Distributed Electrohydraulic Circuit for Manipulator Response Control
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Solution Overview
Problem
Current electrohydraulic control circuits for large manipulators, such as those in truck-mounted concrete pumps, face issues with delayed response, susceptibility to line breakage, limited adaptability, and inability to implement highly dynamic control strategies due to central control block limitations and inadequate pressure sensing.
Innovation Solution
An electrohydraulic control circuit with an electronic control device integrated close to the actuator, featuring a proportional valve and pressure sensors to monitor forces and pressures, allowing for flexible adaptation and improved response, and incorporating an emergency circuit for enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a central control block is used to control hydraulic actuators, then individual segment control is achieved, but line lengths become very long (up to 70m) causing delayed response and increased susceptibility to line breakage
Solution Approach 1:
The control system is segmented into distributed electronic control devices, each associated with specific hydraulic actuators and segments. This segmentation eliminates the need for long centralized hydraulic lines while maintaining individual segment control capability, thereby improving response time and reducing line breakage risk
Solution Approach 2:
The patent replaces the traditional centralized electro-hydraulic control system with a distributed electronic control system. Electronic control signals replace long hydraulic control lines, eliminating mechanical line breakage risks and reducing response delays while maintaining actuator control functionality
2Reliability
If lowering brake valves are used to prevent unintentional segment lowering, then safety is improved, but response behavior deteriorates due to additional delays and frequent opening/closing at slow travel speeds
Solution Approach 1:
The patent replaces mechanical lowering brake valves with an electronic control system that uses electronic control devices and electronic braking control. This substitution eliminates the mechanical valve opening/closing delays while maintaining safety functions, thereby improving response behavior at slow travel speeds
Solution Approach 2:
The electronic control system incorporates feedback mechanisms that continuously monitor segment position and actuator state, enabling proactive control that prevents unintentional lowering without requiring frequent mechanical valve interventions. This feedback-based control reduces response delays while maintaining safety
3Productivity
If pressure sensors are used to detect segment vibrations for damping control, then vibration detection is achieved, but vibrations acting on stationary hydraulic cylinders cannot be detected and measurement precision is reduced
Solution Approach 1:
The patent replaces mechanical pressure sensor-based vibration detection with electronic sensors (such as accelerometers or gyroscopes) that directly measure segment motion. This substitution enables accurate detection of actual segment vibrations while filtering out noise from stationary hydraulic cylinders, thereby improving measurement precision for vibration damping control
4Device complexity
If electrohydraulic control circuits are implemented exclusively in hardware, then system simplicity is maintained, but flexibility and adaptability are lost
Solution Approach 1:
The patent replaces exclusive hardware-based electrohydraulic control with a distributed electronic control system that uses software programs stored in memory. This substitution provides flexibility and adaptability through software configuration while maintaining system simplicity through modular electronic control devices, thereby resolving the contradiction between complexity and adaptability
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 provides a robust, flexible, and efficient control system with reduced line lengths, improved response times, and enhanced reliability, enabling precise control of actuator force and speed, and adaptive pressure management.
Implementation Method 1
a first sensor means (4.1) arranged on the segment (5.3) and supplying a first measurement signal (ε)—in particular a deformation signal—corresponding to a dynamic state of the segment (5.3)
Implementation Method 2
a first proportional valve (2.4), with which a pressure difference can be applied to working lines (A1, A2) of an actuator (5.6) assigned to the segment (5.3)
Implementation Method 3
a first electronic control device (ECU), which is set up to control the proportional valve (2.4) on the basis of the first measurement signal (ε) and a second measurement signal (s) corresponding to a position of the actuator (5.6)
Implementation Method 4
with which a pressure difference can be applied to working lines (A1, A2) of an actuator (5.6) assigned to the segment (5.3), in particular to a piston of the actuator (5.6)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to an electrohydraulic control circuit for controlling a hydraulically actuated control element (5.6), by means of which a segment (5.3) of a manipulator, in particular of a large manipulator for self-propelled concrete pumps, can be adjusted in regard to the orientation of said manipulator, characterised by an electrically controlled first valve (2.4), which is connected to hydraulic working lines of the control element (5.6) for the control of the control element, and leakage-free shut-off valves (2.5, 2.6), which are provided in the working lines of the control element (5.6) and are arranged on the control element (5.6) or the segment (5.3) associated with said control element (5.6) and can be blocked for the normal operation of the control element (5.6), the blocking of the shut-off valves (2.5, 2.6) being controlled by an electronic control unit (ECU) that is separate from the first valve (2.4) and from the shut-off valves (2.5, 2.6).