Hydraulic Brake Mixed-Mode Control for Dead Zone Elimination
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Solution Overview
Problem
Hydraulic braking systems face challenges during the 'brake fill' period, where pressure-only feedback control systems result in delayed braking action and potential hydraulic pressure overshoot due to inadequate feedback during the transition of the brake piston from the brake actuator to the heat sink, leading to inefficient braking operations.
Innovation Solution
A mixed-mode logic control system that measures the flow rate of hydraulic fluid and adjusts the control signal based on both position and pressure commands, transitioning from position-based to pressure-based control as hydraulic pressure increases, to improve braking system responsiveness and prevent overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pressure-only feedback control is used during brake fill, then the control system is simple, but the braking response is delayed and pressure overshoot occurs
Solution Approach 1:
The patent introduces flow rate feedback during the brake fill period, complementing the existing pressure feedback. The controller receives both pressure feedback signals and flow rate feedback signals, using the flow rate information to detect piston movement and provide timely control adjustment, thereby eliminating the dead zone and preventing pressure overshoot while maintaining system simplicity
Solution Approach 2:
The system performs preliminary detection of piston position through flow rate measurement during the brake fill period, before pressure buildup occurs. This allows the controller to anticipate piston contact with the heat sink and adjust control signals proactively, preventing the delayed response and overshoot associated with pressure-only feedback
2Device complexity
If pressure-only feedback control is used, then the control system is simple, but hydraulic pressure overshoot occurs beyond commanded pressure
Solution Approach 1:
The patent introduces flow rate feedback during the brake fill period, complementing the existing pressure feedback. The controller receives both pressure feedback signals and flow rate feedback signals, using the flow rate information to detect piston movement and provide timely control adjustment, thereby eliminating the dead zone and preventing pressure overshoot while maintaining system simplicity
Solution Approach 2:
The system performs preliminary detection of piston position through flow rate measurement during the brake fill period, before pressure buildup occurs. This allows the controller to anticipate piston contact with the heat sink and adjust control signals proactively, preventing the delayed response and overshoot associated with pressure-only feedback
3Loss of time
If brake fill period is eliminated through better control, then braking response time is improved, but control system complexity increases
Solution Approach 1:
The patent introduces flow rate feedback during the brake fill period, complementing the existing pressure feedback. The controller receives both pressure feedback signals and flow rate feedback signals, using the flow rate information to detect piston movement and provide timely control adjustment, thereby eliminating the dead zone and preventing pressure overshoot while maintaining system simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mixed-mode logic control system reduces the 'dead zone' in braking operations by providing timely feedback and adjusting control signals effectively, ensuring precise and controlled braking force application, thereby enhancing the overall performance and safety of the hydraulic braking system.
Implementation Method 1
a flow detector is provided in the hydraulic braking system configured to measure a flow rate of hydraulic fluid supplied to the brake actuator by the control valve
Implementation Method 2
hydraulic fluid supplied at a hydraulic fluid flow rate based on a magnitude of the control signal from the control assembly to the control valve
Data Source
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AI summary
A braking system including a brake actuator, a control valve, a control assembly, and at least one pressure sensor. The control valve is disposed to direct hydraulic fluid to the brake actuator at a rate corresponding to a magnitude of a control signal. The control assembly includes a mixed-mode control system. The at least one pressure sensor is configured to measure a pressure of the hydraulic fluid to the brake actuator. The control assembly is configured to determine a position of the brake actuator. The mixed-mode control system is configured to determine a position command and a pressure command. The mixed-mode control system is configured to adjust the magnitude of the control signal based on at least one of the position command and the pressure command so as to reposition the brake actuator from a first position to a second position.