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.
Source: Wang, C.; Yao, J. Vehicle Height Lifting Strategy Based on Double-Vector Control of Permanent Magnet Synchronous Linear Motor. Electronics 2025, 14, 1515. https://doi.org/10.3390/electronics14081515
From: Nanjing Forestry University.
