Hydraulic Spool Control with Motor Feedback for Vibration Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulic control devices for slewing gears in cranes and excavators exhibit detrimental PT-2 behavior, leading to vibrations in the hydraulic fluid volume flow, which are transmitted as torsional vibrations, making the consumer difficult to control and potentially damaging.
Innovation Solution
A control device where the load-pressure-dependent force on the control spool is transmitted to an electric motor controller, which detects and dampens these vibrations by evaluating the force, eliminating the need for additional pressure sensors and incorporating a brushless DC motor with sensorless commutation and a rotation angle sensor to effectively manage the load pressure and position of the control spool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control spool is opened or closed abruptly to control the hydraulic motor, then the control response is improved, but vibrations are generated in the hydraulic fluid volume flow which are transmitted to the consumer as torsional vibrations
Solution Approach 1:
The patent implements feedback control by using the motor controller to detect rotor position changes caused by load-pressure-dependent forces on the control spool. The controller continuously monitors these changes and adjusts the motor actuation to compensate for vibrations, creating a closed-loop system that reduces harmful vibrations while maintaining fast response.
Solution Approach 2:
The motor acts as an intermediary between the control spool and the hydraulic system. Instead of directly actuating the control spool with a traditional hydraulic pilot system, the motor provides controlled actuation while simultaneously sensing load-pressure forces, thereby mediating the control action to reduce vibrations before they propagate to the consumer.
2Measurement precision
If pressure sensors are installed to measure load pressure for vibration compensation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The motor controller serves dual functions: it controls the motor actuator and simultaneously detects load-pressure-dependent forces through rotor position sensing. This self-service approach eliminates the need for separate pressure sensors, as the existing motor control system provides both actuation and measurement capabilities.
Solution Approach 2:
The motor controller is designed to perform multiple functions: motor control, rotor position detection, and load-pressure force detection. This multi-functionality allows the system to achieve precise load pressure measurement without adding dedicated pressure sensing components, thereby reducing overall device complexity.
3Device complexity
If traditional control devices are used without vibration compensation, then device complexity is reduced, but the consumer becomes difficult to control and may be damaged
Solution Approach 1:
The feedback mechanism uses rotor position sensing to detect vibrations at their source (the control spool) and enables real-time compensation by adjusting motor actuation. This feedback loop prevents vibrations from propagating to the consumer, significantly improving control reliability while maintaining relatively simple device architecture.
Solution Approach 2:
The system applies preliminary anti-action by detecting load-pressure-dependent forces before they fully develop into harmful vibrations. The motor controller proactively adjusts motor actuation to counteract emerging vibrations, preventing them from reaching the consumer rather than reacting after damage occurs.
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 solution significantly reduces PT-2 behavior, effectively dampens vibrations, extends service life, and reduces costs by eliminating the need for additional components, while ensuring reliable detection of the rotor position even at low speeds, thus improving control precision and durability.
Implementation Method 1
the load pressure exerts a force on the control spool. That force is transmitted to the motor
Implementation Method 2
the detection of a rotor position, corresponding to the load-pressure-dependent force acting on the control spool, of the DC motor by a counter-voltage applied to the coils of a stator
Implementation Method 3
By the magnetic field of the rotor, the current flow through the coils can be changed as a result of the change in the load-pressure-dependent force
Data Source
AI summary
A control device, for a hydraulic consumer (22) and susceptible to vibrations, includes a valve (24) having a control spool (40) controllable by an actuating device (46). The valve (24) has a pressure supply port (P), to which a pressure compensator valve can be connected, which can be supplied with pressure fluid from a pressure supply device. The actuating device (46) has a motor (74). A load-pressure-dependent force on the control spool (40) can be generated by a control device (66). That force at the control spool (40) acts on an electronic motor controller (208) of the DC motor (74), which detects a change of the force and acts as a damping of the vibrations of the consumer (22) against this change of force.