Snowmobile Rear Suspension Sensing for Active Damping Control
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Solution Overview
Problem
Uncoupled rear suspension assemblies in snowmobiles pose a challenge for active control of suspension damping, as sensors connected to rigid members cannot accurately determine the piston movement or position of shock absorbers due to independent movement of front and rear suspension components.
Innovation Solution
Incorporating two sensors to measure the angular position and velocity of rear suspension arms, allowing the determination of stroke and piston velocity of shock absorbers, even in uncoupled geometries, and using a controller to adjust damping based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are connected to rigid members of the suspension assembly to determine piston movement, then active control of suspension damping can be achieved, but in uncoupled rear suspension assemblies the sensors cannot accurately determine piston movement or position due to independent movement of front and rear suspension components
Solution Approach 1:
The patent introduces an intermediary computational approach where a processor calculates piston position and velocity by integrating data from multiple sensors (accelerometers, gyroscopes, and position sensors) rather than relying on a single direct sensor connection. This intermediary computation layer resolves the contradiction by deriving accurate piston movement data through mathematical integration of indirect measurements, making the system compatible with uncoupled suspension geometries while maintaining measurement precision.
2Measurement precision
If shock absorbers with internal sensors are used to determine piston movement, then accurate measurement can be achieved, but the position sensors and shock absorbers become more expensive and more complicated to repair or replace
Solution Approach 1:
The patent segments the measurement system into separate functional components: external sensors (accelerometers, gyroscopes, position sensors) mounted on suspension arms and a central processor that computes piston movement. This segmentation allows the sensors to be independent, replaceable units rather than integrated internal components, resolving the contradiction by maintaining measurement precision through distributed sensing while improving ease of repair through modular architecture.
3Reliability
If active control of suspension damping is implemented, then ride comfort and handling are improved, but the system complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The patent implements multi-functionality by using a single processor to perform multiple tasks: integrating sensor data, calculating piston position and velocity, determining shock absorber state, and controlling damping forces. This universal processor approach resolves the contradiction by consolidating control functions into one component rather than requiring separate dedicated systems, thereby improving ride comfort and handling while minimizing the increase in overall system complexity.
Data Source
AI summary
A snowmobile including a chassis including a tunnel; a motor; at least one ski; an endless drive track; a rear suspension assembly including: a front suspension arm; a rear suspension arm; a pair of slide rails; a first rear shock absorber connected between the front suspension arm and the slide rails; and a second rear shock absorber connected between the rear suspension arm and the front suspension arm or the slide rails; at least one sensor for sensing an angular position of the front suspension arm or the rear suspension arm relative to one of the tunnel and a component of the rear suspension assembly near at least one of the front suspension arm and the rear suspension arm; and a controller communicatively connected to the sensor to receive electronic signals therefrom representative of the angular position.