Body and Chassis Controls

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Contents

Overview

New Eagle engineers offer system engineering and custom embedded control systems solutions including system designs, development, and integration tools and processes. Services that are provided by New Eagle include controls, production software testing, component and hardware selection and development, user interface devices, and long term customer support.

A picture of a vehicle showing the chassis dynamics variables using the SAE coordinate system.
Chassis Dynamics Variables Using SAE Coordinates

We have experience with all major chassis control systems including:

  • Braking Systems
    • ABS
    • TCS
    • ESC
  • Steering Systems
    • Electronic Power Steering
    • Active Rear Steering
    • Active Front Steering
  • Suspension
    • Bi-State Damping Control
    • Contunuously Variable Damping Control
    • Roll Control
  • Vehicle Dynamics Sensing
    • Angular Rate Sensing (Yaw/Pitch/Roll)
    • Accelerometers (Lateral/Longitudinal/Heave)
    • Steering Sensors
    • Wheel Speed Sesning
    • Vehicle State Estimation
    • Vehicle State Diagnostics with Sensor Reasonableness Checks

Control System Solutions

Brakes

Anti-Lock Braking System (ABS)

New Eagle has experience developing Antilock Braking Systems. Our engineering team can integrate ABS with regenerative braking on electric and hybrid electric vehicles.

Traction Control System (TCS)

New Eagle has experience developing Traction Control Systems. Our engineering team can integrate TCS with the supervisory control unit on electric and hybrid electric vehicles.

Electronic Stability Control (ESC)

New Eagle has experience developing Electronic Stability Control Systems. Personnel at New Eagle hold patents for ESC and have developed actuators, controllers, and sensors for these systems. We have integrated the system into vehicles and have developed robust fault handling from input and output diagnostics to vehicle performance sense checks. We have also integrated braking ESC with other vehicle control systems such as controlled steering, roll control and electronically controlled suspension systems to ensure that the systems work together cohesively.

An ESC system is an example of providing control through a secondary system. The ESC system controls yaw rate and side slip through differential braking. The primary system for controlling yaw rate and side slip is the vehicle steering system.

Electric Park Brake (EPB)

A high level Matlab/Motohawk diagram of an electric park brake system.
High Level Matlab / MotoHawk Diagram of An Electric Park Brake Control System.

New Eagle has experience developing Electric Park Brake vehicle subsystems. Our engineering team can design a control system and write software to integrate a park brake mechanism into a vehicle. Software development includes integration with the vehicle information bus, mode logic with fail-safe, and actuator sensing and control.

In addition to the electric park brake trigger switch a variety of vehicle conditions may affect desired electric park brake behavior. Integration with the vehicle’s network allows for these features. Consider the following example cases and notice the subsystems in the Electric Park Brake example for ‘Releasability’, ‘Intelligent Brake Apply and Reclamp,’ and ‘Mode Logic’:

  • Inhibit park brake release without service brake depression
  • Inhibit park brake release during vehicle charging
  • Modulate apply level based on road grade
  • Automatic reapply of park brake based on vehicle speed
  • Automatic apply of park brake based on charger presence
  • Change apply mode based on vehicle speed

For production intent systems, sensors represent additional and sometimes unrealistic cost. New Eagle has experience estimating park brake state based on available measurements. Model based state estimation methods are used to track the park brake actuator state of relevance in order to provide state feedback to the controller. This allows for closed loop control methods which can be tuned to optimize desired functional characteristics such as response time, or energy consumption. In the park brake example a linear state space observer is used to estimate relevant states; New Eagle also may use other model based approaches for state estimation as appropriate.

Suspensions

Electronically Controlled Damping

New Eagle has experience developing Electronically Controlled Suspension Systems including bi-state damping, continuously variable damping and load leveling systems. Engineers at New Eagle hold patents for suspension control systems.

Roll Control Systems

New Eagle personnel have experience developing roll control either through direct actuation of controllable roll bars or indirectly though controlled suspension systems.

Steering

Electric Power Steering (EPS)

New Eagle personnel have developed and hold patents on electric power steering systems. Electric power steering systems require tight integration of the controls and diagnostics due to the fast reaction time of vehicles to steering inputs. While a typical ESC or ABS system has up to 1 second to diagnose faulty sensor signals, an electric power steering system must sense some faults within tens of milliseconds and provide immediate fault handling.

Integration of Multiple Chassis Control Systems

Vehicle dynamics control using a master control system with an arbitrator.
Vehicle Dynamics Control Using Master Control System with Arbitrator
Integration of chassis subsystems requires not only the development of the individual systems, but also the integration step. If proper integration is not achieved, then systems can fight each other, which can cause unwanted results such as vehicle oscillations. A vehicle dynamics supervisor is required in order to define the vehicle state and control the overall actuation. For example, an electronic stability control (ESC) system integrated with a rear steer system or and active front steering system can help to reduce the workload on the ESC system and thus reduce power loss and brake wear.

Engineers at New Eagle have experience integrating multiple chassis control systems such as:

  • Closed Loop Rear Steering Integration with ESC
  • Normal Force Estimation From Suspension for ABS Rough Road Enhancement
  • Normal Force Control through Roll Control to Enhance ESC
  • Normal Force Control through Real Time Damping Control to Enhance ESC










OEM Instrument Cluster Control

New Eagle offers solutions to control any stock OEM instrument cluster that is CAN-controlled. This includes any J1939, regular and extended IDs, 2 wire GMLAN, and any bus speed (50-1000kbaud). New Eagle can either reverse engineer all of the cluster functionality or build the control off of a predefined database. The approach requires the use of a gateway controller that intercepts, filters, and redirects all the signals between the OEM body, engine, and instrument cluster controllers and modifies them based on the desired gauge commands.


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