Yamaha Is Developing Electric Power Steering for Motorcycles

Admin · March 30, 2022

Yamaha’s new electric power steering system is currently in use on some of its works motocrossers. (Yamaha/)

Yamaha’s announcement that it will run a prototype electric power steering (EPS) system on works racebikes in this year’s All-Japan Motocross Championship might well be the first step toward a whole new generation of rider aids—and one that completes the circle that was started by ABS and traction control.

But is turning the bars on a motorcycle really that much work? All bikes have to strike a balance between stability and maneuverability, and to get the best of the latter there are usually compromises on the former that need to be addressed with the addition of a steering damper. Yamaha’s EPS promises to eliminate that compromise by emphasizing rider input while resisting outside influences on the front wheel’s direction, thus allowing motorcycle setups and geometries that couldn’t be considered without it.

Related: Honda Patents Self-Steering Motorcycle

The system uses a torque sensor, a control board, and an actuator to add steering assistance without feeling unnatural. (Yamaha/)

The system works via three main components. A magnetostrictive torque sensor measures the movement of the steering and the amount of force being applied by the rider, sending that information to a control board. That board, in turn, tells an electronic actuator bolted to the front of the headstock and geared to the steering stem how much assistance to add. It’s basically the same technology used in ebicycles to measure the effort being put into the pedals. The harder you pedal, the more electric assistance they add. With EPS it’s the same, just on the steering.

Yamaha says that the initial, motocross version of the setup does most of its assistance at low speeds, when you’re likely to use larger movements of the bars, and as you go faster it turns its focus to its second role as a steering damper. Because it can tell the difference between rider inputs and external forces, the steering actuator can counteract bumps or road surface changes that might try to change the bike’s course. In competition, the result should make the bikes less physical to ride, leaving the rider with more strength and stamina at the end of races. Yamaha says that despite the system, the bikes still feel natural to the riders.

Related: Honda Is Developing a Steering Assist System for Bikes

Motocross is just the start. Yamaha says the system is developed with “an eye on installation on a variety of motorcycles.” It’s clearly compact enough to fit virtually any bike and existing machines wouldn’t need a ground-up redesign to incorporate it. On superbikes, it could easily become a natural next step from the sort of active steering dampers already in use, but for the future, the addition of an electric actuator controlling steering angle opens the door to many other possibilities.

The system appears to be compact enough to be fitted onto almost any type of bike. (Yamaha/)

Modern bikes already use ride-by-wire throttles and ABS brakes that give on-board computers a level of influence over two of the three main controls. Power steering means the third rider input can now be computer-governed too. Honda and BMW have both previously demonstrated self-riding motorcycle prototypes, and Yamaha has created the Motobot robot rider that’s able to lap circuits on otherwise standard machines without any human control input. The computer technology for auto-riding bikes is already there, so EPS simply adds the last piece of the jigsaw to put control into the hands of those computers.

Combined with the sort of inertial measurement systems fitted on many modern bikes, the potential is vast. Paired with lane-monitoring cameras and the sort of radars now appearing on bikes, we see the possibility of semi-autonomous riding. Lane assist, for instance, or even object avoidance, are easy to imagine, as well as next-generation traction control systems that could let anyone control a slide like Rossi or force a tighter line if you start to get target-fixated on the outside of a corner.

Related: Motorcycle Rider Aids

The system also introduces the potential to rethink some of the steering and suspension geometry ideas now in use; future bikes could have more radical setups that rely on the EPS for control. Modern fighter jets have physics-bending levels of responsiveness because they’re designed to be inherently unstable, relying on computers to make constant adjustments just to keep them in the air while leaving the pilots to concentrate on other things. With EPS, who’s to say motorcycles couldn’t go down the same route?

Yamaha certainly isn’t alone in believing in this sort of system. We’ve already seen Honda’s Riding Assist concepts, which use automatic steering to balance themselves even when stationary, and BMW’s prototype self-riding R1200GS was demonstrated at CES a few years ago. Beyond that, electronics giant Bosch—already leading the market in ABS and traction control equipment for bikes—is hard at work on its own auto-steering setup. Yamaha’s EPS might be restricted to works motocross riders for now, but it’s unlikely to be long before something similar shows up on the road.

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