SU798251A1 - Control device of shovel digging mechanism - Google Patents

Description

one

 The invention relates to control systems for the digging mechanisms of single-bucket excavators, cranes and a number of other machines with difficult working conditions and is intended to limit the dynamic loads.

A known device comprises a controlled converter system — an engine with a dual-circuit subordinate control system and a dynamic load limiting unit consisting of a constant voltage source, an equalizer element and a key, and allows reducing the dynamic loads on the mechanism l.

However, the process of limiting the load is oscillatory.

A device is known for limiting the dynamic forces in an electric drive of an excavator's working body, including electric valves and an electric drive control system, a current regulator, a force sensor and a load limiting unit consisting of a regenerative current level generator with limited feedback circuit and zener diodes connected in series with the aforementioned driver, which ensures an effective reduction of the dynamic load factor in the electromechanical equipment of the excavator during locking group 2.

However, the process of limiting loads by recovering energy when locking the bucket is oscillatory in nature, which adversely affects the reliability and durability of the equipment and cables.

It is also known a device for controlling the digging mechanism of an excavator, comprising an adjustable drive of the digging mechanism with voltage and current regulators controlled by a 5 converter and a current sensor, force and derivative force sensors, a load limiting unit, an adder and a key element korna circuit and the magnitude of the current of the motor in the brake mode h.

However, the oscillation of the process of limiting the loads is not eliminated. This is due to the fact that the load limiting circuit is the same as in device 2.

Claims (3)

The purpose of the invention is to improve the control and performance of the excavator. The goal is achieved by the fact that the device is equipped with a speed sensor and two diodes, with the sensors of the derivative of the force through a serially connected key element one of the diodes and the adder connected to the current controller, and the control input key through the second diode is connected to the speed sensor. The drawing shows the functional scheme of the device. The device contains a current regulator 1, to the inputs of which a current sensor 2 is connected, a load limiting unit 3 consisting, for example, of a regenerative level generator 4, a current with feedback limiting elements 5, and a voltage regulator. The sensors are connected to 7 force via zener diodes 8 and 9 connected to node 3. Electric motor 10 receives power from converter 11 controlled by system 12 I1 of pulsed-phase control. The motor speed sensor 13 is connected via the first diode 14 to the control input of the key element 15. The force derivative sensor 16 is connected via a serially connected key element 15, the second diode 17 and the cyivMaTOp 18 connected to the current regulator 1 input. The device works as follows. The limitation of the dynamic forces is carried out by transferring the engine / body to the regenerative braking mode. If the force in the mechanism exceeds the stopper value P., the zener diodes 8 and 9 are punctured, and the signal from the sensor 7 is fed into the input of the driver 4, the output of which is the voltage Uf, the value of which is greater than the maximum voltage value Upn may. on the voltage controller 6 code in the lock mode. The polarity of the voltage Uv at the output of the former 4 is opposite to the polarity of the signal of the Urn at the output of the regulator 6 voltage. With UV 7 UpHfYiax, the voltage is completely changed both at the input and at the output of current regulator 1, and the motor goes into regenerative braking mode. The process of braking. Electric drive with recovery. energy into the network occurs as long as the force in the mechanism does not become less than the stopping value. The magnitude of the regenerative current is determined by the difference of the voltages ifrt - irngluch. The magnitude of the stopping current, which is set, is limited by the maximum possible force in the mechanism when operating on the stop. The maximum magnitude of the regenerative motor current is determined by the If of the limited overload capacity due to the switching conditions. The maximum force in an elastic element in the load-limiting mode, determined by the kinetic energy stored in the mechanism, the magnitude of the regenerative current and a number of other parameters, corresponds in time to the transition of the motor speed through zero, during which the signal from the speed sensor 13 passes through the first diode 14 and opens the key element 15. The signal from the sensor 16 is derived from the force through the key element 15, the second diode 17 and the adder 18 is fed to the input of the current regulator. This signal, which is a flexible positive force coupling, eliminates the oscillation of the process of limiting loads caused by the elastic element of the mechanism. The first diode 14 does not pass the signal from the speed sensor in the positive direction of the engine speed. This makes it possible not to delay transients in the drive in operating conditions. As a key element, a semiconductor relay or a series 901 chip of general industrial use is used. The application of the proposed device completely eliminates the oscillation of the process during energy recovery, reduces the duration of the hard locking process by more than 3 times, which increases the productivity and reliability of the excavator. An apparatus for controlling a digging mechanism of an excavator, comprising an adjustable drive of a digging mechanism with current and voltage regulators controlled by a converter and a current sensor, force and derivative force sensors, a load limiting unit, an adder and a key element, the purpose of improving the reliability of control and performance of the excavator, it is equipped with a speed sensor and two diodes, the sensor of the Derivative Force through the serially connected key element, Institute of diodes and an adder connected to the current regulator to a torus, and a control key .The inputs through the second diode is connected to the speed sensor. Sources of information, rintye taken into account in the examination 1. The author's certificate of the USSR 613037, cl. E 02 F 9/20, 1978. 2. Authors certificate of the USSR 442272, cl. E 02 F 9/20, 1974. 3. USSR author's certificate of application No. 2676411/03, l. E 02 F 9/20, 10/12/78 (prototype).