Feel the difference

A new study in the field of haptic technology promises to bring the sense of touch to virtual worlds and make the internet more accessible to the visually impaired.

With the use of specially-designed devices, the researchers involved in the study visualise a future where online shoppers can feel the products they want to buy, or people playing interactive tennis feel the force of the ball hitting their racquet.

The researchers from Queen's University, Belfast, in collaboration with industry partners including Immersion Corporation, will spend the next three years working on the network architecture needed to support such a system.

Specifically, they will find a way to compensate for network delays that can affect the quality of haptic performance. If an internet connection was running slowly during a game of online tennis, a user might feel the force of the ball hitting the racquet seconds after impact.

Prof Alan Marshall, the principal investigator of the project, said voice delay over the internet can be about 50 milliseconds and haptics will cause an even greater delay. 'We know that when we put echo cancelling on voice it can reduce delay time, so what we need to do is to develop the equivalent of an echo canceller for haptics,' he said.

The canceller will consist of algorithms that will 'have some notion of the current state of the internet' so the system will be able to compensate for times when it is running slowly.

Marshall's project is one of a handful worldwide looking into haptics and the internet. 'Until now people have only used localised devices connected to a work station,' he said.

'What we're saying is if you're able to distribute those over a communications network, it would increase their take-up.'

Adding an extra human sense element to the internet will provide a big challenge, said Marshall, because it is only designed to handle the running speeds of audio and visual feeds.

'A visual loop generally runs at about 30Hz/min, and the haptic loop is about 1,000Hz/min,' he said. 'So what we need to do is integrate these two different loops that are running at different speeds, and that's when the compensation algorithms come in.'

Another issue that could impact running speeds is the use of stereoscopic images, but they are ideal for haptic environments.

'Stereoscopic imaging is very desirable because it gives users depth and perspective,' said Marshall. 'It's better if I want to grasp an object. If the image of an object is only given to me on a 2D screen, it's actually very hard to get depth to touch it.'

Many of the haptic interface devices used to grasp virtual objects are single-point. With those, users place a finger on the end of a robotic arm and guide their way through virtual worlds. Inside the robotic arm, three or more motors react against the movement of the user's finger and create a force against it.

'As you are moving through the environment, it feels like you're sculpting a piece of clay,' said Marshall. 'When you touch objects you can feel fabric, indentations and even the hardness of a surface.'

While the single-point devices have advanced over the years, the next big step is to increase the number of points in a device. Marshall added that some haptic researchers are looking into more 'Matrix-like' means of interacting with virtual worlds.

'Rather than using mechanical exoskeleton devices to generate physical force against your nervous system, in the future you could potentially tap directly into your nervous system,' he said. 'So rather than generating mechanical force, you could generate electrical impulse.'

There are multiple application areas for haptics over the internet. For example, Marshall said the haptic glove could be used to show someone how to assemble a part or it could be used to test the springiness in the keypad buttons on a mobile phone design.

Marshall thinks the first commercial application of this technology will be in the games industry. He used the game console Nintendo Wii as an example of how haptics can make interactive gaming a lot more fun.

'You don't get feedback from Wii,' he said, 'but could you imagine if you did?'