Developing an Energy Conservation and Safety System for a Heavy-Duty Vehicle

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"We used NI tools to integrate key technologies and enhance development efficiency with modular software and hardware, which helped our team finish this project and pass tests in just six months."

- 何建男 - Chien-Nan Ho, 鷹翔科技有限公司

The Challenge:
Developing tools for analog analysis, hardware implementation, test and verification, and effective integration with other measuring modules for an energy-efficient safety system for special vehicles, which involves energy-efficient system control, safety system design, and the integration of onboard information and communication.

The Solution:
Using the NI sbRIO-9636 module and NI LabVIEW system design software as the basis of an energy-efficient safety system.

Author(s):
何建男 - Chien-Nan Ho - 鷹翔科技有限公司
蔡宗翰 - Tsung-Han Tsai - 鷹翔科技有限公司
張國樑 - Kuo-Liang Chang - 鷹翔科技有限公司
蔡則彬 - Tse-Pin Tsai - 鷹翔科技有限公司
蔡佳男 - Chia-Nan Tsai - 大東車體股份有限公司
蔡佳豪 - Chia-Hao Tsai - 大東車體股份有限公司

The Environmental Protection Administration, Executive Yuan, R.O.C. launched an evaluation and testing plan for garbage truck adaption using energy-efficient technology to implement a national policy advocating energy saving and carbon reduction. For this project, Ying Xiang Technology and Dar Don Vehicles Co., Ltd. worked together to develop the first plug-in, hybrid-electric hydraulic system in Taiwan. This system consisted of four major subsystems: the battery management system, the electric motor control system, the hydraulic system, and the energy recycling system. The battery management system and the electric motor control system replaced the power take-off (PTO) technology that conventional garbage trucks use to connect with the engine or the gearbox to drive the hydraulic system. The energy recycling system could recharge the battery while the vehicle was running, thus realizing the hybrid feature.

System Design: Simulation and Verification

We adopted the V-model for our system design. First, we clearly discussed the system specification requirements then modeled each subsystem and connected them to each other using simulation software. We used a hardware-in-the-loop (HIL) test system with the developed control software. During the testing process, whenever we needed a modification, the team turned back to adjust the model parameter or control logic. When we achieved system optimization, we loaded an MCU onto a real vehicle system for testing and verification to verify if it met the initial system specifications. Therefore, we put the advanced graphical programming and development environment offered by LabVIEW and the multiple high-integrity hardware devices together. Under the NI PXI environment, we put the system model developed with LabVIEW and the control logic developed with the NI sbRIO-9636 module into the HIL verification system. Lastly, we put the system through final system testing and verification with real systems and vehicles. By doing this, we reduced the cost and time needed for development and testing.

Figure 1. Energy-Efficient System Analog HIL Architecture

The conventional garbage truck using a sealed compression compartment is powered by an engine and gearbox connected with the PTO to drive the hydraulic system’s compression movement. But the compression system’s operation increases the engine’s revolutions, producing loud noises and a large amount of exhaust fumes. We developed the plug-in, hybrid-electric hydraulic system to replace the conventional sealed compression compartment. In the energy-efficient control system, we use lithium batteries and an electric motor to provide the power needed by the hydraulic system, and we can shut down the original PTO system during electric mode. Also, the energy recycling system can recycle the energy produced by brakes in the form of hydraulic pressure, which would have otherwise been wasted. This recharges the batteries and helps provide the power needed during vehicle startup. The plug-in, hybrid-electric hydraulic system keeps the original PTO architecture for two reasons. First, if the system is short on electrical power and cannot operate, the PTO architecture can perform compression. Second, if the PTO can drive the motor to revolve in reverse, it can turn the motor into a generator to recharge the batteries, and create the hybrid feature.

Figure 2. Motor and Battery System

Figure 3. The NI sbRIO-9636 MCU and OBU System

The safety system includes an obstacle detection system and a redundancy system design. First, during the garbage truck’s compression operation, trash under pressure can often be ejected and potentially cause injuries among civilians or cleaning staff. Therefore, we use a laser scanner and imaging system to determine if there is a human in the predefined area by detecting the distance and relative position from the main vehicle to the person or object behind it, and then sending the related information to the central control MCU. Based on this information, the system can determine the relative position of the person and object during and after vehicle operation and can issue an alarm or emergency stop notice to ensure personal safety.

We loaded the on-board unit (OBU) into the vehicle to collect data used during real operation of the plug-in, hybrid-electric hydraulic system. After integrating the controller area network (CAN) inside the vehicle with the CAN of the electric compression compartment, the communication modules can transfer data back to the collection system via GPRS or a wireless 3.5 G network, and the data can be stored in the database. The data analysis system can analyze the stored operation data. Based on the compression compartment’s total voltage, total currency, average battery temperature, SOC, and other data items, we can understand battery usage characteristics, including power consumption and the battery’s estimated lifetime, during the electric compression compartment’s operation. We can also evaluate temperature fluctuation during operation and the estimated duration of the battery based on compression times. Leakage detection and emergency halt can help us understand whether the electric compression compartment had a failure and enable real-time monitoring and analysis to improve system performance.

Why We Chose NI Technology

We used the latest products from NI, including the NI sbRIO-9636 module, to rapidly develop the ECU controller and set up the test and verification bench for a special vehicle safety system. This single PCB integrates real-time processors and programmable digital I/O, analog I/O, and an embedded CAN bus interface. The system meets the needs of this project. We can easily install it in vehicles and quickly integrate it with other systems because of its small size. We can also use a LabVIEW human machine interface (HMI) for data observation and analysis during system operation, which largely reduces the time and effort needed for system integration.

We used NI tools to integrate key technologies and enhance development efficiency with modular software and hardware, which helped our team finish this project and pass tests in just six months. Currently, this garbage truck is in service with Xizhi Trash Cleaning Team of Xinbei City, giving citizens the experience of a new generation, energy-efficient garbage truck. Thanks to NI virtual control products featuring fast integration and easy-to-learn, flexible, scalable, and diverse products, we quickly solved all the technical problems we encountered during this project.

Figure 4. Real-World Operation of the Energy-Efficient Safety System

Author Information:
何建男 - Chien-Nan Ho
鷹翔科技有限公司
Taiwan
Tel: (03)471-2201 ext. 329578
chiennan.ho@gmail.com

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