Spider-Man can leap off tall buildings and swing through the New York skyline by shooting a dragline from his wrist.

Now there is a spider-inspired robot that can perform the same trick. It could be used to explore rocky planets, spinning itself a line to abseil down when it comes to the edge of a cliff, for example.

“Spiders travel around surface-free space between tree branches and can position themselves in mid-air,” says , who has developed the robot alongside colleagues at the Bio-Inspired Robotics Lab at ETH Zürich in Switzerland.

“There is no technology that allows a robot to do the same thing except flying, and then the amount of payload they can carry becomes a major issue.”

To spin the dragline, the robot uses thermoplastic adhesives, which are solid at room temperature but form a liquid when heated to around 70 °C.

A stick of the material is fed into a small chamber and heated, before being fired out of a nozzle into the open air, where it begins to harden into a line. As it is pushed out of the nozzle, the line passes between two motor-controlled wheels, which grab it and help to pull the cable out of the device.

Hold the line

Because the material has not yet fully cooled, it remains sticky, allowing the line to attach itself to any solid surface.

The robot then uses the wheels to grip as it travels down the line at a speed of around 12 centimetres a minute, says Wang.

At the moment, the system only produces vertical draglines, but the team plans to modify it to produce horizontal lines as well, allowing the robot to spin webs between surfaces. This would enable the robot to carry heavy objects across cracks or craters, says Wang.

at the Natural Robotics Lab in Sheffield University, UK, says such a robot could be really useful when faced with difficult terrain. “It could also be used on other planets where robots will encounter environments that haven’t been shaped to our needs yet, so you don’t know what capabilities you will need,” he says. “A robot that is flexible would be ideal in that kind of environment.”

Last year the team unveiled a sticky-footed robot that could climb walls while carrying up to five times its own mass.

Journal reference: Bioinspiration & Biomimetics,

ROBOTS need help navigating their surroundings and sophisticated location systems to keep track of their position. Now the same technologies are being adapted to help blind people navigate indoor and outdoor spaces independently.

One such system, being developed by Edwige Pissaloux and colleagues at the at the Pierre and Marie Curie University in Paris, France, consists of a pair of glasses equipped with cameras and sensors like those used in robot exploration. The system, unveiled at a talk at the Massachusetts Institute of Technology this month, produces a 3D map of the wearer’s environment and their position within it that is constantly updated and displayed in a simplified form on a handheld electronic Braille device. It could eventually allow blind people to make their way, unaided, wherever they want to go, says Pissaloux. “Navigation for me means not only being able to move around by avoiding nearby obstacles, but also to understand how the space is socially organised – for example, where you are in relation to the pharmacy, library or intersection,” she says.

Two cameras on either side of the glasses generate a 3D image of the scene. A processor analyses the image, picking out the edges of walls or objects, which it uses to create a 3D map. The system’s collection of accelerometers and gyroscopes – like those used in robots to monitor their position – keeps track of the user’s location and speed. This information is combined with the image to determine the user’s position in relation to other objects.

The system generates almost 10 maps per second which are transmitted to the handheld Braille device to be displayed as a dynamic tactile map. The Braille pad consists of an 8-centimetre-square grid of 64 taxels – pins with a shape memory alloy spring in the middle. When heat is applied to the springs, they expand, raising the pins to represent boundaries. The Braille version of the map is updated fast enough for a visually-impaired wearer to pass through an area at walking speed, says Pissaloux. Seth Teller, who develops assistive technologies at MIT, calls the work exciting and ambitious.

“The maps are transmitted in real time to a handheld Braille device that becomes a dynamic tactile readout”

This is not the only robotics project to be re-purposed. Software that predicts how far a robot has travelled based on information from its on-board sensors is being modified to track a person’s movements based on their stride length. The low-cost system, being developed by Eelke Folmer and Kostas Bekris at the University of Nevada in Reno would help blind people navigate around buildings using just a smartphone.

The new system uses freely available 2D digital indoor maps and the smartphone’s built-in accelerometer and compass. Directions are provided using synthetic speech. To help the smartphone calibrate and adjust to a user’s individual stride length, the user must initially use touch to detect the landmarks in their environment, such as corridor intersections, doors and elevators. The system will be presented at the IEEE International Conference on Robotics and Automation in St Paul, Minnesota, in May.

David Ross at the in Decatur, Georgia, says that the sensing problems faced by robots and blind people are similar but there are big differences. “Sensing systems developed for mobile robots may have some application, but must be adapted considerably to suit a wide variety of human needs and situations,” he says.

FORGET hydrogen: ammonia could be the answer to developing an emissions-free fuel for cars.

Ammonia produces just nitrogen and water vapour when burned and, unlike hydrogen, it is relatively easy to store in liquid form. That means transporting ammonia will not require costly new infrastructure, says John Fleming of in Lubbock, Texas.

Fleming and at Texas Tech University, also in Lubbock, are developing a system to produce ammonia that can be installed in filling stations. Powered by mains electricity, it first produces hydrogen from water using electrolysis, then combines it with nitrogen from the air to produce ammonia.

To achieve this, the researchers have adapted the Haber-Bosch process used to make ammonia industrially. Their version works on a small scale and can make ammonia fairly cheaply.

In their system, a piston rapidly compresses hydrogen and nitrogen, heating the gases to 400 °C. The mixture is fed into a chamber containing an iron oxide catalyst, which sparks a reaction that further heats the gases and generates ammonia. In a third chamber, the mixture decompresses and cools down to room temperature. As it does so, it pushes against another piston, from which mechanical energy is recovered and fed back to the compressor, significantly cutting the process’s power consumption.

Finally, a heat pump cools the mixture down to around -75 °C, liquefying the ammonia for collection.

The team say the whole system could fit within a standard container and could therefore be transported by truck for installation at filling stations, where it could make between 4000 and 40,000 litres of ammonia per day. Maxwell adds that the system has a modular design, so it can easily be scaled up to produce more. The ammonia could be made for just 20 cents per litre, they claim.

, a chemist at the University of Oxford, says that a mobile unit that can turn water and electricity from renewable energy sources into fuel ammonia would be useful in remote areas. Fleming and Maxwell are already working with the US army and air force, who have each expressed interest in using the technology on the battlefield.

However, Tsang is not convinced that the hydrogen needed to make ammonia can be produced economically using electrolysis. Fleming and Maxwell claim to have got round this hurdle, too (see “Hydrogen on the cheap”).

Conventional cars can already make use of ammonia – they can run on a mixture that is 90 per cent gasoline and 10 per cent ammonia, says Fleming. So-called flexible-fuel vehicles, which use a mixture of gasoline and ethanol, could also be modified to run on a fuel that is up to 85 per cent ammonia. Such vehicles have sensors that constantly detect the exact proportion of gasoline and ethanol being fed through, and adjust their fuel injection and spark timing accordingly. To run on ammonia, the vehicles would need to be reprogrammed and equipped with a fuel tank capable of storing ammonia under pressure.

“Conventional cars can already run on a mixture that is 90 per cent gasoline and 10 per cent ammonia”

The team are also designing an engine that could run purely on ammonia. Called the Linear Electric Internal Combustion Engine, it is based on an existing design, known as a free piston engine, in which the burning air and ammonia mixture moves a piston forwards and backwards. This is used to drive a generator, the electricity from which powers a motor that turns the wheels.

The ships would sail to a suitable location, drop anchor and start generating electricity from wave energy. Once their batteries were fully charged they would return to shore and feed the electricity into the grid.

Unlike conventional wave-power devices, the ships would not need undersea cables to link to the electricity grid, says at Boston University and the Fraunhofer Center for Manufacturing Innovation, also in Boston. These cables typically cost more than $500,000 per kilometre and account for a significant fraction of the cost of conventional wave-generated electricity.

The 50-metre-long ships would harvest wave energy via buoys attached to their sides by pivoting arms. While the hull remains relatively stable, the buoys would bob up and down on the waves, causing the arms to pivot back and forth and drive a generator producing up to 1 megawatt of electrical power. The batteries are planned to have a capacity of 20 megawatt-hours, so the ships would have to stay at sea for at least 20 hours for a full charge. Sharon presented the concept at the Conference and Expo in Boston.

Unlike conventional wave-power devices, the power-generating mechanism will not have to withstand severe storms, as the ships could be kept in port during bad weather. Fixed wave-power generators must be built to cope with extremely high waves, which adds substantially to their cost, Sharon says. Costs could be cut further by retrofitting existing vessels, which could either have their own engines or be towed out to sea and back.

Sharon used 3D printing to produce a prototype, and tested it in a wave tank. He calculates that the system should generate electricity at a cost of $0.15 per kilowatt-hour. This would make it cheaper than energy from existing wave systems, which costs . Offshore wind energy costs from $0.15 to $0.24 per kWh, and solar power around $0.30 per kWh.

, director of the atmosphere and energy programme at Stanford University in Palo Alto, California, calls the idea “very creative”. He notes that unlike electricity from many other renewable sources, power from the batteries could be held back and used at times of peak demand.