Active Shock Management (ASM)

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Shock Control Unit and Valve

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4 wheel system

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Shock Control Unit (SCU)

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Damping Valve

Active Shock Management (ASM) is a unique control system consisting of electronic controls, a damping valve and patented ride control software algorithms which enables shock absorber manufactures to offer semi active damping products to their customer. Our hardware is easily adapted to existing shock absorbers and when coupled with our electronics and software represents a complete system that speeds time to market.

System Components

Software The basis of our system is the Active Shock Ride State Aware™ algorithm which is firmly rooted in years of real world vehicle dynamics experience. It has taken all of the adjustments and tuning methods used in off-road, rally and pavement racing shock absorbers and boiled them down into the physics that govern the behavior of a vehicle when it is driven at the limit.

Unlike adjustments with passive dampers, the algorithm selects the best setting in real time so it is continuously optimizing the damping throughout a corner or bump, not just adjusting for a particular road surface like some adaptive technologies. It is fully self-tuning and does not require interaction from the driver, the algorithm acts like an on-board vehicle dynamics engineer making adjustments 1000 times a second.

The Ride State Aware™ algorithm reads analyses the suspension at millisecond time increments then selects the most appropriate strategy for controlling the damping from a range of pre-defined scenarios.

Damping Valve is fitted to the damper and acts like a variable orifice pressure relief valve. Flow to the valve is controlled by a series of check valves in the damper that allows a single valve to control both compression and rebound damping.

The Shock Control Unit (SCU) is mounted to the sprung mass adjacent to the top shock mount. It monitors the integrated sensors and calculates the optimal damping, then outputs a control signal to the continuously variable damper valve.  This results in a damper force in parallel with the spring force that can be used to remove the energy from the spring or from the suspended mass. Both 12V and 24V valves and SCUs are available to fit most vehicle power.

Master Controller can be mounted anywhere on the vehicle. The master controller is networked with the SCUs and monitors the information about whole body movements provided by the SCU sensors. The Master sends overriding commands to the SCUs to control pitch, roll and heave.  The result is body control for handling events that greatly improves vehicle control and speed over terrain. The master controller can also be networked to the vehicle CAN to monitor signals such as speed or steering and use the data in calculating damping commands. The unit can also broadcast information such as error codes on the vehicle network to aid in servicing the system.

Steering Sensor is fitted to the steering shaft of the vehicle. The steering sensor provided direction and rate data to the Master Controller to be used for calculating damping commands in roll events.

Wheel Position Sensor monitors suspension travel and shock piston velocity and provide the information to the SCU and Master Controller. The information is used to determine the proper damping command for the corner and to detect whole body motions of the vehicle.

Optional Ride Selection Switch to select a pre-programmed mode that tunes the suspension response for a defined situation such as “Off Road” or “Track”.

Wiring Harness contains signal and power connections for the SCUs, Master Controller and sensors contained in the system. Wiring can be easily routed through the vehicle chassis with minimal modification.

Customer Installation Tools are computer based and allow the user to configure the system upon installation to match the unique characteristics of the vehicle. Information input by the user includes:

  • Spring Rate
  • Wheel Base
  • Motion Ratio
  • Wheel position sensor calibration

The customer tool also includes a system status screen, fault log and troubleshooting tools to assist the user in installation and diagnostic activities.

Damping Range

The damping is controlled with a patented electronically controlled hydraulic valve that operates in real time. A typical Active Shock semi active damper can provide between 1/2 to 10 times the damping of a standard shock with an industry-leading response time. This means that in a typical landing from a jump that lasts 150 msec, the damper valve will be moved to the optimal damping setting very quickly and will be in control of the vehicle movement and response throughout the event. Typical handling maneuvers last 1-2 seconds, enough time for the system to update the damping -thousands of times during a single handling event. The damping range is an operating area rather than a curve as found in a passive damping system. An example of the damping area can be seen in the Technical Document section.

Bore Size

The Active Shock damper can be designed to fit into any conventional suspension system. The packaging dimensions of the Active Shock semi-active damper are almost identical to a standard shock absorber with the exception of the external control valve and manifold. The nitrogen reservoir can either be direct mounted to the manifold or remote mounted.

Specific packaging requirements can be met on a per application basis. The stroke length and piston diameter are tailored based on the application need for damping force.

Reliability

The mechanical and hydraulic components used are all based on proven robust conventional damper designs. All electro mechanical components are fully waterproof and have been designed for the harsh environment found in the wheel arch of a vehicle. Military versions are capable of full immersion to meet fording requirements. All new components are durability tested on dedicated test rigs and in vehicles over realistic road conditions. Electronics are also subjected to a full battery of EMI and vibration testing.

Active Shock semi active damping systems are typically designed to last the life of the vehicle with zero maintenance. Self-diagnostic software is capable of alerting the operator of the system status if needed. In addition, the control valve was designed to have a benign failure mode; if all power to the controller is lost or a sensor fails the shock defaults to the damping values of a typical passive shock. This allows the vehicle to still be driven however there will be some reduction in performance in off-road and handling events.

Applications

Automotive Aftermarket Shock Absorbers

ASM semi-active ride control technology provides real time control for your suspension system, ending the compromise between performance and ride quality. The patented continuously variable damper valve is controlled by a patented Ride State Aware™ algorithm that reads sensors embedded in the damper and outputs the ideal force target in real time.

General Kinetics Active Shock brand is a world leader in semi-active suspension technology and can provide outstanding shock mitigation performance in the most demanding applications.

Links to General Kinetics current ASM partners are listed below the photo.

Self-Tune and Adjust Algorithm

The ASM system does not require the driver to be a vehicle dynamics expert; the algorithm takes over and optimizes the damping 1000 times per second. Once the system parameters are uploaded into the system at the factory there is absolutely no tuning needed from the user since all the applied damping control is based upon the physics of the system.

The system automatically compensates for changes in vehicle weight due to increases in payload or addition of passengers. The damper targets are adjusted to maintain the desired percent of critical damping despite the change in suspended mass. The algorithm:

  • Knows key system parameters such as spring rate, preload, total travel and unsprung mass
  • Calculates ride height, suspended mass and critical damping rates
  • Adjusts the damping target values to ensure rapid return to ride height with minimal overshoot.

Ride State Aware™ Algorithm

The Ride State Aware™  Algorithm uses a number of different strategies to optimize suspension performance, depending on the instantaneous and longer-term needs of the vehicle.  Our patented algorithm prevents harsh bottoming and topping of the suspension while effectively controlling pitch, heave and transient roll.  Tire contact and traction are maximized and ride comfort is maximized. 

Typical passive suspensions that are optimized for comfort tend to wallow through corners and over expansion joints. Sports cars have stiffer damping for faster response and better control through corners, however they sacrifice ride quality and the driver feels every bump and pothole in the road. The ASM system injects damping only when it is needed for control and keeps the damping force low for ride quality when it is not needed. A sport or race mode switch allows the driver to add compression damping during aggressive driving to improve vehicle response time and to improve road feel.

 

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