SE531406C2 - Method and arrangement for automatic truck system - Google Patents

Abstract

The present invention is related to a driverless truck system comprising at least one traction vehicle (A) with a guiding system (6, 11) arranged to be able to follow a line- shaped marking (C) arranged on the ground, which traction vehicle (A) comprises a chassis (1), a propulsion system (2), a control unit (4), safety arrangements (5), a superstructure (7) and at least one common 12 or 24 volt battery (1OA, 10B) as energy source, said propulsion system (2) utilising two drive wheels (200, 201) arranged to be able to be driven by one electric motor each (204, 205), independently of each other, said guiding system (6, 11) comprises a sensor part (6) with multiple sensors (601 A- 601G) positioned in the lateral direction of the vehicle and arranged to be able to produce a signal image by aid of which the relative position of the vehicle in relation to the centre line (Cc) of said line-shaped marking (C) can be determined, the same number of signal transmitting units (602A-602G) preferably being used.

Description

535 405 functionality in each subsystem to meet different types of requirements set by potential users.

Many of these known, modified systems focus on being able to reduce / reduce the cost of the drive system and then above all the cost of batteries. By US 2004 / 025,187 and US 6,498,454, prior art systems which are intended to optimize the charging process of batteries for such systems are thereby able to keep the cost at a lower level. However, this type of system has not sufficiently led to cost reduction as a whole.

Other known alternatives have focused on trying to create cheaper control systems. By US 6,341,430, Lex. previously known an alternative where the control system uses a special kind of coding for controlling an AGV. As above, however, this system also does not lead to any major cost reduction from a holistic perspective.

JP 2005018248 discloses another modification where one also tries to solve the cost problem by means of the control system, by using a control system with a plurality of deployed signal stations intended to guide the driverless trucks.

JP 2000309276 shows another known attempt to reduce costs, in which case it is proposed to use a special type of semi-trailer vehicle that will enable energy-saving lifting and moving.

JP 2005088814 discloses another system in which, in order to reduce the cost, it is proposed to use driverless trucks whose lifting and towing capacity are limited and in which subsystems with limited functionality are used. However, this system also has many disadvantages, e.g. an inability in the control system, and a relatively expensive control system.

Furthermore, a concept is known through JP 2001175331 where the focus is on using compact and cheap driverless trucks with subsystems that are relatively cheap. It is proposed to use relatively cheap 12-volt batteries as a drive source, use of a relatively small vehicle chassis with relatively low weight, use of a drive system with relatively limited traction, a relatively simple steering / control system with limited functionality and a relatively simple tracking system that uses tape instead. for more expensive erings xering / driver enrichment methods. The use of tape allows the opportunity to keep low cost in relation to many of the other known concepts for controlling such trucks. However, the system according to JP 20001 175331 shows a great disadvantage as it only 531 4138 enables 90-degree turns and straight movements, which drastically reduces the area of use: for the system. In addition, a system according to JP 20001175331 shows other shortcomings, e.g. regarding security aspects, which is probably an explanation for the system not reaching the market, at least not to any real extent.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a method and system which eliminates or at least minimizes some of the above-mentioned disadvantages, which is achieved by means of a driverless truck system according to claim 1.

Thanks to the solution according to the invention, a driverless tm system is provided which with good functionality meets most of the many requirements that the market requires of such a system, at a cost which is significantly less than the cost of existing systems on the market. As an example, it can be mentioned that the purchase price for a driverless truck according to the present invention can be made at a cost reduced by more than 80% compared with a common driverless truck system existing on the market.

According to further aspects of the invention, it applies: - with reference to claims 3 and 4, that the advantage is obtained that automatic parking braking is effected, as well as that braking is obtained automatically by means of the transmission. - with reference to claims 5, 6, 7 that a highly cost-effective solution for obtaining a stable and weight-optimized design can be obtained, which is also rational from a production point of view, - with reference to claims 8 and 9 a very cost-effective and flexible solution for safe and flexible handling of such vehicles, - with reference to claim 10 a further aspect regarding enabling a particularly cost-effective arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention will be described in more detail with reference to the accompanying figures, in which: Fig. 1 shows a side view of parts of a driverless truck according to the invention, and a carriage intended to be towed by such, Fig. 2 shows a perspective view obliquely from above of a driverless truck according to the invention, 531 4GB Fig. 3 shows a plan view seen from below of a driverless truck according to the invention, Fig. 4 shows the same kind of view as Fig. 2, but without the superstructure, Fig. 5 shows a perspective view obliquely from above and obliquely from behind where not only the superstructure but also parts of the supporting frame structure have been removed, to show parts of the transmission according to the invention, Fig. 6 shows the card with IR transmitter and 1R sensor, according to an embodiment of the invention, a guide tape according to the invention is indicated, Figs. Fig. 7 schematically shows the signal reading of the IR sensor when the driverless truck travels in the middle of a guide tape according to the invention, Fig. 8 shows the corresponding signal image when the truck has been moved so that it ends with its center line to the right of the tape center line, and Fig. 9 shows a display unit according to a embodiment of the invention.

DETAILED DESCRIPTION Fig. 1 shows parts of a driverless truck A according to the invention which pulls a trolley B, which is normally used in this transport system. The trolley B is of traditional construction, comprising a load Bl ak B1 arranged with / at a frame construction which is lined with B3. A drawbar B4 is provided with a drawbar for coupling to the driverless truck A. Because the pair of wheels B2, which are connected to the part with drawbar B4, are rotatably arranged at the carriage B, the carriage will follow the movement of the driverless truck. By arranging this in the rear end of the carriage B with a connecting device B5, further carriages can be connected so that a train is formed.

I F ig. 2 shows a view seen obliquely from above of a driverless truck A according to the invention. The figure indicates reference designations which indicate different constituent parts / subsystems of the dry truck A, in order to provide a clear structure for reference designations which will be used later on. Reference numeral 1 refers to the vehicle chassis, with reference numeral 2 to the vehicle's propulsion system / transmission, with reference numeral 3 to the vehicle's towing device, with reference numeral 4 to the vehicle's control panel and associated safety arrangement, with reference numeral automatically come to a stop, with reference number 6 (see Fig. 3) the vehicle's steering / sensor system, with reference number 7 of the vehicle's bodywork / body, with reference number 8 the vehicle's support beam1 directly carried load, with reference number 9 to the vehicle's safety system with respect , with reference numeral 10 to the system's energy source battery system, and finally with reference numeral 11 to the system's automatic control / system. 531 4GB The vehicle is designed to be very compact. According to a preferred embodiment of the invention, the towing vehicle A has a width in the range 75 ~ 90 cm, preferably 80 cm, 5 cm, a total length including drawbar of 100 ~ 140 cm, preferably 120 cm, in 5 cm, a height to the control panel 4 in the range 60 - 80 cm, preferably 70 cm,: h 3 cm, a ground clearance in the range 1 - 5 cm, preferably in the range 1.5 - 3 cm, a wheelbase in the range 45 - 60 cm, preferably in the range 50 - in 3 cm, and a weight including batteries in the range 100 ~ 150 kg, preferably 1 15 - 135 kg. The maximum load on top of the vehicle's load device 8 is suitably in the range 30 ~ 70 kg, preferably 50 kg, in 10 kg, its maximum towing load 400 ~ 600 kg, preferably 500 kg, ä: 50 kg., Its maximum speed in the range 2 - 4 km, preferably ca. 3 km and its maximum speed during a start-up phase in the interval 20 - 50% of the maximum speed.

Fig. 3 shows a bottom view of the vehicle A. It is shown that the chassis 1 is based on a bottom plate 100, which consists of a relatively thick-walled plate, suitably in the range 8 to 12 mm, with a width of approx. 55 cm (preferably in the range 40 - 70 cm) and a length of approx. 90 cm (preferably in the range 70 - 110 cm). The base plate is essentially solid, which means a cost-effective and compact way of obtaining sufficient weight, so that the vehicle can stop quickly, ie. in order to have a relatively high friction between the ground and the wheels 200, 201. Preferably, the bottom plate is given a total weight in the range of 25 kg. to kg. Furthermore, it is shown that the bottom plate 100 is arranged with a number of recesses, e.g. for easy and safe installation of chassis parts welded to the base plate, e.g. a drawer construction 1 10-114 (described in detail in connection with Fig. 4). The total weight of the entire chassis is suitably in the range of 40 - 50 kg.

A recess 101 located centrally with respect to the center line C A of the vehicle and at the front of the base plate 100, is provided to enable transmitter and sensor signals, respectively, to pass through the plate. Arranged at the sensor card 6 (see Fig. 4) is partly an arrangement of transmitter units 602 and partly an arrangement of receiver units 601. In the vicinity of said first recess 101 there is arranged a second recess 102 which is circular, in order to be able to provide a 360- gradual free pivotability to a front support wheel 250, which is mounted centrally around a vertical bearing 251, within the recess 102.

The bearing 251 is in turn fixed to a U-shaped crossbeam 252 recessed in the base plate 100 (preferably all fastenings included in the chassis are welded). The reason why the crossbeam 252 is U-shaped is that the attachment 252 for the wheel 250 should suitably be on a higher level than the plate 100 for is to be able to provide lower clearance. According to a preferred embodiment of the invention, the ground clearance is in the range of 15 ~ 30 cm. 53 'l 405 As is clear from Pig. 3, the vertical pivot axis of the support wheel 250 is arranged at a distance from the center line CA of the vehicle and the sensor device 6, respectively. Thanks to this "non-centered" positioning of the support wheel 250, the wheel will not soil the mark, e.g. tape strip (see Fig. 7), which is used for steering the vehicle A.

It is further shown that at the rear of the vehicle, at its sides, symmetrical recesses 103, 104 are intended to accommodate the drive wheels 200, 201, so that the outer wheel sides are substantially in line with the side edges of the base plate. In addition, there are a number of smaller, groove-shaped recesses 105 made in the base plate 100, in order to enable stable anchoring of various parts to be attached on top of the base plate 100, which is advantageous both from the mounting point of view and the strength point of view. Finally, further recesses 106, 107 are shown in the base plate, which are arranged between the wheels 200, 201, the purpose of which is to provide space for drive motors 204, 205 and transmission 202, 203, respectively, to be able to extend downwards through the base plate. Fig. 4 shows the vehicle A seen in a perspective obliquely from above with the body / superstructure 7 removed. The bumper mechanism 5 is clear here. Its front part 50 consists of a curved sheet metal part with a larger overall width than the rest of the vehicle.

The design is such that cutting or scraping damage simply cannot occur by contact with the front part 50. The front part 50 is at its rear side surface in a first 51 and a second 52 burner bar, respectively, which are slidably arranged in brackets 53, 55.

Thus, the front part 50 with the bumper rods 51, 52 can be moved from its lower position to a position where it abuts the free inner part of the vehicle plate 100 (or the other part) by the rods 51, 52 sliding through the holes provided in said brackets 53. , 55. At the rear end of the respective bumper rod 51, 52 (see also Fig. 5) there is an end surface 56 which is intended to cooperate with a switch unit 57, 58. The switch unit 57, 58 comprises a pivotable switch arm 57, which when it is pivoted away in its unaffected position (in Fig. 4 in its lowered position) the current breaks and thus initiates braking of the drive wheels 201, 202. Preferably, the safety system, in addition to the bumper mechanism 5, is supplemented with an ultrasonic sensor 9.

At the front of the base plate 100 the card 6 with transmitter and sensor units is arranged, which card 6 will be described in more detail in connection with Fig. 6. In direct connection to this place a control and control unit 11 is arranged, in the form of a compact unit, which houses hardware and software to control various functions of the vehicle. Arranged behind this and on top of the bottom plate 100 is the previously mentioned 531 4136 box construction, which consists of two side plates 110, a rear plate 114, an inclined front plate 112 and a top part 111 forming a box, the plate thickness preferably being in the range 2 ~ 5 mm , i.e. substantially thinner than in the plate 100. This box construction 110 - 114 forms a support structure for testing most of the various input load / force absorbing details in the construction, such as e.g. wheels 200, 201, bumper mechanism 5, drive motors 204, 205 and struts 82/84; 83/85 (which are suitably also welded to be included in the chassis) for the loading plate 8. In the upper plate lll fi there are arranged recesses adapted to be able to accommodate two 12-volt batteries 10A, 10B, which are preferably connected in series to be able to use a 24- volt system, i.a. for driving the DC motors 204, 205. 1 Fig. 5 is a perspective view obliquely from above seen from behind to show more clearly the transmission according to this embodiment of the invention. Only the right motor 204 is described here, since the construction is largely exactly the same on both sides.

The motor 204 is positioned so that its rotor axis (not shown) is arranged at an acute angle relative to the horizontal plane of the base plate. The output rotor shaft transmits via a self-braking snow gearbox, housed in a gearbox housing 203. The gear ratio is suitably in the range 4021 - 60: 1, preferably approx. 50: 1, which with a maximum rotation of 3000 rpm on the engine gives a maximum rotation of 60 rpm on the drive wheels 200, 201. The output shaft from the transmission part 203 transmits the rotation to the drive shaft 215 for the wheel arranged coaxially therefor. Transmission part 203 and wheel / axle 215 are fixed to the chassis via axle brackets 211 which are welded in side plate roller 110 (see Fig. 4). It can be noted that the second motor 205 is positioned in reverse with respect to the first motor 204, by interacting with the first nansmission part 202 on its upper side, instead of on the lower side. Reason for this year is that it is desired to have the same driving direction on the motors and thereby, in a simple manner, obtain the desired driving direction on the wheels.

In addition, it can be seen from Fig. 5 that the drawbar 310 is attached to the bottom plate 100 by means of a spacer bracket 312 and that a bolt device 311 is arranged through a hole at its outer end, in order to be able to easily hang on a trolley or the like. As already shown, the main towing device 300 is arranged more centrally in the vehicle. Preferably, its attachment to the base plate 100 is arranged midway between the drive wheel 200, 201, on (or near) the drive shaft line, in order to minimize torque impact when turning. The traction device consists of a rod-shaped part 302 which is fixed to the bottom plate and which extends straight upwards, in order to arrange the connecting part 300 itself at a reasonably high height above the superstructure 7. The connecting part 300 itself is conically shaped so that it is thicker near the top level at which the loop of the drawbar rests. 531 405 This provides "automatically" that the rod does not jump off, e.g. in case of heavy braking. Thanks to this, no extra "locking mechanism" is needed and thanks to choosing a low maximum speed for the vehicle, the gap (as caused by the "thick top") between the towing eye and the coupling part 300 does not create any problems, e.g. in the form of shakes, during operation. In addition, it is shown that the control panel 4 is arranged at an inverted U-shaped structure 140, 141, 142, consisting of two substantially vertically arranged rods 140, 141 (which slope slightly obliquely backwards, so as not to "disturb" placement of other parts or prevent turning). , and which are joined by a flat bar 142 at the top. On top of the flat bar 142, the control panel 4 is arranged in a suitable manner.

A charging contact 143 is arranged in the vicinity of the control panel 4.

Fig. 6 shows a schematic view of the underside of parts of a control card 6 according to the invention and also a tape C, preferably 15-25 mm wide, more preferably approx. 20 mm, to be used for steering the vehicle according to a preferred embodiment. It can be seen that the control board 6 is provided with a transmitter part 602 and a sensor part 601. The transmitter part 602 consists of a plurality of IR diodes 602A-602G, preferably at least 5 pieces, more preferably 7 as shown in the circuit, which are suitably located 10-20. etc. apart. At a tape width of 20 mm, a distance ts of approx. 13 mm is preferred, meaning that a central diode can be centered at the same time as the two adjacent diodes have about one half above the tape and the other half outside the tape C. An equal number of photodiodes 601A-601 G are arranged just behind (preferably in the interval 5 - 10 mm) the transmitter part, which photodiodes constitute a moderating / signal receiving part. It is thus a great advantage that the distance t, between two adjacent IR diodes is less than the width tc of the tape C. Thus, at least two IR diodes will be above the tape at the same time, so that a sufficiently good certainty is obtained in determining the position of the control board 6 and thus the vehicle A in relation to the tape C. Thanks to multiple transmitters / receivers, the relative position of the vehicle in relation to the center line CC of the tape can thus be achieved easily and cost-effectively. The picture shows that the center line G5 for the control board 6 (and thus the vehicle's) is slightly offset in relation to the center line CC of the tape. Furthermore, it appears that the center line one for the control card G6 and the vehicle CA is suitably the same, but it is understood that this is not necessary, since one can easily compensate for a non-centrally positioned control card by programming.

In Figs. 7 and 8 the basic function of the control mechanism according to the invention is illustrated. Fig. 7 shows an example where the control card 6 is centered in relation to the tape C, and Fig. 8 shows an example where the control card (and thus of course the vehicle) is slightly sloping to the right of the center line of the tape. 531 4ÛB The function of the control board is such that IR light is emitted by turning on one of the IR diodes 602A-602G in a sequence. The emitted 1R light emitted via the tape C is measured by the photodiodes 601A-601G, whereby one photodiode is activated at a time and in such a way that when the first IR diode 602A is active, the first photodiode 601A is also active. In a conventional manner, the signals received by the photodiodes are amplified and sent in the form of analog signals for AD conversion and digital processing. The appearance of the analog signal when the sensor is centered at the tape is as shown in Fig. 7 such that the middle analog signal, i.e. the one obtained by the lower photodiode is significantly higher than all the others and that the other signals on each side are successively at a lower level. A kind of stair structure is thus formed, by means of which it can be read that the vehicle A is centered over the tape C. In Figs. 8 instead shows a corresponding signal image when there is a certain offset to the right. On one side of the inner sensor 60lD, a stronger signal image will be obtained so that the stairs become asymmetrical. Using a correction algorithm (preferably in the form of software), the control unit 11 can compensate to the right to reposition the vehicle in a centered manner over the tape C (the same functionality can also be obtained with a digital solution by simply using the signal difference between the channels on each side of the center sensor). Fig. 9 shows a top view of a preferred embodiment of a control panel 4 according to the invention. A keyboard 40, a flash lamp 41, a stop button 42, a reverse drive control button 43, a left-hand drive control 44, a forward drive control button 45 and a right-hand drive button 46 are shown. Safety control unit 11 is preferably programmed so that when the truck starts the flash light 41 starts flashing and a warning signal (sound bar, not shown) sounds. With the help of the emergency stop 42, the truck is started and the battery voltage is broken. The keyboard 40 is intended to be used to initiate different types of functionality of the vehicle A with codes. Thanks to the use of codes, only authorized users are allowed to start the truck. This functionality can also be supplemented, ie. made even more secure, by requiring the submission of a personal code before any control commands can be entered. The truck has a main switch (not shown) which must be activated before the truck can be driven at all. Then it applies that a certain code, xxxx entails starting the vehicle and driving forward. Similarly, another code, yyyy, means that the vehicle stops. An additional code, zzzz, means that a reset is performed by the control system. Another command, pppp is a quick command for turning 180 ° of the drive vehicle A. Calibration of the system is accomplished with yet another code, 531 4GB vvvv. Of course, additional commands can also be supplemented to the above, with other codes.

When driving manually, it is preferably required that the same code, xxxx, must be pressed as for starting the vehicle in combination with the desired arrow key being pressed and held down (dead grip) to drive the truck in the desired direction. To return to automatic mode, one of the keys on the keypad 40 is suitably pressed.

On the control panel there is suitably also a display 46 where battery level, error codes etc. can appear. Appropriately, the battery indicator is arranged to start flashing when it is time for charging.

The dry-free truck A according to the invention is thus a kind of automatic wagon tractor, primarily intended for internal material handling of lighter goods. With the help of the truck, cargo can be transported on wagons B. Thanks to the truck's maneuverability and flexibility, it can be used almost anywhere where wagons of any kind are used today. By using an adhesive tape C, with a suitable reflective upper surface (preferably 3M Scotchlite Diamond GradeTM or the corresponding higher fl rectifying surface is used) and a suitable adhesive backing on the underside, e.g. and acrylic adhesive. The track that the truck is to follow can thus easily be changed and become cheap in iron movement with most other known systems. Thanks to the arrangement of the support wheel not centered, the risk of soiling of the tape C is also minimized. In accordance with what has already been shown, the vehicle A is suitably started manually but arranged to be able to stop automatically at marked terminals. The terminal is suitably marked e.g. by placing three pieces of tape in width, so that a large number of the photodiodes give the same kind of output signal, whereby a bild- from the step pattern clearly deviating signal image is obtained and thus the control unit receives signal / s to stop the vehicle A.

Conveniently, the control unit 11 is programmed with an error tracking function, which means that when the sensor unit 6 loses contact with the tape C, a search for the loop is made automatically, first by searching e.g. 45 ° in the direction from which it came and then once in the opposite direction. If it does not find its way back to loop C then it is suitably programmed to stop. The minimum turning radius for the tape is suitably made to be in the range 1-2 m, preferably approx. 1.5 m, in order to obtain a sufficiently high reliability (Sat to avoid derailment) with at the same time good cost efficiency regarding the sensor system. The unit is programmed so that the keyboard 40 is only allowed to cut off the control current to the motor control and that the emergency stop 42 cuts off the power from the batteries. Of course, the main switch also disconnects the power from the batteries. 531 405 ll When the truck is started (see above) with the keyboard, a control program is preferably activated before driving can be performed, a control program where the user is asked via the display to test / activate burnper and ultrasonic sensor in turn before the truck can be driven away. Furthermore, the device is suitably programmed to have a certain delay, preferably 1-3 seconds before the truck starts to move forward after the starting combination has been depressed. Furthermore, it is appropriate that the truck during a first part-time, e.g. 3 - 7 seconds move at a significantly lower speed than the maximum speed, e.g. 1 km / h during the said part-time before the vehicle A is allowed to go up to full speed of e.g. 3 wages / h. In addition, it is programmed in such a way that the flashlight 41 always flashes when the truck is in motion, which gives a clear indication to people around to look out. Suitably, a special kind of sound signal is also used during the start-up phase itself, Lex. double warning signals, while another type of warning signal (eg single warning signal) sounds when the truck has entered its continued state.

The invention is not limited by what is described above but can be varied within the scope of the appended claims. In addition, many of the subsystems described may be subject to their own patent protection, as it is recognized that they may involve technically efficient solutions in other contexts as well. Thus, for example. that the steering system described above does not necessarily have to be connected to the use in connection with an automatic truck as above and not in all situations a truck with equally rigorous safety systems, e.g. when the trucks move in an environment where people are not allowed to be. In such circumstances it is understood that e.g. a bumper mechanism does not need to be used. Thus, it is understood that the bumper mechanism is not a necessary combination for many of the subsystems described above and which are connected to the bumper mechanism in the subclaims. Due to this, the right to submit separate applications for many of these described subsystems is reserved, without connection to a bumper mechanism. In addition, the person skilled in the art realizes that there are very many obvious mechanical resp. electronics alternative constructions that can be used as an alternative to the above-described, mechanical resp. electronic constructions that the person skilled in the art can use without effort and still use the basic functionality in accordance with the invention. In other words, it is understood that the grain binding solution described according to the invention and the good technical effect it offers, not least in terms of cost reduction, can be obtained with certain different partial solution axes which constitute obvious alternatives for those skilled in the art once the skilled arm has taken part in the overall concept. One such obvious departure is to use a different kind of sensor mechanism and 531 4GB instead of reflective tape for example. use magnetic tape in combination with inductive sensors.

Claims (1)

10 15 20 25 30 35 531 405 13 PATENT REQUIREMENTS Driverless truck system, comprising at least one vehicle (A) with a control system (6, 11) arranged to be able to follow a linear marking (C) arranged on the ground, which vehicle (A) comprises a chassis (1), a propulsion system (2 ), an operating unit (4), safety arrangement (5), superstructure (7) and at least one, battery (10A, 10B) as energy source, said propulsion system (2) using two drive wheels (200, 201) arranged to independently can each be driven by a motor (204, 205), said safety arrangement comprising a bumper mechanism (5) comprising a bumper portion (50, 51, 52) movably arranged at the vehicle (A) between an outer position and an inner position, which bumper mechanism (5) is arranged to activate braking of the vehicle (A) when the movable bumper portion (50, 51, 52) is displaced from its outer position, characterized in that said vehicle (A) is a towing vehicle provided with towing device (300), that the at least one battery (10A, 10B) is a v occurring, 12- or 24-volt, that the distance between the inner and outer position of said bumper mechanism (5) is between 80 - 200 mm, more preferably approx. 90 - 150 mm, and that said traction device (300) is arranged between said drive wheels (200, 201). Driverless truck system according to claim 1, characterized in that said drawbar (300) is arranged on or near, the drive shaft line. . Driverless truck system, according to claim 1 or 2, characterized in that said propulsion system (2) is arranged to be able to provide sufficient braking force fi via the drive wheels (200, 201) to be able to achieve a standstill on flat ground before the movable bumper portion reaches said inner position for a maximum loaded crew, wherein the maximum load is in the range 300 - 800 kg, preferably at least 400 kg, more preferably at least 500 kg. . Driverless truck system according to claim 3, characterized in that said propulsion system (2) comprises a transmission which is self-braking, is in the form of a worm gear (203) with a gear ratio in the range 20: 1- 100: 1, more preferably at least 30: l and most treaty in the interval 40: 1- 60: 1.. Driverless truck system according to any one of the preceding claims, characterized in that said chassis (1) comprises a bottom plate (100) consisting of a plate arranged to directly and / or indirectly form a fastening base for the inner part of, preferably all , load - bearing structures included in the vehicle (A) -. Driverless truck system according to claim 5, characterized in that said base plate (100) is arranged to supply the vehicle with sufficient weight to achieve the desired friction between drive wheels (200, 201) and the ground. . Driverless truck system according to claim 6, characterized in that said bottom plate (100) has a thickness of 8-12 mm, preferably with a weight of 25-35 kg. . Driverless truck system according to one of the preceding claims, characterized in that the towing vehicle (A) itself is arranged with a loading device (8) for a maximum load in the range of 30-70 kg. . Driverless truck system according to any one of the preceding claims, characterized in that said propulsion system (2) is arranged to give an axle speed in the range 2-4 km / h. lO. Driverless truck system according to any one of the preceding claims, characterized in that a support wheel (250, 251) arranged in a longitudinally displaceably displaced, horizontally pivotally arranged position relative to said drive wheel (200, 201), whereby three contact points are obtained, preferably said support wheels (25 0, 251) are positioned a non-dirty said linear marking (C).