Implement descending stability control method and system and tractor

An implement descending stability control method, using an implement descending stability control system, wherein the implement descending stability control system comprises a main pump, an outlet of the main pump is communicated with an inlet of a main overflow valve, an inlet of a constant-difference overflow valve and an inlet of an implement control valve;

• wherein an oil outlet of the implement control valve is connected with a spring cavity of the constant-difference overflow valve through a steady-state throttle valve and is communicated with an inlet of a switching valve;
• wherein an oil outlet of the switching valve is connected with a rodless cavity of a suspension cylinder in a suspension mechanism, the rodless cavity of the suspension cylinder is communicated with an inlet of a descending valve, and a rod cavity of the suspension cylinder is connected with an inlet of a secondary overflow valve;
• wherein a position sensor, a force sensor for acquiring load information of the suspension mechanism, a descending knob, a target position setting knob and a descending speed setting knob are electrically connected with an input terminal of a controller, and an output terminal of the controller is electrically connected with a solenoid valve of the implement control valve, a solenoid valve of the descending valve, and a solenoid valve of the switching valve;
• the implement descending stability control method comprising:
• inputting, by the descending knob, a descending instruction to the controller;
• reading, by the controller, load information of the suspension mechanism acquired by the force sensor and comparing the load information with a set value;
• when the load information of the suspension mechanism acquired by the force sensor is less than the set value, selecting a no-load or light-load mode by the controller to control an implement to descend;
• and
• when the load information of the suspension mechanism acquired by the force sensor is greater than or equal to the set value, selecting a medium-load/heavy-load mode by the controller to control the implement to descend.