The body controller is the core component of the automobile to realize the interaction function with the user.
The reliability of its function is directly related to the user’s experience effect and safety factors. In the design and verification stage of the body controller, the reliability of DV experiment must have strict requirements, and the reliability factors need to be analyzed strictly to ensure product quality. With the development of automobile towards integration, more and more functions of interaction with users are replaced by manual control by electrical control.
As the core component of automobile to realize interaction with users, body controller is the key parts of automobile to realize various kinds of body electrical control, such as small lights, low-light lamps used in high frequency, and so on. All kinds of light control, thermostatic element such as steering lights, electric glass elevator control, wiper washing control and so on, are realized through the body controller.
The product quality of the body controller has a key impact on the user’s experience and safety. Therefore, in the stage of product design verification, besides routine functional testing, DV experiment, as a means of verifying hardware reliability, is an important part of product reliability verification.
The following is a description of the factors that may affect the reliability of DV experimental scheme. There are three basic roles that the experimental scheme must have: (1) the experimental object, that is, the body controller; (2) the control detector, that is, the monitoring of the experimental object; (3) the upper computer, that is, the human-computer interaction.
The software that the experimental object requires to run is DV version software, which can meet the needs of the inspector to control its work. The control inspector is the core of the experimental scheme. According to the requirements of the scheme, it can control all kinds of load work of the experimental object, and monitor the working state of the load of the experimental object. The host computer must present the results and states of the experiment to the user, and may even include the setting of monitoring mode. The characteristic of the body controller is that there are many switches and loads, generally there are dozens of them.
For the output of each load and the input of each switch, a hard line is needed between the control detector and the experimental object to satisfy the working control and condition monitoring of the experimental object. The result is a large number of hard wire connections. If so many hard wires are connected manually, the workload in setting up the environment is huge. The key problem is how to ensure the correctness of the connection, as well as how to find out the errors of the connection, which consumes more energy, and the construction of each set of experimental environment needs to be repeated.
This will cause a great deal of experimental process.
Uncertainty factors. Factor: For hard wire connection, we need to make specific custom integrated line speed and connector. When setting up the experimental environment, we can quickly and conveniently realize the hard wire connection between the control inspector and the experimental object, so as to reduce the uncertainty and unreliability of the environment caused by this kind of manual misoperation.
When controlling the switch action, the control inspector needs to consider the acquisition requirement of the actual experimental object for the switch.
Generally, the experimental object needs to be treated with anti-shaking. Therefore, it is necessary to maintain a period of time after the change of the switch control action in order to meet the requirement that the experimental object can correctly recognize the change of the switch action. Switch anti-shake time should be moderate, too short may misstate action and not play a role in anti-shake, too long will affect the user response time, reduce the user experience effect. The shortest time that must be maintained after the change of the switch action of the controller can be set according to the time requirement of the switch of the specific product. For the body controller, the anti-shaking time of tens of milliseconds is generally required. It should not be too short or too long, with the exception of the switch with special requirements. Load detection has been going on since the scheme started to run. Whether the load is in working state or idle state, it is necessary to carry out load state detection. Generally, if inconsistent with the expected state is detected, it should be recognized as an error and reported. When the control inspector changes the working state control of the load, it takes a certain time for the experimental object to receive the control request, to control the load switching working state, and to input the actual working state of the final load to the control inspector, which is called the load switching state time. The time of load switching must be taken into account when the control detector is implemented, otherwise the error will be misreported. The working state of the experimental object can be divided into load switching state and stable state, and stable state can further include stable activation state and stable idle state.
In the stable state, the control detector must periodically check the actual stable state of the test object and compare it with the expected stable state. Mismatch indicates that there is an error, and the error needs to be recorded and reported. For the control of the detector’s monitoring cycle, it should not be too long, otherwise there will be no problem of detection errors; the shorter the monitoring cycle, the more accurate and reliable the experimental results. In the process of experiment, it is appropriate to determine that the value should not exceed 100 milliseconds, which is usually set to tens of milliseconds. The upper computer is the part of human-computer interaction, including the interactive interface. The functions that must be provided include the display of the monitoring results of the wrong load working state and the control of the working mode. The working mode control is sent directly to the control inspector, and the feedback of the load working state is received. Some schemes combine the roles of host computer and control detector. Because the control detector must satisfy the above requirements, so the time requirement is more sensitive, it must have a special MCU to control the realization of this function, from the perspective of time sense, it is not suitable for the upper computer to achieve. In the design of DV experimental scheme of body controller, the role and function allocation of the whole scheme, the customization requirement of line speed, the time sensitivity requirement of host computer, the anti-shake requirement and the detection cycle requirement in the process of load detection all have important guiding significance for the accuracy and reliability of the experimental results.