Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q7/00—Arrangements for handling work specially combined with or arranged in, or specially adapted for use in connection with, machine tools, e.g. for conveying, loading, positioning, discharging, sorting
  • B23Q7/14—Arrangements for handling work specially combined with or arranged in, or specially adapted for use in connection with, machine tools, e.g. for conveying, loading, positioning, discharging, sorting co-ordinated in production lines
  • B23Q7/1426—Arrangements for handling work specially combined with or arranged in, or specially adapted for use in connection with, machine tools, e.g. for conveying, loading, positioning, discharging, sorting co-ordinated in production lines with work holders not rigidly fixed to the transport devices
  • B23Q7/1436—Arrangements for handling work specially combined with or arranged in, or specially adapted for use in connection with, machine tools, e.g. for conveying, loading, positioning, discharging, sorting co-ordinated in production lines with work holders not rigidly fixed to the transport devices using self-propelled work holders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61C—LOCOMOTIVES; MOTOR RAILCARS
  • B61C13/00—Locomotives or motor railcars characterised by their application to special systems or purposes

Definitions

• the invention relates to a transport device with self-propelled workpiece carriers in the form of a carriage, carriage or the like.
• a transport device with self-propelled workpiece carriers in the form of a carriage, carriage or the like.
• One such is known, for example, from ⁇ P-OS 0 285 527.
• the known device comprises a rail network on which autonomous wagons move.
• the cars each have their own drive and energy source. Stations are arranged along the rail network, at which workpieces transported by the wagon are processed.
• Each car is equipped with a plurality of sensors and switches via which travel control commands are transmitted to the car by signal transmitters arranged in the roadway.
• a forward-facing optical distance sensor is located on the front.
• There is an inductive sensor in the floor of the car which is activated by signal strips on the road.
• the car If the distance sensor detects an obstacle or a car traveling in front, the car also brakes to crawl speed. If the obstacle is immobile, it hits the obstacle at the creeping speed. The front rocker is then actuated by the impact and the carriage is thereby stopped. If the obstacle is removed and / or there is no pressure on the front rocker, the car resumes driving at full power.
• the sensor switch system allows the car to be controlled in a restricted manner even in non-regular operating situations, for example in the event of an obstacle on the road. This is recognized by the distance sensor, which then initiates a braking process. The car hits the obstacle at crawl speed and is stopped by the front rocker that is actuated.
• the distance sensor is defective or if it does not recognize the obstacle for other reasons, the obstacle is impacted at full speed. In this case, too, it is stopped by operating the front rocker. The journey continues again when the pressure on the front rocker is removed. In the case of movable obstacles, this can result in the car jerking the obstacle in front of it without being finally stopped. If, in the same situation, the distance sensor is functional, but the front rocker is defective, this results in a "counter-approach" against the obstacle, the car constantly trying to To reach creep speed. In the case of heavy or almost immovable obstacles, this can easily lead to motor overload. There is an increased risk of accidents for a person if, for example, a hand is pinched by a car with a defective distance sensor.
• the inductive sensor on the bottom of a car is defective, this leads to the car entering a stopping point at maximum speed, where it is abruptly shut down by actuating the bottom switch. After the stop lock is removed, the car continues its journey with maximum performance and moves to the next stop point in the same way, that is, at maximum speed. The faultiness of the floor inductive sensor is not discovered.
• a first transport device provides a signal evaluation logic which stops a car when a signal sequence that is not possible due to the time sequence occurs. For example, wagons that drive into a stop point without braking due to a defective ground inductive sensor are immediately and permanently stopped.
• a further transport device provides a two-stage front switch in the form of a rocker which permanently stops a car in the event of a very hard impact.
• the front switch is expediently implemented as a series of light barriers which are interrupted depending on the hardness of the impact.
• Another transport device provides a shock sensor, the response of a car stops in the event of a very hard impact.
• an energy extraction monitoring arrangement is provided which stops the car when the engine is overloaded beyond a permissible period.
• a combination initially has the advantage that if one individual system fails, another can take over its function. In this way, the safety of a transport device according to the invention can be significantly increased. If, for example, the car drives against a soft obstacle without braking and the front rocker does not respond with the second switch stage, the energy extraction monitoring system stops the car. Likewise, the energy extraction monitoring arrangement shuts down the car if the shock sensor does not respond to an obstacle in the case of an unbraked collision. If, for example, the signal evaluation logic fails, the car is stopped at a stopping point by responding to the shock sensor.
• Another major advantage of a combination is the mutually supportive definition of a hazard threshold, which enables a shorter and / or more sensitive reaction to hazard or environmental conditions.
• FIG. 1 shows a structure of a carriage with a section of an associated one Roadway
• FIG. 2 shows the entry of a car into a free stop
• FIG. 3 shows the entry of a car into a stop already occupied by another car
• FIG. 4 shows a structure of a front switch
• FIG. arrangement and FIG. 6 shows a profile of an energy extraction curve.
• the transport device contains a branchable rail network with processing stations arranged thereon and autonomous workpiece carriers, hereinafter referred to as wagons, which move on the rail network.
• FIG. 1 schematically shows a carriage with a section of the carriageway. Travel commands are fed to the carriage via sensors 12, 18, 22 and switches 23, 12.
• the carriages are equipped with a distance sensor 12 directed in the direction of travel, a pressure switch 13 mounted on the front in the form of a rocker, and on the bottom with an inductive sensor 18, a pair of track sensors 22 and a stop switch 23 on the bottom.
• the car-side switches 13, 23 and sensors 12, 18, 22 are activated by signaling devices 16, 17 arranged in the roadway or by impact.
• Each car is equipped with a central control unit in the form of a microcomputer 10, which coordinates all the signals coming in via the sensors and switches and performs the entire driving control of a car.
• the microcomputer 10 is connected to all active car elements, such as the drive, sensors, switches, etc.
• a stop consists of a signal strip 16 applied to the roadway, at the end of which there is a mechanical lock 17 which can be controlled from the outside and which marks the stopping point.
• the length of the signal strips 16 is the same in front of all stopping points.
• the value of the signal strip length is stored in the microcomputer 10.
• FIG. 2 The entry of a carriage 10 into a free stop point is shown in FIG. 2.
• the inductive sensor 18 arranged on the ground recognizes the signal strip 16 when passing over it and emits a signal to the microcomputer 10.
• the microcomputer 10 then brakes the car precisely to the stopping point if the length of the signal strip 16 is known.
• the mechanical lock 17 actuates the bottom switch 19, which emits a signal to the microcomputer 10, which then stops the car.
• FIG. 3 a possible course of the speed over the braking distance during such a regular stopping process is shown in a diagram.
• the distance S traveled is plotted as the abscissa and the speed V as the ordinate.
• the real course of the curve can of course deviate from that shown, in particular it does not have to be linear.
• Driving into a stop point already occupied by another car is shown in FIG. 3.
• the distance sensor 12 first recognizes the rear 14 of the car standing in the stop point as an obstacle and thus triggers a braking process by means of which the car speed is released a value corresponding to the distance is reduced.
• the inductive sensor 18 on the bottom responds. The car then brakes precisely on the rear 14 of the second car standing in the stopping point.
• the braking process is not triggered by the distance sensor 12 responding but by activation of the ground inductive sensor 18. This emits a signal to the microcomputer 10. which signals a free stop. If an additional signal from the distance sensor 12 is missing, which signals an obstacle, the microcomputer 10 carries out the braking process precisely to the stopping point marked by the lock 17. The car therefore hits the rear 14 of the stationary car at an insufficiently decelerated speed, where it is stopped by the rocker 13 on the front, which is actuated in the event of an impact.
• a signal evaluation logic in each car checks the chronological sequence of the response of the sensors or switches.
• the signal evaluation logic is expediently implemented in the microcomputer 10.
• the regular response sequence of the sensors and switches is: Distance sensor 12 - bottom-side inductive sensor 18 - front-side rocker 13.
• the sequence obtained due to a faulty sensor function is:
• the front-side switch designed as a rocker 13 is advantageously designed in two stages.
• the first state, position 34 in FIG. 4 is actuated by a regular impact, for example when a car in a stopping point collides with another car already at the stopping point at creep speed.
• the switch then gives a signal the control unit 10, on the basis of which it temporarily stops the car. If the pressure on the rocker 13 is no longer present, the rocker returns to the starting position 33.
• the signal corresponding to the rocker position 32 is therefore also omitted, whereupon the control unit 10 sets the carriage in motion again.
• the second switching state, position 35 is actuated in the event of an irregular impact.
• an irregular impact Such a case occurs, for example, when a car, due to a non-functioning distance sensor, hits an obstacle located in the carriageway at maximum speed without being braked; this can be another standing car, for example.
• the second switch stage is actuated by a hard impact caused in this way.
• the car On the basis of the signal given to the control unit 10, the car is permanently stopped. External reactivation is then required for reactivation.
• the two-stage switching arrangement is preferably realized by means of light barriers 31, 32 and a spring damper system 39. An exemplary embodiment of this is shown in FIG. 4. Two rocker bars 36, 37 of different lengths are fixedly connected to the front rocker 13.
• the rocker is dynamically coupled to the carriage via a spring damper system 39.
• the ends of the interrupter rods 36, 37 are guided between two light barriers 31, 32 mounted on the carriage at the same distance from the front rocker. Both light barriers 31, 32 are connected to the control unit 10. In the starting position 33, both interrupter rods 36, 37 do not interrupt the light barriers 31, 32 assigned to them. If the rocker 13 is actuated by pressure, the longer interrupter rod 36 is pushed between the light barrier 32 and interrupts it when the pressure is slight. The light barrier 31 assigned to the shorter interrupter rod 37 is not interrupted. Only when there is high pressure as a result of a very hard impact is the shorter interrupter rod 37 shifted horizontally to such an extent that it interrupts the light barrier 31 assigned to it.
• the signal emitted by the light barrier 31 triggers a permanent carriage shutdown.
• a shock sensor 24 is provided, which also responds to a non-regular hard impact and emits a signal, on the basis of which the microcomputer 10 permanently stops the car.
• a threshold value for the force of an impact, beyond which the shock sensor 24 responds, can be specified from outside *.
• the purpose of the shock sensor 24 is to trigger a permanent vehicle shutdown in such cases in which an obstacle on the road is not recognized by the distance sensor 12 and the front rocker 13 does not respond. This can be the case if there is an obstacle above the rocker 13 and only hits the load on a wagon. It can of course happen that both the rocker 13 on the front and the shock sensor 24 respond in the event of an impact to an obstacle.
• An energy extraction monitoring arrangement 40 is provided as a further protective device for monitoring the power withdrawn from the battery. If a car exerts a high output over a differential period of time without the car speed changing accordingly, the microcomputer 10 stops the car. This situation can exist when a car is running against a flat, moving obstacle. In this case, it is not stopped either by actuating the rocker 13 on the front or by responding to the shock sensor. The car therefore tries to reach the target speed with maximum performance.
• the structure of such an arrangement is shown in simplified form in FIG.
• the energy extraction monitoring arrangement 40 consists of a current measuring device 41 and a signal processing 42-46 implemented in the microcomputer 10.
• the current measuring device 41 is connected to the motor-side output of the batteries.
• the output signal of the current measuring device is supplied to the evaluation unit 40 as an energy signal.
• the energy extraction monitoring arrangement 40 is connected on the output side to the drive 20.
• the output from the battery 21 to the drive 20 is
• the energy extraction monitoring arrangement 40 therefore contains a current meter 41 which detects the average current flow from the battery 21 to the motor 20 and generates a corresponding electrical signal. This signal is fed to a squarer 43.
• the time duration T of a current measurement carried out by the ammeter is determined by a time control 42.
• the squared signal coming from the current meter 41 is multiplied by a signal emitted by the time control and corresponding to the time T.
• the result obtained in this way corresponds to the energy drawn from the battery in a time period T.
• a comparator 45 compares this result with a predetermined limit value 46 stored in a memory 47.
• the energy extraction monitoring arrangement 40 emits a signal to the drive 20, whereupon the carriage is stopped permanently.
• the time T and the limit value 46 are generally fixed values which are stored in the evaluation unit 40. They are determined depending on the operating requirement profile and the particular engine of the car. The two values are expediently determined on the basis of a typical energy extraction curve recorded over a longer period of time during normal operation, as shown in FIG. 6. In it is over time t
• the values T and the limit value 46 can then be determined, for example, on the basis of the relationship P ⁇ - I J » t - , Agriculture Therein mean: P the mean loss line in the interval ⁇ n z -n ⁇ ), I the mean current, i the mean current in a measurement interval T, T a time interval, n2, nl the numbers of the beginning and end of the total period over which is averaged, lying time intervals. T becomes appropriate chosen that typical short-term overloads do not lead to vehicle shutdown.
• the limit value 46 should be sufficiently above the value P so that typical performance fluctuations do not lead to the car being stopped.
• the proposed implementation of the energy extraction monitoring arrangement 40 is exemplary. Of course, especially since a significant part of the circuit is implemented in the form of software, it can also be constructed differently with the same mode of operation.
• the combination of the devices represents protection of the car in the event that the distance sensor 12 does not work properly. This can also be caused, for example, by contamination of the sensor.
• a large number of different non-regular operating states occur with the same probability, which can only be detected overall by means of a combination of the devices.
• These include in particular various types of obstacles. We have to differentiate between soft and hard, between flat and high, between movable and immovable, and between light and heavy obstacles.
• the shock sensor responds to the obstacle and stops the car. Since it is of particular importance for the operation to recognize a possible defect of the distance sensor 12 as quickly as possible, it is advantageous to additionally provide a signal evaluation logic in each case. If the distance sensor 12 is defective, a carriage is indeed protected by the further safety devices, but a defect of the distance sensor cannot be assigned with certainty.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transportation (AREA)
• Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)

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Applications Claiming Priority (2)

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ID=6405934

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Citations (5)

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• 1990
  • 1990-05-08 DE DE4014701A patent/DE4014701A1/de active Granted
• 1991
  • 1991-04-26 DE DE59106136T patent/DE59106136D1/de not_active Expired - Fee Related
  • 1991-04-26 EP EP91908356A patent/EP0482153B1/de not_active Expired - Lifetime
  • 1991-04-26 US US07/768,888 patent/US5211115A/en not_active Expired - Fee Related
  • 1991-04-26 WO PCT/DE1991/000350 patent/WO1991017020A1/de active IP Right Grant

Patent Citations (5)

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