. Hence, the work exploits a grasping technique via Cylindrical and Spherical coordinate systems due to their simplicity and geometric suitability. The control uses the operational space approach. Thus, the control is split into a task control and a particular optimizing posture control. The experimental results show that target trajectories can be easily followed by the task control despite the presence of friction and stiction while the posture controller maintains a desired finger posture. When the object is grasped, the compliant control will automatically adjust to a specific compliance level. Once a specific compliance model has been achieved, the fixed compliance controller can be tested for a specific scenario. The experimental results prove that the BERUL hand can automatically and successfully attain different compliancy levels for a particular object via the ISMC.