Tohoku University knows how to climb robot using sensors
Tohoku University knows how to climb robot using sensors
Keywords: Climbing, Robots, Sensors
A research team from Tohoku University in Sendai, north-central Honshu (main island) of Japan has developed a robot which, using sensors, can climb inclinations sideways, like a crab. Tohoku is one of the six imperial universities which, led by Tokyo and Kyoto, were Japan's most prestigious,pre-war. Two wheels support the torso while four legs do the walking. The only sensors mounted on the robot are positional sensors "at the leg joints". Only a simple computer is required for control, so that the entire robot system can be designed at relatively little cost.
The prototype is still a small unit, designed to study basic performance, but if the design is scaled up, it could find uses, for example, in Japan's big logging industry, such as helping to transport logs. The prototype has a square torso measuring 50cm each side. Two wheels sandwich the torso and support its 21kg weight.
Each leg has three joints and the part of the leg connected to the torso can move both vertically and horizontally, while the part corresponding to the knee can move vertically. A cable supplies power to drive the motors connected to the wheels and legs, while a small onboard computer is used to control the movements.
Most mobile, legged robots utilise a variety of sensors, including pre-set sensors to report on the state of contact between legs and ground, but this robot employs only positional sensors, thus simplifying control circuitry and software and keeping the costs down.
The robot is programmed for movements on flat surfaces where it can walk at a top speed of 1.5kph, but the computer can also control the robot when it approaches an incline. When the robot encounters sloping surfaces, the computer notes the difference in the position sensor of the forward-most leg, calculates the force of the surface and then decides the amount of weight that the other legs and the wheels need to bear in order to achieve smooth movement. And when the robot meets a downward surface, the computer lowers the foremost leg several centimetres at a time until the position sensor of that leg stops changing,meaning that the leg has made contact with the ground, and at that point, the torso begins to move.
