Creation of advanced dexterous mechanical manipulators and actuators is increasingly important for development of intelligent robots, which are capable of performing any human arm task. This Paper deals with an application of an ultrasonic motor to such a dexterous actuator which has multi-degree of freedom. In the view of the principle of drive which produces torque by the act of friction, ultrasonic motor can be easily applied to obtain the desired motion. Multi-degree of freedom motion can be obtained by using a spherical shaped rotor and stators. Presented in this paper are the development of the stator for a spherical rotor, simulation of vibration mode of stator and experiments to determine the optimal design and control parameters (contact force between the rotor and the stator, driving voltage and thickness of lining material) which have effects on the performance of the actuator.
In order to obtain the information of the environment for the robot to work, it may be the effective way to work on the environment through the robot's action. In accordance with this idea, a method dealing with the automatic three-dimension partitioning of overlapped objects has been proposed by using the robot vision system which was proposed and constructed by authors. As compared with other researches about partitioning until now, our method can obtain the three-dimension partitioning planes among unknown overlapped objects and this makes it possible to generate the each geometric model of those objects. Within this method, some active techniques such as using laser spotter scanning to obtain the appropriate visual points for investigating the partitioning condition of overlapped objects have been developed. This technique has been proved to be effective to obtain the threedimension partitioning plane of those overlapped objects. Experiments dealing with the several cases of overlapped objects' partitioning make clear the validity of this method. And with these obtained 3-D partitioning plane, the each geometric model of the overlapped objects has been generated automatically.
The perspective control for Articulated Body Mobile Robot KORYU is discussed. Being constructed by linearly connected articulations, the segments of the KORYU except that of foremost one can predict future posture by the information of adjacent frontal segment whilel ocomotion. The paper introduces the method to make exact prediction of future posture for any segment of KORYU by using Maximum Principle and the method is then developed to be used for the locomotion on arbitrary topology of the uneven ground. The validity is verified by experiment using the mechanical model “KR-I”.
This paper proposes the fast motion control of robot manipulator based on the new acceleration controller. This acceleration controller constructed by using mixed sensitivity problem of H∞ control. The proposed acceleration controller discusses the frequency performance taking sensor noise effect and disturbance rejection into account systematically. This acceleration controller is simple and robust. Moreover, this paper proposes the new fast motion controller based on H∞ acceleration controller. This new fast motion controller is realized by using only information of position, and it makes the multi-degrees-of-freedom motion control system more simple. In this paper, the proposed controller is constructed by the software algorithm of DSP. The experimental results show that the proposed control is valid for motion control of three-degrees-of-freedom robot manipulator.
The new unified displacement analysis of arbitrary kinds of mechanisms has been developed. When inputs of a mechanism are fixed, a mechanism can be dissolved into a series of irreducible structures. It is proposed that the displacement analysis becomes simpler by analyzing these irreducible structures successively. For the displacement analysis of structures, the compliant kinematic pair model is defined in which forces proportional to the deviations from the theoretical locations between kinematic pair elements act on each link. The displacement analysis can be performed by searching equilibrium locations of links of a structure with compliant kinematic pairs.
A tendon-controlled mechanism has more actuators than its degrees of freedom. The redundancy enables us to reduce mechanical backlash, avoid near zero tendon forces, where the control accuracy goes down, and adjust the mechanical compliance at the expense of some cancellationn of torques. Thus the tendon-controlled mechanism could be more flexible and adaptable to complicated tasks in a unconstructed environment. This paper describes a tendon-controlled 3 DOF wrist mechanism with four tendons. First a relationship between a joint space and a tendon space is derived. Then, the joint accessible space, where any joint torque is generated by tensile tendon forces only, and the manipulability of the wrist are analyzed. Tendon forces for desired joint torques are determined by a linear optimization problem solution. Funally simulations and experiments are given to show the efficiency of the compliance control of the tendon controlled wrist mechanism.
Task motion with task coordinates is described by the component feature labels given to six degrees of freedom. A task motion model is proposed as a CF model. The CF model representation includes not only natural and artificial constraints but also sensor-based tracking motion control. A number of task motions to be analyzed are collected and described by the CF model. Assisted design support based on constraints satisfaction is also shown to be achieved by the CF model task representation.
The authors have been using the ZMP (Zero Moment Point) as a criterion to distinguish the stability of walking for a biped walking robot. If the ZMP during robot walking can be measured, it is possible for a biped robot to realize stabler walking by a control method that makes use of the measured ZMP. In this paper, a method that measures the ZMP throughout the whole walking phase is proposed. A ZMP measurement system using two universal force-moment sensors is developed and installed into a biped walking robot. The accuracy of the ZMP measurement system is experimentally confirmed, and the ZMP throughout the whole walking phase is measured.
A remote operating system is required to control reliably and effectively, and to be used easily. As the remote operating system with legs, arms, hands, eyes and ears correspond to the human's ones is increasing the operation task, it is hard for only one human operator to control the operating tasks reliability and effectively. And so we consider it necessary the new method to operate with sensuous operation using the operator's knowledge and experience, and in this method, to control the slave-manipulator and ITV camera as if he felt with his own arms, hands, eyes and ears. In this paper, to develop the new method, we have made the experiments of ITV camara control test using joy stick lever, the voice command, operator's eyes and neck motion, and discriminating the direction of sound source test using ITV camera with the microphone. As the results, in the former test, it becomes clear that the voice command control mode and operater's neck control mode are able to be used instead of joy stick control mode, and we have extracted the factors of evaluating the operability. In the latter test, that is the dummy head that can be turned with the microphones is able to be used for discriminating the direction of sound source in the field, also is able to get the existence in the field.