Fuel cars can also perform spins in place; what is the difference with Xiaomi's Smart Chassis?
The spin-in-place demonstration shown in Xiaomi's Smart Chassis pre-research technology is implemented based on the Super Quad-Motor System. Compared to spins achieved via fuel-driven four-wheel drive or electric four-wheel drive methods, it offers many advantages.
Controllable both inside and outside the vehicle. Users can operate it from inside the car or remotely via the mobile phone APP. The angle is adjustable; for example, if you find the vehicle parked slightly askew after getting out, you can use the APP to adjust the angle and straighten the car. We have also integrated intelligent driving perception information, which is essential for remote spin-in-place functionality. For instance, if insufficient road conditions or obstacles are detected, the spin-in-place function will automatically stop.
Adjustable spin speed: go fast or slow as desired. This requires the Vehicle Control Module to coordinate and call upon the quad-motors, brakes, steering, and suspension systems to precisely control the torque, speed, and direction of the four motors, ensuring consistent slip and rotation speed across all four tires. The steering system adjusts wheel angles, working in synergy with the motors to achieve rotation, while the suspension system reduces lateral forces to ensure stability and comfort.
Capable of seamless continuous spins in place. This heavily tests the cooling capacity of the motors. Xiaomi's Super Quad-Motor System features a powerful cooling system. The stator uses a dual-circuit three-dimensional oil-cooling technology, which increases effective heat dissipation area by 100% compared to the industry-standard single-direction oil circuit design. The rotor adopts an S-shaped oil circuit design, achieving synchronous cooling of the shaft and iron core. This cooling system, when applied to the rear-drive system of the SU7 Ultra, delivered an impressive result of reducing motor temperature by over 30 degrees Celsius during Nürburgring tests.
The front motor of the Xiaomi Super Quad-Motor System has a peak torque of 380N·m per unit, while the rear motor has a peak torque of 635N·m per unit. Combined with high-frequency torque coordination control at 500 times per second, it can easily perform spins on high-adhesion surfaces. In extreme cases, it can rapidly feedback and automatically correct the vehicle's attitude, ensuring safe driving.
Smaller turning radius, enabling escape from more extreme road conditions. Independent torque control of the four motors allows the wheels on the left and right sides to move in opposite directions, achieving a spin around the vehicle's center. In contrast, spins based on fuel four-wheel drive or electric four-wheel drive structures (also known as compass turns or pivot turns) are achieved by locking certain wheels, resulting in a larger turning radius than those based on quad-motor systems. If needed, such as during parallel parking, Xiaomi's Smart Chassis can also switch from the default spin-in-place mode to the compass turn mode.