Hunting reduction and travelling stabilization at high speed are required to improve the travelling characteristics of an unmanned delivery cart (AGV : Automatic Guided Vehicle), which is a component of modern FA system. In this paper, the travelling behavior model of an AGV is developped considering the inertia force and cornering force of the wheels. Factors which affect on steering characteristics are examined through simulation with the developped model and experiments. Steering control scheme is considered via examining limit velocity for stable travelling and control system stability. Finally, required factors for an AGV to travel on a straight line at high speed are high accuracy detectors, high response steering system, and optimal steering gain. In the experiment of the developped AGV with the forementioned control scheme, it was verified that the AGV can travel smoothly at 60 m/min with as little as ±16 mm amplitude and 3 sec. period hunting motion, which is less than the guiding tape width.
In this paper, we apply the simulated annealing algorithm to the flow shop scheduling problem with an objective of minimizing the makespan and show its power as an approximate algorithm by the numerical experiment on randomly generated test problems. In the numerical experiment, we compare the simulated annealing algorithm with the other approximate algorithms including the RAES algorithm proposed by Dannenbring, its slightly modified algorithm, a random search algorithm and a local search algorithm. We also show that the performance of the simulated annealing algorithm depends on the choice of a neighborhood structure.
New overlapping coordination method by nonfeasible decomposition has recently been developed. In this paper, we will further extend the ideas introduced there and propose new coordination procedure which has 2 level structures. In this proposed method, the upper level sends the values of Kuhn-Tucker (or Lagrange) multipliers of the common coupling constraints of different decompositions to the lower level. In the lower level, different overlapped decompositions solve the problem by exchanging the values of Kuhn-Tucker (or Lagrange) multipliers of constraints with each other which are coupling only in each decomposition. The lower level sends the obtained solution back to the upper level. The upper level modifies the values of multipliers and sends them to the lower level, again. This procedure is repeated until the convergence is achieved. The proposed method seems very promising and attractive for the future application research of overlapping coordination.
This paper discusses the influence of spatial characteristics of objects on a surface following control system equipped with an ultrasonic orientation sensor, and proposes a method to evaluate the performances of the control system by spatial frequency response. The sensor measures the orientation by the phase difference of reflected echoes and is applied to the control system to maintain the hand orientation perpendicular to the objective surface. The measuring algorithm of the sensor is based on the mirror property of sound reflection from a plate with an infinite area. However, actual object for surface following task has uneven surface. The unevenness causes significant errors on the measured orientation. Consequently, the control system using the sensor is also influenced by surface characteristics of the objects. The characteristics are expressed by spatial frequency response. The method using the frequency response is very usefull for evaluation of the performances of the control system, such as the ability to follow the curved surface and the ability to reduce the influence of small irregularities on the surface.