Multi-Servo Subgrade Loading for Principal Stress Axis Rotation
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Solution Overview
Problem
Existing loading simulation systems for subgrade or foundation dynamic response struggle with simulating principal stress axes rotation, are limited to single application scenarios, and face challenges in controlling nonlinear systems with variable parameters, making accurate modeling difficult.
Innovation Solution
A system utilizing a multi-servo channel with dynamic and static actuators, combined with a deep reinforcement learning (DRL) control method, to simulate principal stress axes rotation and adapt to various traffic loads, enabling accurate simulation of dynamic stress on subgrade or foundation structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distributed time sequence loading of vertical excitation forces is used to simulate principal stress axes rotation, then the simulation effect is improved, but the system complexity and time consumption increase due to requiring complete track-subgrade-foundation structure
Solution Approach 1:
The patent extracts the essential function of simulating principal stress axes rotation from the complete track-subgrade-foundation structure. By using a simplified loading device with multiple actuators that can directly apply controlled forces to the subgrade or foundation, the system removes the need for rails and complete track structure while retaining the core simulation capability through multi-channel servo control of actuator forces
Solution Approach 2:
The patent creates a simplified copy of the complex track-subgrade-foundation system by using a dedicated loading device that replicates the essential loading characteristics. The multi-actuator system copies the stress rotation effect without requiring the actual track structure, achieving the same simulation purpose with reduced complexity
2Power
If existing dynamic loading equipment is used to simulate train load, then the loading function is achieved, but the adaptability to different traffic scenarios (highway, airport, railway) is limited
Solution Approach 1:
The patent designs a loading device with multiple independently controllable actuators that can generate various loading patterns. By controlling the magnitude, direction, and timing of forces from multiple actuators, the system can simulate different traffic loads (train, highway, aircraft) and stress conditions, making a single device applicable to multiple transportation scenarios without requiring separate specialized equipment for each
3Ease of operation
If PID controller is used for multi-cylinder dynamic and static cooperative loading, then the control implementation is simplified, but the control precision and response speed for nonlinear complex systems are insufficient
Solution Approach 1:
The patent implements a closed-loop feedback control system where sensors monitor the actual position, force, and deformation of the subgrade or foundation in real-time. This feedback information is fed back to the control system, which continuously adjusts the actuator outputs to maintain precise control despite nonlinearities and external disturbances, achieving high precision without oversimplifying the control approach
Data Source
AI summary
A system for loading dynamic stress on subgrade or foundation based on multi-servo channel and a control method thereof. The system comprises: connecting plate; five dynamic actuators are hinged between connecting frame and the connecting plate; four of them form 4-RPR parallel mechanism, another one is arranged in middle of the 4-RPR parallel mechanism; loading part is mounted at center under the connecting frame; and restraining plate is arranged under the loading part and freely contacts with the loading part; four static actuators are arranged between the restraining plate and the connecting plate; wherein, the static actuators and dynamic actuators are dynamic-static cooperative controlled through multi-servo channel, to simulate principal stress axes rotation effect of a soil body of subgrade or foundation The system can realize the principal stress axes rotation effect in the subgrade or foundation through dynamic-static cooperative loading and can simulate different traffic load forms.