Robots work more safely if controlled by another technology

Robots carry out their tasks more safely if controlled by another technology, making them more suitable for use in the care sector than the existing form of robotics which perform repetitive tasks, a study has found.

In the coming years, the use of assistive robotics will become ever more important due to the increased ageing of the population and the steadily rising costs of care, according to researchers from University of Twente in The Netherlands.

Already, robot technology is very valuable for people with a physical handicap when it comes to carrying out everyday tasks.

A robot arm on a wheelchair or table, for instance, enables a person to open the door or pick up a glass by themselves, meaning that this group of patients is less dependent on health care workers and also increasing the patients' quality of life.

However, in practice, the existing form of robotics is not ideal for a care-support function because the systems are based on robots that carry out repetitive tasks in industry, researchers said.

These robots generally behave as rigid and less safe systems - the system that controls the electromotors (actuators) lacks the flexibility that is required in an unfamiliar domestic environment, they said.

The robot will often seek the shortest route from A to B, taking little or no account of obstacles or persons in its immediate surroundings. And so there is a relatively large risk of the robot or the obstacle being damaged.

Adding a kind of elastic spring to the actuator can make the robot, or the robot arm, much safer, as shown by researchers.

This spring ensures that the robot behaves in a more elastic way - it yields when it collides with an obstacle. This technology (known as the variable stiffness actuator) has never before been used in assistive robotics, researchers said.

"We believe this can form the basis of a new generation of robots in the care sector - robots that can carry out more everyday tasks in a safer way, while simultaneously remaining extremely precise," said Stefan Groothuis from University of Twente.

A further improvement to the robot arm has been achieved by positioning the actuator differently. Normally each joint has one electromotor, enabling this joint to move.

In the human body this movement is achieved by the muscles around a joint, such as in the hip joint, researchers said.

But humans also have various muscles that move two joints simultaneously, such as the biceps, which moves the elbow and shoulder. This principle has been incorporated in the research and it provides the robot arm with other elastic properties, they said.