Hydrostatic Pump Control for Smooth Load-Dependent Deceleration
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Solution Overview
Problem
Existing hydrostatic drive systems face challenges in regulating pump inclination angle and motor speed, leading to indirect control and instability during acceleration and deceleration, particularly in load-dependent conditions, requiring complex control systems or additional components.
Innovation Solution
A method that regulates the hydrostatic drive system by calculating a control speed based on both desired and actual drive motor speeds, using a regulation unit to adjust the hydraulic pump's inclination angle, allowing for direct user input and smooth transitions between drive and deceleration conditions without additional components or complex systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EDA control is used to regulate the hydraulic pump based on drive motor speed, then load-dependent smooth deceleration is achieved, but indirect control causes delays and inability to deliver speed during acceleration from stationary condition
Solution Approach 1:
The control system calculates a preliminary control speed value based on the desired speed before actual motor response occurs. This preliminary calculation allows the pump inclination angle to be adjusted in advance, compensating for the inherent delays in the hydraulic system and enabling faster acceleration response from stationary conditions.
Solution Approach 2:
The system continuously monitors the actual drive motor speed and uses this feedback to dynamically adjust the control speed calculation. By comparing desired speed with actual speed in real-time, the control system optimizes the pump regulation to eliminate delays and improve responsiveness during acceleration while maintaining smooth deceleration characteristics.
2Speed
If DAC control is used to regulate the drive system based on desired drive motor speed, then direct speed specification is achieved, but the system becomes non-load-dependent and loses load-dependent performance advantages
Solution Approach 1:
The control method merges the advantages of both EDA and DAC control systems by combining direct speed specification with load-dependent adaptation. The control speed is calculated by integrating both the desired speed input and the actual motor speed feedback, creating a hybrid control approach that provides direct speed control while maintaining sensitivity to load conditions for optimal performance.
3Adaptability or versatility
If DRC control is used to regulate the pump according to the lowest of current and desired speed, then load-dependent adaptation is achieved, but smooth deceleration advantage is lost when idle speed is zero
Solution Approach 1:
The control system dynamically changes the control parameter (control speed) based on operating conditions. Instead of simply using the lowest of desired and actual speed, the system calculates an optimized control speed that maintains load-dependent adaptation while ensuring smooth deceleration performance even when idle speed is zero, thereby resolving the contradiction between adaptability and deceleration reliability.
Data Source
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AI summary
The present invention relates to a method for regulating a hydrostatic drive system, wherein the said hydrostatic drive system comprises a hydraulic pump (12), whose rotation is guaranteed by a drive motor, and at least one hydraulic motor connected in a closed loop to the said hydraulic pump (12), wherein the said hydraulic pump (12) features a regulation unit (4) for regulating displacement of the said hydraulic pump, wherein the said displacement can be regulated by adjusting an inclination angle (αpmp) of an inclined member (2), wherein the said hydrostatic drive system is configured to regulate the said inclined member (2) based on a control speed of the said drive motor, wherein the said drive motor is regulated based on a signal from an input unit in the said hydrostatic drive system, the said input unit being configured so as to be able to receive a command from a user of the said drive system, the said method being configured comprising the following steps: a. Detecting a signal from the said user by means of the said input unit; b. Detecting a desired speed of the said drive motor based on the said signal detected in step a., and detecting an actual speed of the said drive motor; c. Calculating a value of the said drive motor control speed to use to regulate the hydraulic pump (12) on the basis of the said signal from the said user detected in the said step a., and likewise a value of the said desired speed and a value of the said actual speed; d. Regulating the said hydraulic pump based on the said control speed calculated in the said step c.