Method For Regulating the Drive of a Shearing or Heading Machine

Abstract

In a method for controlling the drive of a shearing or heading machine for cutting a round, as a function of manipulated variables such as the movement speed of the cantilever arm, the position of the cutting tools and/or the power consumption of the drive motors and the pressure in hydraulic actuating cylinders, a minimum and a maximum target value are determined for the movement speed of the cantilever arm, and at least two factors each having values of between 0 and 1 are calculated for the manipulated variables as a function of measurement values, the measurement values at least comprising cutting tool position data compared to set data corresponding with a set profile, motor load measurement data and cantilever arm movement speed measurement data, and the movement speed of the cantilever arm is controlled as a function of the product of the set speed and the respectively calculated factors.

Description

The invention relates to a method for controlling the drive of a shearing or heading machine for cutting a round, as a function of manipulated variables such as the movement speed of the cantilever arm, the position of the cutting tools and/or the power consumption of the drive motors and the pressure in hydraulic actuating cylinders.

For controlling the advance heading of a shearing or heading machine, a number of more or less general methods have become known. From DE 36 31 087, it can be taken that the operation and state data of a winning or partial-cut cutting machine used in underground mining are continuously detected and fed to a computer for evaluation. From those data, the computer determines the cause of failure using a diagnose system, and subsequently initiates complex measures to remove the failure. The computer described there, however, above all serves to non-erasably store the failure and/or its causes until removal in order to subsequently enable the taking of suitable measures even after the occurrence of a failure. Such diagnose, in the main, requires complex evaluations and specific programming tailored to a specific shearing or heading machine. Detailed algorithms are not offered there. DE 29 19 499 C2 shows and describes a method for controlling the cutting horizon of roll cutter machines, in which the cutter force is continuously captured on the rotating roll body and compared with given limiting values. When exceeding those limiting values, a change in the height adjustment is initiated.

EP 0 807 203 B1 finally shows and describes a system for the continuous control of a mining or advance working machine, which includes a number of measuring sensors and, in particular, angle encoders and linear encoders in order to capture the position of the cutter head of a cantilever arm. Via a defined computation program, adjustment values are generated for the proportional control valves of the drive units such as, for instance, the pivoting cylinders of the cutter bar or the linear drive of the cutter head to thereby ensure the compliance with a preselected profile.

The invention aims to provide a method of the initially defined kind, which will do with a minimum of parameters to be each defined in a machine-specific manner, and which can be universally used for different constructions of mining or advance working machines. Essential to the control algorithm proposed by the invention is to be the fact that the parameters are merely dependent on the drive itself and on the machine geometry, but independent of the actual conditions at the mine face, so that the adjustment values respectively required for different machines can be input individually and without complex programming knowledge. To solve this object, the method according to the invention of the initially defined kind essentially consists in that a minimum and a maximum target value are determined for the movement speed of the cantilever arm, that at least two factors each having values of between 0 and 1 are calculated for the manipulated variables as a function of measurement values, said measurement values at least comprising cutting tool position data compared to set data corresponding with a set profile, motor load measurement data and cantilever arm movement speed measurement data, and that the movement speed of the cantilever arm is controlled as a function of the product of the set speed and the respectively calculated factors. By specifying each a minimum and a maximum target value for the movement speed, it will do to determine these values once, for instance by the aid of a valve description. The minimum target value for the pivot speed in this case corresponds to that control current for the proportional control valves, which causes a movement at all. The respective maximum target value for the movement of the cutting unit, in general, amounts to 100% of the machine-specific maximum pivot speed, yet may also be adjusted to a defined speed on the basis of cutting technical criteria. By determining a plurality of multiplicatively linked factors for different measurement values, an extremely precise control is achieved, which, in the event of deviations of individual ones of these values, enables the respective cancellation of the target values until stoppage. The individual factors may each assume values of between 0 and 1, wherein the fact that already a single one of these factors assumes the value of 0 will cause the pivot speed to be accordingly reduced to 0, due to the multiplicative linkage.

Advantageously, the calculation of the individual factors is performed in a manner that the individual factors each take into account a separate measurement value for the manipulated variables such as, e.g., the motor load, the distance of the position coordinates from target coordinates for the profile to be mined, the pivot speed of the cantilever arm and/or the rotational speed of the mining tools. This, for instance, results in such a factor k assuming a value of between 0 and 1 and cancelling the movement as soon as more than the nominal load is taken up. Another multiplicatively linked factor k, which may likewise assume values of between 0 and 1, may cancel the movement as soon as the cutting unit approaches a target point, in order to stop said movement in time and/or enable a reversal of the direction of movement. Finally, a further k-value can be determined as a function of time measurement values, which becomes effective after an imminent blockage or at the occurrence of a blockage and, in the following, will trigger a complex blockage algorithm for a starting control.

In an advantageous manner, the method is performed such that measurement values for changes in the motor load, pivot speed and/or rotational speed are determined over time and fed to a freely programmable switch mechanism and to the drive control as separate manipulated variables so as to enable not only the safe detection of the actual load on the drive, such as, e.g., the current of the cutting motor, but also time-dependent changes of this load. In this case too, it is again feasible to preset suitable limit values by selecting the respective k-values for a particular machine type, and to indicate by a nominal value the nominal load of the drive sought during the cutting procedure.

That load on the drive which is to cause the control to start the blockage protection algorithm may likewise be defined individually and trigger the respective protection mechanisms, as this limit load continues over a defined time. To this end, the configuration is preferably devised such that at least one delay time is feedable to the freely programmable switch mechanism as a manipulated variable via which the starting speed is kept at or near the minimum set movement speed upon detection of a blockage. The linkage of the target values for the movement speed, which may basically be target values of the control current for the proportional control valves of the hydraulic drive, with individually defined factors can be accordingly supplemented by adding further factors in order to achieve an enhanced accuracy of the control. The invention basically aims to control the movement speed of the cutting unit always in a manner that the cutting drives will possibly always be operated within the nominal load range, i.e. at the optimum power consumption and the correct operating pressure, whereby cutting technically relevant maximum speeds are not to be exceeded.

The control as a function of the nominal load as effected according to the invention serves to adapt the movement speed of the cutting unit such that the cutting motor itself will possibly be operated within the nominal load range. The coordinate control and the respective factor likewise are to safeguard that the target points on the cutting path be reached with a defined geometric accuracy. The target or inversion points in this case are not to be overtravelled and the movement speed is to be taken back accordingly closely downstream of the target point.

The separate blockage control provided by the invention is, however, of essential importance. In the event of an instantaneous overload or blockage of the cutting motor, it will, as a rule, do to briefly place the cutting unit out of engagement by stopping the advance heading speed. The cutting unit is thus relieved, whereupon the round may be continued again. If, however, a particular load value, i.e. the load value critical for a blockage, is exceeded over a defined time, a blockage protection algorithm can be activated to recognize an actual blockage well before its occurrence. In this case, the cutting unit can be placed out of engagement as rapidly as possible in order to prevent an imminent blockage of the cutting motor. Wherein, if no movement in the counter direction is required, the advance heading movement must merely be stopped, whereupon slow starting can be effected as a function of the given time adjustment values to cause the cutting unit to reenter into full engagement only upon expiration of a delay time. At the same time, the k-factor may define a real speed portion to which the cutting unit is to be delayed when reentering into engagement after a blockage at the blockage point. The cutting speed can, thus, be initially reduced after the delay time to be only increased to full speed after a further time interval, the delay time usually being the time that is still run at minimum speed by the cutting unit after having passed the blockage point, before its movement can again be accelerated to maximum speed. The relevant time that is to trigger such a blockage protection algorithm can be individually set and signifies the time over which the load on the drive must be exceeded in order to trigger the blockage algorithm for subsequent control.

Similarly, for approaching the target point based on the position measurement data detected, it is possible to not only define a distance to the cutting unit to the target point, starting from which the movement of the cantilever arm will be reduced accordingly, but also adjust a tolerance value by which the target point has to be reached before enabling the next movement.

In the event of a blockage or imminent blockage, the respective position coordinates of the blockage point can be determined, and a separate time interval can be adjusted, within which the time unit accelerates the movement to maximum speed after a new passage of the blockage point, and hence again releases the generally applied control.

Hence results, in the main, that different machine types can be taken into account by a defined, small number of individual parameters and that no complete, complex controls have to be programmed for every machine type. Unlike the usual two-position controls provided on partial-cut cutting machines, the parameters used in the algorithm according to the invention are each of physical relevance and relatively simple to determine. These parameters according to the invention are substantially only dependent on the drive unit and on the machine geometry, and no additional corrections have to be made as a function of engagement or mine face conditions. Therefore, machines of the same type can always be adjusted with identical values. Due to the independence of actual on-site conditions, the control algorithm will respond to changing rock or engagement conditions in a largely insensitive manner during a round, the described algorithm enables the standardization of the control concept for different machine types, thus substantially enhancing the maintainability of the systems. At the same time, an extremely safe and sensitive detection of critical limit values is enabled by the multiplicative linkage of the individual parameters so as to safely avoid damage and long downtimes.

Claims

1-4. (canceled)

5. A method for controlling the drive of a shearing or heading machine for cutting a round as a function of manipulated variables, comprising the steps of:

determining a minimum target value and a maximum target value for movement speed of a cantilever arm of the machine;

calculating at least two factors, each of said factors having values of between 0 and 1, for manipulated variables as a function of measurement values, wherein said manipulated variables are one or more of movement speed of the cantilever arm, position of cutting tools of the machine, power consumption of drive motors of the machine, and pressure in hydraulic actuating cylinders of the machine, and wherein said measurement values are one or more of cutting tool position data compared to set data corresponding with a set profile, motor load measurement data, cantilever arm movement speed measurement data, cantilever arm pivot speed measurement data, mining tools rotational speed measurement data, and distance of position coordinates from target coordinates for the profile to be mined; and

controlling the movement speed of the cantilever arm as a function of a product of a set speed and the respectively calculated factors.

6. A method according to claim 5, wherein each of said factors takes into account a separate measurement value for the manipulated variables.

7. A method according to claim 5, wherein

measurement values for one or more of changes in motor load, changes in pivot speed, and changes in rotational speed, are determined over time, and wherein

said measurement values for said one or more changes in motor load, changes in pivot speed, and changes in rotational speed determined over time are fed to a freely programmable switch mechanism, and to a drive control of the machine, as separate manipulated variables.

8. A method according to claim 6, wherein

measurement values for one or more of changes in motor load, changes in pivot speed, and changes in rotational speed, are determined over time, and wherein

said measurement values for said one or more changes in motor load, changes in pivot speed, and changes in rotational speed determined over time are fed to a freely programmable switch mechanism, and to a drive control of the machine, as separate manipulated variables.

9. A method according to claim 7, further comprising the steps of:

feeding at least one delay time to the freely programmable switch mechanism as a manipulated variable, and

upon detection of a blockage, keeping a starting speed of the movement of the cantilever arm at or near the minimum target value for movement speed during said delay time.

10. A method according to claim 8, further comprising the steps of:

feeding at least one delay time to the freely programmable switch mechanism as a manipulated variable, and

upon detection of a blockage, keeping a starting speed of the movement of the cantilever arm at or near the minimum target value for movement speed during said delay time.