DLR Light-Weight Robot III

The Institute of Robotics and Mechatronics plays a major role in the field of applied robotics. Three generations of light-weight robots have been developed so far. The latest version has, like its predecessors, an outstanding load-to-weight ratio. The robot weighs just 13.5 kg and is able to handle loads up to 15 kg. Since the early nineties we had set the goal to develop a robot with a load to weight ratio of at least 1:1. LWR III turned this dream into reality.

The extreme light-weight construction was feasible by optimizing all crucial parts. FEM- and concurrent engineering methods were consequently used. The robot is composed of optimized Harmonic Drive gearboxes, the DLR-RoboDrive motor, weight-reduced safety brakes, and a lot of electronics and sensors. The light-weight robot of the third generation is a modular system. The individual joints are connected via carbon-fiber structures. The innovative hand-axis design enables the configuration as pitch-pitch as well as pitch-roll unit. Similar to the human arm the robot has seven degrees of freedom. This leads to a higher flexibility and less restricted areas compared to industrial robots.

The complete electronics, including the power converters, is integrated in the arm. A bulky external rack, as known from standard robots, is not needed. A novelty in robot technology are the integrated sensors. Each joint is equipped with a motor position sensor, a joint position sensor and a joint torque sensor. The advanced control algorithms enable vibration-free and high-dynamic movements. Besides position and velocity mode the robot can be used in a torque-controlled manner. Especially the torque-controlled mode opens new fields of application.

The individual joints are galvanically isolated. They communicate via a fiber optical bus system. All the cables are lead internally.

Besides space applications there are many terrestrial possibilities to use the light-weight robot and its technology.

Our institute followed a new path in the design of robots. We are sure that the technology will be transferred into the industry in the near future.

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