Standing on its own two wheels: Yamaha say self-balancing bike will help minimise accidents

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Last year, Yamaha pledged to eliminate motorcycle accidents with a three-tiered approach focusing on skills, connectivity and technology.

A major part of this involves developing self-balancing systems to increase stability at low speeds, and now the firm have showcased a prototype, based around the Japanese-market R25 sportsbike.

The Advanced Motorcycle Stabilisation Assist System (AMSAS) uses a six-axis Inertial Measurement Unit (IMU) working in tandem with two actuators, one providing small inputs of drive to the front wheel, the other making minute adjustments to the steering.

Yamaha technicians with a self-balancing R25

The system not only works while travelling at slow speeds, but the actuators also kick in as the bike sets off, in both cases increasing stability and allowing the rider to move at walking pace without any embarrassing tip offs or drops, regardless of their skill level.

Project leader, Akitoshi Suzuki, said: “When starting or stopping, the drive actuator fitted to the front wheel aids with stability, and from there up to about 5kmh (around 3.1mph), the steering actuator attached to the bars takes over.”

Currently the system has only been fitted to the YZF-R25, but as no modifications are required to the motorcycle’s frame, it could theoretically be fitted to any production machine.

Yamaha self-balancing front wheel actuator

The electric drive actuator is attached directly onto the front wheel’s hub and resembles motors found in washing machines, but smaller. It enables the bike to remain upright at a standstill by using the dynamics of an inverted pendulum, similar in principal to balancing a broom upside-down in your palm.

The steering actuator, meanwhile, is attached directly to the triple clamp, below the level of the bars and on the YZF is partially obscured by the tank shroud with its miniscule bar inputs akin to those made by a rider while trying to balance a trials bike at low speeds or a complete standstill.

The current system, says project leader Suzuki, represents the halfway mark towards seeing such systems reach customer bikes, but there is still work to be done.

Self-balancing Yamaha R25 headstock actuator

“From here on, we’ll be working to downscale the sizes of the various components, as we want to develop it into a platform not just for motorcycles, but one that is also adaptable to a wide range of other personal mobility applications, such as bicycles,” said Suzuki.

Yamaha have experience of self-balancing systems having developed a self-balancing electric bike in 2017. Dubbed the ‘Motoroid’, it approached the self-balancing conundrum by actively shifting its centre of gravity.

This Active Mass Center Control System (AMCES) worked by rotating the battery pack, slung under the frame, either left or right allowing the bike to stand up off its stand and remain upright unassisted. It could also react to the rider’s weight and riding style to maintain optimum balance.

Yamaha's 2017 Motoroid concept uses some self-balancing elements

Both Yamaha systems aim to eliminate the 5% of accidents caused by low-speed riding errors, allowing the rider to focus on recognition of potential hazards and more time to make the correct decision to avoid them.

Yamaha self-balancing tech in detail

  • Gravity manipulation: Changing the centre of gravity is an idea Yamaha explored with the ‘Motoroid’, which could shift its battery pack left or right.
  • Driving force: The electric drive actuator uses an inverted pendulum and tiny drive inputs to keep a bike upright at standstill and stable while the bikes sets off or comes to a halt.
  • Technology to be delivered: One target market for self-balancing bikes is the delivery sector which, by its nature, requires numerous start/stop journeys at low speeds.
  • Steering input: Miniscule changes in handlebar angle at speeds up to 3mph provide the main stabilising force when the bike is moving slowly, akin to those made while balancing a bicycle at standstill.
  • Next small steps: The current system, tested on a YZF-R25, is the halfway step before the technology reaches customer bikes. The next moves are to reduce the size of the actuators.