The upcoming Rivian R1S and R1T electric vehicles feature a growing suite of cool party tricks with practical applications, and a new patent filed for a vehicle maneuver called the “K-Turn” by Rivian seems cleverly simple.
Rivian CEO RJ Scaringe was “secretly” showing anybody who would listen (including yours truly) videos of a Rivian development vehicle performing the “Tank Turn” maneuver for years, where the electric motors shift the torque of the wheels to spin the vehicle in place. That turning trick was confirmed for the final vehicle back in 2019, but the list of motor tricks grows with a new patent caught by RivianOwnersForum.com.
Looking at the patent description and descriptive images and diagrams, the K-Turn is an extension of the steering angle, where torque management of each individual wheel assists the mechanical steering linkage at its limit to improve turning angle and vehicle maneuverability. From the patent (via PatentScope):
The K-turn mode is engaged in response to determining that an amount that at least one of the front wheels of the vehicle is turned exceeds a turn threshold. While operating in the K-turn mode, forward torque is provided to the front wheels of the vehicle. Further, backward torque is provided to the rear wheels of the vehicle. Yet further, the rear wheels of the vehicle remain substantially in static contact with a ground while the front wheels slip in relation to the ground.
So it sounds like the K-Turn is similar to the Tank Turn, but the rear wheels can be kept static, or locked to create a pivot point for the torque of the other wheels to rotate the vehicle’s orientation without a massive footprint required, from what I can gather. It’s likely this trick could be tuned to work on vehicles in various motor configurations.
It appears to be activated at steering lock, which patent Fig. 5 describes as the “turn threshold,” with another label for “K-Turn Mode” labeled a few degrees clockwise beyond the threshold. It looks like the driver turns the wheel beyond lock to activate the unique torque feature.
Patent Fig. 6 and Fig. 7 show the various directional applications for how the system determines wheel lock, wheel slip and torque application. Considering all of that capability is already likely hardwired into Rivian’s current lineup, it’s nice that the automaker is fleshing it out with as many applications it may come up with.
However, in reality, I think this feature will be used a majority of the time in stand-still traffic, when the inevitable impatient Rivian driver wants to edge out of the line into the emergency shoulder to “see what’s up” ahead like it will change anything or provide any relief, while also showing off their cool trick. That, and of course easier curbside parking.