Assembling of Piecewise Time-Optimal and Smooth Trajectories Along Predefined Paths for Industrial Robots
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
EuroCAST 2015
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
Time-optimal trajectory planning along predefined geometric paths is an extensively discussed research topic for industrial applications in the field of robotics. The majority of
approaches dealing with this problem make use of an explicit parameterisation of the
predefined path in terms of the arc length s [1, 2]. These algorithms are applicable to
paths with relatively short length. However, the dramatic increasing in calculation time
and memory demand renders this approach extremely inefficient or even impossible to be
applied to realistic paths.
In this paper a solution method is presented where the path is split into subsequent
sections that can be handled in an efficient way. The solutions for the individual subproblems are assembled to provide the optimal trajectory of the entire path. It is crucial
that this assemblage of optimal solutions of adjacent subsections is C1 compatible at the
transition points. Moreover, the process as well as the robot impose jerk constraints. The
time-optimal trajectory does a priori not respect such jerk restrictions. This is unacceptable especially for elastic robots [3]. Taking jerk restrictions into account calls for more
complex optimization algorithms and hence leads to higher computation time [2]. In practice usually no exact jerk limitations are available but are rather deduced from practical
experience. Instead of imposing these restrictions in the optimization, it is proposed in
this paper to use a spline approximation of the determined optimal velocity trend in s × (ds/dt)^2
plane. Therewith the torque is guaranteed to be smooth and the algorithm complexity
and computation time is reduced.
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