Real Time Simulator (RTS) for Brake Management System (BMS) of an Aircraft consists of different models of sub system/components of Brake Management system. These models run and interact with each other to simulate braking behavior of aircraft in real time. BMS Controller embedded with control law, is interfaced with RTS. BMS control law is tested and evaluated using RTS before testing evaluating BMS on Aircraft through taxi and flight trials.

1. Introduction

Brake Management System of the Aircraft is safety critical system. The BMS control law which incorporates PID control to provide antiskid protection. BMS is evaluated on aircraft through taxi and flight trials costs a lot of time and money. The Real Time Simulator which simulates aircraft dynamics and BMS sub-system/components has helped in understanding system behavior, in improving control law and minimizing number of test on the aircraft.

2. Real Time Simulator

The real time simulation of Brake management system is used to evaluate and optimize BMS control law before integrating & evaluating on Aircraft.

The test facility has the following features.

i. Real Time Simulation of BMS sub-sytem/component (Wheel Speed Transducer, Brake Manifold, Brake Demand, Brake Pressure, tyre, wheel and brake and aircraft dynamics),

ii. Real time data acquisition signals,

iii. Offline analysis of the recoded data.
iv. Configurable patch panel to select real signals or simulated signal. v. Facility for generation of system failures (partial or total) temporary or permanent.

2.1 Hardware

The hardware consists of NI real-time PXI system to achieve above mentioned features. The PXI system comprises Real Time Controller NI PXI 8110, NI PXI 1045 Chassis, high accuracy analog and discrete input/output cards and failure injection modules. The frequency signals are simulated by high speed (lMSample/sec) analog output card(PXI 6733)

2.2 Models simulation

BMS Sub-systems models are simulated by Simulink models. The Simulation Interface Toolkit (SIT) is used to run Simulink models on a real-time target. All I/O signals are acquired during testing and logged to file for offline analysis.

2.3 Model execution

The critical part of the real-time simulator is executing BMS sub system models in real time. The models are executed in 300 micro seconds to make simulation as real as possible. This microsecond simulation enables high fidelity simulation.

2.4 Patch Panel

The patch panel provides the following facility

i. Feasibility of selecting signals partially from rig and partially from simulated system,

ii. Permanent connectivity of all acquired signals to Data acquisition system for logging
data.
iii. Monitoring signals externally without breaking any continuity,

iv. Injection of external signals instead of rig/simulated signals after disconnecting the rig/simulated signal.

2.5 Model Validation

The BMS Models are validated through different phases as given below: i. Each model is given a known input and checked for known output, ii. Models are validated by giving a historical data (dynamometer data/ Ac data) and output is compared with historical data, iii. Physical BMS components will be replaced one by one by simulated model and output is compared with output of physical components iv. Lastly, the entire BMS components are replaced by simulated models and outputs are compared.

CLAIMS:

What is claimed is:

1. A Real Time Simulator for Brake Management System (BMS) which simulates BMS components and aircraft environment to BMS controller to evaluate control law comprises:

High fidelity models running in real time Real time data acquisition of all signals Configuration patch panel Failure simulation Historical test data as input

2. The invention of claim 1 further comprising a PXI Real Time Controller NI PXI 8110, PXI 1045 Chassis, high accuracy analog, discrete and frequency input/output cards.

3. The invention of claim 2 where in the high fidelity BMS sub-system/components models are running in real time and interacting and exchanging data among models.

4. The invention of claim 3 where in the high fidelity models are executed in 300 micro seconds to make simulation as real as possible. This microsecond simulation enables high fidelity simulation.

5. The invention of claim 4 where in model modified parameters are fed back to the controller and controller output are fed as model inputs.

6. The invention of claim 1 has configuration patch panel to select real signals or simulated signal as per the test scenario.

7. The invention of claim 1 has facility to simulate system failures (partial or total) temporary or permanent to test robustness of the control algorithm of BMS control law and its failsafe operation.

8. The invention of claim 1 has facility to input Historical test data (aircraft /Dynamometer data) and compare output with Historical output data.

9. The invention of claim 1 is used to evaluate and optimize BMS control law before integrating & evaluating on Aircraft and hence minimizing number of software build on aircraft and number of test points on aircraft enabling fast BMS control law clearance & certification.