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Learning from robots

	BEST FOOT FORWARD: The team from left: Dr Chew Chee Meng, Huang Weiwei, Albertus Hendrawan A, Tian Bo and Dau Van Huan.

Robots have been to space and back. They have gone on dangerous missions, crossing deserts and going to the bottom of the sea. Moving along on wheels or other contraptions suitable for the terrain they work on, they can be pretty mobile and efficient — even without legs.

However, the challenge for many roboticists is still to build intelligent humanoids – bipedal robots. Dr Chew Chee Meng, who leads a team of budding roboticists at the Department of Mechanical Engineering, explains that robots with two legs which can multi-task are really the Holy Grail in robotics. Many robots today only have functional arms. But legs? Those are tougher to build, especially if they are to walk up and down stairs as well as slopes efficiently.

In building humanoids, you study human beings to get your robot as human-like as possible. Once that is achieved, the robots could actually shed light on how humans function – actions that involve mechanisms that the human eyes cannot see, for example. "We may one day, through robots, discover how to enable those who have lost the ability of their limbs, walk again," mused Dr Chew.

He and his team have just given birth to a new biped at NUS. Barely a month old, it is the team's third biped prototype. Measuring 1.2m tall, it would weigh about 60 kg when fully equipped with a head, arms and an outer shell which would give it a more human appearance. Its walking speed is close to a human's, about 0.7m per second. It can currently balance on one leg – quite a feat – for a newly born.

This time round, they managed to give the robot better drive mechanism. Harmonic drives are now used for all the joints – this enables larger "torque" or force for the joints. "With our earlier biped, the gear heads were not suitable for high torque applications. The actual implementation has resulted in high wear and tear in the drive mechanisms. Now we don't have this problem," said Dr Chew.

"Being able to exert and withstand large torques at the joints are important as the robot structure is subject to regular impact needed to support exchange between left and right legs during walking.  It can also perform tasks such as squatting with more ease," he explained.

The Honda humanoid, currently the team's role model for their biped, has taken the famous team in Japan more than 10 years to be developed to what it is today.  ASIMO, billed as the world's most advanced humanoid robot, was estimated to have some US$100 million put into its development.

Though their robot currently consists of only two legs and a trunk, Dr Chew is proud of his team, comprising four postgraduates with no industrial experience. The Honda team, whereas, has some 30 full-time engineers working in the first 10 years of the project. Despite tremendous effort by the Honda's team, the robot is still far from perfect. For example, it is still unable to move about freely in natural terrain. So far, it has only been successfully implemented in known and fixed environment.

 "The robot needs to be able to traverse most terrains that humans usually experience so that it will be able to co-exist with human. Our team will actively explore new locomotion algorithms or gaits for bipedal robots.  The new gaits must be robust and efficient," said Dr Chew.

His team is now working on getting their biped to climb stairs and slopes, as well as to walk with different speed, and to turn. "We are confident that we will be able to achieve these behaviours in few months' time," said Dr Chew.

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