Stability control of suspended monorail vehicles based on PID and quadratic programming allocation

Area of Science:

• Transportation Engineering
• Control Systems Engineering
• Vehicle Dynamics

Background:

• Suspended monorail vehicles face coupled lateral-vertical vibrations due to track irregularities and crosswinds.
• These vibrations negatively impact operational stability and passenger comfort.
• Existing control methods may not adequately address actuator constraints.

Purpose of the Study:

• To develop an actuator-constrained hierarchical control framework for suspended monorail vehicles.
• To improve lateral-vertical stability and passenger comfort under dynamic disturbances.
• To propose a novel vehicle-specific constrained control-allocation procedure.

Main Methods:

• A high-fidelity vehicle dynamics model was developed and calibrated with measured data.
• Sobol sensitivity analysis determined optimal actuator configurations.
• A fuzzy self-tuning PID controller (inner loop) generated virtual commands, allocated by Quadratic Programming (outer loop) respecting actuator constraints.
• Comparison with a linear-quadratic regulator (LQR)-QP benchmark controller.

Main Results:

• The fuzzy self-tuning PID-QP controller outperformed the benchmark, reducing lateral and vertical acceleration RMS values by 21.15% and 20.80%, respectively.
• Acceleration peaks were reduced by up to 32.42%.
• Lateral and vertical stability indices showed significant improvements (RMS reduction of ~6.7%).

Conclusions:

• The proposed hierarchical cooperative control framework effectively enhances suspended monorail vehicle stability.
• The control strategy successfully manages coupled lateral-vertical vibrations within actuator amplitude constraints.
• This approach offers a promising solution for improving the safety and comfort of suspended monorail systems.