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ROBOTICS

VEX kiwi drive

Three wheels. Translation and rotation together.

  • Omnidirectional drive
  • Kinematics
  • Independent design
The VEX robot with its three-wheel omnidirectional drivetrain and mechanisms.
My VEX robot, built around the independently developed three-wheel drive.

Independently arriving at a kiwi-drive layout and writing its movement controls, including simultaneous translation and turning.

I wanted omnidirectional motion without the extra drive wheels and motors of the layouts I knew. I had not seen a kiwi drive at the time, so I worked through a three-wheel arrangement myself.

My contribution

  • Develop the three-wheel, three-motor drive arrangement.
  • Write the directional and rotational movement controls from scratch.
  • Lead most of the robot’s design and build.
  • Integrate additional mechanisms, with a teammate contributing to the catapult.
01 / THE PROCESS

Working through the motion

The controls combined each wheel’s contribution to the desired movement, with adjustable wheel offsets. They could command movement in any direction and add turning at the same time.

The result was an independently developed implementation of an established drive type. What mattered to me was arriving at the idea through my own reasoning and seeing it work on a physical robot.

02 / THE PROCESS

A complete competition robot

The robot also had a catapult, an extending front ram and a rear climber. A teammate contributed to the catapult; I did most of the overall build and integration.

We took part in smaller inter-school competitions. The project remains a favourite example of the enjoyment I get from building something I have worked out for myself.

WHERE IT LANDED

A physical result from independent reasoning.

The robot could combine translation and rotation. Developing the layout and controls myself helped me understand how the individual wheel motions combine into the movement of the whole robot.

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