Synchronous control device for hydraulic cylinder and control method thereof

Abstract

The invention relates to a synchronous control device for a hydraulic cylinder and a control method thereof. The device comprises a device body, an active hydraulic cylinder, n driven hydraulic cylinders, n+1 proportioning valves and n+1 hydraulic control one-way valves, wherein the active hydraulic cylinder is connected with all driven hydraulic cylinders and the device body and synchronously drives all the driven hydraulic cylinders and the device body; the active hydraulic cylinder and all the driven hydraulic cylinders are connected with a proportioning valve respectively and controlled by the proportioning valves; and each hydraulic control one-way valve is arranged on two pipelines behind each proportioning valve.

Description

technical field [0001] The invention relates to the technical field of hydraulic transmission control, in particular to a hydraulic cylinder synchronous control device and a control method thereof. Background technique [0002] In industrial production, it is common to use two or more hydraulic cylinders to synchronously drive one device or multiple independent devices. In order to realize the synchronization function between two or more hydraulic cylinders, the following two synchronization methods are usually used: Control mode: One is a pure hydraulic circuit mode, that is, a group of hydraulic cylinders is controlled by the same common reversing valve, and the synchronization between each hydraulic cylinder can be fine-tuned through the throttle valve installed on the branch of each hydraulic cylinder's inlet and outlet oil pipes ; The other is the electronic control method, which requires each hydraulic cylinder to have a position sensor (such as a magnetostrictive posi...

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Problems solved by technology

[0003] For the hydraulic cylinder synchronous control mode of the pure hydraulic circuit mode mentioned above, it should be said that a hydraulic cylinder synchronous control mode with low synchronization accuracy and synchronization stability requires frequent adjustments in the actual use of the hydraulic cylinder. Throttle valve, otherwise the relative synchronous movement between hydraulic cylinders cannot be obtained

For the hydraulic cylinder synchronous control of the above-mentioned electronic control method, although the speed deviation correction of the master-slave hydraulic cylinder is added in the speed closed-loop control of the slave hydraulic cylinder, the dynamic synchronization accuracy and robustness of this hydraulic synchronous control method The performance is not very high, and there are also the following problems in actual use: (1) When the slave hydraulic cylinder has a certain internal leakage, the slave hydraulic cylinder may not be synchronized with the active hydraulic cylinder; (2) When the slave hydraulic cylinder When the hydraulic cylinder is severely blocked during the movement process, the slave hydraulic cylinder will not be synchronized with the active hydraulic cylinder; (3) In the case of the rapid movement of the master and slave hydraulic cylinders, that is, the large opening of the proportional regulating valve of the master and slave hydraulic cylinders Under the condition that the master-slave speed deviation correction effect of the slave hydraulic cylinder is limited, that is, the opening degree of the proportional regulating valve of the slave hydraulic cylinder is already at the maximum opening degree, in this case, once the slave hydraulic cylinder lags behind the active The hydraulic cylinder and the slave hydraulic cylinder will not be able to accelerate to follow its active hydraulic cylinder, so that the dynamic asynchrony of the master and slave hydraulic cylinders will inevitably occur; (4) Considering the execution cycle of the hydraulic synchronization control program and the response time of the proportional control valve, this This method only corrects the speed deviation of the master and slave hydraulic cylinders for the slave hydraulic cylinders, and cannot guarantee the dynamic synchronization of the master and slave hydraulic cylinders

Aiming at the problem of internal leakage of hydraulic cylinders, in actual production, this is a common phenomenon. For equipment driven by a single hydraulic cylinder, a certain amount of internal leakage of the hydraulic cylinder may not have much impact on the operation and process control of the equipment. However, for equipment synchronously driven by multiple hydraulic cylinders, especially for large-scale equipment synchronously driven by large-scale hydraulic cylinders, if the previous hydraulic cylinder synchronous control scheme is adopted, once a certain amount of internal If there is internal leakage, the hydraulic cylinder with internal leakage will not be able to move synchronously with other hydraulic cylinders, so that the safe and stable movement of the equipment cannot be guaranteed. In this case, only by stopping production and replacing the hydraulic cylinder with internal leakage can the normal operation of the equipment be restored.

However, for a large-scale hydraulic cylinder, online replacement may usually require a long downtime (such as more than ten hours), which will inevitably have a serious impact on the stability of production

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