MeritorWabco introduces collision safety system with active braking

MeritorWabco Vehicle Control Systems has introduced OnGuard, a forward-looking, radar-based adaptive cruise control system with active braking for commercial vehicles.

New to the North American industry, the system improves vehicle safety by automatically using the vehicle's foundation brakes to decelerate the vehicle when a pre-set vehicle following distance is compromised.

“OnGuard was designed to equip drivers with automated features that help ensure safe following distances and provide active braking as needed,” says Jon Morrison, president and general manager, MeritorWabco Vehicle Control Systems. “The driver is still the critically most important element in maintaining vehicle safety. However, the system can provide the additional split-second deceleration needed to maintain control of the vehicle in an emergency situation.”

Automatic foundation brake intervention distinguishes OnGuard from existing passive collision warning systems. These alert the driver to a potentially dangerous situation through alarms.

With OnGuard, if the pre-determined “safe” distance is compromised, the system will provide visual and audible warnings to the driver through an in-cab display, then automatically intervene with foundation braking and throttle controls until the driver can respond with the appropriate corrective action.

“The driver is responsible for stopping the vehicle,” Morrison points out. “OnGuard is not intended to stop the vehicle without driver intervention.”

Foundation brake deceleration can be as great as one-third of a full brake application for the vehicle, but within safe limits for the driver to take control.

OnGuard is active when the vehicle is traveling above 19 mph. It is inactive at lower speeds to eliminate nuisance alarms in non-threatening driving situations, for example, when creeping up to a traffic light.

OnGuard uses very little hardware, just the radar sensor and in-dash display, and fully integrates with MeritorWabco's anti-lock braking and stability control systems. An extension of the company's anti-lock braking system (ABS) electronic control unit (ECU), the system uses software to coordinate object detection, braking, and throttle adjustment.

“This allows the customer to build a pyramid of safety for the vehicle with stability control and collision safety system, versus having additional ‘add-on’ systems,” notes Morrison.

“OnGuard's sequence of monitoring, warning, and intervention is an important part of MeritorWabco's strategy to reduce false alarms,” he says. “The system uses a proprietary time-to-collision algorithm, unlike the simple two-second headway alarms used by today's passive braking systems.”

Being an advanced system, OnGuard can reliably filter out radar clutter from highway dividers, cars in adjacent lanes, or the path of the road — a curve, dip, or hill, explains Morrison. However, it is sensitive enough to detect motorcycles and pedestrians in the lane of travel.

OnGuard is targeted for third quarter 2008 availability as a factory-installed option at several truck brands.

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