2020 Lexus RX: three levels of active suspension control

One of the hallmark qualities of the Lexus RX is its comfortable and reassuring ride quality. The 2020 Lexus RX helps to maintain this characteristic with the availability of a world-first suspension combination.

It’s a multi-faceted system that actively controls the suspension’s attitude as it moves both up and down and as forces are exerted across the car, helping to ensure maximum comfort in all road conditions. The result is a driving experience that offers the sensation of being stabilised in mid-air, as if the RX is hooked in the sky while navigating a bend.

Control level one: Adaptive Variable Suspension

The active chassis control of RX begins with our Adaptive Variable Suspension system. Initially introduced in the flagship LC coupe, this technology is now a standard feature in RX F Sport and RX Takumi grade models. It constantly ‘reads’ the road and reacts to what it finds by selecting the optimal damper setting for prevailing conditions from a menu of 650 different rates. These are immediately applied through actuators integrated into the lower housing of each shock absorber.

The Adaptive Variable Suspension system actuator is integrated into the lower shock absorber housing (front shock absorber shown)

In addition to reacting instantaneously to isolate passengers from rough surfaces, AVS is programmed to automatically reduce damping force at low speed and increase it at high speed to maintain optimum comfort and control. It also adapts damping force to combat body roll and pitching motion.

Control level two: Active Stabiliser Suspension

The next two levels of chassis control are dedicated to RX F Sport grade models and applied as a single optional extra – Active Stabiliser Suspension. At the heart of this electric system is a powerful, rotary actuator that applies precise levels of torque through each side of the stabiliser, or anti-roll bar.

The front Active Stabiliser Suspension actuator is located above the rear of the front crossmember and applies torque to each end of the stabiliser independently

Traditional stabiliser set-ups use a cylindrical bar to physically connect both sides of the suspension system and help correct a vehicle’s natural tendency to roll when cornering. When one side experiences lateral force, the bar acts as a torsion spring to distribute this force more equally across the axle. It creates a levelling effect that keeps the vehicle body nearer the horizontal. However, the installation of such a solid connection between both sides of the vehicle’s suspension means that sudden jolts experienced on one side are often transmitted across to the other.

To help solve this issue, the Active Stabiliser Suspension system splits the stabiliser in two and houses each half inside a powerful actuator. The electric motors within this actuator then apply the necessary torque to each side independently to create an enhanced levelling effect without deteriorating ride comfort – outcomes that in normal circumstances are mutually exclusive.

Control level three: Roll Skyhook Control

In Eco, Normal and Sport S modes, the Active Stabiliser Suspension system focuses on suppressing body roll, creating a composed, natural and comfortable vehicle posture when cornering. However, turning the Drive Mode Select dial to Sport S+ enhances the system to operate with Roll Skyhook Control.

The rear Active Stabiliser Suspension actuator is located behind the rear crossmember

While the active stabilisers are excellent at cancelling out body roll, stability can still be affected when you are driving over bumpy surfaces or hit a pothole. Roll Skyhook Control therefore adds a valuable new dimension to the system by using a vertical G-force sensor to measure such sudden movements. This data allows the system to quantify the impact force and instantly suppress it by supplying a corresponding counterforce through the actuator on the stabiliser. The result is a sensation of being stabilised in mid-air, as if the RX is hooked in the sky.

This combination of all three active chassis technologies is a world-first achievement for Lexus. It not only contributes to the responsiveness and agility of the 2020 Lexus RX, but it also improves passenger comfort and maintains each individual’s line of sight and body position when travelling over uneven road surfaces.

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