Laboratory for industrial robots

Mobility and sensitivity of the robot

Interesting techniques

KUKA LBR iiwa 7 R800

The LBR iiwa belongs to the lightweight robots and is a redundant serial kinematic or articulated robot with 7 axes. All drive units and current-carrying cables are routed inside the robot. Each axis contains a number of sensors that provide signals for robot control (e.g. position and impedance control) and are also used as a protective function for the robot. For example, in each axis, axis range sensors monitor compliance with the permissible axis range and torque sensors monitor compliance with the permissible axis loads. This function in particular enables this robot to be used collaboratively, i.e. in interaction with a human.

Robot switch cabinet

The switch cabinet is the basis for the robot test bench for investigating the path accuracy on the drive side. It contains the Lenze 9400 series drive technology with interfaces for real-time communication with a freely selectable control system. The servo motors of the robot system are connected to the drive system with the open and configurable cascaded single axis control loops. In combination with the switch cabinet, a higher-level control system offers a freely configurable and parameterisable control system with a short cycle time (1 ms), a restriction-free specification of own trajectories and an interface for model-based torque-current pre-control.

MoveInspect HF

With the MoveInspect HF (high frequency), dynamic processes can be recorded and analysed three-dimensionally. The high-end version is able to record data of any number of measuring points with up to 490 Hz for an unlimited period of time. For each point in time, MoveInspect software determines, among other things, the 3D coordinates of object points, 6-DOF coordinates of solids and the velocities of object points and solids. The calculation is based on the principle of spatial triangulation of images (photogrammetry) and is carried out fully automatically by the evaluation software.


Research / main areas of work

Observer-supported increase of the path accuracy of industrial robots under consideration of joint elasticities

Despite stiff construction, articulated arm robots are excited to vibrations in highly dynamic applications primarily due to joint elasticities and looseness. This leads to greatly reduced path accuracy. For control compensation, these influences must be measured and quantitatively analysed on the output side. The internal robot sensor system (angle encoder on the drive side) of most industrial manipulators cannot exactly reproduce the real path. High-performance 3D camera measuring systems that allow high-frequency scanning of the TCP path (tool centre point) are a possibility for precise metrological recording of highly dynamic trajectories. A cascaded methodology is used to improve the output-side path accuracy of serial robots for highly dynamic robot paths. This consists of three sub-steps: a kinematic and dynamic modelling and calibration, the compensation of the non-linearly coupled dynamics by means of model-based torque pre-control and the reduction of remaining path errors by iterative learning methods based on external camera measurements. This results in an overall effective concept for automated calibration and optimisation of the accuracy of highly dynamic trajectories of industrial robots by a kind of automated teach-in.




KUKA LBR iiwa 7 R800


Franke Emika | Puma

Mitsubishi SCARA, MELFA RH-20SDH8545-S15

ABB IRB 2600-20 kg / 1.65 m

MoveInspect HF



The team


Every semester, the project laboratory takes place in the area of compulsory electives for MAB-AM/PS, MBI, WIM students (6th semester). This includes the programming of the industrial robot KUKA LBR iiwa 7 R800 for robot-supported manufacturing, assembly and order picking.