DE102017221429A1 - Means of transport, work machine and bus participant for a PSI-5 bus - Google Patents

Abstract

It proposes a means of transportation, a working machine and a bus participant for a PSI-5 bus. The bus user comprises: a microcontroller and a sensor, with software installed on the microcontroller, by means of which it is set up to operate the sensor as a slave in the PSI-5 bus.

Description

The present invention relates to a vehicle, a work machine and a bus subscriber for a PSI-5 bus. In particular, the present invention relates to a flexible and inexpensive hardware for implementing PSI-5 bus slaves.

Modern means of locomotion are increasingly provided with environmental sensors and actuators to assist the driver in cooperation with evaluation in the management of the means of transport. The same applies to work machines and their users. The peripheral sensor interface 5 ("Peripheral sensor interface 5", PSI 5 ) is a bus system, which guarantees high interference immunity by its design. It is current and voltage controlled and uses Manchester coding as well as CRC (cyclic redundancy check). Since this is an open standard, an implementation without license costs is possible, which means that the PSI 5 Standard has spread rapidly. Further distribution is foreseeable. In the PSI 5 is a master-slave system, ie, there is always a higher-level control unit (master), which interrogates the slave control units (slaves), controls and synchronizes the communication. The digital transmission of information offers important advantages compared to analog transmission systems used today, such as interference immunity and diagnostic capability. PSI is used 5 Currently in the automotive sector, especially for sensors (eg airbag control units), but is increasingly used in sensor new developments.

PSI-5 slave interfaces are not available on the market. Therefore, there is no way to adapt a PSI-5 for sensors without a significant (hardware) -developungsaufwand to operate. Rather, a large manufacturer must always be involved, who develops and implements the required software.

Based on the aforementioned prior art, it is an object of the present invention to realize the realization of PSI-5 bus systems more flexible and cost-effective.

The above object is achieved by a bus subscriber for a PSI-5 bus, which includes a microcontroller and a sensor. The microcontroller can be understood as a conventional microcontroller on which a software can be installed without the need for an FPGA or ASIC permanent and / or complex programming must be made. In particular, the microcontroller can be recorded by the software by means of a simple control unit (for example a PC, a tablet or another automobile control unit). By software is meant, for example, the operating system of the microcontroller. In other words, the software is used to operate the bus subscriber according to the invention as such on the PSI-5 bus. The sensor may, for example, an environment sensor, an electromechanical sensor, an optical sensor, or the like. his. His information is also distributed via a PSI-5 bus. According to the invention, the software is set up to operate the sensor as a slave in the PSI-5. The role of the slave excludes, in particular, that the bus user polls and / or controls the remaining slaves and / or synchronizes the communication with them. By using the microcontroller and the software installed on it, a flexible adaptation of the functionality of bus subscribers according to the invention can be achieved. In addition, the component costs can be significantly reduced. Functional enhancements can be made by simple software updates without having to swap hardware. In particular, the software (for example by means of another bus subscriber and / or without further processor) can be updated over-the-air or provided with new software. Even after delivery to a customer, a means of transport provided with a bus subscriber according to the invention or a corresponding work machine can be flexibly changed in its functional scope, in particular increased.

The dependent claims show preferred developments of the invention.

The microcontroller is preferably configured to respond to requests received from a master of the PSI-5 bus. In other words, the microcontroller is set up to operate a communication of the PSI5 master. In particular, the microcontroller is set up to answer only the requests received from the master of the PSI-5 bus. These operations may be initiated, for example, by a predefined voltage signal from the PSI-5 bus sent by the master. In this case, the microcontroller can, for example, activate the sensor, query data or adjust operating parameters of the sensor. In particular, the microcontroller can also take over further functions of the bus subscriber according to the invention, such as, for example, the evaluation of the data supplied by the sensor and / or the initiation of suitable measures. In this way, the microcontroller can be used for a variety of tasks, thereby making the hardware cost for the microcontroller economical by providing a variety of functions.

The bus subscriber according to the invention can be installed in production vehicles which are located in the field, in particular after delivery to the respective customer, where they are operated in the intended manner. In other words, the inventive structure of the bus subscriber is not understood as a prototype.

The sensor may, for example, a level sensor, an acceleration sensor (eg for the airbag and / or the chassis of a means of locomotion), an electromagnetic sensor, a magnetostrictive sensor, an optical sensor, a pressure sensor, a vacuum sensor, a rotation rate sensor and / or a position sensor (eg rotary, linear). The above examples are not exhaustive and are for illustrative purposes only.

The bus subscriber according to the invention can also have, for example, a servomotor. In other words, the bus user can have an actuator, wherein the microcontroller is in particular further configured to operate the servomotor as a slave in the PSI-5 bus. The abovementioned embodiments therefore also apply correspondingly to the actuator / servomotor and its relationship to the microcontroller / bus user.

The software for the microcontroller can be written (originally) in the programming language "C", for example. In other words, the functionality is based on a source code written in the "C" programming language. Due to the widespread use of the programming language "C" worldwide use and update of the functional scope of the bus subscriber according to the invention is ensured.

It is a core idea of the present invention to implement the PSI-5 protocol in software on smaller microcontrollers. This provides a proprietary protocol implementation that is initially independent of an IP or vendor that implements it in an ASIC or FPGA. Such a realization allows for the implementation of sensor systems very high degrees of freedom in terms of hardware selection and allows in comparison to ASICs or FPGAs cost-effective implementation, even in small quantities. Another advantage of implementing it on a microcontroller is the fact that the controller, in addition to protocol processing, also has other specific tasks, such as e.g. Calculation and conversion of values, implementation of analog inputs, diagnostics and the like can take over. As a further advantage here is the simultaneous use of further bus systems, such as e.g. CAN, on the same controller, to call.

Another advantage of using the "C" programming language allows for the greatest possible independence from the microcontroller model used or enables easy porting to other derivatives and systems. The hardware-specific differences of the available controller derivatives with regard to the necessary controller peripherals, such as timers, interrupt, etc., can be handled either via compiler switches or via different libraries. Due to the free availability of compilers such as GNU C, the OpenSource or OpenHardware idea, can be followed up as needed, as GNU C is available for a variety of microcontrollers in the market.

Certain requirements regarding the timer and interrupt functions are made to the microcontroller in order to be able to resolve the temporal dependencies of the protocol. The detection of the Sync and information pulses of the protocol via these functions. An interrupt function is used to detect the PSI-5 sync pulse that marks the beginning of the data transfer. The subsequent pulses, which contain the data to be transmitted, are evaluated via one or more timers. These requirements are met by most of the microcontrollers available today.

According to a second aspect of the present invention, there is proposed a traveling means comprising a PSI-5 bus, a PSI bus master, and a bus subscriber according to the first aspect of the invention. The sensor is in this case in particular a sensor provided for the operation of the means of locomotion. In particular, the sensor can be permanently provided for remaining and operating in the means of locomotion. The sensor may be, for example, a vehicle dynamics sensor, an environmental sensor, etc. The software running on the bus subscriber according to the invention can be updated, for example, via an over-the-air interface of the means of locomotion in order to enable bugfixing and / or functional enhancements.

According to a third aspect of the present invention there is provided a work machine comprising a PSI-5 bus, a PSI-5 bus master, and a bus subscriber according to the first aspect of the invention. The sensor may be, for example, a sensor provided for the operation of the work machine. In particular, the sensor is provided for the permanent whereabouts and operation in the work machine. It can be designed, for example, as an optical sensor, force sensor, distance sensor, environmental sensor, or the like.

In this way, the means of transport according to the invention and the working machine according to the invention realize the features, combinations of features and the advantages of the bus subscriber according to the invention that can be seen in a corresponding manner so that reference is made to the above statements to avoid repetition.

• 1 eine Prinzipskizze zum Aufbau eines erfindungsgemäßen PSI-5-Systems, und
• 2 eine schematische Darstellung eines Ausführungsbeispiels einer Bus-Anbindung eines erfindungsgemäßen Bus-Teilnehmers.

Further details, features and advantages of the invention will become apparent from the following description and the figures. Show it:

• 1 a schematic diagram for the construction of a PSI invention 5 -Systems, and
• 2 a schematic representation of an embodiment of a bus connection of a bus subscriber according to the invention.

1 shows a designed according to the invention bus system, in which a designed according to the prior art master control unit 6 with a microcontroller 3 and one over an interface 7 to the microcontroller 3 connected transceiver ASIC 8th is set up to coordinate the bus communication of a PSI-5 bus 2. The PSI-5 bus 2 is designed as a two-wire system in which individual bus participants 1 comprising individual sensors 4a . 4b or bus subscribers connected in series 1 comprising sensors 4c . 4d . 4e . 4f . 4g be operated and linked information technology. While the sensor 4a is designed as a conventional sensor, the sensor 4b according to the invention via a microcontroller 3 integrated as slave in the bus system. Also the sensors 4c and 4d are in accordance with the invention via microcontroller 3 integrated into the PSI-5 bus 2 as slaves. The sensors 4e . 4f are configured in a conventional manner while the bus subscriber 1 comprising the sensor 4g in accordance with the invention via a microcontroller 3 into the PSI-5 bus 2 is integrated.

2 shows a schematic diagram of the electrical network for integrating a sensor designed according to the invention 4 with a microcontroller 3 , Since PSI 5 in a transmission direction is current and microcontroller usually have no power interfaces, they must be implemented externally. In this case, commercially available circuits for constant current sources can be used. An adaptation to higher voltage levels, as they use microcontroller, such as the usual 12V power battery systems, must also be implemented externally via appropriate voltage divider. Simple resistive voltage dividers are generally sufficient for this purpose. Increasingly available PSI-5 transceivers on the market can do the same. The microcontroller 3 is set up, a switch 9 by means of which a constant current source for driving a predefined current I _sink between the wires of the PSI-5 bus 2 is initiated. The constant current source is connected in parallel with a capacitor Cs, above which the bus voltage V _SS (Control signal from the master bus user, not shown) drops. The resistors R _CS denote the contact resistance of the sensor connector. As a result, a flexible, cost-effective and largely manufacturer-independent bus topology is possible. In addition, sensors and actuators, in particular, can be easily and inexpensively integrated in PSI 5 Bus systems are integrated.

LIST OF REFERENCE NUMBERS

1

Bus devices

2

PSI-5 bus

3

microcontroller

4, 4a-4g

sensors

6

control unit

7

interface

8th

Transceiver ASIC

9

counter

C _S

capacitor

I _sink

predefined current

R _CS

Contact resistance of the sensor connector

V _SS

Bus voltage

Claims (10)

Bus subscriber (1) for a PSI-5 bus (2), wherein the bus subscriber (1) comprises: • a microcontroller (3) and • a sensor (4), wherein on the microcontroller (3) software is installed, by means of which it is arranged to operate the sensor (4) as a slave in the PSI-5 bus (2). Bus participants after Claim 1 wherein the microcontroller (3) is arranged to control communication of the bus user (1) from the PSI-5 bus (2). Bus participants after one of the Claims 1 or 2 wherein the microcontroller (3) is adapted to receive new software via an over-the-air update. Bus subscriber according to one of the preceding claims, wherein the microcontroller (3) comprises no FPGA and no ASIC. Bus subscriber according to one of the preceding claims, wherein the sensor (4) - a level sensor and / or - an acceleration sensor and / or - an electromagnetic sensor and / or - a magnetostrictive sensor and / or - an optical sensor and / or - a pressure sensor and / or - a vacuum sensor and / or - a rotation rate sensor and / or - Includes a position sensor. Bus subscriber according to one of the preceding claims further comprising a servomotor, wherein the microcontroller (3) is further adapted to operate the servomotor as a slave in the PSI-5 bus (2). Bus subscriber according to one of the preceding claims, wherein the software is written in the C programming language. Means of transport comprising a PSI-5 bus (2), - a PSI-5 bus master (6) and - A bus subscriber (1) according to any one of the preceding claims, wherein the sensor (4) of the bus subscriber (1) is a sensor (4) for the operation of the means of locomotion. Means of transportation Claim 8 , which is set up to receive new software for the microcontroller (3) via an over-the-air update. Working machine comprising - a PSI-5 bus (2), - a PSI-5 bus master (6) and - a bus participant (2) according to one of the preceding Claims 1 to 7 , wherein the sensor (4) of the bus subscriber (1) is a sensor (4) for the operation of the working machine.

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