GB2188452A

GB2188452A - Programmed electronic controller

Info

Publication number: GB2188452A
Application number: GB08705493A
Authority: GB
Inventors: Helmut Fennel
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co oHG
Priority date: 1986-03-29
Filing date: 1987-03-09
Publication date: 1987-09-30
Anticipated expiration: 2007-03-09
Also published as: FR2596712A1; JPS62233803A; DE3610620A1; GB8705493D0; FR2596712B1; DE3610620C2; GB2188452B

Abstract

A programmed electronic controller, e.g. for vehicle slip control, comprises at least one microprocessor or microcomputer (1, 2) with internal and/or external memory storing a universal programme which can be adapted to different applications and/or designs, e.g. different brake system parameters or different vehicles. An adapter circuit, for instance a coder network (12) and switch network (13) which can be coded by breaking connections (15-18) when the controller is manufactured allows the controller to be customised for a particular application by suitably adapting the universal programme. In controllers containing more than one microprocessor or microcomputer (1, 2), between which data exchange takes place during programme run, the adapter circuit (12, 13) is preferably connected to the data exchange bus (27). <IMAGE>

Description

SPECIFICATION Programmed electronic controller This invention relates to a programmed electronic controller intended in particular for automotive vehicles, which controller serves, for example, for brake slip control and/or traction slip control and contains electronic circuits by means of which control signals, e.g. braking pressure control signals, can be generated in dependence on measured signals under a preset programme stored in a microprocessor or microcomputer with appertaining internal and/or external memories.

Such a programmed electronic controller is already known from the West German published patent application DE-OS 32 34 637.

The controller in question is one for an antilock brake system. By means of this known controller, braking pressure control signals are generated in dependence of sensor signals and/or measured signals which reflect the speeds and the rotational behaviour of the wheels. One embodiment of the controller described in this published patent application contains microcomputers in which the controller programme is fixedly stored. Such microcomputers which consist of a single component and into which the controller programme can be introduced by mask programming are comparatively moderate in price.

It is considered disadvantageous that for practically all types of vehicles a controller programme with special parameters and individual programme steps is required, because, for example, the desired optimal variation of pressure during slip control is influenced by the kind of drive, i.e. front wheel, rear wheel, or four wheel drive, by the design of the brake, and by many other construction features. In addition, different types of special equipment, special reactions to specific disturbances, etc. are desired. The number and the type of existing sensors, such as wheel sensors, must also be taken account of by appropriate programme design. As a consequence, a special microcomputer must be developed for each programme variant, which considerably increases manufacturing and stock keeping costs.

An object of the present invention therefore is to develop a programmed electronic controller which can be adapted in a simple manner and at low cost to the different vehicle types and requirements.

According to the present invention there is provided a programmed electronic controller comprising electronic circuits by means of which control signals can be generated in dependence on measured signals under a preset programme stored in a microprocessor or microcomputer with appertaining internal and/or external memories, characterised in that in the memory or memories a universal programme is stored which can be adapted to different applications and/or designs of the system controlled by the controller and that the controller comprises an adapter circuit which can be modified during manufacture of the control ler and which adapts the programme run to the specific application and/or design.

Therefore, controllers designed for different vehicle types, brake systems, or brake designs can be equipped with one (or several) like, uniformly programmed circuit(s), e.g. single-chip microcomputer(s). Adaptation of the controller to the respective application is achieved by means of a very simple and cheap adapter circuit, which can be modified at minimal cost when the controller is manufactured, for example by boring or interrupting some conducting paths, and thus initiates the programme run desired for the specific vehicle type.

According to an embodiment of the present invention, said adapter circuit contains a bridge circuit or a resistor network by means of which the potential at inputs of the microprocessor, the microcomputer, and/or at the memory inputs can be determined for setting or selection of the desired programme. According to another, particularly advantageous embodiment of the invention, a coder and switch network is provided as adapter circuit which at specific times or at predetermined points in the programme run applies an adapt instruction to the microprocessor, to the microcomputer and/or to the memory inputs. In the remaining time, the processor, computer, and memory inputs are available to receive or pass on other information.

The controller described in the above-mentioned West German published patent application DE-OS 32 34 637 contains two paralleled microcomputers between which a data exchange takes place during programme run in order, inter alia, to check the data flow for consistency and to evaluate such consistency as a criterion for proper functioning. For this kind of circuit -and similar circuits a further embodiment of the present invention is provided, which consists in that the coder and switch network is connected to the data exchange lines and/or to the data exchange bus.

Thus, the data exchange bus existing anyway between the two microprocessors can be used for connection of the adapter circuit. The additional expense required in comparison to conventional controller is therefore restricted to the additional, very simple coder and switch network.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a block diagram showing in a simplified form the most important circuits of a controller as proposed by the invention for an anti-lock brake system, and Figure 2 is a flow diagram of a possibility of integrating the coder and switch network functions according to Figure 1 in the programme.

In the embodiment illustrated in Figure 1, the controller of an anti-lock brake system contains two paralleled microcomputers 1, 2 (MC1, MC2). Via buses 3, 4, signals are fed to the inputs of the two microcomputers 1, 2, which signals are obtained by wheel sensors S, to S4, for example inductive sensors, and evaluated in a trigger circuit 5. The inputs of the two microcomputers 1, 2 are paralleled.

Thus, they both receive the same information, in particular about the rotational behaviour of the individual vehicle wheels.

In the microcomputer 1 all input information is logically combined and processed under a preset programme stored in the microcomputer. Braking pressure control signals are eventually applied to the output A1 of the microcomputer 1; said signals are passed on via the line system 6 to a booster circuit 7 and via the lines 8 to braking pressure control valves 9. By means of these valves, which are usually designed as electromagnetically actuatable multiway valve, the braking pressure in the wheel brakes of the slip-controlled wheels is reduced, maintained at a constant level and in due time increased again, to prevent a locking of the wheels and to achieve as effective as possible a braking operation of the vehicle over a short braking distance while maintaining driving stability.So-called main valves, which in a known manner lead pressure fluid back into the brake circuits and thus replace the pressure fluid volume drained off during pressure decrease, are also included in the valve arrangement 9.

In the illustrated controller circuit, the sensor signals processed in the trigger circuit 5 are processed in the second microcomputer 2 in the same way, in particular under the same programme, as in the microcomputer 1. Via a line system 10 and an adaption step 11, the signals generated by the microcomputer 1 are led back to the input A2 of the second microcomputer 2 after having passed the booster 7. Furthermore, the two microcomputers 1, 2 are connected with each other by a data exchange bus 27. Due to this interconnection external and internal signals of the two microcomputers 1, 2 can be permanently compared. if the signals do not match, this indicates an error, which is why in this case the slip control is switched off through a monitoring circuit (not illustrated) and it is ensured that a normal, i.e. uncontrolled braking operation continues to be possible.

In the embodiment illustrated in Figure 1, an adapter circuit which is essential for the invention, namely a coder and switch circuit 12, 13, is connected to the data exchange bus 27. The coder network 12 here merely consists of a series of paralleled ohmic resistors R1 and/or R2 to R8 which are connected, on the one hand, via a common line 14 to a voltage source +U8, and on the other hand, via a common wire M to the chassis (ground).

Each resistor R1 to R8 is connected via an open switch a, to a8 located inside the switch network 13 with a conductor of the date exchange bus.

For coding of the adapter circuit 12, 13, the prefabricated connection of the resistors Rn to the ground wire M in the coder network 12 is either left as it is or separated. In the present case the resistors R1 to R8 are accommodated on a printed circuit so that separation of the connection to the wire M can be accomplished in a very simple manner by boring open (bores 15, 16, 17, 18) the conductive strip of the connection.

When the switches a, to an of the switch network 13 are closed, therefore, the individual conductors of the data exchange bus 27 are either connected via the coder network 12 to the chassis or via the resistors R1 to R8 to the voltage +UB. In the illustrated example, voltage is applied via the switches a1, a3, a4 and a7, while the switches a2, a5, a6 and a8 are connected to the ground wire M. Via the switch network 13, therefore, an instruction which is fixedly preset by the coding of the coder network 12 can be fed through the data exchange bus 27 to the microcomputers 1, 2.

Since eight switches and connections are provided, there is a total of 256 possible combinations; thus, 256 different instructions can be realised by the coder and switch network 12, 13.

Via the control connections 19 to 20, the switch network 13 is actuated at certain points in time and thus the instruction preset by the coding of the network 12-in the illustrated embodiment in the form of an 8-bit data word-is fed into the data exchange bus 27.

In the controller according to Figure 1, the two microcomputers 1, 2 are connected with each other via the data exchange bus 27 through which, inter alia, signals, which for example represent interim results of the data processing within the microcomputers 1 and 2, are compared for consistency with the corresponding data processed in the other microcomputer.

Figure 2 shows the programme run if the adapter network 12, 13 as shown in Figure 1 is used. Upon application of the control instruction 21 to the switch network 13-see Figure 1-the switches a1 to a8 are closed and thus connected to the coder network 12; this is symbolised by the programme step 22 in Figure 2. In the illustrated embodiment, the instruction determined by the coding of the network 12 is thus fed into the data exchange bus 27 in the form of an 8-bit data word and results - as is illustrated by 24-in a selection of specific parameters, specific programme steps, or other coefficients which influence the programme run of the controller programme stored in the microcomputers 1, 2.The duration of the pressure reduction or pressure build-up pulses in certain control phases, for example, can be determined by means of the instruction coded in the network 12. It is also possible to adapt the controller programme to the changed conditions of front wheel drive, rear wheel drive, or four wheel drive. Influencing of the yawing moment, for example by limiting the maximum pressure differences between the two wheels of an axle by combining the corresponding pressure build-up times or the like, can be "switched on" or prevented by the coding of the network 12 if appropriate programme steps are stored in the microcomputers 1, 2.Adaption of signal processing to the wheel sensors S, to S4 that may be used in each case, in particular to the coordination of the pulse frequency to the angular velocity of the wheels and to numerous other variables depending on the respective type of vehicle and/or brake design is also effected by the coding.

The data selection 24 is followed by the initialisation 25 of the controller programme which now runs in the manner which is appropriate for the respective type of vehicle or design. Adaption of the pulse widths by which the braking pressure build-up and reduction is controlled to the characteristic of the wheel brakes used is also effected by the coding. The triggering of additional functions, for example traction slip control etc., can also be influenced by the coding.

Depending on the embodiment of the controller, the instruction predetermined by the coding of the network 12 is fed to the data exchange bus 27 at large time intervals, for example switching on of the ignition, or at a predetermined point in time within each signal processing cycle. Apart from these input times, i.e. after uncoupling of the coder network 12 by opening the switches in the network 13, the data exchange bus 27 is available unrestrictedly for other functions and/or data transmissions.

By introduction of the adapter network 12, 13 as proposed by the invention, therefore, an important step towards a universally usable controller is taken at very low cost. The fact that the memory requirements may be increased by the universal programme that must be fixedly stored in the microcomputer is of secondary importance, because modern microcomputer chips have sufficient storage space available.

Claims

1. A programmed electronic controller comprising electronic circuits by means of which control signals can be generated in dependence on measured signals under a preset programme stored in a microprocessor or microcomputer with appertaining internal and/or external memories, characterised in that in the memory or memories a universal programme is stored which can be adapted to different applications and/or designs of the system controlled by the controller and that the controller comprises an adapter circuit (12, 13) which can be modified during manufacture of the controller and which adapts the programme run to the specific application and/or design.

2. A controller as claimed in claim 1, characterised in that the adapter circuit (12, 13) comprises a bridge circuit or resistor network (12) by means of which, depending on the application and/or design of the system controlled by the controller, the potential at inputs of the microprocessor, the microcomputer (1, 2) and/or at memory inputs can be determined.

3. A controller as claimed in claim 1, characterised in that the adapter circuit (12, 13) substantially consists of a coder network (12) and a switch network (13) which at specific times or at predetermined points in the programme run applies an adapt instruction to the microprocessor, to the microcomputer (1, 2) and/or to the memory inputs.

4. A controller as claimed in claim 3 with several microprocessors or microcomputers (1, 2) between which a data exchange takes place during programme run, characterised in that the coder and switchnetwork (12, 13) is connected to data exchange lines (27) and/or to a data exchange bus.

5. A programmed electronic controller in particular for automotive vehicles substantially as herein described with reference to and as illustrated in the accompanying drawings.