On optimal drive train design in industrial robots

In this paper optimization is used to determine which gearboxes to use in an industrial robot. The paper also presents a procedure where tradeoff information is generated based on consecutive optimizations. Thereby the method provides the designer with information about critical tradeoffs between conflicting objectives. This type of information is very valuable when negotiating between different design alternatives. Generating these tradeoffs is traditionally a time consuming process, but by introducing optimization this process can be partly automated. The design variables studied are composed of continuous and discrete parameters, where the latter are associated with different gearbox alternatives and the continuous variables with the speed-torque limitation of the gearboxes. A non-gradient based optimization algorithm which can handle mixed variables problems is used to solve the highly non-linear problem. The outcome from an industrial point of view is minimization of cost and simultaneously balance the trade-off between lifetime and performance.