WO2013141796A1

WO2013141796A1 - Scheduling of maintenance

Info

Publication number: WO2013141796A1
Application number: PCT/SE2013/050295
Authority: WO
Inventors: Tony Lindgren; Anna Pernestål
Original assignee: Scania Cv Ab
Priority date: 2012-03-20
Filing date: 2013-03-19
Publication date: 2013-09-26
Also published as: EP2828808A1

Abstract

A planning entity for scheduling a motor vehicle's maintenance visits to a workshop includes: an input interface (110), a proces- sor (120) and an output interface (130). The input interface (110) receives utilization data (UD) representing how the motor 5 vehicle has been used during a data collection period. The utili- zation data (UD) contains a predefined set of condition factors (d1, d2, …, dx). Based on the utilization data (UD) and at least one weight factor (w1, w2, …, wx) associated to each condition factor in the predefined set of condition factors (d1, d2, …, dx), 10 the processor (120) derives a respective maintenance interval (M-INT1, M-INT2, …, M-INTn) for at least one maintenance ins- tance (MI1, MI2, …, MIn) in respect of the motor vehicle. The weight factor (w1, w2, …, wx) reflects how the condition factor (d1, d2, …, dx) to which it is associated influences the wear of 15 at least one component being the subject of a given maintenan- ce instance (MI1, MI2, …, MIn). Based on the at least one main- tenance interval (M-INT1, M-INT2, …, M-INTn), the processor (120) presents a maintenance program (MP) via the output inter- face (130). The maintenance program (MP) describes recom-20 mended visits to a workshop.

Description

Scheduling of Maintenance

TH E BACKG ROU N D OF TH E I NVENTION AN D P RIOR ART

The present invention relates generally to scheduli ng of mai ntenance for motor vehicles. More particularly the invention relates to a planning entity according to the preamble of claim 1 . The invention also relates to a method according to the preamble of claim 8, a computer prog ram according to claim 1 5 and a computer program product accordi ng to claim 1 6.

Service and mai ntenance of mechanical equipment has been needed as long as such equipment has existed . Moreover, especially for motor vehicles i n commercial use, (e.g . trucks and busses) , it is interesting to minimize the downtime, i.e. when the vehicle cannot be used (for example because it is in a workshop for mai ntenance). Hence, there is a balance between the requi- rement to perform maintenance in order to maxi mize the useful lifespan , and the wish to avoid un necessary workshop visits. Historically, tests and theoretical models have been employed to accomplish relevant maintenance programs for different types of products, such as motor vehicles. Within the vehicle industry, it has been common practice to assign intervals for when mai ntenance shall be performed , and which measu res that shall be taken at each maintenance occasion . For i nstance, a given maintenance occasion may be of smaller type (when only relatively few measures are taken) , or larger type (when comparatively many measu res are taken) . Depending on how much the vehicle is expected to be used and the owner's demand for availability, the dates for the smaller and larger maintenance occasions are assigned. However, such a static maintenance schedule is problematic because the use conditions may change dramatically du ring the lifespan of the vehicle. Consequently, workshop visits may occu r too frequently or too seldom relative to when maintenance is actually needed. Moreover, since it is generally desired to keep the nu mber of workshop visits low, a nu mber of maintenance instances must always be scheduled to a common point in time, which is deter- mined by the shortest maintenance interval for the mai ntenance instances concerned. Hence, in respect of all other maintenance instances except the maintenance instance associated with the shortest interval, the workshop visit actually comes too soon. US 4,525,782 and US 6,370,454 describe examples of solutions where a mai ntenance schedule for a motor vehicle (or other mechanized equipment) is adapted based on the actual use of the vehicle/equipment.

US 201 0/0087985 discloses a solution for collecting and recor- ding details relating to the operation of a vehicle under adverse conditions. The recorded data is particularly useful to forestall catastrophic failures, and to provide valuable information for potential buyers of used vehicles. Among the operating conditions that are considered are hig h levels of air contaminants, opera- tion i n extreme hot or cold temperatures, hauling heavy loads, as well as hard braking, tu rning and acceleration . I n addition to the detection and recording of data, prorated mai ntenance schedules are recalculated and adjusted to accommodate for the operation of the vehicle under these adverse or less than ideal conditions. Typically, the data is stored in the on-board computers present in most vehicles. Periodic off loadi ng of the data to the dealer and service providers is also provided .

US 201 0/0023209 reveals a method of organizing ai rcraft maintenance. Here, a recommended maintenance prog ram is defined for an aircraft, where maintenance deadlines for the recommended mai ntenance program are determined by using pri mary data from testing pieces of equipment and/or elements of the aircraft. Utilization data for the aircraft is used and stored. A calculation device implements at least one algorith m to recalculate the maintenance deadlines as a function of the actual utilization data. The recom mended maintenance prog ram is then updated.

P ROBLEMS ASSOC IATE D WITH TH E PRIOR ART

Thus various solutions are known for recording utilization data for a motor vehicle, and based on the recorded data, adapt a maintenance plan for the vehicle and/or adjust other arrangements where use factors are relevant. However, there is still room for improvements in terms of the accu racy of these adaptations. SUMMARY OF TH E I NVENTION

The object of the present invention is therefore to provide a solution, which offers maintenance scheduling with improved precision relative to when maintenance is actually requi red, such that the frequency of u n necessary workshop visits is reduced. According to one aspect of the invention , the object is achieved by the initially described planning entity, wherein the utilization data contains a predefined set of condition factors. The processor is also configured to compute the at least one maintenance interval on the further basis of at least one weight factor asso- ciated to each condition factor in the predefined set of condition factors. Here, the weig ht factor reflects how the condition factor to which it is associated influences the wear of at least one component being the subject of a given maintenance instance.

This planning entity is advantageous because by the proposed weig hting of the condition factors it is possible to attain very hig h precision in how each condition factor influences the maintenance intervals for the individual components of the motor vehicle. Thus, the maintenance program can be made especially relevant for each vehicle. According to one embodiment of this aspect of the invention, the maintenance interval is expressed in terms of an operating time and/or a distance driven by the motor vehicle. The processor is fu rther configured to compute the mai ntenance interval based on the condition factors, such that the maintenance interval is either decreased or increased from a nominal value depending on whether the data reflected by a particular condition factor is expected to intensify or reduce the wear of a component being the subject of the maintenance instance. Thereby, the mai ntenance interval can be given a highly precise extension i n time. According to another embodiment of this aspect of the invention, the processor is configu red to compute the maintenance interval on the fu rther basis of the at least one weig ht factor, such that the influence of a particular condition factor on a given mai nte- nance instance is either raised or lowered depending on whether the condition factor is deemed to be relatively important or relatively unimportant for the wear of the component being the subject of the mai ntenance instance. Thereby, different correlations between the condition factors and various maintenance instan- ces can be modeled adequately.

According to yet another embodiment of this aspect of the invention, the maintenance interval is associated with a minimal value below the nominal value and a maximal value above the nominal value. Here, the minimal and maximal values express a shortest and a longest recommended interval respectively between two consecutive visits to the workshop in the maintenance prog ram. Preferably, the processor is configured to assig n the maintenance interval to the minimal value if, based on the condition factors and weig ht factors, the maintenance interval is computed to a value below the minimal value. Analogously, the processor is preferably configu red to assign the maintenance interval to the maxi mal value if, based on the condition factors and weight factors, the maintenance interval is computed to a value above the maximal value. Thereby, the maintenance inter- val will be kept withi n predefi ned limits even if the vehicle is subjected to extreme use conditions. This, in tu rn , is beneficial from a predictability point-of-view.

According to still another embodiment of this aspect of the invention, the condition factors express : a weig ht of the motor ve- hide, a d river's d riving behavior, topog raphic data, traffic conditions, road conditions and/or climate conditions in an environment where the motor vehicle has been operated du ri ng the data collection period . As a result, the key aspects for planning the maintenance can be modeled with high accuracy. According to a further embodiment of this aspect of the invention, the input interface is configured to collect the utilization da- ta via at least one communication network having a wireless interface towards the motor vehicle. Consequently, the maintenance entity may be located in a central node, and be arranged to produce respective maintenance programs for the individual vehicles in a fleet of vehicles.

According to another aspect of the invention , the object is achieved by the method described initially, wherein the utilization data contains a predefined set of condition factors. Additionally, the method involves computing the at least one maintenance inter- val on the further basis of at least one weig ht factor associated to each condition factor in the predefined set of condition factors. Here, the weight factor reflects how the condition factor to which it is associated influences the wear of at least one component being the subject of a given maintenance instance. The advantages of this method , as well as the preferred embodiments thereof, are apparent from the discussion hereinabove with reference to the proposed planning entity.

According to a further aspect of the invention the object is achieved by a computer prog ram loadable into the internal me- mory of a computer, comprising software for controlling the above proposed method when said program is run on a computer.

According to another aspect of the invention the object is achieved by a computer prog ram product, having a prog ram recorded thereon, where the prog ram is to make a computer control the above proposed method.

BRI E F D ESC RI PTION OF TH E D RAWINGS

The present invention is now to be explained more closely by means of embodiments, which are disclosed as examples, and with reference to the attached drawings. Figure 1 shows a block diagram over a planning entity according to one embodiment of the invention, and

Figure 2 shows a flow diagram illustrating the general method accordi ng to the invention. DESCRIPTION OF EMBODIMENTS OF THE INVENTION

We refer initially to Figure 1 showing a block diagram over a proposed planning entity for scheduling a motor vehicle's maintenance visits to a workshop. The planning entity includes an input interface 110, a processor 120 and an output interface 130.

The input interface 110 is configured to receive utilization data UD representing how the motor vehicle has been used during a data collection period. Specifically, the utilization data UD contains a predefined set of condition factors d1, d2, dx. Accor- ding to one embodiment of the invention the condition factors d1, d2, dx may express the actual weight of the motor vehicle during the data collection period; or if the weight has varied, respective actual weights of the motor vehicle during each of a number of intervals within this period (preferably factored by the relative duration of each interval). Alternatively, or as a complement, the condition factors d1, d2, dx may also express a driver's driving behavior during the data collection period, topographic data, traffic conditions, road conditions and/or climate conditions reflecting an environment wherein the motor vehicle has been operated during the data collection period. The data collection period may have any extension in time suitable for the implementation. Thus, the data collection period may be relatively short, say 24 hours, or relatively long, say six months depending what is deemed to be appropriate with regard to the ve- hide and its expected usage.

The processor 120 is configured to derive a respective maintenance interval M-INT1, M-INT2, M-INTn for at least one maintenance instance MM , MI2, Mln of the motor vehicle.

The maintenance intervals M-INT1, M-INT2, M-INTn may be arranged in a listing 150 in the processor 120. A maintenance interval M-INT for a maintenance instance MM is the time between two consecutive maintenance occasions for a component in the motor vehicle. Thus, if a first maintenance instance MM is represented by the oil filter, a first maintenance interval M-INT1 reflects the interval from installing a new oil filter until this filter must be replaced. The maintenance intervals M-INT1, M-INT2, M-INTn are derived based on the utilization data UD. Particularly, the processor 120 is configured to compute the maintenance intervals M-INT1, M-INT2, M-INTn based on the condition factors d1, d2, dx and at least one weight factor w1, w2, wx associated to each condition factor in the predefined set of condition factors d1, d2, dx. The weight factors w1, w2, wx are preferably stored in a data storage 140 accessible by the processor 120, and each weight factor reflects how the condition factor to which it is associated influences the wear of at least one component being the subject of a given maintenance instance MM, MI2, Mln.

Based on the at least one maintenance interval M-INT1, M-INT2, M-INTn, the processor 120 is also configured to set up a maintenance program MP describing recommended visits to a workshop. The output interface 130 is configured to present the maintenance program MP, for instance via a display, in the form of a document (electronic and/or in the form of a print-out) and/ or as an e-mail or any other type of electronic message to one or more predefined recipients. According to embodiments of the invention, the maintenance interval M-INT1, M-INT2, M-INTn is expressed in terms of an operating time and/or a distance driven by the motor vehicle. The processor 120 is further preferably configured to compute the maintenance interval M-INT1, M-INT2, M-INTn based on the condition factors d1, d2, dx, such that the maintenance interval M-INT1, M-INT2, M-INTn is either decreased/shortened or increased/prolonged from a nominal value depending on whether the data reflected by a particular condition factor is expected to intensify or reduce the wear of a component being the subject of the maintenance instance MM, MI2, Mln. For example, the respective correlations between the condition factors d1, d2, dx and the maintenance intervals M-INT1, M- INT2, M-INTn are assigned manually by an expert who enters his/her knowledge into a computer program comprising soft- ware for controlling the processor 120.

It also advantageous if the processor 120 is configured to com- pute each maintenance interval M-INT1, M-INT2, M-INTn on the further basis of the at least one weight factor w1 , w2, wx, such that the influence of a particular condition factor d1, d2, dx on a given maintenance instance MM, MI2, Mln is either raised or lowered depending on whether the condition factor is deemed to be relatively important or relatively unimportant for the wear of the component being the subject of the maintenance instance MM, MI2, Mln. Analogous to the above, the weight factors w1 , w2, wx may be assigned manually by an expert in the form of parameters in a computer program for controlling the processor 120. Here, the expert assigns the weight factors w1 , w2, wx based on empirical knowledge about relationships between the condition factors d1, d2, dx and the maintenance instances MM, MI2, Mln. Preferably, each maintenance interval M-INT1, M-INT2, M- INTn is associated with a minimal value and a maximal value. The minimal value represents a value below the nominal value for the maintenance interval M-INT1, M-INT2, M-INTn, and correspondingly, the maximal value represents a value above the nominal value. The minimal and maximal values express a shortest and a longest recommended interval respectively between two consecutive visits to the workshop in the maintenance program MP. I.e. the minimal and maximal values may be expressed in terms of driving distance and/or operating time for the motor vehicle.

In practice, the minimal and maximal values may be used as follows. If, based on the condition factors d1, d2, dx and weight factors w1, w2, wx, a given maintenance interval M-INT1, M- INT2, M-INTn is computed to a value below the minimal va- lue, the processor 120 is configured to assign the maintenance interval M-INT1, M-INT2, M-INTn to the minimal value. Analogously, if, based on the condition factors d1, d2, dx and weight factors w1, w2, wx, a given maintenance interval M- INT1, M-INT2, M-INTn is computed to a value above the maximal value, the processor 120 is configured to assign the maintenance interval M-INT1, M-INT2, M-INTn to the maximal value. Thus, also under extreme use conditions, the mainte- nance program M P will contai n reasonable maintenance intervals.

According to one embodiment of the invention, the input interface 1 1 0 is connected to at least one commu nication network, which, in tu rn, has at least one wireless interface towards the motor vehicle. The input interface 1 1 0 is further configu red to collect the utilization data U D via the at least one interface, preferably wi reless. Consequently, utilization data U D in respect to a large number of vehicles may be fed into the processor 1 20 in very convenient manner.

The above procedu re implemented by the processor 1 20 is preferably controlled by a computer prog ram loaded into a memory 1 60 of the processor 1 20, or an external memory unit accessible by the processor 1 20 (not shown) . The computer prog ram, in tu rn, contains software for controlling the steps of the procedu re when the prog ram is ru n on the processor 1 20.

In order to su m up, the general method of scheduli ng a motor vehicle's maintenance visits to a workshop according to the invention will be described below with reference to the flow dia- gram in figu re 2.

In a first step 21 0, it is checked if utilization data have been received , and if so, a step 220 follows. Otherwise, the procedu re loops back and stays in step 21 0. The utilization data are presumed to contai n a predefined set of condition factors representing how the motor vehicle has been used duri ng a data collection period.

In step 220 the received condition factors are retrieved , where after in a step 230, a respective maintenance interval is computed for at least one maintenance instance of the motor vehicle. Specifically, the maintenance intervals are derived based on the condition factors and a respective weig ht factor associated to each condition factor. Here, a given weight factor reflects how the condition factor to which it is associated influences the wear of at least one component being the subject of a particular maintenance. Subsequently, a maintenance program is presented in a step 240. The maintenance prog ram describes recommended visits to a workshop, and is based on at least one of the mai ntenance intervals computed in step 230. Then, the procedu re ends.

The process steps, as well as any sub-sequence of steps, described with reference to the figure 2 above may be controlled by means of a programmed computer apparatus. Moreover, although the embodiments of the invention described above with reference to the drawings comprise computer apparatus and processes per- formed in computer apparatus, the invention thus also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of source code ; object code, a code intermediate source and object code such as in partially compiled form, or in any other form suitable for use in the implementation of the process according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a Flash memory, a ROM (Read Only Memory), for example a CD (Compact Disc) or a semiconductor ROM, an EPROM (Erasable Programmable Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), or a magnetic recording medium, for example a floppy disc or hard disc. Further, the carrier may be a transmissible carrier such as an electrical or optical signal, which may be conveyed via electrical or optical cable or by radio or by other means. When the program is embodied in a signal, which may be conveyed , directly by a cable or other device or means, the carrier may be constituted by such cable or device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted for performing, or for use in the performance of, the relevant processes.

The invention is not restricted to the described embodiments in the figures, but may be varied freely within the scope of the claims.

Claims

1. A planning entity for scheduling a motor vehicle's maintenance visits to a workshop, the planning entity comprising:

an input interface (110) configured to receive utilization data (UD) representing how the motor vehicle has been used during a data collection period,

a processor (120) configured to, based on the utilization data (UD), derive a respective maintenance interval (M-INT1, M- INT2, M-INTn) for at least one maintenance instance (MM, MI2, Mln) in respect of the motor vehicle, and

an output interface (130) configured to present a maintenance program (MP) describing recommended visits to a workshop, which maintenance program (MP) is based on said at least one maintenance interval (M-INT1, M-INT2, M-INTn), characterized in that

the utilization data (UD) comprises a predefined set of condition factors (d1, d2, dx), and

the processor (120) is configured to compute the at least one maintenance interval (M-INT1, M-INT2, M-INTn) on the further basis of at least one weight factor (w1 , w2, wx) associated to each condition factor in the predefined set of condition factors (d1, d2, dx), the weight factor reflecting how the condition factor to which it is associated influences the wear of at least one component being the subject of a given maintenance instance (MM, MI2, Mln).

2. The planning entity according to claim 1, wherein the at least one maintenance interval (M-INT1, M-INT2, M-INTn) is expressed in terms of at least one of an operating time for the motor vehicle and a distance driven by the motor vehicle, and the processor (120) is configured to compute the at least one maintenance interval (M-INT1, M-INT2, M-INTn) based on the condition factors (d1, d2, dx) such that the maintenance interval (M-INT1, M-INT2, M-INTn) is either decreased or increased from a nominal value depending on whether the data reflected by a particular condition factor is expected to intensify or reduce the wear of a component being the subject of the maintenance instance (MM, MI2, Mln).

3. The planning entity according to claim 2, wherein the processor (120) is configured to compute the at least one maintenance interval (M-INT1, M-INT2, M-INTn) on the further basis of the at least one weight factor (w1 , w2, wx) such that the influence of a particular condition factor on a given maintenance instance (MM, MI2, Mln) is either raised or lowered depending on whether the condition factor is deemed to be relatively important or relatively unimportant for the wear of the component being the subject of the maintenance instance (MM, MI2, Mln).

4. The planning entity according to any one of claims 2 or 3, wherein the at least one maintenance interval (M-INT1, M-INT2,

M-INTn) is associated with a minimal value below the nominal value and a maximal value above the nominal value, the mi- nimal and maximal values expressing a shortest and a longest recommended interval respectively between two consecutive visits to the workshop in the maintenance program (MP).

5. The planning entity according to claim 4, wherein the processor (120) is configured to:

assign the at least one maintenance interval (M-INT1, M-

INT2, M-INTn) to the minimal value if, based on the condition factors (d1, d2, dx) and weight factors (w1 , w2, wx), the at least one maintenance interval (M-INT1, M-INT2, M-INTn) is computed to a value below the minimal value, and

assign the at least one maintenance interval (M-INT1, M-

INT2, M-INTn) to the maximal value if, based on the condition factors (d1, d2, dx) and weight factors (w1 , w2, wx), the at least one maintenance interval (M-INT1, M-INT2, M- INTn) is computed to a value above the maximal value.

6. The planning entity according to any one of the preceding claims, wherein the condition factors (d1, d2, dx) express at least one of: a weight of the motor vehicle, a driver's driving behavior, topographic data, traffic conditions, road conditions and climate conditions in an environment where the motor vehicle has been operated during the data collection period.

7. The planning entity according to any one of the preceding claims, wherein the input interface (110) is configured to collect the utilization data (UD) via at least one communication network having a wireless interface towards the motor vehicle.

8. A method of scheduling a motor vehicle's maintenance visits to a workshop, the method comprising:

receiving utilization data (UD) representing how the motor vehicle has been used during a data collection period, and

deriving, based on the utilization data (UD), a respective maintenance interval (M-INT1, M-INT2, M-INTn) for at least one maintenance instance (MM, MI2, Mln) in respect of the motor vehicle, and

presenting a maintenance program (MP) describing recommended visits to a workshop, which maintenance program (MP) is based on said at least one maintenance interval (M-INT1, M- INT2, M-INTn),

characterized by the utilization data (UD) comprising a predefined set of condition factors (d1, d2, dx), and the method comprising:

computing the at least one maintenance interval (M-INT1,

M-INT2, M-INTn) on the further basis of at least one weight factor (w1 , w2, wx) associated to each condition factor in the predefined set of condition factors (d1, d2, dx), the weight factor reflecting how the condition factor to which it is asso- ciated influences the wear of at least one component being the subject of a given maintenance instance (MM, MI2, Mln).

9. The method according to claim 8, wherein the at least one maintenance interval (M-INT1, M-INT2, M-INTn) is expressed in terms of at least one of an operating time for the motor vehicle and a distance driven by the motor vehicle, and the method comprising computing the at least one maintenance interval (M-INT1, M-INT2, M-INTn) based on the condition factors (d1, d2, dx) such that the maintenance interval (M-INT1, M- INT2, M-INTn) is either decreased or increased from a nominal value depending on whether the data reflected by a particular condition factor is expected to intensify or reduce the wear of a component being the subject of the maintenance instance (MM, MI2, Mln).

10. The method according to claim 9, comprising computing the at least one maintenance interval (M-INT1, M-INT2, M- INTn) on the further basis of the at least one weight factor (w1, w2, wx) such that the influence of a particular condition factor on a given maintenance instance (MM, MI2, Mln) is either raised or lowered depending on whether the condition factor is deemed to be relatively important or relatively unimportant for the wear of the component being the subject of the maintenance instance (MM, MI2, Mln).

11. The method according to any one of claims 9 or 10, wherein the at least one maintenance interval (M-INT1, M-INT2, M-INTn) is associated with a minimal value below the nominal value and a maximal value above the nominal value, the minimal and maximal values expressing a shortest and a longest recommended interval respectively between two consecutive visits to the workshop in the maintenance program (MP).

12. The method according to claim 11, comprising:

assigning the at least one maintenance interval (M-INT1,

M-INT2, M-INTn) to the minimal value if, based on the condition factors (d1, d2, dx) and weight factors (w1 , w2, wx), the at least one maintenance interval (M-INT1, M-INT2, M- INTn) is computed to a value below the minimal value, and

assigning the at least one maintenance interval (M-INT1,

M-INT2, M-INTn) to the maximal value if, based on the condition factors (d1, d2, dx) and weight factors (w1, w2, wx), the at least one maintenance interval (M-INT1, M-INT2, M-INTn) is computed to a value above the maximal value.

13. The method according to any one of claims 8 to 12, wherein the condition factors (d1, d2, dx) express at least one of: a weight of the motor vehicle, a driver's driving behavior, topographic data, traffic conditions, road conditions and climate conditions in an environment where the motor vehicle has been operated during the data collection period.

14. The method according to any one of claims 8 to 13, comprising collecting the utilization data (UD) via at least one communication network having a wireless interface towards the mo- tor vehicle.

15. A computer program loadable into the internal memory of a computer, comprising software for controlling the steps of any of the claims 8 to 15 when said program is run on the computer.

16. A computer program product (160), having a program recorded thereon, where the program is to make a computer control the steps of any of the claims 8 to 15.