The invention relates to a system suitable for feeding livestock, and to a robot system for feeding livestock.
As a feeding robot, the robot, autonomously driving in the system between the storages and the stables, must mix well and quickly and possibly cut the feed loaded, should it not be loaded premixed in the robot used as distributing robot. Considerable electrical power is required, especially for mixing. A robot with a loading capacity of approx. 3 m3 requires about 11 KW at a feed density of about 350 kg/m3. Considerable electrical power is required also for self-driving either via a suspension rail or on a chassis also to and from the dispensing points and for dispensing e.g. using a lateral pusher, dispensing rollers and/or by way of a cross conveyor belt. The robot performs, for example, 35 cycles per day. Due to the high power demand, a single docking device predetermined in its location has in prior art previously been installed in the feed preparation area, and/or all driving routes are equipped with power rails also in the stables. However, if the system comprises several buildings, then the power rail must also be installed among the buildings, obstructing the traffic in the system and causing extreme costs for the supporting structures. In addition, seeing many power rails sections and their suspensions outside of buildings is unsightly.
The invention is based on the object of providing a system of the kind mentioned above and a robot that enable energy-efficient operation.
This object posed is satisfied by the features of the claims.
Since a power rail line extending along the storages is provided with at least one docking device as an entry or exit point for the robot at least in the feed preparation area, filling can be done efficiently and, if necessary, feed can be mixed everywhere in the entire region of the feed preparation area without use of the battery. Mixing and blending is in fact the job with the highest power consumption. While work is being carried out at or in the robot in the feed preparation area and can possibly be supplied with power from the power rail line, the battery can simultaneously be charged or topped up everywhere. The robot then does not need to be located at a predetermined position, but it is connected substantially permanently to the power rail line during work. Once the robot has completed e.g. its mixing work or has been loaded, it drives autonomously along the driving routes and to and into the stable for dispensing, where the driving and the dispensing operation can be done with electricity from the battery which was already fully charged in the feed preparation area. The charging device can be located in the robot, and/or one or more charging devices are located in a stationary manner and connected to the power rail line.
The robot is either a feeding robot, which can have two mixing elements in the container, mix the feed automatically and optionally cut and dispense it in a rotational speed-controlled manner, or a distributing robot, which is loaded with feed or even already mixed feed in the container and dispenses it e.g. without speed control.
Several docking devices and/or power rail lines can even be installed in the feed preparation area.
Instead of 12 V or 24 V batteries with standard low voltage, the robot comprises at least one high-voltage battery which is connected at least on the output side to the respective intermediate circuit of the frequency transformer. The high-voltage battery and the frequency transformer provided for rotational speed control of the electric drive allow the use of highly efficient electric motors that are relatively inexpensive and deliver high performance, where the connection of the battery to the circuit entails the significant advantage of being able to omit expensive and heavy converters, and supply the electric drive directly via the intermediate circuit of the frequency transformer during battery operation with high DC output voltage of the battery. In addition to the power rail line in the feed preparation area, at least one further power rail line with at least one docking device can be provided in at least one stable. This power rail line in the stable does not necessarily need to span the entire feeding lane, but only to ensure that the robot is temporarily connected to the power rail line at least when visiting or when leaving the dispensing points and recharges the battery in order to be able to operate with full battery power, for example, when dispensing. A respective confined power rail line with a docking device can also be provided in the system also for other external storages for feed or feed additives.
Sections of the driving route between the feed preparation area and the respective stable are advantageously clear of power rail lines and docking devices, so that this open area is easily accessible for other traffic and is not obstructed by a power rail line and its suspensions.
The transmission of the operating, working and/or charging current from the power rail line to the robot can be galvanic, for example, using current collectors configured as sliding contacts, or also without contact.
Each docking device can comprise an entry guide or a forced steering system for the robot, preferably its current collector. Current collectors are advantageously each provided in duplicate in order to always ensure contact at switches or the like. Instead of or in addition to an entry guide, it is possible to configure the current collector or current collectors to be resiliently movable in order to ensure a proper docking operation.
In order to be able to use a powerful electric drive and save additional expensive equipment, such as converters, it is advantageous to have the power rail line provide three-phase current with at least approximately 230 VAC, preferably approximately 400 VAC, for the frequency transformer of the electric drive and possibly for the battery charging device, where the electric drive can advantageously have a synchronous or asynchronous motor which can be operated in star or delta connection. If only 230 V single-phase current is available in the grid, then it is converted to three-phase current for the power rail line.
A particularly important aspect of the invention with independent significance is that the respective battery is a high-voltage battery with high DC output voltage for the intermediate circuit of the frequency transformer. Particularly suitable are nickel/metal hydride batteries or lithium batteries or nickel-cadmium batteries (LiNiMnCo or LiMnCo for example), the advantages of which are a high charging capacity and rapid charging processes. Direct current can be supplied alternatively from other high-voltage batteries suitable for this purpose.
In order to save expensive converters, it is particularly important to connect the high-voltage battery on the output side to an intermediate circuit of at least one, preferably all frequency transformers comprising an AC primary circuit connectable to the power rail line, the DC intermediate circuit, and an AC secondary circuit connectable to the electric motor.
It is there advantageous to have the DC output voltage of the battery to be higher by a factor of >1, preferably theoretically by 1.41 (root of 2), than the alternating voltage from the power rail line acting upon the primary circuit of the frequency transformer. This increasing factor allows battery B to deliver an increased DC output voltage with which motor control is efficiently effected in the intermediate circuit of the respective frequency transformer.
Three-phase AC current at 400V, 50 Hz that can be supplied to the primary circuit of the frequency transformer is often available in Europe. The DC voltage in the intermediate circuit of the frequency transformer is then approximately 564V (factor about 1.41). With six or a multiple of six 96-volt batteries, approximately 576 volts, with full batteries even up to about 680 volts, are then available for use. The electric motor is operated in star connection. In the US and Canada, three-phase current at 230 volts, 60 Hz, is often available in three phases for the supply to the primary circuit. Direct current at about 324 volts is applied to the intermediate circuit. With three or a multiple of three 108-volt batteries, at least approximately 324 volts are usable. The electric motor is operated in delta connection. The same electric motors can then be used in the robots in both market sectors.
The voltage values mentioned are non-restricting theoretical examples. The DC voltage supplied to the intermediate circuit can vary in practice, e.g. be higher by about 10%.
In order to charge the high-voltage battery without a separate charging device, it is advantageous to connect the battery via a separate charging line to the intermediate circuit of at least one frequency transformer, monitored e.g. by a switch or a relay. Suitable for this purpose is, e.g. the frequency transformer of an electric drive that is not constantly in operation.
Another important aspect is that the docking device comprises a safety circuit, with which low voltage up to, for example, a maximum of 48 V is provided until the robot is substantially fully docked, and which is switched to three-phase current only with full docking. This safety circuit prevents live parts from being contacted during the docking process for reasons of accident or vandalism, which would cause damage or injury to people.
The feeding robot advantageously comprises electric drives for mixing elements, for driving and/or steering wheels and for at least one dispensing device. The electric drives can comprise only electric motors, but also gears such as planetary gears and the like, for example, to be able to produce low driving rotational speeds with high torques at efficient high output rotational speed of the electric motor.
Since the mixing elements of the feeding robot and the dispensing device have a relatively high power demand, especially when dispensing, it is advantageous to assign each mixing element its own variable-speed electric drive, or equip both mixing elements with a common electric drive having a drive train with a clutch between the mixing elements. These solutions are particularly advantageous in terms of energy usage. It is a fact that the torque of, for example, a vertical mixing auger as a mixing element depends strongly on the auger diameter. With a container content of, for example, 2.5 or 3 m3, it is therefore advantageous to equip two mixing elements with smaller diameters of about 80 cm, as compared to a container of the same size with a single mixing auger of about 1.5 m in diameter. This also applies to larger containers of, for example, 10 or 12 m3. Because dispensing can then be commenced by first driving only one mixing element until the associated part of the mixing chamber in the container is almost empty. Only then is the other mixing element driven. It is then not necessary to take the total content from 0 to dispensing speed, but only one, and then with a time delay, the second mixing element is instead switch on once the container content has reduced. It is also possible to proceed in such a way that the second mixing element first conveys feed to the first mixing element and is then switched off again, etc., until the content in the rear part of the container does not significantly differ from the content of the front part at the end of the dispensing cycle. Both mixing elements can then be driven permanently, while requiring only low drive torques. The dispensing process should namely be done with the lowest possible rotational speed, for example, of about 15 to 20 rpm. However, in order not to hurl out the remaining feed, the rotational speed at the end of the dispensing cycle must increase up to, for example, 50 rpm, which is possible by use of the respective frequency transformer, but alternatively also by use of a shiftable gear.
In one advantageous form of the feeding robot, a control is provided for the mixing elements and possibly for the dispensing device with which only one of the mixing elements or both is or can be respectively driven and controlled in terms of rotational speed in dependence of operating parameters provided by sensors. Such operating parameters can be the respective power demand, the loading weight in the container, the filling level in the container or the dispensing quantity per unit time, or similar significant operating parameters.
In one advantageous embodiment of the system, the driving routes of the robot are predetermined by a guide rail network, preferably with switches and branch-offs, like the power rail network of the power rail lines.
The respective power rail line is installed in a stationary manner approximately parallel to the ground and slightly above the container of the robot, so that the driving motions of the robot are not obstructed and it still obtains easy access to the power supply.
In one advantageous embodiment of the robot, namely of the feeding robot or the distributing robot, the battery is a high-voltage battery operable with a high DC output voltage. Particularly suitable high-voltage batteries are inexpensive and high-performance nickel/metal hydride or lithium or nickel/cadmium batteries that can be employed for a long time in this application. Alternatively, other types of high voltage batteries can be used.
Embodiments of the object of the invention are explained with reference to the drawings, where
System A is electrically operable and energetically highly efficient because robot R can visit several points in at least one feed preparation area 1 where it has three-phase current available, e.g. in order to perform work with high power demand such as mixing and cutting feed with three-phase current and then always top up or recharge or fully charge at least one onboard battery, where battery B is advantageously a high-performance high-voltage battery such as a nickel/metal hydride battery or a lithium battery or a nickel/cadmium battery or a so-called traction battery with stacked films. The three-phase current, high-voltage battery B, and the power supply available at several points in combination with high-performance variable-speed electric motors in electric drives 14 of the components of robot R enable failure-free continuous operation under optimum conditions, which contributes to the energy efficiency of system A.
Feed preparation area 1 is shown in
Several feed preparation areas 1 or more storages 8, 9 than shown in
Driving route 4 leads past storages 9, 8 in feed preparation area 1, in a presently angled manner. Loading facilities, not shown, can be used for loading robot R. Storage 8 can comprise e.g. three additional bunkers, one e.g. for a large amount of spent grains/sugar beet shred and two mineral dispensers 9 for flours or salts, each with an outlet auger 10.
provided in feed preparation area 1 is a section 4a of the driving route along which a power rail line S1 extends with at least one docking device 6, via which electrically operated robot R is able to dock onto power rail line S1 and then travel along power rail line S1, or undock from power rail line S1 and then move electrically by way of battery B to a section 4d toward stable 2. Robot R is in feed preparation area 1 presently standing or driving to storage 9 in order to there be loaded by way of a supply device or output auger 10. Of robot R, a container 30 is visible and at least one current collector 29 for the electrical connection to power rail line S1. The power transmission to robot R can be galvanic, e.g. with a sliding contact, and two current collectors 29, or alternatively contactless by way of induction. Furthermore,
Indicated in stable 2 as a non-restricting example are three feeding lanes 7 substantially parallel to each other, and a longitudinal end-to-end feeding lane 7 in stable 3 The livestock to be fed can stand on both sides of the respective feeding lane 7, or on one side.
In addition to power rail line S1 in feed preparation area 1 in stable 2, further power rail lines S2, S3 and S4 are installed in
As mentioned, further power rail lines S2, S3, S4 and S5 are options and not necessarily required. Alternatively, further power rail lines can be installed in other external storages or facilities of the system (not shown), such as silos or the like, i.e. not in open terrain, but at or in given structures, and each be installed with at least one docking device.
The driving operation of robot R in sections, for example, 4d, 4e and over a portion of sections 4f and 4g is effected by battery B, whereas the supply form the grid can be provided in the illustrated embodiment along power rail lines S2, S3, S4 and S5. When supplying power from the grid, battery B can be continuously topped up or fully charged. It is of course possible to equip robot R with several batteries B. Furthermore, system A can use more than one robot R which can either travel one behind the other or cross each other.
It is also conceivable not to let robot R travel back from the end of feeding lane 7 in stable 3, as shown in the embodiment, but it would then be possible to provide a further section of driving route 4 so that the robot returns from stable 3 directly to feed preparation area 1.
The longitudinal sectional view of feeding robot R in
Feeding robot R further comprises a dispensing device 28, for example, at least one slide arranged laterally on container 30 for closing and exposing a dispensing opening and one or more cross conveyor belts. In order to operate in an energy-efficient manner when dispensing in respective feeding lane 7, only one mixing element may be driven initially for dispensing when a container 30 is full (sampled by weight or filling sensors), while the other mixing element is stopped and only switched on when the filling level decreases in order supply the other mixing element while it continues dispensing or is temporarily stopped. If enough feed has been shifted, the mixing element presently not dispensing can again be shut down. In this manner, various methods for driving the mixing elements and possibly the dispensing device are possible, namely with regard to saving as much electrical energy as possible without impairing the dispensing operation.
The embodiment of feeding robot R shown in
Feeding robot R in
The at least one battery B is a high-voltage battery which due to system requirements is theoretically capable of delivering a DC current higher by a factor of >1, namely 1.41, presently at about 564 V, from the 400 VAC three-phase current.
Furthermore, a safety circuit is indicated as 11 in
As long as feeding robot R is in
Robot R drives autonomously, is automatically loaded, for example, mixes the feed during the dwelling time in feed preparation area 1, or even when visiting the respective feeding lane, and dispenses the feed for the livestock according to predetermined programming. If power rail line S1 is installed only in feed preparation area 1, then the driving operation and the dispensing takes place using battery B, however, if several power rail lines S1 to S5 are installed in the system, each with at least one docking device 6 except for the driving sections in open terrain as indicated for example in
The circuit of feeding robot R shown in
Feeding robot R carrying out the mixing and/or cutting operation with three-phase current was explained with reference to
Number | Date | Country | Kind |
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202017104377.0 | Jul 2017 | DE | national |