Hydraulic Actuator Leak Detection Using Rotor Position Feedback
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Solution Overview
Problem
Existing methods for controlling hydrostatic actuators in motor vehicles lack precision and reproducibility, particularly due to wear-related changes in the hydraulic circuit over time, which affects the accurate actuation of components like clutches and transmissions.
Innovation Solution
A method involving an electric motor with a rotor position sensor to detect rotor rotation, set and maintain predetermined pressure in a fluid pump, and determine leakage volume flow, allowing for precise control and monitoring of fluid delivery, thereby accounting for wear and optimizing actuator performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a hydrostatic actuator is used to actuate motor vehicle components, then the actuation speed and force are improved, but wear-related changes in the hydraulic circuit cause loss of precision and reproducibility over time
Solution Approach 1:
The control unit continuously monitors the actual pressure in the hydraulic circuit and compares it with the target pressure, adjusting the motor's rotational speed accordingly to maintain precise control despite wear-related changes in the hydraulic circuit
Solution Approach 2:
The system dynamically adjusts the motor's rotational speed parameter based on actual pressure measurements, allowing the actuator to compensate for wear-related changes in the hydraulic circuit and maintain consistent actuation precision over time
2Speed
If the motor's rotational speed is increased to improve actuation speed, then the actuation response time is reduced, but the leakage volume flow increases
Solution Approach 1:
The control unit uses pressure feedback to adjust motor speed, enabling the system to achieve required actuation speeds while compensating for increased leakage by dynamically optimizing the rotational speed rather than simply increasing it
Solution Approach 2:
The system transitions from static speed control to dynamic speed adjustment, where the motor rotational speed varies continuously based on actual pressure conditions, allowing optimal performance across different operating states and wear levels
3Measurement precision
If pressure sensors and additional sensors are added to monitor hydraulic circuit conditions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses the existing pressure sensor data from the hydraulic circuit control, which is already present for normal operation, to simultaneously detect leakage conditions without requiring additional dedicated sensors
Solution Approach 2:
The pressure sensor serves dual functions: controlling the hydraulic circuit during normal operation and detecting leakage conditions by monitoring pressure maintenance, eliminating the need for separate detection hardware
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
This method enhances the accuracy of fluid delivery and actuator control by determining leakage volume flow, enabling better volume flow management and indicating wear, thus improving the reliability and longevity of motor vehicle components.
Implementation Method 1
rotation of the rotor can be detected by means of a rotor position sensor
Implementation Method 2
The rotor drives the displacer unit, with the result that a fluid is delivered by the displacer unit. The displacer unit has a certain geometric displacement volume per revolution of the rotor
Implementation Method 3
The actuator has at least one drive unit with an electric motor... generating a predetermined pressure at the displacer unit by applying an electrical driving power to the motor
Data Source
AI summary
A method for controlling an actuator includes providing the actuator with a control unit, a drive unit including an electric motor with a stator and a rotor, a rotor position sensor, connected to the control unit, for detecting a rotation of the rotor, and a displacer unit, drivable by the rotation of the rotor, for displacing a fluid. The displacer unit includes a geometric displacement volume per revolution of the rotor. The method also includes generating a predetermined pressure at the displacer unit by applying an electrical driving power to the electric motor, maintaining the predetermined pressure over a predetermined time interval, determining the rotation of the rotor with the rotor position sensor during the predetermined time interval, and determining a leakage volume flow.