Saddle Vehicle Lean Control via Speed-Sensitive Hydraulic Suspension
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Solution Overview
Problem
Conventional saddle riding type vehicles face instability at low speeds and during turns due to resistance from elastic suspension mechanisms and inconvenient operation of antiroll devices, affecting turning performance and rider comfort.
Innovation Solution
A saddle riding type vehicle equipped with a support mechanism for wheels that allows up-and-down movement, an adjusting mechanism controlled by a speed detector and controller to adjust the lean amount based on vehicle speed, and a hydraulic cylinder system for precise operation, ensuring stability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an elastic suspension mechanism is used to support the wheels, then the vehicle has good stability when running at low speed, but the elastic force constantly acts as resistance to changes in position of the vehicle body, lowering turning performance during ordinary run at certain speed or faster
Solution Approach 1:
The suspension mechanism is designed to dynamically change its characteristics based on vehicle speed. At low speeds, the elastic suspension provides stability by restricting body lean. At higher speeds, the system allows greater lean freedom for improved turning performance. This is achieved through a speed-sensitive control system that adjusts the suspension's restraining force accordingly.
Solution Approach 2:
The suspension system's physical parameters (specifically the elastic force characteristics) are changed based on operating conditions. The system transitions from a high-restraint state at low speeds to a low-restraint state at higher speeds, optimizing performance for each speed range by altering the effective stiffness or damping characteristics of the suspension.
2Stability of the object's composition
If an antiroll device is used to prevent leaning of the vehicle body at low speed, then the vehicle has good stability when stopping, but an operation of the antiroll device occurring when the vehicle body is in an unstable position causes an inconvenience of holding the vehicle body in that unstable position
Solution Approach 1:
The antiroll device is designed to operate automatically based on detected vehicle conditions without requiring manual intervention. The control system monitors vehicle speed and lean angle, and activates the antiroll mechanism only when appropriate conditions are met (vehicle upright and at low speed), eliminating the need for rider operation and avoiding the problem of locking the vehicle in unstable positions.
Solution Approach 2:
The system uses feedback from sensors that detect vehicle lean angle and speed to control the antiroll device. The control unit receives information about the vehicle's current state and only activates the antiroll mechanism when the vehicle is in a stable, upright position at low speed, preventing the device from locking the vehicle in unstable positions.
3Ease of operation
If the support mechanism allows the wheels to be movable up and down relative to the vehicle body, then the vehicle can make turns by leaning the vehicle body, but the vehicle is unstable when stopping or running at low speed
Solution Approach 1:
The vehicle employs a dynamic stability control system that adjusts the lean angle characteristics based on vehicle speed. At higher speeds, the vehicle is allowed to lean freely for turning. At low speeds and when stopping, the control system activates to restrict lean motion and maintain stability, creating a speed-dependent lean behavior that optimizes both turning capability and stability.
Solution Approach 2:
The effective lean angle parameter of the vehicle is changed based on operating speed. The control system modifies the relationship between rider input and actual lean angle, or directly controls the lean mechanism, to provide different lean characteristics at different speeds, thereby achieving both free leaning for turns and restricted leaning for stability.
Data Source
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AI summary
A saddle riding type vehicle (1) includes a right rear arm (41R) and a left rear arm (41L) for supporting at least a pair of wheels (43) at opposite sides of a vehicle body to be movable up and down relative to the vehicle body, and a right hydraulic cylinder (71R) and a left hydraulic cylinder (71L) for operating the right rear arm and left rear arm to change a lean amount of the vehicle body. A controller (95) controls the right hydraulic cylinder and left hydraulic cylinder according to vehicle speed. Since the lean amount of the vehicle body can thereby be adjusted according to vehicle speed, both comfortable traveling performance and stability of the vehicle are ensured.