Minimum time trajectory planning for torque limited multiple axis contouring systems.

摘要

In this dissertation, the problem of trajectory planning for torque-limited multiple axis systems moving on prespecified spatial curves is treated in depth, although an optimal solution is not pursued. The resulting suboptimal trajectory planning techniques are significantly less computationally complex than existing optimal solutions and, in particular, a trajectory planning algorithm is designed for linear uncoupled multiple axis systems which is implementable in real time. A trajectory planning algorithm for robotic manipulators is also introduced which, while not implementable in real time, can be solved in "quasi real time" with the same computerized numeric control (CNC) unit which is used for robot control.;Factors which must be considered for implementation of trajectory planning techniques in real manufacturing systems are also examined. The generation of high speed constant velocity profiles is considered as well as the real time generation of velocity profiles for spatial curves with discontinuous first derivatives (curves with corners). Consideration is also given to the treatment of multiple axis systems which perform in the presence of disturbances.;Two experimental implementations and a large number of computer simulations are used to demonstrate the efficiency of the techniques presented in this dissertation. Simulation examples for a two axis SCARA robotic manipulator show that the suboptimal technique derived for robotic manipulators is only slightly lower in performance than the true optimal solution. An implementation of the trajectory planning technique developed for linear systems is performed on a Kensington Labs model 8500 positioning table, showing nearly full utilization of the capabilities of both actuators.;A second experimental implementation is performed on a Matsuura MC510V-SS high speed machining center. This example is particularly practical in light of recent advances in the field of high speed machining (HSM) which require feed drive performance not currently available from commercial CNC controllers. The implementation demonstrated contouring at over twice the maximum contouring speed of the original controller which was supplied with the machine, with an order of magnitude better accuracy. (Abstract shortened with permission of author.)