This study proposes a double-vector control strategy for permanent magnet synchronous linear motors (PMSLMs) in vehicle suspension systems, achieving a 70% reduction in sprung mass vibration, 20% faster response times, and 5.7% lower energy consumption compared to single-vector control, paving the way for smoother, more efficient suspension systems in electric and autonomous vehicles.
Let’s face it—nobody enjoys a bumpy car ride. Whether you’re navigating potholes or cruising on a highway, your vehicle’s suspension system works tirelessly to keep you comfortable. But traditional hydraulic and pneumatic systems, while widely used, have their flaws: slow response times, high energy consumption, and complex mechanics.
Enter linear motors —a game-changing technology promising smoother rides, faster adjustments, and energy savings. A recent breakthrough by researchers Cheng Wang and Jialing Yao from Nanjing Forestry University takes this a step further with a double-vector control strategy for permanent magnet synchronous linear motors (PMSLMs). Let’s dive into how this innovation could transform vehicle suspension systems!
Today’s vehicles rely on hydraulic or pneumatic systems to adjust height and absorb shocks. While they’ve been the go-to for decades, they come with three major drawbacks:
Linear motors, which generate motion in a straight line (instead of rotational), offer a sleeker alternative. But they’ve faced challenges too—like thrust fluctuations and complex control algorithms. That’s where Wang and Yao’s research shines!
The researchers designed a flat rectangular slot structure for the PMSLM. Think of it as a motor with grooves optimized for easy installation and high thrust—even at low currents.
Key Features:
Simulations confirmed the design’s efficiency, with magnetic flux density staying below 1.8 T—a gold standard for avoiding saturation.
Traditional control methods for linear motors use a single voltage vector per cycle, leading to jerky movements and energy waste. The new double-vector control strategy refines this by:
Two-Stage Optimization:
This dual-step process reduces thrust ripples and improves accuracy, much like using two hands instead of one to balance a scale.
How It Works:
The researchers integrated their motor and control strategy into a multi-layer controller :
The team tested their system under various conditions:
Raising the vehicle 0.1 m at 20 m/s on a bumpy Class B road.
Repeated tests at 30 m/s and on rougher Class C roads showed similar gains—75% less vibration and consistent response times.
This research isn’t just about luxury—it’s a leap toward sustainable, safer transportation:
This work proves that combining smart motor design with advanced control strategies can overcome longstanding challenges in vehicle suspension. While real-world testing is next, the simulations are a clear sign of progress.
Permanent Magnet Synchronous Linear Motor (PMSLM) - A motor that moves in a straight line (not rotation) using magnets for precise, efficient motion. The study uses a flat rectangular slot PMSLM to lift/lower vehicle height with high thrust (1500 N at just 4A current!).
Voltage vectors - represent the different possible voltage outputs generated by an inverter to drive a motor. In a two-level inverter system, these vectors correspond to specific switching states of the power transistors, creating distinct voltage patterns (magnitude and direction) that control the motor’s current and motion.
Double-Vector Control - A control method that selects two voltage vectors per cycle (instead of one) to reduce errors and improve motor performance. This strategy cut vibration by 70% and boosted response speed by 20% compared to single-vector control.
Finite-Set Model Predictive Control (FSMPC) - A control algorithm that predicts future motor behavior to pick the best voltage inputs. FSMPC was modified with double-vector control to optimize voltage selection, reducing thrust fluctuations.
Vehicle Suspension System - The system that absorbs shocks and keeps your ride smooth (e.g., hydraulic/pneumatic systems). Traditional hydraulic suspensions are compared to the new linear motor-based suspension for faster, energy-efficient height adjustments. - More about this concept in the article "Revolutionizing Railway Comfort: A Game-Changing Suspension System for Smoother Rides".
Thrust Ripple - Unwanted fluctuations in a motor’s force output, causing jerky motion. The flat rectangular slot motor design minimized thrust ripple, ensuring smoother lifts.
Magnetic Saturation - When a material can’t handle more magnetic flux (like overloading a sponge with water). The motor’s design kept magnetic flux density below 1.8 T to avoid saturation.
PI Controller - A feedback loop that adjusts inputs (like current) to hit a target (e.g., vehicle height). A PI controller converted the target height (0.1 m) into current signals for the motor. - More about this concept in the article "Floating Through Curves: Magnetic Levitation for Pipe Maintenance".
Active Suspension - A suspension system that actively adjusts to road conditions (vs. passive systems). The linear motor + double-vector control creates an active suspension for real-time height control.
Electromagnetic Thrust - Force generated by electromagnetic fields in motors. The motor produced 3000 N thrust at 8A, enabling quick vehicle height adjustments.
Closed-Loop Control - A system that uses feedback (e.g., height sensors) to self-correct. The motor’s thrust was fed back into the vehicle model to maintain the target height.
From: Nanjing Forestry University.
