Case Studies

NASA Robonaut 2

NASA Battery Simulation System

Posted in Aerospace, Battery Pack Test Systems, Green Technology, LabVIEW, Test & Measurement Automation, Test and Measurement, Test Stand

Summary

DMC leveraged our established Battery Management System (BMS) Testing Platform to deliver an automated Battery Simulator System to a NASA research group. NASA needed this system to facilitate development of highly specialized battery devices. These battery systems were designed to provide mobile power for advanced electromechanical systems such as Robonaut 2, a dexterous humanoid robot created to perform a wide range of tasks to assist astronauts on the International Space Station.

The Battery Simulator System delivered by DMC provides the ability to test BMS devices using a Hardware In the Loop (HIL) testing approach. This HIL testing is performed before those devices are fully incorporated into the large battery packs they are designed to monitor and manage. The system provides software-controlled simulated signals for all input sensors connected to the BMS, and provides the ability measure relevant outputs and responses from the BMS. This makes it possible to perform fully automated testing and validation of BMS functionality across any realistic range of input conditions the device may encounter in field operation.

NASA Battery Simulator System

NASA Battery Simulator System

NASA Relay Multiplexer Manual Control

NASA Cell Simulator Controller

NASA Temperature Sensor Manual Control

NASA Temperature Sensor Simulator

NASA DMM Soft Front Panel

NASA DMM Soft Front Panel

Solution

DMC analyzed and assessed NASA's requirements and goals for their BMS testing application, and designed a customized Battery Simulator System to directly satisfy these needs. The resultant system is capable of providing a total of 108 simulated cell voltage channels and 50 simulated resistive temperature sensor channels. All of these channels are software controllable and dynamically adjustable across the realistic operating ranges for these BMS input signals.  
 
Extensive details on the design and capabilities of this Battery Simulator System are available within this Battery Simulator System White Paper.

Programmable and Open Source
NASA wished to have available in-house LabVIEW developers program the specific test processes to be used to validate their BMS designs. To accommodate this, DMC delivered a complete set of open source driver libraries for all Battery Simulator System hardware modules so that developers on NASA's team could perform effective high level programming of the desired testing procedures.  
 
Manual Mode Operation
To supplement these driver libraries and allow basic system operation while NASA's developers programmed a top level test application, DMC also delivered a complete Manual Mode application. This software package provided the NASA team with full on-demand manual control of Battery Simulator System functionalities through a variety of UI screens, while providing detailed feedback on system activities through comprehensive system status displays/diagrams.
 
Automatic System Self-Checks
The BMS Test System software also included a variety of automated “self-test” diagnostic routines. These self-diagnostic functions are available to run from within the Manual Mode application described previously. 
The design of the Cell Voltage and Current Measurement Module is such that it serves not only as a powerful measurement tool for evaluating BMS performance, but also as a powerful tool for evaluating its own performance and the performance of other test stand sub-modules like the Cell Simulator and Temperature Sensor Simulator modules. Thus, by leveraging the Battery Simulator System's inherent connection multiplexing and high accuracy DMM measurement capabilities, these diagnostic routines make it possible to evaluate/verify the basic functionality and performance of the primary test system sub-modules. These diagnostic routines include the ability to perform a DMM based pseudo-calibration of the Pickering Cell Simulator modules by storing a calibration offset to apply to each voltage output set point based on DMM based feedback on the expected versus actual output voltage.

Learn more about DMC's battery pack and BMS services.

Customer Benefits

  • Turn Key System: DMC built upon numerous established hardware and software subsystems, while combining and configuring these building blocks into a complete system customized to the customers unique requirements and design preferences
  • Open Source: NASA wished to use in-house LabVIEW developers to program specific test processes, so DMC delivered complete open source driver libraries to allow high level programming and control of all system hardware functions
  • Precision: 0.1% precision on simulated temperatures sensors, +/- 2 mv precision on simulated cell voltages, and 7 1/2 digit voltage/current/resistance measurements provided by NI PXI 4071 Digital Multimeter
  • High Channel Count: 108 cell battery stack simulation and 50x 4-bit resistive temperature sensor simulation

Technologies