MAXIMUM ALLOWABLE LOAD OF FLEXIBLE MANIPULATORS FOR GIVEN DYNAMIC TRAJECTORY

This paper presents the formulation and numerical solution of the dyna mic load carrying capacity (DLCC) problem of flexible manipulators. Fo r manipulators under the rigid body assumption, the major limiting fac tor in determining the maximum allowable load (load mass and load mome nt of inertia) for a prescribed dynamic trajectory (positions, velocit ies and accelerations) is the joint actuator capacity. But for a flexi ble robot, an additional constraint on allowable deformation at the en d effector must be imposed because either lighter-weight links or oper ating at a higher speed could cause unacceptable fluctuations when mov ing along a trajectory. A Lagrangian assumed mode method was used to m odel the manipulator and load dynamics, including both joint and defle ction motions. The deflection equations are then coupled with robot ki nematics to solve for the generalized coordinates. A strategy to deter mine the DLCC subject to both constraints mentioned above is formulate d where the end effector deflection constraint is specified in terms o f a series of spherical bounds with a radius equal to the allowable de formation. A general computational procedure for the multiple-link cas e given arbitrary trajectories is described in detail. Symbolic deriva tion and simulation by using a PC-based symbolic language MATHEMATICA( R) was carried out for a two-link planer robot. The results confirmed the necessity of the dual constraints and showed that which constraint is more critical for a given robot and trajectory depends on the requ ired tracking accuracy.