Bi-directional Linear Pump Zero Point Setting for Active Suspension
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Solution Overview
Problem
Existing active suspension systems for vehicles require high-priced proportional control valves and hydraulic pumps, leading to inefficiencies in fuel efficiency and engine output, and lack a method to effectively set the zero point of bi-directional linear pumps, making it difficult to manage control inputs and detect disturbances.
Innovation Solution
A method for setting the zero point of a bi-directional linear pump involves controlling valves using an electronic control unit to move the piston to MAX and MIN Stroke positions, calculating approximate positions, and determining pump normalcy by comparing these positions, allowing for effective control and fail-state detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a proportional control valve and hydraulic pump are used in the active suspension system, then the system can effectively control fluid supply to actuators, but the system cost increases and fuel efficiency deteriorates
Solution Approach 1:
The patent replaces the traditional proportional control valve with an electrically controllable valve that opens or closes based on binary control signals from the ECU. This substitution eliminates the need for high-precision mechanical proportional valves, reducing system cost while maintaining adequate control capability for the active suspension application.
Solution Approach 2:
The hydraulic pump operates intermittently rather than continuously. The ECU controls the pump to operate only when fluid supply to actuators is required, using periodic on/off cycling based on system demands. This reduces energy consumption and improves fuel efficiency compared to constant pump operation.
2Stress or pressure
If the hydraulic pump is constantly driven to generate high pressure, then sufficient fluid pressure is available for actuator operation, but engine output is reduced and fuel efficiency deteriorates
Solution Approach 1:
The hydraulic pump operates intermittently rather than continuously. The ECU controls the pump to operate only when fluid supply to actuators is required, using periodic on/off cycling based on system demands. This reduces energy consumption and improves fuel efficiency compared to constant pump operation.
Solution Approach 2:
The system uses the vehicle's existing hydraulic infrastructure (power steering pump, brake hydraulic system) to provide fluid pressure for the active suspension. The pump leverages the vehicle's existing powertrain output rather than requiring a dedicated high-power pump, effectively using already-available energy resources.
3Productivity
If a bi-directional linear pump is used without zero point setting, then the pump can supply fluid to actuators, but effective response to control inputs becomes difficult
Solution Approach 1:
The system performs a zero point setting operation before normal actuator control. The ECU commands the pump to move the piston to a predetermined neutral position where equal volumes of fluid are supplied to both sides of the actuator. This preliminary positioning establishes a known reference state, enabling subsequent control inputs to produce predictable and accurate actuator responses.
Solution Approach 2:
The system uses feedback from actuator position sensors to monitor piston position and determine when the zero point has been achieved. The ECU compares actual position feedback with target positions and adjusts pump operation accordingly, ensuring accurate zero point establishment and maintaining proper control response during operation.
Data Source
AI summary
A method of setting a zero point according to one embodiment of the present disclosure relates to a method of setting a zero point of a bi-directional linear pump for an active suspension apparatus supplying fluid to an actuator connected to a coil spring coupled to a wheel of a vehicle, which includes controlling at least one of a first valve disposed between the actuator and the pump and a second valve disposed between the pump and a fluid reservoir by means of an electronic control unit (ECU) in a first Operation, moving a piston disposed inside the pump to one side to move the piston up to a MAX Stroke position of the one side in a second Operation, calculating an approximate MIN Stroke position of the other side of the piston based on the MAX Stroke position of the one end thereof in a third Operation, moving the piston to the other side to move the piston up to a MIN Stroke position in a fourth Operation, comparing the approximate MIN Stroke position of the other side with the MIN Stroke position thereof in a fifth Operation, and determining whether or not the pump is normal in a sixth Operation based on the comparison result.