Floor-Mounted Pedal Assembly With Friction Hysteresis Feedback
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Solution Overview
Problem
Existing floor mounted accelerator pedal assemblies lack the ability to provide position sensor output to the powertrain controller and mechanical resistance with hysteresis to the driver's foot during pedal movement.
Innovation Solution
A pedal assembly design that includes a housing with a friction generating member, a link member, a pedal arm, and a lever arm, where the lever arm's hub portion moves against the friction generating member to generate hysteresis, and a sensor assembly tracks the movement to communicate with the powertrain control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a floor mounted accelerator pedal assembly is designed without mechanical resistance, then the pedal can move freely and easily, but the driver receives no hysteresis feedback which degrades the driving experience and control precision
Solution Approach 1:
The patent introduces a friction generating member that changes the friction parameter between the lever arm and housing during pedal movement. The friction is engaged during depression to provide hysteresis feedback, and disengaged during return to maintain ease of operation. This dynamic parameter change resolves the contradiction between movement ease and hysteresis feedback.
Solution Approach 2:
The system dynamically adjusts the mechanical resistance through the friction generating member. The friction is activated when the lever arm moves against the friction generating member during pedal depression, and deactivated when the spring returns the lever arm to its initial position. This dynamic behavior provides hysteresis during the useful action while maintaining ease of return.
2Reliability
If a friction generating member is added to provide hysteresis, then mechanical resistance and feedback are improved, but the device complexity increases
Solution Approach 1:
The friction generating member is integrated with the housing structure, and the hysteresis mechanism is combined with the existing spring-loaded lever arm system. The friction generating member, lever arm, and spring work together as a unified hysteresis assembly, reducing the need for separate complex mechanisms while achieving the desired feedback effect.
3Reliability
If the lever arm continuously contacts the friction generating member, then hysteresis feedback is maintained, but energy loss increases
Solution Approach 1:
The friction contact between the lever arm and friction generating member occurs periodically only during the pedal depression phase when the lever arm moves against the friction surface. During the return phase, the spring pulls the lever arm away from the friction generating member, eliminating friction contact. This periodic engagement minimizes energy loss while maintaining hysteresis feedback during the critical acceleration input.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design provides mechanical resistance and hysteresis feedback to the driver while accurately sensing pedal position for precise control.
Implementation Method 1
The hub portion abuts the friction generating member of the housing and moves when a pressure is applied to the attachment portion. When the pedal arm is depressed, the lever arm leverages a load applied to the pedal arm to move the hub portion against the friction generating member of the housing thereby generating a hysteresis.
Data Source
AI summary
Embodiments herein are directed to pedal assembly for a vehicle that includes a housing, a link member, a pedal arm, and a lever arm. The housing has a friction generating member extending from an interior surface of a sidewall. The pedal arm is coupled to a first end of the link member. The lever arm has a second lever end that includes a hub portion. A first lever end includes an attachment portion extending from an exterior surface. The attachment portion is coupled to the second end of the link member. The hub portion abuts the friction generating member of the housing and moves when a pressure is applied to the attachment portion. When the pedal arm is depressed, the lever arm leverages a load applied to the pedal arm to move the hub portion against the friction generating member of the housing thereby generating a hysteresis.