In this paper, first, the equation of motion of a horizontal two-link flexible robot arm is derived. The flexible robot arm consists of first rigid link, second flexible link and a control system, and the restriction force is applied to the end of the flexible robot arm. Then, the design method of the control system with PIS control (proportional plus integral control of the strain of the flexible link) is showed, and the experimental results are demonstrated. From the experimental results, it is seen that the control performance of the present position and force control system by use of PIS control is excellent. Furthermore, the dynamic numerical simulation results of the system are demonstrated.
Tender subjects for the autonomous mobile robots are an accurate measurement of their locations. The dead reckoning method using a distance counter with wheel and a ratio gyro is generally used for them. This method is attended with the accumulation of the accidental error. This paper proposes a new measurement system of location using an optical servo system which follows a lighthouse all the time. For the luminous source of the lighthouse the infrared rays are used because they are harmless and safe for human beings. The experimental results demonstrate the effectiveness of the optical servo system for the autonomous robots.
In order to achieve a fast and powerful motion of a robot, the development of an actuator with high output energy/weight ratio is indispensable. Output energy/weight ratio of piezoelectric motor is higher than that of magnetic motor. So, piezoelectric motors have a possibility to realize the actuator with high output energy/weight ratio. But its driving mechanism is not perfectly clarified. In this report, we proposed a dynamic modeling method for the stator of an inclined-type piezoelectric motor which we had developed before. This model describes the mechanical characteristics (vibration mode, amount of heat) and electric characteristics (electric impedance) of the motor well and the validity of this modeling method was confirmed by experiment.
For an intelligent robot, determining efficiently the data of shape and posture of the objects in the real world environment will increase greatly the adaptation capacity for the unknown environment. With respect to these unknown 3-D objects, a robot vision system is proposed which is capable of constructing automatically their geometric models which include the information of both the shape and the posture or position of the objects. By means of this system, a “Visual Points Selecting Cone Intersection Method” is proposed which can select appropriate camera viewing point and direction automatically as investigating the partial shape of the object. With this method, experiments was performed which make clear that this method can get the model of object more accurately and effectively.
In this paper, a quasi-static object manipulation by an articulated three-fingered robot hand with slip motion of grasping is discussed. This kind of manipulation achieves more dexterous manipulation by robot hands. The equilibrium relations of fingertip forces for grasping an object are solved in three dimensions. It is assumed that a slip happens when the fingertip forces go beyond the bound of the cone of maximum static friction. Possible directions of slip within a grasp are determined from the analysis. The fingertip force which achieves a desired slip motion is determined uniquely. Finally the set of fingertip forces is obtained, and the planning method of slip motion is dicussed.
This paper describes a new design of a fluid driven micro-actuator which can be fabricated by anisotropic etching of single crystalline silicon. The actuator has a four-way valve to regulate the work fluid and a differential piston to generate linear force. First, fundamental flow characteristics are analyzed theoretically when the fluid flows in simple channels which have rectangular and trapezoidal cross section. Applicability of the Navier-Stokes equation assumed in the analysis is confirmed about the specific dimensions used in the actuator design by actual flow measurement. Then proposed actuator is examined separately on four constituent parts by numerical resolution of the N. S. equation. Consequently the results are integrated to estimate the output of the actuator. The design parameters of piston-casing clearance, piston width and casing height are investigated to evaluate the effect on the output. Finally the output characteristics are compared with that of an electrostatic actuator. The output and the one for unit area are expected to be a hundred times and ten times as large as those of the electrostatic actuator respectively.
An important subject for a mechanical engineer is the development of autonomous mobile robots which have the ability to work in environments hazardous to human beings. Integrated control systems with microprocessors and various kinds of sensors can contribute to this subject. There are, however, many kinds of problems in the development of the intelligent working robots. This paper discusses the problems of navigation in flat enclosed areas and proposes the schemes to cover the entire area. The utility of the scheme is demonstrated by using a developed three-wheel robot with supersonic sensors for external sensing.
This paper presents a tele-existence master-slave manipulation system. We have proposed the impedance controlled type MSMS. The system has the arm and environment models as mechanical impedance, and gives a sophisticated operational reality with some modification of the models. In the paper, the MSMS is generalized for the system robustness and its ideal bilateral teleoperation response.