Internal inspection of pipes with a diameter of around an inch usually relies on disassembly, a time-intensive and difficult task. Now, a new miniature robot developed by Toshiba provides a more reliable solution. Despite considerable research into small robots that can negotiate small-diameter pipes, it is claimed to be the first equipped to carry out visual inspections and collect foreign objects.

Remotely controlled by an operator, the miniature inspection robot is able to travel inside piping as small as 25mm diameter. It is ideal for industrial applications in such locations as electric power generation plants. Both the movement and capture of foreign objects is controlled by pneumatic pressure supplied by external equipment.

The robot itself is 110mm long and has an external diameter of 23mm at its widest point. It weighs 16g and can move at 6mm/s. The robot’s vision is provided by a highly compact 7mm, 410,000pixel CCD camera. The camera has an external diameter of 7mm and is 12mm long. It transmits high resolution images to an external monitor via a cable.

The wheels of the robot are driven by planetary reduction and worm gears, which provide the necessary drive force required for controlled ascents and descents of vertical pipes.

Manoeuvring is enhanced by a flexible link, a rubber tube between the front and back wheels that allows the robot to negotiate curves and bends. The rubber tube is fibre-reinforced along its circumference and divided into three compartments.

The camera is mounted above the robot’s two-digit hand, a rubber flexible micro actuator (FMA) with 3i of freedom.The movement of the CCD and FMA hand are co-ordinated by a wobble motor. A metal ring on the motor’s drive shaft is covered with a wave generator, a rubber doughnut with six air chambers running along its length. Adjusting air pressure in the tubes changes the pressure exerted on the metal ring and the drive shaft, moving the CCD and FMA hand in concert. The motor output torque of 7mNm provides enough power to hold an object of 70g at a distance of 1cm.

Figure 1: The Toshiba robot can crawl inside 25mm diameter pipes

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