• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.1
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• pp.144-153
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• 1997

The determination of the direct kinematics of the parallel mechanism is a difficult problem but has to be solved for any practical use. This paper presents the efficient formulation of the direct kinematics for double parallel robot arm. The robot arm consists of two parallel mechanism, which generate positional and orientational motions, respectively. These motions are decoupled by a passive central axis which is composed of four revolute joints and one prismatic joint. For a set of given lengths of linear actuators, the direct kinematics will find the joint displacements of th central axis from geometric constraints in each parallel mechanism. Then the joint displacements will be converted into the position and the orientation of the end effector of the robot arm. The proposed formulation is decoupled and compacted so that it will be implemented as a real-time direct kinematics. With the proposed formulation, we analyze the motion of the double parallel robot and show its characteristics. Specially, we investigate the workspace in terms of positional space as well as orientational space.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.56-65
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• 1997

This paper presents the robot program for propeller grinding. A robot manipulator is constructed by combining a parallel and a serial mechanism to increase high sitffness as well as workspace. The robot program involves inverse/direct kinematics, velocity mapping, Jacobian, and etc. They are cerived in efficient formulations and implemented in a real time control. A velocity control is used to measure the hight of a propeller blade with a touch probe and a position control is performed to grind the surface of the blade.