We have developed an artificial finger which has a human tactile sensibility function, and is desired for some kinds of robots. This finger can recognizes some materials by only the actions of pressing and tracing an object actuated by the pneumatic cylinder. In general, there are many factors in recognizing the material, that is, “Surface condition”, “Hardness” and “Temperature” and they are used as input factors in the neural network in the study. This study also borrows from the action potential of humans. The action potential fires some impulses when a stimulus is applied to the skin. The human brain handles the impulse as input data. The advantage of inducing the impulse model in the artificial finger is to reduce the volume of calculation, and to handle the data of some sensors in parallel. Furthermore, we provided an artificial finger that has a finger joint. The pneumatic cylinder and the tendon actuate the joint to bend the finger. The purpose of making the finger joint is to improve the sensitivity for parameters and the effects are certified in this report.
At the close of the 20th century, in Japan, the reduction of incidence of the care worker in an aging society is becoming pressing need. Then, we aim at the development of the robot arm for care which is flexible and united with the motion of man.In this subject, we suggest to develop the “Tendon-Driven 2-Link Manipulator Driven by Pneumatic Cylinder” as the care lift for assisting the rising and sitting of elderly people, disabled people or wheelchair users.The tendon-driven manipulator system developed in this subject makes use of the pneumatic cylinder as an actuator. A pneumatic actuator is characterized by enabling the flexible action by the compressibility of the air. By means of the fl exible action caused by the compressibility of the air, the welfare system making use of a pneumatic actuator can be expected to the “Human-Friendly Assist”.
It seems to be useful to apply the model reference adaptive control (MRAC) method for pneumatic servo systems. Since pneumatic servo systems are easily effected by the change in system parameters such as the load mass or supply pressure, etc.The MRAC method for the pneumatic cylinder position servo system using a diaphragm-type electro-pneumatic converter is proposed in this paper. The converter acts with a very short lag time and has a simple first order transfer function. So the total transfer function of the servo system can be represented to the lower order system and this is suitable for the execution of MRAC.The experimental tests were carried out by using a 200-mm stroke and 40-mm bore single rod-type air cylinder. The reference model was set to the second order system which has an optimal dumping factor. Also, the response of the MRAC was tested under the various input conditions such as a rectangular signal, sinusoidal signal or triangular signal was yielded, respectively.As a result, the accommodations for the change in load mass, supply pressure or magnification of servo amplifier could be clarified.
The pneumatic cylinder has internal rubber seals. When the piston moves toward the desired position, the seal sticks and slides and then attaches itself to the cylinder wall or piston rod, near the final position. Therefore the viscoelastic formation of the seal occurs, witch has effects on control performances, such as positioning accuracy, stability and settling delay in this region. Combination of stick and slide mode control models is necessary to execute highly stable and accurate control of a pneumatic cylinder, but these modes can not be observed directly.In this report, a method is proposed for discriminating whether the seal sticks or slides in real time and for its control by choosing and switching between slide or stick modes. The control performance is specified experimentally.
Intending to explore the possibility of the optical control robot without interposing any electrical signal, pneumatic control robot arm controlled with photofluidic interface was developed.The interface employs a light absorbing nozzle wall in a laminar proportional fluid amplifier. The fluidic output signal of the interface was amplified by a three-stage laminar proportional amplifier gain block. Robot arm has two members and two joints moved by pneumatic rotary actuators. A membrane type booster amplifier with three staged nozzle-flapper values was used to amplify the power of the output signal of the gain block so far as enough to drive the rotary actuators. Two control methods, such as proportional control employing integration compensation and model reference adaptive control were applied and the comparison of the suitability of these control methods was made.
