Vehicle Pedal Reaction Force Control via Acceleration-Dependent Rigidity
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Solution Overview
Problem
Conventional by-wire mechanisms in vehicles fail to provide an intuitive operating sensation that matches the vehicle's behavior, leading to discomfort for operators due to mismatched pedal reaction forces and vehicle acceleration.
Innovation Solution
A control system that includes an operating amount detector, speed detector, and reaction-force generator, with a controller that calculates acceleration and adjusts the reaction force to match the vehicle's behavior, using a rigidity characteristic map to differentiate between acceleration ranges and gear positions, ensuring a harmonious operator sensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the reaction force is made proportional to the accelerator pedal speed to improve operability, then the operator can quickly operate the pedal with smaller operating force, but the operating sensation becomes inverted relative to vehicle acceleration causing operator discomfort
Solution Approach 1:
The patent applies dynamics by making the reaction force characteristic changeable based on vehicle acceleration state. The control unit dynamically adjusts the reaction force formula between two modes: proportional to pedal speed (for quick operation) and proportional to pedal position (for matching vehicle behavior). This dynamic switching resolves the contradiction by adapting the reaction force characteristic to the current driving situation, allowing both quick operability and intuitive sensation to be achieved at different times.
Solution Approach 2:
The patent changes the parameter of reaction force proportionality from purely speed-based to acceleration-state-dependent. By introducing vehicle acceleration as a control parameter, the system selects between two different reaction force formulations. This parameter change enables the reaction force to reflect both pedal operation speed (for ease of operation) and vehicle acceleration state (for intuitive sensation), resolving the contradiction through multi-parameter control.
2Object-generated harmful factors
If the reaction force increases with vehicle acceleration to match intuitive sensation, then the operating sensation matches vehicle behavior, but the operator experiences increased workload when quick operation is needed
Solution Approach 1:
The system dynamically adjusts the reaction force characteristic based on real-time acceleration detection. When acceleration is low or negative, the reaction force is proportional to pedal position, providing intuitive sensation matching. When acceleration is high or quick operation is detected, the reaction force switches to being proportional to pedal speed, reducing operator workload. This dynamic adaptation resolves the contradiction between matching sensation and minimizing workload.
Solution Approach 2:
The patent changes the reaction force parameter from fixed proportionality to acceleration-state-dependent proportionality. By using vehicle acceleration as a switching parameter, the system selects between position-proportional (for sensation matching) and speed-proportional (for reduced workload) reaction forces. This parameter-based control resolves the contradiction by allowing both characteristics to coexist in different operating conditions.
3Object-generated harmful factors
If the reaction force is proportional to accelerator pedal position to improve operating sensation, then the physical sensation matches vehicle behavior, but the reaction force decreases when vehicle accelerates from low speed causing mismatched sensation
Solution Approach 1:
The patent implements dynamic switching between two reaction force characteristics based on vehicle acceleration. When acceleration is low, position-proportional reaction force provides intuitive sensation matching. When acceleration is high or during quick operations, speed-proportional reaction force provides easier operation. This dynamic adjustment resolves the contradiction by allowing both sensation matching and operation ease to be optimized in their respective conditions.
Solution Approach 2:
The system changes the reaction force parameter from position-proportional to acceleration-state-dependent. By introducing vehicle acceleration as a control parameter, the system switches between position-proportional (for sensation matching) and speed-proportional (for operation ease) characteristics. This parameter-based switching resolves the contradiction by enabling both characteristics to function optimally in different acceleration regimes.
Data Source
AI summary
A vehicle control system is provided, which includes an operating amount detector configured to detect an operating amount by an operator, of an operation mechanism comprising at least one of an accelerator pedal and a brake pedal, a speed detector configured to detect a vehicle traveling speed, a reaction-force generator configured to generate a reaction force of the pedal, and a controller. The controller includes a processor to execute an acceleration calculating module to calculate an acceleration based on the traveling speed and the operating amount, a rigidity characteristic setting module to set the reaction force so that a rigidity value that is a ratio of the reaction force to the operating amount increases as the acceleration increases, and a reaction-force control module to control the reaction-force generator so that the reaction force generated by the reaction-force generator becomes the reaction-force value set by the rigidity characteristic setting module.