To achieve this functionality, REE’s four-corner demonstrator includes a control system developed by Sherf using Trio’s controllers, servos, and the Motion-iX engineering design platform.

UK motion control specialist, Trio Motion Technology, has provided an all-wheel steering control system for a four-corner electric vehicle (EV) demonstrator. Trio partner Sherf Motion Technologies has developed the system for EV manufacturer REE Automotive to showcase independent corner control, including steering and suspension, for each wheel on REE's flat EV chassis.

REE's EV four-corner demonstrator made its debut at CES 2022 Las Vegas, the world's largest technology show, and is now on display at an executive business center in Herzliya, Israel, where REE is headquartered.
REE's electric vehicle chassis includes independent control for each of the four wheels, including steering, suspension, powertrain, and braking. This design enables a completely flat chassis that maximizes room for people, cargo, and batteries. The modular design of REE's chassis can be integrated with body styles ranging from cars to buses, supporting EV class 1 to 6.
To display these capabilities, REE's four-corner demonstrator needed to show all-wheel independent steering. This increases maneuverability as well as safety if one or more wheels reduce traction from a loose or slippery surface. The four-corner demonstrator was also required to show the flexibility of REE's modular design capability that enables a wide range of vehicle sizes.
To achieve this functionality, REE's four-corner demonstrator includes a control system developed by Sherf using Trio's controllers, servos, and the Motion-iX engineering design platform. Steering is coordinated by a Trio Flex-6 Nano Motion Coordinator. Providing independent steering of each wheel, the Trio Flex-6 Nano coordinates all 15 axes. Independent control is provided for steering angle and camber, as well as for shock absorber suspension simulation. Each wheel includes three Trio DX4 servo drives and Trio MX servo motors. The motion calculation formulae are based on Ackermann's theory and help maintain optimum traction and steering geometry in motion.
An additional axis also allows REE's EV platform to resize in width and length, showing the flexibility of the modular design. The demonstration can move each wheel longitudinally and laterally, thanks to a Trio-controlled XY system.
Trio's pocket-sized Flex-6 Nano Motion Coordinator was selected for its compact dimensions and multi-axis synchronization capability. A Flex-6 Nano can control up to 64 axes with high-speed EtherCAT update rates as low as 125μs depending on axis count. Combined with Trio's DX4 servo drive and MX servo motor package, this enables seamless motion coordination, required for fast development and long-term reliability.
Independent steering and suspension control for REE's four-corner demonstration was developed by Israel's Sherf Motion Technologies, involved at outset to design the system based on Trio's controllers and servos.
"The Motion Coordinators enabled us to develop the accurate control required for REE's innovative EV four-corner demonstration because of their mathematical capabilities and advanced features," says Moshe Sherf, CEO, Sherf Motion Technologies. "Design flexibility was important for the project and Trio's easy-to-use development platform enabled fast changes to be made, with straightforward connectivity providing communication with REE's vehicle control unit."

About Trio Motion Technology
Trio Motion Technology was founded in 1987 as a manufacturer of motion controllers. Today the range, branded Motion Coordinators, can control up to 128 axes of servo, stepper and piezo motors as well as hydraulic systems. Trio's expertise of motion programming is based within its Motion-iX technology. Launch of the new servo drive and motor package now develops Trio's offering into a motion solution in addition to providing motion controllers for automation vendors and system integrators.
The company headquarters is based in Tewkesbury, Gloucestershire, UK, which also comprises its primary research and development hub. Additional R&D facilities are located in Italy, Bulgaria, and also China, where Trio's products are assembled. Application development teams are located in the UK, USA, Italy, India and China, and a global sales network comprises over 100 partners.
In 2017 Trio was acquired by the Estun Group, which is supporting Trio in its growth with assistance through shared facilities and R&D as well as financial backing. Trio has exceeded 15% growth year on year since the acquisition. In addition to the primary global markets, a significant proportion of Trio's business is in China where the company's motion control capability has enabled Estun to become a major player in the China automation market. Despite the presence of the Estun brand, motion control products in China carry Trio branding.
For more information, visit www.triomotion.com