Tracking controls for the speed and azimuth of a mobile robot driven by two independent drive wheels are experimentally attained by using a computed torque control and a fuzzy control. The computed torque controller can be easily derived by using the physical parameters for the mobile robot. However, the computed torque controller for the speed of the mobile robot can have only the P-servo controller. In order to improve the performance of such a controller, we introduce a computed torque controller having the D-servo compensator with respect to the speed error. A fuzzy controller is also applied to the present problem, in which the conclusion consists of a function of mean-values on each membership function in the antecedent. The effectiveness of two control methods is illustrated by some experiments and compared with the conventional PID control method.
There are many research approaches to develop intelligent robot. However most of them could not be applied to real tasks. We think it is important to develop a new hardware design concept which includes moduled robot elements and system interfacing flexibility through verious robot developments. Through this concept moduled robot elements which have new open interfaces to be useful for many kind of users were developed. These elements have hierarchical 5 level hardware modules; Mechanism, Servo, I/O, Network, Computer interface. By using this result, we could develop some robot systems, e. g. 7-Axis Manipulator, Under Water Maintenance Robot with Double Arms and Oil-Tank Bottom-Plate Blast Robot, and require some evidences in order to develop robots rapidly. We think our Open System causes many Intelligent Robots to be applied. Because most of intelligent robot researcher can work in own field without robot hardware developments which require much research part.
A security camera system in this article means such a system as observes movement of a man with a video camera and that gives a warning if the movement is suspicious. By using a method of self-organizing a binary tree, this article constructs an associative memory system that accepts, as inputs, dynamic patterns including a time axis. This article also studies on a possibility of realizing automatic customization of the security camera system based on this associative memory system. An experimental evaluation on computation times is shown.
The purpose of this work is to develop a wheeled inverse pendulum type mobile robot which can autonomously navigate in a two dimensional plane while keeping its own balance. In this paper, we report the construction and control algorithm of the wheeled inverse pendulum type self-contained mobile robot “Yamabico Kurara”. Yamabico Kurara has a functionally distributed architecture. The navigation program is located in the behavior control level and is implemented on the master module which takes the part of total control. Posture and trajectory tracking control are realized on the locomotion module which is one of the functional modules at the system level. The results of locomotion control experiments and navigation in the indoor environment of the robot are also shown. Discussion on the system integration and feasibility of the application is also included.
A new driving mechanism for holonomic omni-directional mobile robots is designed, which enables 3 DoF (degrees of freedom) motion control in two dimensional space by three correspondent actuators in a decoupled manner without redundancy. The kinematics of the omni-directional mobile robot is also analyzed to prove that driving motion by the actuators is decoupled by the developed mechanism into 3 DoF motion of the robot. A prototype of the omni-directional mobile robot with the driving mechanism is developed including a parallel link suspension mechanism. Finally, the performance of the prototype robot is shown through experimental results, by which the working of the designed mechanism is verified.
This paper describes a control method for manipulators which work by pressing the end-effector to the workpiece under constant force (e.g. grinding and cleaning) and also positioning the end-tip to everywhere on the workpiece using the operation device. Based on ergonomics, “the operator coordinate system” is introduced which is determined from the glance line to the workpiece and the both eyes of the operator. Further, “the corresponding-to-operational-motion type control method” is proposed, on which method the direction of motion of the operation device and the reactive direction of motion of the end-effector are corresponded in the operator coordinate system. Especially for the workpiece with wave shape, “the corresponding-to-objective-shape type control method” is designed, on which method the winding line and the valley line of the wave are recognized during the work and the directions of motion of the operation device are corresponded to these lines. These methods have been applied to the remote control system including the joystick and the lightweight manipulator, so the efficiency of these methods have been confirmed.
A coordinated control method for two mobile robots without explicit communication is presented in this paper. Concretely, transferring control by cooperation of two robots is realized from the viewpoints of mechanical design and of control system design. In the mechanical design, compliance mechanism with 3 degrees of freedom is added on one of the robots in order to avoid extreme inner forces between the robots. In the control system design, leader-follower method is adopted. “Virtual Impedance Method” is used for controlling the follower robot. A deadlock problem, where a robot stops at some other positions from a target position of the robot, is solved by transforming lateral virtual forces to virtual moments. Effectiveness of the proposed method is verified by experimental results. The proposed method is applicable to multiple mobile robot system by increasing the number of followers.
In this paper we describe a new coupled tendon-driven joint mechanism that uses pneumatic bellows actuators. With regard to the mechanism, frames are attached to shafts of the bellows actuators and are connected to one link arm with wire. By making pressure difference between one side chamber of the actuator and the other, the joint revolves. From experimental results we disclose the static and dynamic characteristics of the proposed mechanism. Moreover, it is demonstrated that good positioning performance is realized by using a hierarchical control scheme which was proposed to control pneumatic drive systems. Since the bellows system has force-sensing ability, the proposed mechanism can estimate external forces without additional force sensors. In practice, we confirm the forcesensing ability through some experimental results.
This paper presents an efficient algorithm for multibody systems with closed loops. In most simulators for analysis of mechanical systems, a dynamic model is made by constraint equations in Cartesian coordinates. However in this way, such modeling requires many variables and long CPU time. As a solution of this problem, we have developed an efficient recursive formulation of dynamics of multibody systems by relative coordinates and partial velocity. The simulation systems based on this algorithm proceeds computation as follows: Firstly, Graph theory is applied to characterize the topology of mechanical systems and cut some joints to open the closed chain systems. Secondly, the computational sequences for formulation is defined along the branches. Finally, an order n(O(n)) algorithm is introduced to reduce the number of arithmetic operation. This algorithm shows that it can successfully solve the equation of motion much faster than Cartesian coordinates formulation.
In this paper, we show a validity of a new programming paradigm called constraint logic programming by constructing a robot structure design support system. The design process of a robot structure is divided into a fundamental structure design and a internal structure design. A fundamental structure design is a process that determines a framework of the robot such as a degree of freedom, a number of joint etc. We mainly support a fundamental structure design. This design system is constructed by constraint logic programming language. The buchberger algorithm is used to calculate the non linear equation in this language. Our design system generates an analysis program independent of robot structure easily. The result of analysis is also gotten in the form of expression. The constraint can be appended incrementaly. By constructing such a system we can achieve remarkable reduction of desiner's work in design process.
A 6-DOF parallel robot called HEXA which we have developed recently is suited for very fast motion. In this paper, we apply dynamic control to the HEXA robot to improve the accuracy of its trajectory tracking in the fast motion. First, we present a simple dynamic model for the HEXA robot to decrease the cost of computation and, then, experiment on identification of its parameters. We adopt so-called Adept motion, which is commonly used as a benchmark to measure the ability of fast motion, to evaluate the effect of the dynamic control. The results of the experiment on the dynamic control show that the control improves the trajectory tracking accuracy dramatically.
This paper presents a learning architecture with an evolutionary learning algorithm of collective behaviors for a group of mobile robots. The base learning algorithm is a distributable genetic algorithm with a redundant coding (RGA). The application of standard GA to distributed robot systems faces three drawbacks that (1) GAs do not consider non-stationary environments, (2) GAs are centralized algorithms, and (3) GAs require the synchronization for generation replacements. The proposed architecture enables GA to search a wide range of solutions by augmenting the diversity of genetic information so that the optimum solutions varying over time can be followed by GA. The analytic results about the reason why RGA outperformes standard GA in non-stationary environments are presented. RGA is converted into a distributed and asynchronous evolutionary algorithm (DRGA). The simulation results of a problem to learn collective strategies to capture fleeing targets verify the validity of the proposed algorithm and the learned strategies are shown to be reasonable ones.
This paper describes an adaptive visual servoing controller consisting of an on-line estimator and a feedback/feedforward controller for uncalibrated camera-manipulator systems. The estimator does not need a priori knowledge on the kinematic structure nor parameters of the camera-manipulator system, such as camera and link parameters. The controller consists of feedforward and feedback terms to make the image features converge to the desired trajectories, by using the estimated results. Some experimental results demonstrate the validity of the proposed estimator and controller.