Hobby Humanoid Robot KHR3HV Rides Bike At 10k/h

An anonymous reader points out a fun robot project from Japan, writing: "The robot pedals with its feet at variable speed. The steering is done by the robot hands as with a normal bike, and remote controlled by a human. Stability is achieved by relying on the inertial centrifugal effect of the front wheel and on a gyro aided by a PID controller that takes over steering when driving in a straight line. Seems like when the robot steers his arms he also bends the waist leaning a bit into the turn. Braking is achieved by taking the feet off the pedals and pointing them down to the ground using the metal feet as friction breaks."

Comments

Slashdotted

[definate]

http://robosavvy.com.nyud.net/forum/viewtopic.php?p=32542

URL for video

[definate]

http://www.youtube.com/watch?v=SqBw7XapJKk

Stability is NOT achieved that way.

[Jane Q. Public]

A number of very thorough studies have been done. Neither "inertia" or "centrifugal effect" from either front wheel or rear contribute anything significant to the stability of a bicycle. The fact is that even today, we do not fully understand the phenomenon. The only thing we are sure of is that it does not work the way most people think it does.

Re:Stability is NOT achieved that way.

[Col Bat Guano]

We do understand how to maintain balance on a bike.

People steer into the continual tiny falls that happen all the time, actively steering the bike upright.

Re:Stability is NOT achieved that way.

[thestuckmud]

This paper" states that "contrary to common belief, gyroscopic forces play only a limited role in balancing and steering". The "feel" of a bike (pedal or motor) is said to be dominated by "trail", and aspect of steering geometry; gyroscopic torque is "non-negligible", but "much smaller than trail torques".

Gyroscopic steering is said to assist no hands bicycle riding, but I'm not a motorcycle rider and don't know about wheelie stability.

Re:Stability is NOT achieved that way.

[subreality]

Actually, no, it's still not the gyroscopic effect keeping you upright. The caster and trail (parameters of a bike's front suspension geometry) result in the bike having a self-balancing effect: as you lean to the right, it wants to steer right, and the centrifugal force of the turn pushes you left, keeping you from falling over. This works fine with zero-mass wheels that do not have any gyro effect.

At low speeds this effect is not enough for stability: with no active control it wants to turn constantly, and follows a squiggly, unsettled path. At mid-speeds it will want to turn, but they will be stable turns. At high speeds the bike becomes over-stable: if you let go mid-turn, the bike will automatically straighten itself out and return to a stable straight line. This is contrary to what you'd expect from the gyro effect, which would be to hold the bike leaning into the turn.

The gyro effect does exist, but its really not that strong compared to your weight and all the other forces involved.

Re:only 6.2 miles /H

[Anonymous Coward]

a robot rode a bike without falling over...... and you're upset he didn't go faster?

Re:you steer by leaning, not turning the handlebar

[subreality]

You should read your link more carefully. Leaning is necessary to turn, but it is not what causes you to turn.

Read the next section. If you want to turn right, you briefly turn the handlebars left. That leans you to the right. You then turn the handlebars to the right, and enter a stable right turn. To exit the turn, you turn right a little harder, which brings you vertical again, and then you straighten out.

Re:k/h?

[Noughmad]

Correct Fact: People in metric countries actually talk in km/h.