EP1835079B1

EP1835079B1 - Electromechanically controlled excavator and method for controlling the electromechanically controlled excavator.

Info

Publication number: EP1835079B1
Application number: EP06122458A
Authority: EP
Inventors: Qinghua He
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-03-17
Filing date: 2006-10-17
Publication date: 2008-05-07
Anticipated expiration: 2026-10-17
Also published as: EP1835079A1; DE602006001105D1

Description

This invention relates to electromechanically-integrated excavators and methods for controlling the electromechanically-integrated excavators.
Excavators are widely used in the construction industry, and their operation is generally flexible and highly efficient, for example the document DE 199 09 610 A1 (KOMATSU ) discloses an electromechanically-integrated excavator comprising a boom, an arm or a stick, a bucket, a monitoring processor, a data storage, an indicator screen, an audio alarm, and a communication circuit; wherein said monitoring processor is connected with said storage, said indicator screen, said audio alarm, and said communication circuit. Said document also discloses a method for controlling movement of an excavator comprising:

setting a movement trajectory for the excavator, and obtaining a motion sequence of said boom, said stick, and said bucket by utilizing a motion controller, said motion sequence comprising a plurality of sequential position points;
obtaining position information of said boom, said stick, and said bucket by utilizing said angle sensors mounted on said boom, said stick, and said bucket; transmitting said position information via a bus to said motion controller; comparing said position information with said movement trajectory.

However, excavator operation is not without problems, including the required high labor input, the inconvenience of direct human participation under adverse conditions, and the necessity for long training of excavator operators to attain high skills, among others. The improvement of electromechanical integration of excavators is critical for overcoming these drawbacks and for realizing a more automatic and intelligent operation of excavators.
The present invention arose in the context of the above-identified problems. It is one aspect of the present invention to provide an electromechanically-integrated excavator and a method capable of realizing highly precise operation and control, good positioning capability, and lower power consumption.
To achieve the above objective, in accordance with one embodiment of the present invention, there is provided an electro-mechanically integrated excavator, comprising a monitoring processor, a data storage, a watchdog, an indicator screen, an audio alarm, an optoelectronic isolating circuit, a high speed optoelectronic isolating circuit, a counter, a filter, and a communication circuit, wherein the monitoring processor is connected respectively with the storage, the watchdog, the indicator screen, the audio alarm, the revolution counter, the filter, and the communication circuit; the optoelectronic isolating circuit is connected with the filter; and the high speed optoelectronic isolating circuit is connected with the counter.
The excavator of the present invention also comprises a motion controller, a boom angle sensor, a stick or arm angle sensor, and a bucket angle sensor, wherein the outputs of the boom angle sensor, the stick angle sensor, and the bucket angle sensor are connected with the inputs of the motion controller, and the motion controller is connected with the monitoring processor via the communication circuit.
In certain classes of this embodiment, the electromechanically-integrated excavator also comprises a laser emitter rack set near the front portion of the excavator, a laser emitter mounted on the laser emitter rack, and a height detector fixedly mounted on the stick of the excavator, the output of the height detector being connected with the monitoring processor.
In accordance with another aspect of the present invention, the electromechanically-integrated excavator also comprises an energy-saving controller, a mode select switch, and a knob for setting the engine speed or revolutions. The energy saving mode is selected via the mode select switch and a desired engine speed is input via the engine speed setting knob. Both the mode information and the desired revolutions per minute (rpm) are sent to the engine controller, which is a subpart of the energy-saving controller, in which the rotating speed is monitored in real-time and fed back. Based on the feedback of the engine's rpm, the position of the throttle of the engine is adjusted by a linear displacement electromagnet to meet the requirement on the engine power and to control the power of the engine. Similarly, the desired pump pressure is input via a Δp regulating knob into a pump controller, which is a subpart of the energy saving controller. The information of the position of the throttle and the rpm of the engine is input into the controller to get a valid feedback. The output signal from the pump controller serves to control the pump regulator so as to control the pump.
In accordance with another embodiment of the present invention, there is provided a method for controlling the work of the electromechanically-integrated excavator, comprising the steps of (1) determining the movement of the excavator by utilizing a motion controller so as to obtain the motion sequence of the operating devices, incl., the boom, the stick, and the bucket; (2) setting parameters for the starting point of the motion sequence to obtain a Pulse Width Modulation (PWM) signal to control a pilot electro-hydraulic proportional valve, by means of which the main valve driving the operation of each hydraulic cylinder of the operating devices is controlled; (3) obtaining the position information of the operating devices by utilizing the angle sensors mounted on the boom, the stick, and the bucket of the excavator respectively, which information is then transmitted by a bus to the motion controller, wherein the obtained position information is compared with that preset for the operating devices, wherein the control parameters are corrected in real-time by applying the method of adaptive Proportional-Integral-Differential (PID) algorithm, by which the real-time corrected control values are obtained through the PWM output, and thereby, the movement of the operating devices is controlled; and (4) repeating step (3) to control each sequential point in the above motion sequence, and thus achieving the automatic excavating control on a preset motion path.
The excavator of the present invention provides the following advantages:

(1) by utilizing the height detector mounted on the excavator to receive the laser signal emitted by the laser head of the fixedly mounted laser emitter to measure the relative height of the laser beam in comparison with the zero level, the position information of the base excavator is obtained, and thereby the excavating depth and the position of the bucket is adjusted in real-time so as to realize precise control on the movement of the operating devices; in addition, based on the elevation guiding information, after the excavator or excavator body is positioned, the movement of the operating devices can be traced, mapped and controlled in accordance with a kinematic model of the operating devices;
(2) by disposing angle sensors on the boom, the stick, and the bucket of the excavator respectively, the motion of the excavator can be observed in real-time; in addition, the angle sensors can provide the position information of the excavator to yield the operator in performing precise work, and thereby to improve the work efficiency, and even to realize a blind operation; in addition, by adopting the method of intelligent PID control to real-time adjust the PID algorithm according to the position status of the operating devices, the large inertia of the operating devices of the excavator, the strong nonlinearity of the hydraulic system, and the uncertainty of the parameters of the control model can be overcome, and thus the control precision of the excavator is assured;
(3) the monitoring system monitors and displays the main parameters of the system and alarms when these parameters reach certain valued, which enables the operator to obtain the operating conditions of the excavator in a quick manner; in addition, as part of the malfunction diagnosis, specific values of the control parameters of each port can be displayed when the excavator is in operation, and if any malfunction occurs, the position of the malfunction can be detected rapidly and conveniently, so that a servicing action can be taken; and
(4) by employing the mode select switch and the engine speed setting knob and by adopting the combination of the two control modes of constant and variable powers to adjust the position of the throttle of the engine to meet the requirement on power, a harmony among the operation of the engine, the hydraulic pump, and the loading is achieved resulting in energy saving.

Many of the attendant advantages of the present invention will become more readily apparent and better understood as the following detailed description is considered in connection with the accompanying drawings in which:

FIG. 1 is a left side elevational view of an excavator showing the location of sensors in accordance with one embodiment of the present invention;
FIG. 2 is a block diagram of the monitoring system in accordance with one embodiment of the present invention;
FIG. 3 is a block diagram of the automatic control system in accordance with one embodiment of the present invention; and
FIG. 4 is a block diagram of the energy saving control system in accordance with one embodiment of the present invention.

The configuration and the operation principle of the excavator of the present invention will hereinafter be described further in more detail with reference to the preferred embodiments.
With reference to FIG. 1, the operating device of an excavator in accordance with one embodiment of the present invention comprises a boom 1, an arm or a stick 3, and a bucket 6 mounted with angle sensors 2, 4, and 7, respectively. A laser emitter rack 8 with a laser emitter 9 mounted thereon is disposed near the front portion of the stick 3, a height detector 5 is fixedly mounted on the stick 3, the output of the height detector 5 is connected with a monitoring processor. When the excavator is in operation, the laser emitter rack 8 is set to a horizontal status, and the laser head of the laser emitter 9 rotates and emits a laser signal, which is received by the height detector 5 by which the relative height of the laser beam is measured in comparison with the zero level. The signal of the measured relative height is transmitted by a bus to a processor of the monitoring system for processing; the processed signal is displayed on an indicator screen of the monitoring system, and then is transmitted by a communication circuit to a motion controller.
With reference to FIG. 2, the monitoring system of an excavator in accordance with one embodiment of the present invention comprises a monitoring processor, a data storage, a watchdog for protecting the system from specific (software or hardware) failures that may cause the system to stop responding, an indicator screen, an audio alarm, an optoelectronic isolating circuit with isolation elements, a high speed optoelectronic isolating circuit, a revolution counter, a filter, a communication circuit, a motion controller, a boom angle sensor, a stick or arm angle sensor, a bucket angle sensor, a laser emitter, and a height detector, wherein the monitoring processor is connected with the storage, the watchdog, the indicator screen, the audio alarm, the counter, the filter, and the communication circuit, and the optoelectronic isolating circuit is connected with the filter.
The position information from the boom angle sensor, the stick angle sensor, and the bucket angle sensor is transmitted as a signal by a bus to the motion controller, and then is sent via the communication circuit to the monitoring processor for processing. The obtained signal is then displayed on the indicator screen. Based on the laser signal received by the height detector, the relative height of the laser beam in comparison to the zero level is measured, and is transmitted by a bus to the monitoring processor for processing. The obtained signal is then displayed on the indicator screen. The high-speed pulse signal from the engine is sent via the high-speed optoelectronic isolating circuit to the counter to be counted, and then is sent to the monitoring processor. Various on-off signals passed through the optoelectronic isolating circuit and the filter are sent to the monitoring processor for processing. The obtained signal is then displayed on the indicator screen.
In accordance with the monitoring system of the present invention, the pressure, the temperature, and the liquid level at each node can be displayed when the excavator is in operation. In addition, an intelligent control of the operation of the excavator can also be realized. Specifically, the main parameters of the system, including without limitation, the fuel level, the oil pressure, the water temperature, the oil temperature, the low battery voltage, the high water temperature of the engine cooling system, the low fuel, the filter clogging, the air filter deficiency, the high temperature of hydraulic oil, the low oil pressure, the high oil temperature, and the low water level, are monitored and displayed, and alarm is issued when these levels exceed certain preset values. Also, the capability to diagnose malfunctions by the monitoring processor allows the values of the key control parameters of each port to be displayed in real-time when the machine is in operation. If a malfunction occurs, the position of the malfunction can be rapidly and conveniently detected, and corrective actions can be taken in speedily.
With reference to FIG. 3, the operating device of the excavator is regarded as a manipulator with multiple degrees of freedom, wherein the position information of the operating devices is determined by angle sensors 2, 4, and 7 mounted on the boom 1, the stick 3, and the bucket 6, respectively. The signal carrying the position information from the above three sensors is transmitted by a bus to the motion controller 11 of the excavator, in which the precise movement of the operating devices are determined. For example, a movement may be expressed as a horizontal line, a sloped line, an arc line, etc. Thereafter, the signal is sent for analysis in accordance with kinematic and dynamic layouts to obtain a motion sequence of the operating devices, i.e., the boom 1, the stick 3, and the bucket 6. Due to (1) the large inertia of the operating device of the excavator, (2) the strong nonlinearity of the hydraulic system, and (3) the uncertainty of the parameters of the control model, the values of the control parameters on the motion sequence are adjusted in real-time in accordance with the position information of the operating devices by applying adaptive Proportional Integral Derivative (PID) algorithm, and then the real-time-corrected control parameters are obtained as a Pulse-Width-Modulated (PWM) output. The parameters of each point in the motion sequence are set in this way, and the obtained PWM signal is served to control the pilot electro-hydraulic proportional valve by which the main valve driving the movement of each hydraulic cylinder is controlled. At the same time, the variations during the motion process are detected in real-time and the feedback is displayed. The movement of the operating devices results in change of the parameters received by the three sensors, which is then transmitted in real-time by a bus as a real-time feedback. In this way, each point in the motion sequence can be controlled to obtain a precise pathway following. Therefore, the automatic control of the operation of the excavator can be realized by a push of a button.
With reference to FIG. 4, the energy saving mode is selected via the mode select switch and a desired engine revolution speed is input via the engine speed setting knob. Both the mode information and the desired rpm are sent to the engine controller, which is a subpart of the energy-saving controller, in which the rotating speed is monitored in real-time and fed back. Based on the feedback of the engine's rpm, the position of the throttle of the engine is adjusted by a linear displacement electromagnet to meet the requirement on the engine power and to control the power of the engine. Similarly, the desired pump pressure is input via a Δp regulating knob (pressure regulating knob) into a pump controller, which is a subpart of the energy saving controller. The information of the position of the throttle and the rpm of the engine is input into the controller to get a valid feedback. The output signal from the pump controller serves to control the pump regulator so as to control the pump. The engine controller and the pump controller together form an energy-saving controller and realize a good match among the parameters of the engine, the hydraulic pump, and the loading, so as to realize energy saving.

Claims

An electro echanically-integrated excavator comprising a boom (1), an arm or a stick (3), a bucket (6), a monitoring processor, a data storage, a watchdog, an indicator screen, an audio alarm, an optoelectronic isolating circuit, a high speed optoelectronic isolating circuit, a revolution counter, a filter, and a communication circuit; wherein said monitoring processor is connected with said storage, said watchdog, said indicator screen, said audio alarm, said counter, said filter, and said communication circuit; said optoelectronic isolating circuit is connected with said filter; and said high speed optoelectronic isolating circuit is connected with said counter.
The excavator of claim 1 further comprising a motion controller having an input; a boom angle sensor (2), a stick or arm angle sensor (4), and a bucket angle sensor (7), each angle sensor having an output; wherein said outputs of the angle sensors (2,4,7) are connected with said input of the motion controller; and said motion controller is connected with said monitoring processor via said communication circuit.
The excavator of claim 1 further comprisipg a laser emitter rack (8) set near the front portion of the excavator, a laser emitter (9) mounted on the laser emitter rack, and a height detector (5) fixedly mounted on the stick (3) of the excavator; wherein the output of the height detector is connected with the monitoring processor.
The excavator of claim 1 further comprising an engine having a throttle and having an engine speed; a hydraulic pump having a pump pressure and having a pump control regulator; a linear displacement electromagnet; an energy-saving controller having an engine controller and a pump controller; said pump controller having a pump controller output signal; a mode select switch having a position for a normal operation mode and an energy saving operation mode; an engine speed setting knob; and a pressure regulating knob; wherein said position of said mode select switch is transmitted to said engine controller; said engine speed is set via said engine speed setting knob and transmitted to said engine controller; said pump pressure is set via said pressure regulating knob and transmitted to said pump controller; said engine speed is monitored in real-time and fed back to said engine controller; the position of said throttle is adjusted by said linear displacement electromagnet; the position of said throttle and said engine speed are input into said energy-saving controller; and said pump controller output signal controls said pump regulator.
A method for controlling movement of the excavator of claim 2 comprising
(1) setting a movement trajectory for the excavator, and obtaining a motion sequence of said boom (1), said stick (3), and said bucket (6) by utilizing said motion controller, said motion sequence comprising a plurality of sequential position points;

(2) obtaining a pulse width modulation signal corresponding to said movement trajectory for controlling the operation of said boom, said stick, and said bucket;

(3) obtaining position information of said boom (1), said stick (3), and said bucket (6) by utilizing said angle sensors (2,4,7) mounted on said boom, said stick, and said bucket; transmitting said position information via a bus to said motion controller; comparing said position information with said movement trajectory; and correcting said pulse width modulation signal in real-time by applying proportional-integral-differential algorithm;

(4) repeating step (3) to control the movement at each sequential point in said motion sequence.