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Advances in trajectory generation for robotic applications in hazardous environments

Automatic transfer robots and their manipulation in hazardous environments are regarded a key technology in many countries around the world. In her dissertation, MSc Zahra Ziaei proposes new vision-based global path planning methods for robotic path and trajectory planning in hazardous environments.

The dissertation places special emphasis on robotic applications in industrial and scientific infrastructure environments that are hazardous and inaccessible to humans, such as ITER and the CERN LHC tunnel.

“Robotic applications in radiation environments minimize the danger of radiation exposure to humans, but the robots themselves are also vulnerable to radiation. Therefore, an efficient obstacle-free path and a trajectory generation method are necessary for finding a safe path with maximum bounded velocities while the camera is the only visual feedback,” Zahra Ziaei points out.

A high degree of freedom manipulators and maneuverable mobile robots with steerable wheels, such as non-holonomic Omni-directional mobile robots, make this method suitable for inspection and maintenance tasks.

Ziaei presents the novel vision-based method by utilizing the artificial potential field, the visual servoing concepts, and the CAD-based recognition method to simultaneously generate synchronized trajectories for all of the wheels on omni-directional mobile robot.  This enables the robot’s kinematic variables to plan maximum allowable velocities so that at least one of the actuators is always working at maximum velocity.

One of the advantages of generated synchronized trajectories is that slippage and misalignment can be avoided in translation and rotation movement. The proposed vision-based method is further developed to present the path coordination method for multiple mobile robots with four steering wheels to avoid mutual collisions as well as stationary obstacles. This way, the generated paths are always in the visibility range of the overhead camera.

Public defense of a doctoral dissertation on Friday, 20 May 2016

MSc Zahra Ziaei’s doctoral dissertation in the field of Machine and Automation entitled ‘Vision-based Global Path Planning and Trajectory Generation for Robotic Applications in Hazardous Environments’ will be publicly examined at the Faculty of Engineering Sciences of Tampere University of Technology (TUT) in auditorium K1702 in the Konetalo Building (address: Korkeakoulunkatu 1, Tampere, Finland) at 12 noon on Friday, 20 May 2016.

The opponents will be Dr. Tapio Heikkilä from VTT Technical Research Centre and Prof. Arto Visala from the Department of Electrical Engineering and Automation at Aalto University.  Professor Jouni Mattila from the Department of Intelligent Hydraulics and Automation of TUT will act as the Chairman.

The dissertation is available online at

Further information: Zahra Ziaei, tel. +358 404 192019,


News submitted by: Sanna Kähkönen
Keywords: science and research