Service Robots Case Studies

Schunk, Germany - IFR Robot Supplier Member

Service robots revolutionize clean-up of the Sydney Harbor Bridge

February 2014

While research continues under laboratory conditions elsewhere, Australian robotics specialists showed off a concrete application at the SCHUNK Expert Days on Service Robotics: Using the Sydney Harbor Bridge as an example, they show how service robots will soon revolutionize how steel structures are serviced. The robust lightweights are slated to go into serial production at the end of 2014. At their core is a lightweight arm designed by SCHUNK.

Development time in service robotics is decreasing rapidly. Barely a week can go by without another report on new designs and applications. What just a few years ago was considered nothing more than scientific dreams pursued by a handful of research institutes obsessed with robotics is now well on its way to catapulting an entire industry to a new level of development. The spectrum of real applications is not limited to autonomous vacuum cleaners or lawn mowers. Instead, robotics 2.0 offers the potential to take over physically straining or exhausting tasks from humans to a much broader degree than ever before. That this is reaching unstructured environments is illustrated by the "Bridge Blasting Robot" by SABRE Autonomous Solutions, which is being used to service the Sydney Harbor Bridge.

The idea of automating the cleaning of steel structures was born in Sydney about seven years ago. Under the direction of Professor Dikai Liu, and in cooperation with NSW Roads and Maritime Services, the Centre for Autonomous Systems (Department of Engineering and Information Technology) at the University of Technology Sydney (UTS) developed an automated sandblasting robot for servicing steel bridges. Today, SABRE Autonomous Solutions, a UTS robotics startup, is responsible for pre-commercial implementation as well as marketing. Burwell Technologies, Australia's leading provider of sandblasting equipment, has also become involved as an investor and has begun selling this next generation system.

More precise and perseverant than man

After a successful testing stage, the sandblasting robot has become part of the standard equipment used by the maintenance team of the world-famous Sydney Harbor Bridge. With a span of 503 meters, an arch crown height of 134 meters and 52,800 tons of steel, it is one of the heaviest and longest steel arch bridges in the world. As with any steel bridge, the Sydney Harbor Bridge must be continuously maintained and protected against corrosion. This includes sandblasting and repainting 485,000 m2 of steel, or about 68 football fields. A single coat requires about 30,000 liters of paint.

Rosie and Sandy, the two blasting robots, confidently and tirelessly blast dirt, rust and old paint from the steel girders. While some of the workers have to take a break every 15-30 minutes due to the extreme physical strain, the two powerful robots blast their way through meter after meter without interruption - much more persistently, quickly and precisely than a human ever could. The robots take about 50 minutes to complete a segment. Using a Kinect sensor and special algorithms, a mapping system calculates the sandblaster's exact path, preventing collisions. The operators, in turn, monitor the sandblasting process from a safe distance.

Since the two service robots have been in operation, the safety, cost effectiveness and quality of the sandblasting work has risen markedly, confirms Greg Peters, Engineering Design Manager at SABRE Autonomous Solutions. "Due to the fatigue while sandblasting, even experienced workers are unable to achieve such consistent results", said Peters. And operating the system could not be simpler: The lightweight robot is manually positioned on a simple rail system. It then automatically scans the steel structure, generating a threedimensional map. The work begins once the operator initiates the sandblasting process by remote.

Mobile lightweight arm that can take a pounding

The core of both sandblasting robots is a LWA 4 lightweight arm with very high load capacity designed by SCHUNK, specialists in clamping technology and gripping systems. Secured under a protective cover, the lightweight arms remain unaffected by rust, dust, and humidity, as well as the vibrations and shifting stresses of sandblasting. To change location, the robot can either move along the tracks to another location on-site, or be dismantled into compact units and taken away by hand. The unique combination of mobility, robustness, power and lightweight construction make the LWA a multi-functional helper in service robotics. Unlike classic industrial robots, it is specifically designed to automate varying tasks in the immediate environment of humans. These include inspection and assembly tasks, along with use in assistance systems, which also includes the sandblasting application in Sydney. A consistently high repeat accuracy of +/- 0.1 mm provides optimal conditions for precise operations. The lightweight robot is both portable, i.e., movable, as well as mobile. It can carry a maximum of load of 15 kg.

Its modular design allows the number of degrees of freedom, drive power, and type and length of spacers and joints to be freely defined. Since the boosters and drive control system are directly embedded in the lightweight arm, the system does not require a separate control cabinet. Instead, the entire control and regulator electronics are integrated into the joint drives. Position, speed and torque can be regulated flexibly. Integrated intelligence, universal communication interfaces, and data transmission and power supply cable technology allow the lightweight arm to be integrated quickly and easily into existing control concepts. It can also be controlled by embedded PCs. The individual modules can also be easily controlled using the CAN interface that comes standard in all LWAs, with optional speed or power control. The lightweight arm is particularly energy efficient due to its lightweight, highly rigid design, which pays dividends in mobile applications in the form of long runtimes.

Whereas before, sandblasting required teams of up to three workers as well as significant safety precautions, on the Sydney Harbor Bridge, one operator controls and monitors up to two robots. Hazardous, physically straining and, at times, even harmful routine tasks are almost entirely performed by robots. Once a robot finishes a segment, a worker takes the blaster gun and sees to the more complicated detail work. The payback period for the robot system is around two years. SABRE is currently developing another mobile sandblasting robot in addition to those used for bridges, weighing a maximum of 65 kg and that can be easily transported and used for numerous other applications. The central element of this new robot is also an LWA lightweight arm by SCHUNK.