Abstract
Acceleration control using detected external force, is a scheme to control a manipulator to carry an object with the acceleration proportional to the external force. A special type manipulator named suspend-type manipulator was designed for the controlled manipulator.
Suspend-type manipulator is a paralled type manipulator that hangs an object with wires and controls its motion by driving those wires. It has an ability same as the transfer machines such as cranes and can control the position of the object more exactly.
Adaptive control to the external force is useful for aiding the manual transfer operation. Most control systms or mechanisms that have developed to generate the adaptive motion to the external force, are too much dedicated to some task or hardware mechanism, even if some of them are widely used in industries. They do not respond to various situations and requirements.
We have developed a control system responding to the external force as follows. First, we decompose the whole control system into three parts; a part to detect the external force, a part to generate desired motion, and a part to make the manipulator follow the desired motion. With this configuration, we can make the control indepedent from the mechanism. Second, for the desired motion, the acceleration proportional to the external force is generated. It makes the desired motion continuous both in position and velocity, and an operator may change its characteristics by altering the ratio. Third, a method of external force detection is adopted that can identify the external force even when the manipulator is in motion.
The control system was implemented in an experimental system with a suspended-type manipulator. It worked successfully under some conditions.
