Path planning for five-part robots

  Computer simulation of a five-unit gearbox Copyright: © IGMR

Project State



Industrial robots are often used today for repetitive production tasks such as assembly, welding and painting work. With their 6 degrees of freedom, these devices offer complete mobility in space. For simpler sorting or placement tasks, however, mobility in the plane is completely sufficient. In addition to gantry systems or X-Y tables, a five-unit crank mechanism with two controlled drives can also perform such positioning tasks in the plane. This arrangement has the advantage that the drive motors can be permanently mounted and are not moved with the machine. This makes this structure suitable for highly dynamic positioning tasks.


A test bench is available at the institute for practical testing of the results. In this test bench, the gearbox is made of lightweight aluminium profiles. The cranks are driven by high-dynamic servo motors via toothed belt drives. It is controlled by the real-time control system XPC-Target, which uses control algorithms programmed under Matlab/Simulink. During the test runs, a large number of measurement signals like courses of angular errors, motor current, feedforward control, friction compensation can be used. can be viewed and recorded. The control parameters can also be changed during the run. The aim is to improve the attainable accuracy and speeds by means of improved control and a path that is better adapted to the handling device, while at the same time reducing the loads on the drive system.

Main research topics within this project are:

  • Improvement of the analysis possibilities for crank gears
  • Extension of the trajectory planning program to include advantageous point-to-point movements
  • Filtering of the acceleration curve to avoid disturbing vibrations
  • Further development of the programmed control system