Abstract

A model-based approach to the generation of control strategies for
compliant motion control is presented.  Manipulative operations such
as part-mating and grasping must be achieved despite positioning
errors of workpieces.  Applying damping control, a robot can modify
its motion according to reaction forces acting on it in order to
achieve the operations.  An admittance matrix, which characterize the
robot motion, depends upon the operation to be achieved.  It is
difficult for human operators to setup the admittance matrix
adequately for a various kind of workpieces.  In addition, operations
are often so complex and intricate that they cannot be achieved by
single control laws.

In this paper, we will develop a technique to derive control
strategies for part-mating operations.  First, the process of
part-mating operations is analyzed with regard to how the workpieces
contact each other.  Kinematic and static property at each contact
state is also analyzed.  Second, we derive a method to compute control
parameters in damping control law that can eliminate positioning
errors.  Third, a systematic method for mapping the force information
into individual contact states is developed so that the robot can
recognize the current process state.

Keywords: constraints, mechanical contacts, motion planning,
geometric model, compliant motion